1# SPDX-License-Identifier: GPL-2.0-only 2menu "Kernel hacking" 3 4menu "printk and dmesg options" 5 6config PRINTK_TIME 7 bool "Show timing information on printks" 8 depends on PRINTK 9 help 10 Selecting this option causes time stamps of the printk() 11 messages to be added to the output of the syslog() system 12 call and at the console. 13 14 The timestamp is always recorded internally, and exported 15 to /dev/kmsg. This flag just specifies if the timestamp should 16 be included, not that the timestamp is recorded. 17 18 The behavior is also controlled by the kernel command line 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst 20 21config PRINTK_CALLER 22 bool "Show caller information on printks" 23 depends on PRINTK 24 help 25 Selecting this option causes printk() to add a caller "thread id" (if 26 in task context) or a caller "processor id" (if not in task context) 27 to every message. 28 29 This option is intended for environments where multiple threads 30 concurrently call printk() for many times, for it is difficult to 31 interpret without knowing where these lines (or sometimes individual 32 line which was divided into multiple lines due to race) came from. 33 34 Since toggling after boot makes the code racy, currently there is 35 no option to enable/disable at the kernel command line parameter or 36 sysfs interface. 37 38config PRINTK_EXECUTION_CTX 39 bool 40 depends on PRINTK 41 help 42 This option extends struct printk_info to include extra execution 43 context in printk, such as task name and CPU number from where the 44 message originated. This is useful for correlating printk messages 45 with specific execution contexts. 46 47 This is automatically enabled when a console driver that supports 48 execution context is selected. 49 50config STACKTRACE_BUILD_ID 51 bool "Show build ID information in stacktraces" 52 depends on PRINTK 53 help 54 Selecting this option adds build ID information for symbols in 55 stacktraces printed with the printk format '%p[SR]b'. 56 57 This option is intended for distros where debuginfo is not easily 58 accessible but can be downloaded given the build ID of the vmlinux or 59 kernel module where the function is located. 60 61config CONSOLE_LOGLEVEL_DEFAULT 62 int "Default console loglevel (1-15)" 63 range 1 15 64 default "7" 65 help 66 Default loglevel to determine what will be printed on the console. 67 68 Setting a default here is equivalent to passing in loglevel=<x> in 69 the kernel bootargs. loglevel=<x> continues to override whatever 70 value is specified here as well. 71 72 Note: This does not affect the log level of un-prefixed printk() 73 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT 74 option. 75 76config CONSOLE_LOGLEVEL_QUIET 77 int "quiet console loglevel (1-15)" 78 range 1 15 79 default "4" 80 help 81 loglevel to use when "quiet" is passed on the kernel commandline. 82 83 When "quiet" is passed on the kernel commandline this loglevel 84 will be used as the loglevel. IOW passing "quiet" will be the 85 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" 86 87config MESSAGE_LOGLEVEL_DEFAULT 88 int "Default message log level (1-7)" 89 range 1 7 90 default "4" 91 help 92 Default log level for printk statements with no specified priority. 93 94 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks 95 that are auditing their logs closely may want to set it to a lower 96 priority. 97 98 Note: This does not affect what message level gets printed on the console 99 by default. To change that, use loglevel=<x> in the kernel bootargs, 100 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. 101 102config BOOT_PRINTK_DELAY 103 bool "Delay each boot printk message by N milliseconds" 104 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY 105 help 106 This build option allows you to read kernel boot messages 107 by inserting a short delay after each one. The delay is 108 specified in milliseconds on the kernel command line, 109 using "boot_delay=N". 110 111 It is likely that you would also need to use "lpj=M" to preset 112 the "loops per jiffy" value. 113 See a previous boot log for the "lpj" value to use for your 114 system, and then set "lpj=M" before setting "boot_delay=N". 115 NOTE: Using this option may adversely affect SMP systems. 116 I.e., processors other than the first one may not boot up. 117 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect 118 what it believes to be lockup conditions. 119 120config DYNAMIC_DEBUG 121 bool "Enable dynamic printk() support" 122 default n 123 depends on PRINTK 124 depends on (DEBUG_FS || PROC_FS) 125 select DYNAMIC_DEBUG_CORE 126 help 127 128 Compiles debug level messages into the kernel, which would not 129 otherwise be available at runtime. These messages can then be 130 enabled/disabled based on various levels of scope - per source file, 131 function, module, format string, and line number. This mechanism 132 implicitly compiles in all pr_debug() and dev_dbg() calls, which 133 enlarges the kernel text size by about 2%. 134 135 If a source file is compiled with DEBUG flag set, any 136 pr_debug() calls in it are enabled by default, but can be 137 disabled at runtime as below. Note that DEBUG flag is 138 turned on by many CONFIG_*DEBUG* options. 139 140 Usage: 141 142 Dynamic debugging is controlled via the 'dynamic_debug/control' file, 143 which is contained in the 'debugfs' filesystem or procfs. 144 Thus, the debugfs or procfs filesystem must first be mounted before 145 making use of this feature. 146 We refer the control file as: <debugfs>/dynamic_debug/control. This 147 file contains a list of the debug statements that can be enabled. The 148 format for each line of the file is: 149 150 filename:lineno [module]function flags format 151 152 filename : source file of the debug statement 153 lineno : line number of the debug statement 154 module : module that contains the debug statement 155 function : function that contains the debug statement 156 flags : '=p' means the line is turned 'on' for printing 157 format : the format used for the debug statement 158 159 From a live system: 160 161 nullarbor:~ # cat <debugfs>/dynamic_debug/control 162 # filename:lineno [module]function flags format 163 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" 164 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" 165 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" 166 167 Example usage: 168 169 // enable the message at line 1603 of file svcsock.c 170 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > 171 <debugfs>/dynamic_debug/control 172 173 // enable all the messages in file svcsock.c 174 nullarbor:~ # echo -n 'file svcsock.c +p' > 175 <debugfs>/dynamic_debug/control 176 177 // enable all the messages in the NFS server module 178 nullarbor:~ # echo -n 'module nfsd +p' > 179 <debugfs>/dynamic_debug/control 180 181 // enable all 12 messages in the function svc_process() 182 nullarbor:~ # echo -n 'func svc_process +p' > 183 <debugfs>/dynamic_debug/control 184 185 // disable all 12 messages in the function svc_process() 186 nullarbor:~ # echo -n 'func svc_process -p' > 187 <debugfs>/dynamic_debug/control 188 189 See Documentation/admin-guide/dynamic-debug-howto.rst for additional 190 information. 191 192config DYNAMIC_DEBUG_CORE 193 bool "Enable core function of dynamic debug support" 194 depends on PRINTK 195 depends on (DEBUG_FS || PROC_FS) 196 help 197 Enable core functional support of dynamic debug. It is useful 198 when you want to tie dynamic debug to your kernel modules with 199 DYNAMIC_DEBUG_MODULE defined for each of them, especially for 200 the case of embedded system where the kernel image size is 201 sensitive for people. 202 203config SYMBOLIC_ERRNAME 204 bool "Support symbolic error names in printf" 205 default y if PRINTK 206 help 207 If you say Y here, the kernel's printf implementation will 208 be able to print symbolic error names such as ENOSPC instead 209 of the number 28. It makes the kernel image slightly larger 210 (about 3KB), but can make the kernel logs easier to read. 211 212config DEBUG_BUGVERBOSE 213 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT 214 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) 215 default y 216 help 217 Say Y here to make BUG() panics output the file name and line number 218 of the BUG call as well as the EIP and oops trace. This aids 219 debugging but costs about 70-100K of memory. 220 221config DEBUG_BUGVERBOSE_DETAILED 222 bool "Verbose WARN_ON_ONCE() reporting (adds 100K)" if DEBUG_BUGVERBOSE 223 help 224 Say Y here to make WARN_ON_ONCE() output the condition string of the 225 warning, in addition to the file name and line number. 226 This helps debugging, but costs about 100K of memory. 227 228 Say N if unsure. 229 230 231endmenu # "printk and dmesg options" 232 233config DEBUG_KERNEL 234 bool "Kernel debugging" 235 help 236 Say Y here if you are developing drivers or trying to debug and 237 identify kernel problems. 238 239config DEBUG_MISC 240 bool "Miscellaneous debug code" 241 default DEBUG_KERNEL 242 depends on DEBUG_KERNEL 243 help 244 Say Y here if you need to enable miscellaneous debug code that should 245 be under a more specific debug option but isn't. 246 247menu "Compile-time checks and compiler options" 248 249config DEBUG_INFO 250 bool 251 help 252 A kernel debug info option other than "None" has been selected 253 in the "Debug information" choice below, indicating that debug 254 information will be generated for build targets. 255 256# Clang generates .uleb128 with label differences for DWARF v5, a feature that 257# older binutils ports do not support when utilizing RISC-V style linker 258# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 259config AS_HAS_NON_CONST_ULEB128 260 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) 261 262choice 263 prompt "Debug information" 264 depends on DEBUG_KERNEL 265 help 266 Selecting something other than "None" results in a kernel image 267 that will include debugging info resulting in a larger kernel image. 268 This adds debug symbols to the kernel and modules (gcc -g), and 269 is needed if you intend to use kernel crashdump or binary object 270 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 271 272 Choose which version of DWARF debug info to emit. If unsure, 273 select "Toolchain default". 274 275config DEBUG_INFO_NONE 276 bool "Disable debug information" 277 help 278 Do not build the kernel with debugging information, which will 279 result in a faster and smaller build. 280 281config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 282 bool "Rely on the toolchain's implicit default DWARF version" 283 select DEBUG_INFO 284 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) 285 help 286 The implicit default version of DWARF debug info produced by a 287 toolchain changes over time. 288 289 This can break consumers of the debug info that haven't upgraded to 290 support newer revisions, and prevent testing newer versions, but 291 those should be less common scenarios. 292 293config DEBUG_INFO_DWARF4 294 bool "Generate DWARF Version 4 debuginfo" 295 select DEBUG_INFO 296 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502) 297 help 298 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2 299 if using clang without clang's integrated assembler, and gdb 7.0+. 300 301 If you have consumers of DWARF debug info that are not ready for 302 newer revisions of DWARF, you may wish to choose this or have your 303 config select this. 304 305config DEBUG_INFO_DWARF5 306 bool "Generate DWARF Version 5 debuginfo" 307 select DEBUG_INFO 308 depends on !ARCH_HAS_BROKEN_DWARF5 309 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) 310 help 311 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 312 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 313 draft features until 7.0), and gdb 8.0+. 314 315 Changes to the structure of debug info in Version 5 allow for around 316 15-18% savings in resulting image and debug info section sizes as 317 compared to DWARF Version 4. DWARF Version 5 standardizes previous 318 extensions such as accelerators for symbol indexing and the format 319 for fission (.dwo/.dwp) files. Users may not want to select this 320 config if they rely on tooling that has not yet been updated to 321 support DWARF Version 5. 322 323endchoice # "Debug information" 324 325if DEBUG_INFO 326 327config DEBUG_INFO_REDUCED 328 bool "Reduce debugging information" 329 help 330 If you say Y here gcc is instructed to generate less debugging 331 information for structure types. This means that tools that 332 need full debugging information (like kgdb or systemtap) won't 333 be happy. But if you merely need debugging information to 334 resolve line numbers there is no loss. Advantage is that 335 build directory object sizes shrink dramatically over a full 336 DEBUG_INFO build and compile times are reduced too. 337 Only works with newer gcc versions. 338 339choice 340 prompt "Compressed Debug information" 341 help 342 Compress the resulting debug info. Results in smaller debug info sections, 343 but requires that consumers are able to decompress the results. 344 345 If unsure, choose DEBUG_INFO_COMPRESSED_NONE. 346 347config DEBUG_INFO_COMPRESSED_NONE 348 bool "Don't compress debug information" 349 help 350 Don't compress debug info sections. 351 352config DEBUG_INFO_COMPRESSED_ZLIB 353 bool "Compress debugging information with zlib" 354 depends on $(cc-option,-gz=zlib) 355 depends on $(ld-option,--compress-debug-sections=zlib) 356 help 357 Compress the debug information using zlib. 358 359 Users of dpkg-deb via debian/rules may find an increase in 360 size of their debug .deb packages with this config set, due to the 361 debug info being compressed with zlib, then the object files being 362 recompressed with a different compression scheme. But this is still 363 preferable to setting KDEB_COMPRESS or DPKG_DEB_COMPRESSOR_TYPE to 364 "none" which would be even larger. 365 366config DEBUG_INFO_COMPRESSED_ZSTD 367 bool "Compress debugging information with zstd" 368 depends on $(cc-option,-gz=zstd) 369 depends on $(ld-option,--compress-debug-sections=zstd) 370 help 371 Compress the debug information using zstd. This may provide better 372 compression than zlib, for about the same time costs, but requires newer 373 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and 374 zstd. 375 376endchoice # "Compressed Debug information" 377 378config DEBUG_INFO_SPLIT 379 bool "Produce split debuginfo in .dwo files" 380 depends on $(cc-option,-gsplit-dwarf) 381 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC 382 # prior to 12.x: 383 # https://github.com/llvm/llvm-project/issues/56642 384 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 385 depends on !RISCV || GCC_VERSION >= 120000 386 help 387 Generate debug info into separate .dwo files. This significantly 388 reduces the build directory size for builds with DEBUG_INFO, 389 because it stores the information only once on disk in .dwo 390 files instead of multiple times in object files and executables. 391 In addition the debug information is also compressed. 392 393 Requires recent gcc (4.7+) and recent gdb/binutils. 394 Any tool that packages or reads debug information would need 395 to know about the .dwo files and include them. 396 Incompatible with older versions of ccache. 397 398config DEBUG_INFO_BTF 399 bool "Generate BTF type information" 400 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 401 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 402 depends on BPF_SYSCALL 403 depends on PAHOLE_VERSION >= 122 404 # pahole uses elfutils, which does not have support for Hexagon relocations 405 depends on !HEXAGON 406 help 407 Generate deduplicated BTF type information from DWARF debug info. 408 Turning this on requires pahole v1.22 or later, which will convert 409 DWARF type info into equivalent deduplicated BTF type info. 410 411config PAHOLE_HAS_BTF_TAG 412 def_bool PAHOLE_VERSION >= 123 413 depends on CC_IS_CLANG 414 help 415 Decide whether pahole emits btf_tag attributes (btf_type_tag and 416 btf_decl_tag) or not. Currently only clang compiler implements 417 these attributes, so make the config depend on CC_IS_CLANG. 418 419config PAHOLE_HAS_LANG_EXCLUDE 420 def_bool PAHOLE_VERSION >= 124 421 help 422 Support for the --lang_exclude flag which makes pahole exclude 423 compilation units from the supplied language. Used in Kbuild to 424 omit Rust CUs which are not supported in version 1.24 of pahole, 425 otherwise it would emit malformed kernel and module binaries when 426 using DEBUG_INFO_BTF_MODULES. 427 428config DEBUG_INFO_BTF_MODULES 429 bool "Generate BTF type information for kernel modules" 430 default y 431 depends on DEBUG_INFO_BTF && MODULES 432 help 433 Generate compact split BTF type information for kernel modules. 434 435config MODULE_ALLOW_BTF_MISMATCH 436 bool "Allow loading modules with non-matching BTF type info" 437 depends on DEBUG_INFO_BTF_MODULES 438 help 439 For modules whose split BTF does not match vmlinux, load without 440 BTF rather than refusing to load. The default behavior with 441 module BTF enabled is to reject modules with such mismatches; 442 this option will still load module BTF where possible but ignore 443 it when a mismatch is found. 444 445config GDB_SCRIPTS 446 bool "Provide GDB scripts for kernel debugging" 447 help 448 This creates the required links to GDB helper scripts in the 449 build directory. If you load vmlinux into gdb, the helper 450 scripts will be automatically imported by gdb as well, and 451 additional functions are available to analyze a Linux kernel 452 instance. See Documentation/process/debugging/gdb-kernel-debugging.rst 453 for further details. 454 455endif # DEBUG_INFO 456 457config FRAME_WARN 458 int "Warn for stack frames larger than" 459 range 0 8192 460 default 0 if KMSAN 461 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 462 default 2048 if PARISC 463 default 1536 if (!64BIT && XTENSA) 464 default 1280 if !64BIT 465 default 2048 if 64BIT 466 help 467 Tell the compiler to warn at build time for stack frames larger than this. 468 Setting this too low will cause a lot of warnings. 469 Setting it to 0 disables the warning. 470 471config STRIP_ASM_SYMS 472 bool "Strip assembler-generated symbols during link" 473 default n 474 help 475 Strip internal assembler-generated symbols during a link (symbols 476 that look like '.Lxxx') so they don't pollute the output of 477 get_wchan() and suchlike. 478 479config READABLE_ASM 480 bool "Generate readable assembler code" 481 depends on DEBUG_KERNEL 482 depends on CC_IS_GCC 483 help 484 Disable some compiler optimizations that tend to generate human unreadable 485 assembler output. This may make the kernel slightly slower, but it helps 486 to keep kernel developers who have to stare a lot at assembler listings 487 sane. 488 489config HEADERS_INSTALL 490 bool "Install uapi headers to usr/include" 491 help 492 This option will install uapi headers (headers exported to user-space) 493 into the usr/include directory for use during the kernel build. 494 This is unneeded for building the kernel itself, but needed for some 495 user-space program samples. It is also needed by some features such 496 as uapi header sanity checks. 497 498config DEBUG_SECTION_MISMATCH 499 bool "Enable full Section mismatch analysis" 500 depends on CC_IS_GCC 501 help 502 The section mismatch analysis checks if there are illegal references 503 from one section to another. During linktime or runtime, some 504 sections are dropped; any use of code/data previously in these 505 sections would most likely result in an oops. 506 507 In the code, functions and variables are annotated with __init, 508 __initdata, and so on (see the full list in include/linux/init.h). 509 This directs the toolchain to place code/data in specific sections. 510 511 The section mismatch analysis is always performed after a full 512 kernel build, and enabling this option causes the option 513 -fno-inline-functions-called-once to be added to gcc commands. 514 515 However, when inlining a function annotated with __init in 516 a non-init function, we would lose the section information and thus 517 the analysis would not catch the illegal reference. This option 518 tells gcc to inline less (but it does result in a larger kernel). 519 520config SECTION_MISMATCH_WARN_ONLY 521 bool "Make section mismatch errors non-fatal" 522 default y 523 help 524 If you say N here, the build process will fail if there are any 525 section mismatch, instead of just throwing warnings. 526 527 If unsure, say Y. 528 529config DEBUG_FORCE_FUNCTION_ALIGN_64B 530 bool "Force all function address 64B aligned" 531 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390) 532 select FUNCTION_ALIGNMENT_64B 533 help 534 There are cases that a commit from one domain changes the function 535 address alignment of other domains, and cause magic performance 536 bump (regression or improvement). Enable this option will help to 537 verify if the bump is caused by function alignment changes, while 538 it will slightly increase the kernel size and affect icache usage. 539 540 It is mainly for debug and performance tuning use. 541 542# 543# Select this config option from the architecture Kconfig, if it 544# is preferred to always offer frame pointers as a config 545# option on the architecture (regardless of KERNEL_DEBUG): 546# 547config ARCH_WANT_FRAME_POINTERS 548 bool 549 550config FRAME_POINTER 551 bool "Compile the kernel with frame pointers" 552 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 553 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 554 help 555 If you say Y here the resulting kernel image will be slightly 556 larger and slower, but it gives very useful debugging information 557 in case of kernel bugs. (precise oopses/stacktraces/warnings) 558 559config OBJTOOL 560 bool 561 562config OBJTOOL_WERROR 563 bool "Upgrade objtool warnings to errors" 564 depends on OBJTOOL && !COMPILE_TEST 565 help 566 Fail the build on objtool warnings. 567 568 Objtool warnings can indicate kernel instability, including boot 569 failures. This option is highly recommended. 570 571 If unsure, say Y. 572 573config STACK_VALIDATION 574 bool "Compile-time stack metadata validation" 575 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 576 select OBJTOOL 577 default n 578 help 579 Validate frame pointer rules at compile-time. This helps ensure that 580 runtime stack traces are more reliable. 581 582 For more information, see 583 tools/objtool/Documentation/objtool.txt. 584 585config NOINSTR_VALIDATION 586 bool 587 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 588 select OBJTOOL 589 default y 590 591config VMLINUX_MAP 592 bool "Generate vmlinux.map file when linking" 593 depends on EXPERT 594 help 595 Selecting this option will pass "-Map=vmlinux.map" to ld 596 when linking vmlinux. That file can be useful for verifying 597 and debugging magic section games, and for seeing which 598 pieces of code get eliminated with 599 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 600 601config BUILTIN_MODULE_RANGES 602 bool "Generate address range information for builtin modules" 603 depends on !LTO 604 depends on VMLINUX_MAP 605 help 606 When modules are built into the kernel, there will be no module name 607 associated with its symbols in /proc/kallsyms. Tracers may want to 608 identify symbols by module name and symbol name regardless of whether 609 the module is configured as loadable or not. 610 611 This option generates modules.builtin.ranges in the build tree with 612 offset ranges (per ELF section) for the module(s) they belong to. 613 It also records an anchor symbol to determine the load address of the 614 section. 615 616config DEBUG_FORCE_WEAK_PER_CPU 617 bool "Force weak per-cpu definitions" 618 depends on DEBUG_KERNEL 619 help 620 s390 and alpha require percpu variables in modules to be 621 defined weak to work around addressing range issue which 622 puts the following two restrictions on percpu variable 623 definitions. 624 625 1. percpu symbols must be unique whether static or not 626 2. percpu variables can't be defined inside a function 627 628 To ensure that generic code follows the above rules, this 629 option forces all percpu variables to be defined as weak. 630 631config WARN_CONTEXT_ANALYSIS 632 bool "Compiler context-analysis warnings" 633 depends on CC_IS_CLANG && CLANG_VERSION >= 220000 634 # Branch profiling re-defines "if", which messes with the compiler's 635 # ability to analyze __cond_acquires(..), resulting in false positives. 636 depends on !TRACE_BRANCH_PROFILING 637 default y 638 help 639 Context Analysis is a language extension, which enables statically 640 checking that required contexts are active (or inactive) by acquiring 641 and releasing user-definable "context locks". 642 643 Clang's name of the feature is "Thread Safety Analysis". Requires 644 Clang 22 or later. 645 646 Produces warnings by default. Select CONFIG_WERROR if you wish to 647 turn these warnings into errors. 648 649 For more details, see Documentation/dev-tools/context-analysis.rst. 650 651config WARN_CONTEXT_ANALYSIS_ALL 652 bool "Enable context analysis for all source files" 653 depends on WARN_CONTEXT_ANALYSIS 654 depends on EXPERT && !COMPILE_TEST 655 help 656 Enable tree-wide context analysis. This is likely to produce a 657 large number of false positives - enable at your own risk. 658 659 If unsure, say N. 660 661endmenu # "Compiler options" 662 663menu "Generic Kernel Debugging Instruments" 664 665config MAGIC_SYSRQ 666 bool "Magic SysRq key" 667 depends on !UML 668 help 669 If you say Y here, you will have some control over the system even 670 if the system crashes for example during kernel debugging (e.g., you 671 will be able to flush the buffer cache to disk, reboot the system 672 immediately or dump some status information). This is accomplished 673 by pressing various keys while holding SysRq (Alt+PrintScreen). It 674 also works on a serial console (on PC hardware at least), if you 675 send a BREAK and then within 5 seconds a command keypress. The 676 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 677 Don't say Y unless you really know what this hack does. 678 679config MAGIC_SYSRQ_DEFAULT_ENABLE 680 hex "Enable magic SysRq key functions by default" 681 depends on MAGIC_SYSRQ 682 default 0x1 683 help 684 Specifies which SysRq key functions are enabled by default. 685 This may be set to 1 or 0 to enable or disable them all, or 686 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 687 688config MAGIC_SYSRQ_SERIAL 689 bool "Enable magic SysRq key over serial" 690 depends on MAGIC_SYSRQ 691 default y 692 help 693 Many embedded boards have a disconnected TTL level serial which can 694 generate some garbage that can lead to spurious false sysrq detects. 695 This option allows you to decide whether you want to enable the 696 magic SysRq key. 697 698config MAGIC_SYSRQ_SERIAL_SEQUENCE 699 string "Char sequence that enables magic SysRq over serial" 700 depends on MAGIC_SYSRQ_SERIAL 701 default "" 702 help 703 Specifies a sequence of characters that can follow BREAK to enable 704 SysRq on a serial console. 705 706 If unsure, leave an empty string and the option will not be enabled. 707 708config DEBUG_FS 709 bool "Debug Filesystem" 710 help 711 debugfs is a virtual file system that kernel developers use to put 712 debugging files into. Enable this option to be able to read and 713 write to these files. 714 715 For detailed documentation on the debugfs API, see 716 Documentation/filesystems/. 717 718 If unsure, say N. 719 720choice 721 prompt "Debugfs default access" 722 depends on DEBUG_FS 723 default DEBUG_FS_ALLOW_ALL 724 help 725 This selects the default access restrictions for debugfs. 726 It can be overridden with kernel command line option 727 debugfs=[on,off]. The restrictions apply for API access 728 and filesystem registration. 729 730config DEBUG_FS_ALLOW_ALL 731 bool "Access normal" 732 help 733 No restrictions apply. Both API and filesystem registration 734 is on. This is the normal default operation. 735 736config DEBUG_FS_ALLOW_NONE 737 bool "No access" 738 help 739 Access is off. Clients get -PERM when trying to create nodes in 740 debugfs tree and debugfs is not registered as a filesystem. 741 Client can then back-off or continue without debugfs access. 742 743endchoice 744 745source "lib/Kconfig.kgdb" 746source "lib/Kconfig.ubsan" 747source "lib/Kconfig.kcsan" 748 749endmenu 750 751menu "Networking Debugging" 752 753source "net/Kconfig.debug" 754 755endmenu # "Networking Debugging" 756 757menu "Memory Debugging" 758 759source "mm/Kconfig.debug" 760 761config DEBUG_OBJECTS 762 bool "Debug object operations" 763 depends on DEBUG_KERNEL 764 help 765 If you say Y here, additional code will be inserted into the 766 kernel to track the life time of various objects and validate 767 the operations on those objects. 768 769config DEBUG_OBJECTS_SELFTEST 770 bool "Debug objects selftest" 771 depends on DEBUG_OBJECTS 772 help 773 This enables the selftest of the object debug code. 774 775config DEBUG_OBJECTS_FREE 776 bool "Debug objects in freed memory" 777 depends on DEBUG_OBJECTS 778 help 779 This enables checks whether a k/v free operation frees an area 780 which contains an object which has not been deactivated 781 properly. This can make kmalloc/kfree-intensive workloads 782 much slower. 783 784config DEBUG_OBJECTS_TIMERS 785 bool "Debug timer objects" 786 depends on DEBUG_OBJECTS 787 help 788 If you say Y here, additional code will be inserted into the 789 timer routines to track the life time of timer objects and 790 validate the timer operations. 791 792config DEBUG_OBJECTS_WORK 793 bool "Debug work objects" 794 depends on DEBUG_OBJECTS 795 help 796 If you say Y here, additional code will be inserted into the 797 work queue routines to track the life time of work objects and 798 validate the work operations. 799 800config DEBUG_OBJECTS_RCU_HEAD 801 bool "Debug RCU callbacks objects" 802 depends on DEBUG_OBJECTS 803 help 804 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 805 806config DEBUG_OBJECTS_PERCPU_COUNTER 807 bool "Debug percpu counter objects" 808 depends on DEBUG_OBJECTS 809 help 810 If you say Y here, additional code will be inserted into the 811 percpu counter routines to track the life time of percpu counter 812 objects and validate the percpu counter operations. 813 814config DEBUG_OBJECTS_ENABLE_DEFAULT 815 int "debug_objects bootup default value (0-1)" 816 range 0 1 817 default "1" 818 depends on DEBUG_OBJECTS 819 help 820 Debug objects boot parameter default value 821 822config SHRINKER_DEBUG 823 bool "Enable shrinker debugging support" 824 depends on DEBUG_FS 825 help 826 Say Y to enable the shrinker debugfs interface which provides 827 visibility into the kernel memory shrinkers subsystem. 828 Disable it to avoid an extra memory footprint. 829 830config DEBUG_STACK_USAGE 831 bool "Stack utilization instrumentation" 832 depends on DEBUG_KERNEL 833 help 834 Enables the display of the minimum amount of free stack which each 835 task has ever had available in the sysrq-T and sysrq-P debug output. 836 Also emits a message to dmesg when a process exits if that process 837 used more stack space than previously exiting processes. 838 839 This option will slow down process creation somewhat. 840 841config SCHED_STACK_END_CHECK 842 bool "Detect stack corruption on calls to schedule()" 843 depends on DEBUG_KERNEL 844 default n 845 help 846 This option checks for a stack overrun on calls to schedule(). 847 If the stack end location is found to be over written always panic as 848 the content of the corrupted region can no longer be trusted. 849 This is to ensure no erroneous behaviour occurs which could result in 850 data corruption or a sporadic crash at a later stage once the region 851 is examined. The runtime overhead introduced is minimal. 852 853config ARCH_HAS_DEBUG_VM_PGTABLE 854 bool 855 help 856 An architecture should select this when it can successfully 857 build and run DEBUG_VM_PGTABLE. 858 859config DEBUG_VFS 860 bool "Debug VFS" 861 depends on DEBUG_KERNEL 862 help 863 Enable this to turn on extended checks in the VFS layer that may impact 864 performance. 865 866 If unsure, say N. 867 868config DEBUG_VM_IRQSOFF 869 def_bool DEBUG_VM && !PREEMPT_RT 870 871config DEBUG_VM 872 bool "Debug VM" 873 depends on DEBUG_KERNEL 874 help 875 Enable this to turn on extended checks in the virtual-memory system 876 that may impact performance. 877 878 If unsure, say N. 879 880config DEBUG_VM_SHOOT_LAZIES 881 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation" 882 depends on DEBUG_VM 883 depends on MMU_LAZY_TLB_SHOOTDOWN 884 help 885 Enable additional IPIs that ensure lazy tlb mm references are removed 886 before the mm is freed. 887 888 If unsure, say N. 889 890config DEBUG_VM_MAPLE_TREE 891 bool "Debug VM maple trees" 892 depends on DEBUG_VM 893 select DEBUG_MAPLE_TREE 894 help 895 Enable VM maple tree debugging information and extra validations. 896 897 If unsure, say N. 898 899config DEBUG_VM_RB 900 bool "Debug VM red-black trees" 901 depends on DEBUG_VM 902 help 903 Enable VM red-black tree debugging information and extra validations. 904 905 If unsure, say N. 906 907config DEBUG_VM_PGFLAGS 908 bool "Debug page-flags operations" 909 depends on DEBUG_VM 910 help 911 Enables extra validation on page flags operations. 912 913 If unsure, say N. 914 915config DEBUG_VM_PGTABLE 916 bool "Debug arch page table for semantics compliance" 917 depends on MMU 918 depends on ARCH_HAS_DEBUG_VM_PGTABLE 919 default y if DEBUG_VM 920 help 921 This option provides a debug method which can be used to test 922 architecture page table helper functions on various platforms in 923 verifying if they comply with expected generic MM semantics. This 924 will help architecture code in making sure that any changes or 925 new additions of these helpers still conform to expected 926 semantics of the generic MM. Platforms will have to opt in for 927 this through ARCH_HAS_DEBUG_VM_PGTABLE. 928 929 If unsure, say N. 930 931config ARCH_HAS_DEBUG_VIRTUAL 932 bool 933 934config DEBUG_VIRTUAL 935 bool "Debug VM translations" 936 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 937 help 938 Enable some costly sanity checks in virtual to page code. This can 939 catch mistakes with virt_to_page() and friends. 940 941 If unsure, say N. 942 943config DEBUG_NOMMU_REGIONS 944 bool "Debug the global anon/private NOMMU mapping region tree" 945 depends on DEBUG_KERNEL && !MMU 946 help 947 This option causes the global tree of anonymous and private mapping 948 regions to be regularly checked for invalid topology. 949 950config DEBUG_MEMORY_INIT 951 bool "Debug memory initialisation" if EXPERT 952 default !EXPERT 953 help 954 Enable this for additional checks during memory initialisation. 955 The sanity checks verify aspects of the VM such as the memory model 956 and other information provided by the architecture. Verbose 957 information will be printed at KERN_DEBUG loglevel depending 958 on the mminit_loglevel= command-line option. 959 960 If unsure, say Y 961 962config MEMORY_NOTIFIER_ERROR_INJECT 963 tristate "Memory hotplug notifier error injection module" 964 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 965 help 966 This option provides the ability to inject artificial errors to 967 memory hotplug notifier chain callbacks. It is controlled through 968 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 969 970 If the notifier call chain should be failed with some events 971 notified, write the error code to "actions/<notifier event>/error". 972 973 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 974 975 # cd /sys/kernel/debug/notifier-error-inject/memory 976 # echo -12 > actions/MEM_GOING_OFFLINE/error 977 # echo offline > /sys/devices/system/memory/memoryXXX/state 978 bash: echo: write error: Cannot allocate memory 979 980 To compile this code as a module, choose M here: the module will 981 be called memory-notifier-error-inject. 982 983 If unsure, say N. 984 985config DEBUG_PER_CPU_MAPS 986 bool "Debug access to per_cpu maps" 987 depends on DEBUG_KERNEL 988 depends on SMP 989 help 990 Say Y to verify that the per_cpu map being accessed has 991 been set up. This adds a fair amount of code to kernel memory 992 and decreases performance. 993 994 Say N if unsure. 995 996config DEBUG_KMAP_LOCAL 997 bool "Debug kmap_local temporary mappings" 998 depends on DEBUG_KERNEL && KMAP_LOCAL 999 help 1000 This option enables additional error checking for the kmap_local 1001 infrastructure. Disable for production use. 1002 1003config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 1004 bool 1005 1006config DEBUG_KMAP_LOCAL_FORCE_MAP 1007 bool "Enforce kmap_local temporary mappings" 1008 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 1009 select KMAP_LOCAL 1010 select DEBUG_KMAP_LOCAL 1011 help 1012 This option enforces temporary mappings through the kmap_local 1013 mechanism for non-highmem pages and on non-highmem systems. 1014 Disable this for production systems! 1015 1016config DEBUG_HIGHMEM 1017 bool "Highmem debugging" 1018 depends on DEBUG_KERNEL && HIGHMEM 1019 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 1020 select DEBUG_KMAP_LOCAL 1021 help 1022 This option enables additional error checking for high memory 1023 systems. Disable for production systems. 1024 1025config HAVE_DEBUG_STACKOVERFLOW 1026 bool 1027 1028config DEBUG_STACKOVERFLOW 1029 bool "Check for stack overflows" 1030 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 1031 help 1032 Say Y here if you want to check for overflows of kernel, IRQ 1033 and exception stacks (if your architecture uses them). This 1034 option will show detailed messages if free stack space drops 1035 below a certain limit. 1036 1037 These kinds of bugs usually occur when call-chains in the 1038 kernel get too deep, especially when interrupts are 1039 involved. 1040 1041 Use this in cases where you see apparently random memory 1042 corruption, especially if it appears in 'struct thread_info' 1043 1044 If in doubt, say "N". 1045 1046config CODE_TAGGING 1047 bool 1048 select KALLSYMS 1049 1050config MEM_ALLOC_PROFILING 1051 bool "Enable memory allocation profiling" 1052 default n 1053 depends on MMU 1054 depends on PROC_FS 1055 depends on !DEBUG_FORCE_WEAK_PER_CPU 1056 select CODE_TAGGING 1057 select PAGE_EXTENSION 1058 select SLAB_OBJ_EXT 1059 help 1060 Track allocation source code and record total allocation size 1061 initiated at that code location. The mechanism can be used to track 1062 memory leaks with a low performance and memory impact. 1063 1064config MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT 1065 bool "Enable memory allocation profiling by default" 1066 default y 1067 depends on MEM_ALLOC_PROFILING 1068 1069config MEM_ALLOC_PROFILING_DEBUG 1070 bool "Memory allocation profiler debugging" 1071 default n 1072 depends on MEM_ALLOC_PROFILING 1073 select MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT 1074 help 1075 Adds warnings with helpful error messages for memory allocation 1076 profiling. 1077 1078source "lib/Kconfig.kasan" 1079source "lib/Kconfig.kfence" 1080source "lib/Kconfig.kmsan" 1081 1082endmenu # "Memory Debugging" 1083 1084config DEBUG_SHIRQ 1085 bool "Debug shared IRQ handlers" 1086 depends on DEBUG_KERNEL 1087 help 1088 Enable this to generate a spurious interrupt just before a shared 1089 interrupt handler is deregistered (generating one when registering 1090 is currently disabled). Drivers need to handle this correctly. Some 1091 don't and need to be caught. 1092 1093menu "Debug Oops, Lockups and Hangs" 1094 1095config PANIC_ON_OOPS 1096 bool "Panic on Oops" 1097 help 1098 Say Y here to enable the kernel to panic when it oopses. This 1099 has the same effect as setting oops=panic on the kernel command 1100 line. 1101 1102 This feature is useful to ensure that the kernel does not do 1103 anything erroneous after an oops which could result in data 1104 corruption or other issues. 1105 1106 Say N if unsure. 1107 1108config PANIC_TIMEOUT 1109 int "panic timeout" 1110 default 0 1111 help 1112 Set the timeout value (in seconds) until a reboot occurs when 1113 the kernel panics. If n = 0, then we wait forever. A timeout 1114 value n > 0 will wait n seconds before rebooting, while a timeout 1115 value n < 0 will reboot immediately. This setting can be overridden 1116 with the kernel command line option panic=, and from userspace via 1117 /proc/sys/kernel/panic. 1118 1119config LOCKUP_DETECTOR 1120 bool 1121 1122config SOFTLOCKUP_DETECTOR 1123 bool "Detect Soft Lockups" 1124 depends on DEBUG_KERNEL && !S390 1125 select LOCKUP_DETECTOR 1126 help 1127 Say Y here to enable the kernel to act as a watchdog to detect 1128 soft lockups. 1129 1130 Softlockups are bugs that cause the kernel to loop in kernel 1131 mode for more than 20 seconds, without giving other tasks a 1132 chance to run. The current stack trace is displayed upon 1133 detection and the system will stay locked up. 1134 1135config SOFTLOCKUP_DETECTOR_INTR_STORM 1136 bool "Detect Interrupt Storm in Soft Lockups" 1137 depends on SOFTLOCKUP_DETECTOR && IRQ_TIME_ACCOUNTING 1138 select GENERIC_IRQ_STAT_SNAPSHOT 1139 default y if NR_CPUS <= 128 1140 help 1141 Say Y here to enable the kernel to detect interrupt storm 1142 during "soft lockups". 1143 1144 "soft lockups" can be caused by a variety of reasons. If one is 1145 caused by an interrupt storm, then the storming interrupts will not 1146 be on the callstack. To detect this case, it is necessary to report 1147 the CPU stats and the interrupt counts during the "soft lockups". 1148 1149config BOOTPARAM_SOFTLOCKUP_PANIC 1150 int "Panic (Reboot) On Soft Lockups" 1151 depends on SOFTLOCKUP_DETECTOR 1152 default 0 1153 help 1154 Set to a non-zero value N to enable the kernel to panic on "soft 1155 lockups", which are bugs that cause the kernel to loop in kernel 1156 mode for more than (N * 20 seconds) (configurable using the 1157 watchdog_thresh sysctl), without giving other tasks a chance to run. 1158 1159 The panic can be used in combination with panic_timeout, 1160 to cause the system to reboot automatically after a 1161 lockup has been detected. This feature is useful for 1162 high-availability systems that have uptime guarantees and 1163 where a lockup must be resolved ASAP. 1164 1165 Say 0 if unsure. 1166 1167config HAVE_HARDLOCKUP_DETECTOR_BUDDY 1168 bool 1169 depends on SMP 1170 default y 1171 1172# 1173# Global switch whether to build a hardlockup detector at all. It is available 1174# only when the architecture supports at least one implementation. There are 1175# two exceptions. The hardlockup detector is never enabled on: 1176# 1177# s390: it reported many false positives there 1178# 1179# sparc64: has a custom implementation which is not using the common 1180# hardlockup command line options and sysctl interface. 1181# 1182config HARDLOCKUP_DETECTOR 1183 bool "Detect Hard Lockups" 1184 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64 1185 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH 1186 imply HARDLOCKUP_DETECTOR_PERF 1187 imply HARDLOCKUP_DETECTOR_BUDDY 1188 imply HARDLOCKUP_DETECTOR_ARCH 1189 select LOCKUP_DETECTOR 1190 1191 help 1192 Say Y here to enable the kernel to act as a watchdog to detect 1193 hard lockups. 1194 1195 Hardlockups are bugs that cause the CPU to loop in kernel mode 1196 for more than 10 seconds, without letting other interrupts have a 1197 chance to run. The current stack trace is displayed upon detection 1198 and the system will stay locked up. 1199 1200# 1201# Note that arch-specific variants are always preferred. 1202# 1203config HARDLOCKUP_DETECTOR_PREFER_BUDDY 1204 bool "Prefer the buddy CPU hardlockup detector" 1205 depends on HARDLOCKUP_DETECTOR 1206 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY 1207 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1208 help 1209 Say Y here to prefer the buddy hardlockup detector over the perf one. 1210 1211 With the buddy detector, each CPU uses its softlockup hrtimer 1212 to check that the next CPU is processing hrtimer interrupts by 1213 verifying that a counter is increasing. 1214 1215 This hardlockup detector is useful on systems that don't have 1216 an arch-specific hardlockup detector or if resources needed 1217 for the hardlockup detector are better used for other things. 1218 1219config HARDLOCKUP_DETECTOR_PERF 1220 bool 1221 depends on HARDLOCKUP_DETECTOR 1222 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY 1223 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1224 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1225 1226config HARDLOCKUP_DETECTOR_BUDDY 1227 bool 1228 depends on HARDLOCKUP_DETECTOR 1229 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY 1230 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY 1231 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1232 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1233 1234config HARDLOCKUP_DETECTOR_ARCH 1235 bool 1236 depends on HARDLOCKUP_DETECTOR 1237 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH 1238 help 1239 The arch-specific implementation of the hardlockup detector will 1240 be used. 1241 1242# 1243# Both the "perf" and "buddy" hardlockup detectors count hrtimer 1244# interrupts. This config enables functions managing this common code. 1245# 1246config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1247 bool 1248 select SOFTLOCKUP_DETECTOR 1249 1250# 1251# Enables a timestamp based low pass filter to compensate for perf based 1252# hard lockup detection which runs too fast due to turbo modes. 1253# 1254config HARDLOCKUP_CHECK_TIMESTAMP 1255 bool 1256 1257config BOOTPARAM_HARDLOCKUP_PANIC 1258 bool "Panic (Reboot) On Hard Lockups" 1259 depends on HARDLOCKUP_DETECTOR 1260 help 1261 Say Y here to enable the kernel to panic on "hard lockups", 1262 which are bugs that cause the kernel to loop in kernel 1263 mode with interrupts disabled for more than 10 seconds (configurable 1264 using the watchdog_thresh sysctl). 1265 1266 Say N if unsure. 1267 1268config DETECT_HUNG_TASK 1269 bool "Detect Hung Tasks" 1270 depends on DEBUG_KERNEL 1271 default SOFTLOCKUP_DETECTOR 1272 help 1273 Say Y here to enable the kernel to detect "hung tasks", 1274 which are bugs that cause the task to be stuck in 1275 uninterruptible "D" state indefinitely. 1276 1277 When a hung task is detected, the kernel will print the 1278 current stack trace (which you should report), but the 1279 task will stay in uninterruptible state. If lockdep is 1280 enabled then all held locks will also be reported. This 1281 feature has negligible overhead. 1282 1283config DEFAULT_HUNG_TASK_TIMEOUT 1284 int "Default timeout for hung task detection (in seconds)" 1285 depends on DETECT_HUNG_TASK 1286 default 120 1287 help 1288 This option controls the default timeout (in seconds) used 1289 to determine when a task has become non-responsive and should 1290 be considered hung. 1291 1292 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1293 sysctl or by writing a value to 1294 /proc/sys/kernel/hung_task_timeout_secs. 1295 1296 A timeout of 0 disables the check. The default is two minutes. 1297 Keeping the default should be fine in most cases. 1298 1299config BOOTPARAM_HUNG_TASK_PANIC 1300 int "Number of hung tasks to trigger kernel panic" 1301 depends on DETECT_HUNG_TASK 1302 default 0 1303 help 1304 When set to a non-zero value, a kernel panic will be triggered 1305 if the number of hung tasks found during a single scan reaches 1306 this value. 1307 1308 The panic can be used in combination with panic_timeout, 1309 to cause the system to reboot automatically after a 1310 hung task has been detected. This feature is useful for 1311 high-availability systems that have uptime guarantees and 1312 where a hung tasks must be resolved ASAP. 1313 1314 Say 0 if unsure. 1315 1316config DETECT_HUNG_TASK_BLOCKER 1317 bool "Dump Hung Tasks Blocker" 1318 depends on DETECT_HUNG_TASK 1319 depends on !PREEMPT_RT 1320 default y 1321 help 1322 Say Y here to show the blocker task's stacktrace who acquires 1323 the mutex lock which "hung tasks" are waiting. 1324 This will add overhead a bit but shows suspicious tasks and 1325 call trace if it comes from waiting a mutex. 1326 1327config WQ_WATCHDOG 1328 bool "Detect Workqueue Stalls" 1329 depends on DEBUG_KERNEL 1330 help 1331 Say Y here to enable stall detection on workqueues. If a 1332 worker pool doesn't make forward progress on a pending work 1333 item for over a given amount of time, 30s by default, a 1334 warning message is printed along with dump of workqueue 1335 state. This can be configured through kernel parameter 1336 "workqueue.watchdog_thresh" and its sysfs counterpart. 1337 1338config BOOTPARAM_WQ_STALL_PANIC 1339 int "Panic on Nth workqueue stall" 1340 default 0 1341 range 0 100 1342 depends on WQ_WATCHDOG 1343 help 1344 Set the number of workqueue stalls to trigger a kernel panic. 1345 A workqueue stall occurs when a worker pool doesn't make forward 1346 progress on a pending work item for over 30 seconds (configurable 1347 using the workqueue.watchdog_thresh parameter). 1348 1349 If n = 0, the kernel will not panic on stall. If n > 0, the kernel 1350 will panic after n stall warnings. 1351 1352 The panic can be used in combination with panic_timeout, 1353 to cause the system to reboot automatically after a 1354 stall has been detected. This feature is useful for 1355 high-availability systems that have uptime guarantees and 1356 where a stall must be resolved ASAP. 1357 1358 This setting can be overridden at runtime via the 1359 workqueue.panic_on_stall kernel parameter. 1360 1361config WQ_CPU_INTENSIVE_REPORT 1362 bool "Report per-cpu work items which hog CPU for too long" 1363 depends on DEBUG_KERNEL 1364 help 1365 Say Y here to enable reporting of concurrency-managed per-cpu work 1366 items that hog CPUs for longer than 1367 workqueue.cpu_intensive_thresh_us. Workqueue automatically 1368 detects and excludes them from concurrency management to prevent 1369 them from stalling other per-cpu work items. Occassional 1370 triggering may not necessarily indicate a problem. Repeated 1371 triggering likely indicates that the work item should be switched 1372 to use an unbound workqueue. 1373 1374config TEST_LOCKUP 1375 tristate "Test module to generate lockups" 1376 depends on m 1377 help 1378 This builds the "test_lockup" module that helps to make sure 1379 that watchdogs and lockup detectors are working properly. 1380 1381 Depending on module parameters it could emulate soft or hard 1382 lockup, "hung task", or locking arbitrary lock for a long time. 1383 Also it could generate series of lockups with cooling-down periods. 1384 1385 If unsure, say N. 1386 1387endmenu # "Debug lockups and hangs" 1388 1389menu "Scheduler Debugging" 1390 1391config SCHED_INFO 1392 bool 1393 default n 1394 1395config SCHEDSTATS 1396 bool "Collect scheduler statistics" 1397 depends on PROC_FS 1398 select SCHED_INFO 1399 help 1400 If you say Y here, additional code will be inserted into the 1401 scheduler and related routines to collect statistics about 1402 scheduler behavior and provide them in /proc/schedstat. These 1403 stats may be useful for both tuning and debugging the scheduler 1404 If you aren't debugging the scheduler or trying to tune a specific 1405 application, you can say N to avoid the very slight overhead 1406 this adds. 1407 1408endmenu 1409 1410config DEBUG_PREEMPT 1411 bool "Debug preemptible kernel" 1412 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1413 help 1414 If you say Y here then the kernel will use a debug variant of the 1415 commonly used smp_processor_id() function and will print warnings 1416 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1417 will detect preemption count underflows. 1418 1419 This option has potential to introduce high runtime overhead, 1420 depending on workload as it triggers debugging routines for each 1421 this_cpu operation. It should only be used for debugging purposes. 1422 1423config DEBUG_ATOMIC 1424 bool "Debug atomic variables" 1425 depends on DEBUG_KERNEL 1426 help 1427 If you say Y here then the kernel will add a runtime alignment check 1428 to atomic accesses. Useful for architectures that do not have trap on 1429 mis-aligned access. 1430 1431 This option has potentially significant overhead. 1432 1433config DEBUG_ATOMIC_LARGEST_ALIGN 1434 bool "Check alignment only up to __aligned_largest" 1435 depends on DEBUG_ATOMIC 1436 help 1437 If you say Y here then the check for natural alignment of 1438 atomic accesses will be constrained to the compiler's largest 1439 alignment for scalar types. 1440 1441menu "Lock Debugging (spinlocks, mutexes, etc...)" 1442 1443config LOCK_DEBUGGING_SUPPORT 1444 bool 1445 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1446 default y 1447 1448config PROVE_LOCKING 1449 bool "Lock debugging: prove locking correctness" 1450 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1451 select LOCKDEP 1452 select DEBUG_SPINLOCK 1453 select DEBUG_MUTEXES if !PREEMPT_RT 1454 select DEBUG_RT_MUTEXES if RT_MUTEXES 1455 select DEBUG_RWSEMS if !PREEMPT_RT 1456 select DEBUG_WW_MUTEX_SLOWPATH 1457 select DEBUG_LOCK_ALLOC 1458 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1459 select TRACE_IRQFLAGS 1460 default n 1461 help 1462 This feature enables the kernel to prove that all locking 1463 that occurs in the kernel runtime is mathematically 1464 correct: that under no circumstance could an arbitrary (and 1465 not yet triggered) combination of observed locking 1466 sequences (on an arbitrary number of CPUs, running an 1467 arbitrary number of tasks and interrupt contexts) cause a 1468 deadlock. 1469 1470 In short, this feature enables the kernel to report locking 1471 related deadlocks before they actually occur. 1472 1473 The proof does not depend on how hard and complex a 1474 deadlock scenario would be to trigger: how many 1475 participant CPUs, tasks and irq-contexts would be needed 1476 for it to trigger. The proof also does not depend on 1477 timing: if a race and a resulting deadlock is possible 1478 theoretically (no matter how unlikely the race scenario 1479 is), it will be proven so and will immediately be 1480 reported by the kernel (once the event is observed that 1481 makes the deadlock theoretically possible). 1482 1483 If a deadlock is impossible (i.e. the locking rules, as 1484 observed by the kernel, are mathematically correct), the 1485 kernel reports nothing. 1486 1487 NOTE: this feature can also be enabled for rwlocks, mutexes 1488 and rwsems - in which case all dependencies between these 1489 different locking variants are observed and mapped too, and 1490 the proof of observed correctness is also maintained for an 1491 arbitrary combination of these separate locking variants. 1492 1493 For more details, see Documentation/locking/lockdep-design.rst. 1494 1495config PROVE_RAW_LOCK_NESTING 1496 bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT 1497 depends on PROVE_LOCKING 1498 default y if ARCH_SUPPORTS_RT 1499 help 1500 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1501 that the lock nesting rules for PREEMPT_RT enabled kernels are 1502 not violated. 1503 1504config LOCK_STAT 1505 bool "Lock usage statistics" 1506 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1507 select LOCKDEP 1508 select DEBUG_SPINLOCK 1509 select DEBUG_MUTEXES if !PREEMPT_RT 1510 select DEBUG_RT_MUTEXES if RT_MUTEXES 1511 select DEBUG_LOCK_ALLOC 1512 default n 1513 help 1514 This feature enables tracking lock contention points 1515 1516 For more details, see Documentation/locking/lockstat.rst 1517 1518 This also enables lock events required by "perf lock", 1519 subcommand of perf. 1520 If you want to use "perf lock", you also need to turn on 1521 CONFIG_EVENT_TRACING. 1522 1523 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1524 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1525 1526config DEBUG_RT_MUTEXES 1527 bool "RT Mutex debugging, deadlock detection" 1528 depends on DEBUG_KERNEL && RT_MUTEXES 1529 help 1530 This allows rt mutex semantics violations and rt mutex related 1531 deadlocks (lockups) to be detected and reported automatically. 1532 1533config DEBUG_SPINLOCK 1534 bool "Spinlock and rw-lock debugging: basic checks" 1535 depends on DEBUG_KERNEL 1536 select UNINLINE_SPIN_UNLOCK 1537 help 1538 Say Y here and build SMP to catch missing spinlock initialization 1539 and certain other kinds of spinlock errors commonly made. This is 1540 best used in conjunction with the NMI watchdog so that spinlock 1541 deadlocks are also debuggable. 1542 1543config DEBUG_MUTEXES 1544 bool "Mutex debugging: basic checks" 1545 depends on DEBUG_KERNEL && !PREEMPT_RT 1546 help 1547 This feature allows mutex semantics violations to be detected and 1548 reported. 1549 1550config DEBUG_WW_MUTEX_SLOWPATH 1551 bool "Wait/wound mutex debugging: Slowpath testing" 1552 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1553 select DEBUG_LOCK_ALLOC 1554 select DEBUG_SPINLOCK 1555 select DEBUG_MUTEXES if !PREEMPT_RT 1556 select DEBUG_RT_MUTEXES if PREEMPT_RT 1557 help 1558 This feature enables slowpath testing for w/w mutex users by 1559 injecting additional -EDEADLK wound/backoff cases. Together with 1560 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1561 will test all possible w/w mutex interface abuse with the 1562 exception of simply not acquiring all the required locks. 1563 Note that this feature can introduce significant overhead, so 1564 it really should not be enabled in a production or distro kernel, 1565 even a debug kernel. If you are a driver writer, enable it. If 1566 you are a distro, do not. 1567 1568config DEBUG_RWSEMS 1569 bool "RW Semaphore debugging: basic checks" 1570 depends on DEBUG_KERNEL && !PREEMPT_RT 1571 help 1572 This debugging feature allows mismatched rw semaphore locks 1573 and unlocks to be detected and reported. 1574 1575config DEBUG_LOCK_ALLOC 1576 bool "Lock debugging: detect incorrect freeing of live locks" 1577 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1578 select DEBUG_SPINLOCK 1579 select DEBUG_MUTEXES if !PREEMPT_RT 1580 select DEBUG_RT_MUTEXES if RT_MUTEXES 1581 select LOCKDEP 1582 help 1583 This feature will check whether any held lock (spinlock, rwlock, 1584 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1585 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1586 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1587 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1588 held during task exit. 1589 1590config LOCKDEP 1591 bool 1592 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1593 select STACKTRACE 1594 select KALLSYMS 1595 select KALLSYMS_ALL 1596 1597config LOCKDEP_SMALL 1598 bool 1599 1600config LOCKDEP_BITS 1601 int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)" 1602 depends on LOCKDEP && !LOCKDEP_SMALL 1603 range 10 24 1604 default 15 1605 help 1606 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1607 1608config LOCKDEP_CHAINS_BITS 1609 int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)" 1610 depends on LOCKDEP && !LOCKDEP_SMALL 1611 range 10 21 1612 default 16 1613 help 1614 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1615 1616config LOCKDEP_STACK_TRACE_BITS 1617 int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)" 1618 depends on LOCKDEP && !LOCKDEP_SMALL 1619 range 10 26 1620 default 19 1621 help 1622 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1623 1624config LOCKDEP_STACK_TRACE_HASH_BITS 1625 int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)" 1626 depends on LOCKDEP && !LOCKDEP_SMALL 1627 range 10 26 1628 default 14 1629 help 1630 Try increasing this value if you need large STACK_TRACE_HASH_SIZE. 1631 1632config LOCKDEP_CIRCULAR_QUEUE_BITS 1633 int "Size for elements in circular_queue struct (as Nth power of 2)" 1634 depends on LOCKDEP 1635 range 10 26 1636 default 12 1637 help 1638 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1639 1640config DEBUG_LOCKDEP 1641 bool "Lock dependency engine debugging" 1642 depends on DEBUG_KERNEL && LOCKDEP 1643 select DEBUG_IRQFLAGS 1644 help 1645 If you say Y here, the lock dependency engine will do 1646 additional runtime checks to debug itself, at the price 1647 of more runtime overhead. 1648 1649config DEBUG_ATOMIC_SLEEP 1650 bool "Sleep inside atomic section checking" 1651 select PREEMPT_COUNT 1652 depends on DEBUG_KERNEL 1653 depends on !ARCH_NO_PREEMPT 1654 help 1655 If you say Y here, various routines which may sleep will become very 1656 noisy if they are called inside atomic sections: when a spinlock is 1657 held, inside an rcu read side critical section, inside preempt disabled 1658 sections, inside an interrupt, etc... 1659 1660config DEBUG_LOCKING_API_SELFTESTS 1661 bool "Locking API boot-time self-tests" 1662 depends on DEBUG_KERNEL 1663 help 1664 Say Y here if you want the kernel to run a short self-test during 1665 bootup. The self-test checks whether common types of locking bugs 1666 are detected by debugging mechanisms or not. (if you disable 1667 lock debugging then those bugs won't be detected of course.) 1668 The following locking APIs are covered: spinlocks, rwlocks, 1669 mutexes and rwsems. 1670 1671config LOCK_TORTURE_TEST 1672 tristate "torture tests for locking" 1673 depends on DEBUG_KERNEL 1674 select TORTURE_TEST 1675 help 1676 This option provides a kernel module that runs torture tests 1677 on kernel locking primitives. The kernel module may be built 1678 after the fact on the running kernel to be tested, if desired. 1679 1680 Say Y here if you want kernel locking-primitive torture tests 1681 to be built into the kernel. 1682 Say M if you want these torture tests to build as a module. 1683 Say N if you are unsure. 1684 1685config WW_MUTEX_SELFTEST 1686 tristate "Wait/wound mutex selftests" 1687 help 1688 This option provides a kernel module that runs tests on the 1689 on the struct ww_mutex locking API. 1690 1691 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1692 with this test harness. 1693 1694 Say M if you want these self tests to build as a module. 1695 Say N if you are unsure. 1696 1697config SCF_TORTURE_TEST 1698 tristate "torture tests for smp_call_function*()" 1699 depends on DEBUG_KERNEL 1700 select TORTURE_TEST 1701 help 1702 This option provides a kernel module that runs torture tests 1703 on the smp_call_function() family of primitives. The kernel 1704 module may be built after the fact on the running kernel to 1705 be tested, if desired. 1706 1707config CSD_LOCK_WAIT_DEBUG 1708 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1709 depends on DEBUG_KERNEL 1710 depends on SMP 1711 depends on 64BIT 1712 default n 1713 help 1714 This option enables debug prints when CPUs are slow to respond 1715 to the smp_call_function*() IPI wrappers. These debug prints 1716 include the IPI handler function currently executing (if any) 1717 and relevant stack traces. 1718 1719config CSD_LOCK_WAIT_DEBUG_DEFAULT 1720 bool "Default csd_lock_wait() debugging on at boot time" 1721 depends on CSD_LOCK_WAIT_DEBUG 1722 depends on 64BIT 1723 default n 1724 help 1725 This option causes the csdlock_debug= kernel boot parameter to 1726 default to 1 (basic debugging) instead of 0 (no debugging). 1727 1728endmenu # lock debugging 1729 1730config TRACE_IRQFLAGS 1731 depends on TRACE_IRQFLAGS_SUPPORT 1732 bool 1733 help 1734 Enables hooks to interrupt enabling and disabling for 1735 either tracing or lock debugging. 1736 1737config TRACE_IRQFLAGS_NMI 1738 def_bool y 1739 depends on TRACE_IRQFLAGS 1740 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1741 1742config NMI_CHECK_CPU 1743 bool "Debugging for CPUs failing to respond to backtrace requests" 1744 depends on DEBUG_KERNEL 1745 depends on X86 1746 default n 1747 help 1748 Enables debug prints when a CPU fails to respond to a given 1749 backtrace NMI. These prints provide some reasons why a CPU 1750 might legitimately be failing to respond, for example, if it 1751 is offline of if ignore_nmis is set. 1752 1753config DEBUG_IRQFLAGS 1754 bool "Debug IRQ flag manipulation" 1755 help 1756 Enables checks for potentially unsafe enabling or disabling of 1757 interrupts, such as calling raw_local_irq_restore() when interrupts 1758 are enabled. 1759 1760config STACKTRACE 1761 bool "Stack backtrace support" 1762 depends on STACKTRACE_SUPPORT 1763 help 1764 This option causes the kernel to create a /proc/pid/stack for 1765 every process, showing its current stack trace. 1766 It is also used by various kernel debugging features that require 1767 stack trace generation. 1768 1769config DEBUG_KOBJECT 1770 bool "kobject debugging" 1771 depends on DEBUG_KERNEL 1772 help 1773 If you say Y here, some extra kobject debugging messages will be sent 1774 to the syslog. 1775 1776config DEBUG_KOBJECT_RELEASE 1777 bool "kobject release debugging" 1778 depends on DEBUG_OBJECTS_TIMERS 1779 help 1780 kobjects are reference counted objects. This means that their 1781 last reference count put is not predictable, and the kobject can 1782 live on past the point at which a driver decides to drop its 1783 initial reference to the kobject gained on allocation. An 1784 example of this would be a struct device which has just been 1785 unregistered. 1786 1787 However, some buggy drivers assume that after such an operation, 1788 the memory backing the kobject can be immediately freed. This 1789 goes completely against the principles of a refcounted object. 1790 1791 If you say Y here, the kernel will delay the release of kobjects 1792 on the last reference count to improve the visibility of this 1793 kind of kobject release bug. 1794 1795config HAVE_DEBUG_BUGVERBOSE 1796 bool 1797 1798menu "Debug kernel data structures" 1799 1800config DEBUG_LIST 1801 bool "Debug linked list manipulation" 1802 depends on DEBUG_KERNEL 1803 select LIST_HARDENED 1804 help 1805 Enable this to turn on extended checks in the linked-list walking 1806 routines. 1807 1808 This option trades better quality error reports for performance, and 1809 is more suitable for kernel debugging. If you care about performance, 1810 you should only enable CONFIG_LIST_HARDENED instead. 1811 1812 If unsure, say N. 1813 1814config DEBUG_PLIST 1815 bool "Debug priority linked list manipulation" 1816 depends on DEBUG_KERNEL 1817 help 1818 Enable this to turn on extended checks in the priority-ordered 1819 linked-list (plist) walking routines. This checks the entire 1820 list multiple times during each manipulation. 1821 1822 If unsure, say N. 1823 1824config DEBUG_SG 1825 bool "Debug SG table operations" 1826 depends on DEBUG_KERNEL 1827 help 1828 Enable this to turn on checks on scatter-gather tables. This can 1829 help find problems with drivers that do not properly initialize 1830 their sg tables. 1831 1832 If unsure, say N. 1833 1834config DEBUG_NOTIFIERS 1835 bool "Debug notifier call chains" 1836 depends on DEBUG_KERNEL 1837 help 1838 Enable this to turn on sanity checking for notifier call chains. 1839 This is most useful for kernel developers to make sure that 1840 modules properly unregister themselves from notifier chains. 1841 This is a relatively cheap check but if you care about maximum 1842 performance, say N. 1843 1844config DEBUG_CLOSURES 1845 bool "Debug closures (bcache async widgits)" 1846 depends on CLOSURES 1847 select DEBUG_FS 1848 help 1849 Keeps all active closures in a linked list and provides a debugfs 1850 interface to list them, which makes it possible to see asynchronous 1851 operations that get stuck. 1852 1853config DEBUG_MAPLE_TREE 1854 bool "Debug maple trees" 1855 depends on DEBUG_KERNEL 1856 help 1857 Enable maple tree debugging information and extra validations. 1858 1859 If unsure, say N. 1860 1861endmenu 1862 1863source "kernel/rcu/Kconfig.debug" 1864 1865config DEBUG_WQ_FORCE_RR_CPU 1866 bool "Force round-robin CPU selection for unbound work items" 1867 depends on DEBUG_KERNEL 1868 default n 1869 help 1870 Workqueue used to implicitly guarantee that work items queued 1871 without explicit CPU specified are put on the local CPU. This 1872 guarantee is no longer true and while local CPU is still 1873 preferred work items may be put on foreign CPUs. Kernel 1874 parameter "workqueue.debug_force_rr_cpu" is added to force 1875 round-robin CPU selection to flush out usages which depend on the 1876 now broken guarantee. This config option enables the debug 1877 feature by default. When enabled, memory and cache locality will 1878 be impacted. 1879 1880config CPU_HOTPLUG_STATE_CONTROL 1881 bool "Enable CPU hotplug state control" 1882 depends on DEBUG_KERNEL 1883 depends on HOTPLUG_CPU 1884 default n 1885 help 1886 Allows to write steps between "offline" and "online" to the CPUs 1887 sysfs target file so states can be stepped granular. This is a debug 1888 option for now as the hotplug machinery cannot be stopped and 1889 restarted at arbitrary points yet. 1890 1891 Say N if your are unsure. 1892 1893config LATENCYTOP 1894 bool "Latency measuring infrastructure" 1895 depends on DEBUG_KERNEL 1896 depends on STACKTRACE_SUPPORT 1897 depends on PROC_FS 1898 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1899 select KALLSYMS 1900 select KALLSYMS_ALL 1901 select STACKTRACE 1902 select SCHEDSTATS 1903 help 1904 Enable this option if you want to use the LatencyTOP tool 1905 to find out which userspace is blocking on what kernel operations. 1906 1907config DEBUG_CGROUP_REF 1908 bool "Disable inlining of cgroup css reference count functions" 1909 depends on DEBUG_KERNEL 1910 depends on CGROUPS 1911 depends on KPROBES 1912 default n 1913 help 1914 Force cgroup css reference count functions to not be inlined so 1915 that they can be kprobed for debugging. 1916 1917source "kernel/trace/Kconfig" 1918 1919config PROVIDE_OHCI1394_DMA_INIT 1920 bool "Remote debugging over FireWire early on boot" 1921 depends on PCI && X86 1922 help 1923 If you want to debug problems which hang or crash the kernel early 1924 on boot and the crashing machine has a FireWire port, you can use 1925 this feature to remotely access the memory of the crashed machine 1926 over FireWire. This employs remote DMA as part of the OHCI1394 1927 specification which is now the standard for FireWire controllers. 1928 1929 With remote DMA, you can monitor the printk buffer remotely using 1930 firescope and access all memory below 4GB using fireproxy from gdb. 1931 Even controlling a kernel debugger is possible using remote DMA. 1932 1933 Usage: 1934 1935 If ohci1394_dma=early is used as boot parameter, it will initialize 1936 all OHCI1394 controllers which are found in the PCI config space. 1937 1938 As all changes to the FireWire bus such as enabling and disabling 1939 devices cause a bus reset and thereby disable remote DMA for all 1940 devices, be sure to have the cable plugged and FireWire enabled on 1941 the debugging host before booting the debug target for debugging. 1942 1943 This code (~1k) is freed after boot. By then, the firewire stack 1944 in charge of the OHCI-1394 controllers should be used instead. 1945 1946 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1947 1948source "samples/Kconfig" 1949 1950config ARCH_HAS_DEVMEM_IS_ALLOWED 1951 bool 1952 1953config STRICT_DEVMEM 1954 bool "Filter access to /dev/mem" 1955 depends on MMU && DEVMEM 1956 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1957 default y if PPC || X86 || ARM64 || S390 1958 help 1959 If this option is disabled, you allow userspace (root) access to all 1960 of memory, including kernel and userspace memory. Accidental 1961 access to this is obviously disastrous, but specific access can 1962 be used by people debugging the kernel. Note that with PAT support 1963 enabled, even in this case there are restrictions on /dev/mem 1964 use due to the cache aliasing requirements. 1965 1966 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1967 file only allows userspace access to PCI space and the BIOS code and 1968 data regions. This is sufficient for dosemu and X and all common 1969 users of /dev/mem. 1970 1971 If in doubt, say Y. 1972 1973config IO_STRICT_DEVMEM 1974 bool "Filter I/O access to /dev/mem" 1975 depends on STRICT_DEVMEM 1976 help 1977 If this option is disabled, you allow userspace (root) access to all 1978 io-memory regardless of whether a driver is actively using that 1979 range. Accidental access to this is obviously disastrous, but 1980 specific access can be used by people debugging kernel drivers. 1981 1982 If this option is switched on, the /dev/mem file only allows 1983 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1984 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1985 if the driver using a given range cannot be disabled. 1986 1987 If in doubt, say Y. 1988 1989menu "$(SRCARCH) Debugging" 1990 1991source "arch/$(SRCARCH)/Kconfig.debug" 1992 1993endmenu 1994 1995menu "Kernel Testing and Coverage" 1996 1997source "lib/kunit/Kconfig" 1998 1999config NOTIFIER_ERROR_INJECTION 2000 tristate "Notifier error injection" 2001 depends on DEBUG_KERNEL 2002 select DEBUG_FS 2003 help 2004 This option provides the ability to inject artificial errors to 2005 specified notifier chain callbacks. It is useful to test the error 2006 handling of notifier call chain failures. 2007 2008 Say N if unsure. 2009 2010config PM_NOTIFIER_ERROR_INJECT 2011 tristate "PM notifier error injection module" 2012 depends on PM && NOTIFIER_ERROR_INJECTION 2013 default m if PM_DEBUG 2014 help 2015 This option provides the ability to inject artificial errors to 2016 PM notifier chain callbacks. It is controlled through debugfs 2017 interface /sys/kernel/debug/notifier-error-inject/pm 2018 2019 If the notifier call chain should be failed with some events 2020 notified, write the error code to "actions/<notifier event>/error". 2021 2022 Example: Inject PM suspend error (-12 = -ENOMEM) 2023 2024 # cd /sys/kernel/debug/notifier-error-inject/pm/ 2025 # echo -12 > actions/PM_SUSPEND_PREPARE/error 2026 # echo mem > /sys/power/state 2027 bash: echo: write error: Cannot allocate memory 2028 2029 To compile this code as a module, choose M here: the module will 2030 be called pm-notifier-error-inject. 2031 2032 If unsure, say N. 2033 2034config OF_RECONFIG_NOTIFIER_ERROR_INJECT 2035 tristate "OF reconfig notifier error injection module" 2036 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 2037 help 2038 This option provides the ability to inject artificial errors to 2039 OF reconfig notifier chain callbacks. It is controlled 2040 through debugfs interface under 2041 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 2042 2043 If the notifier call chain should be failed with some events 2044 notified, write the error code to "actions/<notifier event>/error". 2045 2046 To compile this code as a module, choose M here: the module will 2047 be called of-reconfig-notifier-error-inject. 2048 2049 If unsure, say N. 2050 2051config NETDEV_NOTIFIER_ERROR_INJECT 2052 tristate "Netdev notifier error injection module" 2053 depends on NET && NOTIFIER_ERROR_INJECTION 2054 help 2055 This option provides the ability to inject artificial errors to 2056 netdevice notifier chain callbacks. It is controlled through debugfs 2057 interface /sys/kernel/debug/notifier-error-inject/netdev 2058 2059 If the notifier call chain should be failed with some events 2060 notified, write the error code to "actions/<notifier event>/error". 2061 2062 Example: Inject netdevice mtu change error (-22 = -EINVAL) 2063 2064 # cd /sys/kernel/debug/notifier-error-inject/netdev 2065 # echo -22 > actions/NETDEV_CHANGEMTU/error 2066 # ip link set eth0 mtu 1024 2067 RTNETLINK answers: Invalid argument 2068 2069 To compile this code as a module, choose M here: the module will 2070 be called netdev-notifier-error-inject. 2071 2072 If unsure, say N. 2073 2074config FUNCTION_ERROR_INJECTION 2075 bool "Fault-injections of functions" 2076 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 2077 help 2078 Add fault injections into various functions that are annotated with 2079 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 2080 value of these functions. This is useful to test error paths of code. 2081 2082 If unsure, say N 2083 2084config FAULT_INJECTION 2085 bool "Fault-injection framework" 2086 depends on DEBUG_KERNEL 2087 help 2088 Provide fault-injection framework. 2089 For more details, see Documentation/fault-injection/. 2090 2091config FAILSLAB 2092 bool "Fault-injection capability for kmalloc" 2093 depends on FAULT_INJECTION 2094 help 2095 Provide fault-injection capability for kmalloc. 2096 2097config FAIL_PAGE_ALLOC 2098 bool "Fault-injection capability for alloc_pages()" 2099 depends on FAULT_INJECTION 2100 help 2101 Provide fault-injection capability for alloc_pages(). 2102 2103config FAULT_INJECTION_USERCOPY 2104 bool "Fault injection capability for usercopy functions" 2105 depends on FAULT_INJECTION 2106 help 2107 Provides fault-injection capability to inject failures 2108 in usercopy functions (copy_from_user(), get_user(), ...). 2109 2110config FAIL_MAKE_REQUEST 2111 bool "Fault-injection capability for disk IO" 2112 depends on FAULT_INJECTION && BLOCK 2113 help 2114 Provide fault-injection capability for disk IO. 2115 2116config FAIL_IO_TIMEOUT 2117 bool "Fault-injection capability for faking disk interrupts" 2118 depends on FAULT_INJECTION && BLOCK 2119 help 2120 Provide fault-injection capability on end IO handling. This 2121 will make the block layer "forget" an interrupt as configured, 2122 thus exercising the error handling. 2123 2124 Only works with drivers that use the generic timeout handling, 2125 for others it won't do anything. 2126 2127config FAIL_FUTEX 2128 bool "Fault-injection capability for futexes" 2129 select DEBUG_FS 2130 depends on FAULT_INJECTION && FUTEX 2131 help 2132 Provide fault-injection capability for futexes. 2133 2134config FAULT_INJECTION_DEBUG_FS 2135 bool "Debugfs entries for fault-injection capabilities" 2136 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 2137 help 2138 Enable configuration of fault-injection capabilities via debugfs. 2139 2140config FAIL_FUNCTION 2141 bool "Fault-injection capability for functions" 2142 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 2143 help 2144 Provide function-based fault-injection capability. 2145 This will allow you to override a specific function with a return 2146 with given return value. As a result, function caller will see 2147 an error value and have to handle it. This is useful to test the 2148 error handling in various subsystems. 2149 2150config FAIL_MMC_REQUEST 2151 bool "Fault-injection capability for MMC IO" 2152 depends on FAULT_INJECTION_DEBUG_FS && MMC 2153 help 2154 Provide fault-injection capability for MMC IO. 2155 This will make the mmc core return data errors. This is 2156 useful to test the error handling in the mmc block device 2157 and to test how the mmc host driver handles retries from 2158 the block device. 2159 2160config FAIL_SUNRPC 2161 bool "Fault-injection capability for SunRPC" 2162 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2163 help 2164 Provide fault-injection capability for SunRPC and 2165 its consumers. 2166 2167config FAIL_SKB_REALLOC 2168 bool "Fault-injection capability forcing skb to reallocate" 2169 depends on FAULT_INJECTION_DEBUG_FS 2170 help 2171 Provide fault-injection capability that forces the skb to be 2172 reallocated, catching possible invalid pointers to the skb. 2173 2174 For more information, check 2175 Documentation/fault-injection/fault-injection.rst 2176 2177config FAULT_INJECTION_CONFIGFS 2178 bool "Configfs interface for fault-injection capabilities" 2179 depends on FAULT_INJECTION 2180 select CONFIGFS_FS 2181 help 2182 This option allows configfs-based drivers to dynamically configure 2183 fault-injection via configfs. Each parameter for driver-specific 2184 fault-injection can be made visible as a configfs attribute in a 2185 configfs group. 2186 2187 2188config FAULT_INJECTION_STACKTRACE_FILTER 2189 bool "stacktrace filter for fault-injection capabilities" 2190 depends on FAULT_INJECTION 2191 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT 2192 select STACKTRACE 2193 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2194 help 2195 Provide stacktrace filter for fault-injection capabilities 2196 2197config ARCH_HAS_KCOV 2198 bool 2199 help 2200 An architecture should select this when it can successfully 2201 build and run with CONFIG_KCOV. This typically requires 2202 disabling instrumentation for some early boot code. 2203 2204config KCOV 2205 bool "Code coverage for fuzzing" 2206 depends on ARCH_HAS_KCOV 2207 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2208 GCC_VERSION >= 120000 || CC_IS_CLANG 2209 select DEBUG_FS 2210 select OBJTOOL if HAVE_NOINSTR_HACK 2211 help 2212 KCOV exposes kernel code coverage information in a form suitable 2213 for coverage-guided fuzzing (randomized testing). 2214 2215 For more details, see Documentation/dev-tools/kcov.rst. 2216 2217config KCOV_ENABLE_COMPARISONS 2218 bool "Enable comparison operands collection by KCOV" 2219 depends on KCOV 2220 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2221 help 2222 KCOV also exposes operands of every comparison in the instrumented 2223 code along with operand sizes and PCs of the comparison instructions. 2224 These operands can be used by fuzzing engines to improve the quality 2225 of fuzzing coverage. 2226 2227config KCOV_INSTRUMENT_ALL 2228 bool "Instrument all code by default" 2229 depends on KCOV 2230 default y 2231 help 2232 If you are doing generic system call fuzzing (like e.g. syzkaller), 2233 then you will want to instrument the whole kernel and you should 2234 say y here. If you are doing more targeted fuzzing (like e.g. 2235 filesystem fuzzing with AFL) then you will want to enable coverage 2236 for more specific subsets of files, and should say n here. 2237 2238config KCOV_IRQ_AREA_SIZE 2239 hex "Size of interrupt coverage collection area in words" 2240 depends on KCOV 2241 default 0x40000 2242 help 2243 KCOV uses preallocated per-cpu areas to collect coverage from 2244 soft interrupts. This specifies the size of those areas in the 2245 number of unsigned long words. 2246 2247config KCOV_SELFTEST 2248 bool "Perform short selftests on boot" 2249 depends on KCOV 2250 help 2251 Run short KCOV coverage collection selftests on boot. 2252 On test failure, causes the kernel to panic. Recommended to be 2253 enabled, ensuring critical functionality works as intended. 2254 2255menuconfig RUNTIME_TESTING_MENU 2256 bool "Runtime Testing" 2257 default y 2258 2259if RUNTIME_TESTING_MENU 2260 2261config TEST_DHRY 2262 tristate "Dhrystone benchmark test" 2263 help 2264 Enable this to include the Dhrystone 2.1 benchmark. This test 2265 calculates the number of Dhrystones per second, and the number of 2266 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided 2267 by 1757 (the number of Dhrystones per second obtained on the VAX 2268 11/780, nominally a 1 MIPS machine). 2269 2270 To run the benchmark, it needs to be enabled explicitly, either from 2271 the kernel command line (when built-in), or from userspace (when 2272 built-in or modular). 2273 2274 Run once during kernel boot: 2275 2276 test_dhry.run 2277 2278 Set number of iterations from kernel command line: 2279 2280 test_dhry.iterations=<n> 2281 2282 Set number of iterations from userspace: 2283 2284 echo <n> > /sys/module/test_dhry/parameters/iterations 2285 2286 Trigger manual run from userspace: 2287 2288 echo y > /sys/module/test_dhry/parameters/run 2289 2290 If the number of iterations is <= 0, the test will devise a suitable 2291 number of iterations (test runs for at least 2s) automatically. 2292 This process takes ca. 4s. 2293 2294 If unsure, say N. 2295 2296config LKDTM 2297 tristate "Linux Kernel Dump Test Tool Module" 2298 depends on DEBUG_FS 2299 help 2300 This module enables testing of the different dumping mechanisms by 2301 inducing system failures at predefined crash points. 2302 If you don't need it: say N 2303 Choose M here to compile this code as a module. The module will be 2304 called lkdtm. 2305 2306 Documentation on how to use the module can be found in 2307 Documentation/fault-injection/provoke-crashes.rst 2308 2309config CPUMASK_KUNIT_TEST 2310 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2311 depends on KUNIT 2312 default KUNIT_ALL_TESTS 2313 help 2314 Enable to turn on cpumask tests, running at boot or module load time. 2315 2316 For more information on KUnit and unit tests in general, please refer 2317 to the KUnit documentation in Documentation/dev-tools/kunit/. 2318 2319 If unsure, say N. 2320 2321config TEST_LIST_SORT 2322 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2323 depends on KUNIT 2324 default KUNIT_ALL_TESTS 2325 help 2326 Enable this to turn on 'list_sort()' function test. This test is 2327 executed only once during system boot (so affects only boot time), 2328 or at module load time. 2329 2330 If unsure, say N. 2331 2332config TEST_SORT 2333 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2334 depends on KUNIT 2335 default KUNIT_ALL_TESTS 2336 help 2337 This option enables the self-test function of 'sort()' at boot, 2338 or at module load time. 2339 2340 If unsure, say N. 2341 2342config TEST_DIV64 2343 tristate "64bit/32bit division and modulo test" 2344 depends on DEBUG_KERNEL || m 2345 help 2346 Enable this to turn on 'do_div()' function test. This test is 2347 executed only once during system boot (so affects only boot time), 2348 or at module load time. 2349 2350 If unsure, say N. 2351 2352config TEST_MULDIV64 2353 tristate "mul_u64_u64_div_u64() test" 2354 depends on DEBUG_KERNEL || m 2355 help 2356 Enable this to turn on 'mul_u64_u64_div_u64()' function test. 2357 This test is executed only once during system boot (so affects 2358 only boot time), or at module load time. 2359 2360 If unsure, say N. 2361 2362config TEST_IOV_ITER 2363 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS 2364 depends on KUNIT 2365 depends on MMU 2366 default KUNIT_ALL_TESTS 2367 help 2368 Enable this to turn on testing of the operation of the I/O iterator 2369 (iov_iter). This test is executed only once during system boot (so 2370 affects only boot time), or at module load time. 2371 2372 If unsure, say N. 2373 2374config KPROBES_SANITY_TEST 2375 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2376 depends on DEBUG_KERNEL 2377 depends on KPROBES 2378 depends on KUNIT 2379 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2380 default KUNIT_ALL_TESTS 2381 help 2382 This option provides for testing basic kprobes functionality on 2383 boot. Samples of kprobe and kretprobe are inserted and 2384 verified for functionality. 2385 2386 Say N if you are unsure. 2387 2388config FPROBE_SANITY_TEST 2389 bool "Self test for fprobe" 2390 depends on DEBUG_KERNEL 2391 depends on FPROBE 2392 depends on KUNIT=y 2393 help 2394 This option will enable testing the fprobe when the system boot. 2395 A series of tests are made to verify that the fprobe is functioning 2396 properly. 2397 2398 Say N if you are unsure. 2399 2400config BACKTRACE_SELF_TEST 2401 tristate "Self test for the backtrace code" 2402 depends on DEBUG_KERNEL 2403 help 2404 This option provides a kernel module that can be used to test 2405 the kernel stack backtrace code. This option is not useful 2406 for distributions or general kernels, but only for kernel 2407 developers working on architecture code. 2408 2409 Note that if you want to also test saved backtraces, you will 2410 have to enable STACKTRACE as well. 2411 2412 Say N if you are unsure. 2413 2414config TEST_REF_TRACKER 2415 tristate "Self test for reference tracker" 2416 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2417 select REF_TRACKER 2418 help 2419 This option provides a kernel module performing tests 2420 using reference tracker infrastructure. 2421 2422 Say N if you are unsure. 2423 2424config RBTREE_TEST 2425 tristate "Red-Black tree test" 2426 depends on DEBUG_KERNEL 2427 help 2428 A benchmark measuring the performance of the rbtree library. 2429 Also includes rbtree invariant checks. 2430 2431config REED_SOLOMON_TEST 2432 tristate "Reed-Solomon library test" 2433 depends on DEBUG_KERNEL || m 2434 select REED_SOLOMON 2435 select REED_SOLOMON_ENC16 2436 select REED_SOLOMON_DEC16 2437 help 2438 This option enables the self-test function of rslib at boot, 2439 or at module load time. 2440 2441 If unsure, say N. 2442 2443config INTERVAL_TREE_TEST 2444 tristate "Interval tree test" 2445 depends on DEBUG_KERNEL 2446 select INTERVAL_TREE 2447 help 2448 A benchmark measuring the performance of the interval tree library 2449 2450config PERCPU_TEST 2451 tristate "Per cpu operations test" 2452 depends on m && DEBUG_KERNEL 2453 help 2454 Enable this option to build test module which validates per-cpu 2455 operations. 2456 2457 If unsure, say N. 2458 2459config ATOMIC64_SELFTEST 2460 tristate "Perform an atomic64_t self-test" 2461 help 2462 Enable this option to test the atomic64_t functions at boot or 2463 at module load time. 2464 2465 If unsure, say N. 2466 2467config ASYNC_RAID6_TEST 2468 tristate "Self test for hardware accelerated raid6 recovery" 2469 depends on ASYNC_RAID6_RECOV 2470 select ASYNC_MEMCPY 2471 help 2472 This is a one-shot self test that permutes through the 2473 recovery of all the possible two disk failure scenarios for a 2474 N-disk array. Recovery is performed with the asynchronous 2475 raid6 recovery routines, and will optionally use an offload 2476 engine if one is available. 2477 2478 If unsure, say N. 2479 2480config TEST_HEXDUMP 2481 tristate "Test functions located in the hexdump module at runtime" 2482 2483config PRINTF_KUNIT_TEST 2484 tristate "KUnit test printf() family of functions at runtime" if !KUNIT_ALL_TESTS 2485 depends on KUNIT 2486 default KUNIT_ALL_TESTS 2487 help 2488 Enable this option to test the printf functions at runtime. 2489 2490 If unsure, say N. 2491 2492config SCANF_KUNIT_TEST 2493 tristate "KUnit test scanf() family of functions at runtime" if !KUNIT_ALL_TESTS 2494 depends on KUNIT 2495 default KUNIT_ALL_TESTS 2496 help 2497 Enable this option to test the scanf functions at runtime. 2498 2499 If unsure, say N. 2500 2501config SEQ_BUF_KUNIT_TEST 2502 tristate "KUnit test for seq_buf" if !KUNIT_ALL_TESTS 2503 depends on KUNIT 2504 default KUNIT_ALL_TESTS 2505 help 2506 This builds unit tests for the seq_buf library. 2507 2508 If unsure, say N. 2509 2510config STRING_KUNIT_TEST 2511 tristate "KUnit test string functions at runtime" if !KUNIT_ALL_TESTS 2512 depends on KUNIT 2513 default KUNIT_ALL_TESTS 2514 2515config STRING_HELPERS_KUNIT_TEST 2516 tristate "KUnit test string helpers at runtime" if !KUNIT_ALL_TESTS 2517 depends on KUNIT 2518 default KUNIT_ALL_TESTS 2519 2520config FFS_KUNIT_TEST 2521 tristate "KUnit test ffs-family functions at runtime" if !KUNIT_ALL_TESTS 2522 depends on KUNIT 2523 default KUNIT_ALL_TESTS 2524 help 2525 This builds KUnit tests for ffs-family bit manipulation functions 2526 including ffs(), __ffs(), fls(), __fls(), fls64(), and __ffs64(). 2527 2528 These tests validate mathematical correctness, edge case handling, 2529 and cross-architecture consistency of bit scanning functions. 2530 2531 For more information on KUnit and unit tests in general, 2532 please refer to Documentation/dev-tools/kunit/. 2533 2534config TEST_KSTRTOX 2535 tristate "Test kstrto*() family of functions at runtime" 2536 2537config TEST_BITMAP 2538 tristate "Test bitmap_*() family of functions at runtime" 2539 help 2540 Enable this option to test the bitmap functions at boot. 2541 2542 If unsure, say N. 2543 2544config TEST_XARRAY 2545 tristate "Test the XArray code at runtime" 2546 2547config TEST_MAPLE_TREE 2548 tristate "Test the Maple Tree code at runtime or module load" 2549 help 2550 Enable this option to test the maple tree code functions at boot, or 2551 when the module is loaded. Enable "Debug Maple Trees" will enable 2552 more verbose output on failures. 2553 2554 If unsure, say N. 2555 2556config TEST_RHASHTABLE 2557 tristate "Perform selftest on resizable hash table" 2558 help 2559 Enable this option to test the rhashtable functions at boot. 2560 2561 If unsure, say N. 2562 2563config TEST_IDA 2564 tristate "Perform selftest on IDA functions" 2565 2566config TEST_MISC_MINOR 2567 bool "miscdevice KUnit test" if !KUNIT_ALL_TESTS 2568 depends on KUNIT=y 2569 default KUNIT_ALL_TESTS 2570 help 2571 Kunit test for miscdevice API, specially its behavior in respect to 2572 static and dynamic minor numbers. 2573 2574 KUnit tests run during boot and output the results to the debug log 2575 in TAP format (https://testanything.org/). Only useful for kernel devs 2576 running the KUnit test harness, and not intended for inclusion into a 2577 production build. 2578 2579 For more information on KUnit and unit tests in general please refer 2580 to the KUnit documentation in Documentation/dev-tools/kunit/. 2581 2582 If unsure, say N. 2583 2584config TEST_PARMAN 2585 tristate "Perform selftest on priority array manager" 2586 depends on PARMAN 2587 help 2588 Enable this option to test priority array manager on boot 2589 (or module load). 2590 2591 If unsure, say N. 2592 2593config TEST_LKM 2594 tristate "Test module loading with 'hello world' module" 2595 depends on m 2596 help 2597 This builds the "test_module" module that emits "Hello, world" 2598 on printk when loaded. It is designed to be used for basic 2599 evaluation of the module loading subsystem (for example when 2600 validating module verification). It lacks any extra dependencies, 2601 and will not normally be loaded by the system unless explicitly 2602 requested by name. 2603 2604 If unsure, say N. 2605 2606config TEST_BITOPS 2607 tristate "Test module for compilation of bitops operations" 2608 help 2609 This builds the "test_bitops" module that is much like the 2610 TEST_LKM module except that it does a basic exercise of the 2611 set/clear_bit macros and get_count_order/long to make sure there are 2612 no compiler warnings from C=1 sparse checker or -Wextra 2613 compilations. It has no dependencies and doesn't run or load unless 2614 explicitly requested by name. for example: modprobe test_bitops. 2615 2616 If unsure, say N. 2617 2618config TEST_VMALLOC 2619 tristate "Test module for stress/performance analysis of vmalloc allocator" 2620 default n 2621 depends on MMU 2622 help 2623 This builds the "test_vmalloc" module that should be used for 2624 stress and performance analysis. So, any new change for vmalloc 2625 subsystem can be evaluated from performance and stability point 2626 of view. 2627 2628 If unsure, say N. 2629 2630config TEST_BPF 2631 tristate "Test BPF filter functionality" 2632 depends on m && NET 2633 help 2634 This builds the "test_bpf" module that runs various test vectors 2635 against the BPF interpreter or BPF JIT compiler depending on the 2636 current setting. This is in particular useful for BPF JIT compiler 2637 development, but also to run regression tests against changes in 2638 the interpreter code. It also enables test stubs for eBPF maps and 2639 verifier used by user space verifier testsuite. 2640 2641 If unsure, say N. 2642 2643config FIND_BIT_BENCHMARK 2644 tristate "Test find_bit functions" 2645 help 2646 This builds the "test_find_bit" module that measure find_*_bit() 2647 functions performance. 2648 2649 If unsure, say N. 2650 2651config FIND_BIT_BENCHMARK_RUST 2652 tristate "Test find_bit functions in Rust" 2653 depends on RUST 2654 help 2655 This builds the "find_bit_benchmark_rust" module. It is a micro 2656 benchmark that measures the performance of Rust functions that 2657 correspond to the find_*_bit() operations in C. It follows the 2658 FIND_BIT_BENCHMARK closely but will in general not yield same 2659 numbers due to extra bounds checks and overhead of foreign 2660 function calls. 2661 2662 If unsure, say N. 2663 2664config TEST_FIRMWARE 2665 tristate "Test firmware loading via userspace interface" 2666 depends on FW_LOADER 2667 help 2668 This builds the "test_firmware" module that creates a userspace 2669 interface for testing firmware loading. This can be used to 2670 control the triggering of firmware loading without needing an 2671 actual firmware-using device. The contents can be rechecked by 2672 userspace. 2673 2674 If unsure, say N. 2675 2676config TEST_SYSCTL 2677 tristate "sysctl test driver" 2678 depends on PROC_SYSCTL 2679 help 2680 This builds the "test_sysctl" module. This driver enables to test the 2681 proc sysctl interfaces available to drivers safely without affecting 2682 production knobs which might alter system functionality. 2683 2684 If unsure, say N. 2685 2686config BITOPS_KUNIT 2687 tristate "KUnit test for bitops" if !KUNIT_ALL_TESTS 2688 depends on KUNIT 2689 default KUNIT_ALL_TESTS 2690 help 2691 This option enables the KUnit test for the bitops library 2692 which provides functions for bit operations. 2693 2694 Note that this is derived from the original test_bitops module. 2695 For micro-benchmarks and compiler warning checks, enable TEST_BITOPS. 2696 2697 If unsure, say N. 2698 2699config BITFIELD_KUNIT 2700 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2701 depends on KUNIT 2702 default KUNIT_ALL_TESTS 2703 help 2704 Enable this option to test the bitfield functions at boot. 2705 2706 KUnit tests run during boot and output the results to the debug log 2707 in TAP format (http://testanything.org/). Only useful for kernel devs 2708 running the KUnit test harness, and not intended for inclusion into a 2709 production build. 2710 2711 For more information on KUnit and unit tests in general please refer 2712 to the KUnit documentation in Documentation/dev-tools/kunit/. 2713 2714 If unsure, say N. 2715 2716config CHECKSUM_KUNIT 2717 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS 2718 depends on KUNIT 2719 default KUNIT_ALL_TESTS 2720 help 2721 Enable this option to test the checksum functions at boot. 2722 2723 KUnit tests run during boot and output the results to the debug log 2724 in TAP format (http://testanything.org/). Only useful for kernel devs 2725 running the KUnit test harness, and not intended for inclusion into a 2726 production build. 2727 2728 For more information on KUnit and unit tests in general please refer 2729 to the KUnit documentation in Documentation/dev-tools/kunit/. 2730 2731 If unsure, say N. 2732 2733config UTIL_MACROS_KUNIT 2734 tristate "KUnit test util_macros.h functions at runtime" if !KUNIT_ALL_TESTS 2735 depends on KUNIT 2736 default KUNIT_ALL_TESTS 2737 help 2738 Enable this option to test the util_macros.h function at boot. 2739 2740 KUnit tests run during boot and output the results to the debug log 2741 in TAP format (http://testanything.org/). Only useful for kernel devs 2742 running the KUnit test harness, and not intended for inclusion into a 2743 production build. 2744 2745 For more information on KUnit and unit tests in general please refer 2746 to the KUnit documentation in Documentation/dev-tools/kunit/. 2747 2748 If unsure, say N. 2749 2750config HASH_KUNIT_TEST 2751 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2752 depends on KUNIT 2753 default KUNIT_ALL_TESTS 2754 help 2755 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2756 integer (<linux/hash.h>) hash functions on boot. 2757 2758 KUnit tests run during boot and output the results to the debug log 2759 in TAP format (https://testanything.org/). Only useful for kernel devs 2760 running the KUnit test harness, and not intended for inclusion into a 2761 production build. 2762 2763 For more information on KUnit and unit tests in general please refer 2764 to the KUnit documentation in Documentation/dev-tools/kunit/. 2765 2766 This is intended to help people writing architecture-specific 2767 optimized versions. If unsure, say N. 2768 2769config RESOURCE_KUNIT_TEST 2770 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2771 depends on KUNIT 2772 default KUNIT_ALL_TESTS 2773 select GET_FREE_REGION 2774 help 2775 This builds the resource API unit test. 2776 Tests the logic of API provided by resource.c and ioport.h. 2777 For more information on KUnit and unit tests in general please refer 2778 to the KUnit documentation in Documentation/dev-tools/kunit/. 2779 2780 If unsure, say N. 2781 2782config SYSCTL_KUNIT_TEST 2783 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2784 depends on KUNIT 2785 default KUNIT_ALL_TESTS 2786 help 2787 This builds the proc sysctl unit test, which runs on boot. 2788 Tests the API contract and implementation correctness of sysctl. 2789 For more information on KUnit and unit tests in general please refer 2790 to the KUnit documentation in Documentation/dev-tools/kunit/. 2791 2792 If unsure, say N. 2793 2794config KFIFO_KUNIT_TEST 2795 tristate "KUnit Test for the generic kernel FIFO implementation" if !KUNIT_ALL_TESTS 2796 depends on KUNIT 2797 default KUNIT_ALL_TESTS 2798 help 2799 This builds the generic FIFO implementation KUnit test suite. 2800 It tests that the API and basic functionality of the kfifo type 2801 and associated macros. 2802 2803 For more information on KUnit and unit tests in general please refer 2804 to the KUnit documentation in Documentation/dev-tools/kunit/. 2805 2806 If unsure, say N. 2807 2808config LIST_KUNIT_TEST 2809 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2810 depends on KUNIT 2811 default KUNIT_ALL_TESTS 2812 help 2813 This builds the linked list KUnit test suite. 2814 It tests that the API and basic functionality of the list_head type 2815 and associated macros. 2816 2817 KUnit tests run during boot and output the results to the debug log 2818 in TAP format (https://testanything.org/). Only useful for kernel devs 2819 running the KUnit test harness, and not intended for inclusion into a 2820 production build. 2821 2822 For more information on KUnit and unit tests in general please refer 2823 to the KUnit documentation in Documentation/dev-tools/kunit/. 2824 2825 If unsure, say N. 2826 2827config LIST_PRIVATE_KUNIT_TEST 2828 tristate "KUnit Test for Kernel Private Linked-list structures" if !KUNIT_ALL_TESTS 2829 depends on KUNIT 2830 default KUNIT_ALL_TESTS 2831 help 2832 This builds the KUnit test for the private linked-list primitives 2833 defined in include/linux/list_private.h. 2834 2835 These primitives allow manipulation of list_head members that are 2836 marked as private and require special accessors (ACCESS_PRIVATE) 2837 to strip qualifiers or handle encapsulation. 2838 2839 If unsure, say N. 2840 2841config HASHTABLE_KUNIT_TEST 2842 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS 2843 depends on KUNIT 2844 default KUNIT_ALL_TESTS 2845 help 2846 This builds the hashtable KUnit test suite. 2847 It tests the basic functionality of the API defined in 2848 include/linux/hashtable.h. For more information on KUnit and 2849 unit tests in general please refer to the KUnit documentation 2850 in Documentation/dev-tools/kunit/. 2851 2852 If unsure, say N. 2853 2854config LINEAR_RANGES_TEST 2855 tristate "KUnit test for linear_ranges" 2856 depends on KUNIT 2857 select LINEAR_RANGES 2858 help 2859 This builds the linear_ranges unit test, which runs on boot. 2860 Tests the linear_ranges logic correctness. 2861 For more information on KUnit and unit tests in general please refer 2862 to the KUnit documentation in Documentation/dev-tools/kunit/. 2863 2864 If unsure, say N. 2865 2866config CONTEXT_ANALYSIS_TEST 2867 bool "Compiler context-analysis warnings test" 2868 depends on EXPERT 2869 help 2870 This builds the test for compiler-based context analysis. The test 2871 does not add executable code to the kernel, but is meant to test that 2872 common patterns supported by the analysis do not result in false 2873 positive warnings. 2874 2875 When adding support for new context locks, it is strongly recommended 2876 to add supported patterns to this test. 2877 2878 If unsure, say N. 2879 2880config LIVEUPDATE_TEST 2881 bool "Live Update Kernel Test" 2882 default n 2883 depends on LIVEUPDATE 2884 help 2885 Enable a built-in kernel test module for the Live Update 2886 Orchestrator. 2887 2888 This module validates the File-Lifecycle-Bound subsystem by 2889 registering a set of mock FLB objects with any real file handlers 2890 that support live update (such as the memfd handler). 2891 2892 When live update operations are performed, this test module will 2893 output messages to the kernel log (dmesg), confirming that its 2894 registration and various callback functions (preserve, retrieve, 2895 finish, etc.) are being invoked correctly. 2896 2897 This is a debugging and regression testing tool for developers 2898 working on the Live Update subsystem. It should not be enabled in 2899 production kernels. 2900 2901 If unsure, say N 2902 2903config CMDLINE_KUNIT_TEST 2904 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2905 depends on KUNIT 2906 default KUNIT_ALL_TESTS 2907 help 2908 This builds the cmdline API unit test. 2909 Tests the logic of API provided by cmdline.c. 2910 For more information on KUnit and unit tests in general please refer 2911 to the KUnit documentation in Documentation/dev-tools/kunit/. 2912 2913 If unsure, say N. 2914 2915config BASE64_KUNIT 2916 tristate "KUnit test for base64 decoding and encoding" if !KUNIT_ALL_TESTS 2917 depends on KUNIT 2918 default KUNIT_ALL_TESTS 2919 help 2920 This builds the base64 unit tests. 2921 2922 The tests cover the encoding and decoding logic of Base64 functions 2923 in the kernel. 2924 In addition to correctness checks, simple performance benchmarks 2925 for both encoding and decoding are also included. 2926 2927 For more information on KUnit and unit tests in general please refer 2928 to the KUnit documentation in Documentation/dev-tools/kunit/. 2929 2930 If unsure, say N. 2931 2932config BITS_TEST 2933 tristate "KUnit test for bit functions and macros" if !KUNIT_ALL_TESTS 2934 depends on KUNIT 2935 default KUNIT_ALL_TESTS 2936 help 2937 This builds the bits unit test. 2938 Tests the logic of macros defined in bits.h. 2939 For more information on KUnit and unit tests in general please refer 2940 to the KUnit documentation in Documentation/dev-tools/kunit/. 2941 2942 If unsure, say N. 2943 2944config SLUB_KUNIT_TEST 2945 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2946 depends on SLUB_DEBUG && KUNIT 2947 default KUNIT_ALL_TESTS 2948 help 2949 This builds SLUB allocator unit test. 2950 Tests SLUB cache debugging functionality. 2951 For more information on KUnit and unit tests in general please refer 2952 to the KUnit documentation in Documentation/dev-tools/kunit/. 2953 2954 If unsure, say N. 2955 2956config RATIONAL_KUNIT_TEST 2957 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2958 depends on KUNIT && RATIONAL 2959 default KUNIT_ALL_TESTS 2960 help 2961 This builds the rational math unit test. 2962 For more information on KUnit and unit tests in general please refer 2963 to the KUnit documentation in Documentation/dev-tools/kunit/. 2964 2965 If unsure, say N. 2966 2967config MEMCPY_KUNIT_TEST 2968 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2969 depends on KUNIT 2970 default KUNIT_ALL_TESTS 2971 help 2972 Builds unit tests for memcpy(), memmove(), and memset() functions. 2973 For more information on KUnit and unit tests in general please refer 2974 to the KUnit documentation in Documentation/dev-tools/kunit/. 2975 2976 If unsure, say N. 2977 2978config MIN_HEAP_KUNIT_TEST 2979 tristate "Min heap test" if !KUNIT_ALL_TESTS 2980 depends on KUNIT 2981 default KUNIT_ALL_TESTS 2982 help 2983 This option enables the KUnit test suite for the min heap library 2984 which provides functions for creating and managing min heaps. 2985 The test suite checks the functionality of the min heap library. 2986 2987 If unsure, say N 2988 2989config IS_SIGNED_TYPE_KUNIT_TEST 2990 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2991 depends on KUNIT 2992 default KUNIT_ALL_TESTS 2993 help 2994 Builds unit tests for the is_signed_type() macro. 2995 2996 For more information on KUnit and unit tests in general please refer 2997 to the KUnit documentation in Documentation/dev-tools/kunit/. 2998 2999 If unsure, say N. 3000 3001config OVERFLOW_KUNIT_TEST 3002 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 3003 depends on KUNIT 3004 default KUNIT_ALL_TESTS 3005 help 3006 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 3007 related functions. 3008 3009 For more information on KUnit and unit tests in general please refer 3010 to the KUnit documentation in Documentation/dev-tools/kunit/. 3011 3012 If unsure, say N. 3013 3014config RANDSTRUCT_KUNIT_TEST 3015 tristate "Test randstruct structure layout randomization at runtime" if !KUNIT_ALL_TESTS 3016 depends on KUNIT 3017 default KUNIT_ALL_TESTS 3018 help 3019 Builds unit tests for the checking CONFIG_RANDSTRUCT=y, which 3020 randomizes structure layouts. 3021 3022config STACKINIT_KUNIT_TEST 3023 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 3024 depends on KUNIT 3025 default KUNIT_ALL_TESTS 3026 help 3027 Test if the kernel is zero-initializing stack variables and 3028 padding. Coverage is controlled by compiler flags, 3029 CONFIG_INIT_STACK_ALL_PATTERN or CONFIG_INIT_STACK_ALL_ZERO. 3030 3031config FORTIFY_KUNIT_TEST 3032 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 3033 depends on KUNIT 3034 default KUNIT_ALL_TESTS 3035 help 3036 Builds unit tests for checking internals of FORTIFY_SOURCE as used 3037 by the str*() and mem*() family of functions. For testing runtime 3038 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 3039 3040config LONGEST_SYM_KUNIT_TEST 3041 tristate "Test the longest symbol possible" if !KUNIT_ALL_TESTS 3042 depends on KUNIT && KPROBES 3043 depends on !PREFIX_SYMBOLS && !CFI && !GCOV_KERNEL 3044 default KUNIT_ALL_TESTS 3045 help 3046 Tests the longest symbol possible 3047 3048 If unsure, say N. 3049 3050config HW_BREAKPOINT_KUNIT_TEST 3051 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 3052 depends on HAVE_HW_BREAKPOINT 3053 depends on KUNIT=y 3054 default KUNIT_ALL_TESTS 3055 help 3056 Tests for hw_breakpoint constraints accounting. 3057 3058 If unsure, say N. 3059 3060config SIPHASH_KUNIT_TEST 3061 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 3062 depends on KUNIT 3063 default KUNIT_ALL_TESTS 3064 help 3065 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 3066 functions on boot (or module load). 3067 3068 This is intended to help people writing architecture-specific 3069 optimized versions. If unsure, say N. 3070 3071config USERCOPY_KUNIT_TEST 3072 tristate "KUnit Test for user/kernel boundary protections" 3073 depends on KUNIT 3074 default KUNIT_ALL_TESTS 3075 help 3076 This builds the "usercopy_kunit" module that runs sanity checks 3077 on the copy_to/from_user infrastructure, making sure basic 3078 user/kernel boundary testing is working. 3079 3080config BLACKHOLE_DEV_KUNIT_TEST 3081 tristate "Test blackhole netdev functionality" if !KUNIT_ALL_TESTS 3082 depends on NET 3083 depends on KUNIT 3084 default KUNIT_ALL_TESTS 3085 help 3086 This builds the "blackhole_dev_kunit" module that validates the 3087 data path through this blackhole netdev. 3088 3089 If unsure, say N. 3090 3091config TEST_UDELAY 3092 tristate "udelay test driver" 3093 help 3094 This builds the "udelay_test" module that helps to make sure 3095 that udelay() is working properly. 3096 3097 If unsure, say N. 3098 3099config TEST_STATIC_KEYS 3100 tristate "Test static keys" 3101 depends on m 3102 help 3103 Test the static key interfaces. 3104 3105 If unsure, say N. 3106 3107config TEST_DYNAMIC_DEBUG 3108 tristate "Test DYNAMIC_DEBUG" 3109 depends on DYNAMIC_DEBUG 3110 help 3111 This module registers a tracer callback to count enabled 3112 pr_debugs in a 'do_debugging' function, then alters their 3113 enablements, calls the function, and compares counts. 3114 3115 If unsure, say N. 3116 3117config TEST_KMOD 3118 tristate "kmod stress tester" 3119 depends on m 3120 select TEST_LKM 3121 help 3122 Test the kernel's module loading mechanism: kmod. kmod implements 3123 support to load modules using the Linux kernel's usermode helper. 3124 This test provides a series of tests against kmod. 3125 3126 Although technically you can either build test_kmod as a module or 3127 into the kernel we disallow building it into the kernel since 3128 it stress tests request_module() and this will very likely cause 3129 some issues by taking over precious threads available from other 3130 module load requests, ultimately this could be fatal. 3131 3132 To run tests run: 3133 3134 tools/testing/selftests/kmod/kmod.sh --help 3135 3136 If unsure, say N. 3137 3138config TEST_RUNTIME 3139 bool 3140 3141config TEST_RUNTIME_MODULE 3142 bool 3143 3144config TEST_KALLSYMS 3145 tristate "module kallsyms find_symbol() test" 3146 depends on m 3147 select TEST_RUNTIME 3148 select TEST_RUNTIME_MODULE 3149 select TEST_KALLSYMS_A 3150 select TEST_KALLSYMS_B 3151 select TEST_KALLSYMS_C 3152 select TEST_KALLSYMS_D 3153 help 3154 This allows us to stress test find_symbol() through the kallsyms 3155 used to place symbols on the kernel ELF kallsyms and modules kallsyms 3156 where we place kernel symbols such as exported symbols. 3157 3158 We have four test modules: 3159 3160 A: has KALLSYSMS_NUMSYMS exported symbols 3161 B: uses one of A's symbols 3162 C: adds KALLSYMS_SCALE_FACTOR * KALLSYSMS_NUMSYMS exported 3163 D: adds 2 * the symbols than C 3164 3165 We stress test find_symbol() through two means: 3166 3167 1) Upon load of B it will trigger simplify_symbols() to look for the 3168 one symbol it uses from the module A with tons of symbols. This is an 3169 indirect way for us to have B call resolve_symbol_wait() upon module 3170 load. This will eventually call find_symbol() which will eventually 3171 try to find the symbols used with find_exported_symbol_in_section(). 3172 find_exported_symbol_in_section() uses bsearch() so a binary search 3173 for each symbol. Binary search will at worst be O(log(n)) so the 3174 larger TEST_MODULE_KALLSYSMS the worse the search. 3175 3176 2) The selftests should load C first, before B. Upon B's load towards 3177 the end right before we call module B's init routine we get 3178 complete_formation() called on the module. That will first check 3179 for duplicate symbols with the call to verify_exported_symbols(). 3180 That is when we'll force iteration on module C's insane symbol list. 3181 Since it has 10 * KALLSYMS_NUMSYMS it means we can first test 3182 just loading B without C. The amount of time it takes to load C Vs 3183 B can give us an idea of the impact growth of the symbol space and 3184 give us projection. Module A only uses one symbol from B so to allow 3185 this scaling in module C to be proportional, if it used more symbols 3186 then the first test would be doing more and increasing just the 3187 search space would be slightly different. The last module, module D 3188 will just increase the search space by twice the number of symbols in 3189 C so to allow for full projects. 3190 3191 tools/testing/selftests/module/find_symbol.sh 3192 3193 The current defaults will incur a build delay of about 7 minutes 3194 on an x86_64 with only 8 cores. Enable this only if you want to 3195 stress test find_symbol() with thousands of symbols. At the same 3196 time this is also useful to test building modules with thousands of 3197 symbols, and if BTF is enabled this also stress tests adding BTF 3198 information for each module. Currently enabling many more symbols 3199 will segfault the build system. 3200 3201 If unsure, say N. 3202 3203if TEST_KALLSYMS 3204 3205config TEST_KALLSYMS_A 3206 tristate 3207 depends on m 3208 3209config TEST_KALLSYMS_B 3210 tristate 3211 depends on m 3212 3213config TEST_KALLSYMS_C 3214 tristate 3215 depends on m 3216 3217config TEST_KALLSYMS_D 3218 tristate 3219 depends on m 3220 3221choice 3222 prompt "Kallsym test range" 3223 default TEST_KALLSYMS_LARGE 3224 help 3225 Selecting something other than "Fast" will enable tests which slow 3226 down the build and may crash your build. 3227 3228config TEST_KALLSYMS_FAST 3229 bool "Fast builds" 3230 help 3231 You won't really be testing kallsysms, so this just helps fast builds 3232 when allmodconfig is used.. 3233 3234config TEST_KALLSYMS_LARGE 3235 bool "Enable testing kallsyms with large exports" 3236 help 3237 This will enable larger number of symbols. This will slow down 3238 your build considerably. 3239 3240config TEST_KALLSYMS_MAX 3241 bool "Known kallsysms limits" 3242 help 3243 This will enable exports to the point we know we'll start crashing 3244 builds. 3245 3246endchoice 3247 3248config TEST_KALLSYMS_NUMSYMS 3249 int "test kallsyms number of symbols" 3250 range 2 10000 3251 default 2 if TEST_KALLSYMS_FAST 3252 default 100 if TEST_KALLSYMS_LARGE 3253 default 10000 if TEST_KALLSYMS_MAX 3254 help 3255 The number of symbols to create on TEST_KALLSYMS_A, only one of which 3256 module TEST_KALLSYMS_B will use. This also will be used 3257 for how many symbols TEST_KALLSYMS_C will have, scaled up by 3258 TEST_KALLSYMS_SCALE_FACTOR. Note that setting this to 10,000 will 3259 trigger a segfault today, don't use anything close to it unless 3260 you are aware that this should not be used for automated build tests. 3261 3262config TEST_KALLSYMS_SCALE_FACTOR 3263 int "test kallsyms scale factor" 3264 default 8 3265 help 3266 How many more unusued symbols will TEST_KALLSYSMS_C have than 3267 TEST_KALLSYMS_A. If 8, then module C will have 8 * syms 3268 than module A. Then TEST_KALLSYMS_D will have double the amount 3269 of symbols than C so to allow projections. 3270 3271endif # TEST_KALLSYMS 3272 3273config TEST_DEBUG_VIRTUAL 3274 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 3275 depends on DEBUG_VIRTUAL 3276 help 3277 Test the kernel's ability to detect incorrect calls to 3278 virt_to_phys() done against the non-linear part of the 3279 kernel's virtual address map. 3280 3281 If unsure, say N. 3282 3283config TEST_MEMCAT_P 3284 tristate "Test memcat_p() helper function" 3285 help 3286 Test the memcat_p() helper for correctly merging two 3287 pointer arrays together. 3288 3289 If unsure, say N. 3290 3291config TEST_OBJAGG 3292 tristate "Perform selftest on object aggreration manager" 3293 default n 3294 depends on OBJAGG 3295 help 3296 Enable this option to test object aggregation manager on boot 3297 (or module load). 3298 3299config TEST_MEMINIT 3300 tristate "Test heap/page initialization" 3301 help 3302 Test if the kernel is zero-initializing heap and page allocations. 3303 This can be useful to test init_on_alloc and init_on_free features. 3304 3305 If unsure, say N. 3306 3307config TEST_HMM 3308 tristate "Test HMM (Heterogeneous Memory Management)" 3309 depends on TRANSPARENT_HUGEPAGE 3310 depends on DEVICE_PRIVATE 3311 select HMM_MIRROR 3312 select MMU_NOTIFIER 3313 help 3314 This is a pseudo device driver solely for testing HMM. 3315 Say M here if you want to build the HMM test module. 3316 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 3317 3318 If unsure, say N. 3319 3320config TEST_FREE_PAGES 3321 tristate "Test freeing pages" 3322 help 3323 Test that a memory leak does not occur due to a race between 3324 freeing a block of pages and a speculative page reference. 3325 Loading this module is safe if your kernel has the bug fixed. 3326 If the bug is not fixed, it will leak gigabytes of memory and 3327 probably OOM your system. 3328 3329config TEST_FPU 3330 tristate "Test floating point operations in kernel space" 3331 depends on ARCH_HAS_KERNEL_FPU_SUPPORT && !KCOV_INSTRUMENT_ALL 3332 help 3333 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 3334 which will trigger a sequence of floating point operations. This is used 3335 for self-testing floating point control register setting in 3336 kernel_fpu_begin(). 3337 3338 If unsure, say N. 3339 3340config TEST_CLOCKSOURCE_WATCHDOG 3341 tristate "Test clocksource watchdog in kernel space" 3342 depends on CLOCKSOURCE_WATCHDOG 3343 help 3344 Enable this option to create a kernel module that will trigger 3345 a test of the clocksource watchdog. This module may be loaded 3346 via modprobe or insmod in which case it will run upon being 3347 loaded, or it may be built in, in which case it will run 3348 shortly after boot. 3349 3350 If unsure, say N. 3351 3352config TEST_OBJPOOL 3353 tristate "Test module for correctness and stress of objpool" 3354 default n 3355 depends on m && DEBUG_KERNEL 3356 help 3357 This builds the "test_objpool" module that should be used for 3358 correctness verification and concurrent testings of objects 3359 allocation and reclamation. 3360 3361 If unsure, say N. 3362 3363config TEST_KEXEC_HANDOVER 3364 bool "Test for Kexec HandOver" 3365 default n 3366 depends on KEXEC_HANDOVER 3367 help 3368 This option enables test for Kexec HandOver (KHO). 3369 The test consists of two parts: saving kernel data before kexec and 3370 restoring the data after kexec and verifying that it was properly 3371 handed over. This test module creates and saves data on the boot of 3372 the first kernel and restores and verifies the data on the boot of 3373 kexec'ed kernel. 3374 3375 For detailed documentation about KHO, see Documentation/core-api/kho. 3376 3377 To run the test run: 3378 3379 tools/testing/selftests/kho/vmtest.sh -h 3380 3381 If unsure, say N. 3382 3383config RATELIMIT_KUNIT_TEST 3384 tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS 3385 depends on KUNIT 3386 default KUNIT_ALL_TESTS 3387 help 3388 This builds the "test_ratelimit" module that should be used 3389 for correctness verification and concurrent testings of rate 3390 limiting. 3391 3392 If unsure, say N. 3393 3394config UUID_KUNIT_TEST 3395 tristate "KUnit test for UUID" if !KUNIT_ALL_TESTS 3396 depends on KUNIT 3397 default KUNIT_ALL_TESTS 3398 help 3399 This option enables the KUnit test suite for the uuid library, 3400 which provides functions for generating and parsing UUID and GUID. 3401 The test suite checks parsing of UUID and GUID strings. 3402 3403 If unsure, say N. 3404 3405config INT_POW_KUNIT_TEST 3406 tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS 3407 depends on KUNIT 3408 default KUNIT_ALL_TESTS 3409 help 3410 This option enables the KUnit test suite for the int_pow function, 3411 which performs integer exponentiation. The test suite is designed to 3412 verify that the implementation of int_pow correctly computes the power 3413 of a given base raised to a given exponent. 3414 3415 Enabling this option will include tests that check various scenarios 3416 and edge cases to ensure the accuracy and reliability of the exponentiation 3417 function. 3418 3419 If unsure, say N 3420 3421config INT_SQRT_KUNIT_TEST 3422 tristate "Integer square root test" if !KUNIT_ALL_TESTS 3423 depends on KUNIT 3424 default KUNIT_ALL_TESTS 3425 help 3426 This option enables the KUnit test suite for the int_sqrt() function, 3427 which performs square root calculation. The test suite checks 3428 various scenarios, including edge cases, to ensure correctness. 3429 3430 Enabling this option will include tests that check various scenarios 3431 and edge cases to ensure the accuracy and reliability of the square root 3432 function. 3433 3434 If unsure, say N 3435 3436config INT_LOG_KUNIT_TEST 3437 tristate "Integer log (int_log) test" if !KUNIT_ALL_TESTS 3438 depends on KUNIT 3439 default KUNIT_ALL_TESTS 3440 help 3441 This option enables the KUnit test suite for the int_log library, which 3442 provides two functions to compute the integer logarithm in base 2 and 3443 base 10, called respectively as intlog2 and intlog10. 3444 3445 If unsure, say N 3446 3447config GCD_KUNIT_TEST 3448 tristate "Greatest common divisor test" if !KUNIT_ALL_TESTS 3449 depends on KUNIT 3450 default KUNIT_ALL_TESTS 3451 help 3452 This option enables the KUnit test suite for the gcd() function, 3453 which computes the greatest common divisor of two numbers. 3454 3455 This test suite verifies the correctness of gcd() across various 3456 scenarios, including edge cases. 3457 3458 If unsure, say N 3459 3460config PRIME_NUMBERS_KUNIT_TEST 3461 tristate "Prime number generator test" if !KUNIT_ALL_TESTS 3462 depends on KUNIT 3463 depends on PRIME_NUMBERS 3464 default KUNIT_ALL_TESTS 3465 help 3466 This option enables the KUnit test suite for the {is,next}_prime_number 3467 functions. 3468 3469 Enabling this option will include tests that compare the prime number 3470 generator functions against a brute force implementation. 3471 3472 If unsure, say N 3473 3474config GLOB_KUNIT_TEST 3475 tristate "Glob matching test" if !KUNIT_ALL_TESTS 3476 depends on GLOB 3477 depends on KUNIT 3478 default KUNIT_ALL_TESTS 3479 help 3480 Enable this option to test the glob functions at runtime. 3481 3482 This test suite verifies the correctness of glob_match() across various 3483 scenarios, including edge cases. 3484 3485 If unsure, say N 3486 3487endif # RUNTIME_TESTING_MENU 3488 3489config ARCH_USE_MEMTEST 3490 bool 3491 help 3492 An architecture should select this when it uses early_memtest() 3493 during boot process. 3494 3495config MEMTEST 3496 bool "Memtest" 3497 depends on ARCH_USE_MEMTEST 3498 help 3499 This option adds a kernel parameter 'memtest', which allows memtest 3500 to be set and executed. 3501 memtest=0, mean disabled; -- default 3502 memtest=1, mean do 1 test pattern; 3503 ... 3504 memtest=17, mean do 17 test patterns. 3505 If you are unsure how to answer this question, answer N. 3506 3507 3508 3509config HYPERV_TESTING 3510 bool "Microsoft Hyper-V driver testing" 3511 default n 3512 depends on HYPERV && DEBUG_FS 3513 help 3514 Select this option to enable Hyper-V vmbus testing. 3515 3516endmenu # "Kernel Testing and Coverage" 3517 3518menu "Rust hacking" 3519 3520config RUST_DEBUG_ASSERTIONS 3521 bool "Debug assertions" 3522 depends on RUST 3523 help 3524 Enables rustc's `-Cdebug-assertions` codegen option. 3525 3526 This flag lets you turn `cfg(debug_assertions)` conditional 3527 compilation on or off. This can be used to enable extra debugging 3528 code in development but not in production. For example, it controls 3529 the behavior of the standard library's `debug_assert!` macro. 3530 3531 Note that this will apply to all Rust code, including `core`. 3532 3533 If unsure, say N. 3534 3535config RUST_OVERFLOW_CHECKS 3536 bool "Overflow checks" 3537 default y 3538 depends on RUST 3539 help 3540 Enables rustc's `-Coverflow-checks` codegen option. 3541 3542 This flag allows you to control the behavior of runtime integer 3543 overflow. When overflow-checks are enabled, a Rust panic will occur 3544 on overflow. 3545 3546 Note that this will apply to all Rust code, including `core`. 3547 3548 If unsure, say Y. 3549 3550config RUST_BUILD_ASSERT_ALLOW 3551 bool "Allow unoptimized build-time assertions" 3552 depends on RUST 3553 help 3554 Controls how `build_error!` and `build_assert!` are handled during the build. 3555 3556 If calls to them exist in the binary, it may indicate a violated invariant 3557 or that the optimizer failed to verify the invariant during compilation. 3558 3559 This should not happen, thus by default the build is aborted. However, 3560 as an escape hatch, you can choose Y here to ignore them during build 3561 and let the check be carried at runtime (with `panic!` being called if 3562 the check fails). 3563 3564 If unsure, say N. 3565 3566config RUST_KERNEL_DOCTESTS 3567 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS 3568 depends on RUST && KUNIT=y 3569 default KUNIT_ALL_TESTS 3570 help 3571 This builds the documentation tests of the `kernel` crate 3572 as KUnit tests. 3573 3574 For more information on KUnit and unit tests in general, 3575 please refer to the KUnit documentation in Documentation/dev-tools/kunit/. 3576 3577 If unsure, say N. 3578 3579endmenu # "Rust" 3580 3581endmenu # Kernel hacking 3582