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