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