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 jiffie" 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 209endmenu # "printk and dmesg options" 210 211config DEBUG_KERNEL 212 bool "Kernel debugging" 213 help 214 Say Y here if you are developing drivers or trying to debug and 215 identify kernel problems. 216 217config DEBUG_MISC 218 bool "Miscellaneous debug code" 219 default DEBUG_KERNEL 220 depends on DEBUG_KERNEL 221 help 222 Say Y here if you need to enable miscellaneous debug code that should 223 be under a more specific debug option but isn't. 224 225menu "Compile-time checks and compiler options" 226 227config DEBUG_INFO 228 bool 229 help 230 A kernel debug info option other than "None" has been selected 231 in the "Debug information" choice below, indicating that debug 232 information will be generated for build targets. 233 234# Clang generates .uleb128 with label differences for DWARF v5, a feature that 235# older binutils ports do not support when utilizing RISC-V style linker 236# relaxation: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 237config AS_HAS_NON_CONST_ULEB128 238 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) 239 240choice 241 prompt "Debug information" 242 depends on DEBUG_KERNEL 243 help 244 Selecting something other than "None" results in a kernel image 245 that will include debugging info resulting in a larger kernel image. 246 This adds debug symbols to the kernel and modules (gcc -g), and 247 is needed if you intend to use kernel crashdump or binary object 248 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 249 250 Choose which version of DWARF debug info to emit. If unsure, 251 select "Toolchain default". 252 253config DEBUG_INFO_NONE 254 bool "Disable debug information" 255 help 256 Do not build the kernel with debugging information, which will 257 result in a faster and smaller build. 258 259config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 260 bool "Rely on the toolchain's implicit default DWARF version" 261 select DEBUG_INFO 262 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) 263 help 264 The implicit default version of DWARF debug info produced by a 265 toolchain changes over time. 266 267 This can break consumers of the debug info that haven't upgraded to 268 support newer revisions, and prevent testing newer versions, but 269 those should be less common scenarios. 270 271config DEBUG_INFO_DWARF4 272 bool "Generate DWARF Version 4 debuginfo" 273 select DEBUG_INFO 274 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502) 275 help 276 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2 277 if using clang without clang's integrated assembler, and gdb 7.0+. 278 279 If you have consumers of DWARF debug info that are not ready for 280 newer revisions of DWARF, you may wish to choose this or have your 281 config select this. 282 283config DEBUG_INFO_DWARF5 284 bool "Generate DWARF Version 5 debuginfo" 285 select DEBUG_INFO 286 depends on !ARCH_HAS_BROKEN_DWARF5 287 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_ULEB128) 288 help 289 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 290 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 291 draft features until 7.0), and gdb 8.0+. 292 293 Changes to the structure of debug info in Version 5 allow for around 294 15-18% savings in resulting image and debug info section sizes as 295 compared to DWARF Version 4. DWARF Version 5 standardizes previous 296 extensions such as accelerators for symbol indexing and the format 297 for fission (.dwo/.dwp) files. Users may not want to select this 298 config if they rely on tooling that has not yet been updated to 299 support DWARF Version 5. 300 301endchoice # "Debug information" 302 303if DEBUG_INFO 304 305config DEBUG_INFO_REDUCED 306 bool "Reduce debugging information" 307 help 308 If you say Y here gcc is instructed to generate less debugging 309 information for structure types. This means that tools that 310 need full debugging information (like kgdb or systemtap) won't 311 be happy. But if you merely need debugging information to 312 resolve line numbers there is no loss. Advantage is that 313 build directory object sizes shrink dramatically over a full 314 DEBUG_INFO build and compile times are reduced too. 315 Only works with newer gcc versions. 316 317choice 318 prompt "Compressed Debug information" 319 help 320 Compress the resulting debug info. Results in smaller debug info sections, 321 but requires that consumers are able to decompress the results. 322 323 If unsure, choose DEBUG_INFO_COMPRESSED_NONE. 324 325config DEBUG_INFO_COMPRESSED_NONE 326 bool "Don't compress debug information" 327 help 328 Don't compress debug info sections. 329 330config DEBUG_INFO_COMPRESSED_ZLIB 331 bool "Compress debugging information with zlib" 332 depends on $(cc-option,-gz=zlib) 333 depends on $(ld-option,--compress-debug-sections=zlib) 334 help 335 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 336 5.0+, binutils 2.26+, and zlib. 337 338 Users of dpkg-deb via scripts/package/builddeb may find an increase in 339 size of their debug .deb packages with this config set, due to the 340 debug info being compressed with zlib, then the object files being 341 recompressed with a different compression scheme. But this is still 342 preferable to setting $KDEB_COMPRESS to "none" which would be even 343 larger. 344 345config DEBUG_INFO_COMPRESSED_ZSTD 346 bool "Compress debugging information with zstd" 347 depends on $(cc-option,-gz=zstd) 348 depends on $(ld-option,--compress-debug-sections=zstd) 349 help 350 Compress the debug information using zstd. This may provide better 351 compression than zlib, for about the same time costs, but requires newer 352 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and 353 zstd. 354 355endchoice # "Compressed Debug information" 356 357config DEBUG_INFO_SPLIT 358 bool "Produce split debuginfo in .dwo files" 359 depends on $(cc-option,-gsplit-dwarf) 360 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC 361 # prior to 12.x: 362 # https://github.com/llvm/llvm-project/issues/56642 363 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 364 depends on !RISCV || GCC_VERSION >= 120000 365 help 366 Generate debug info into separate .dwo files. This significantly 367 reduces the build directory size for builds with DEBUG_INFO, 368 because it stores the information only once on disk in .dwo 369 files instead of multiple times in object files and executables. 370 In addition the debug information is also compressed. 371 372 Requires recent gcc (4.7+) and recent gdb/binutils. 373 Any tool that packages or reads debug information would need 374 to know about the .dwo files and include them. 375 Incompatible with older versions of ccache. 376 377config DEBUG_INFO_BTF 378 bool "Generate BTF typeinfo" 379 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 380 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 381 depends on BPF_SYSCALL 382 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 383 help 384 Generate deduplicated BTF type information from DWARF debug info. 385 Turning this on expects presence of pahole tool, which will convert 386 DWARF type info into equivalent deduplicated BTF type info. 387 388config PAHOLE_HAS_SPLIT_BTF 389 def_bool PAHOLE_VERSION >= 119 390 391config PAHOLE_HAS_BTF_TAG 392 def_bool PAHOLE_VERSION >= 123 393 depends on CC_IS_CLANG 394 help 395 Decide whether pahole emits btf_tag attributes (btf_type_tag and 396 btf_decl_tag) or not. Currently only clang compiler implements 397 these attributes, so make the config depend on CC_IS_CLANG. 398 399config PAHOLE_HAS_LANG_EXCLUDE 400 def_bool PAHOLE_VERSION >= 124 401 help 402 Support for the --lang_exclude flag which makes pahole exclude 403 compilation units from the supplied language. Used in Kbuild to 404 omit Rust CUs which are not supported in version 1.24 of pahole, 405 otherwise it would emit malformed kernel and module binaries when 406 using DEBUG_INFO_BTF_MODULES. 407 408config DEBUG_INFO_BTF_MODULES 409 def_bool y 410 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 411 help 412 Generate compact split BTF type information for kernel modules. 413 414config MODULE_ALLOW_BTF_MISMATCH 415 bool "Allow loading modules with non-matching BTF type info" 416 depends on DEBUG_INFO_BTF_MODULES 417 help 418 For modules whose split BTF does not match vmlinux, load without 419 BTF rather than refusing to load. The default behavior with 420 module BTF enabled is to reject modules with such mismatches; 421 this option will still load module BTF where possible but ignore 422 it when a mismatch is found. 423 424config GDB_SCRIPTS 425 bool "Provide GDB scripts for kernel debugging" 426 help 427 This creates the required links to GDB helper scripts in the 428 build directory. If you load vmlinux into gdb, the helper 429 scripts will be automatically imported by gdb as well, and 430 additional functions are available to analyze a Linux kernel 431 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 432 for further details. 433 434endif # DEBUG_INFO 435 436config FRAME_WARN 437 int "Warn for stack frames larger than" 438 range 0 8192 439 default 0 if KMSAN 440 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 441 default 2048 if PARISC 442 default 1536 if (!64BIT && XTENSA) 443 default 1280 if KASAN && !64BIT 444 default 1024 if !64BIT 445 default 2048 if 64BIT 446 help 447 Tell the compiler to warn at build time for stack frames larger than this. 448 Setting this too low will cause a lot of warnings. 449 Setting it to 0 disables the warning. 450 451config STRIP_ASM_SYMS 452 bool "Strip assembler-generated symbols during link" 453 default n 454 help 455 Strip internal assembler-generated symbols during a link (symbols 456 that look like '.Lxxx') so they don't pollute the output of 457 get_wchan() and suchlike. 458 459config READABLE_ASM 460 bool "Generate readable assembler code" 461 depends on DEBUG_KERNEL 462 depends on CC_IS_GCC 463 help 464 Disable some compiler optimizations that tend to generate human unreadable 465 assembler output. This may make the kernel slightly slower, but it helps 466 to keep kernel developers who have to stare a lot at assembler listings 467 sane. 468 469config HEADERS_INSTALL 470 bool "Install uapi headers to usr/include" 471 depends on !UML 472 help 473 This option will install uapi headers (headers exported to user-space) 474 into the usr/include directory for use during the kernel build. 475 This is unneeded for building the kernel itself, but needed for some 476 user-space program samples. It is also needed by some features such 477 as uapi header sanity checks. 478 479config DEBUG_SECTION_MISMATCH 480 bool "Enable full Section mismatch analysis" 481 depends on CC_IS_GCC 482 help 483 The section mismatch analysis checks if there are illegal 484 references from one section to another section. 485 During linktime or runtime, some sections are dropped; 486 any use of code/data previously in these sections would 487 most likely result in an oops. 488 In the code, functions and variables are annotated with 489 __init,, etc. (see the full list in include/linux/init.h), 490 which results in the code/data being placed in specific sections. 491 The section mismatch analysis is always performed after a full 492 kernel build, and enabling this option causes the following 493 additional step to occur: 494 - Add the option -fno-inline-functions-called-once to gcc commands. 495 When inlining a function annotated with __init in a non-init 496 function, we would lose the section information and thus 497 the analysis would not catch the illegal reference. 498 This option tells gcc to inline less (but it does result in 499 a larger kernel). 500 501config SECTION_MISMATCH_WARN_ONLY 502 bool "Make section mismatch errors non-fatal" 503 default y 504 help 505 If you say N here, the build process will fail if there are any 506 section mismatch, instead of just throwing warnings. 507 508 If unsure, say Y. 509 510config DEBUG_FORCE_FUNCTION_ALIGN_64B 511 bool "Force all function address 64B aligned" 512 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390) 513 select FUNCTION_ALIGNMENT_64B 514 help 515 There are cases that a commit from one domain changes the function 516 address alignment of other domains, and cause magic performance 517 bump (regression or improvement). Enable this option will help to 518 verify if the bump is caused by function alignment changes, while 519 it will slightly increase the kernel size and affect icache usage. 520 521 It is mainly for debug and performance tuning use. 522 523# 524# Select this config option from the architecture Kconfig, if it 525# is preferred to always offer frame pointers as a config 526# option on the architecture (regardless of KERNEL_DEBUG): 527# 528config ARCH_WANT_FRAME_POINTERS 529 bool 530 531config FRAME_POINTER 532 bool "Compile the kernel with frame pointers" 533 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 534 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 535 help 536 If you say Y here the resulting kernel image will be slightly 537 larger and slower, but it gives very useful debugging information 538 in case of kernel bugs. (precise oopses/stacktraces/warnings) 539 540config OBJTOOL 541 bool 542 543config STACK_VALIDATION 544 bool "Compile-time stack metadata validation" 545 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 546 select OBJTOOL 547 default n 548 help 549 Validate frame pointer rules at compile-time. This helps ensure that 550 runtime stack traces are more reliable. 551 552 For more information, see 553 tools/objtool/Documentation/objtool.txt. 554 555config NOINSTR_VALIDATION 556 bool 557 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 558 select OBJTOOL 559 default y 560 561config VMLINUX_MAP 562 bool "Generate vmlinux.map file when linking" 563 depends on EXPERT 564 help 565 Selecting this option will pass "-Map=vmlinux.map" to ld 566 when linking vmlinux. That file can be useful for verifying 567 and debugging magic section games, and for seeing which 568 pieces of code get eliminated with 569 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 570 571config DEBUG_FORCE_WEAK_PER_CPU 572 bool "Force weak per-cpu definitions" 573 depends on DEBUG_KERNEL 574 help 575 s390 and alpha require percpu variables in modules to be 576 defined weak to work around addressing range issue which 577 puts the following two restrictions on percpu variable 578 definitions. 579 580 1. percpu symbols must be unique whether static or not 581 2. percpu variables can't be defined inside a function 582 583 To ensure that generic code follows the above rules, this 584 option forces all percpu variables to be defined as weak. 585 586endmenu # "Compiler options" 587 588menu "Generic Kernel Debugging Instruments" 589 590config MAGIC_SYSRQ 591 bool "Magic SysRq key" 592 depends on !UML 593 help 594 If you say Y here, you will have some control over the system even 595 if the system crashes for example during kernel debugging (e.g., you 596 will be able to flush the buffer cache to disk, reboot the system 597 immediately or dump some status information). This is accomplished 598 by pressing various keys while holding SysRq (Alt+PrintScreen). It 599 also works on a serial console (on PC hardware at least), if you 600 send a BREAK and then within 5 seconds a command keypress. The 601 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 602 Don't say Y unless you really know what this hack does. 603 604config MAGIC_SYSRQ_DEFAULT_ENABLE 605 hex "Enable magic SysRq key functions by default" 606 depends on MAGIC_SYSRQ 607 default 0x1 608 help 609 Specifies which SysRq key functions are enabled by default. 610 This may be set to 1 or 0 to enable or disable them all, or 611 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 612 613config MAGIC_SYSRQ_SERIAL 614 bool "Enable magic SysRq key over serial" 615 depends on MAGIC_SYSRQ 616 default y 617 help 618 Many embedded boards have a disconnected TTL level serial which can 619 generate some garbage that can lead to spurious false sysrq detects. 620 This option allows you to decide whether you want to enable the 621 magic SysRq key. 622 623config MAGIC_SYSRQ_SERIAL_SEQUENCE 624 string "Char sequence that enables magic SysRq over serial" 625 depends on MAGIC_SYSRQ_SERIAL 626 default "" 627 help 628 Specifies a sequence of characters that can follow BREAK to enable 629 SysRq on a serial console. 630 631 If unsure, leave an empty string and the option will not be enabled. 632 633config DEBUG_FS 634 bool "Debug Filesystem" 635 help 636 debugfs is a virtual file system that kernel developers use to put 637 debugging files into. Enable this option to be able to read and 638 write to these files. 639 640 For detailed documentation on the debugfs API, see 641 Documentation/filesystems/. 642 643 If unsure, say N. 644 645choice 646 prompt "Debugfs default access" 647 depends on DEBUG_FS 648 default DEBUG_FS_ALLOW_ALL 649 help 650 This selects the default access restrictions for debugfs. 651 It can be overridden with kernel command line option 652 debugfs=[on,no-mount,off]. The restrictions apply for API access 653 and filesystem registration. 654 655config DEBUG_FS_ALLOW_ALL 656 bool "Access normal" 657 help 658 No restrictions apply. Both API and filesystem registration 659 is on. This is the normal default operation. 660 661config DEBUG_FS_DISALLOW_MOUNT 662 bool "Do not register debugfs as filesystem" 663 help 664 The API is open but filesystem is not loaded. Clients can still do 665 their work and read with debug tools that do not need 666 debugfs filesystem. 667 668config DEBUG_FS_ALLOW_NONE 669 bool "No access" 670 help 671 Access is off. Clients get -PERM when trying to create nodes in 672 debugfs tree and debugfs is not registered as a filesystem. 673 Client can then back-off or continue without debugfs access. 674 675endchoice 676 677source "lib/Kconfig.kgdb" 678source "lib/Kconfig.ubsan" 679source "lib/Kconfig.kcsan" 680 681endmenu 682 683menu "Networking Debugging" 684 685source "net/Kconfig.debug" 686 687endmenu # "Networking Debugging" 688 689menu "Memory Debugging" 690 691source "mm/Kconfig.debug" 692 693config DEBUG_OBJECTS 694 bool "Debug object operations" 695 depends on DEBUG_KERNEL 696 help 697 If you say Y here, additional code will be inserted into the 698 kernel to track the life time of various objects and validate 699 the operations on those objects. 700 701config DEBUG_OBJECTS_SELFTEST 702 bool "Debug objects selftest" 703 depends on DEBUG_OBJECTS 704 help 705 This enables the selftest of the object debug code. 706 707config DEBUG_OBJECTS_FREE 708 bool "Debug objects in freed memory" 709 depends on DEBUG_OBJECTS 710 help 711 This enables checks whether a k/v free operation frees an area 712 which contains an object which has not been deactivated 713 properly. This can make kmalloc/kfree-intensive workloads 714 much slower. 715 716config DEBUG_OBJECTS_TIMERS 717 bool "Debug timer objects" 718 depends on DEBUG_OBJECTS 719 help 720 If you say Y here, additional code will be inserted into the 721 timer routines to track the life time of timer objects and 722 validate the timer operations. 723 724config DEBUG_OBJECTS_WORK 725 bool "Debug work objects" 726 depends on DEBUG_OBJECTS 727 help 728 If you say Y here, additional code will be inserted into the 729 work queue routines to track the life time of work objects and 730 validate the work operations. 731 732config DEBUG_OBJECTS_RCU_HEAD 733 bool "Debug RCU callbacks objects" 734 depends on DEBUG_OBJECTS 735 help 736 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 737 738config DEBUG_OBJECTS_PERCPU_COUNTER 739 bool "Debug percpu counter objects" 740 depends on DEBUG_OBJECTS 741 help 742 If you say Y here, additional code will be inserted into the 743 percpu counter routines to track the life time of percpu counter 744 objects and validate the percpu counter operations. 745 746config DEBUG_OBJECTS_ENABLE_DEFAULT 747 int "debug_objects bootup default value (0-1)" 748 range 0 1 749 default "1" 750 depends on DEBUG_OBJECTS 751 help 752 Debug objects boot parameter default value 753 754config SHRINKER_DEBUG 755 bool "Enable shrinker debugging support" 756 depends on DEBUG_FS 757 help 758 Say Y to enable the shrinker debugfs interface which provides 759 visibility into the kernel memory shrinkers subsystem. 760 Disable it to avoid an extra memory footprint. 761 762config DEBUG_STACK_USAGE 763 bool "Stack utilization instrumentation" 764 depends on DEBUG_KERNEL 765 help 766 Enables the display of the minimum amount of free stack which each 767 task has ever had available in the sysrq-T and sysrq-P debug output. 768 769 This option will slow down process creation somewhat. 770 771config SCHED_STACK_END_CHECK 772 bool "Detect stack corruption on calls to schedule()" 773 depends on DEBUG_KERNEL 774 default n 775 help 776 This option checks for a stack overrun on calls to schedule(). 777 If the stack end location is found to be over written always panic as 778 the content of the corrupted region can no longer be trusted. 779 This is to ensure no erroneous behaviour occurs which could result in 780 data corruption or a sporadic crash at a later stage once the region 781 is examined. The runtime overhead introduced is minimal. 782 783config ARCH_HAS_DEBUG_VM_PGTABLE 784 bool 785 help 786 An architecture should select this when it can successfully 787 build and run DEBUG_VM_PGTABLE. 788 789config DEBUG_VM_IRQSOFF 790 def_bool DEBUG_VM && !PREEMPT_RT 791 792config DEBUG_VM 793 bool "Debug VM" 794 depends on DEBUG_KERNEL 795 help 796 Enable this to turn on extended checks in the virtual-memory system 797 that may impact performance. 798 799 If unsure, say N. 800 801config DEBUG_VM_SHOOT_LAZIES 802 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation" 803 depends on DEBUG_VM 804 depends on MMU_LAZY_TLB_SHOOTDOWN 805 help 806 Enable additional IPIs that ensure lazy tlb mm references are removed 807 before the mm is freed. 808 809 If unsure, say N. 810 811config DEBUG_VM_MAPLE_TREE 812 bool "Debug VM maple trees" 813 depends on DEBUG_VM 814 select DEBUG_MAPLE_TREE 815 help 816 Enable VM maple tree debugging information and extra validations. 817 818 If unsure, say N. 819 820config DEBUG_VM_RB 821 bool "Debug VM red-black trees" 822 depends on DEBUG_VM 823 help 824 Enable VM red-black tree debugging information and extra validations. 825 826 If unsure, say N. 827 828config DEBUG_VM_PGFLAGS 829 bool "Debug page-flags operations" 830 depends on DEBUG_VM 831 help 832 Enables extra validation on page flags operations. 833 834 If unsure, say N. 835 836config DEBUG_VM_PGTABLE 837 bool "Debug arch page table for semantics compliance" 838 depends on MMU 839 depends on ARCH_HAS_DEBUG_VM_PGTABLE 840 default y if DEBUG_VM 841 help 842 This option provides a debug method which can be used to test 843 architecture page table helper functions on various platforms in 844 verifying if they comply with expected generic MM semantics. This 845 will help architecture code in making sure that any changes or 846 new additions of these helpers still conform to expected 847 semantics of the generic MM. Platforms will have to opt in for 848 this through ARCH_HAS_DEBUG_VM_PGTABLE. 849 850 If unsure, say N. 851 852config ARCH_HAS_DEBUG_VIRTUAL 853 bool 854 855config DEBUG_VIRTUAL 856 bool "Debug VM translations" 857 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 858 help 859 Enable some costly sanity checks in virtual to page code. This can 860 catch mistakes with virt_to_page() and friends. 861 862 If unsure, say N. 863 864config DEBUG_NOMMU_REGIONS 865 bool "Debug the global anon/private NOMMU mapping region tree" 866 depends on DEBUG_KERNEL && !MMU 867 help 868 This option causes the global tree of anonymous and private mapping 869 regions to be regularly checked for invalid topology. 870 871config DEBUG_MEMORY_INIT 872 bool "Debug memory initialisation" if EXPERT 873 default !EXPERT 874 help 875 Enable this for additional checks during memory initialisation. 876 The sanity checks verify aspects of the VM such as the memory model 877 and other information provided by the architecture. Verbose 878 information will be printed at KERN_DEBUG loglevel depending 879 on the mminit_loglevel= command-line option. 880 881 If unsure, say Y 882 883config MEMORY_NOTIFIER_ERROR_INJECT 884 tristate "Memory hotplug notifier error injection module" 885 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 886 help 887 This option provides the ability to inject artificial errors to 888 memory hotplug notifier chain callbacks. It is controlled through 889 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 890 891 If the notifier call chain should be failed with some events 892 notified, write the error code to "actions/<notifier event>/error". 893 894 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 895 896 # cd /sys/kernel/debug/notifier-error-inject/memory 897 # echo -12 > actions/MEM_GOING_OFFLINE/error 898 # echo offline > /sys/devices/system/memory/memoryXXX/state 899 bash: echo: write error: Cannot allocate memory 900 901 To compile this code as a module, choose M here: the module will 902 be called memory-notifier-error-inject. 903 904 If unsure, say N. 905 906config DEBUG_PER_CPU_MAPS 907 bool "Debug access to per_cpu maps" 908 depends on DEBUG_KERNEL 909 depends on SMP 910 help 911 Say Y to verify that the per_cpu map being accessed has 912 been set up. This adds a fair amount of code to kernel memory 913 and decreases performance. 914 915 Say N if unsure. 916 917config DEBUG_KMAP_LOCAL 918 bool "Debug kmap_local temporary mappings" 919 depends on DEBUG_KERNEL && KMAP_LOCAL 920 help 921 This option enables additional error checking for the kmap_local 922 infrastructure. Disable for production use. 923 924config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 925 bool 926 927config DEBUG_KMAP_LOCAL_FORCE_MAP 928 bool "Enforce kmap_local temporary mappings" 929 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 930 select KMAP_LOCAL 931 select DEBUG_KMAP_LOCAL 932 help 933 This option enforces temporary mappings through the kmap_local 934 mechanism for non-highmem pages and on non-highmem systems. 935 Disable this for production systems! 936 937config DEBUG_HIGHMEM 938 bool "Highmem debugging" 939 depends on DEBUG_KERNEL && HIGHMEM 940 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 941 select DEBUG_KMAP_LOCAL 942 help 943 This option enables additional error checking for high memory 944 systems. Disable for production systems. 945 946config HAVE_DEBUG_STACKOVERFLOW 947 bool 948 949config DEBUG_STACKOVERFLOW 950 bool "Check for stack overflows" 951 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 952 help 953 Say Y here if you want to check for overflows of kernel, IRQ 954 and exception stacks (if your architecture uses them). This 955 option will show detailed messages if free stack space drops 956 below a certain limit. 957 958 These kinds of bugs usually occur when call-chains in the 959 kernel get too deep, especially when interrupts are 960 involved. 961 962 Use this in cases where you see apparently random memory 963 corruption, especially if it appears in 'struct thread_info' 964 965 If in doubt, say "N". 966 967source "lib/Kconfig.kasan" 968source "lib/Kconfig.kfence" 969source "lib/Kconfig.kmsan" 970 971endmenu # "Memory Debugging" 972 973config DEBUG_SHIRQ 974 bool "Debug shared IRQ handlers" 975 depends on DEBUG_KERNEL 976 help 977 Enable this to generate a spurious interrupt just before a shared 978 interrupt handler is deregistered (generating one when registering 979 is currently disabled). Drivers need to handle this correctly. Some 980 don't and need to be caught. 981 982menu "Debug Oops, Lockups and Hangs" 983 984config PANIC_ON_OOPS 985 bool "Panic on Oops" 986 help 987 Say Y here to enable the kernel to panic when it oopses. This 988 has the same effect as setting oops=panic on the kernel command 989 line. 990 991 This feature is useful to ensure that the kernel does not do 992 anything erroneous after an oops which could result in data 993 corruption or other issues. 994 995 Say N if unsure. 996 997config PANIC_ON_OOPS_VALUE 998 int 999 range 0 1 1000 default 0 if !PANIC_ON_OOPS 1001 default 1 if PANIC_ON_OOPS 1002 1003config PANIC_TIMEOUT 1004 int "panic timeout" 1005 default 0 1006 help 1007 Set the timeout value (in seconds) until a reboot occurs when 1008 the kernel panics. If n = 0, then we wait forever. A timeout 1009 value n > 0 will wait n seconds before rebooting, while a timeout 1010 value n < 0 will reboot immediately. 1011 1012config LOCKUP_DETECTOR 1013 bool 1014 1015config SOFTLOCKUP_DETECTOR 1016 bool "Detect Soft Lockups" 1017 depends on DEBUG_KERNEL && !S390 1018 select LOCKUP_DETECTOR 1019 help 1020 Say Y here to enable the kernel to act as a watchdog to detect 1021 soft lockups. 1022 1023 Softlockups are bugs that cause the kernel to loop in kernel 1024 mode for more than 20 seconds, without giving other tasks a 1025 chance to run. The current stack trace is displayed upon 1026 detection and the system will stay locked up. 1027 1028config BOOTPARAM_SOFTLOCKUP_PANIC 1029 bool "Panic (Reboot) On Soft Lockups" 1030 depends on SOFTLOCKUP_DETECTOR 1031 help 1032 Say Y here to enable the kernel to panic on "soft lockups", 1033 which are bugs that cause the kernel to loop in kernel 1034 mode for more than 20 seconds (configurable using the watchdog_thresh 1035 sysctl), without giving other tasks a chance to run. 1036 1037 The panic can be used in combination with panic_timeout, 1038 to cause the system to reboot automatically after a 1039 lockup has been detected. This feature is useful for 1040 high-availability systems that have uptime guarantees and 1041 where a lockup must be resolved ASAP. 1042 1043 Say N if unsure. 1044 1045config HAVE_HARDLOCKUP_DETECTOR_BUDDY 1046 bool 1047 depends on SMP 1048 default y 1049 1050# 1051# Global switch whether to build a hardlockup detector at all. It is available 1052# only when the architecture supports at least one implementation. There are 1053# two exceptions. The hardlockup detector is never enabled on: 1054# 1055# s390: it reported many false positives there 1056# 1057# sparc64: has a custom implementation which is not using the common 1058# hardlockup command line options and sysctl interface. 1059# 1060config HARDLOCKUP_DETECTOR 1061 bool "Detect Hard Lockups" 1062 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64 1063 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH 1064 imply HARDLOCKUP_DETECTOR_PERF 1065 imply HARDLOCKUP_DETECTOR_BUDDY 1066 imply HARDLOCKUP_DETECTOR_ARCH 1067 select LOCKUP_DETECTOR 1068 1069 help 1070 Say Y here to enable the kernel to act as a watchdog to detect 1071 hard lockups. 1072 1073 Hardlockups are bugs that cause the CPU to loop in kernel mode 1074 for more than 10 seconds, without letting other interrupts have a 1075 chance to run. The current stack trace is displayed upon detection 1076 and the system will stay locked up. 1077 1078# 1079# Note that arch-specific variants are always preferred. 1080# 1081config HARDLOCKUP_DETECTOR_PREFER_BUDDY 1082 bool "Prefer the buddy CPU hardlockup detector" 1083 depends on HARDLOCKUP_DETECTOR 1084 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY 1085 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1086 help 1087 Say Y here to prefer the buddy hardlockup detector over the perf one. 1088 1089 With the buddy detector, each CPU uses its softlockup hrtimer 1090 to check that the next CPU is processing hrtimer interrupts by 1091 verifying that a counter is increasing. 1092 1093 This hardlockup detector is useful on systems that don't have 1094 an arch-specific hardlockup detector or if resources needed 1095 for the hardlockup detector are better used for other things. 1096 1097config HARDLOCKUP_DETECTOR_PERF 1098 bool 1099 depends on HARDLOCKUP_DETECTOR 1100 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY 1101 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1102 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1103 1104config HARDLOCKUP_DETECTOR_BUDDY 1105 bool 1106 depends on HARDLOCKUP_DETECTOR 1107 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY 1108 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY 1109 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1110 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1111 1112config HARDLOCKUP_DETECTOR_ARCH 1113 bool 1114 depends on HARDLOCKUP_DETECTOR 1115 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH 1116 help 1117 The arch-specific implementation of the hardlockup detector will 1118 be used. 1119 1120# 1121# Both the "perf" and "buddy" hardlockup detectors count hrtimer 1122# interrupts. This config enables functions managing this common code. 1123# 1124config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1125 bool 1126 select SOFTLOCKUP_DETECTOR 1127 1128# 1129# Enables a timestamp based low pass filter to compensate for perf based 1130# hard lockup detection which runs too fast due to turbo modes. 1131# 1132config HARDLOCKUP_CHECK_TIMESTAMP 1133 bool 1134 1135config BOOTPARAM_HARDLOCKUP_PANIC 1136 bool "Panic (Reboot) On Hard Lockups" 1137 depends on HARDLOCKUP_DETECTOR 1138 help 1139 Say Y here to enable the kernel to panic on "hard lockups", 1140 which are bugs that cause the kernel to loop in kernel 1141 mode with interrupts disabled for more than 10 seconds (configurable 1142 using the watchdog_thresh sysctl). 1143 1144 Say N if unsure. 1145 1146config DETECT_HUNG_TASK 1147 bool "Detect Hung Tasks" 1148 depends on DEBUG_KERNEL 1149 default SOFTLOCKUP_DETECTOR 1150 help 1151 Say Y here to enable the kernel to detect "hung tasks", 1152 which are bugs that cause the task to be stuck in 1153 uninterruptible "D" state indefinitely. 1154 1155 When a hung task is detected, the kernel will print the 1156 current stack trace (which you should report), but the 1157 task will stay in uninterruptible state. If lockdep is 1158 enabled then all held locks will also be reported. This 1159 feature has negligible overhead. 1160 1161config DEFAULT_HUNG_TASK_TIMEOUT 1162 int "Default timeout for hung task detection (in seconds)" 1163 depends on DETECT_HUNG_TASK 1164 default 120 1165 help 1166 This option controls the default timeout (in seconds) used 1167 to determine when a task has become non-responsive and should 1168 be considered hung. 1169 1170 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1171 sysctl or by writing a value to 1172 /proc/sys/kernel/hung_task_timeout_secs. 1173 1174 A timeout of 0 disables the check. The default is two minutes. 1175 Keeping the default should be fine in most cases. 1176 1177config BOOTPARAM_HUNG_TASK_PANIC 1178 bool "Panic (Reboot) On Hung Tasks" 1179 depends on DETECT_HUNG_TASK 1180 help 1181 Say Y here to enable the kernel to panic on "hung tasks", 1182 which are bugs that cause the kernel to leave a task stuck 1183 in uninterruptible "D" state. 1184 1185 The panic can be used in combination with panic_timeout, 1186 to cause the system to reboot automatically after a 1187 hung task has been detected. This feature is useful for 1188 high-availability systems that have uptime guarantees and 1189 where a hung tasks must be resolved ASAP. 1190 1191 Say N if unsure. 1192 1193config WQ_WATCHDOG 1194 bool "Detect Workqueue Stalls" 1195 depends on DEBUG_KERNEL 1196 help 1197 Say Y here to enable stall detection on workqueues. If a 1198 worker pool doesn't make forward progress on a pending work 1199 item for over a given amount of time, 30s by default, a 1200 warning message is printed along with dump of workqueue 1201 state. This can be configured through kernel parameter 1202 "workqueue.watchdog_thresh" and its sysfs counterpart. 1203 1204config WQ_CPU_INTENSIVE_REPORT 1205 bool "Report per-cpu work items which hog CPU for too long" 1206 depends on DEBUG_KERNEL 1207 help 1208 Say Y here to enable reporting of concurrency-managed per-cpu work 1209 items that hog CPUs for longer than 1210 workqueue.cpu_intensive_thresh_us. Workqueue automatically 1211 detects and excludes them from concurrency management to prevent 1212 them from stalling other per-cpu work items. Occassional 1213 triggering may not necessarily indicate a problem. Repeated 1214 triggering likely indicates that the work item should be switched 1215 to use an unbound workqueue. 1216 1217config TEST_LOCKUP 1218 tristate "Test module to generate lockups" 1219 depends on m 1220 help 1221 This builds the "test_lockup" module that helps to make sure 1222 that watchdogs and lockup detectors are working properly. 1223 1224 Depending on module parameters it could emulate soft or hard 1225 lockup, "hung task", or locking arbitrary lock for a long time. 1226 Also it could generate series of lockups with cooling-down periods. 1227 1228 If unsure, say N. 1229 1230endmenu # "Debug lockups and hangs" 1231 1232menu "Scheduler Debugging" 1233 1234config SCHED_DEBUG 1235 bool "Collect scheduler debugging info" 1236 depends on DEBUG_KERNEL && DEBUG_FS 1237 default y 1238 help 1239 If you say Y here, the /sys/kernel/debug/sched file will be provided 1240 that can help debug the scheduler. The runtime overhead of this 1241 option is minimal. 1242 1243config SCHED_INFO 1244 bool 1245 default n 1246 1247config SCHEDSTATS 1248 bool "Collect scheduler statistics" 1249 depends on DEBUG_KERNEL && PROC_FS 1250 select SCHED_INFO 1251 help 1252 If you say Y here, additional code will be inserted into the 1253 scheduler and related routines to collect statistics about 1254 scheduler behavior and provide them in /proc/schedstat. These 1255 stats may be useful for both tuning and debugging the scheduler 1256 If you aren't debugging the scheduler or trying to tune a specific 1257 application, you can say N to avoid the very slight overhead 1258 this adds. 1259 1260endmenu 1261 1262config DEBUG_TIMEKEEPING 1263 bool "Enable extra timekeeping sanity checking" 1264 help 1265 This option will enable additional timekeeping sanity checks 1266 which may be helpful when diagnosing issues where timekeeping 1267 problems are suspected. 1268 1269 This may include checks in the timekeeping hotpaths, so this 1270 option may have a (very small) performance impact to some 1271 workloads. 1272 1273 If unsure, say N. 1274 1275config DEBUG_PREEMPT 1276 bool "Debug preemptible kernel" 1277 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1278 help 1279 If you say Y here then the kernel will use a debug variant of the 1280 commonly used smp_processor_id() function and will print warnings 1281 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1282 will detect preemption count underflows. 1283 1284 This option has potential to introduce high runtime overhead, 1285 depending on workload as it triggers debugging routines for each 1286 this_cpu operation. It should only be used for debugging purposes. 1287 1288menu "Lock Debugging (spinlocks, mutexes, etc...)" 1289 1290config LOCK_DEBUGGING_SUPPORT 1291 bool 1292 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1293 default y 1294 1295config PROVE_LOCKING 1296 bool "Lock debugging: prove locking correctness" 1297 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1298 select LOCKDEP 1299 select DEBUG_SPINLOCK 1300 select DEBUG_MUTEXES if !PREEMPT_RT 1301 select DEBUG_RT_MUTEXES if RT_MUTEXES 1302 select DEBUG_RWSEMS 1303 select DEBUG_WW_MUTEX_SLOWPATH 1304 select DEBUG_LOCK_ALLOC 1305 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1306 select TRACE_IRQFLAGS 1307 default n 1308 help 1309 This feature enables the kernel to prove that all locking 1310 that occurs in the kernel runtime is mathematically 1311 correct: that under no circumstance could an arbitrary (and 1312 not yet triggered) combination of observed locking 1313 sequences (on an arbitrary number of CPUs, running an 1314 arbitrary number of tasks and interrupt contexts) cause a 1315 deadlock. 1316 1317 In short, this feature enables the kernel to report locking 1318 related deadlocks before they actually occur. 1319 1320 The proof does not depend on how hard and complex a 1321 deadlock scenario would be to trigger: how many 1322 participant CPUs, tasks and irq-contexts would be needed 1323 for it to trigger. The proof also does not depend on 1324 timing: if a race and a resulting deadlock is possible 1325 theoretically (no matter how unlikely the race scenario 1326 is), it will be proven so and will immediately be 1327 reported by the kernel (once the event is observed that 1328 makes the deadlock theoretically possible). 1329 1330 If a deadlock is impossible (i.e. the locking rules, as 1331 observed by the kernel, are mathematically correct), the 1332 kernel reports nothing. 1333 1334 NOTE: this feature can also be enabled for rwlocks, mutexes 1335 and rwsems - in which case all dependencies between these 1336 different locking variants are observed and mapped too, and 1337 the proof of observed correctness is also maintained for an 1338 arbitrary combination of these separate locking variants. 1339 1340 For more details, see Documentation/locking/lockdep-design.rst. 1341 1342config PROVE_RAW_LOCK_NESTING 1343 bool "Enable raw_spinlock - spinlock nesting checks" 1344 depends on PROVE_LOCKING 1345 default n 1346 help 1347 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1348 that the lock nesting rules for PREEMPT_RT enabled kernels are 1349 not violated. 1350 1351 NOTE: There are known nesting problems. So if you enable this 1352 option expect lockdep splats until these problems have been fully 1353 addressed which is work in progress. This config switch allows to 1354 identify and analyze these problems. It will be removed and the 1355 check permanently enabled once the main issues have been fixed. 1356 1357 If unsure, select N. 1358 1359config LOCK_STAT 1360 bool "Lock usage statistics" 1361 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1362 select LOCKDEP 1363 select DEBUG_SPINLOCK 1364 select DEBUG_MUTEXES if !PREEMPT_RT 1365 select DEBUG_RT_MUTEXES if RT_MUTEXES 1366 select DEBUG_LOCK_ALLOC 1367 default n 1368 help 1369 This feature enables tracking lock contention points 1370 1371 For more details, see Documentation/locking/lockstat.rst 1372 1373 This also enables lock events required by "perf lock", 1374 subcommand of perf. 1375 If you want to use "perf lock", you also need to turn on 1376 CONFIG_EVENT_TRACING. 1377 1378 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1379 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1380 1381config DEBUG_RT_MUTEXES 1382 bool "RT Mutex debugging, deadlock detection" 1383 depends on DEBUG_KERNEL && RT_MUTEXES 1384 help 1385 This allows rt mutex semantics violations and rt mutex related 1386 deadlocks (lockups) to be detected and reported automatically. 1387 1388config DEBUG_SPINLOCK 1389 bool "Spinlock and rw-lock debugging: basic checks" 1390 depends on DEBUG_KERNEL 1391 select UNINLINE_SPIN_UNLOCK 1392 help 1393 Say Y here and build SMP to catch missing spinlock initialization 1394 and certain other kinds of spinlock errors commonly made. This is 1395 best used in conjunction with the NMI watchdog so that spinlock 1396 deadlocks are also debuggable. 1397 1398config DEBUG_MUTEXES 1399 bool "Mutex debugging: basic checks" 1400 depends on DEBUG_KERNEL && !PREEMPT_RT 1401 help 1402 This feature allows mutex semantics violations to be detected and 1403 reported. 1404 1405config DEBUG_WW_MUTEX_SLOWPATH 1406 bool "Wait/wound mutex debugging: Slowpath testing" 1407 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1408 select DEBUG_LOCK_ALLOC 1409 select DEBUG_SPINLOCK 1410 select DEBUG_MUTEXES if !PREEMPT_RT 1411 select DEBUG_RT_MUTEXES if PREEMPT_RT 1412 help 1413 This feature enables slowpath testing for w/w mutex users by 1414 injecting additional -EDEADLK wound/backoff cases. Together with 1415 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1416 will test all possible w/w mutex interface abuse with the 1417 exception of simply not acquiring all the required locks. 1418 Note that this feature can introduce significant overhead, so 1419 it really should not be enabled in a production or distro kernel, 1420 even a debug kernel. If you are a driver writer, enable it. If 1421 you are a distro, do not. 1422 1423config DEBUG_RWSEMS 1424 bool "RW Semaphore debugging: basic checks" 1425 depends on DEBUG_KERNEL 1426 help 1427 This debugging feature allows mismatched rw semaphore locks 1428 and unlocks to be detected and reported. 1429 1430config DEBUG_LOCK_ALLOC 1431 bool "Lock debugging: detect incorrect freeing of live locks" 1432 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1433 select DEBUG_SPINLOCK 1434 select DEBUG_MUTEXES if !PREEMPT_RT 1435 select DEBUG_RT_MUTEXES if RT_MUTEXES 1436 select LOCKDEP 1437 help 1438 This feature will check whether any held lock (spinlock, rwlock, 1439 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1440 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1441 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1442 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1443 held during task exit. 1444 1445config LOCKDEP 1446 bool 1447 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1448 select STACKTRACE 1449 select KALLSYMS 1450 select KALLSYMS_ALL 1451 1452config LOCKDEP_SMALL 1453 bool 1454 1455config LOCKDEP_BITS 1456 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1457 depends on LOCKDEP && !LOCKDEP_SMALL 1458 range 10 30 1459 default 15 1460 help 1461 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1462 1463config LOCKDEP_CHAINS_BITS 1464 int "Bitsize for MAX_LOCKDEP_CHAINS" 1465 depends on LOCKDEP && !LOCKDEP_SMALL 1466 range 10 30 1467 default 16 1468 help 1469 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1470 1471config LOCKDEP_STACK_TRACE_BITS 1472 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1473 depends on LOCKDEP && !LOCKDEP_SMALL 1474 range 10 30 1475 default 19 1476 help 1477 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1478 1479config LOCKDEP_STACK_TRACE_HASH_BITS 1480 int "Bitsize for STACK_TRACE_HASH_SIZE" 1481 depends on LOCKDEP && !LOCKDEP_SMALL 1482 range 10 30 1483 default 14 1484 help 1485 Try increasing this value if you need large STACK_TRACE_HASH_SIZE. 1486 1487config LOCKDEP_CIRCULAR_QUEUE_BITS 1488 int "Bitsize for elements in circular_queue struct" 1489 depends on LOCKDEP 1490 range 10 30 1491 default 12 1492 help 1493 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1494 1495config DEBUG_LOCKDEP 1496 bool "Lock dependency engine debugging" 1497 depends on DEBUG_KERNEL && LOCKDEP 1498 select DEBUG_IRQFLAGS 1499 help 1500 If you say Y here, the lock dependency engine will do 1501 additional runtime checks to debug itself, at the price 1502 of more runtime overhead. 1503 1504config DEBUG_ATOMIC_SLEEP 1505 bool "Sleep inside atomic section checking" 1506 select PREEMPT_COUNT 1507 depends on DEBUG_KERNEL 1508 depends on !ARCH_NO_PREEMPT 1509 help 1510 If you say Y here, various routines which may sleep will become very 1511 noisy if they are called inside atomic sections: when a spinlock is 1512 held, inside an rcu read side critical section, inside preempt disabled 1513 sections, inside an interrupt, etc... 1514 1515config DEBUG_LOCKING_API_SELFTESTS 1516 bool "Locking API boot-time self-tests" 1517 depends on DEBUG_KERNEL 1518 help 1519 Say Y here if you want the kernel to run a short self-test during 1520 bootup. The self-test checks whether common types of locking bugs 1521 are detected by debugging mechanisms or not. (if you disable 1522 lock debugging then those bugs won't be detected of course.) 1523 The following locking APIs are covered: spinlocks, rwlocks, 1524 mutexes and rwsems. 1525 1526config LOCK_TORTURE_TEST 1527 tristate "torture tests for locking" 1528 depends on DEBUG_KERNEL 1529 select TORTURE_TEST 1530 help 1531 This option provides a kernel module that runs torture tests 1532 on kernel locking primitives. The kernel module may be built 1533 after the fact on the running kernel to be tested, if desired. 1534 1535 Say Y here if you want kernel locking-primitive torture tests 1536 to be built into the kernel. 1537 Say M if you want these torture tests to build as a module. 1538 Say N if you are unsure. 1539 1540config WW_MUTEX_SELFTEST 1541 tristate "Wait/wound mutex selftests" 1542 help 1543 This option provides a kernel module that runs tests on the 1544 on the struct ww_mutex locking API. 1545 1546 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1547 with this test harness. 1548 1549 Say M if you want these self tests to build as a module. 1550 Say N if you are unsure. 1551 1552config SCF_TORTURE_TEST 1553 tristate "torture tests for smp_call_function*()" 1554 depends on DEBUG_KERNEL 1555 select TORTURE_TEST 1556 help 1557 This option provides a kernel module that runs torture tests 1558 on the smp_call_function() family of primitives. The kernel 1559 module may be built after the fact on the running kernel to 1560 be tested, if desired. 1561 1562config CSD_LOCK_WAIT_DEBUG 1563 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1564 depends on DEBUG_KERNEL 1565 depends on 64BIT 1566 default n 1567 help 1568 This option enables debug prints when CPUs are slow to respond 1569 to the smp_call_function*() IPI wrappers. These debug prints 1570 include the IPI handler function currently executing (if any) 1571 and relevant stack traces. 1572 1573config CSD_LOCK_WAIT_DEBUG_DEFAULT 1574 bool "Default csd_lock_wait() debugging on at boot time" 1575 depends on CSD_LOCK_WAIT_DEBUG 1576 depends on 64BIT 1577 default n 1578 help 1579 This option causes the csdlock_debug= kernel boot parameter to 1580 default to 1 (basic debugging) instead of 0 (no debugging). 1581 1582endmenu # lock debugging 1583 1584config TRACE_IRQFLAGS 1585 depends on TRACE_IRQFLAGS_SUPPORT 1586 bool 1587 help 1588 Enables hooks to interrupt enabling and disabling for 1589 either tracing or lock debugging. 1590 1591config TRACE_IRQFLAGS_NMI 1592 def_bool y 1593 depends on TRACE_IRQFLAGS 1594 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1595 1596config NMI_CHECK_CPU 1597 bool "Debugging for CPUs failing to respond to backtrace requests" 1598 depends on DEBUG_KERNEL 1599 depends on X86 1600 default n 1601 help 1602 Enables debug prints when a CPU fails to respond to a given 1603 backtrace NMI. These prints provide some reasons why a CPU 1604 might legitimately be failing to respond, for example, if it 1605 is offline of if ignore_nmis is set. 1606 1607config DEBUG_IRQFLAGS 1608 bool "Debug IRQ flag manipulation" 1609 help 1610 Enables checks for potentially unsafe enabling or disabling of 1611 interrupts, such as calling raw_local_irq_restore() when interrupts 1612 are enabled. 1613 1614config STACKTRACE 1615 bool "Stack backtrace support" 1616 depends on STACKTRACE_SUPPORT 1617 help 1618 This option causes the kernel to create a /proc/pid/stack for 1619 every process, showing its current stack trace. 1620 It is also used by various kernel debugging features that require 1621 stack trace generation. 1622 1623config WARN_ALL_UNSEEDED_RANDOM 1624 bool "Warn for all uses of unseeded randomness" 1625 default n 1626 help 1627 Some parts of the kernel contain bugs relating to their use of 1628 cryptographically secure random numbers before it's actually possible 1629 to generate those numbers securely. This setting ensures that these 1630 flaws don't go unnoticed, by enabling a message, should this ever 1631 occur. This will allow people with obscure setups to know when things 1632 are going wrong, so that they might contact developers about fixing 1633 it. 1634 1635 Unfortunately, on some models of some architectures getting 1636 a fully seeded CRNG is extremely difficult, and so this can 1637 result in dmesg getting spammed for a surprisingly long 1638 time. This is really bad from a security perspective, and 1639 so architecture maintainers really need to do what they can 1640 to get the CRNG seeded sooner after the system is booted. 1641 However, since users cannot do anything actionable to 1642 address this, by default this option is disabled. 1643 1644 Say Y here if you want to receive warnings for all uses of 1645 unseeded randomness. This will be of use primarily for 1646 those developers interested in improving the security of 1647 Linux kernels running on their architecture (or 1648 subarchitecture). 1649 1650config DEBUG_KOBJECT 1651 bool "kobject debugging" 1652 depends on DEBUG_KERNEL 1653 help 1654 If you say Y here, some extra kobject debugging messages will be sent 1655 to the syslog. 1656 1657config DEBUG_KOBJECT_RELEASE 1658 bool "kobject release debugging" 1659 depends on DEBUG_OBJECTS_TIMERS 1660 help 1661 kobjects are reference counted objects. This means that their 1662 last reference count put is not predictable, and the kobject can 1663 live on past the point at which a driver decides to drop its 1664 initial reference to the kobject gained on allocation. An 1665 example of this would be a struct device which has just been 1666 unregistered. 1667 1668 However, some buggy drivers assume that after such an operation, 1669 the memory backing the kobject can be immediately freed. This 1670 goes completely against the principles of a refcounted object. 1671 1672 If you say Y here, the kernel will delay the release of kobjects 1673 on the last reference count to improve the visibility of this 1674 kind of kobject release bug. 1675 1676config HAVE_DEBUG_BUGVERBOSE 1677 bool 1678 1679menu "Debug kernel data structures" 1680 1681config DEBUG_LIST 1682 bool "Debug linked list manipulation" 1683 depends on DEBUG_KERNEL 1684 select LIST_HARDENED 1685 help 1686 Enable this to turn on extended checks in the linked-list walking 1687 routines. 1688 1689 This option trades better quality error reports for performance, and 1690 is more suitable for kernel debugging. If you care about performance, 1691 you should only enable CONFIG_LIST_HARDENED instead. 1692 1693 If unsure, say N. 1694 1695config DEBUG_PLIST 1696 bool "Debug priority linked list manipulation" 1697 depends on DEBUG_KERNEL 1698 help 1699 Enable this to turn on extended checks in the priority-ordered 1700 linked-list (plist) walking routines. This checks the entire 1701 list multiple times during each manipulation. 1702 1703 If unsure, say N. 1704 1705config DEBUG_SG 1706 bool "Debug SG table operations" 1707 depends on DEBUG_KERNEL 1708 help 1709 Enable this to turn on checks on scatter-gather tables. This can 1710 help find problems with drivers that do not properly initialize 1711 their sg tables. 1712 1713 If unsure, say N. 1714 1715config DEBUG_NOTIFIERS 1716 bool "Debug notifier call chains" 1717 depends on DEBUG_KERNEL 1718 help 1719 Enable this to turn on sanity checking for notifier call chains. 1720 This is most useful for kernel developers to make sure that 1721 modules properly unregister themselves from notifier chains. 1722 This is a relatively cheap check but if you care about maximum 1723 performance, say N. 1724 1725config DEBUG_CLOSURES 1726 bool "Debug closures (bcache async widgits)" 1727 depends on CLOSURES 1728 select DEBUG_FS 1729 help 1730 Keeps all active closures in a linked list and provides a debugfs 1731 interface to list them, which makes it possible to see asynchronous 1732 operations that get stuck. 1733 1734config DEBUG_MAPLE_TREE 1735 bool "Debug maple trees" 1736 depends on DEBUG_KERNEL 1737 help 1738 Enable maple tree debugging information and extra validations. 1739 1740 If unsure, say N. 1741 1742endmenu 1743 1744config DEBUG_CREDENTIALS 1745 bool "Debug credential management" 1746 depends on DEBUG_KERNEL 1747 help 1748 Enable this to turn on some debug checking for credential 1749 management. The additional code keeps track of the number of 1750 pointers from task_structs to any given cred struct, and checks to 1751 see that this number never exceeds the usage count of the cred 1752 struct. 1753 1754 Furthermore, if SELinux is enabled, this also checks that the 1755 security pointer in the cred struct is never seen to be invalid. 1756 1757 If unsure, say N. 1758 1759source "kernel/rcu/Kconfig.debug" 1760 1761config DEBUG_WQ_FORCE_RR_CPU 1762 bool "Force round-robin CPU selection for unbound work items" 1763 depends on DEBUG_KERNEL 1764 default n 1765 help 1766 Workqueue used to implicitly guarantee that work items queued 1767 without explicit CPU specified are put on the local CPU. This 1768 guarantee is no longer true and while local CPU is still 1769 preferred work items may be put on foreign CPUs. Kernel 1770 parameter "workqueue.debug_force_rr_cpu" is added to force 1771 round-robin CPU selection to flush out usages which depend on the 1772 now broken guarantee. This config option enables the debug 1773 feature by default. When enabled, memory and cache locality will 1774 be impacted. 1775 1776config CPU_HOTPLUG_STATE_CONTROL 1777 bool "Enable CPU hotplug state control" 1778 depends on DEBUG_KERNEL 1779 depends on HOTPLUG_CPU 1780 default n 1781 help 1782 Allows to write steps between "offline" and "online" to the CPUs 1783 sysfs target file so states can be stepped granular. This is a debug 1784 option for now as the hotplug machinery cannot be stopped and 1785 restarted at arbitrary points yet. 1786 1787 Say N if your are unsure. 1788 1789config LATENCYTOP 1790 bool "Latency measuring infrastructure" 1791 depends on DEBUG_KERNEL 1792 depends on STACKTRACE_SUPPORT 1793 depends on PROC_FS 1794 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1795 select KALLSYMS 1796 select KALLSYMS_ALL 1797 select STACKTRACE 1798 select SCHEDSTATS 1799 help 1800 Enable this option if you want to use the LatencyTOP tool 1801 to find out which userspace is blocking on what kernel operations. 1802 1803config DEBUG_CGROUP_REF 1804 bool "Disable inlining of cgroup css reference count functions" 1805 depends on DEBUG_KERNEL 1806 depends on CGROUPS 1807 depends on KPROBES 1808 default n 1809 help 1810 Force cgroup css reference count functions to not be inlined so 1811 that they can be kprobed for debugging. 1812 1813source "kernel/trace/Kconfig" 1814 1815config PROVIDE_OHCI1394_DMA_INIT 1816 bool "Remote debugging over FireWire early on boot" 1817 depends on PCI && X86 1818 help 1819 If you want to debug problems which hang or crash the kernel early 1820 on boot and the crashing machine has a FireWire port, you can use 1821 this feature to remotely access the memory of the crashed machine 1822 over FireWire. This employs remote DMA as part of the OHCI1394 1823 specification which is now the standard for FireWire controllers. 1824 1825 With remote DMA, you can monitor the printk buffer remotely using 1826 firescope and access all memory below 4GB using fireproxy from gdb. 1827 Even controlling a kernel debugger is possible using remote DMA. 1828 1829 Usage: 1830 1831 If ohci1394_dma=early is used as boot parameter, it will initialize 1832 all OHCI1394 controllers which are found in the PCI config space. 1833 1834 As all changes to the FireWire bus such as enabling and disabling 1835 devices cause a bus reset and thereby disable remote DMA for all 1836 devices, be sure to have the cable plugged and FireWire enabled on 1837 the debugging host before booting the debug target for debugging. 1838 1839 This code (~1k) is freed after boot. By then, the firewire stack 1840 in charge of the OHCI-1394 controllers should be used instead. 1841 1842 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1843 1844source "samples/Kconfig" 1845 1846config ARCH_HAS_DEVMEM_IS_ALLOWED 1847 bool 1848 1849config STRICT_DEVMEM 1850 bool "Filter access to /dev/mem" 1851 depends on MMU && DEVMEM 1852 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1853 default y if PPC || X86 || ARM64 1854 help 1855 If this option is disabled, you allow userspace (root) access to all 1856 of memory, including kernel and userspace memory. Accidental 1857 access to this is obviously disastrous, but specific access can 1858 be used by people debugging the kernel. Note that with PAT support 1859 enabled, even in this case there are restrictions on /dev/mem 1860 use due to the cache aliasing requirements. 1861 1862 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1863 file only allows userspace access to PCI space and the BIOS code and 1864 data regions. This is sufficient for dosemu and X and all common 1865 users of /dev/mem. 1866 1867 If in doubt, say Y. 1868 1869config IO_STRICT_DEVMEM 1870 bool "Filter I/O access to /dev/mem" 1871 depends on STRICT_DEVMEM 1872 help 1873 If this option is disabled, you allow userspace (root) access to all 1874 io-memory regardless of whether a driver is actively using that 1875 range. Accidental access to this is obviously disastrous, but 1876 specific access can be used by people debugging kernel drivers. 1877 1878 If this option is switched on, the /dev/mem file only allows 1879 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1880 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1881 if the driver using a given range cannot be disabled. 1882 1883 If in doubt, say Y. 1884 1885menu "$(SRCARCH) Debugging" 1886 1887source "arch/$(SRCARCH)/Kconfig.debug" 1888 1889endmenu 1890 1891menu "Kernel Testing and Coverage" 1892 1893source "lib/kunit/Kconfig" 1894 1895config NOTIFIER_ERROR_INJECTION 1896 tristate "Notifier error injection" 1897 depends on DEBUG_KERNEL 1898 select DEBUG_FS 1899 help 1900 This option provides the ability to inject artificial errors to 1901 specified notifier chain callbacks. It is useful to test the error 1902 handling of notifier call chain failures. 1903 1904 Say N if unsure. 1905 1906config PM_NOTIFIER_ERROR_INJECT 1907 tristate "PM notifier error injection module" 1908 depends on PM && NOTIFIER_ERROR_INJECTION 1909 default m if PM_DEBUG 1910 help 1911 This option provides the ability to inject artificial errors to 1912 PM notifier chain callbacks. It is controlled through debugfs 1913 interface /sys/kernel/debug/notifier-error-inject/pm 1914 1915 If the notifier call chain should be failed with some events 1916 notified, write the error code to "actions/<notifier event>/error". 1917 1918 Example: Inject PM suspend error (-12 = -ENOMEM) 1919 1920 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1921 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1922 # echo mem > /sys/power/state 1923 bash: echo: write error: Cannot allocate memory 1924 1925 To compile this code as a module, choose M here: the module will 1926 be called pm-notifier-error-inject. 1927 1928 If unsure, say N. 1929 1930config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1931 tristate "OF reconfig notifier error injection module" 1932 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1933 help 1934 This option provides the ability to inject artificial errors to 1935 OF reconfig notifier chain callbacks. It is controlled 1936 through debugfs interface under 1937 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1938 1939 If the notifier call chain should be failed with some events 1940 notified, write the error code to "actions/<notifier event>/error". 1941 1942 To compile this code as a module, choose M here: the module will 1943 be called of-reconfig-notifier-error-inject. 1944 1945 If unsure, say N. 1946 1947config NETDEV_NOTIFIER_ERROR_INJECT 1948 tristate "Netdev notifier error injection module" 1949 depends on NET && NOTIFIER_ERROR_INJECTION 1950 help 1951 This option provides the ability to inject artificial errors to 1952 netdevice notifier chain callbacks. It is controlled through debugfs 1953 interface /sys/kernel/debug/notifier-error-inject/netdev 1954 1955 If the notifier call chain should be failed with some events 1956 notified, write the error code to "actions/<notifier event>/error". 1957 1958 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1959 1960 # cd /sys/kernel/debug/notifier-error-inject/netdev 1961 # echo -22 > actions/NETDEV_CHANGEMTU/error 1962 # ip link set eth0 mtu 1024 1963 RTNETLINK answers: Invalid argument 1964 1965 To compile this code as a module, choose M here: the module will 1966 be called netdev-notifier-error-inject. 1967 1968 If unsure, say N. 1969 1970config FUNCTION_ERROR_INJECTION 1971 bool "Fault-injections of functions" 1972 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1973 help 1974 Add fault injections into various functions that are annotated with 1975 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1976 value of these functions. This is useful to test error paths of code. 1977 1978 If unsure, say N 1979 1980config FAULT_INJECTION 1981 bool "Fault-injection framework" 1982 depends on DEBUG_KERNEL 1983 help 1984 Provide fault-injection framework. 1985 For more details, see Documentation/fault-injection/. 1986 1987config FAILSLAB 1988 bool "Fault-injection capability for kmalloc" 1989 depends on FAULT_INJECTION 1990 depends on SLAB || SLUB 1991 help 1992 Provide fault-injection capability for kmalloc. 1993 1994config FAIL_PAGE_ALLOC 1995 bool "Fault-injection capability for alloc_pages()" 1996 depends on FAULT_INJECTION 1997 help 1998 Provide fault-injection capability for alloc_pages(). 1999 2000config FAULT_INJECTION_USERCOPY 2001 bool "Fault injection capability for usercopy functions" 2002 depends on FAULT_INJECTION 2003 help 2004 Provides fault-injection capability to inject failures 2005 in usercopy functions (copy_from_user(), get_user(), ...). 2006 2007config FAIL_MAKE_REQUEST 2008 bool "Fault-injection capability for disk IO" 2009 depends on FAULT_INJECTION && BLOCK 2010 help 2011 Provide fault-injection capability for disk IO. 2012 2013config FAIL_IO_TIMEOUT 2014 bool "Fault-injection capability for faking disk interrupts" 2015 depends on FAULT_INJECTION && BLOCK 2016 help 2017 Provide fault-injection capability on end IO handling. This 2018 will make the block layer "forget" an interrupt as configured, 2019 thus exercising the error handling. 2020 2021 Only works with drivers that use the generic timeout handling, 2022 for others it won't do anything. 2023 2024config FAIL_FUTEX 2025 bool "Fault-injection capability for futexes" 2026 select DEBUG_FS 2027 depends on FAULT_INJECTION && FUTEX 2028 help 2029 Provide fault-injection capability for futexes. 2030 2031config FAULT_INJECTION_DEBUG_FS 2032 bool "Debugfs entries for fault-injection capabilities" 2033 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 2034 help 2035 Enable configuration of fault-injection capabilities via debugfs. 2036 2037config FAIL_FUNCTION 2038 bool "Fault-injection capability for functions" 2039 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 2040 help 2041 Provide function-based fault-injection capability. 2042 This will allow you to override a specific function with a return 2043 with given return value. As a result, function caller will see 2044 an error value and have to handle it. This is useful to test the 2045 error handling in various subsystems. 2046 2047config FAIL_MMC_REQUEST 2048 bool "Fault-injection capability for MMC IO" 2049 depends on FAULT_INJECTION_DEBUG_FS && MMC 2050 help 2051 Provide fault-injection capability for MMC IO. 2052 This will make the mmc core return data errors. This is 2053 useful to test the error handling in the mmc block device 2054 and to test how the mmc host driver handles retries from 2055 the block device. 2056 2057config FAIL_SUNRPC 2058 bool "Fault-injection capability for SunRPC" 2059 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2060 help 2061 Provide fault-injection capability for SunRPC and 2062 its consumers. 2063 2064config FAULT_INJECTION_CONFIGFS 2065 bool "Configfs interface for fault-injection capabilities" 2066 depends on FAULT_INJECTION 2067 select CONFIGFS_FS 2068 help 2069 This option allows configfs-based drivers to dynamically configure 2070 fault-injection via configfs. Each parameter for driver-specific 2071 fault-injection can be made visible as a configfs attribute in a 2072 configfs group. 2073 2074 2075config FAULT_INJECTION_STACKTRACE_FILTER 2076 bool "stacktrace filter for fault-injection capabilities" 2077 depends on FAULT_INJECTION 2078 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT 2079 select STACKTRACE 2080 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2081 help 2082 Provide stacktrace filter for fault-injection capabilities 2083 2084config ARCH_HAS_KCOV 2085 bool 2086 help 2087 An architecture should select this when it can successfully 2088 build and run with CONFIG_KCOV. This typically requires 2089 disabling instrumentation for some early boot code. 2090 2091config CC_HAS_SANCOV_TRACE_PC 2092 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2093 2094 2095config KCOV 2096 bool "Code coverage for fuzzing" 2097 depends on ARCH_HAS_KCOV 2098 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2099 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2100 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2101 select DEBUG_FS 2102 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2103 select OBJTOOL if HAVE_NOINSTR_HACK 2104 help 2105 KCOV exposes kernel code coverage information in a form suitable 2106 for coverage-guided fuzzing (randomized testing). 2107 2108 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2109 different machines and across reboots. If you need stable PC values, 2110 disable RANDOMIZE_BASE. 2111 2112 For more details, see Documentation/dev-tools/kcov.rst. 2113 2114config KCOV_ENABLE_COMPARISONS 2115 bool "Enable comparison operands collection by KCOV" 2116 depends on KCOV 2117 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2118 help 2119 KCOV also exposes operands of every comparison in the instrumented 2120 code along with operand sizes and PCs of the comparison instructions. 2121 These operands can be used by fuzzing engines to improve the quality 2122 of fuzzing coverage. 2123 2124config KCOV_INSTRUMENT_ALL 2125 bool "Instrument all code by default" 2126 depends on KCOV 2127 default y 2128 help 2129 If you are doing generic system call fuzzing (like e.g. syzkaller), 2130 then you will want to instrument the whole kernel and you should 2131 say y here. If you are doing more targeted fuzzing (like e.g. 2132 filesystem fuzzing with AFL) then you will want to enable coverage 2133 for more specific subsets of files, and should say n here. 2134 2135config KCOV_IRQ_AREA_SIZE 2136 hex "Size of interrupt coverage collection area in words" 2137 depends on KCOV 2138 default 0x40000 2139 help 2140 KCOV uses preallocated per-cpu areas to collect coverage from 2141 soft interrupts. This specifies the size of those areas in the 2142 number of unsigned long words. 2143 2144menuconfig RUNTIME_TESTING_MENU 2145 bool "Runtime Testing" 2146 def_bool y 2147 2148if RUNTIME_TESTING_MENU 2149 2150config TEST_DHRY 2151 tristate "Dhrystone benchmark test" 2152 help 2153 Enable this to include the Dhrystone 2.1 benchmark. This test 2154 calculates the number of Dhrystones per second, and the number of 2155 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided 2156 by 1757 (the number of Dhrystones per second obtained on the VAX 2157 11/780, nominally a 1 MIPS machine). 2158 2159 To run the benchmark, it needs to be enabled explicitly, either from 2160 the kernel command line (when built-in), or from userspace (when 2161 built-in or modular. 2162 2163 Run once during kernel boot: 2164 2165 test_dhry.run 2166 2167 Set number of iterations from kernel command line: 2168 2169 test_dhry.iterations=<n> 2170 2171 Set number of iterations from userspace: 2172 2173 echo <n> > /sys/module/test_dhry/parameters/iterations 2174 2175 Trigger manual run from userspace: 2176 2177 echo y > /sys/module/test_dhry/parameters/run 2178 2179 If the number of iterations is <= 0, the test will devise a suitable 2180 number of iterations (test runs for at least 2s) automatically. 2181 This process takes ca. 4s. 2182 2183 If unsure, say N. 2184 2185config LKDTM 2186 tristate "Linux Kernel Dump Test Tool Module" 2187 depends on DEBUG_FS 2188 help 2189 This module enables testing of the different dumping mechanisms by 2190 inducing system failures at predefined crash points. 2191 If you don't need it: say N 2192 Choose M here to compile this code as a module. The module will be 2193 called lkdtm. 2194 2195 Documentation on how to use the module can be found in 2196 Documentation/fault-injection/provoke-crashes.rst 2197 2198config CPUMASK_KUNIT_TEST 2199 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2200 depends on KUNIT 2201 default KUNIT_ALL_TESTS 2202 help 2203 Enable to turn on cpumask tests, running at boot or module load time. 2204 2205 For more information on KUnit and unit tests in general, please refer 2206 to the KUnit documentation in Documentation/dev-tools/kunit/. 2207 2208 If unsure, say N. 2209 2210config TEST_LIST_SORT 2211 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2212 depends on KUNIT 2213 default KUNIT_ALL_TESTS 2214 help 2215 Enable this to turn on 'list_sort()' function test. This test is 2216 executed only once during system boot (so affects only boot time), 2217 or at module load time. 2218 2219 If unsure, say N. 2220 2221config TEST_MIN_HEAP 2222 tristate "Min heap test" 2223 depends on DEBUG_KERNEL || m 2224 help 2225 Enable this to turn on min heap function tests. This test is 2226 executed only once during system boot (so affects only boot time), 2227 or at module load time. 2228 2229 If unsure, say N. 2230 2231config TEST_SORT 2232 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2233 depends on KUNIT 2234 default KUNIT_ALL_TESTS 2235 help 2236 This option enables the self-test function of 'sort()' at boot, 2237 or at module load time. 2238 2239 If unsure, say N. 2240 2241config TEST_DIV64 2242 tristate "64bit/32bit division and modulo test" 2243 depends on DEBUG_KERNEL || m 2244 help 2245 Enable this to turn on 'do_div()' function test. This test is 2246 executed only once during system boot (so affects only boot time), 2247 or at module load time. 2248 2249 If unsure, say N. 2250 2251config TEST_IOV_ITER 2252 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS 2253 depends on KUNIT 2254 default KUNIT_ALL_TESTS 2255 help 2256 Enable this to turn on testing of the operation of the I/O iterator 2257 (iov_iter). This test is executed only once during system boot (so 2258 affects only boot time), or at module load time. 2259 2260 If unsure, say N. 2261 2262config KPROBES_SANITY_TEST 2263 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2264 depends on DEBUG_KERNEL 2265 depends on KPROBES 2266 depends on KUNIT 2267 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2268 default KUNIT_ALL_TESTS 2269 help 2270 This option provides for testing basic kprobes functionality on 2271 boot. Samples of kprobe and kretprobe are inserted and 2272 verified for functionality. 2273 2274 Say N if you are unsure. 2275 2276config FPROBE_SANITY_TEST 2277 bool "Self test for fprobe" 2278 depends on DEBUG_KERNEL 2279 depends on FPROBE 2280 depends on KUNIT=y 2281 help 2282 This option will enable testing the fprobe when the system boot. 2283 A series of tests are made to verify that the fprobe is functioning 2284 properly. 2285 2286 Say N if you are unsure. 2287 2288config BACKTRACE_SELF_TEST 2289 tristate "Self test for the backtrace code" 2290 depends on DEBUG_KERNEL 2291 help 2292 This option provides a kernel module that can be used to test 2293 the kernel stack backtrace code. This option is not useful 2294 for distributions or general kernels, but only for kernel 2295 developers working on architecture code. 2296 2297 Note that if you want to also test saved backtraces, you will 2298 have to enable STACKTRACE as well. 2299 2300 Say N if you are unsure. 2301 2302config TEST_REF_TRACKER 2303 tristate "Self test for reference tracker" 2304 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2305 select REF_TRACKER 2306 help 2307 This option provides a kernel module performing tests 2308 using reference tracker infrastructure. 2309 2310 Say N if you are unsure. 2311 2312config RBTREE_TEST 2313 tristate "Red-Black tree test" 2314 depends on DEBUG_KERNEL 2315 help 2316 A benchmark measuring the performance of the rbtree library. 2317 Also includes rbtree invariant checks. 2318 2319config REED_SOLOMON_TEST 2320 tristate "Reed-Solomon library test" 2321 depends on DEBUG_KERNEL || m 2322 select REED_SOLOMON 2323 select REED_SOLOMON_ENC16 2324 select REED_SOLOMON_DEC16 2325 help 2326 This option enables the self-test function of rslib at boot, 2327 or at module load time. 2328 2329 If unsure, say N. 2330 2331config INTERVAL_TREE_TEST 2332 tristate "Interval tree test" 2333 depends on DEBUG_KERNEL 2334 select INTERVAL_TREE 2335 help 2336 A benchmark measuring the performance of the interval tree library 2337 2338config PERCPU_TEST 2339 tristate "Per cpu operations test" 2340 depends on m && DEBUG_KERNEL 2341 help 2342 Enable this option to build test module which validates per-cpu 2343 operations. 2344 2345 If unsure, say N. 2346 2347config ATOMIC64_SELFTEST 2348 tristate "Perform an atomic64_t self-test" 2349 help 2350 Enable this option to test the atomic64_t functions at boot or 2351 at module load time. 2352 2353 If unsure, say N. 2354 2355config ASYNC_RAID6_TEST 2356 tristate "Self test for hardware accelerated raid6 recovery" 2357 depends on ASYNC_RAID6_RECOV 2358 select ASYNC_MEMCPY 2359 help 2360 This is a one-shot self test that permutes through the 2361 recovery of all the possible two disk failure scenarios for a 2362 N-disk array. Recovery is performed with the asynchronous 2363 raid6 recovery routines, and will optionally use an offload 2364 engine if one is available. 2365 2366 If unsure, say N. 2367 2368config TEST_HEXDUMP 2369 tristate "Test functions located in the hexdump module at runtime" 2370 2371config STRING_SELFTEST 2372 tristate "Test string functions at runtime" 2373 2374config TEST_STRING_HELPERS 2375 tristate "Test functions located in the string_helpers module at runtime" 2376 2377config TEST_KSTRTOX 2378 tristate "Test kstrto*() family of functions at runtime" 2379 2380config TEST_PRINTF 2381 tristate "Test printf() family of functions at runtime" 2382 2383config TEST_SCANF 2384 tristate "Test scanf() family of functions at runtime" 2385 2386config TEST_BITMAP 2387 tristate "Test bitmap_*() family of functions at runtime" 2388 help 2389 Enable this option to test the bitmap functions at boot. 2390 2391 If unsure, say N. 2392 2393config TEST_UUID 2394 tristate "Test functions located in the uuid module at runtime" 2395 2396config TEST_XARRAY 2397 tristate "Test the XArray code at runtime" 2398 2399config TEST_MAPLE_TREE 2400 tristate "Test the Maple Tree code at runtime or module load" 2401 help 2402 Enable this option to test the maple tree code functions at boot, or 2403 when the module is loaded. Enable "Debug Maple Trees" will enable 2404 more verbose output on failures. 2405 2406 If unsure, say N. 2407 2408config TEST_RHASHTABLE 2409 tristate "Perform selftest on resizable hash table" 2410 help 2411 Enable this option to test the rhashtable functions at boot. 2412 2413 If unsure, say N. 2414 2415config TEST_IDA 2416 tristate "Perform selftest on IDA functions" 2417 2418config TEST_PARMAN 2419 tristate "Perform selftest on priority array manager" 2420 depends on PARMAN 2421 help 2422 Enable this option to test priority array manager on boot 2423 (or module load). 2424 2425 If unsure, say N. 2426 2427config TEST_IRQ_TIMINGS 2428 bool "IRQ timings selftest" 2429 depends on IRQ_TIMINGS 2430 help 2431 Enable this option to test the irq timings code on boot. 2432 2433 If unsure, say N. 2434 2435config TEST_LKM 2436 tristate "Test module loading with 'hello world' module" 2437 depends on m 2438 help 2439 This builds the "test_module" module that emits "Hello, world" 2440 on printk when loaded. It is designed to be used for basic 2441 evaluation of the module loading subsystem (for example when 2442 validating module verification). It lacks any extra dependencies, 2443 and will not normally be loaded by the system unless explicitly 2444 requested by name. 2445 2446 If unsure, say N. 2447 2448config TEST_BITOPS 2449 tristate "Test module for compilation of bitops operations" 2450 depends on m 2451 help 2452 This builds the "test_bitops" module that is much like the 2453 TEST_LKM module except that it does a basic exercise of the 2454 set/clear_bit macros and get_count_order/long to make sure there are 2455 no compiler warnings from C=1 sparse checker or -Wextra 2456 compilations. It has no dependencies and doesn't run or load unless 2457 explicitly requested by name. for example: modprobe test_bitops. 2458 2459 If unsure, say N. 2460 2461config TEST_VMALLOC 2462 tristate "Test module for stress/performance analysis of vmalloc allocator" 2463 default n 2464 depends on MMU 2465 depends on m 2466 help 2467 This builds the "test_vmalloc" module that should be used for 2468 stress and performance analysis. So, any new change for vmalloc 2469 subsystem can be evaluated from performance and stability point 2470 of view. 2471 2472 If unsure, say N. 2473 2474config TEST_USER_COPY 2475 tristate "Test user/kernel boundary protections" 2476 depends on m 2477 help 2478 This builds the "test_user_copy" module that runs sanity checks 2479 on the copy_to/from_user infrastructure, making sure basic 2480 user/kernel boundary testing is working. If it fails to load, 2481 a regression has been detected in the user/kernel memory boundary 2482 protections. 2483 2484 If unsure, say N. 2485 2486config TEST_BPF 2487 tristate "Test BPF filter functionality" 2488 depends on m && NET 2489 help 2490 This builds the "test_bpf" module that runs various test vectors 2491 against the BPF interpreter or BPF JIT compiler depending on the 2492 current setting. This is in particular useful for BPF JIT compiler 2493 development, but also to run regression tests against changes in 2494 the interpreter code. It also enables test stubs for eBPF maps and 2495 verifier used by user space verifier testsuite. 2496 2497 If unsure, say N. 2498 2499config TEST_BLACKHOLE_DEV 2500 tristate "Test blackhole netdev functionality" 2501 depends on m && NET 2502 help 2503 This builds the "test_blackhole_dev" module that validates the 2504 data path through this blackhole netdev. 2505 2506 If unsure, say N. 2507 2508config FIND_BIT_BENCHMARK 2509 tristate "Test find_bit functions" 2510 help 2511 This builds the "test_find_bit" module that measure find_*_bit() 2512 functions performance. 2513 2514 If unsure, say N. 2515 2516config TEST_FIRMWARE 2517 tristate "Test firmware loading via userspace interface" 2518 depends on FW_LOADER 2519 help 2520 This builds the "test_firmware" module that creates a userspace 2521 interface for testing firmware loading. This can be used to 2522 control the triggering of firmware loading without needing an 2523 actual firmware-using device. The contents can be rechecked by 2524 userspace. 2525 2526 If unsure, say N. 2527 2528config TEST_SYSCTL 2529 tristate "sysctl test driver" 2530 depends on PROC_SYSCTL 2531 help 2532 This builds the "test_sysctl" module. This driver enables to test the 2533 proc sysctl interfaces available to drivers safely without affecting 2534 production knobs which might alter system functionality. 2535 2536 If unsure, say N. 2537 2538config BITFIELD_KUNIT 2539 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2540 depends on KUNIT 2541 default KUNIT_ALL_TESTS 2542 help 2543 Enable this option to test the bitfield functions at boot. 2544 2545 KUnit tests run during boot and output the results to the debug log 2546 in TAP format (http://testanything.org/). Only useful for kernel devs 2547 running the KUnit test harness, and not intended for inclusion into a 2548 production build. 2549 2550 For more information on KUnit and unit tests in general please refer 2551 to the KUnit documentation in Documentation/dev-tools/kunit/. 2552 2553 If unsure, say N. 2554 2555config CHECKSUM_KUNIT 2556 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS 2557 depends on KUNIT 2558 default KUNIT_ALL_TESTS 2559 help 2560 Enable this option to test the checksum functions at boot. 2561 2562 KUnit tests run during boot and output the results to the debug log 2563 in TAP format (http://testanything.org/). Only useful for kernel devs 2564 running the KUnit test harness, and not intended for inclusion into a 2565 production build. 2566 2567 For more information on KUnit and unit tests in general please refer 2568 to the KUnit documentation in Documentation/dev-tools/kunit/. 2569 2570 If unsure, say N. 2571 2572config HASH_KUNIT_TEST 2573 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2574 depends on KUNIT 2575 default KUNIT_ALL_TESTS 2576 help 2577 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2578 integer (<linux/hash.h>) hash functions on boot. 2579 2580 KUnit tests run during boot and output the results to the debug log 2581 in TAP format (https://testanything.org/). Only useful for kernel devs 2582 running the KUnit test harness, and not intended for inclusion into a 2583 production build. 2584 2585 For more information on KUnit and unit tests in general please refer 2586 to the KUnit documentation in Documentation/dev-tools/kunit/. 2587 2588 This is intended to help people writing architecture-specific 2589 optimized versions. If unsure, say N. 2590 2591config RESOURCE_KUNIT_TEST 2592 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2593 depends on KUNIT 2594 default KUNIT_ALL_TESTS 2595 help 2596 This builds the resource API unit test. 2597 Tests the logic of API provided by resource.c and ioport.h. 2598 For more information on KUnit and unit tests in general please refer 2599 to the KUnit documentation in Documentation/dev-tools/kunit/. 2600 2601 If unsure, say N. 2602 2603config SYSCTL_KUNIT_TEST 2604 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2605 depends on KUNIT 2606 default KUNIT_ALL_TESTS 2607 help 2608 This builds the proc sysctl unit test, which runs on boot. 2609 Tests the API contract and implementation correctness of sysctl. 2610 For more information on KUnit and unit tests in general please refer 2611 to the KUnit documentation in Documentation/dev-tools/kunit/. 2612 2613 If unsure, say N. 2614 2615config LIST_KUNIT_TEST 2616 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2617 depends on KUNIT 2618 default KUNIT_ALL_TESTS 2619 help 2620 This builds the linked list KUnit test suite. 2621 It tests that the API and basic functionality of the list_head type 2622 and associated macros. 2623 2624 KUnit tests run during boot and output the results to the debug log 2625 in TAP format (https://testanything.org/). Only useful for kernel devs 2626 running the KUnit test harness, and not intended for inclusion into a 2627 production build. 2628 2629 For more information on KUnit and unit tests in general please refer 2630 to the KUnit documentation in Documentation/dev-tools/kunit/. 2631 2632 If unsure, say N. 2633 2634config HASHTABLE_KUNIT_TEST 2635 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS 2636 depends on KUNIT 2637 default KUNIT_ALL_TESTS 2638 help 2639 This builds the hashtable KUnit test suite. 2640 It tests the basic functionality of the API defined in 2641 include/linux/hashtable.h. For more information on KUnit and 2642 unit tests in general please refer to the KUnit documentation 2643 in Documentation/dev-tools/kunit/. 2644 2645 If unsure, say N. 2646 2647config LINEAR_RANGES_TEST 2648 tristate "KUnit test for linear_ranges" 2649 depends on KUNIT 2650 select LINEAR_RANGES 2651 help 2652 This builds the linear_ranges unit test, which runs on boot. 2653 Tests the linear_ranges logic correctness. 2654 For more information on KUnit and unit tests in general please refer 2655 to the KUnit documentation in Documentation/dev-tools/kunit/. 2656 2657 If unsure, say N. 2658 2659config CMDLINE_KUNIT_TEST 2660 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2661 depends on KUNIT 2662 default KUNIT_ALL_TESTS 2663 help 2664 This builds the cmdline API unit test. 2665 Tests the logic of API provided by cmdline.c. 2666 For more information on KUnit and unit tests in general please refer 2667 to the KUnit documentation in Documentation/dev-tools/kunit/. 2668 2669 If unsure, say N. 2670 2671config BITS_TEST 2672 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2673 depends on KUNIT 2674 default KUNIT_ALL_TESTS 2675 help 2676 This builds the bits unit test. 2677 Tests the logic of macros defined in bits.h. 2678 For more information on KUnit and unit tests in general please refer 2679 to the KUnit documentation in Documentation/dev-tools/kunit/. 2680 2681 If unsure, say N. 2682 2683config SLUB_KUNIT_TEST 2684 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2685 depends on SLUB_DEBUG && KUNIT 2686 default KUNIT_ALL_TESTS 2687 help 2688 This builds SLUB allocator unit test. 2689 Tests SLUB cache debugging functionality. 2690 For more information on KUnit and unit tests in general please refer 2691 to the KUnit documentation in Documentation/dev-tools/kunit/. 2692 2693 If unsure, say N. 2694 2695config RATIONAL_KUNIT_TEST 2696 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2697 depends on KUNIT && RATIONAL 2698 default KUNIT_ALL_TESTS 2699 help 2700 This builds the rational math unit test. 2701 For more information on KUnit and unit tests in general please refer 2702 to the KUnit documentation in Documentation/dev-tools/kunit/. 2703 2704 If unsure, say N. 2705 2706config MEMCPY_KUNIT_TEST 2707 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2708 depends on KUNIT 2709 default KUNIT_ALL_TESTS 2710 help 2711 Builds unit tests for memcpy(), memmove(), and memset() functions. 2712 For more information on KUnit and unit tests in general please refer 2713 to the KUnit documentation in Documentation/dev-tools/kunit/. 2714 2715 If unsure, say N. 2716 2717config MEMCPY_SLOW_KUNIT_TEST 2718 bool "Include exhaustive memcpy tests" 2719 depends on MEMCPY_KUNIT_TEST 2720 default y 2721 help 2722 Some memcpy tests are quite exhaustive in checking for overlaps 2723 and bit ranges. These can be very slow, so they are split out 2724 as a separate config, in case they need to be disabled. 2725 2726 Note this config option will be replaced by the use of KUnit test 2727 attributes. 2728 2729config IS_SIGNED_TYPE_KUNIT_TEST 2730 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2731 depends on KUNIT 2732 default KUNIT_ALL_TESTS 2733 help 2734 Builds unit tests for the is_signed_type() macro. 2735 2736 For more information on KUnit and unit tests in general please refer 2737 to the KUnit documentation in Documentation/dev-tools/kunit/. 2738 2739 If unsure, say N. 2740 2741config OVERFLOW_KUNIT_TEST 2742 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2743 depends on KUNIT 2744 default KUNIT_ALL_TESTS 2745 help 2746 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2747 related functions. 2748 2749 For more information on KUnit and unit tests in general please refer 2750 to the KUnit documentation in Documentation/dev-tools/kunit/. 2751 2752 If unsure, say N. 2753 2754config STACKINIT_KUNIT_TEST 2755 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2756 depends on KUNIT 2757 default KUNIT_ALL_TESTS 2758 help 2759 Test if the kernel is zero-initializing stack variables and 2760 padding. Coverage is controlled by compiler flags, 2761 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2762 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2763 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2764 2765config FORTIFY_KUNIT_TEST 2766 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2767 depends on KUNIT && FORTIFY_SOURCE 2768 default KUNIT_ALL_TESTS 2769 help 2770 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2771 by the str*() and mem*() family of functions. For testing runtime 2772 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2773 2774config HW_BREAKPOINT_KUNIT_TEST 2775 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2776 depends on HAVE_HW_BREAKPOINT 2777 depends on KUNIT=y 2778 default KUNIT_ALL_TESTS 2779 help 2780 Tests for hw_breakpoint constraints accounting. 2781 2782 If unsure, say N. 2783 2784config STRCAT_KUNIT_TEST 2785 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS 2786 depends on KUNIT 2787 default KUNIT_ALL_TESTS 2788 2789config STRSCPY_KUNIT_TEST 2790 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2791 depends on KUNIT 2792 default KUNIT_ALL_TESTS 2793 2794config SIPHASH_KUNIT_TEST 2795 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2796 depends on KUNIT 2797 default KUNIT_ALL_TESTS 2798 help 2799 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2800 functions on boot (or module load). 2801 2802 This is intended to help people writing architecture-specific 2803 optimized versions. If unsure, say N. 2804 2805config TEST_UDELAY 2806 tristate "udelay test driver" 2807 help 2808 This builds the "udelay_test" module that helps to make sure 2809 that udelay() is working properly. 2810 2811 If unsure, say N. 2812 2813config TEST_STATIC_KEYS 2814 tristate "Test static keys" 2815 depends on m 2816 help 2817 Test the static key interfaces. 2818 2819 If unsure, say N. 2820 2821config TEST_DYNAMIC_DEBUG 2822 tristate "Test DYNAMIC_DEBUG" 2823 depends on DYNAMIC_DEBUG 2824 help 2825 This module registers a tracer callback to count enabled 2826 pr_debugs in a 'do_debugging' function, then alters their 2827 enablements, calls the function, and compares counts. 2828 2829 If unsure, say N. 2830 2831config TEST_KMOD 2832 tristate "kmod stress tester" 2833 depends on m 2834 depends on NETDEVICES && NET_CORE && INET # for TUN 2835 depends on BLOCK 2836 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2837 select TEST_LKM 2838 select XFS_FS 2839 select TUN 2840 select BTRFS_FS 2841 help 2842 Test the kernel's module loading mechanism: kmod. kmod implements 2843 support to load modules using the Linux kernel's usermode helper. 2844 This test provides a series of tests against kmod. 2845 2846 Although technically you can either build test_kmod as a module or 2847 into the kernel we disallow building it into the kernel since 2848 it stress tests request_module() and this will very likely cause 2849 some issues by taking over precious threads available from other 2850 module load requests, ultimately this could be fatal. 2851 2852 To run tests run: 2853 2854 tools/testing/selftests/kmod/kmod.sh --help 2855 2856 If unsure, say N. 2857 2858config TEST_DEBUG_VIRTUAL 2859 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2860 depends on DEBUG_VIRTUAL 2861 help 2862 Test the kernel's ability to detect incorrect calls to 2863 virt_to_phys() done against the non-linear part of the 2864 kernel's virtual address map. 2865 2866 If unsure, say N. 2867 2868config TEST_MEMCAT_P 2869 tristate "Test memcat_p() helper function" 2870 help 2871 Test the memcat_p() helper for correctly merging two 2872 pointer arrays together. 2873 2874 If unsure, say N. 2875 2876config TEST_LIVEPATCH 2877 tristate "Test livepatching" 2878 default n 2879 depends on DYNAMIC_DEBUG 2880 depends on LIVEPATCH 2881 depends on m 2882 help 2883 Test kernel livepatching features for correctness. The tests will 2884 load test modules that will be livepatched in various scenarios. 2885 2886 To run all the livepatching tests: 2887 2888 make -C tools/testing/selftests TARGETS=livepatch run_tests 2889 2890 Alternatively, individual tests may be invoked: 2891 2892 tools/testing/selftests/livepatch/test-callbacks.sh 2893 tools/testing/selftests/livepatch/test-livepatch.sh 2894 tools/testing/selftests/livepatch/test-shadow-vars.sh 2895 2896 If unsure, say N. 2897 2898config TEST_OBJAGG 2899 tristate "Perform selftest on object aggreration manager" 2900 default n 2901 depends on OBJAGG 2902 help 2903 Enable this option to test object aggregation manager on boot 2904 (or module load). 2905 2906config TEST_MEMINIT 2907 tristate "Test heap/page initialization" 2908 help 2909 Test if the kernel is zero-initializing heap and page allocations. 2910 This can be useful to test init_on_alloc and init_on_free features. 2911 2912 If unsure, say N. 2913 2914config TEST_HMM 2915 tristate "Test HMM (Heterogeneous Memory Management)" 2916 depends on TRANSPARENT_HUGEPAGE 2917 depends on DEVICE_PRIVATE 2918 select HMM_MIRROR 2919 select MMU_NOTIFIER 2920 help 2921 This is a pseudo device driver solely for testing HMM. 2922 Say M here if you want to build the HMM test module. 2923 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2924 2925 If unsure, say N. 2926 2927config TEST_FREE_PAGES 2928 tristate "Test freeing pages" 2929 help 2930 Test that a memory leak does not occur due to a race between 2931 freeing a block of pages and a speculative page reference. 2932 Loading this module is safe if your kernel has the bug fixed. 2933 If the bug is not fixed, it will leak gigabytes of memory and 2934 probably OOM your system. 2935 2936config TEST_FPU 2937 tristate "Test floating point operations in kernel space" 2938 depends on X86 && !KCOV_INSTRUMENT_ALL 2939 help 2940 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2941 which will trigger a sequence of floating point operations. This is used 2942 for self-testing floating point control register setting in 2943 kernel_fpu_begin(). 2944 2945 If unsure, say N. 2946 2947config TEST_CLOCKSOURCE_WATCHDOG 2948 tristate "Test clocksource watchdog in kernel space" 2949 depends on CLOCKSOURCE_WATCHDOG 2950 help 2951 Enable this option to create a kernel module that will trigger 2952 a test of the clocksource watchdog. This module may be loaded 2953 via modprobe or insmod in which case it will run upon being 2954 loaded, or it may be built in, in which case it will run 2955 shortly after boot. 2956 2957 If unsure, say N. 2958 2959config TEST_OBJPOOL 2960 tristate "Test module for correctness and stress of objpool" 2961 default n 2962 depends on m && DEBUG_KERNEL 2963 help 2964 This builds the "test_objpool" module that should be used for 2965 correctness verification and concurrent testings of objects 2966 allocation and reclamation. 2967 2968 If unsure, say N. 2969 2970endif # RUNTIME_TESTING_MENU 2971 2972config ARCH_USE_MEMTEST 2973 bool 2974 help 2975 An architecture should select this when it uses early_memtest() 2976 during boot process. 2977 2978config MEMTEST 2979 bool "Memtest" 2980 depends on ARCH_USE_MEMTEST 2981 help 2982 This option adds a kernel parameter 'memtest', which allows memtest 2983 to be set and executed. 2984 memtest=0, mean disabled; -- default 2985 memtest=1, mean do 1 test pattern; 2986 ... 2987 memtest=17, mean do 17 test patterns. 2988 If you are unsure how to answer this question, answer N. 2989 2990 2991 2992config HYPERV_TESTING 2993 bool "Microsoft Hyper-V driver testing" 2994 default n 2995 depends on HYPERV && DEBUG_FS 2996 help 2997 Select this option to enable Hyper-V vmbus testing. 2998 2999endmenu # "Kernel Testing and Coverage" 3000 3001menu "Rust hacking" 3002 3003config RUST_DEBUG_ASSERTIONS 3004 bool "Debug assertions" 3005 depends on RUST 3006 help 3007 Enables rustc's `-Cdebug-assertions` codegen option. 3008 3009 This flag lets you turn `cfg(debug_assertions)` conditional 3010 compilation on or off. This can be used to enable extra debugging 3011 code in development but not in production. For example, it controls 3012 the behavior of the standard library's `debug_assert!` macro. 3013 3014 Note that this will apply to all Rust code, including `core`. 3015 3016 If unsure, say N. 3017 3018config RUST_OVERFLOW_CHECKS 3019 bool "Overflow checks" 3020 default y 3021 depends on RUST 3022 help 3023 Enables rustc's `-Coverflow-checks` codegen option. 3024 3025 This flag allows you to control the behavior of runtime integer 3026 overflow. When overflow-checks are enabled, a Rust panic will occur 3027 on overflow. 3028 3029 Note that this will apply to all Rust code, including `core`. 3030 3031 If unsure, say Y. 3032 3033config RUST_BUILD_ASSERT_ALLOW 3034 bool "Allow unoptimized build-time assertions" 3035 depends on RUST 3036 help 3037 Controls how are `build_error!` and `build_assert!` handled during build. 3038 3039 If calls to them exist in the binary, it may indicate a violated invariant 3040 or that the optimizer failed to verify the invariant during compilation. 3041 3042 This should not happen, thus by default the build is aborted. However, 3043 as an escape hatch, you can choose Y here to ignore them during build 3044 and let the check be carried at runtime (with `panic!` being called if 3045 the check fails). 3046 3047 If unsure, say N. 3048 3049config RUST_KERNEL_DOCTESTS 3050 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS 3051 depends on RUST && KUNIT=y 3052 default KUNIT_ALL_TESTS 3053 help 3054 This builds the documentation tests of the `kernel` crate 3055 as KUnit tests. 3056 3057 For more information on KUnit and unit tests in general, 3058 please refer to the KUnit documentation in Documentation/dev-tools/kunit/. 3059 3060 If unsure, say N. 3061 3062endmenu # "Rust" 3063 3064endmenu # Kernel hacking 3065