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 is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which 235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 236config AS_HAS_NON_CONST_LEB128 237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) 238 239choice 240 prompt "Debug information" 241 depends on DEBUG_KERNEL 242 help 243 Selecting something other than "None" results in a kernel image 244 that will include debugging info resulting in a larger kernel image. 245 This adds debug symbols to the kernel and modules (gcc -g), and 246 is needed if you intend to use kernel crashdump or binary object 247 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 248 249 Choose which version of DWARF debug info to emit. If unsure, 250 select "Toolchain default". 251 252config DEBUG_INFO_NONE 253 bool "Disable debug information" 254 help 255 Do not build the kernel with debugging information, which will 256 result in a faster and smaller build. 257 258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 259 bool "Rely on the toolchain's implicit default DWARF version" 260 select DEBUG_INFO 261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) 262 help 263 The implicit default version of DWARF debug info produced by a 264 toolchain changes over time. 265 266 This can break consumers of the debug info that haven't upgraded to 267 support newer revisions, and prevent testing newer versions, but 268 those should be less common scenarios. 269 270config DEBUG_INFO_DWARF4 271 bool "Generate DWARF Version 4 debuginfo" 272 select DEBUG_INFO 273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502) 274 help 275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2 276 if using clang without clang's integrated assembler, and gdb 7.0+. 277 278 If you have consumers of DWARF debug info that are not ready for 279 newer revisions of DWARF, you may wish to choose this or have your 280 config select this. 281 282config DEBUG_INFO_DWARF5 283 bool "Generate DWARF Version 5 debuginfo" 284 select DEBUG_INFO 285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) 286 help 287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 289 draft features until 7.0), and gdb 8.0+. 290 291 Changes to the structure of debug info in Version 5 allow for around 292 15-18% savings in resulting image and debug info section sizes as 293 compared to DWARF Version 4. DWARF Version 5 standardizes previous 294 extensions such as accelerators for symbol indexing and the format 295 for fission (.dwo/.dwp) files. Users may not want to select this 296 config if they rely on tooling that has not yet been updated to 297 support DWARF Version 5. 298 299endchoice # "Debug information" 300 301if DEBUG_INFO 302 303config DEBUG_INFO_REDUCED 304 bool "Reduce debugging information" 305 help 306 If you say Y here gcc is instructed to generate less debugging 307 information for structure types. This means that tools that 308 need full debugging information (like kgdb or systemtap) won't 309 be happy. But if you merely need debugging information to 310 resolve line numbers there is no loss. Advantage is that 311 build directory object sizes shrink dramatically over a full 312 DEBUG_INFO build and compile times are reduced too. 313 Only works with newer gcc versions. 314 315choice 316 prompt "Compressed Debug information" 317 help 318 Compress the resulting debug info. Results in smaller debug info sections, 319 but requires that consumers are able to decompress the results. 320 321 If unsure, choose DEBUG_INFO_COMPRESSED_NONE. 322 323config DEBUG_INFO_COMPRESSED_NONE 324 bool "Don't compress debug information" 325 help 326 Don't compress debug info sections. 327 328config DEBUG_INFO_COMPRESSED_ZLIB 329 bool "Compress debugging information with zlib" 330 depends on $(cc-option,-gz=zlib) 331 depends on $(ld-option,--compress-debug-sections=zlib) 332 help 333 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 334 5.0+, binutils 2.26+, and zlib. 335 336 Users of dpkg-deb via scripts/package/builddeb may find an increase in 337 size of their debug .deb packages with this config set, due to the 338 debug info being compressed with zlib, then the object files being 339 recompressed with a different compression scheme. But this is still 340 preferable to setting $KDEB_COMPRESS to "none" which would be even 341 larger. 342 343config DEBUG_INFO_COMPRESSED_ZSTD 344 bool "Compress debugging information with zstd" 345 depends on $(cc-option,-gz=zstd) 346 depends on $(ld-option,--compress-debug-sections=zstd) 347 help 348 Compress the debug information using zstd. This may provide better 349 compression than zlib, for about the same time costs, but requires newer 350 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and 351 zstd. 352 353endchoice # "Compressed Debug information" 354 355config DEBUG_INFO_SPLIT 356 bool "Produce split debuginfo in .dwo files" 357 depends on $(cc-option,-gsplit-dwarf) 358 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC 359 # prior to 12.x: 360 # https://github.com/llvm/llvm-project/issues/56642 361 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 362 depends on !RISCV || GCC_VERSION >= 120000 363 help 364 Generate debug info into separate .dwo files. This significantly 365 reduces the build directory size for builds with DEBUG_INFO, 366 because it stores the information only once on disk in .dwo 367 files instead of multiple times in object files and executables. 368 In addition the debug information is also compressed. 369 370 Requires recent gcc (4.7+) and recent gdb/binutils. 371 Any tool that packages or reads debug information would need 372 to know about the .dwo files and include them. 373 Incompatible with older versions of ccache. 374 375config DEBUG_INFO_BTF 376 bool "Generate BTF typeinfo" 377 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 378 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 379 depends on BPF_SYSCALL 380 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 381 help 382 Generate deduplicated BTF type information from DWARF debug info. 383 Turning this on expects presence of pahole tool, which will convert 384 DWARF type info into equivalent deduplicated BTF type info. 385 386config PAHOLE_HAS_SPLIT_BTF 387 def_bool PAHOLE_VERSION >= 119 388 389config PAHOLE_HAS_BTF_TAG 390 def_bool PAHOLE_VERSION >= 123 391 depends on CC_IS_CLANG 392 help 393 Decide whether pahole emits btf_tag attributes (btf_type_tag and 394 btf_decl_tag) or not. Currently only clang compiler implements 395 these attributes, so make the config depend on CC_IS_CLANG. 396 397config PAHOLE_HAS_LANG_EXCLUDE 398 def_bool PAHOLE_VERSION >= 124 399 help 400 Support for the --lang_exclude flag which makes pahole exclude 401 compilation units from the supplied language. Used in Kbuild to 402 omit Rust CUs which are not supported in version 1.24 of pahole, 403 otherwise it would emit malformed kernel and module binaries when 404 using DEBUG_INFO_BTF_MODULES. 405 406config DEBUG_INFO_BTF_MODULES 407 def_bool y 408 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 409 help 410 Generate compact split BTF type information for kernel modules. 411 412config MODULE_ALLOW_BTF_MISMATCH 413 bool "Allow loading modules with non-matching BTF type info" 414 depends on DEBUG_INFO_BTF_MODULES 415 help 416 For modules whose split BTF does not match vmlinux, load without 417 BTF rather than refusing to load. The default behavior with 418 module BTF enabled is to reject modules with such mismatches; 419 this option will still load module BTF where possible but ignore 420 it when a mismatch is found. 421 422config GDB_SCRIPTS 423 bool "Provide GDB scripts for kernel debugging" 424 help 425 This creates the required links to GDB helper scripts in the 426 build directory. If you load vmlinux into gdb, the helper 427 scripts will be automatically imported by gdb as well, and 428 additional functions are available to analyze a Linux kernel 429 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 430 for further details. 431 432endif # DEBUG_INFO 433 434config FRAME_WARN 435 int "Warn for stack frames larger than" 436 range 0 8192 437 default 0 if KMSAN 438 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 439 default 2048 if PARISC 440 default 1536 if (!64BIT && XTENSA) 441 default 1280 if KASAN && !64BIT 442 default 1024 if !64BIT 443 default 2048 if 64BIT 444 help 445 Tell the compiler to warn at build time for stack frames larger than this. 446 Setting this too low will cause a lot of warnings. 447 Setting it to 0 disables the warning. 448 449config STRIP_ASM_SYMS 450 bool "Strip assembler-generated symbols during link" 451 default n 452 help 453 Strip internal assembler-generated symbols during a link (symbols 454 that look like '.Lxxx') so they don't pollute the output of 455 get_wchan() and suchlike. 456 457config READABLE_ASM 458 bool "Generate readable assembler code" 459 depends on DEBUG_KERNEL 460 depends on CC_IS_GCC 461 help 462 Disable some compiler optimizations that tend to generate human unreadable 463 assembler output. This may make the kernel slightly slower, but it helps 464 to keep kernel developers who have to stare a lot at assembler listings 465 sane. 466 467config HEADERS_INSTALL 468 bool "Install uapi headers to usr/include" 469 depends on !UML 470 help 471 This option will install uapi headers (headers exported to user-space) 472 into the usr/include directory for use during the kernel build. 473 This is unneeded for building the kernel itself, but needed for some 474 user-space program samples. It is also needed by some features such 475 as uapi header sanity checks. 476 477config DEBUG_SECTION_MISMATCH 478 bool "Enable full Section mismatch analysis" 479 depends on CC_IS_GCC 480 help 481 The section mismatch analysis checks if there are illegal 482 references from one section to another section. 483 During linktime or runtime, some sections are dropped; 484 any use of code/data previously in these sections would 485 most likely result in an oops. 486 In the code, functions and variables are annotated with 487 __init,, etc. (see the full list in include/linux/init.h), 488 which results in the code/data being placed in specific sections. 489 The section mismatch analysis is always performed after a full 490 kernel build, and enabling this option causes the following 491 additional step to occur: 492 - Add the option -fno-inline-functions-called-once to gcc commands. 493 When inlining a function annotated with __init in a non-init 494 function, we would lose the section information and thus 495 the analysis would not catch the illegal reference. 496 This option tells gcc to inline less (but it does result in 497 a larger kernel). 498 499config SECTION_MISMATCH_WARN_ONLY 500 bool "Make section mismatch errors non-fatal" 501 default y 502 help 503 If you say N here, the build process will fail if there are any 504 section mismatch, instead of just throwing warnings. 505 506 If unsure, say Y. 507 508config DEBUG_FORCE_FUNCTION_ALIGN_64B 509 bool "Force all function address 64B aligned" 510 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390) 511 select FUNCTION_ALIGNMENT_64B 512 help 513 There are cases that a commit from one domain changes the function 514 address alignment of other domains, and cause magic performance 515 bump (regression or improvement). Enable this option will help to 516 verify if the bump is caused by function alignment changes, while 517 it will slightly increase the kernel size and affect icache usage. 518 519 It is mainly for debug and performance tuning use. 520 521# 522# Select this config option from the architecture Kconfig, if it 523# is preferred to always offer frame pointers as a config 524# option on the architecture (regardless of KERNEL_DEBUG): 525# 526config ARCH_WANT_FRAME_POINTERS 527 bool 528 529config FRAME_POINTER 530 bool "Compile the kernel with frame pointers" 531 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 532 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 533 help 534 If you say Y here the resulting kernel image will be slightly 535 larger and slower, but it gives very useful debugging information 536 in case of kernel bugs. (precise oopses/stacktraces/warnings) 537 538config OBJTOOL 539 bool 540 541config STACK_VALIDATION 542 bool "Compile-time stack metadata validation" 543 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 544 select OBJTOOL 545 default n 546 help 547 Validate frame pointer rules at compile-time. This helps ensure that 548 runtime stack traces are more reliable. 549 550 For more information, see 551 tools/objtool/Documentation/objtool.txt. 552 553config NOINSTR_VALIDATION 554 bool 555 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 556 select OBJTOOL 557 default y 558 559config VMLINUX_MAP 560 bool "Generate vmlinux.map file when linking" 561 depends on EXPERT 562 help 563 Selecting this option will pass "-Map=vmlinux.map" to ld 564 when linking vmlinux. That file can be useful for verifying 565 and debugging magic section games, and for seeing which 566 pieces of code get eliminated with 567 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 568 569config DEBUG_FORCE_WEAK_PER_CPU 570 bool "Force weak per-cpu definitions" 571 depends on DEBUG_KERNEL 572 help 573 s390 and alpha require percpu variables in modules to be 574 defined weak to work around addressing range issue which 575 puts the following two restrictions on percpu variable 576 definitions. 577 578 1. percpu symbols must be unique whether static or not 579 2. percpu variables can't be defined inside a function 580 581 To ensure that generic code follows the above rules, this 582 option forces all percpu variables to be defined as weak. 583 584endmenu # "Compiler options" 585 586menu "Generic Kernel Debugging Instruments" 587 588config MAGIC_SYSRQ 589 bool "Magic SysRq key" 590 depends on !UML 591 help 592 If you say Y here, you will have some control over the system even 593 if the system crashes for example during kernel debugging (e.g., you 594 will be able to flush the buffer cache to disk, reboot the system 595 immediately or dump some status information). This is accomplished 596 by pressing various keys while holding SysRq (Alt+PrintScreen). It 597 also works on a serial console (on PC hardware at least), if you 598 send a BREAK and then within 5 seconds a command keypress. The 599 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 600 Don't say Y unless you really know what this hack does. 601 602config MAGIC_SYSRQ_DEFAULT_ENABLE 603 hex "Enable magic SysRq key functions by default" 604 depends on MAGIC_SYSRQ 605 default 0x1 606 help 607 Specifies which SysRq key functions are enabled by default. 608 This may be set to 1 or 0 to enable or disable them all, or 609 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 610 611config MAGIC_SYSRQ_SERIAL 612 bool "Enable magic SysRq key over serial" 613 depends on MAGIC_SYSRQ 614 default y 615 help 616 Many embedded boards have a disconnected TTL level serial which can 617 generate some garbage that can lead to spurious false sysrq detects. 618 This option allows you to decide whether you want to enable the 619 magic SysRq key. 620 621config MAGIC_SYSRQ_SERIAL_SEQUENCE 622 string "Char sequence that enables magic SysRq over serial" 623 depends on MAGIC_SYSRQ_SERIAL 624 default "" 625 help 626 Specifies a sequence of characters that can follow BREAK to enable 627 SysRq on a serial console. 628 629 If unsure, leave an empty string and the option will not be enabled. 630 631config DEBUG_FS 632 bool "Debug Filesystem" 633 help 634 debugfs is a virtual file system that kernel developers use to put 635 debugging files into. Enable this option to be able to read and 636 write to these files. 637 638 For detailed documentation on the debugfs API, see 639 Documentation/filesystems/. 640 641 If unsure, say N. 642 643choice 644 prompt "Debugfs default access" 645 depends on DEBUG_FS 646 default DEBUG_FS_ALLOW_ALL 647 help 648 This selects the default access restrictions for debugfs. 649 It can be overridden with kernel command line option 650 debugfs=[on,no-mount,off]. The restrictions apply for API access 651 and filesystem registration. 652 653config DEBUG_FS_ALLOW_ALL 654 bool "Access normal" 655 help 656 No restrictions apply. Both API and filesystem registration 657 is on. This is the normal default operation. 658 659config DEBUG_FS_DISALLOW_MOUNT 660 bool "Do not register debugfs as filesystem" 661 help 662 The API is open but filesystem is not loaded. Clients can still do 663 their work and read with debug tools that do not need 664 debugfs filesystem. 665 666config DEBUG_FS_ALLOW_NONE 667 bool "No access" 668 help 669 Access is off. Clients get -PERM when trying to create nodes in 670 debugfs tree and debugfs is not registered as a filesystem. 671 Client can then back-off or continue without debugfs access. 672 673endchoice 674 675source "lib/Kconfig.kgdb" 676source "lib/Kconfig.ubsan" 677source "lib/Kconfig.kcsan" 678 679endmenu 680 681menu "Networking Debugging" 682 683source "net/Kconfig.debug" 684 685endmenu # "Networking Debugging" 686 687menu "Memory Debugging" 688 689source "mm/Kconfig.debug" 690 691config DEBUG_OBJECTS 692 bool "Debug object operations" 693 depends on DEBUG_KERNEL 694 help 695 If you say Y here, additional code will be inserted into the 696 kernel to track the life time of various objects and validate 697 the operations on those objects. 698 699config DEBUG_OBJECTS_SELFTEST 700 bool "Debug objects selftest" 701 depends on DEBUG_OBJECTS 702 help 703 This enables the selftest of the object debug code. 704 705config DEBUG_OBJECTS_FREE 706 bool "Debug objects in freed memory" 707 depends on DEBUG_OBJECTS 708 help 709 This enables checks whether a k/v free operation frees an area 710 which contains an object which has not been deactivated 711 properly. This can make kmalloc/kfree-intensive workloads 712 much slower. 713 714config DEBUG_OBJECTS_TIMERS 715 bool "Debug timer objects" 716 depends on DEBUG_OBJECTS 717 help 718 If you say Y here, additional code will be inserted into the 719 timer routines to track the life time of timer objects and 720 validate the timer operations. 721 722config DEBUG_OBJECTS_WORK 723 bool "Debug work objects" 724 depends on DEBUG_OBJECTS 725 help 726 If you say Y here, additional code will be inserted into the 727 work queue routines to track the life time of work objects and 728 validate the work operations. 729 730config DEBUG_OBJECTS_RCU_HEAD 731 bool "Debug RCU callbacks objects" 732 depends on DEBUG_OBJECTS 733 help 734 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 735 736config DEBUG_OBJECTS_PERCPU_COUNTER 737 bool "Debug percpu counter objects" 738 depends on DEBUG_OBJECTS 739 help 740 If you say Y here, additional code will be inserted into the 741 percpu counter routines to track the life time of percpu counter 742 objects and validate the percpu counter operations. 743 744config DEBUG_OBJECTS_ENABLE_DEFAULT 745 int "debug_objects bootup default value (0-1)" 746 range 0 1 747 default "1" 748 depends on DEBUG_OBJECTS 749 help 750 Debug objects boot parameter default value 751 752config SHRINKER_DEBUG 753 bool "Enable shrinker debugging support" 754 depends on DEBUG_FS 755 help 756 Say Y to enable the shrinker debugfs interface which provides 757 visibility into the kernel memory shrinkers subsystem. 758 Disable it to avoid an extra memory footprint. 759 760config DEBUG_STACK_USAGE 761 bool "Stack utilization instrumentation" 762 depends on DEBUG_KERNEL && !IA64 763 help 764 Enables the display of the minimum amount of free stack which each 765 task has ever had available in the sysrq-T and sysrq-P debug output. 766 767 This option will slow down process creation somewhat. 768 769config SCHED_STACK_END_CHECK 770 bool "Detect stack corruption on calls to schedule()" 771 depends on DEBUG_KERNEL 772 default n 773 help 774 This option checks for a stack overrun on calls to schedule(). 775 If the stack end location is found to be over written always panic as 776 the content of the corrupted region can no longer be trusted. 777 This is to ensure no erroneous behaviour occurs which could result in 778 data corruption or a sporadic crash at a later stage once the region 779 is examined. The runtime overhead introduced is minimal. 780 781config ARCH_HAS_DEBUG_VM_PGTABLE 782 bool 783 help 784 An architecture should select this when it can successfully 785 build and run DEBUG_VM_PGTABLE. 786 787config DEBUG_VM_IRQSOFF 788 def_bool DEBUG_VM && !PREEMPT_RT 789 790config DEBUG_VM 791 bool "Debug VM" 792 depends on DEBUG_KERNEL 793 help 794 Enable this to turn on extended checks in the virtual-memory system 795 that may impact performance. 796 797 If unsure, say N. 798 799config DEBUG_VM_SHOOT_LAZIES 800 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation" 801 depends on DEBUG_VM 802 depends on MMU_LAZY_TLB_SHOOTDOWN 803 help 804 Enable additional IPIs that ensure lazy tlb mm references are removed 805 before the mm is freed. 806 807 If unsure, say N. 808 809config DEBUG_VM_MAPLE_TREE 810 bool "Debug VM maple trees" 811 depends on DEBUG_VM 812 select DEBUG_MAPLE_TREE 813 help 814 Enable VM maple tree debugging information and extra validations. 815 816 If unsure, say N. 817 818config DEBUG_VM_RB 819 bool "Debug VM red-black trees" 820 depends on DEBUG_VM 821 help 822 Enable VM red-black tree debugging information and extra validations. 823 824 If unsure, say N. 825 826config DEBUG_VM_PGFLAGS 827 bool "Debug page-flags operations" 828 depends on DEBUG_VM 829 help 830 Enables extra validation on page flags operations. 831 832 If unsure, say N. 833 834config DEBUG_VM_PGTABLE 835 bool "Debug arch page table for semantics compliance" 836 depends on MMU 837 depends on ARCH_HAS_DEBUG_VM_PGTABLE 838 default y if DEBUG_VM 839 help 840 This option provides a debug method which can be used to test 841 architecture page table helper functions on various platforms in 842 verifying if they comply with expected generic MM semantics. This 843 will help architecture code in making sure that any changes or 844 new additions of these helpers still conform to expected 845 semantics of the generic MM. Platforms will have to opt in for 846 this through ARCH_HAS_DEBUG_VM_PGTABLE. 847 848 If unsure, say N. 849 850config ARCH_HAS_DEBUG_VIRTUAL 851 bool 852 853config DEBUG_VIRTUAL 854 bool "Debug VM translations" 855 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 856 help 857 Enable some costly sanity checks in virtual to page code. This can 858 catch mistakes with virt_to_page() and friends. 859 860 If unsure, say N. 861 862config DEBUG_NOMMU_REGIONS 863 bool "Debug the global anon/private NOMMU mapping region tree" 864 depends on DEBUG_KERNEL && !MMU 865 help 866 This option causes the global tree of anonymous and private mapping 867 regions to be regularly checked for invalid topology. 868 869config DEBUG_MEMORY_INIT 870 bool "Debug memory initialisation" if EXPERT 871 default !EXPERT 872 help 873 Enable this for additional checks during memory initialisation. 874 The sanity checks verify aspects of the VM such as the memory model 875 and other information provided by the architecture. Verbose 876 information will be printed at KERN_DEBUG loglevel depending 877 on the mminit_loglevel= command-line option. 878 879 If unsure, say Y 880 881config MEMORY_NOTIFIER_ERROR_INJECT 882 tristate "Memory hotplug notifier error injection module" 883 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 884 help 885 This option provides the ability to inject artificial errors to 886 memory hotplug notifier chain callbacks. It is controlled through 887 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 888 889 If the notifier call chain should be failed with some events 890 notified, write the error code to "actions/<notifier event>/error". 891 892 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 893 894 # cd /sys/kernel/debug/notifier-error-inject/memory 895 # echo -12 > actions/MEM_GOING_OFFLINE/error 896 # echo offline > /sys/devices/system/memory/memoryXXX/state 897 bash: echo: write error: Cannot allocate memory 898 899 To compile this code as a module, choose M here: the module will 900 be called memory-notifier-error-inject. 901 902 If unsure, say N. 903 904config DEBUG_PER_CPU_MAPS 905 bool "Debug access to per_cpu maps" 906 depends on DEBUG_KERNEL 907 depends on SMP 908 help 909 Say Y to verify that the per_cpu map being accessed has 910 been set up. This adds a fair amount of code to kernel memory 911 and decreases performance. 912 913 Say N if unsure. 914 915config DEBUG_KMAP_LOCAL 916 bool "Debug kmap_local temporary mappings" 917 depends on DEBUG_KERNEL && KMAP_LOCAL 918 help 919 This option enables additional error checking for the kmap_local 920 infrastructure. Disable for production use. 921 922config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 923 bool 924 925config DEBUG_KMAP_LOCAL_FORCE_MAP 926 bool "Enforce kmap_local temporary mappings" 927 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 928 select KMAP_LOCAL 929 select DEBUG_KMAP_LOCAL 930 help 931 This option enforces temporary mappings through the kmap_local 932 mechanism for non-highmem pages and on non-highmem systems. 933 Disable this for production systems! 934 935config DEBUG_HIGHMEM 936 bool "Highmem debugging" 937 depends on DEBUG_KERNEL && HIGHMEM 938 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 939 select DEBUG_KMAP_LOCAL 940 help 941 This option enables additional error checking for high memory 942 systems. Disable for production systems. 943 944config HAVE_DEBUG_STACKOVERFLOW 945 bool 946 947config DEBUG_STACKOVERFLOW 948 bool "Check for stack overflows" 949 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 950 help 951 Say Y here if you want to check for overflows of kernel, IRQ 952 and exception stacks (if your architecture uses them). This 953 option will show detailed messages if free stack space drops 954 below a certain limit. 955 956 These kinds of bugs usually occur when call-chains in the 957 kernel get too deep, especially when interrupts are 958 involved. 959 960 Use this in cases where you see apparently random memory 961 corruption, especially if it appears in 'struct thread_info' 962 963 If in doubt, say "N". 964 965source "lib/Kconfig.kasan" 966source "lib/Kconfig.kfence" 967source "lib/Kconfig.kmsan" 968 969endmenu # "Memory Debugging" 970 971config DEBUG_SHIRQ 972 bool "Debug shared IRQ handlers" 973 depends on DEBUG_KERNEL 974 help 975 Enable this to generate a spurious interrupt just before a shared 976 interrupt handler is deregistered (generating one when registering 977 is currently disabled). Drivers need to handle this correctly. Some 978 don't and need to be caught. 979 980menu "Debug Oops, Lockups and Hangs" 981 982config PANIC_ON_OOPS 983 bool "Panic on Oops" 984 help 985 Say Y here to enable the kernel to panic when it oopses. This 986 has the same effect as setting oops=panic on the kernel command 987 line. 988 989 This feature is useful to ensure that the kernel does not do 990 anything erroneous after an oops which could result in data 991 corruption or other issues. 992 993 Say N if unsure. 994 995config PANIC_ON_OOPS_VALUE 996 int 997 range 0 1 998 default 0 if !PANIC_ON_OOPS 999 default 1 if PANIC_ON_OOPS 1000 1001config PANIC_TIMEOUT 1002 int "panic timeout" 1003 default 0 1004 help 1005 Set the timeout value (in seconds) until a reboot occurs when 1006 the kernel panics. If n = 0, then we wait forever. A timeout 1007 value n > 0 will wait n seconds before rebooting, while a timeout 1008 value n < 0 will reboot immediately. 1009 1010config LOCKUP_DETECTOR 1011 bool 1012 1013config SOFTLOCKUP_DETECTOR 1014 bool "Detect Soft Lockups" 1015 depends on DEBUG_KERNEL && !S390 1016 select LOCKUP_DETECTOR 1017 help 1018 Say Y here to enable the kernel to act as a watchdog to detect 1019 soft lockups. 1020 1021 Softlockups are bugs that cause the kernel to loop in kernel 1022 mode for more than 20 seconds, without giving other tasks a 1023 chance to run. The current stack trace is displayed upon 1024 detection and the system will stay locked up. 1025 1026config BOOTPARAM_SOFTLOCKUP_PANIC 1027 bool "Panic (Reboot) On Soft Lockups" 1028 depends on SOFTLOCKUP_DETECTOR 1029 help 1030 Say Y here to enable the kernel to panic on "soft lockups", 1031 which are bugs that cause the kernel to loop in kernel 1032 mode for more than 20 seconds (configurable using the watchdog_thresh 1033 sysctl), without giving other tasks a chance to run. 1034 1035 The panic can be used in combination with panic_timeout, 1036 to cause the system to reboot automatically after a 1037 lockup has been detected. This feature is useful for 1038 high-availability systems that have uptime guarantees and 1039 where a lockup must be resolved ASAP. 1040 1041 Say N if unsure. 1042 1043config HAVE_HARDLOCKUP_DETECTOR_BUDDY 1044 bool 1045 depends on SMP 1046 default y 1047 1048# 1049# Global switch whether to build a hardlockup detector at all. It is available 1050# only when the architecture supports at least one implementation. There are 1051# two exceptions. The hardlockup detector is never enabled on: 1052# 1053# s390: it reported many false positives there 1054# 1055# sparc64: has a custom implementation which is not using the common 1056# hardlockup command line options and sysctl interface. 1057# 1058config HARDLOCKUP_DETECTOR 1059 bool "Detect Hard Lockups" 1060 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64 1061 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH 1062 imply HARDLOCKUP_DETECTOR_PERF 1063 imply HARDLOCKUP_DETECTOR_BUDDY 1064 imply HARDLOCKUP_DETECTOR_ARCH 1065 select LOCKUP_DETECTOR 1066 1067 help 1068 Say Y here to enable the kernel to act as a watchdog to detect 1069 hard lockups. 1070 1071 Hardlockups are bugs that cause the CPU to loop in kernel mode 1072 for more than 10 seconds, without letting other interrupts have a 1073 chance to run. The current stack trace is displayed upon detection 1074 and the system will stay locked up. 1075 1076# 1077# Note that arch-specific variants are always preferred. 1078# 1079config HARDLOCKUP_DETECTOR_PREFER_BUDDY 1080 bool "Prefer the buddy CPU hardlockup detector" 1081 depends on HARDLOCKUP_DETECTOR 1082 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY 1083 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1084 help 1085 Say Y here to prefer the buddy hardlockup detector over the perf one. 1086 1087 With the buddy detector, each CPU uses its softlockup hrtimer 1088 to check that the next CPU is processing hrtimer interrupts by 1089 verifying that a counter is increasing. 1090 1091 This hardlockup detector is useful on systems that don't have 1092 an arch-specific hardlockup detector or if resources needed 1093 for the hardlockup detector are better used for other things. 1094 1095config HARDLOCKUP_DETECTOR_PERF 1096 bool 1097 depends on HARDLOCKUP_DETECTOR 1098 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY 1099 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1100 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1101 1102config HARDLOCKUP_DETECTOR_BUDDY 1103 bool 1104 depends on HARDLOCKUP_DETECTOR 1105 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY 1106 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY 1107 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1108 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1109 1110config HARDLOCKUP_DETECTOR_ARCH 1111 bool 1112 depends on HARDLOCKUP_DETECTOR 1113 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH 1114 help 1115 The arch-specific implementation of the hardlockup detector will 1116 be used. 1117 1118# 1119# Both the "perf" and "buddy" hardlockup detectors count hrtimer 1120# interrupts. This config enables functions managing this common code. 1121# 1122config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1123 bool 1124 select SOFTLOCKUP_DETECTOR 1125 1126# 1127# Enables a timestamp based low pass filter to compensate for perf based 1128# hard lockup detection which runs too fast due to turbo modes. 1129# 1130config HARDLOCKUP_CHECK_TIMESTAMP 1131 bool 1132 1133config BOOTPARAM_HARDLOCKUP_PANIC 1134 bool "Panic (Reboot) On Hard Lockups" 1135 depends on HARDLOCKUP_DETECTOR 1136 help 1137 Say Y here to enable the kernel to panic on "hard lockups", 1138 which are bugs that cause the kernel to loop in kernel 1139 mode with interrupts disabled for more than 10 seconds (configurable 1140 using the watchdog_thresh sysctl). 1141 1142 Say N if unsure. 1143 1144config DETECT_HUNG_TASK 1145 bool "Detect Hung Tasks" 1146 depends on DEBUG_KERNEL 1147 default SOFTLOCKUP_DETECTOR 1148 help 1149 Say Y here to enable the kernel to detect "hung tasks", 1150 which are bugs that cause the task to be stuck in 1151 uninterruptible "D" state indefinitely. 1152 1153 When a hung task is detected, the kernel will print the 1154 current stack trace (which you should report), but the 1155 task will stay in uninterruptible state. If lockdep is 1156 enabled then all held locks will also be reported. This 1157 feature has negligible overhead. 1158 1159config DEFAULT_HUNG_TASK_TIMEOUT 1160 int "Default timeout for hung task detection (in seconds)" 1161 depends on DETECT_HUNG_TASK 1162 default 120 1163 help 1164 This option controls the default timeout (in seconds) used 1165 to determine when a task has become non-responsive and should 1166 be considered hung. 1167 1168 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1169 sysctl or by writing a value to 1170 /proc/sys/kernel/hung_task_timeout_secs. 1171 1172 A timeout of 0 disables the check. The default is two minutes. 1173 Keeping the default should be fine in most cases. 1174 1175config BOOTPARAM_HUNG_TASK_PANIC 1176 bool "Panic (Reboot) On Hung Tasks" 1177 depends on DETECT_HUNG_TASK 1178 help 1179 Say Y here to enable the kernel to panic on "hung tasks", 1180 which are bugs that cause the kernel to leave a task stuck 1181 in uninterruptible "D" state. 1182 1183 The panic can be used in combination with panic_timeout, 1184 to cause the system to reboot automatically after a 1185 hung task has been detected. This feature is useful for 1186 high-availability systems that have uptime guarantees and 1187 where a hung tasks must be resolved ASAP. 1188 1189 Say N if unsure. 1190 1191config WQ_WATCHDOG 1192 bool "Detect Workqueue Stalls" 1193 depends on DEBUG_KERNEL 1194 help 1195 Say Y here to enable stall detection on workqueues. If a 1196 worker pool doesn't make forward progress on a pending work 1197 item for over a given amount of time, 30s by default, a 1198 warning message is printed along with dump of workqueue 1199 state. This can be configured through kernel parameter 1200 "workqueue.watchdog_thresh" and its sysfs counterpart. 1201 1202config WQ_CPU_INTENSIVE_REPORT 1203 bool "Report per-cpu work items which hog CPU for too long" 1204 depends on DEBUG_KERNEL 1205 help 1206 Say Y here to enable reporting of concurrency-managed per-cpu work 1207 items that hog CPUs for longer than 1208 workqueue.cpu_intensive_thresh_us. Workqueue automatically 1209 detects and excludes them from concurrency management to prevent 1210 them from stalling other per-cpu work items. Occassional 1211 triggering may not necessarily indicate a problem. Repeated 1212 triggering likely indicates that the work item should be switched 1213 to use an unbound workqueue. 1214 1215config TEST_LOCKUP 1216 tristate "Test module to generate lockups" 1217 depends on m 1218 help 1219 This builds the "test_lockup" module that helps to make sure 1220 that watchdogs and lockup detectors are working properly. 1221 1222 Depending on module parameters it could emulate soft or hard 1223 lockup, "hung task", or locking arbitrary lock for a long time. 1224 Also it could generate series of lockups with cooling-down periods. 1225 1226 If unsure, say N. 1227 1228endmenu # "Debug lockups and hangs" 1229 1230menu "Scheduler Debugging" 1231 1232config SCHED_DEBUG 1233 bool "Collect scheduler debugging info" 1234 depends on DEBUG_KERNEL && DEBUG_FS 1235 default y 1236 help 1237 If you say Y here, the /sys/kernel/debug/sched file will be provided 1238 that can help debug the scheduler. The runtime overhead of this 1239 option is minimal. 1240 1241config SCHED_INFO 1242 bool 1243 default n 1244 1245config SCHEDSTATS 1246 bool "Collect scheduler statistics" 1247 depends on DEBUG_KERNEL && PROC_FS 1248 select SCHED_INFO 1249 help 1250 If you say Y here, additional code will be inserted into the 1251 scheduler and related routines to collect statistics about 1252 scheduler behavior and provide them in /proc/schedstat. These 1253 stats may be useful for both tuning and debugging the scheduler 1254 If you aren't debugging the scheduler or trying to tune a specific 1255 application, you can say N to avoid the very slight overhead 1256 this adds. 1257 1258endmenu 1259 1260config DEBUG_TIMEKEEPING 1261 bool "Enable extra timekeeping sanity checking" 1262 help 1263 This option will enable additional timekeeping sanity checks 1264 which may be helpful when diagnosing issues where timekeeping 1265 problems are suspected. 1266 1267 This may include checks in the timekeeping hotpaths, so this 1268 option may have a (very small) performance impact to some 1269 workloads. 1270 1271 If unsure, say N. 1272 1273config DEBUG_PREEMPT 1274 bool "Debug preemptible kernel" 1275 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1276 help 1277 If you say Y here then the kernel will use a debug variant of the 1278 commonly used smp_processor_id() function and will print warnings 1279 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1280 will detect preemption count underflows. 1281 1282 This option has potential to introduce high runtime overhead, 1283 depending on workload as it triggers debugging routines for each 1284 this_cpu operation. It should only be used for debugging purposes. 1285 1286menu "Lock Debugging (spinlocks, mutexes, etc...)" 1287 1288config LOCK_DEBUGGING_SUPPORT 1289 bool 1290 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1291 default y 1292 1293config PROVE_LOCKING 1294 bool "Lock debugging: prove locking correctness" 1295 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1296 select LOCKDEP 1297 select DEBUG_SPINLOCK 1298 select DEBUG_MUTEXES if !PREEMPT_RT 1299 select DEBUG_RT_MUTEXES if RT_MUTEXES 1300 select DEBUG_RWSEMS 1301 select DEBUG_WW_MUTEX_SLOWPATH 1302 select DEBUG_LOCK_ALLOC 1303 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1304 select TRACE_IRQFLAGS 1305 default n 1306 help 1307 This feature enables the kernel to prove that all locking 1308 that occurs in the kernel runtime is mathematically 1309 correct: that under no circumstance could an arbitrary (and 1310 not yet triggered) combination of observed locking 1311 sequences (on an arbitrary number of CPUs, running an 1312 arbitrary number of tasks and interrupt contexts) cause a 1313 deadlock. 1314 1315 In short, this feature enables the kernel to report locking 1316 related deadlocks before they actually occur. 1317 1318 The proof does not depend on how hard and complex a 1319 deadlock scenario would be to trigger: how many 1320 participant CPUs, tasks and irq-contexts would be needed 1321 for it to trigger. The proof also does not depend on 1322 timing: if a race and a resulting deadlock is possible 1323 theoretically (no matter how unlikely the race scenario 1324 is), it will be proven so and will immediately be 1325 reported by the kernel (once the event is observed that 1326 makes the deadlock theoretically possible). 1327 1328 If a deadlock is impossible (i.e. the locking rules, as 1329 observed by the kernel, are mathematically correct), the 1330 kernel reports nothing. 1331 1332 NOTE: this feature can also be enabled for rwlocks, mutexes 1333 and rwsems - in which case all dependencies between these 1334 different locking variants are observed and mapped too, and 1335 the proof of observed correctness is also maintained for an 1336 arbitrary combination of these separate locking variants. 1337 1338 For more details, see Documentation/locking/lockdep-design.rst. 1339 1340config PROVE_RAW_LOCK_NESTING 1341 bool "Enable raw_spinlock - spinlock nesting checks" 1342 depends on PROVE_LOCKING 1343 default n 1344 help 1345 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1346 that the lock nesting rules for PREEMPT_RT enabled kernels are 1347 not violated. 1348 1349 NOTE: There are known nesting problems. So if you enable this 1350 option expect lockdep splats until these problems have been fully 1351 addressed which is work in progress. This config switch allows to 1352 identify and analyze these problems. It will be removed and the 1353 check permanently enabled once the main issues have been fixed. 1354 1355 If unsure, select N. 1356 1357config LOCK_STAT 1358 bool "Lock usage statistics" 1359 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1360 select LOCKDEP 1361 select DEBUG_SPINLOCK 1362 select DEBUG_MUTEXES if !PREEMPT_RT 1363 select DEBUG_RT_MUTEXES if RT_MUTEXES 1364 select DEBUG_LOCK_ALLOC 1365 default n 1366 help 1367 This feature enables tracking lock contention points 1368 1369 For more details, see Documentation/locking/lockstat.rst 1370 1371 This also enables lock events required by "perf lock", 1372 subcommand of perf. 1373 If you want to use "perf lock", you also need to turn on 1374 CONFIG_EVENT_TRACING. 1375 1376 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1377 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1378 1379config DEBUG_RT_MUTEXES 1380 bool "RT Mutex debugging, deadlock detection" 1381 depends on DEBUG_KERNEL && RT_MUTEXES 1382 help 1383 This allows rt mutex semantics violations and rt mutex related 1384 deadlocks (lockups) to be detected and reported automatically. 1385 1386config DEBUG_SPINLOCK 1387 bool "Spinlock and rw-lock debugging: basic checks" 1388 depends on DEBUG_KERNEL 1389 select UNINLINE_SPIN_UNLOCK 1390 help 1391 Say Y here and build SMP to catch missing spinlock initialization 1392 and certain other kinds of spinlock errors commonly made. This is 1393 best used in conjunction with the NMI watchdog so that spinlock 1394 deadlocks are also debuggable. 1395 1396config DEBUG_MUTEXES 1397 bool "Mutex debugging: basic checks" 1398 depends on DEBUG_KERNEL && !PREEMPT_RT 1399 help 1400 This feature allows mutex semantics violations to be detected and 1401 reported. 1402 1403config DEBUG_WW_MUTEX_SLOWPATH 1404 bool "Wait/wound mutex debugging: Slowpath testing" 1405 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1406 select DEBUG_LOCK_ALLOC 1407 select DEBUG_SPINLOCK 1408 select DEBUG_MUTEXES if !PREEMPT_RT 1409 select DEBUG_RT_MUTEXES if PREEMPT_RT 1410 help 1411 This feature enables slowpath testing for w/w mutex users by 1412 injecting additional -EDEADLK wound/backoff cases. Together with 1413 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1414 will test all possible w/w mutex interface abuse with the 1415 exception of simply not acquiring all the required locks. 1416 Note that this feature can introduce significant overhead, so 1417 it really should not be enabled in a production or distro kernel, 1418 even a debug kernel. If you are a driver writer, enable it. If 1419 you are a distro, do not. 1420 1421config DEBUG_RWSEMS 1422 bool "RW Semaphore debugging: basic checks" 1423 depends on DEBUG_KERNEL 1424 help 1425 This debugging feature allows mismatched rw semaphore locks 1426 and unlocks to be detected and reported. 1427 1428config DEBUG_LOCK_ALLOC 1429 bool "Lock debugging: detect incorrect freeing of live locks" 1430 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1431 select DEBUG_SPINLOCK 1432 select DEBUG_MUTEXES if !PREEMPT_RT 1433 select DEBUG_RT_MUTEXES if RT_MUTEXES 1434 select LOCKDEP 1435 help 1436 This feature will check whether any held lock (spinlock, rwlock, 1437 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1438 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1439 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1440 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1441 held during task exit. 1442 1443config LOCKDEP 1444 bool 1445 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1446 select STACKTRACE 1447 select KALLSYMS 1448 select KALLSYMS_ALL 1449 1450config LOCKDEP_SMALL 1451 bool 1452 1453config LOCKDEP_BITS 1454 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1455 depends on LOCKDEP && !LOCKDEP_SMALL 1456 range 10 30 1457 default 15 1458 help 1459 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1460 1461config LOCKDEP_CHAINS_BITS 1462 int "Bitsize for MAX_LOCKDEP_CHAINS" 1463 depends on LOCKDEP && !LOCKDEP_SMALL 1464 range 10 30 1465 default 16 1466 help 1467 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1468 1469config LOCKDEP_STACK_TRACE_BITS 1470 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1471 depends on LOCKDEP && !LOCKDEP_SMALL 1472 range 10 30 1473 default 19 1474 help 1475 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1476 1477config LOCKDEP_STACK_TRACE_HASH_BITS 1478 int "Bitsize for STACK_TRACE_HASH_SIZE" 1479 depends on LOCKDEP && !LOCKDEP_SMALL 1480 range 10 30 1481 default 14 1482 help 1483 Try increasing this value if you need large STACK_TRACE_HASH_SIZE. 1484 1485config LOCKDEP_CIRCULAR_QUEUE_BITS 1486 int "Bitsize for elements in circular_queue struct" 1487 depends on LOCKDEP 1488 range 10 30 1489 default 12 1490 help 1491 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1492 1493config DEBUG_LOCKDEP 1494 bool "Lock dependency engine debugging" 1495 depends on DEBUG_KERNEL && LOCKDEP 1496 select DEBUG_IRQFLAGS 1497 help 1498 If you say Y here, the lock dependency engine will do 1499 additional runtime checks to debug itself, at the price 1500 of more runtime overhead. 1501 1502config DEBUG_ATOMIC_SLEEP 1503 bool "Sleep inside atomic section checking" 1504 select PREEMPT_COUNT 1505 depends on DEBUG_KERNEL 1506 depends on !ARCH_NO_PREEMPT 1507 help 1508 If you say Y here, various routines which may sleep will become very 1509 noisy if they are called inside atomic sections: when a spinlock is 1510 held, inside an rcu read side critical section, inside preempt disabled 1511 sections, inside an interrupt, etc... 1512 1513config DEBUG_LOCKING_API_SELFTESTS 1514 bool "Locking API boot-time self-tests" 1515 depends on DEBUG_KERNEL 1516 help 1517 Say Y here if you want the kernel to run a short self-test during 1518 bootup. The self-test checks whether common types of locking bugs 1519 are detected by debugging mechanisms or not. (if you disable 1520 lock debugging then those bugs won't be detected of course.) 1521 The following locking APIs are covered: spinlocks, rwlocks, 1522 mutexes and rwsems. 1523 1524config LOCK_TORTURE_TEST 1525 tristate "torture tests for locking" 1526 depends on DEBUG_KERNEL 1527 select TORTURE_TEST 1528 help 1529 This option provides a kernel module that runs torture tests 1530 on kernel locking primitives. The kernel module may be built 1531 after the fact on the running kernel to be tested, if desired. 1532 1533 Say Y here if you want kernel locking-primitive torture tests 1534 to be built into the kernel. 1535 Say M if you want these torture tests to build as a module. 1536 Say N if you are unsure. 1537 1538config WW_MUTEX_SELFTEST 1539 tristate "Wait/wound mutex selftests" 1540 help 1541 This option provides a kernel module that runs tests on the 1542 on the struct ww_mutex locking API. 1543 1544 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1545 with this test harness. 1546 1547 Say M if you want these self tests to build as a module. 1548 Say N if you are unsure. 1549 1550config SCF_TORTURE_TEST 1551 tristate "torture tests for smp_call_function*()" 1552 depends on DEBUG_KERNEL 1553 select TORTURE_TEST 1554 help 1555 This option provides a kernel module that runs torture tests 1556 on the smp_call_function() family of primitives. The kernel 1557 module may be built after the fact on the running kernel to 1558 be tested, if desired. 1559 1560config CSD_LOCK_WAIT_DEBUG 1561 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1562 depends on DEBUG_KERNEL 1563 depends on 64BIT 1564 default n 1565 help 1566 This option enables debug prints when CPUs are slow to respond 1567 to the smp_call_function*() IPI wrappers. These debug prints 1568 include the IPI handler function currently executing (if any) 1569 and relevant stack traces. 1570 1571config CSD_LOCK_WAIT_DEBUG_DEFAULT 1572 bool "Default csd_lock_wait() debugging on at boot time" 1573 depends on CSD_LOCK_WAIT_DEBUG 1574 depends on 64BIT 1575 default n 1576 help 1577 This option causes the csdlock_debug= kernel boot parameter to 1578 default to 1 (basic debugging) instead of 0 (no debugging). 1579 1580endmenu # lock debugging 1581 1582config TRACE_IRQFLAGS 1583 depends on TRACE_IRQFLAGS_SUPPORT 1584 bool 1585 help 1586 Enables hooks to interrupt enabling and disabling for 1587 either tracing or lock debugging. 1588 1589config TRACE_IRQFLAGS_NMI 1590 def_bool y 1591 depends on TRACE_IRQFLAGS 1592 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1593 1594config NMI_CHECK_CPU 1595 bool "Debugging for CPUs failing to respond to backtrace requests" 1596 depends on DEBUG_KERNEL 1597 depends on X86 1598 default n 1599 help 1600 Enables debug prints when a CPU fails to respond to a given 1601 backtrace NMI. These prints provide some reasons why a CPU 1602 might legitimately be failing to respond, for example, if it 1603 is offline of if ignore_nmis is set. 1604 1605config DEBUG_IRQFLAGS 1606 bool "Debug IRQ flag manipulation" 1607 help 1608 Enables checks for potentially unsafe enabling or disabling of 1609 interrupts, such as calling raw_local_irq_restore() when interrupts 1610 are enabled. 1611 1612config STACKTRACE 1613 bool "Stack backtrace support" 1614 depends on STACKTRACE_SUPPORT 1615 help 1616 This option causes the kernel to create a /proc/pid/stack for 1617 every process, showing its current stack trace. 1618 It is also used by various kernel debugging features that require 1619 stack trace generation. 1620 1621config WARN_ALL_UNSEEDED_RANDOM 1622 bool "Warn for all uses of unseeded randomness" 1623 default n 1624 help 1625 Some parts of the kernel contain bugs relating to their use of 1626 cryptographically secure random numbers before it's actually possible 1627 to generate those numbers securely. This setting ensures that these 1628 flaws don't go unnoticed, by enabling a message, should this ever 1629 occur. This will allow people with obscure setups to know when things 1630 are going wrong, so that they might contact developers about fixing 1631 it. 1632 1633 Unfortunately, on some models of some architectures getting 1634 a fully seeded CRNG is extremely difficult, and so this can 1635 result in dmesg getting spammed for a surprisingly long 1636 time. This is really bad from a security perspective, and 1637 so architecture maintainers really need to do what they can 1638 to get the CRNG seeded sooner after the system is booted. 1639 However, since users cannot do anything actionable to 1640 address this, by default this option is disabled. 1641 1642 Say Y here if you want to receive warnings for all uses of 1643 unseeded randomness. This will be of use primarily for 1644 those developers interested in improving the security of 1645 Linux kernels running on their architecture (or 1646 subarchitecture). 1647 1648config DEBUG_KOBJECT 1649 bool "kobject debugging" 1650 depends on DEBUG_KERNEL 1651 help 1652 If you say Y here, some extra kobject debugging messages will be sent 1653 to the syslog. 1654 1655config DEBUG_KOBJECT_RELEASE 1656 bool "kobject release debugging" 1657 depends on DEBUG_OBJECTS_TIMERS 1658 help 1659 kobjects are reference counted objects. This means that their 1660 last reference count put is not predictable, and the kobject can 1661 live on past the point at which a driver decides to drop its 1662 initial reference to the kobject gained on allocation. An 1663 example of this would be a struct device which has just been 1664 unregistered. 1665 1666 However, some buggy drivers assume that after such an operation, 1667 the memory backing the kobject can be immediately freed. This 1668 goes completely against the principles of a refcounted object. 1669 1670 If you say Y here, the kernel will delay the release of kobjects 1671 on the last reference count to improve the visibility of this 1672 kind of kobject release bug. 1673 1674config HAVE_DEBUG_BUGVERBOSE 1675 bool 1676 1677menu "Debug kernel data structures" 1678 1679config DEBUG_LIST 1680 bool "Debug linked list manipulation" 1681 depends on DEBUG_KERNEL 1682 select LIST_HARDENED 1683 help 1684 Enable this to turn on extended checks in the linked-list walking 1685 routines. 1686 1687 This option trades better quality error reports for performance, and 1688 is more suitable for kernel debugging. If you care about performance, 1689 you should only enable CONFIG_LIST_HARDENED instead. 1690 1691 If unsure, say N. 1692 1693config DEBUG_PLIST 1694 bool "Debug priority linked list manipulation" 1695 depends on DEBUG_KERNEL 1696 help 1697 Enable this to turn on extended checks in the priority-ordered 1698 linked-list (plist) walking routines. This checks the entire 1699 list multiple times during each manipulation. 1700 1701 If unsure, say N. 1702 1703config DEBUG_SG 1704 bool "Debug SG table operations" 1705 depends on DEBUG_KERNEL 1706 help 1707 Enable this to turn on checks on scatter-gather tables. This can 1708 help find problems with drivers that do not properly initialize 1709 their sg tables. 1710 1711 If unsure, say N. 1712 1713config DEBUG_NOTIFIERS 1714 bool "Debug notifier call chains" 1715 depends on DEBUG_KERNEL 1716 help 1717 Enable this to turn on sanity checking for notifier call chains. 1718 This is most useful for kernel developers to make sure that 1719 modules properly unregister themselves from notifier chains. 1720 This is a relatively cheap check but if you care about maximum 1721 performance, say N. 1722 1723config DEBUG_MAPLE_TREE 1724 bool "Debug maple trees" 1725 depends on DEBUG_KERNEL 1726 help 1727 Enable maple tree debugging information and extra validations. 1728 1729 If unsure, say N. 1730 1731endmenu 1732 1733source "kernel/rcu/Kconfig.debug" 1734 1735config DEBUG_WQ_FORCE_RR_CPU 1736 bool "Force round-robin CPU selection for unbound work items" 1737 depends on DEBUG_KERNEL 1738 default n 1739 help 1740 Workqueue used to implicitly guarantee that work items queued 1741 without explicit CPU specified are put on the local CPU. This 1742 guarantee is no longer true and while local CPU is still 1743 preferred work items may be put on foreign CPUs. Kernel 1744 parameter "workqueue.debug_force_rr_cpu" is added to force 1745 round-robin CPU selection to flush out usages which depend on the 1746 now broken guarantee. This config option enables the debug 1747 feature by default. When enabled, memory and cache locality will 1748 be impacted. 1749 1750config CPU_HOTPLUG_STATE_CONTROL 1751 bool "Enable CPU hotplug state control" 1752 depends on DEBUG_KERNEL 1753 depends on HOTPLUG_CPU 1754 default n 1755 help 1756 Allows to write steps between "offline" and "online" to the CPUs 1757 sysfs target file so states can be stepped granular. This is a debug 1758 option for now as the hotplug machinery cannot be stopped and 1759 restarted at arbitrary points yet. 1760 1761 Say N if your are unsure. 1762 1763config LATENCYTOP 1764 bool "Latency measuring infrastructure" 1765 depends on DEBUG_KERNEL 1766 depends on STACKTRACE_SUPPORT 1767 depends on PROC_FS 1768 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1769 select KALLSYMS 1770 select KALLSYMS_ALL 1771 select STACKTRACE 1772 select SCHEDSTATS 1773 help 1774 Enable this option if you want to use the LatencyTOP tool 1775 to find out which userspace is blocking on what kernel operations. 1776 1777config DEBUG_CGROUP_REF 1778 bool "Disable inlining of cgroup css reference count functions" 1779 depends on DEBUG_KERNEL 1780 depends on CGROUPS 1781 depends on KPROBES 1782 default n 1783 help 1784 Force cgroup css reference count functions to not be inlined so 1785 that they can be kprobed for debugging. 1786 1787source "kernel/trace/Kconfig" 1788 1789config PROVIDE_OHCI1394_DMA_INIT 1790 bool "Remote debugging over FireWire early on boot" 1791 depends on PCI && X86 1792 help 1793 If you want to debug problems which hang or crash the kernel early 1794 on boot and the crashing machine has a FireWire port, you can use 1795 this feature to remotely access the memory of the crashed machine 1796 over FireWire. This employs remote DMA as part of the OHCI1394 1797 specification which is now the standard for FireWire controllers. 1798 1799 With remote DMA, you can monitor the printk buffer remotely using 1800 firescope and access all memory below 4GB using fireproxy from gdb. 1801 Even controlling a kernel debugger is possible using remote DMA. 1802 1803 Usage: 1804 1805 If ohci1394_dma=early is used as boot parameter, it will initialize 1806 all OHCI1394 controllers which are found in the PCI config space. 1807 1808 As all changes to the FireWire bus such as enabling and disabling 1809 devices cause a bus reset and thereby disable remote DMA for all 1810 devices, be sure to have the cable plugged and FireWire enabled on 1811 the debugging host before booting the debug target for debugging. 1812 1813 This code (~1k) is freed after boot. By then, the firewire stack 1814 in charge of the OHCI-1394 controllers should be used instead. 1815 1816 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1817 1818source "samples/Kconfig" 1819 1820config ARCH_HAS_DEVMEM_IS_ALLOWED 1821 bool 1822 1823config STRICT_DEVMEM 1824 bool "Filter access to /dev/mem" 1825 depends on MMU && DEVMEM 1826 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1827 default y if PPC || X86 || ARM64 1828 help 1829 If this option is disabled, you allow userspace (root) access to all 1830 of memory, including kernel and userspace memory. Accidental 1831 access to this is obviously disastrous, but specific access can 1832 be used by people debugging the kernel. Note that with PAT support 1833 enabled, even in this case there are restrictions on /dev/mem 1834 use due to the cache aliasing requirements. 1835 1836 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1837 file only allows userspace access to PCI space and the BIOS code and 1838 data regions. This is sufficient for dosemu and X and all common 1839 users of /dev/mem. 1840 1841 If in doubt, say Y. 1842 1843config IO_STRICT_DEVMEM 1844 bool "Filter I/O access to /dev/mem" 1845 depends on STRICT_DEVMEM 1846 help 1847 If this option is disabled, you allow userspace (root) access to all 1848 io-memory regardless of whether a driver is actively using that 1849 range. Accidental access to this is obviously disastrous, but 1850 specific access can be used by people debugging kernel drivers. 1851 1852 If this option is switched on, the /dev/mem file only allows 1853 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1854 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1855 if the driver using a given range cannot be disabled. 1856 1857 If in doubt, say Y. 1858 1859menu "$(SRCARCH) Debugging" 1860 1861source "arch/$(SRCARCH)/Kconfig.debug" 1862 1863endmenu 1864 1865menu "Kernel Testing and Coverage" 1866 1867source "lib/kunit/Kconfig" 1868 1869config NOTIFIER_ERROR_INJECTION 1870 tristate "Notifier error injection" 1871 depends on DEBUG_KERNEL 1872 select DEBUG_FS 1873 help 1874 This option provides the ability to inject artificial errors to 1875 specified notifier chain callbacks. It is useful to test the error 1876 handling of notifier call chain failures. 1877 1878 Say N if unsure. 1879 1880config PM_NOTIFIER_ERROR_INJECT 1881 tristate "PM notifier error injection module" 1882 depends on PM && NOTIFIER_ERROR_INJECTION 1883 default m if PM_DEBUG 1884 help 1885 This option provides the ability to inject artificial errors to 1886 PM notifier chain callbacks. It is controlled through debugfs 1887 interface /sys/kernel/debug/notifier-error-inject/pm 1888 1889 If the notifier call chain should be failed with some events 1890 notified, write the error code to "actions/<notifier event>/error". 1891 1892 Example: Inject PM suspend error (-12 = -ENOMEM) 1893 1894 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1895 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1896 # echo mem > /sys/power/state 1897 bash: echo: write error: Cannot allocate memory 1898 1899 To compile this code as a module, choose M here: the module will 1900 be called pm-notifier-error-inject. 1901 1902 If unsure, say N. 1903 1904config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1905 tristate "OF reconfig notifier error injection module" 1906 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1907 help 1908 This option provides the ability to inject artificial errors to 1909 OF reconfig notifier chain callbacks. It is controlled 1910 through debugfs interface under 1911 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1912 1913 If the notifier call chain should be failed with some events 1914 notified, write the error code to "actions/<notifier event>/error". 1915 1916 To compile this code as a module, choose M here: the module will 1917 be called of-reconfig-notifier-error-inject. 1918 1919 If unsure, say N. 1920 1921config NETDEV_NOTIFIER_ERROR_INJECT 1922 tristate "Netdev notifier error injection module" 1923 depends on NET && NOTIFIER_ERROR_INJECTION 1924 help 1925 This option provides the ability to inject artificial errors to 1926 netdevice notifier chain callbacks. It is controlled through debugfs 1927 interface /sys/kernel/debug/notifier-error-inject/netdev 1928 1929 If the notifier call chain should be failed with some events 1930 notified, write the error code to "actions/<notifier event>/error". 1931 1932 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1933 1934 # cd /sys/kernel/debug/notifier-error-inject/netdev 1935 # echo -22 > actions/NETDEV_CHANGEMTU/error 1936 # ip link set eth0 mtu 1024 1937 RTNETLINK answers: Invalid argument 1938 1939 To compile this code as a module, choose M here: the module will 1940 be called netdev-notifier-error-inject. 1941 1942 If unsure, say N. 1943 1944config FUNCTION_ERROR_INJECTION 1945 bool "Fault-injections of functions" 1946 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1947 help 1948 Add fault injections into various functions that are annotated with 1949 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1950 value of these functions. This is useful to test error paths of code. 1951 1952 If unsure, say N 1953 1954config FAULT_INJECTION 1955 bool "Fault-injection framework" 1956 depends on DEBUG_KERNEL 1957 help 1958 Provide fault-injection framework. 1959 For more details, see Documentation/fault-injection/. 1960 1961config FAILSLAB 1962 bool "Fault-injection capability for kmalloc" 1963 depends on FAULT_INJECTION 1964 depends on SLAB || SLUB 1965 help 1966 Provide fault-injection capability for kmalloc. 1967 1968config FAIL_PAGE_ALLOC 1969 bool "Fault-injection capability for alloc_pages()" 1970 depends on FAULT_INJECTION 1971 help 1972 Provide fault-injection capability for alloc_pages(). 1973 1974config FAULT_INJECTION_USERCOPY 1975 bool "Fault injection capability for usercopy functions" 1976 depends on FAULT_INJECTION 1977 help 1978 Provides fault-injection capability to inject failures 1979 in usercopy functions (copy_from_user(), get_user(), ...). 1980 1981config FAIL_MAKE_REQUEST 1982 bool "Fault-injection capability for disk IO" 1983 depends on FAULT_INJECTION && BLOCK 1984 help 1985 Provide fault-injection capability for disk IO. 1986 1987config FAIL_IO_TIMEOUT 1988 bool "Fault-injection capability for faking disk interrupts" 1989 depends on FAULT_INJECTION && BLOCK 1990 help 1991 Provide fault-injection capability on end IO handling. This 1992 will make the block layer "forget" an interrupt as configured, 1993 thus exercising the error handling. 1994 1995 Only works with drivers that use the generic timeout handling, 1996 for others it won't do anything. 1997 1998config FAIL_FUTEX 1999 bool "Fault-injection capability for futexes" 2000 select DEBUG_FS 2001 depends on FAULT_INJECTION && FUTEX 2002 help 2003 Provide fault-injection capability for futexes. 2004 2005config FAULT_INJECTION_DEBUG_FS 2006 bool "Debugfs entries for fault-injection capabilities" 2007 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 2008 help 2009 Enable configuration of fault-injection capabilities via debugfs. 2010 2011config FAIL_FUNCTION 2012 bool "Fault-injection capability for functions" 2013 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 2014 help 2015 Provide function-based fault-injection capability. 2016 This will allow you to override a specific function with a return 2017 with given return value. As a result, function caller will see 2018 an error value and have to handle it. This is useful to test the 2019 error handling in various subsystems. 2020 2021config FAIL_MMC_REQUEST 2022 bool "Fault-injection capability for MMC IO" 2023 depends on FAULT_INJECTION_DEBUG_FS && MMC 2024 help 2025 Provide fault-injection capability for MMC IO. 2026 This will make the mmc core return data errors. This is 2027 useful to test the error handling in the mmc block device 2028 and to test how the mmc host driver handles retries from 2029 the block device. 2030 2031config FAIL_SUNRPC 2032 bool "Fault-injection capability for SunRPC" 2033 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2034 help 2035 Provide fault-injection capability for SunRPC and 2036 its consumers. 2037 2038config FAULT_INJECTION_CONFIGFS 2039 bool "Configfs interface for fault-injection capabilities" 2040 depends on FAULT_INJECTION 2041 select CONFIGFS_FS 2042 help 2043 This option allows configfs-based drivers to dynamically configure 2044 fault-injection via configfs. Each parameter for driver-specific 2045 fault-injection can be made visible as a configfs attribute in a 2046 configfs group. 2047 2048 2049config FAULT_INJECTION_STACKTRACE_FILTER 2050 bool "stacktrace filter for fault-injection capabilities" 2051 depends on FAULT_INJECTION 2052 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT 2053 select STACKTRACE 2054 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2055 help 2056 Provide stacktrace filter for fault-injection capabilities 2057 2058config ARCH_HAS_KCOV 2059 bool 2060 help 2061 An architecture should select this when it can successfully 2062 build and run with CONFIG_KCOV. This typically requires 2063 disabling instrumentation for some early boot code. 2064 2065config CC_HAS_SANCOV_TRACE_PC 2066 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2067 2068 2069config KCOV 2070 bool "Code coverage for fuzzing" 2071 depends on ARCH_HAS_KCOV 2072 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2073 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2074 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2075 select DEBUG_FS 2076 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2077 select OBJTOOL if HAVE_NOINSTR_HACK 2078 help 2079 KCOV exposes kernel code coverage information in a form suitable 2080 for coverage-guided fuzzing (randomized testing). 2081 2082 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2083 different machines and across reboots. If you need stable PC values, 2084 disable RANDOMIZE_BASE. 2085 2086 For more details, see Documentation/dev-tools/kcov.rst. 2087 2088config KCOV_ENABLE_COMPARISONS 2089 bool "Enable comparison operands collection by KCOV" 2090 depends on KCOV 2091 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2092 help 2093 KCOV also exposes operands of every comparison in the instrumented 2094 code along with operand sizes and PCs of the comparison instructions. 2095 These operands can be used by fuzzing engines to improve the quality 2096 of fuzzing coverage. 2097 2098config KCOV_INSTRUMENT_ALL 2099 bool "Instrument all code by default" 2100 depends on KCOV 2101 default y 2102 help 2103 If you are doing generic system call fuzzing (like e.g. syzkaller), 2104 then you will want to instrument the whole kernel and you should 2105 say y here. If you are doing more targeted fuzzing (like e.g. 2106 filesystem fuzzing with AFL) then you will want to enable coverage 2107 for more specific subsets of files, and should say n here. 2108 2109config KCOV_IRQ_AREA_SIZE 2110 hex "Size of interrupt coverage collection area in words" 2111 depends on KCOV 2112 default 0x40000 2113 help 2114 KCOV uses preallocated per-cpu areas to collect coverage from 2115 soft interrupts. This specifies the size of those areas in the 2116 number of unsigned long words. 2117 2118menuconfig RUNTIME_TESTING_MENU 2119 bool "Runtime Testing" 2120 def_bool y 2121 2122if RUNTIME_TESTING_MENU 2123 2124config TEST_DHRY 2125 tristate "Dhrystone benchmark test" 2126 help 2127 Enable this to include the Dhrystone 2.1 benchmark. This test 2128 calculates the number of Dhrystones per second, and the number of 2129 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided 2130 by 1757 (the number of Dhrystones per second obtained on the VAX 2131 11/780, nominally a 1 MIPS machine). 2132 2133 To run the benchmark, it needs to be enabled explicitly, either from 2134 the kernel command line (when built-in), or from userspace (when 2135 built-in or modular. 2136 2137 Run once during kernel boot: 2138 2139 test_dhry.run 2140 2141 Set number of iterations from kernel command line: 2142 2143 test_dhry.iterations=<n> 2144 2145 Set number of iterations from userspace: 2146 2147 echo <n> > /sys/module/test_dhry/parameters/iterations 2148 2149 Trigger manual run from userspace: 2150 2151 echo y > /sys/module/test_dhry/parameters/run 2152 2153 If the number of iterations is <= 0, the test will devise a suitable 2154 number of iterations (test runs for at least 2s) automatically. 2155 This process takes ca. 4s. 2156 2157 If unsure, say N. 2158 2159config LKDTM 2160 tristate "Linux Kernel Dump Test Tool Module" 2161 depends on DEBUG_FS 2162 help 2163 This module enables testing of the different dumping mechanisms by 2164 inducing system failures at predefined crash points. 2165 If you don't need it: say N 2166 Choose M here to compile this code as a module. The module will be 2167 called lkdtm. 2168 2169 Documentation on how to use the module can be found in 2170 Documentation/fault-injection/provoke-crashes.rst 2171 2172config CPUMASK_KUNIT_TEST 2173 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2174 depends on KUNIT 2175 default KUNIT_ALL_TESTS 2176 help 2177 Enable to turn on cpumask tests, running at boot or module load time. 2178 2179 For more information on KUnit and unit tests in general, please refer 2180 to the KUnit documentation in Documentation/dev-tools/kunit/. 2181 2182 If unsure, say N. 2183 2184config TEST_LIST_SORT 2185 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2186 depends on KUNIT 2187 default KUNIT_ALL_TESTS 2188 help 2189 Enable this to turn on 'list_sort()' function test. This test is 2190 executed only once during system boot (so affects only boot time), 2191 or at module load time. 2192 2193 If unsure, say N. 2194 2195config TEST_MIN_HEAP 2196 tristate "Min heap test" 2197 depends on DEBUG_KERNEL || m 2198 help 2199 Enable this to turn on min heap function tests. This test is 2200 executed only once during system boot (so affects only boot time), 2201 or at module load time. 2202 2203 If unsure, say N. 2204 2205config TEST_SORT 2206 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2207 depends on KUNIT 2208 default KUNIT_ALL_TESTS 2209 help 2210 This option enables the self-test function of 'sort()' at boot, 2211 or at module load time. 2212 2213 If unsure, say N. 2214 2215config TEST_DIV64 2216 tristate "64bit/32bit division and modulo test" 2217 depends on DEBUG_KERNEL || m 2218 help 2219 Enable this to turn on 'do_div()' function test. This test is 2220 executed only once during system boot (so affects only boot time), 2221 or at module load time. 2222 2223 If unsure, say N. 2224 2225config TEST_IOV_ITER 2226 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS 2227 depends on KUNIT 2228 default KUNIT_ALL_TESTS 2229 help 2230 Enable this to turn on testing of the operation of the I/O iterator 2231 (iov_iter). This test is executed only once during system boot (so 2232 affects only boot time), or at module load time. 2233 2234 If unsure, say N. 2235 2236config KPROBES_SANITY_TEST 2237 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2238 depends on DEBUG_KERNEL 2239 depends on KPROBES 2240 depends on KUNIT 2241 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2242 default KUNIT_ALL_TESTS 2243 help 2244 This option provides for testing basic kprobes functionality on 2245 boot. Samples of kprobe and kretprobe are inserted and 2246 verified for functionality. 2247 2248 Say N if you are unsure. 2249 2250config FPROBE_SANITY_TEST 2251 bool "Self test for fprobe" 2252 depends on DEBUG_KERNEL 2253 depends on FPROBE 2254 depends on KUNIT=y 2255 help 2256 This option will enable testing the fprobe when the system boot. 2257 A series of tests are made to verify that the fprobe is functioning 2258 properly. 2259 2260 Say N if you are unsure. 2261 2262config BACKTRACE_SELF_TEST 2263 tristate "Self test for the backtrace code" 2264 depends on DEBUG_KERNEL 2265 help 2266 This option provides a kernel module that can be used to test 2267 the kernel stack backtrace code. This option is not useful 2268 for distributions or general kernels, but only for kernel 2269 developers working on architecture code. 2270 2271 Note that if you want to also test saved backtraces, you will 2272 have to enable STACKTRACE as well. 2273 2274 Say N if you are unsure. 2275 2276config TEST_REF_TRACKER 2277 tristate "Self test for reference tracker" 2278 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2279 select REF_TRACKER 2280 help 2281 This option provides a kernel module performing tests 2282 using reference tracker infrastructure. 2283 2284 Say N if you are unsure. 2285 2286config RBTREE_TEST 2287 tristate "Red-Black tree test" 2288 depends on DEBUG_KERNEL 2289 help 2290 A benchmark measuring the performance of the rbtree library. 2291 Also includes rbtree invariant checks. 2292 2293config REED_SOLOMON_TEST 2294 tristate "Reed-Solomon library test" 2295 depends on DEBUG_KERNEL || m 2296 select REED_SOLOMON 2297 select REED_SOLOMON_ENC16 2298 select REED_SOLOMON_DEC16 2299 help 2300 This option enables the self-test function of rslib at boot, 2301 or at module load time. 2302 2303 If unsure, say N. 2304 2305config INTERVAL_TREE_TEST 2306 tristate "Interval tree test" 2307 depends on DEBUG_KERNEL 2308 select INTERVAL_TREE 2309 help 2310 A benchmark measuring the performance of the interval tree library 2311 2312config PERCPU_TEST 2313 tristate "Per cpu operations test" 2314 depends on m && DEBUG_KERNEL 2315 help 2316 Enable this option to build test module which validates per-cpu 2317 operations. 2318 2319 If unsure, say N. 2320 2321config ATOMIC64_SELFTEST 2322 tristate "Perform an atomic64_t self-test" 2323 help 2324 Enable this option to test the atomic64_t functions at boot or 2325 at module load time. 2326 2327 If unsure, say N. 2328 2329config ASYNC_RAID6_TEST 2330 tristate "Self test for hardware accelerated raid6 recovery" 2331 depends on ASYNC_RAID6_RECOV 2332 select ASYNC_MEMCPY 2333 help 2334 This is a one-shot self test that permutes through the 2335 recovery of all the possible two disk failure scenarios for a 2336 N-disk array. Recovery is performed with the asynchronous 2337 raid6 recovery routines, and will optionally use an offload 2338 engine if one is available. 2339 2340 If unsure, say N. 2341 2342config TEST_HEXDUMP 2343 tristate "Test functions located in the hexdump module at runtime" 2344 2345config STRING_SELFTEST 2346 tristate "Test string functions at runtime" 2347 2348config TEST_STRING_HELPERS 2349 tristate "Test functions located in the string_helpers module at runtime" 2350 2351config TEST_KSTRTOX 2352 tristate "Test kstrto*() family of functions at runtime" 2353 2354config TEST_PRINTF 2355 tristate "Test printf() family of functions at runtime" 2356 2357config TEST_SCANF 2358 tristate "Test scanf() family of functions at runtime" 2359 2360config TEST_BITMAP 2361 tristate "Test bitmap_*() family of functions at runtime" 2362 help 2363 Enable this option to test the bitmap functions at boot. 2364 2365 If unsure, say N. 2366 2367config TEST_UUID 2368 tristate "Test functions located in the uuid module at runtime" 2369 2370config TEST_XARRAY 2371 tristate "Test the XArray code at runtime" 2372 2373config TEST_MAPLE_TREE 2374 tristate "Test the Maple Tree code at runtime or module load" 2375 help 2376 Enable this option to test the maple tree code functions at boot, or 2377 when the module is loaded. Enable "Debug Maple Trees" will enable 2378 more verbose output on failures. 2379 2380 If unsure, say N. 2381 2382config TEST_RHASHTABLE 2383 tristate "Perform selftest on resizable hash table" 2384 help 2385 Enable this option to test the rhashtable functions at boot. 2386 2387 If unsure, say N. 2388 2389config TEST_IDA 2390 tristate "Perform selftest on IDA functions" 2391 2392config TEST_PARMAN 2393 tristate "Perform selftest on priority array manager" 2394 depends on PARMAN 2395 help 2396 Enable this option to test priority array manager on boot 2397 (or module load). 2398 2399 If unsure, say N. 2400 2401config TEST_IRQ_TIMINGS 2402 bool "IRQ timings selftest" 2403 depends on IRQ_TIMINGS 2404 help 2405 Enable this option to test the irq timings code on boot. 2406 2407 If unsure, say N. 2408 2409config TEST_LKM 2410 tristate "Test module loading with 'hello world' module" 2411 depends on m 2412 help 2413 This builds the "test_module" module that emits "Hello, world" 2414 on printk when loaded. It is designed to be used for basic 2415 evaluation of the module loading subsystem (for example when 2416 validating module verification). It lacks any extra dependencies, 2417 and will not normally be loaded by the system unless explicitly 2418 requested by name. 2419 2420 If unsure, say N. 2421 2422config TEST_BITOPS 2423 tristate "Test module for compilation of bitops operations" 2424 depends on m 2425 help 2426 This builds the "test_bitops" module that is much like the 2427 TEST_LKM module except that it does a basic exercise of the 2428 set/clear_bit macros and get_count_order/long to make sure there are 2429 no compiler warnings from C=1 sparse checker or -Wextra 2430 compilations. It has no dependencies and doesn't run or load unless 2431 explicitly requested by name. for example: modprobe test_bitops. 2432 2433 If unsure, say N. 2434 2435config TEST_VMALLOC 2436 tristate "Test module for stress/performance analysis of vmalloc allocator" 2437 default n 2438 depends on MMU 2439 depends on m 2440 help 2441 This builds the "test_vmalloc" module that should be used for 2442 stress and performance analysis. So, any new change for vmalloc 2443 subsystem can be evaluated from performance and stability point 2444 of view. 2445 2446 If unsure, say N. 2447 2448config TEST_USER_COPY 2449 tristate "Test user/kernel boundary protections" 2450 depends on m 2451 help 2452 This builds the "test_user_copy" module that runs sanity checks 2453 on the copy_to/from_user infrastructure, making sure basic 2454 user/kernel boundary testing is working. If it fails to load, 2455 a regression has been detected in the user/kernel memory boundary 2456 protections. 2457 2458 If unsure, say N. 2459 2460config TEST_BPF 2461 tristate "Test BPF filter functionality" 2462 depends on m && NET 2463 help 2464 This builds the "test_bpf" module that runs various test vectors 2465 against the BPF interpreter or BPF JIT compiler depending on the 2466 current setting. This is in particular useful for BPF JIT compiler 2467 development, but also to run regression tests against changes in 2468 the interpreter code. It also enables test stubs for eBPF maps and 2469 verifier used by user space verifier testsuite. 2470 2471 If unsure, say N. 2472 2473config TEST_BLACKHOLE_DEV 2474 tristate "Test blackhole netdev functionality" 2475 depends on m && NET 2476 help 2477 This builds the "test_blackhole_dev" module that validates the 2478 data path through this blackhole netdev. 2479 2480 If unsure, say N. 2481 2482config FIND_BIT_BENCHMARK 2483 tristate "Test find_bit functions" 2484 help 2485 This builds the "test_find_bit" module that measure find_*_bit() 2486 functions performance. 2487 2488 If unsure, say N. 2489 2490config TEST_FIRMWARE 2491 tristate "Test firmware loading via userspace interface" 2492 depends on FW_LOADER 2493 help 2494 This builds the "test_firmware" module that creates a userspace 2495 interface for testing firmware loading. This can be used to 2496 control the triggering of firmware loading without needing an 2497 actual firmware-using device. The contents can be rechecked by 2498 userspace. 2499 2500 If unsure, say N. 2501 2502config TEST_SYSCTL 2503 tristate "sysctl test driver" 2504 depends on PROC_SYSCTL 2505 help 2506 This builds the "test_sysctl" module. This driver enables to test the 2507 proc sysctl interfaces available to drivers safely without affecting 2508 production knobs which might alter system functionality. 2509 2510 If unsure, say N. 2511 2512config BITFIELD_KUNIT 2513 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2514 depends on KUNIT 2515 default KUNIT_ALL_TESTS 2516 help 2517 Enable this option to test the bitfield functions at boot. 2518 2519 KUnit tests run during boot and output the results to the debug log 2520 in TAP format (http://testanything.org/). Only useful for kernel devs 2521 running the KUnit test harness, and not intended for inclusion into a 2522 production build. 2523 2524 For more information on KUnit and unit tests in general please refer 2525 to the KUnit documentation in Documentation/dev-tools/kunit/. 2526 2527 If unsure, say N. 2528 2529config CHECKSUM_KUNIT 2530 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS 2531 depends on KUNIT 2532 default KUNIT_ALL_TESTS 2533 help 2534 Enable this option to test the checksum functions at boot. 2535 2536 KUnit tests run during boot and output the results to the debug log 2537 in TAP format (http://testanything.org/). Only useful for kernel devs 2538 running the KUnit test harness, and not intended for inclusion into a 2539 production build. 2540 2541 For more information on KUnit and unit tests in general please refer 2542 to the KUnit documentation in Documentation/dev-tools/kunit/. 2543 2544 If unsure, say N. 2545 2546config HASH_KUNIT_TEST 2547 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2548 depends on KUNIT 2549 default KUNIT_ALL_TESTS 2550 help 2551 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2552 integer (<linux/hash.h>) hash functions on boot. 2553 2554 KUnit tests run during boot and output the results to the debug log 2555 in TAP format (https://testanything.org/). Only useful for kernel devs 2556 running the KUnit test harness, and not intended for inclusion into a 2557 production build. 2558 2559 For more information on KUnit and unit tests in general please refer 2560 to the KUnit documentation in Documentation/dev-tools/kunit/. 2561 2562 This is intended to help people writing architecture-specific 2563 optimized versions. If unsure, say N. 2564 2565config RESOURCE_KUNIT_TEST 2566 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2567 depends on KUNIT 2568 default KUNIT_ALL_TESTS 2569 help 2570 This builds the resource API unit test. 2571 Tests the logic of API provided by resource.c and ioport.h. 2572 For more information on KUnit and unit tests in general please refer 2573 to the KUnit documentation in Documentation/dev-tools/kunit/. 2574 2575 If unsure, say N. 2576 2577config SYSCTL_KUNIT_TEST 2578 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2579 depends on KUNIT 2580 default KUNIT_ALL_TESTS 2581 help 2582 This builds the proc sysctl unit test, which runs on boot. 2583 Tests the API contract and implementation correctness of sysctl. 2584 For more information on KUnit and unit tests in general please refer 2585 to the KUnit documentation in Documentation/dev-tools/kunit/. 2586 2587 If unsure, say N. 2588 2589config LIST_KUNIT_TEST 2590 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2591 depends on KUNIT 2592 default KUNIT_ALL_TESTS 2593 help 2594 This builds the linked list KUnit test suite. 2595 It tests that the API and basic functionality of the list_head type 2596 and associated macros. 2597 2598 KUnit tests run during boot and output the results to the debug log 2599 in TAP format (https://testanything.org/). Only useful for kernel devs 2600 running the KUnit test harness, and not intended for inclusion into a 2601 production build. 2602 2603 For more information on KUnit and unit tests in general please refer 2604 to the KUnit documentation in Documentation/dev-tools/kunit/. 2605 2606 If unsure, say N. 2607 2608config HASHTABLE_KUNIT_TEST 2609 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS 2610 depends on KUNIT 2611 default KUNIT_ALL_TESTS 2612 help 2613 This builds the hashtable KUnit test suite. 2614 It tests the basic functionality of the API defined in 2615 include/linux/hashtable.h. For more information on KUnit and 2616 unit tests in general please refer to the KUnit documentation 2617 in Documentation/dev-tools/kunit/. 2618 2619 If unsure, say N. 2620 2621config LINEAR_RANGES_TEST 2622 tristate "KUnit test for linear_ranges" 2623 depends on KUNIT 2624 select LINEAR_RANGES 2625 help 2626 This builds the linear_ranges unit test, which runs on boot. 2627 Tests the linear_ranges logic correctness. 2628 For more information on KUnit and unit tests in general please refer 2629 to the KUnit documentation in Documentation/dev-tools/kunit/. 2630 2631 If unsure, say N. 2632 2633config CMDLINE_KUNIT_TEST 2634 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2635 depends on KUNIT 2636 default KUNIT_ALL_TESTS 2637 help 2638 This builds the cmdline API unit test. 2639 Tests the logic of API provided by cmdline.c. 2640 For more information on KUnit and unit tests in general please refer 2641 to the KUnit documentation in Documentation/dev-tools/kunit/. 2642 2643 If unsure, say N. 2644 2645config BITS_TEST 2646 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2647 depends on KUNIT 2648 default KUNIT_ALL_TESTS 2649 help 2650 This builds the bits unit test. 2651 Tests the logic of macros defined in bits.h. 2652 For more information on KUnit and unit tests in general please refer 2653 to the KUnit documentation in Documentation/dev-tools/kunit/. 2654 2655 If unsure, say N. 2656 2657config SLUB_KUNIT_TEST 2658 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2659 depends on SLUB_DEBUG && KUNIT 2660 default KUNIT_ALL_TESTS 2661 help 2662 This builds SLUB allocator unit test. 2663 Tests SLUB cache debugging functionality. 2664 For more information on KUnit and unit tests in general please refer 2665 to the KUnit documentation in Documentation/dev-tools/kunit/. 2666 2667 If unsure, say N. 2668 2669config RATIONAL_KUNIT_TEST 2670 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2671 depends on KUNIT && RATIONAL 2672 default KUNIT_ALL_TESTS 2673 help 2674 This builds the rational math unit test. 2675 For more information on KUnit and unit tests in general please refer 2676 to the KUnit documentation in Documentation/dev-tools/kunit/. 2677 2678 If unsure, say N. 2679 2680config MEMCPY_KUNIT_TEST 2681 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2682 depends on KUNIT 2683 default KUNIT_ALL_TESTS 2684 help 2685 Builds unit tests for memcpy(), memmove(), and memset() functions. 2686 For more information on KUnit and unit tests in general please refer 2687 to the KUnit documentation in Documentation/dev-tools/kunit/. 2688 2689 If unsure, say N. 2690 2691config MEMCPY_SLOW_KUNIT_TEST 2692 bool "Include exhaustive memcpy tests" 2693 depends on MEMCPY_KUNIT_TEST 2694 default y 2695 help 2696 Some memcpy tests are quite exhaustive in checking for overlaps 2697 and bit ranges. These can be very slow, so they are split out 2698 as a separate config, in case they need to be disabled. 2699 2700 Note this config option will be replaced by the use of KUnit test 2701 attributes. 2702 2703config IS_SIGNED_TYPE_KUNIT_TEST 2704 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2705 depends on KUNIT 2706 default KUNIT_ALL_TESTS 2707 help 2708 Builds unit tests for the is_signed_type() macro. 2709 2710 For more information on KUnit and unit tests in general please refer 2711 to the KUnit documentation in Documentation/dev-tools/kunit/. 2712 2713 If unsure, say N. 2714 2715config OVERFLOW_KUNIT_TEST 2716 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2717 depends on KUNIT 2718 default KUNIT_ALL_TESTS 2719 help 2720 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2721 related functions. 2722 2723 For more information on KUnit and unit tests in general please refer 2724 to the KUnit documentation in Documentation/dev-tools/kunit/. 2725 2726 If unsure, say N. 2727 2728config STACKINIT_KUNIT_TEST 2729 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2730 depends on KUNIT 2731 default KUNIT_ALL_TESTS 2732 help 2733 Test if the kernel is zero-initializing stack variables and 2734 padding. Coverage is controlled by compiler flags, 2735 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2736 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2737 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2738 2739config FORTIFY_KUNIT_TEST 2740 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2741 depends on KUNIT && FORTIFY_SOURCE 2742 default KUNIT_ALL_TESTS 2743 help 2744 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2745 by the str*() and mem*() family of functions. For testing runtime 2746 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2747 2748config HW_BREAKPOINT_KUNIT_TEST 2749 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2750 depends on HAVE_HW_BREAKPOINT 2751 depends on KUNIT=y 2752 default KUNIT_ALL_TESTS 2753 help 2754 Tests for hw_breakpoint constraints accounting. 2755 2756 If unsure, say N. 2757 2758config STRCAT_KUNIT_TEST 2759 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS 2760 depends on KUNIT 2761 default KUNIT_ALL_TESTS 2762 2763config STRSCPY_KUNIT_TEST 2764 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2765 depends on KUNIT 2766 default KUNIT_ALL_TESTS 2767 2768config SIPHASH_KUNIT_TEST 2769 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2770 depends on KUNIT 2771 default KUNIT_ALL_TESTS 2772 help 2773 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2774 functions on boot (or module load). 2775 2776 This is intended to help people writing architecture-specific 2777 optimized versions. If unsure, say N. 2778 2779config TEST_UDELAY 2780 tristate "udelay test driver" 2781 help 2782 This builds the "udelay_test" module that helps to make sure 2783 that udelay() is working properly. 2784 2785 If unsure, say N. 2786 2787config TEST_STATIC_KEYS 2788 tristate "Test static keys" 2789 depends on m 2790 help 2791 Test the static key interfaces. 2792 2793 If unsure, say N. 2794 2795config TEST_DYNAMIC_DEBUG 2796 tristate "Test DYNAMIC_DEBUG" 2797 depends on DYNAMIC_DEBUG 2798 help 2799 This module registers a tracer callback to count enabled 2800 pr_debugs in a 'do_debugging' function, then alters their 2801 enablements, calls the function, and compares counts. 2802 2803 If unsure, say N. 2804 2805config TEST_KMOD 2806 tristate "kmod stress tester" 2807 depends on m 2808 depends on NETDEVICES && NET_CORE && INET # for TUN 2809 depends on BLOCK 2810 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2811 select TEST_LKM 2812 select XFS_FS 2813 select TUN 2814 select BTRFS_FS 2815 help 2816 Test the kernel's module loading mechanism: kmod. kmod implements 2817 support to load modules using the Linux kernel's usermode helper. 2818 This test provides a series of tests against kmod. 2819 2820 Although technically you can either build test_kmod as a module or 2821 into the kernel we disallow building it into the kernel since 2822 it stress tests request_module() and this will very likely cause 2823 some issues by taking over precious threads available from other 2824 module load requests, ultimately this could be fatal. 2825 2826 To run tests run: 2827 2828 tools/testing/selftests/kmod/kmod.sh --help 2829 2830 If unsure, say N. 2831 2832config TEST_DEBUG_VIRTUAL 2833 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2834 depends on DEBUG_VIRTUAL 2835 help 2836 Test the kernel's ability to detect incorrect calls to 2837 virt_to_phys() done against the non-linear part of the 2838 kernel's virtual address map. 2839 2840 If unsure, say N. 2841 2842config TEST_MEMCAT_P 2843 tristate "Test memcat_p() helper function" 2844 help 2845 Test the memcat_p() helper for correctly merging two 2846 pointer arrays together. 2847 2848 If unsure, say N. 2849 2850config TEST_LIVEPATCH 2851 tristate "Test livepatching" 2852 default n 2853 depends on DYNAMIC_DEBUG 2854 depends on LIVEPATCH 2855 depends on m 2856 help 2857 Test kernel livepatching features for correctness. The tests will 2858 load test modules that will be livepatched in various scenarios. 2859 2860 To run all the livepatching tests: 2861 2862 make -C tools/testing/selftests TARGETS=livepatch run_tests 2863 2864 Alternatively, individual tests may be invoked: 2865 2866 tools/testing/selftests/livepatch/test-callbacks.sh 2867 tools/testing/selftests/livepatch/test-livepatch.sh 2868 tools/testing/selftests/livepatch/test-shadow-vars.sh 2869 2870 If unsure, say N. 2871 2872config TEST_OBJAGG 2873 tristate "Perform selftest on object aggreration manager" 2874 default n 2875 depends on OBJAGG 2876 help 2877 Enable this option to test object aggregation manager on boot 2878 (or module load). 2879 2880config TEST_MEMINIT 2881 tristate "Test heap/page initialization" 2882 help 2883 Test if the kernel is zero-initializing heap and page allocations. 2884 This can be useful to test init_on_alloc and init_on_free features. 2885 2886 If unsure, say N. 2887 2888config TEST_HMM 2889 tristate "Test HMM (Heterogeneous Memory Management)" 2890 depends on TRANSPARENT_HUGEPAGE 2891 depends on DEVICE_PRIVATE 2892 select HMM_MIRROR 2893 select MMU_NOTIFIER 2894 help 2895 This is a pseudo device driver solely for testing HMM. 2896 Say M here if you want to build the HMM test module. 2897 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2898 2899 If unsure, say N. 2900 2901config TEST_FREE_PAGES 2902 tristate "Test freeing pages" 2903 help 2904 Test that a memory leak does not occur due to a race between 2905 freeing a block of pages and a speculative page reference. 2906 Loading this module is safe if your kernel has the bug fixed. 2907 If the bug is not fixed, it will leak gigabytes of memory and 2908 probably OOM your system. 2909 2910config TEST_FPU 2911 tristate "Test floating point operations in kernel space" 2912 depends on X86 && !KCOV_INSTRUMENT_ALL 2913 help 2914 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2915 which will trigger a sequence of floating point operations. This is used 2916 for self-testing floating point control register setting in 2917 kernel_fpu_begin(). 2918 2919 If unsure, say N. 2920 2921config TEST_CLOCKSOURCE_WATCHDOG 2922 tristate "Test clocksource watchdog in kernel space" 2923 depends on CLOCKSOURCE_WATCHDOG 2924 help 2925 Enable this option to create a kernel module that will trigger 2926 a test of the clocksource watchdog. This module may be loaded 2927 via modprobe or insmod in which case it will run upon being 2928 loaded, or it may be built in, in which case it will run 2929 shortly after boot. 2930 2931 If unsure, say N. 2932 2933endif # RUNTIME_TESTING_MENU 2934 2935config ARCH_USE_MEMTEST 2936 bool 2937 help 2938 An architecture should select this when it uses early_memtest() 2939 during boot process. 2940 2941config MEMTEST 2942 bool "Memtest" 2943 depends on ARCH_USE_MEMTEST 2944 help 2945 This option adds a kernel parameter 'memtest', which allows memtest 2946 to be set and executed. 2947 memtest=0, mean disabled; -- default 2948 memtest=1, mean do 1 test pattern; 2949 ... 2950 memtest=17, mean do 17 test patterns. 2951 If you are unsure how to answer this question, answer N. 2952 2953 2954 2955config HYPERV_TESTING 2956 bool "Microsoft Hyper-V driver testing" 2957 default n 2958 depends on HYPERV && DEBUG_FS 2959 help 2960 Select this option to enable Hyper-V vmbus testing. 2961 2962endmenu # "Kernel Testing and Coverage" 2963 2964menu "Rust hacking" 2965 2966config RUST_DEBUG_ASSERTIONS 2967 bool "Debug assertions" 2968 depends on RUST 2969 help 2970 Enables rustc's `-Cdebug-assertions` codegen option. 2971 2972 This flag lets you turn `cfg(debug_assertions)` conditional 2973 compilation on or off. This can be used to enable extra debugging 2974 code in development but not in production. For example, it controls 2975 the behavior of the standard library's `debug_assert!` macro. 2976 2977 Note that this will apply to all Rust code, including `core`. 2978 2979 If unsure, say N. 2980 2981config RUST_OVERFLOW_CHECKS 2982 bool "Overflow checks" 2983 default y 2984 depends on RUST 2985 help 2986 Enables rustc's `-Coverflow-checks` codegen option. 2987 2988 This flag allows you to control the behavior of runtime integer 2989 overflow. When overflow-checks are enabled, a Rust panic will occur 2990 on overflow. 2991 2992 Note that this will apply to all Rust code, including `core`. 2993 2994 If unsure, say Y. 2995 2996config RUST_BUILD_ASSERT_ALLOW 2997 bool "Allow unoptimized build-time assertions" 2998 depends on RUST 2999 help 3000 Controls how are `build_error!` and `build_assert!` handled during build. 3001 3002 If calls to them exist in the binary, it may indicate a violated invariant 3003 or that the optimizer failed to verify the invariant during compilation. 3004 3005 This should not happen, thus by default the build is aborted. However, 3006 as an escape hatch, you can choose Y here to ignore them during build 3007 and let the check be carried at runtime (with `panic!` being called if 3008 the check fails). 3009 3010 If unsure, say N. 3011 3012config RUST_KERNEL_DOCTESTS 3013 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS 3014 depends on RUST && KUNIT=y 3015 default KUNIT_ALL_TESTS 3016 help 3017 This builds the documentation tests of the `kernel` crate 3018 as KUnit tests. 3019 3020 For more information on KUnit and unit tests in general, 3021 please refer to the KUnit documentation in Documentation/dev-tools/kunit/. 3022 3023 If unsure, say N. 3024 3025endmenu # "Rust" 3026 3027endmenu # Kernel hacking 3028