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