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) 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 HAVE_DEBUG_KMEMLEAK 756 bool 757 758config DEBUG_KMEMLEAK 759 bool "Kernel memory leak detector" 760 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 761 select DEBUG_FS 762 select STACKTRACE if STACKTRACE_SUPPORT 763 select KALLSYMS 764 select CRC32 765 select STACKDEPOT 766 select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF 767 help 768 Say Y here if you want to enable the memory leak 769 detector. The memory allocation/freeing is traced in a way 770 similar to the Boehm's conservative garbage collector, the 771 difference being that the orphan objects are not freed but 772 only shown in /sys/kernel/debug/kmemleak. Enabling this 773 feature will introduce an overhead to memory 774 allocations. See Documentation/dev-tools/kmemleak.rst for more 775 details. 776 777 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 778 of finding leaks due to the slab objects poisoning. 779 780 In order to access the kmemleak file, debugfs needs to be 781 mounted (usually at /sys/kernel/debug). 782 783config DEBUG_KMEMLEAK_MEM_POOL_SIZE 784 int "Kmemleak memory pool size" 785 depends on DEBUG_KMEMLEAK 786 range 200 1000000 787 default 16000 788 help 789 Kmemleak must track all the memory allocations to avoid 790 reporting false positives. Since memory may be allocated or 791 freed before kmemleak is fully initialised, use a static pool 792 of metadata objects to track such callbacks. After kmemleak is 793 fully initialised, this memory pool acts as an emergency one 794 if slab allocations fail. 795 796config DEBUG_KMEMLEAK_TEST 797 tristate "Simple test for the kernel memory leak detector" 798 depends on DEBUG_KMEMLEAK && m 799 help 800 This option enables a module that explicitly leaks memory. 801 802 If unsure, say N. 803 804config DEBUG_KMEMLEAK_DEFAULT_OFF 805 bool "Default kmemleak to off" 806 depends on DEBUG_KMEMLEAK 807 help 808 Say Y here to disable kmemleak by default. It can then be enabled 809 on the command line via kmemleak=on. 810 811config DEBUG_KMEMLEAK_AUTO_SCAN 812 bool "Enable kmemleak auto scan thread on boot up" 813 default y 814 depends on DEBUG_KMEMLEAK 815 help 816 Depending on the cpu, kmemleak scan may be cpu intensive and can 817 stall user tasks at times. This option enables/disables automatic 818 kmemleak scan at boot up. 819 820 Say N here to disable kmemleak auto scan thread to stop automatic 821 scanning. Disabling this option disables automatic reporting of 822 memory leaks. 823 824 If unsure, say Y. 825 826config DEBUG_STACK_USAGE 827 bool "Stack utilization instrumentation" 828 depends on DEBUG_KERNEL && !IA64 829 help 830 Enables the display of the minimum amount of free stack which each 831 task has ever had available in the sysrq-T and sysrq-P debug output. 832 833 This option will slow down process creation somewhat. 834 835config SCHED_STACK_END_CHECK 836 bool "Detect stack corruption on calls to schedule()" 837 depends on DEBUG_KERNEL 838 default n 839 help 840 This option checks for a stack overrun on calls to schedule(). 841 If the stack end location is found to be over written always panic as 842 the content of the corrupted region can no longer be trusted. 843 This is to ensure no erroneous behaviour occurs which could result in 844 data corruption or a sporadic crash at a later stage once the region 845 is examined. The runtime overhead introduced is minimal. 846 847config ARCH_HAS_DEBUG_VM_PGTABLE 848 bool 849 help 850 An architecture should select this when it can successfully 851 build and run DEBUG_VM_PGTABLE. 852 853config DEBUG_VM_IRQSOFF 854 def_bool DEBUG_VM && !PREEMPT_RT 855 856config DEBUG_VM 857 bool "Debug VM" 858 depends on DEBUG_KERNEL 859 help 860 Enable this to turn on extended checks in the virtual-memory system 861 that may impact performance. 862 863 If unsure, say N. 864 865config DEBUG_VM_MAPLE_TREE 866 bool "Debug VM maple trees" 867 depends on DEBUG_VM 868 select DEBUG_MAPLE_TREE 869 help 870 Enable VM maple tree debugging information and extra validations. 871 872 If unsure, say N. 873 874config DEBUG_VM_RB 875 bool "Debug VM red-black trees" 876 depends on DEBUG_VM 877 help 878 Enable VM red-black tree debugging information and extra validations. 879 880 If unsure, say N. 881 882config DEBUG_VM_PGFLAGS 883 bool "Debug page-flags operations" 884 depends on DEBUG_VM 885 help 886 Enables extra validation on page flags operations. 887 888 If unsure, say N. 889 890config DEBUG_VM_PGTABLE 891 bool "Debug arch page table for semantics compliance" 892 depends on MMU 893 depends on ARCH_HAS_DEBUG_VM_PGTABLE 894 default y if DEBUG_VM 895 help 896 This option provides a debug method which can be used to test 897 architecture page table helper functions on various platforms in 898 verifying if they comply with expected generic MM semantics. This 899 will help architecture code in making sure that any changes or 900 new additions of these helpers still conform to expected 901 semantics of the generic MM. Platforms will have to opt in for 902 this through ARCH_HAS_DEBUG_VM_PGTABLE. 903 904 If unsure, say N. 905 906config ARCH_HAS_DEBUG_VIRTUAL 907 bool 908 909config DEBUG_VIRTUAL 910 bool "Debug VM translations" 911 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 912 help 913 Enable some costly sanity checks in virtual to page code. This can 914 catch mistakes with virt_to_page() and friends. 915 916 If unsure, say N. 917 918config DEBUG_NOMMU_REGIONS 919 bool "Debug the global anon/private NOMMU mapping region tree" 920 depends on DEBUG_KERNEL && !MMU 921 help 922 This option causes the global tree of anonymous and private mapping 923 regions to be regularly checked for invalid topology. 924 925config DEBUG_MEMORY_INIT 926 bool "Debug memory initialisation" if EXPERT 927 default !EXPERT 928 help 929 Enable this for additional checks during memory initialisation. 930 The sanity checks verify aspects of the VM such as the memory model 931 and other information provided by the architecture. Verbose 932 information will be printed at KERN_DEBUG loglevel depending 933 on the mminit_loglevel= command-line option. 934 935 If unsure, say Y 936 937config MEMORY_NOTIFIER_ERROR_INJECT 938 tristate "Memory hotplug notifier error injection module" 939 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 940 help 941 This option provides the ability to inject artificial errors to 942 memory hotplug notifier chain callbacks. It is controlled through 943 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 944 945 If the notifier call chain should be failed with some events 946 notified, write the error code to "actions/<notifier event>/error". 947 948 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 949 950 # cd /sys/kernel/debug/notifier-error-inject/memory 951 # echo -12 > actions/MEM_GOING_OFFLINE/error 952 # echo offline > /sys/devices/system/memory/memoryXXX/state 953 bash: echo: write error: Cannot allocate memory 954 955 To compile this code as a module, choose M here: the module will 956 be called memory-notifier-error-inject. 957 958 If unsure, say N. 959 960config DEBUG_PER_CPU_MAPS 961 bool "Debug access to per_cpu maps" 962 depends on DEBUG_KERNEL 963 depends on SMP 964 help 965 Say Y to verify that the per_cpu map being accessed has 966 been set up. This adds a fair amount of code to kernel memory 967 and decreases performance. 968 969 Say N if unsure. 970 971config DEBUG_KMAP_LOCAL 972 bool "Debug kmap_local temporary mappings" 973 depends on DEBUG_KERNEL && KMAP_LOCAL 974 help 975 This option enables additional error checking for the kmap_local 976 infrastructure. Disable for production use. 977 978config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 979 bool 980 981config DEBUG_KMAP_LOCAL_FORCE_MAP 982 bool "Enforce kmap_local temporary mappings" 983 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 984 select KMAP_LOCAL 985 select DEBUG_KMAP_LOCAL 986 help 987 This option enforces temporary mappings through the kmap_local 988 mechanism for non-highmem pages and on non-highmem systems. 989 Disable this for production systems! 990 991config DEBUG_HIGHMEM 992 bool "Highmem debugging" 993 depends on DEBUG_KERNEL && HIGHMEM 994 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 995 select DEBUG_KMAP_LOCAL 996 help 997 This option enables additional error checking for high memory 998 systems. Disable for production systems. 999 1000config HAVE_DEBUG_STACKOVERFLOW 1001 bool 1002 1003config DEBUG_STACKOVERFLOW 1004 bool "Check for stack overflows" 1005 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 1006 help 1007 Say Y here if you want to check for overflows of kernel, IRQ 1008 and exception stacks (if your architecture uses them). This 1009 option will show detailed messages if free stack space drops 1010 below a certain limit. 1011 1012 These kinds of bugs usually occur when call-chains in the 1013 kernel get too deep, especially when interrupts are 1014 involved. 1015 1016 Use this in cases where you see apparently random memory 1017 corruption, especially if it appears in 'struct thread_info' 1018 1019 If in doubt, say "N". 1020 1021source "lib/Kconfig.kasan" 1022source "lib/Kconfig.kfence" 1023source "lib/Kconfig.kmsan" 1024 1025endmenu # "Memory Debugging" 1026 1027config DEBUG_SHIRQ 1028 bool "Debug shared IRQ handlers" 1029 depends on DEBUG_KERNEL 1030 help 1031 Enable this to generate a spurious interrupt just before a shared 1032 interrupt handler is deregistered (generating one when registering 1033 is currently disabled). Drivers need to handle this correctly. Some 1034 don't and need to be caught. 1035 1036menu "Debug Oops, Lockups and Hangs" 1037 1038config PANIC_ON_OOPS 1039 bool "Panic on Oops" 1040 help 1041 Say Y here to enable the kernel to panic when it oopses. This 1042 has the same effect as setting oops=panic on the kernel command 1043 line. 1044 1045 This feature is useful to ensure that the kernel does not do 1046 anything erroneous after an oops which could result in data 1047 corruption or other issues. 1048 1049 Say N if unsure. 1050 1051config PANIC_ON_OOPS_VALUE 1052 int 1053 range 0 1 1054 default 0 if !PANIC_ON_OOPS 1055 default 1 if PANIC_ON_OOPS 1056 1057config PANIC_TIMEOUT 1058 int "panic timeout" 1059 default 0 1060 help 1061 Set the timeout value (in seconds) until a reboot occurs when 1062 the kernel panics. If n = 0, then we wait forever. A timeout 1063 value n > 0 will wait n seconds before rebooting, while a timeout 1064 value n < 0 will reboot immediately. 1065 1066config LOCKUP_DETECTOR 1067 bool 1068 1069config SOFTLOCKUP_DETECTOR 1070 bool "Detect Soft Lockups" 1071 depends on DEBUG_KERNEL && !S390 1072 select LOCKUP_DETECTOR 1073 help 1074 Say Y here to enable the kernel to act as a watchdog to detect 1075 soft lockups. 1076 1077 Softlockups are bugs that cause the kernel to loop in kernel 1078 mode for more than 20 seconds, without giving other tasks a 1079 chance to run. The current stack trace is displayed upon 1080 detection and the system will stay locked up. 1081 1082config BOOTPARAM_SOFTLOCKUP_PANIC 1083 bool "Panic (Reboot) On Soft Lockups" 1084 depends on SOFTLOCKUP_DETECTOR 1085 help 1086 Say Y here to enable the kernel to panic on "soft lockups", 1087 which are bugs that cause the kernel to loop in kernel 1088 mode for more than 20 seconds (configurable using the watchdog_thresh 1089 sysctl), without giving other tasks a chance to run. 1090 1091 The panic can be used in combination with panic_timeout, 1092 to cause the system to reboot automatically after a 1093 lockup has been detected. This feature is useful for 1094 high-availability systems that have uptime guarantees and 1095 where a lockup must be resolved ASAP. 1096 1097 Say N if unsure. 1098 1099config HARDLOCKUP_DETECTOR_PERF 1100 bool 1101 select SOFTLOCKUP_DETECTOR 1102 1103# 1104# Enables a timestamp based low pass filter to compensate for perf based 1105# hard lockup detection which runs too fast due to turbo modes. 1106# 1107config HARDLOCKUP_CHECK_TIMESTAMP 1108 bool 1109 1110# 1111# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1112# lockup detector rather than the perf based detector. 1113# 1114config HARDLOCKUP_DETECTOR 1115 bool "Detect Hard Lockups" 1116 depends on DEBUG_KERNEL && !S390 1117 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1118 select LOCKUP_DETECTOR 1119 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1120 help 1121 Say Y here to enable the kernel to act as a watchdog to detect 1122 hard lockups. 1123 1124 Hardlockups are bugs that cause the CPU to loop in kernel mode 1125 for more than 10 seconds, without letting other interrupts have a 1126 chance to run. The current stack trace is displayed upon detection 1127 and the system will stay locked up. 1128 1129config BOOTPARAM_HARDLOCKUP_PANIC 1130 bool "Panic (Reboot) On Hard Lockups" 1131 depends on HARDLOCKUP_DETECTOR 1132 help 1133 Say Y here to enable the kernel to panic on "hard lockups", 1134 which are bugs that cause the kernel to loop in kernel 1135 mode with interrupts disabled for more than 10 seconds (configurable 1136 using the watchdog_thresh sysctl). 1137 1138 Say N if unsure. 1139 1140config DETECT_HUNG_TASK 1141 bool "Detect Hung Tasks" 1142 depends on DEBUG_KERNEL 1143 default SOFTLOCKUP_DETECTOR 1144 help 1145 Say Y here to enable the kernel to detect "hung tasks", 1146 which are bugs that cause the task to be stuck in 1147 uninterruptible "D" state indefinitely. 1148 1149 When a hung task is detected, the kernel will print the 1150 current stack trace (which you should report), but the 1151 task will stay in uninterruptible state. If lockdep is 1152 enabled then all held locks will also be reported. This 1153 feature has negligible overhead. 1154 1155config DEFAULT_HUNG_TASK_TIMEOUT 1156 int "Default timeout for hung task detection (in seconds)" 1157 depends on DETECT_HUNG_TASK 1158 default 120 1159 help 1160 This option controls the default timeout (in seconds) used 1161 to determine when a task has become non-responsive and should 1162 be considered hung. 1163 1164 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1165 sysctl or by writing a value to 1166 /proc/sys/kernel/hung_task_timeout_secs. 1167 1168 A timeout of 0 disables the check. The default is two minutes. 1169 Keeping the default should be fine in most cases. 1170 1171config BOOTPARAM_HUNG_TASK_PANIC 1172 bool "Panic (Reboot) On Hung Tasks" 1173 depends on DETECT_HUNG_TASK 1174 help 1175 Say Y here to enable the kernel to panic on "hung tasks", 1176 which are bugs that cause the kernel to leave a task stuck 1177 in uninterruptible "D" state. 1178 1179 The panic can be used in combination with panic_timeout, 1180 to cause the system to reboot automatically after a 1181 hung task has been detected. This feature is useful for 1182 high-availability systems that have uptime guarantees and 1183 where a hung tasks must be resolved ASAP. 1184 1185 Say N if unsure. 1186 1187config WQ_WATCHDOG 1188 bool "Detect Workqueue Stalls" 1189 depends on DEBUG_KERNEL 1190 help 1191 Say Y here to enable stall detection on workqueues. If a 1192 worker pool doesn't make forward progress on a pending work 1193 item for over a given amount of time, 30s by default, a 1194 warning message is printed along with dump of workqueue 1195 state. This can be configured through kernel parameter 1196 "workqueue.watchdog_thresh" and its sysfs counterpart. 1197 1198config TEST_LOCKUP 1199 tristate "Test module to generate lockups" 1200 depends on m 1201 help 1202 This builds the "test_lockup" module that helps to make sure 1203 that watchdogs and lockup detectors are working properly. 1204 1205 Depending on module parameters it could emulate soft or hard 1206 lockup, "hung task", or locking arbitrary lock for a long time. 1207 Also it could generate series of lockups with cooling-down periods. 1208 1209 If unsure, say N. 1210 1211endmenu # "Debug lockups and hangs" 1212 1213menu "Scheduler Debugging" 1214 1215config SCHED_DEBUG 1216 bool "Collect scheduler debugging info" 1217 depends on DEBUG_KERNEL && PROC_FS 1218 default y 1219 help 1220 If you say Y here, the /sys/kernel/debug/sched file will be provided 1221 that can help debug the scheduler. The runtime overhead of this 1222 option is minimal. 1223 1224config SCHED_INFO 1225 bool 1226 default n 1227 1228config SCHEDSTATS 1229 bool "Collect scheduler statistics" 1230 depends on DEBUG_KERNEL && PROC_FS 1231 select SCHED_INFO 1232 help 1233 If you say Y here, additional code will be inserted into the 1234 scheduler and related routines to collect statistics about 1235 scheduler behavior and provide them in /proc/schedstat. These 1236 stats may be useful for both tuning and debugging the scheduler 1237 If you aren't debugging the scheduler or trying to tune a specific 1238 application, you can say N to avoid the very slight overhead 1239 this adds. 1240 1241endmenu 1242 1243config DEBUG_TIMEKEEPING 1244 bool "Enable extra timekeeping sanity checking" 1245 help 1246 This option will enable additional timekeeping sanity checks 1247 which may be helpful when diagnosing issues where timekeeping 1248 problems are suspected. 1249 1250 This may include checks in the timekeeping hotpaths, so this 1251 option may have a (very small) performance impact to some 1252 workloads. 1253 1254 If unsure, say N. 1255 1256config DEBUG_PREEMPT 1257 bool "Debug preemptible kernel" 1258 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1259 default y 1260 help 1261 If you say Y here then the kernel will use a debug variant of the 1262 commonly used smp_processor_id() function and will print warnings 1263 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1264 will detect preemption count underflows. 1265 1266menu "Lock Debugging (spinlocks, mutexes, etc...)" 1267 1268config LOCK_DEBUGGING_SUPPORT 1269 bool 1270 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1271 default y 1272 1273config PROVE_LOCKING 1274 bool "Lock debugging: prove locking correctness" 1275 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1276 select LOCKDEP 1277 select DEBUG_SPINLOCK 1278 select DEBUG_MUTEXES if !PREEMPT_RT 1279 select DEBUG_RT_MUTEXES if RT_MUTEXES 1280 select DEBUG_RWSEMS 1281 select DEBUG_WW_MUTEX_SLOWPATH 1282 select DEBUG_LOCK_ALLOC 1283 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1284 select TRACE_IRQFLAGS 1285 default n 1286 help 1287 This feature enables the kernel to prove that all locking 1288 that occurs in the kernel runtime is mathematically 1289 correct: that under no circumstance could an arbitrary (and 1290 not yet triggered) combination of observed locking 1291 sequences (on an arbitrary number of CPUs, running an 1292 arbitrary number of tasks and interrupt contexts) cause a 1293 deadlock. 1294 1295 In short, this feature enables the kernel to report locking 1296 related deadlocks before they actually occur. 1297 1298 The proof does not depend on how hard and complex a 1299 deadlock scenario would be to trigger: how many 1300 participant CPUs, tasks and irq-contexts would be needed 1301 for it to trigger. The proof also does not depend on 1302 timing: if a race and a resulting deadlock is possible 1303 theoretically (no matter how unlikely the race scenario 1304 is), it will be proven so and will immediately be 1305 reported by the kernel (once the event is observed that 1306 makes the deadlock theoretically possible). 1307 1308 If a deadlock is impossible (i.e. the locking rules, as 1309 observed by the kernel, are mathematically correct), the 1310 kernel reports nothing. 1311 1312 NOTE: this feature can also be enabled for rwlocks, mutexes 1313 and rwsems - in which case all dependencies between these 1314 different locking variants are observed and mapped too, and 1315 the proof of observed correctness is also maintained for an 1316 arbitrary combination of these separate locking variants. 1317 1318 For more details, see Documentation/locking/lockdep-design.rst. 1319 1320config PROVE_RAW_LOCK_NESTING 1321 bool "Enable raw_spinlock - spinlock nesting checks" 1322 depends on PROVE_LOCKING 1323 default n 1324 help 1325 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1326 that the lock nesting rules for PREEMPT_RT enabled kernels are 1327 not violated. 1328 1329 NOTE: There are known nesting problems. So if you enable this 1330 option expect lockdep splats until these problems have been fully 1331 addressed which is work in progress. This config switch allows to 1332 identify and analyze these problems. It will be removed and the 1333 check permanently enabled once the main issues have been fixed. 1334 1335 If unsure, select N. 1336 1337config LOCK_STAT 1338 bool "Lock usage statistics" 1339 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1340 select LOCKDEP 1341 select DEBUG_SPINLOCK 1342 select DEBUG_MUTEXES if !PREEMPT_RT 1343 select DEBUG_RT_MUTEXES if RT_MUTEXES 1344 select DEBUG_LOCK_ALLOC 1345 default n 1346 help 1347 This feature enables tracking lock contention points 1348 1349 For more details, see Documentation/locking/lockstat.rst 1350 1351 This also enables lock events required by "perf lock", 1352 subcommand of perf. 1353 If you want to use "perf lock", you also need to turn on 1354 CONFIG_EVENT_TRACING. 1355 1356 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1357 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1358 1359config DEBUG_RT_MUTEXES 1360 bool "RT Mutex debugging, deadlock detection" 1361 depends on DEBUG_KERNEL && RT_MUTEXES 1362 help 1363 This allows rt mutex semantics violations and rt mutex related 1364 deadlocks (lockups) to be detected and reported automatically. 1365 1366config DEBUG_SPINLOCK 1367 bool "Spinlock and rw-lock debugging: basic checks" 1368 depends on DEBUG_KERNEL 1369 select UNINLINE_SPIN_UNLOCK 1370 help 1371 Say Y here and build SMP to catch missing spinlock initialization 1372 and certain other kinds of spinlock errors commonly made. This is 1373 best used in conjunction with the NMI watchdog so that spinlock 1374 deadlocks are also debuggable. 1375 1376config DEBUG_MUTEXES 1377 bool "Mutex debugging: basic checks" 1378 depends on DEBUG_KERNEL && !PREEMPT_RT 1379 help 1380 This feature allows mutex semantics violations to be detected and 1381 reported. 1382 1383config DEBUG_WW_MUTEX_SLOWPATH 1384 bool "Wait/wound mutex debugging: Slowpath testing" 1385 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1386 select DEBUG_LOCK_ALLOC 1387 select DEBUG_SPINLOCK 1388 select DEBUG_MUTEXES if !PREEMPT_RT 1389 select DEBUG_RT_MUTEXES if PREEMPT_RT 1390 help 1391 This feature enables slowpath testing for w/w mutex users by 1392 injecting additional -EDEADLK wound/backoff cases. Together with 1393 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1394 will test all possible w/w mutex interface abuse with the 1395 exception of simply not acquiring all the required locks. 1396 Note that this feature can introduce significant overhead, so 1397 it really should not be enabled in a production or distro kernel, 1398 even a debug kernel. If you are a driver writer, enable it. If 1399 you are a distro, do not. 1400 1401config DEBUG_RWSEMS 1402 bool "RW Semaphore debugging: basic checks" 1403 depends on DEBUG_KERNEL 1404 help 1405 This debugging feature allows mismatched rw semaphore locks 1406 and unlocks to be detected and reported. 1407 1408config DEBUG_LOCK_ALLOC 1409 bool "Lock debugging: detect incorrect freeing of live locks" 1410 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1411 select DEBUG_SPINLOCK 1412 select DEBUG_MUTEXES if !PREEMPT_RT 1413 select DEBUG_RT_MUTEXES if RT_MUTEXES 1414 select LOCKDEP 1415 help 1416 This feature will check whether any held lock (spinlock, rwlock, 1417 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1418 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1419 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1420 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1421 held during task exit. 1422 1423config LOCKDEP 1424 bool 1425 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1426 select STACKTRACE 1427 select KALLSYMS 1428 select KALLSYMS_ALL 1429 1430config LOCKDEP_SMALL 1431 bool 1432 1433config LOCKDEP_BITS 1434 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1435 depends on LOCKDEP && !LOCKDEP_SMALL 1436 range 10 30 1437 default 15 1438 help 1439 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1440 1441config LOCKDEP_CHAINS_BITS 1442 int "Bitsize for MAX_LOCKDEP_CHAINS" 1443 depends on LOCKDEP && !LOCKDEP_SMALL 1444 range 10 30 1445 default 16 1446 help 1447 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1448 1449config LOCKDEP_STACK_TRACE_BITS 1450 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1451 depends on LOCKDEP && !LOCKDEP_SMALL 1452 range 10 30 1453 default 19 1454 help 1455 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1456 1457config LOCKDEP_STACK_TRACE_HASH_BITS 1458 int "Bitsize for STACK_TRACE_HASH_SIZE" 1459 depends on LOCKDEP && !LOCKDEP_SMALL 1460 range 10 30 1461 default 14 1462 help 1463 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1464 1465config LOCKDEP_CIRCULAR_QUEUE_BITS 1466 int "Bitsize for elements in circular_queue struct" 1467 depends on LOCKDEP 1468 range 10 30 1469 default 12 1470 help 1471 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1472 1473config DEBUG_LOCKDEP 1474 bool "Lock dependency engine debugging" 1475 depends on DEBUG_KERNEL && LOCKDEP 1476 select DEBUG_IRQFLAGS 1477 help 1478 If you say Y here, the lock dependency engine will do 1479 additional runtime checks to debug itself, at the price 1480 of more runtime overhead. 1481 1482config DEBUG_ATOMIC_SLEEP 1483 bool "Sleep inside atomic section checking" 1484 select PREEMPT_COUNT 1485 depends on DEBUG_KERNEL 1486 depends on !ARCH_NO_PREEMPT 1487 help 1488 If you say Y here, various routines which may sleep will become very 1489 noisy if they are called inside atomic sections: when a spinlock is 1490 held, inside an rcu read side critical section, inside preempt disabled 1491 sections, inside an interrupt, etc... 1492 1493config DEBUG_LOCKING_API_SELFTESTS 1494 bool "Locking API boot-time self-tests" 1495 depends on DEBUG_KERNEL 1496 help 1497 Say Y here if you want the kernel to run a short self-test during 1498 bootup. The self-test checks whether common types of locking bugs 1499 are detected by debugging mechanisms or not. (if you disable 1500 lock debugging then those bugs won't be detected of course.) 1501 The following locking APIs are covered: spinlocks, rwlocks, 1502 mutexes and rwsems. 1503 1504config LOCK_TORTURE_TEST 1505 tristate "torture tests for locking" 1506 depends on DEBUG_KERNEL 1507 select TORTURE_TEST 1508 help 1509 This option provides a kernel module that runs torture tests 1510 on kernel locking primitives. The kernel module may be built 1511 after the fact on the running kernel to be tested, if desired. 1512 1513 Say Y here if you want kernel locking-primitive torture tests 1514 to be built into the kernel. 1515 Say M if you want these torture tests to build as a module. 1516 Say N if you are unsure. 1517 1518config WW_MUTEX_SELFTEST 1519 tristate "Wait/wound mutex selftests" 1520 help 1521 This option provides a kernel module that runs tests on the 1522 on the struct ww_mutex locking API. 1523 1524 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1525 with this test harness. 1526 1527 Say M if you want these self tests to build as a module. 1528 Say N if you are unsure. 1529 1530config SCF_TORTURE_TEST 1531 tristate "torture tests for smp_call_function*()" 1532 depends on DEBUG_KERNEL 1533 select TORTURE_TEST 1534 help 1535 This option provides a kernel module that runs torture tests 1536 on the smp_call_function() family of primitives. The kernel 1537 module may be built after the fact on the running kernel to 1538 be tested, if desired. 1539 1540config CSD_LOCK_WAIT_DEBUG 1541 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1542 depends on DEBUG_KERNEL 1543 depends on 64BIT 1544 default n 1545 help 1546 This option enables debug prints when CPUs are slow to respond 1547 to the smp_call_function*() IPI wrappers. These debug prints 1548 include the IPI handler function currently executing (if any) 1549 and relevant stack traces. 1550 1551endmenu # lock debugging 1552 1553config TRACE_IRQFLAGS 1554 depends on TRACE_IRQFLAGS_SUPPORT 1555 bool 1556 help 1557 Enables hooks to interrupt enabling and disabling for 1558 either tracing or lock debugging. 1559 1560config TRACE_IRQFLAGS_NMI 1561 def_bool y 1562 depends on TRACE_IRQFLAGS 1563 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1564 1565config DEBUG_IRQFLAGS 1566 bool "Debug IRQ flag manipulation" 1567 help 1568 Enables checks for potentially unsafe enabling or disabling of 1569 interrupts, such as calling raw_local_irq_restore() when interrupts 1570 are enabled. 1571 1572config STACKTRACE 1573 bool "Stack backtrace support" 1574 depends on STACKTRACE_SUPPORT 1575 help 1576 This option causes the kernel to create a /proc/pid/stack for 1577 every process, showing its current stack trace. 1578 It is also used by various kernel debugging features that require 1579 stack trace generation. 1580 1581config WARN_ALL_UNSEEDED_RANDOM 1582 bool "Warn for all uses of unseeded randomness" 1583 default n 1584 help 1585 Some parts of the kernel contain bugs relating to their use of 1586 cryptographically secure random numbers before it's actually possible 1587 to generate those numbers securely. This setting ensures that these 1588 flaws don't go unnoticed, by enabling a message, should this ever 1589 occur. This will allow people with obscure setups to know when things 1590 are going wrong, so that they might contact developers about fixing 1591 it. 1592 1593 Unfortunately, on some models of some architectures getting 1594 a fully seeded CRNG is extremely difficult, and so this can 1595 result in dmesg getting spammed for a surprisingly long 1596 time. This is really bad from a security perspective, and 1597 so architecture maintainers really need to do what they can 1598 to get the CRNG seeded sooner after the system is booted. 1599 However, since users cannot do anything actionable to 1600 address this, by default this option is disabled. 1601 1602 Say Y here if you want to receive warnings for all uses of 1603 unseeded randomness. This will be of use primarily for 1604 those developers interested in improving the security of 1605 Linux kernels running on their architecture (or 1606 subarchitecture). 1607 1608config DEBUG_KOBJECT 1609 bool "kobject debugging" 1610 depends on DEBUG_KERNEL 1611 help 1612 If you say Y here, some extra kobject debugging messages will be sent 1613 to the syslog. 1614 1615config DEBUG_KOBJECT_RELEASE 1616 bool "kobject release debugging" 1617 depends on DEBUG_OBJECTS_TIMERS 1618 help 1619 kobjects are reference counted objects. This means that their 1620 last reference count put is not predictable, and the kobject can 1621 live on past the point at which a driver decides to drop its 1622 initial reference to the kobject gained on allocation. An 1623 example of this would be a struct device which has just been 1624 unregistered. 1625 1626 However, some buggy drivers assume that after such an operation, 1627 the memory backing the kobject can be immediately freed. This 1628 goes completely against the principles of a refcounted object. 1629 1630 If you say Y here, the kernel will delay the release of kobjects 1631 on the last reference count to improve the visibility of this 1632 kind of kobject release bug. 1633 1634config HAVE_DEBUG_BUGVERBOSE 1635 bool 1636 1637menu "Debug kernel data structures" 1638 1639config DEBUG_LIST 1640 bool "Debug linked list manipulation" 1641 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1642 help 1643 Enable this to turn on extended checks in the linked-list 1644 walking routines. 1645 1646 If unsure, say N. 1647 1648config DEBUG_PLIST 1649 bool "Debug priority linked list manipulation" 1650 depends on DEBUG_KERNEL 1651 help 1652 Enable this to turn on extended checks in the priority-ordered 1653 linked-list (plist) walking routines. This checks the entire 1654 list multiple times during each manipulation. 1655 1656 If unsure, say N. 1657 1658config DEBUG_SG 1659 bool "Debug SG table operations" 1660 depends on DEBUG_KERNEL 1661 help 1662 Enable this to turn on checks on scatter-gather tables. This can 1663 help find problems with drivers that do not properly initialize 1664 their sg tables. 1665 1666 If unsure, say N. 1667 1668config DEBUG_NOTIFIERS 1669 bool "Debug notifier call chains" 1670 depends on DEBUG_KERNEL 1671 help 1672 Enable this to turn on sanity checking for notifier call chains. 1673 This is most useful for kernel developers to make sure that 1674 modules properly unregister themselves from notifier chains. 1675 This is a relatively cheap check but if you care about maximum 1676 performance, say N. 1677 1678config BUG_ON_DATA_CORRUPTION 1679 bool "Trigger a BUG when data corruption is detected" 1680 select DEBUG_LIST 1681 help 1682 Select this option if the kernel should BUG when it encounters 1683 data corruption in kernel memory structures when they get checked 1684 for validity. 1685 1686 If unsure, say N. 1687 1688config DEBUG_MAPLE_TREE 1689 bool "Debug maple trees" 1690 depends on DEBUG_KERNEL 1691 help 1692 Enable maple tree debugging information and extra validations. 1693 1694 If unsure, say N. 1695 1696endmenu 1697 1698config DEBUG_CREDENTIALS 1699 bool "Debug credential management" 1700 depends on DEBUG_KERNEL 1701 help 1702 Enable this to turn on some debug checking for credential 1703 management. The additional code keeps track of the number of 1704 pointers from task_structs to any given cred struct, and checks to 1705 see that this number never exceeds the usage count of the cred 1706 struct. 1707 1708 Furthermore, if SELinux is enabled, this also checks that the 1709 security pointer in the cred struct is never seen to be invalid. 1710 1711 If unsure, say N. 1712 1713source "kernel/rcu/Kconfig.debug" 1714 1715config DEBUG_WQ_FORCE_RR_CPU 1716 bool "Force round-robin CPU selection for unbound work items" 1717 depends on DEBUG_KERNEL 1718 default n 1719 help 1720 Workqueue used to implicitly guarantee that work items queued 1721 without explicit CPU specified are put on the local CPU. This 1722 guarantee is no longer true and while local CPU is still 1723 preferred work items may be put on foreign CPUs. Kernel 1724 parameter "workqueue.debug_force_rr_cpu" is added to force 1725 round-robin CPU selection to flush out usages which depend on the 1726 now broken guarantee. This config option enables the debug 1727 feature by default. When enabled, memory and cache locality will 1728 be impacted. 1729 1730config CPU_HOTPLUG_STATE_CONTROL 1731 bool "Enable CPU hotplug state control" 1732 depends on DEBUG_KERNEL 1733 depends on HOTPLUG_CPU 1734 default n 1735 help 1736 Allows to write steps between "offline" and "online" to the CPUs 1737 sysfs target file so states can be stepped granular. This is a debug 1738 option for now as the hotplug machinery cannot be stopped and 1739 restarted at arbitrary points yet. 1740 1741 Say N if your are unsure. 1742 1743config LATENCYTOP 1744 bool "Latency measuring infrastructure" 1745 depends on DEBUG_KERNEL 1746 depends on STACKTRACE_SUPPORT 1747 depends on PROC_FS 1748 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1749 select KALLSYMS 1750 select KALLSYMS_ALL 1751 select STACKTRACE 1752 select SCHEDSTATS 1753 help 1754 Enable this option if you want to use the LatencyTOP tool 1755 to find out which userspace is blocking on what kernel operations. 1756 1757config DEBUG_CGROUP_REF 1758 bool "Disable inlining of cgroup css reference count functions" 1759 depends on DEBUG_KERNEL 1760 depends on CGROUPS 1761 depends on KPROBES 1762 default n 1763 help 1764 Force cgroup css reference count functions to not be inlined so 1765 that they can be kprobed for debugging. 1766 1767source "kernel/trace/Kconfig" 1768 1769config PROVIDE_OHCI1394_DMA_INIT 1770 bool "Remote debugging over FireWire early on boot" 1771 depends on PCI && X86 1772 help 1773 If you want to debug problems which hang or crash the kernel early 1774 on boot and the crashing machine has a FireWire port, you can use 1775 this feature to remotely access the memory of the crashed machine 1776 over FireWire. This employs remote DMA as part of the OHCI1394 1777 specification which is now the standard for FireWire controllers. 1778 1779 With remote DMA, you can monitor the printk buffer remotely using 1780 firescope and access all memory below 4GB using fireproxy from gdb. 1781 Even controlling a kernel debugger is possible using remote DMA. 1782 1783 Usage: 1784 1785 If ohci1394_dma=early is used as boot parameter, it will initialize 1786 all OHCI1394 controllers which are found in the PCI config space. 1787 1788 As all changes to the FireWire bus such as enabling and disabling 1789 devices cause a bus reset and thereby disable remote DMA for all 1790 devices, be sure to have the cable plugged and FireWire enabled on 1791 the debugging host before booting the debug target for debugging. 1792 1793 This code (~1k) is freed after boot. By then, the firewire stack 1794 in charge of the OHCI-1394 controllers should be used instead. 1795 1796 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1797 1798source "samples/Kconfig" 1799 1800config ARCH_HAS_DEVMEM_IS_ALLOWED 1801 bool 1802 1803config STRICT_DEVMEM 1804 bool "Filter access to /dev/mem" 1805 depends on MMU && DEVMEM 1806 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1807 default y if PPC || X86 || ARM64 1808 help 1809 If this option is disabled, you allow userspace (root) access to all 1810 of memory, including kernel and userspace memory. Accidental 1811 access to this is obviously disastrous, but specific access can 1812 be used by people debugging the kernel. Note that with PAT support 1813 enabled, even in this case there are restrictions on /dev/mem 1814 use due to the cache aliasing requirements. 1815 1816 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1817 file only allows userspace access to PCI space and the BIOS code and 1818 data regions. This is sufficient for dosemu and X and all common 1819 users of /dev/mem. 1820 1821 If in doubt, say Y. 1822 1823config IO_STRICT_DEVMEM 1824 bool "Filter I/O access to /dev/mem" 1825 depends on STRICT_DEVMEM 1826 help 1827 If this option is disabled, you allow userspace (root) access to all 1828 io-memory regardless of whether a driver is actively using that 1829 range. Accidental access to this is obviously disastrous, but 1830 specific access can be used by people debugging kernel drivers. 1831 1832 If this option is switched on, the /dev/mem file only allows 1833 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1834 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1835 if the driver using a given range cannot be disabled. 1836 1837 If in doubt, say Y. 1838 1839menu "$(SRCARCH) Debugging" 1840 1841source "arch/$(SRCARCH)/Kconfig.debug" 1842 1843endmenu 1844 1845menu "Kernel Testing and Coverage" 1846 1847source "lib/kunit/Kconfig" 1848 1849config NOTIFIER_ERROR_INJECTION 1850 tristate "Notifier error injection" 1851 depends on DEBUG_KERNEL 1852 select DEBUG_FS 1853 help 1854 This option provides the ability to inject artificial errors to 1855 specified notifier chain callbacks. It is useful to test the error 1856 handling of notifier call chain failures. 1857 1858 Say N if unsure. 1859 1860config PM_NOTIFIER_ERROR_INJECT 1861 tristate "PM notifier error injection module" 1862 depends on PM && NOTIFIER_ERROR_INJECTION 1863 default m if PM_DEBUG 1864 help 1865 This option provides the ability to inject artificial errors to 1866 PM notifier chain callbacks. It is controlled through debugfs 1867 interface /sys/kernel/debug/notifier-error-inject/pm 1868 1869 If the notifier call chain should be failed with some events 1870 notified, write the error code to "actions/<notifier event>/error". 1871 1872 Example: Inject PM suspend error (-12 = -ENOMEM) 1873 1874 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1875 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1876 # echo mem > /sys/power/state 1877 bash: echo: write error: Cannot allocate memory 1878 1879 To compile this code as a module, choose M here: the module will 1880 be called pm-notifier-error-inject. 1881 1882 If unsure, say N. 1883 1884config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1885 tristate "OF reconfig notifier error injection module" 1886 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1887 help 1888 This option provides the ability to inject artificial errors to 1889 OF reconfig notifier chain callbacks. It is controlled 1890 through debugfs interface under 1891 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1892 1893 If the notifier call chain should be failed with some events 1894 notified, write the error code to "actions/<notifier event>/error". 1895 1896 To compile this code as a module, choose M here: the module will 1897 be called of-reconfig-notifier-error-inject. 1898 1899 If unsure, say N. 1900 1901config NETDEV_NOTIFIER_ERROR_INJECT 1902 tristate "Netdev notifier error injection module" 1903 depends on NET && NOTIFIER_ERROR_INJECTION 1904 help 1905 This option provides the ability to inject artificial errors to 1906 netdevice notifier chain callbacks. It is controlled through debugfs 1907 interface /sys/kernel/debug/notifier-error-inject/netdev 1908 1909 If the notifier call chain should be failed with some events 1910 notified, write the error code to "actions/<notifier event>/error". 1911 1912 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1913 1914 # cd /sys/kernel/debug/notifier-error-inject/netdev 1915 # echo -22 > actions/NETDEV_CHANGEMTU/error 1916 # ip link set eth0 mtu 1024 1917 RTNETLINK answers: Invalid argument 1918 1919 To compile this code as a module, choose M here: the module will 1920 be called netdev-notifier-error-inject. 1921 1922 If unsure, say N. 1923 1924config FUNCTION_ERROR_INJECTION 1925 bool "Fault-injections of functions" 1926 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1927 help 1928 Add fault injections into various functions that are annotated with 1929 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1930 value of these functions. This is useful to test error paths of code. 1931 1932 If unsure, say N 1933 1934config FAULT_INJECTION 1935 bool "Fault-injection framework" 1936 depends on DEBUG_KERNEL 1937 help 1938 Provide fault-injection framework. 1939 For more details, see Documentation/fault-injection/. 1940 1941config FAILSLAB 1942 bool "Fault-injection capability for kmalloc" 1943 depends on FAULT_INJECTION 1944 depends on SLAB || SLUB 1945 help 1946 Provide fault-injection capability for kmalloc. 1947 1948config FAIL_PAGE_ALLOC 1949 bool "Fault-injection capability for alloc_pages()" 1950 depends on FAULT_INJECTION 1951 help 1952 Provide fault-injection capability for alloc_pages(). 1953 1954config FAULT_INJECTION_USERCOPY 1955 bool "Fault injection capability for usercopy functions" 1956 depends on FAULT_INJECTION 1957 help 1958 Provides fault-injection capability to inject failures 1959 in usercopy functions (copy_from_user(), get_user(), ...). 1960 1961config FAIL_MAKE_REQUEST 1962 bool "Fault-injection capability for disk IO" 1963 depends on FAULT_INJECTION && BLOCK 1964 help 1965 Provide fault-injection capability for disk IO. 1966 1967config FAIL_IO_TIMEOUT 1968 bool "Fault-injection capability for faking disk interrupts" 1969 depends on FAULT_INJECTION && BLOCK 1970 help 1971 Provide fault-injection capability on end IO handling. This 1972 will make the block layer "forget" an interrupt as configured, 1973 thus exercising the error handling. 1974 1975 Only works with drivers that use the generic timeout handling, 1976 for others it won't do anything. 1977 1978config FAIL_FUTEX 1979 bool "Fault-injection capability for futexes" 1980 select DEBUG_FS 1981 depends on FAULT_INJECTION && FUTEX 1982 help 1983 Provide fault-injection capability for futexes. 1984 1985config FAULT_INJECTION_DEBUG_FS 1986 bool "Debugfs entries for fault-injection capabilities" 1987 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1988 help 1989 Enable configuration of fault-injection capabilities via debugfs. 1990 1991config FAIL_FUNCTION 1992 bool "Fault-injection capability for functions" 1993 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1994 help 1995 Provide function-based fault-injection capability. 1996 This will allow you to override a specific function with a return 1997 with given return value. As a result, function caller will see 1998 an error value and have to handle it. This is useful to test the 1999 error handling in various subsystems. 2000 2001config FAIL_MMC_REQUEST 2002 bool "Fault-injection capability for MMC IO" 2003 depends on FAULT_INJECTION_DEBUG_FS && MMC 2004 help 2005 Provide fault-injection capability for MMC IO. 2006 This will make the mmc core return data errors. This is 2007 useful to test the error handling in the mmc block device 2008 and to test how the mmc host driver handles retries from 2009 the block device. 2010 2011config FAIL_SUNRPC 2012 bool "Fault-injection capability for SunRPC" 2013 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2014 help 2015 Provide fault-injection capability for SunRPC and 2016 its consumers. 2017 2018config FAULT_INJECTION_STACKTRACE_FILTER 2019 bool "stacktrace filter for fault-injection capabilities" 2020 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 2021 select STACKTRACE 2022 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2023 help 2024 Provide stacktrace filter for fault-injection capabilities 2025 2026config ARCH_HAS_KCOV 2027 bool 2028 help 2029 An architecture should select this when it can successfully 2030 build and run with CONFIG_KCOV. This typically requires 2031 disabling instrumentation for some early boot code. 2032 2033config CC_HAS_SANCOV_TRACE_PC 2034 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2035 2036 2037config KCOV 2038 bool "Code coverage for fuzzing" 2039 depends on ARCH_HAS_KCOV 2040 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2041 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2042 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2043 select DEBUG_FS 2044 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2045 select OBJTOOL if HAVE_NOINSTR_HACK 2046 help 2047 KCOV exposes kernel code coverage information in a form suitable 2048 for coverage-guided fuzzing (randomized testing). 2049 2050 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2051 different machines and across reboots. If you need stable PC values, 2052 disable RANDOMIZE_BASE. 2053 2054 For more details, see Documentation/dev-tools/kcov.rst. 2055 2056config KCOV_ENABLE_COMPARISONS 2057 bool "Enable comparison operands collection by KCOV" 2058 depends on KCOV 2059 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2060 help 2061 KCOV also exposes operands of every comparison in the instrumented 2062 code along with operand sizes and PCs of the comparison instructions. 2063 These operands can be used by fuzzing engines to improve the quality 2064 of fuzzing coverage. 2065 2066config KCOV_INSTRUMENT_ALL 2067 bool "Instrument all code by default" 2068 depends on KCOV 2069 default y 2070 help 2071 If you are doing generic system call fuzzing (like e.g. syzkaller), 2072 then you will want to instrument the whole kernel and you should 2073 say y here. If you are doing more targeted fuzzing (like e.g. 2074 filesystem fuzzing with AFL) then you will want to enable coverage 2075 for more specific subsets of files, and should say n here. 2076 2077config KCOV_IRQ_AREA_SIZE 2078 hex "Size of interrupt coverage collection area in words" 2079 depends on KCOV 2080 default 0x40000 2081 help 2082 KCOV uses preallocated per-cpu areas to collect coverage from 2083 soft interrupts. This specifies the size of those areas in the 2084 number of unsigned long words. 2085 2086menuconfig RUNTIME_TESTING_MENU 2087 bool "Runtime Testing" 2088 def_bool y 2089 2090if RUNTIME_TESTING_MENU 2091 2092config LKDTM 2093 tristate "Linux Kernel Dump Test Tool Module" 2094 depends on DEBUG_FS 2095 help 2096 This module enables testing of the different dumping mechanisms by 2097 inducing system failures at predefined crash points. 2098 If you don't need it: say N 2099 Choose M here to compile this code as a module. The module will be 2100 called lkdtm. 2101 2102 Documentation on how to use the module can be found in 2103 Documentation/fault-injection/provoke-crashes.rst 2104 2105config CPUMASK_KUNIT_TEST 2106 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2107 depends on KUNIT 2108 default KUNIT_ALL_TESTS 2109 help 2110 Enable to turn on cpumask tests, running at boot or module load time. 2111 2112 For more information on KUnit and unit tests in general, please refer 2113 to the KUnit documentation in Documentation/dev-tools/kunit/. 2114 2115 If unsure, say N. 2116 2117config TEST_LIST_SORT 2118 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2119 depends on KUNIT 2120 default KUNIT_ALL_TESTS 2121 help 2122 Enable this to turn on 'list_sort()' function test. This test is 2123 executed only once during system boot (so affects only boot time), 2124 or at module load time. 2125 2126 If unsure, say N. 2127 2128config TEST_MIN_HEAP 2129 tristate "Min heap test" 2130 depends on DEBUG_KERNEL || m 2131 help 2132 Enable this to turn on min heap function tests. This test is 2133 executed only once during system boot (so affects only boot time), 2134 or at module load time. 2135 2136 If unsure, say N. 2137 2138config TEST_SORT 2139 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2140 depends on KUNIT 2141 default KUNIT_ALL_TESTS 2142 help 2143 This option enables the self-test function of 'sort()' at boot, 2144 or at module load time. 2145 2146 If unsure, say N. 2147 2148config TEST_DIV64 2149 tristate "64bit/32bit division and modulo test" 2150 depends on DEBUG_KERNEL || m 2151 help 2152 Enable this to turn on 'do_div()' function test. This test is 2153 executed only once during system boot (so affects only boot time), 2154 or at module load time. 2155 2156 If unsure, say N. 2157 2158config KPROBES_SANITY_TEST 2159 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2160 depends on DEBUG_KERNEL 2161 depends on KPROBES 2162 depends on KUNIT 2163 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2164 default KUNIT_ALL_TESTS 2165 help 2166 This option provides for testing basic kprobes functionality on 2167 boot. Samples of kprobe and kretprobe are inserted and 2168 verified for functionality. 2169 2170 Say N if you are unsure. 2171 2172config FPROBE_SANITY_TEST 2173 bool "Self test for fprobe" 2174 depends on DEBUG_KERNEL 2175 depends on FPROBE 2176 depends on KUNIT=y 2177 help 2178 This option will enable testing the fprobe when the system boot. 2179 A series of tests are made to verify that the fprobe is functioning 2180 properly. 2181 2182 Say N if you are unsure. 2183 2184config BACKTRACE_SELF_TEST 2185 tristate "Self test for the backtrace code" 2186 depends on DEBUG_KERNEL 2187 help 2188 This option provides a kernel module that can be used to test 2189 the kernel stack backtrace code. This option is not useful 2190 for distributions or general kernels, but only for kernel 2191 developers working on architecture code. 2192 2193 Note that if you want to also test saved backtraces, you will 2194 have to enable STACKTRACE as well. 2195 2196 Say N if you are unsure. 2197 2198config TEST_REF_TRACKER 2199 tristate "Self test for reference tracker" 2200 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2201 select REF_TRACKER 2202 help 2203 This option provides a kernel module performing tests 2204 using reference tracker infrastructure. 2205 2206 Say N if you are unsure. 2207 2208config RBTREE_TEST 2209 tristate "Red-Black tree test" 2210 depends on DEBUG_KERNEL 2211 help 2212 A benchmark measuring the performance of the rbtree library. 2213 Also includes rbtree invariant checks. 2214 2215config REED_SOLOMON_TEST 2216 tristate "Reed-Solomon library test" 2217 depends on DEBUG_KERNEL || m 2218 select REED_SOLOMON 2219 select REED_SOLOMON_ENC16 2220 select REED_SOLOMON_DEC16 2221 help 2222 This option enables the self-test function of rslib at boot, 2223 or at module load time. 2224 2225 If unsure, say N. 2226 2227config INTERVAL_TREE_TEST 2228 tristate "Interval tree test" 2229 depends on DEBUG_KERNEL 2230 select INTERVAL_TREE 2231 help 2232 A benchmark measuring the performance of the interval tree library 2233 2234config PERCPU_TEST 2235 tristate "Per cpu operations test" 2236 depends on m && DEBUG_KERNEL 2237 help 2238 Enable this option to build test module which validates per-cpu 2239 operations. 2240 2241 If unsure, say N. 2242 2243config ATOMIC64_SELFTEST 2244 tristate "Perform an atomic64_t self-test" 2245 help 2246 Enable this option to test the atomic64_t functions at boot or 2247 at module load time. 2248 2249 If unsure, say N. 2250 2251config ASYNC_RAID6_TEST 2252 tristate "Self test for hardware accelerated raid6 recovery" 2253 depends on ASYNC_RAID6_RECOV 2254 select ASYNC_MEMCPY 2255 help 2256 This is a one-shot self test that permutes through the 2257 recovery of all the possible two disk failure scenarios for a 2258 N-disk array. Recovery is performed with the asynchronous 2259 raid6 recovery routines, and will optionally use an offload 2260 engine if one is available. 2261 2262 If unsure, say N. 2263 2264config TEST_HEXDUMP 2265 tristate "Test functions located in the hexdump module at runtime" 2266 2267config STRING_SELFTEST 2268 tristate "Test string functions at runtime" 2269 2270config TEST_STRING_HELPERS 2271 tristate "Test functions located in the string_helpers module at runtime" 2272 2273config TEST_KSTRTOX 2274 tristate "Test kstrto*() family of functions at runtime" 2275 2276config TEST_PRINTF 2277 tristate "Test printf() family of functions at runtime" 2278 2279config TEST_SCANF 2280 tristate "Test scanf() family of functions at runtime" 2281 2282config TEST_BITMAP 2283 tristate "Test bitmap_*() family of functions at runtime" 2284 help 2285 Enable this option to test the bitmap functions at boot. 2286 2287 If unsure, say N. 2288 2289config TEST_UUID 2290 tristate "Test functions located in the uuid module at runtime" 2291 2292config TEST_XARRAY 2293 tristate "Test the XArray code at runtime" 2294 2295config TEST_MAPLE_TREE 2296 depends on DEBUG_KERNEL 2297 select DEBUG_MAPLE_TREE 2298 tristate "Test the Maple Tree code at runtime" 2299 2300config TEST_RHASHTABLE 2301 tristate "Perform selftest on resizable hash table" 2302 help 2303 Enable this option to test the rhashtable functions at boot. 2304 2305 If unsure, say N. 2306 2307config TEST_IDA 2308 tristate "Perform selftest on IDA functions" 2309 2310config TEST_PARMAN 2311 tristate "Perform selftest on priority array manager" 2312 depends on PARMAN 2313 help 2314 Enable this option to test priority array manager on boot 2315 (or module load). 2316 2317 If unsure, say N. 2318 2319config TEST_IRQ_TIMINGS 2320 bool "IRQ timings selftest" 2321 depends on IRQ_TIMINGS 2322 help 2323 Enable this option to test the irq timings code on boot. 2324 2325 If unsure, say N. 2326 2327config TEST_LKM 2328 tristate "Test module loading with 'hello world' module" 2329 depends on m 2330 help 2331 This builds the "test_module" module that emits "Hello, world" 2332 on printk when loaded. It is designed to be used for basic 2333 evaluation of the module loading subsystem (for example when 2334 validating module verification). It lacks any extra dependencies, 2335 and will not normally be loaded by the system unless explicitly 2336 requested by name. 2337 2338 If unsure, say N. 2339 2340config TEST_BITOPS 2341 tristate "Test module for compilation of bitops operations" 2342 depends on m 2343 help 2344 This builds the "test_bitops" module that is much like the 2345 TEST_LKM module except that it does a basic exercise of the 2346 set/clear_bit macros and get_count_order/long to make sure there are 2347 no compiler warnings from C=1 sparse checker or -Wextra 2348 compilations. It has no dependencies and doesn't run or load unless 2349 explicitly requested by name. for example: modprobe test_bitops. 2350 2351 If unsure, say N. 2352 2353config TEST_VMALLOC 2354 tristate "Test module for stress/performance analysis of vmalloc allocator" 2355 default n 2356 depends on MMU 2357 depends on m 2358 help 2359 This builds the "test_vmalloc" module that should be used for 2360 stress and performance analysis. So, any new change for vmalloc 2361 subsystem can be evaluated from performance and stability point 2362 of view. 2363 2364 If unsure, say N. 2365 2366config TEST_USER_COPY 2367 tristate "Test user/kernel boundary protections" 2368 depends on m 2369 help 2370 This builds the "test_user_copy" module that runs sanity checks 2371 on the copy_to/from_user infrastructure, making sure basic 2372 user/kernel boundary testing is working. If it fails to load, 2373 a regression has been detected in the user/kernel memory boundary 2374 protections. 2375 2376 If unsure, say N. 2377 2378config TEST_BPF 2379 tristate "Test BPF filter functionality" 2380 depends on m && NET 2381 help 2382 This builds the "test_bpf" module that runs various test vectors 2383 against the BPF interpreter or BPF JIT compiler depending on the 2384 current setting. This is in particular useful for BPF JIT compiler 2385 development, but also to run regression tests against changes in 2386 the interpreter code. It also enables test stubs for eBPF maps and 2387 verifier used by user space verifier testsuite. 2388 2389 If unsure, say N. 2390 2391config TEST_BLACKHOLE_DEV 2392 tristate "Test blackhole netdev functionality" 2393 depends on m && NET 2394 help 2395 This builds the "test_blackhole_dev" module that validates the 2396 data path through this blackhole netdev. 2397 2398 If unsure, say N. 2399 2400config FIND_BIT_BENCHMARK 2401 tristate "Test find_bit functions" 2402 help 2403 This builds the "test_find_bit" module that measure find_*_bit() 2404 functions performance. 2405 2406 If unsure, say N. 2407 2408config TEST_FIRMWARE 2409 tristate "Test firmware loading via userspace interface" 2410 depends on FW_LOADER 2411 help 2412 This builds the "test_firmware" module that creates a userspace 2413 interface for testing firmware loading. This can be used to 2414 control the triggering of firmware loading without needing an 2415 actual firmware-using device. The contents can be rechecked by 2416 userspace. 2417 2418 If unsure, say N. 2419 2420config TEST_SYSCTL 2421 tristate "sysctl test driver" 2422 depends on PROC_SYSCTL 2423 help 2424 This builds the "test_sysctl" module. This driver enables to test the 2425 proc sysctl interfaces available to drivers safely without affecting 2426 production knobs which might alter system functionality. 2427 2428 If unsure, say N. 2429 2430config BITFIELD_KUNIT 2431 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2432 depends on KUNIT 2433 default KUNIT_ALL_TESTS 2434 help 2435 Enable this option to test the bitfield functions at boot. 2436 2437 KUnit tests run during boot and output the results to the debug log 2438 in TAP format (http://testanything.org/). Only useful for kernel devs 2439 running the KUnit test harness, and not intended for inclusion into a 2440 production build. 2441 2442 For more information on KUnit and unit tests in general please refer 2443 to the KUnit documentation in Documentation/dev-tools/kunit/. 2444 2445 If unsure, say N. 2446 2447config HASH_KUNIT_TEST 2448 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2449 depends on KUNIT 2450 default KUNIT_ALL_TESTS 2451 help 2452 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2453 integer (<linux/hash.h>) hash functions on boot. 2454 2455 KUnit tests run during boot and output the results to the debug log 2456 in TAP format (https://testanything.org/). Only useful for kernel devs 2457 running the KUnit test harness, and not intended for inclusion into a 2458 production build. 2459 2460 For more information on KUnit and unit tests in general please refer 2461 to the KUnit documentation in Documentation/dev-tools/kunit/. 2462 2463 This is intended to help people writing architecture-specific 2464 optimized versions. If unsure, say N. 2465 2466config RESOURCE_KUNIT_TEST 2467 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2468 depends on KUNIT 2469 default KUNIT_ALL_TESTS 2470 help 2471 This builds the resource API unit test. 2472 Tests the logic of API provided by resource.c and ioport.h. 2473 For more information on KUnit and unit tests in general please refer 2474 to the KUnit documentation in Documentation/dev-tools/kunit/. 2475 2476 If unsure, say N. 2477 2478config SYSCTL_KUNIT_TEST 2479 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2480 depends on KUNIT 2481 default KUNIT_ALL_TESTS 2482 help 2483 This builds the proc sysctl unit test, which runs on boot. 2484 Tests the API contract and implementation correctness of sysctl. 2485 For more information on KUnit and unit tests in general please refer 2486 to the KUnit documentation in Documentation/dev-tools/kunit/. 2487 2488 If unsure, say N. 2489 2490config LIST_KUNIT_TEST 2491 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2492 depends on KUNIT 2493 default KUNIT_ALL_TESTS 2494 help 2495 This builds the linked list KUnit test suite. 2496 It tests that the API and basic functionality of the list_head type 2497 and associated macros. 2498 2499 KUnit tests run during boot and output the results to the debug log 2500 in TAP format (https://testanything.org/). Only useful for kernel devs 2501 running the KUnit test harness, and not intended for inclusion into a 2502 production build. 2503 2504 For more information on KUnit and unit tests in general please refer 2505 to the KUnit documentation in Documentation/dev-tools/kunit/. 2506 2507 If unsure, say N. 2508 2509config LINEAR_RANGES_TEST 2510 tristate "KUnit test for linear_ranges" 2511 depends on KUNIT 2512 select LINEAR_RANGES 2513 help 2514 This builds the linear_ranges unit test, which runs on boot. 2515 Tests the linear_ranges logic correctness. 2516 For more information on KUnit and unit tests in general please refer 2517 to the KUnit documentation in Documentation/dev-tools/kunit/. 2518 2519 If unsure, say N. 2520 2521config CMDLINE_KUNIT_TEST 2522 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2523 depends on KUNIT 2524 default KUNIT_ALL_TESTS 2525 help 2526 This builds the cmdline API unit test. 2527 Tests the logic of API provided by cmdline.c. 2528 For more information on KUnit and unit tests in general please refer 2529 to the KUnit documentation in Documentation/dev-tools/kunit/. 2530 2531 If unsure, say N. 2532 2533config BITS_TEST 2534 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2535 depends on KUNIT 2536 default KUNIT_ALL_TESTS 2537 help 2538 This builds the bits unit test. 2539 Tests the logic of macros defined in bits.h. 2540 For more information on KUnit and unit tests in general please refer 2541 to the KUnit documentation in Documentation/dev-tools/kunit/. 2542 2543 If unsure, say N. 2544 2545config SLUB_KUNIT_TEST 2546 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2547 depends on SLUB_DEBUG && KUNIT 2548 default KUNIT_ALL_TESTS 2549 help 2550 This builds SLUB allocator unit test. 2551 Tests SLUB cache debugging functionality. 2552 For more information on KUnit and unit tests in general please refer 2553 to the KUnit documentation in Documentation/dev-tools/kunit/. 2554 2555 If unsure, say N. 2556 2557config RATIONAL_KUNIT_TEST 2558 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2559 depends on KUNIT && RATIONAL 2560 default KUNIT_ALL_TESTS 2561 help 2562 This builds the rational math unit test. 2563 For more information on KUnit and unit tests in general please refer 2564 to the KUnit documentation in Documentation/dev-tools/kunit/. 2565 2566 If unsure, say N. 2567 2568config MEMCPY_KUNIT_TEST 2569 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2570 depends on KUNIT 2571 default KUNIT_ALL_TESTS 2572 help 2573 Builds unit tests for memcpy(), memmove(), and memset() functions. 2574 For more information on KUnit and unit tests in general please refer 2575 to the KUnit documentation in Documentation/dev-tools/kunit/. 2576 2577 If unsure, say N. 2578 2579config MEMCPY_SLOW_KUNIT_TEST 2580 bool "Include exhaustive memcpy tests" 2581 depends on MEMCPY_KUNIT_TEST 2582 default y 2583 help 2584 Some memcpy tests are quite exhaustive in checking for overlaps 2585 and bit ranges. These can be very slow, so they are split out 2586 as a separate config, in case they need to be disabled. 2587 2588config IS_SIGNED_TYPE_KUNIT_TEST 2589 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2590 depends on KUNIT 2591 default KUNIT_ALL_TESTS 2592 help 2593 Builds unit tests for the is_signed_type() macro. 2594 2595 For more information on KUnit and unit tests in general please refer 2596 to the KUnit documentation in Documentation/dev-tools/kunit/. 2597 2598 If unsure, say N. 2599 2600config OVERFLOW_KUNIT_TEST 2601 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2602 depends on KUNIT 2603 default KUNIT_ALL_TESTS 2604 help 2605 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2606 related functions. 2607 2608 For more information on KUnit and unit tests in general please refer 2609 to the KUnit documentation in Documentation/dev-tools/kunit/. 2610 2611 If unsure, say N. 2612 2613config STACKINIT_KUNIT_TEST 2614 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2615 depends on KUNIT 2616 default KUNIT_ALL_TESTS 2617 help 2618 Test if the kernel is zero-initializing stack variables and 2619 padding. Coverage is controlled by compiler flags, 2620 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2621 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2622 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2623 2624config FORTIFY_KUNIT_TEST 2625 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2626 depends on KUNIT && FORTIFY_SOURCE 2627 default KUNIT_ALL_TESTS 2628 help 2629 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2630 by the str*() and mem*() family of functions. For testing runtime 2631 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2632 2633config HW_BREAKPOINT_KUNIT_TEST 2634 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2635 depends on HAVE_HW_BREAKPOINT 2636 depends on KUNIT=y 2637 default KUNIT_ALL_TESTS 2638 help 2639 Tests for hw_breakpoint constraints accounting. 2640 2641 If unsure, say N. 2642 2643config STRSCPY_KUNIT_TEST 2644 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2645 depends on KUNIT 2646 default KUNIT_ALL_TESTS 2647 2648config SIPHASH_KUNIT_TEST 2649 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2650 depends on KUNIT 2651 default KUNIT_ALL_TESTS 2652 help 2653 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2654 functions on boot (or module load). 2655 2656 This is intended to help people writing architecture-specific 2657 optimized versions. If unsure, say N. 2658 2659config TEST_UDELAY 2660 tristate "udelay test driver" 2661 help 2662 This builds the "udelay_test" module that helps to make sure 2663 that udelay() is working properly. 2664 2665 If unsure, say N. 2666 2667config TEST_STATIC_KEYS 2668 tristate "Test static keys" 2669 depends on m 2670 help 2671 Test the static key interfaces. 2672 2673 If unsure, say N. 2674 2675config TEST_DYNAMIC_DEBUG 2676 tristate "Test DYNAMIC_DEBUG" 2677 depends on DYNAMIC_DEBUG 2678 help 2679 This module registers a tracer callback to count enabled 2680 pr_debugs in a 'do_debugging' function, then alters their 2681 enablements, calls the function, and compares counts. 2682 2683 If unsure, say N. 2684 2685config TEST_KMOD 2686 tristate "kmod stress tester" 2687 depends on m 2688 depends on NETDEVICES && NET_CORE && INET # for TUN 2689 depends on BLOCK 2690 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2691 select TEST_LKM 2692 select XFS_FS 2693 select TUN 2694 select BTRFS_FS 2695 help 2696 Test the kernel's module loading mechanism: kmod. kmod implements 2697 support to load modules using the Linux kernel's usermode helper. 2698 This test provides a series of tests against kmod. 2699 2700 Although technically you can either build test_kmod as a module or 2701 into the kernel we disallow building it into the kernel since 2702 it stress tests request_module() and this will very likely cause 2703 some issues by taking over precious threads available from other 2704 module load requests, ultimately this could be fatal. 2705 2706 To run tests run: 2707 2708 tools/testing/selftests/kmod/kmod.sh --help 2709 2710 If unsure, say N. 2711 2712config TEST_DEBUG_VIRTUAL 2713 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2714 depends on DEBUG_VIRTUAL 2715 help 2716 Test the kernel's ability to detect incorrect calls to 2717 virt_to_phys() done against the non-linear part of the 2718 kernel's virtual address map. 2719 2720 If unsure, say N. 2721 2722config TEST_MEMCAT_P 2723 tristate "Test memcat_p() helper function" 2724 help 2725 Test the memcat_p() helper for correctly merging two 2726 pointer arrays together. 2727 2728 If unsure, say N. 2729 2730config TEST_LIVEPATCH 2731 tristate "Test livepatching" 2732 default n 2733 depends on DYNAMIC_DEBUG 2734 depends on LIVEPATCH 2735 depends on m 2736 help 2737 Test kernel livepatching features for correctness. The tests will 2738 load test modules that will be livepatched in various scenarios. 2739 2740 To run all the livepatching tests: 2741 2742 make -C tools/testing/selftests TARGETS=livepatch run_tests 2743 2744 Alternatively, individual tests may be invoked: 2745 2746 tools/testing/selftests/livepatch/test-callbacks.sh 2747 tools/testing/selftests/livepatch/test-livepatch.sh 2748 tools/testing/selftests/livepatch/test-shadow-vars.sh 2749 2750 If unsure, say N. 2751 2752config TEST_OBJAGG 2753 tristate "Perform selftest on object aggreration manager" 2754 default n 2755 depends on OBJAGG 2756 help 2757 Enable this option to test object aggregation manager on boot 2758 (or module load). 2759 2760config TEST_MEMINIT 2761 tristate "Test heap/page initialization" 2762 help 2763 Test if the kernel is zero-initializing heap and page allocations. 2764 This can be useful to test init_on_alloc and init_on_free features. 2765 2766 If unsure, say N. 2767 2768config TEST_HMM 2769 tristate "Test HMM (Heterogeneous Memory Management)" 2770 depends on TRANSPARENT_HUGEPAGE 2771 depends on DEVICE_PRIVATE 2772 select HMM_MIRROR 2773 select MMU_NOTIFIER 2774 help 2775 This is a pseudo device driver solely for testing HMM. 2776 Say M here if you want to build the HMM test module. 2777 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2778 2779 If unsure, say N. 2780 2781config TEST_FREE_PAGES 2782 tristate "Test freeing pages" 2783 help 2784 Test that a memory leak does not occur due to a race between 2785 freeing a block of pages and a speculative page reference. 2786 Loading this module is safe if your kernel has the bug fixed. 2787 If the bug is not fixed, it will leak gigabytes of memory and 2788 probably OOM your system. 2789 2790config TEST_FPU 2791 tristate "Test floating point operations in kernel space" 2792 depends on X86 && !KCOV_INSTRUMENT_ALL 2793 help 2794 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2795 which will trigger a sequence of floating point operations. This is used 2796 for self-testing floating point control register setting in 2797 kernel_fpu_begin(). 2798 2799 If unsure, say N. 2800 2801config TEST_CLOCKSOURCE_WATCHDOG 2802 tristate "Test clocksource watchdog in kernel space" 2803 depends on CLOCKSOURCE_WATCHDOG 2804 help 2805 Enable this option to create a kernel module that will trigger 2806 a test of the clocksource watchdog. This module may be loaded 2807 via modprobe or insmod in which case it will run upon being 2808 loaded, or it may be built in, in which case it will run 2809 shortly after boot. 2810 2811 If unsure, say N. 2812 2813endif # RUNTIME_TESTING_MENU 2814 2815config ARCH_USE_MEMTEST 2816 bool 2817 help 2818 An architecture should select this when it uses early_memtest() 2819 during boot process. 2820 2821config MEMTEST 2822 bool "Memtest" 2823 depends on ARCH_USE_MEMTEST 2824 help 2825 This option adds a kernel parameter 'memtest', which allows memtest 2826 to be set and executed. 2827 memtest=0, mean disabled; -- default 2828 memtest=1, mean do 1 test pattern; 2829 ... 2830 memtest=17, mean do 17 test patterns. 2831 If you are unsure how to answer this question, answer N. 2832 2833 2834 2835config HYPERV_TESTING 2836 bool "Microsoft Hyper-V driver testing" 2837 default n 2838 depends on HYPERV && DEBUG_FS 2839 help 2840 Select this option to enable Hyper-V vmbus testing. 2841 2842endmenu # "Kernel Testing and Coverage" 2843 2844menu "Rust hacking" 2845 2846config RUST_DEBUG_ASSERTIONS 2847 bool "Debug assertions" 2848 depends on RUST 2849 help 2850 Enables rustc's `-Cdebug-assertions` codegen option. 2851 2852 This flag lets you turn `cfg(debug_assertions)` conditional 2853 compilation on or off. This can be used to enable extra debugging 2854 code in development but not in production. For example, it controls 2855 the behavior of the standard library's `debug_assert!` macro. 2856 2857 Note that this will apply to all Rust code, including `core`. 2858 2859 If unsure, say N. 2860 2861config RUST_OVERFLOW_CHECKS 2862 bool "Overflow checks" 2863 default y 2864 depends on RUST 2865 help 2866 Enables rustc's `-Coverflow-checks` codegen option. 2867 2868 This flag allows you to control the behavior of runtime integer 2869 overflow. When overflow-checks are enabled, a Rust panic will occur 2870 on overflow. 2871 2872 Note that this will apply to all Rust code, including `core`. 2873 2874 If unsure, say Y. 2875 2876config RUST_BUILD_ASSERT_ALLOW 2877 bool "Allow unoptimized build-time assertions" 2878 depends on RUST 2879 help 2880 Controls how are `build_error!` and `build_assert!` handled during build. 2881 2882 If calls to them exist in the binary, it may indicate a violated invariant 2883 or that the optimizer failed to verify the invariant during compilation. 2884 2885 This should not happen, thus by default the build is aborted. However, 2886 as an escape hatch, you can choose Y here to ignore them during build 2887 and let the check be carried at runtime (with `panic!` being called if 2888 the check fails). 2889 2890 If unsure, say N. 2891 2892endmenu # "Rust" 2893 2894source "Documentation/Kconfig" 2895 2896endmenu # Kernel hacking 2897