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 234choice 235 prompt "Debug information" 236 depends on DEBUG_KERNEL 237 help 238 Selecting something other than "None" results in a kernel image 239 that will include debugging info resulting in a larger kernel image. 240 This adds debug symbols to the kernel and modules (gcc -g), and 241 is needed if you intend to use kernel crashdump or binary object 242 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 243 244 Choose which version of DWARF debug info to emit. If unsure, 245 select "Toolchain default". 246 247config DEBUG_INFO_NONE 248 bool "Disable debug information" 249 help 250 Do not build the kernel with debugging information, which will 251 result in a faster and smaller build. 252 253config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 254 bool "Rely on the toolchain's implicit default DWARF version" 255 select DEBUG_INFO 256 help 257 The implicit default version of DWARF debug info produced by a 258 toolchain changes over time. 259 260 This can break consumers of the debug info that haven't upgraded to 261 support newer revisions, and prevent testing newer versions, but 262 those should be less common scenarios. 263 264config DEBUG_INFO_DWARF4 265 bool "Generate DWARF Version 4 debuginfo" 266 select DEBUG_INFO 267 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) 268 help 269 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2 270 if using clang without clang's integrated assembler, and gdb 7.0+. 271 272 If you have consumers of DWARF debug info that are not ready for 273 newer revisions of DWARF, you may wish to choose this or have your 274 config select this. 275 276config DEBUG_INFO_DWARF5 277 bool "Generate DWARF Version 5 debuginfo" 278 select DEBUG_INFO 279 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) 280 help 281 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 282 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 283 draft features until 7.0), and gdb 8.0+. 284 285 Changes to the structure of debug info in Version 5 allow for around 286 15-18% savings in resulting image and debug info section sizes as 287 compared to DWARF Version 4. DWARF Version 5 standardizes previous 288 extensions such as accelerators for symbol indexing and the format 289 for fission (.dwo/.dwp) files. Users may not want to select this 290 config if they rely on tooling that has not yet been updated to 291 support DWARF Version 5. 292 293endchoice # "Debug information" 294 295if DEBUG_INFO 296 297config DEBUG_INFO_REDUCED 298 bool "Reduce debugging information" 299 help 300 If you say Y here gcc is instructed to generate less debugging 301 information for structure types. This means that tools that 302 need full debugging information (like kgdb or systemtap) won't 303 be happy. But if you merely need debugging information to 304 resolve line numbers there is no loss. Advantage is that 305 build directory object sizes shrink dramatically over a full 306 DEBUG_INFO build and compile times are reduced too. 307 Only works with newer gcc versions. 308 309config DEBUG_INFO_COMPRESSED 310 bool "Compressed debugging information" 311 depends on $(cc-option,-gz=zlib) 312 depends on $(ld-option,--compress-debug-sections=zlib) 313 help 314 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 315 5.0+, binutils 2.26+, and zlib. 316 317 Users of dpkg-deb via scripts/package/builddeb may find an increase in 318 size of their debug .deb packages with this config set, due to the 319 debug info being compressed with zlib, then the object files being 320 recompressed with a different compression scheme. But this is still 321 preferable to setting $KDEB_COMPRESS to "none" which would be even 322 larger. 323 324config DEBUG_INFO_SPLIT 325 bool "Produce split debuginfo in .dwo files" 326 depends on $(cc-option,-gsplit-dwarf) 327 help 328 Generate debug info into separate .dwo files. This significantly 329 reduces the build directory size for builds with DEBUG_INFO, 330 because it stores the information only once on disk in .dwo 331 files instead of multiple times in object files and executables. 332 In addition the debug information is also compressed. 333 334 Requires recent gcc (4.7+) and recent gdb/binutils. 335 Any tool that packages or reads debug information would need 336 to know about the .dwo files and include them. 337 Incompatible with older versions of ccache. 338 339config DEBUG_INFO_BTF 340 bool "Generate BTF typeinfo" 341 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 342 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 343 depends on BPF_SYSCALL 344 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 345 help 346 Generate deduplicated BTF type information from DWARF debug info. 347 Turning this on expects presence of pahole tool, which will convert 348 DWARF type info into equivalent deduplicated BTF type info. 349 350config PAHOLE_HAS_SPLIT_BTF 351 def_bool PAHOLE_VERSION >= 119 352 353config PAHOLE_HAS_BTF_TAG 354 def_bool PAHOLE_VERSION >= 123 355 depends on CC_IS_CLANG 356 help 357 Decide whether pahole emits btf_tag attributes (btf_type_tag and 358 btf_decl_tag) or not. Currently only clang compiler implements 359 these attributes, so make the config depend on CC_IS_CLANG. 360 361config DEBUG_INFO_BTF_MODULES 362 def_bool y 363 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 364 help 365 Generate compact split BTF type information for kernel modules. 366 367config MODULE_ALLOW_BTF_MISMATCH 368 bool "Allow loading modules with non-matching BTF type info" 369 depends on DEBUG_INFO_BTF_MODULES 370 help 371 For modules whose split BTF does not match vmlinux, load without 372 BTF rather than refusing to load. The default behavior with 373 module BTF enabled is to reject modules with such mismatches; 374 this option will still load module BTF where possible but ignore 375 it when a mismatch is found. 376 377config GDB_SCRIPTS 378 bool "Provide GDB scripts for kernel debugging" 379 help 380 This creates the required links to GDB helper scripts in the 381 build directory. If you load vmlinux into gdb, the helper 382 scripts will be automatically imported by gdb as well, and 383 additional functions are available to analyze a Linux kernel 384 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 385 for further details. 386 387endif # DEBUG_INFO 388 389config FRAME_WARN 390 int "Warn for stack frames larger than" 391 range 0 8192 392 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 393 default 2048 if PARISC 394 default 1536 if (!64BIT && XTENSA) 395 default 1024 if !64BIT 396 default 2048 if 64BIT 397 help 398 Tell gcc to warn at build time for stack frames larger than this. 399 Setting this too low will cause a lot of warnings. 400 Setting it to 0 disables the warning. 401 402config STRIP_ASM_SYMS 403 bool "Strip assembler-generated symbols during link" 404 default n 405 help 406 Strip internal assembler-generated symbols during a link (symbols 407 that look like '.Lxxx') so they don't pollute the output of 408 get_wchan() and suchlike. 409 410config READABLE_ASM 411 bool "Generate readable assembler code" 412 depends on DEBUG_KERNEL 413 depends on CC_IS_GCC 414 help 415 Disable some compiler optimizations that tend to generate human unreadable 416 assembler output. This may make the kernel slightly slower, but it helps 417 to keep kernel developers who have to stare a lot at assembler listings 418 sane. 419 420config HEADERS_INSTALL 421 bool "Install uapi headers to usr/include" 422 depends on !UML 423 help 424 This option will install uapi headers (headers exported to user-space) 425 into the usr/include directory for use during the kernel build. 426 This is unneeded for building the kernel itself, but needed for some 427 user-space program samples. It is also needed by some features such 428 as uapi header sanity checks. 429 430config DEBUG_SECTION_MISMATCH 431 bool "Enable full Section mismatch analysis" 432 depends on CC_IS_GCC 433 help 434 The section mismatch analysis checks if there are illegal 435 references from one section to another section. 436 During linktime or runtime, some sections are dropped; 437 any use of code/data previously in these sections would 438 most likely result in an oops. 439 In the code, functions and variables are annotated with 440 __init,, etc. (see the full list in include/linux/init.h), 441 which results in the code/data being placed in specific sections. 442 The section mismatch analysis is always performed after a full 443 kernel build, and enabling this option causes the following 444 additional step to occur: 445 - Add the option -fno-inline-functions-called-once to gcc commands. 446 When inlining a function annotated with __init in a non-init 447 function, we would lose the section information and thus 448 the analysis would not catch the illegal reference. 449 This option tells gcc to inline less (but it does result in 450 a larger kernel). 451 452config SECTION_MISMATCH_WARN_ONLY 453 bool "Make section mismatch errors non-fatal" 454 default y 455 help 456 If you say N here, the build process will fail if there are any 457 section mismatch, instead of just throwing warnings. 458 459 If unsure, say Y. 460 461config DEBUG_FORCE_FUNCTION_ALIGN_64B 462 bool "Force all function address 64B aligned" 463 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 464 help 465 There are cases that a commit from one domain changes the function 466 address alignment of other domains, and cause magic performance 467 bump (regression or improvement). Enable this option will help to 468 verify if the bump is caused by function alignment changes, while 469 it will slightly increase the kernel size and affect icache usage. 470 471 It is mainly for debug and performance tuning use. 472 473# 474# Select this config option from the architecture Kconfig, if it 475# is preferred to always offer frame pointers as a config 476# option on the architecture (regardless of KERNEL_DEBUG): 477# 478config ARCH_WANT_FRAME_POINTERS 479 bool 480 481config FRAME_POINTER 482 bool "Compile the kernel with frame pointers" 483 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 484 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 485 help 486 If you say Y here the resulting kernel image will be slightly 487 larger and slower, but it gives very useful debugging information 488 in case of kernel bugs. (precise oopses/stacktraces/warnings) 489 490config OBJTOOL 491 bool 492 493config STACK_VALIDATION 494 bool "Compile-time stack metadata validation" 495 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 496 select OBJTOOL 497 default n 498 help 499 Validate frame pointer rules at compile-time. This helps ensure that 500 runtime stack traces are more reliable. 501 502 For more information, see 503 tools/objtool/Documentation/objtool.txt. 504 505config NOINSTR_VALIDATION 506 bool 507 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 508 select OBJTOOL 509 default y 510 511config VMLINUX_MAP 512 bool "Generate vmlinux.map file when linking" 513 depends on EXPERT 514 help 515 Selecting this option will pass "-Map=vmlinux.map" to ld 516 when linking vmlinux. That file can be useful for verifying 517 and debugging magic section games, and for seeing which 518 pieces of code get eliminated with 519 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 520 521config DEBUG_FORCE_WEAK_PER_CPU 522 bool "Force weak per-cpu definitions" 523 depends on DEBUG_KERNEL 524 help 525 s390 and alpha require percpu variables in modules to be 526 defined weak to work around addressing range issue which 527 puts the following two restrictions on percpu variable 528 definitions. 529 530 1. percpu symbols must be unique whether static or not 531 2. percpu variables can't be defined inside a function 532 533 To ensure that generic code follows the above rules, this 534 option forces all percpu variables to be defined as weak. 535 536endmenu # "Compiler options" 537 538menu "Generic Kernel Debugging Instruments" 539 540config MAGIC_SYSRQ 541 bool "Magic SysRq key" 542 depends on !UML 543 help 544 If you say Y here, you will have some control over the system even 545 if the system crashes for example during kernel debugging (e.g., you 546 will be able to flush the buffer cache to disk, reboot the system 547 immediately or dump some status information). This is accomplished 548 by pressing various keys while holding SysRq (Alt+PrintScreen). It 549 also works on a serial console (on PC hardware at least), if you 550 send a BREAK and then within 5 seconds a command keypress. The 551 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 552 Don't say Y unless you really know what this hack does. 553 554config MAGIC_SYSRQ_DEFAULT_ENABLE 555 hex "Enable magic SysRq key functions by default" 556 depends on MAGIC_SYSRQ 557 default 0x1 558 help 559 Specifies which SysRq key functions are enabled by default. 560 This may be set to 1 or 0 to enable or disable them all, or 561 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 562 563config MAGIC_SYSRQ_SERIAL 564 bool "Enable magic SysRq key over serial" 565 depends on MAGIC_SYSRQ 566 default y 567 help 568 Many embedded boards have a disconnected TTL level serial which can 569 generate some garbage that can lead to spurious false sysrq detects. 570 This option allows you to decide whether you want to enable the 571 magic SysRq key. 572 573config MAGIC_SYSRQ_SERIAL_SEQUENCE 574 string "Char sequence that enables magic SysRq over serial" 575 depends on MAGIC_SYSRQ_SERIAL 576 default "" 577 help 578 Specifies a sequence of characters that can follow BREAK to enable 579 SysRq on a serial console. 580 581 If unsure, leave an empty string and the option will not be enabled. 582 583config DEBUG_FS 584 bool "Debug Filesystem" 585 help 586 debugfs is a virtual file system that kernel developers use to put 587 debugging files into. Enable this option to be able to read and 588 write to these files. 589 590 For detailed documentation on the debugfs API, see 591 Documentation/filesystems/. 592 593 If unsure, say N. 594 595choice 596 prompt "Debugfs default access" 597 depends on DEBUG_FS 598 default DEBUG_FS_ALLOW_ALL 599 help 600 This selects the default access restrictions for debugfs. 601 It can be overridden with kernel command line option 602 debugfs=[on,no-mount,off]. The restrictions apply for API access 603 and filesystem registration. 604 605config DEBUG_FS_ALLOW_ALL 606 bool "Access normal" 607 help 608 No restrictions apply. Both API and filesystem registration 609 is on. This is the normal default operation. 610 611config DEBUG_FS_DISALLOW_MOUNT 612 bool "Do not register debugfs as filesystem" 613 help 614 The API is open but filesystem is not loaded. Clients can still do 615 their work and read with debug tools that do not need 616 debugfs filesystem. 617 618config DEBUG_FS_ALLOW_NONE 619 bool "No access" 620 help 621 Access is off. Clients get -PERM when trying to create nodes in 622 debugfs tree and debugfs is not registered as a filesystem. 623 Client can then back-off or continue without debugfs access. 624 625endchoice 626 627source "lib/Kconfig.kgdb" 628source "lib/Kconfig.ubsan" 629source "lib/Kconfig.kcsan" 630 631endmenu 632 633menu "Networking Debugging" 634 635source "net/Kconfig.debug" 636 637endmenu # "Networking Debugging" 638 639menu "Memory Debugging" 640 641source "mm/Kconfig.debug" 642 643config DEBUG_OBJECTS 644 bool "Debug object operations" 645 depends on DEBUG_KERNEL 646 help 647 If you say Y here, additional code will be inserted into the 648 kernel to track the life time of various objects and validate 649 the operations on those objects. 650 651config DEBUG_OBJECTS_SELFTEST 652 bool "Debug objects selftest" 653 depends on DEBUG_OBJECTS 654 help 655 This enables the selftest of the object debug code. 656 657config DEBUG_OBJECTS_FREE 658 bool "Debug objects in freed memory" 659 depends on DEBUG_OBJECTS 660 help 661 This enables checks whether a k/v free operation frees an area 662 which contains an object which has not been deactivated 663 properly. This can make kmalloc/kfree-intensive workloads 664 much slower. 665 666config DEBUG_OBJECTS_TIMERS 667 bool "Debug timer objects" 668 depends on DEBUG_OBJECTS 669 help 670 If you say Y here, additional code will be inserted into the 671 timer routines to track the life time of timer objects and 672 validate the timer operations. 673 674config DEBUG_OBJECTS_WORK 675 bool "Debug work objects" 676 depends on DEBUG_OBJECTS 677 help 678 If you say Y here, additional code will be inserted into the 679 work queue routines to track the life time of work objects and 680 validate the work operations. 681 682config DEBUG_OBJECTS_RCU_HEAD 683 bool "Debug RCU callbacks objects" 684 depends on DEBUG_OBJECTS 685 help 686 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 687 688config DEBUG_OBJECTS_PERCPU_COUNTER 689 bool "Debug percpu counter objects" 690 depends on DEBUG_OBJECTS 691 help 692 If you say Y here, additional code will be inserted into the 693 percpu counter routines to track the life time of percpu counter 694 objects and validate the percpu counter operations. 695 696config DEBUG_OBJECTS_ENABLE_DEFAULT 697 int "debug_objects bootup default value (0-1)" 698 range 0 1 699 default "1" 700 depends on DEBUG_OBJECTS 701 help 702 Debug objects boot parameter default value 703 704config SHRINKER_DEBUG 705 bool "Enable shrinker debugging support" 706 depends on DEBUG_FS 707 help 708 Say Y to enable the shrinker debugfs interface which provides 709 visibility into the kernel memory shrinkers subsystem. 710 Disable it to avoid an extra memory footprint. 711 712config HAVE_DEBUG_KMEMLEAK 713 bool 714 715config DEBUG_KMEMLEAK 716 bool "Kernel memory leak detector" 717 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 718 select DEBUG_FS 719 select STACKTRACE if STACKTRACE_SUPPORT 720 select KALLSYMS 721 select CRC32 722 help 723 Say Y here if you want to enable the memory leak 724 detector. The memory allocation/freeing is traced in a way 725 similar to the Boehm's conservative garbage collector, the 726 difference being that the orphan objects are not freed but 727 only shown in /sys/kernel/debug/kmemleak. Enabling this 728 feature will introduce an overhead to memory 729 allocations. See Documentation/dev-tools/kmemleak.rst for more 730 details. 731 732 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 733 of finding leaks due to the slab objects poisoning. 734 735 In order to access the kmemleak file, debugfs needs to be 736 mounted (usually at /sys/kernel/debug). 737 738config DEBUG_KMEMLEAK_MEM_POOL_SIZE 739 int "Kmemleak memory pool size" 740 depends on DEBUG_KMEMLEAK 741 range 200 1000000 742 default 16000 743 help 744 Kmemleak must track all the memory allocations to avoid 745 reporting false positives. Since memory may be allocated or 746 freed before kmemleak is fully initialised, use a static pool 747 of metadata objects to track such callbacks. After kmemleak is 748 fully initialised, this memory pool acts as an emergency one 749 if slab allocations fail. 750 751config DEBUG_KMEMLEAK_TEST 752 tristate "Simple test for the kernel memory leak detector" 753 depends on DEBUG_KMEMLEAK && m 754 help 755 This option enables a module that explicitly leaks memory. 756 757 If unsure, say N. 758 759config DEBUG_KMEMLEAK_DEFAULT_OFF 760 bool "Default kmemleak to off" 761 depends on DEBUG_KMEMLEAK 762 help 763 Say Y here to disable kmemleak by default. It can then be enabled 764 on the command line via kmemleak=on. 765 766config DEBUG_KMEMLEAK_AUTO_SCAN 767 bool "Enable kmemleak auto scan thread on boot up" 768 default y 769 depends on DEBUG_KMEMLEAK 770 help 771 Depending on the cpu, kmemleak scan may be cpu intensive and can 772 stall user tasks at times. This option enables/disables automatic 773 kmemleak scan at boot up. 774 775 Say N here to disable kmemleak auto scan thread to stop automatic 776 scanning. Disabling this option disables automatic reporting of 777 memory leaks. 778 779 If unsure, say Y. 780 781config DEBUG_STACK_USAGE 782 bool "Stack utilization instrumentation" 783 depends on DEBUG_KERNEL && !IA64 784 help 785 Enables the display of the minimum amount of free stack which each 786 task has ever had available in the sysrq-T and sysrq-P debug output. 787 788 This option will slow down process creation somewhat. 789 790config SCHED_STACK_END_CHECK 791 bool "Detect stack corruption on calls to schedule()" 792 depends on DEBUG_KERNEL 793 default n 794 help 795 This option checks for a stack overrun on calls to schedule(). 796 If the stack end location is found to be over written always panic as 797 the content of the corrupted region can no longer be trusted. 798 This is to ensure no erroneous behaviour occurs which could result in 799 data corruption or a sporadic crash at a later stage once the region 800 is examined. The runtime overhead introduced is minimal. 801 802config ARCH_HAS_DEBUG_VM_PGTABLE 803 bool 804 help 805 An architecture should select this when it can successfully 806 build and run DEBUG_VM_PGTABLE. 807 808config DEBUG_VM 809 bool "Debug VM" 810 depends on DEBUG_KERNEL 811 help 812 Enable this to turn on extended checks in the virtual-memory system 813 that may impact performance. 814 815 If unsure, say N. 816 817config DEBUG_VM_VMACACHE 818 bool "Debug VMA caching" 819 depends on DEBUG_VM 820 help 821 Enable this to turn on VMA caching debug information. Doing so 822 can cause significant overhead, so only enable it in non-production 823 environments. 824 825 If unsure, say N. 826 827config DEBUG_VM_RB 828 bool "Debug VM red-black trees" 829 depends on DEBUG_VM 830 help 831 Enable VM red-black tree debugging information and extra validations. 832 833 If unsure, say N. 834 835config DEBUG_VM_PGFLAGS 836 bool "Debug page-flags operations" 837 depends on DEBUG_VM 838 help 839 Enables extra validation on page flags operations. 840 841 If unsure, say N. 842 843config DEBUG_VM_PGTABLE 844 bool "Debug arch page table for semantics compliance" 845 depends on MMU 846 depends on ARCH_HAS_DEBUG_VM_PGTABLE 847 default y if DEBUG_VM 848 help 849 This option provides a debug method which can be used to test 850 architecture page table helper functions on various platforms in 851 verifying if they comply with expected generic MM semantics. This 852 will help architecture code in making sure that any changes or 853 new additions of these helpers still conform to expected 854 semantics of the generic MM. Platforms will have to opt in for 855 this through ARCH_HAS_DEBUG_VM_PGTABLE. 856 857 If unsure, say N. 858 859config ARCH_HAS_DEBUG_VIRTUAL 860 bool 861 862config DEBUG_VIRTUAL 863 bool "Debug VM translations" 864 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 865 help 866 Enable some costly sanity checks in virtual to page code. This can 867 catch mistakes with virt_to_page() and friends. 868 869 If unsure, say N. 870 871config DEBUG_NOMMU_REGIONS 872 bool "Debug the global anon/private NOMMU mapping region tree" 873 depends on DEBUG_KERNEL && !MMU 874 help 875 This option causes the global tree of anonymous and private mapping 876 regions to be regularly checked for invalid topology. 877 878config DEBUG_MEMORY_INIT 879 bool "Debug memory initialisation" if EXPERT 880 default !EXPERT 881 help 882 Enable this for additional checks during memory initialisation. 883 The sanity checks verify aspects of the VM such as the memory model 884 and other information provided by the architecture. Verbose 885 information will be printed at KERN_DEBUG loglevel depending 886 on the mminit_loglevel= command-line option. 887 888 If unsure, say Y 889 890config MEMORY_NOTIFIER_ERROR_INJECT 891 tristate "Memory hotplug notifier error injection module" 892 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 893 help 894 This option provides the ability to inject artificial errors to 895 memory hotplug notifier chain callbacks. It is controlled through 896 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 897 898 If the notifier call chain should be failed with some events 899 notified, write the error code to "actions/<notifier event>/error". 900 901 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 902 903 # cd /sys/kernel/debug/notifier-error-inject/memory 904 # echo -12 > actions/MEM_GOING_OFFLINE/error 905 # echo offline > /sys/devices/system/memory/memoryXXX/state 906 bash: echo: write error: Cannot allocate memory 907 908 To compile this code as a module, choose M here: the module will 909 be called memory-notifier-error-inject. 910 911 If unsure, say N. 912 913config DEBUG_PER_CPU_MAPS 914 bool "Debug access to per_cpu maps" 915 depends on DEBUG_KERNEL 916 depends on SMP 917 help 918 Say Y to verify that the per_cpu map being accessed has 919 been set up. This adds a fair amount of code to kernel memory 920 and decreases performance. 921 922 Say N if unsure. 923 924config DEBUG_KMAP_LOCAL 925 bool "Debug kmap_local temporary mappings" 926 depends on DEBUG_KERNEL && KMAP_LOCAL 927 help 928 This option enables additional error checking for the kmap_local 929 infrastructure. Disable for production use. 930 931config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 932 bool 933 934config DEBUG_KMAP_LOCAL_FORCE_MAP 935 bool "Enforce kmap_local temporary mappings" 936 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 937 select KMAP_LOCAL 938 select DEBUG_KMAP_LOCAL 939 help 940 This option enforces temporary mappings through the kmap_local 941 mechanism for non-highmem pages and on non-highmem systems. 942 Disable this for production systems! 943 944config DEBUG_HIGHMEM 945 bool "Highmem debugging" 946 depends on DEBUG_KERNEL && HIGHMEM 947 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 948 select DEBUG_KMAP_LOCAL 949 help 950 This option enables additional error checking for high memory 951 systems. Disable for production systems. 952 953config HAVE_DEBUG_STACKOVERFLOW 954 bool 955 956config DEBUG_STACKOVERFLOW 957 bool "Check for stack overflows" 958 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 959 help 960 Say Y here if you want to check for overflows of kernel, IRQ 961 and exception stacks (if your architecture uses them). This 962 option will show detailed messages if free stack space drops 963 below a certain limit. 964 965 These kinds of bugs usually occur when call-chains in the 966 kernel get too deep, especially when interrupts are 967 involved. 968 969 Use this in cases where you see apparently random memory 970 corruption, especially if it appears in 'struct thread_info' 971 972 If in doubt, say "N". 973 974source "lib/Kconfig.kasan" 975source "lib/Kconfig.kfence" 976 977endmenu # "Memory Debugging" 978 979config DEBUG_SHIRQ 980 bool "Debug shared IRQ handlers" 981 depends on DEBUG_KERNEL 982 help 983 Enable this to generate a spurious interrupt just before a shared 984 interrupt handler is deregistered (generating one when registering 985 is currently disabled). Drivers need to handle this correctly. Some 986 don't and need to be caught. 987 988menu "Debug Oops, Lockups and Hangs" 989 990config PANIC_ON_OOPS 991 bool "Panic on Oops" 992 help 993 Say Y here to enable the kernel to panic when it oopses. This 994 has the same effect as setting oops=panic on the kernel command 995 line. 996 997 This feature is useful to ensure that the kernel does not do 998 anything erroneous after an oops which could result in data 999 corruption or other issues. 1000 1001 Say N if unsure. 1002 1003config PANIC_ON_OOPS_VALUE 1004 int 1005 range 0 1 1006 default 0 if !PANIC_ON_OOPS 1007 default 1 if PANIC_ON_OOPS 1008 1009config PANIC_TIMEOUT 1010 int "panic timeout" 1011 default 0 1012 help 1013 Set the timeout value (in seconds) until a reboot occurs when 1014 the kernel panics. If n = 0, then we wait forever. A timeout 1015 value n > 0 will wait n seconds before rebooting, while a timeout 1016 value n < 0 will reboot immediately. 1017 1018config LOCKUP_DETECTOR 1019 bool 1020 1021config SOFTLOCKUP_DETECTOR 1022 bool "Detect Soft Lockups" 1023 depends on DEBUG_KERNEL && !S390 1024 select LOCKUP_DETECTOR 1025 help 1026 Say Y here to enable the kernel to act as a watchdog to detect 1027 soft lockups. 1028 1029 Softlockups are bugs that cause the kernel to loop in kernel 1030 mode for more than 20 seconds, without giving other tasks a 1031 chance to run. The current stack trace is displayed upon 1032 detection and the system will stay locked up. 1033 1034config BOOTPARAM_SOFTLOCKUP_PANIC 1035 bool "Panic (Reboot) On Soft Lockups" 1036 depends on SOFTLOCKUP_DETECTOR 1037 help 1038 Say Y here to enable the kernel to panic on "soft lockups", 1039 which are bugs that cause the kernel to loop in kernel 1040 mode for more than 20 seconds (configurable using the watchdog_thresh 1041 sysctl), without giving other tasks a chance to run. 1042 1043 The panic can be used in combination with panic_timeout, 1044 to cause the system to reboot automatically after a 1045 lockup has been detected. This feature is useful for 1046 high-availability systems that have uptime guarantees and 1047 where a lockup must be resolved ASAP. 1048 1049 Say N if unsure. 1050 1051config HARDLOCKUP_DETECTOR_PERF 1052 bool 1053 select SOFTLOCKUP_DETECTOR 1054 1055# 1056# Enables a timestamp based low pass filter to compensate for perf based 1057# hard lockup detection which runs too fast due to turbo modes. 1058# 1059config HARDLOCKUP_CHECK_TIMESTAMP 1060 bool 1061 1062# 1063# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1064# lockup detector rather than the perf based detector. 1065# 1066config HARDLOCKUP_DETECTOR 1067 bool "Detect Hard Lockups" 1068 depends on DEBUG_KERNEL && !S390 1069 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1070 select LOCKUP_DETECTOR 1071 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1072 help 1073 Say Y here to enable the kernel to act as a watchdog to detect 1074 hard lockups. 1075 1076 Hardlockups are bugs that cause the CPU to loop in kernel mode 1077 for more than 10 seconds, without letting other interrupts have a 1078 chance to run. The current stack trace is displayed upon detection 1079 and the system will stay locked up. 1080 1081config BOOTPARAM_HARDLOCKUP_PANIC 1082 bool "Panic (Reboot) On Hard Lockups" 1083 depends on HARDLOCKUP_DETECTOR 1084 help 1085 Say Y here to enable the kernel to panic on "hard lockups", 1086 which are bugs that cause the kernel to loop in kernel 1087 mode with interrupts disabled for more than 10 seconds (configurable 1088 using the watchdog_thresh sysctl). 1089 1090 Say N if unsure. 1091 1092config DETECT_HUNG_TASK 1093 bool "Detect Hung Tasks" 1094 depends on DEBUG_KERNEL 1095 default SOFTLOCKUP_DETECTOR 1096 help 1097 Say Y here to enable the kernel to detect "hung tasks", 1098 which are bugs that cause the task to be stuck in 1099 uninterruptible "D" state indefinitely. 1100 1101 When a hung task is detected, the kernel will print the 1102 current stack trace (which you should report), but the 1103 task will stay in uninterruptible state. If lockdep is 1104 enabled then all held locks will also be reported. This 1105 feature has negligible overhead. 1106 1107config DEFAULT_HUNG_TASK_TIMEOUT 1108 int "Default timeout for hung task detection (in seconds)" 1109 depends on DETECT_HUNG_TASK 1110 default 120 1111 help 1112 This option controls the default timeout (in seconds) used 1113 to determine when a task has become non-responsive and should 1114 be considered hung. 1115 1116 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1117 sysctl or by writing a value to 1118 /proc/sys/kernel/hung_task_timeout_secs. 1119 1120 A timeout of 0 disables the check. The default is two minutes. 1121 Keeping the default should be fine in most cases. 1122 1123config BOOTPARAM_HUNG_TASK_PANIC 1124 bool "Panic (Reboot) On Hung Tasks" 1125 depends on DETECT_HUNG_TASK 1126 help 1127 Say Y here to enable the kernel to panic on "hung tasks", 1128 which are bugs that cause the kernel to leave a task stuck 1129 in uninterruptible "D" state. 1130 1131 The panic can be used in combination with panic_timeout, 1132 to cause the system to reboot automatically after a 1133 hung task has been detected. This feature is useful for 1134 high-availability systems that have uptime guarantees and 1135 where a hung tasks must be resolved ASAP. 1136 1137 Say N if unsure. 1138 1139config WQ_WATCHDOG 1140 bool "Detect Workqueue Stalls" 1141 depends on DEBUG_KERNEL 1142 help 1143 Say Y here to enable stall detection on workqueues. If a 1144 worker pool doesn't make forward progress on a pending work 1145 item for over a given amount of time, 30s by default, a 1146 warning message is printed along with dump of workqueue 1147 state. This can be configured through kernel parameter 1148 "workqueue.watchdog_thresh" and its sysfs counterpart. 1149 1150config TEST_LOCKUP 1151 tristate "Test module to generate lockups" 1152 depends on m 1153 help 1154 This builds the "test_lockup" module that helps to make sure 1155 that watchdogs and lockup detectors are working properly. 1156 1157 Depending on module parameters it could emulate soft or hard 1158 lockup, "hung task", or locking arbitrary lock for a long time. 1159 Also it could generate series of lockups with cooling-down periods. 1160 1161 If unsure, say N. 1162 1163endmenu # "Debug lockups and hangs" 1164 1165menu "Scheduler Debugging" 1166 1167config SCHED_DEBUG 1168 bool "Collect scheduler debugging info" 1169 depends on DEBUG_KERNEL && PROC_FS 1170 default y 1171 help 1172 If you say Y here, the /proc/sched_debug file will be provided 1173 that can help debug the scheduler. The runtime overhead of this 1174 option is minimal. 1175 1176config SCHED_INFO 1177 bool 1178 default n 1179 1180config SCHEDSTATS 1181 bool "Collect scheduler statistics" 1182 depends on DEBUG_KERNEL && PROC_FS 1183 select SCHED_INFO 1184 help 1185 If you say Y here, additional code will be inserted into the 1186 scheduler and related routines to collect statistics about 1187 scheduler behavior and provide them in /proc/schedstat. These 1188 stats may be useful for both tuning and debugging the scheduler 1189 If you aren't debugging the scheduler or trying to tune a specific 1190 application, you can say N to avoid the very slight overhead 1191 this adds. 1192 1193endmenu 1194 1195config DEBUG_TIMEKEEPING 1196 bool "Enable extra timekeeping sanity checking" 1197 help 1198 This option will enable additional timekeeping sanity checks 1199 which may be helpful when diagnosing issues where timekeeping 1200 problems are suspected. 1201 1202 This may include checks in the timekeeping hotpaths, so this 1203 option may have a (very small) performance impact to some 1204 workloads. 1205 1206 If unsure, say N. 1207 1208config DEBUG_PREEMPT 1209 bool "Debug preemptible kernel" 1210 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1211 default y 1212 help 1213 If you say Y here then the kernel will use a debug variant of the 1214 commonly used smp_processor_id() function and will print warnings 1215 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1216 will detect preemption count underflows. 1217 1218menu "Lock Debugging (spinlocks, mutexes, etc...)" 1219 1220config LOCK_DEBUGGING_SUPPORT 1221 bool 1222 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1223 default y 1224 1225config PROVE_LOCKING 1226 bool "Lock debugging: prove locking correctness" 1227 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1228 select LOCKDEP 1229 select DEBUG_SPINLOCK 1230 select DEBUG_MUTEXES if !PREEMPT_RT 1231 select DEBUG_RT_MUTEXES if RT_MUTEXES 1232 select DEBUG_RWSEMS 1233 select DEBUG_WW_MUTEX_SLOWPATH 1234 select DEBUG_LOCK_ALLOC 1235 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1236 select TRACE_IRQFLAGS 1237 default n 1238 help 1239 This feature enables the kernel to prove that all locking 1240 that occurs in the kernel runtime is mathematically 1241 correct: that under no circumstance could an arbitrary (and 1242 not yet triggered) combination of observed locking 1243 sequences (on an arbitrary number of CPUs, running an 1244 arbitrary number of tasks and interrupt contexts) cause a 1245 deadlock. 1246 1247 In short, this feature enables the kernel to report locking 1248 related deadlocks before they actually occur. 1249 1250 The proof does not depend on how hard and complex a 1251 deadlock scenario would be to trigger: how many 1252 participant CPUs, tasks and irq-contexts would be needed 1253 for it to trigger. The proof also does not depend on 1254 timing: if a race and a resulting deadlock is possible 1255 theoretically (no matter how unlikely the race scenario 1256 is), it will be proven so and will immediately be 1257 reported by the kernel (once the event is observed that 1258 makes the deadlock theoretically possible). 1259 1260 If a deadlock is impossible (i.e. the locking rules, as 1261 observed by the kernel, are mathematically correct), the 1262 kernel reports nothing. 1263 1264 NOTE: this feature can also be enabled for rwlocks, mutexes 1265 and rwsems - in which case all dependencies between these 1266 different locking variants are observed and mapped too, and 1267 the proof of observed correctness is also maintained for an 1268 arbitrary combination of these separate locking variants. 1269 1270 For more details, see Documentation/locking/lockdep-design.rst. 1271 1272config PROVE_RAW_LOCK_NESTING 1273 bool "Enable raw_spinlock - spinlock nesting checks" 1274 depends on PROVE_LOCKING 1275 default n 1276 help 1277 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1278 that the lock nesting rules for PREEMPT_RT enabled kernels are 1279 not violated. 1280 1281 NOTE: There are known nesting problems. So if you enable this 1282 option expect lockdep splats until these problems have been fully 1283 addressed which is work in progress. This config switch allows to 1284 identify and analyze these problems. It will be removed and the 1285 check permanently enabled once the main issues have been fixed. 1286 1287 If unsure, select N. 1288 1289config LOCK_STAT 1290 bool "Lock usage statistics" 1291 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1292 select LOCKDEP 1293 select DEBUG_SPINLOCK 1294 select DEBUG_MUTEXES if !PREEMPT_RT 1295 select DEBUG_RT_MUTEXES if RT_MUTEXES 1296 select DEBUG_LOCK_ALLOC 1297 default n 1298 help 1299 This feature enables tracking lock contention points 1300 1301 For more details, see Documentation/locking/lockstat.rst 1302 1303 This also enables lock events required by "perf lock", 1304 subcommand of perf. 1305 If you want to use "perf lock", you also need to turn on 1306 CONFIG_EVENT_TRACING. 1307 1308 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1309 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1310 1311config DEBUG_RT_MUTEXES 1312 bool "RT Mutex debugging, deadlock detection" 1313 depends on DEBUG_KERNEL && RT_MUTEXES 1314 help 1315 This allows rt mutex semantics violations and rt mutex related 1316 deadlocks (lockups) to be detected and reported automatically. 1317 1318config DEBUG_SPINLOCK 1319 bool "Spinlock and rw-lock debugging: basic checks" 1320 depends on DEBUG_KERNEL 1321 select UNINLINE_SPIN_UNLOCK 1322 help 1323 Say Y here and build SMP to catch missing spinlock initialization 1324 and certain other kinds of spinlock errors commonly made. This is 1325 best used in conjunction with the NMI watchdog so that spinlock 1326 deadlocks are also debuggable. 1327 1328config DEBUG_MUTEXES 1329 bool "Mutex debugging: basic checks" 1330 depends on DEBUG_KERNEL && !PREEMPT_RT 1331 help 1332 This feature allows mutex semantics violations to be detected and 1333 reported. 1334 1335config DEBUG_WW_MUTEX_SLOWPATH 1336 bool "Wait/wound mutex debugging: Slowpath testing" 1337 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1338 select DEBUG_LOCK_ALLOC 1339 select DEBUG_SPINLOCK 1340 select DEBUG_MUTEXES if !PREEMPT_RT 1341 select DEBUG_RT_MUTEXES if PREEMPT_RT 1342 help 1343 This feature enables slowpath testing for w/w mutex users by 1344 injecting additional -EDEADLK wound/backoff cases. Together with 1345 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1346 will test all possible w/w mutex interface abuse with the 1347 exception of simply not acquiring all the required locks. 1348 Note that this feature can introduce significant overhead, so 1349 it really should not be enabled in a production or distro kernel, 1350 even a debug kernel. If you are a driver writer, enable it. If 1351 you are a distro, do not. 1352 1353config DEBUG_RWSEMS 1354 bool "RW Semaphore debugging: basic checks" 1355 depends on DEBUG_KERNEL 1356 help 1357 This debugging feature allows mismatched rw semaphore locks 1358 and unlocks to be detected and reported. 1359 1360config DEBUG_LOCK_ALLOC 1361 bool "Lock debugging: detect incorrect freeing of live locks" 1362 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1363 select DEBUG_SPINLOCK 1364 select DEBUG_MUTEXES if !PREEMPT_RT 1365 select DEBUG_RT_MUTEXES if RT_MUTEXES 1366 select LOCKDEP 1367 help 1368 This feature will check whether any held lock (spinlock, rwlock, 1369 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1370 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1371 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1372 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1373 held during task exit. 1374 1375config LOCKDEP 1376 bool 1377 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1378 select STACKTRACE 1379 select KALLSYMS 1380 select KALLSYMS_ALL 1381 1382config LOCKDEP_SMALL 1383 bool 1384 1385config LOCKDEP_BITS 1386 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1387 depends on LOCKDEP && !LOCKDEP_SMALL 1388 range 10 30 1389 default 15 1390 help 1391 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1392 1393config LOCKDEP_CHAINS_BITS 1394 int "Bitsize for MAX_LOCKDEP_CHAINS" 1395 depends on LOCKDEP && !LOCKDEP_SMALL 1396 range 10 30 1397 default 16 1398 help 1399 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1400 1401config LOCKDEP_STACK_TRACE_BITS 1402 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1403 depends on LOCKDEP && !LOCKDEP_SMALL 1404 range 10 30 1405 default 19 1406 help 1407 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1408 1409config LOCKDEP_STACK_TRACE_HASH_BITS 1410 int "Bitsize for STACK_TRACE_HASH_SIZE" 1411 depends on LOCKDEP && !LOCKDEP_SMALL 1412 range 10 30 1413 default 14 1414 help 1415 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1416 1417config LOCKDEP_CIRCULAR_QUEUE_BITS 1418 int "Bitsize for elements in circular_queue struct" 1419 depends on LOCKDEP 1420 range 10 30 1421 default 12 1422 help 1423 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1424 1425config DEBUG_LOCKDEP 1426 bool "Lock dependency engine debugging" 1427 depends on DEBUG_KERNEL && LOCKDEP 1428 select DEBUG_IRQFLAGS 1429 help 1430 If you say Y here, the lock dependency engine will do 1431 additional runtime checks to debug itself, at the price 1432 of more runtime overhead. 1433 1434config DEBUG_ATOMIC_SLEEP 1435 bool "Sleep inside atomic section checking" 1436 select PREEMPT_COUNT 1437 depends on DEBUG_KERNEL 1438 depends on !ARCH_NO_PREEMPT 1439 help 1440 If you say Y here, various routines which may sleep will become very 1441 noisy if they are called inside atomic sections: when a spinlock is 1442 held, inside an rcu read side critical section, inside preempt disabled 1443 sections, inside an interrupt, etc... 1444 1445config DEBUG_LOCKING_API_SELFTESTS 1446 bool "Locking API boot-time self-tests" 1447 depends on DEBUG_KERNEL 1448 help 1449 Say Y here if you want the kernel to run a short self-test during 1450 bootup. The self-test checks whether common types of locking bugs 1451 are detected by debugging mechanisms or not. (if you disable 1452 lock debugging then those bugs won't be detected of course.) 1453 The following locking APIs are covered: spinlocks, rwlocks, 1454 mutexes and rwsems. 1455 1456config LOCK_TORTURE_TEST 1457 tristate "torture tests for locking" 1458 depends on DEBUG_KERNEL 1459 select TORTURE_TEST 1460 help 1461 This option provides a kernel module that runs torture tests 1462 on kernel locking primitives. The kernel module may be built 1463 after the fact on the running kernel to be tested, if desired. 1464 1465 Say Y here if you want kernel locking-primitive torture tests 1466 to be built into the kernel. 1467 Say M if you want these torture tests to build as a module. 1468 Say N if you are unsure. 1469 1470config WW_MUTEX_SELFTEST 1471 tristate "Wait/wound mutex selftests" 1472 help 1473 This option provides a kernel module that runs tests on the 1474 on the struct ww_mutex locking API. 1475 1476 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1477 with this test harness. 1478 1479 Say M if you want these self tests to build as a module. 1480 Say N if you are unsure. 1481 1482config SCF_TORTURE_TEST 1483 tristate "torture tests for smp_call_function*()" 1484 depends on DEBUG_KERNEL 1485 select TORTURE_TEST 1486 help 1487 This option provides a kernel module that runs torture tests 1488 on the smp_call_function() family of primitives. The kernel 1489 module may be built after the fact on the running kernel to 1490 be tested, if desired. 1491 1492config CSD_LOCK_WAIT_DEBUG 1493 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1494 depends on DEBUG_KERNEL 1495 depends on 64BIT 1496 default n 1497 help 1498 This option enables debug prints when CPUs are slow to respond 1499 to the smp_call_function*() IPI wrappers. These debug prints 1500 include the IPI handler function currently executing (if any) 1501 and relevant stack traces. 1502 1503endmenu # lock debugging 1504 1505config TRACE_IRQFLAGS 1506 depends on TRACE_IRQFLAGS_SUPPORT 1507 bool 1508 help 1509 Enables hooks to interrupt enabling and disabling for 1510 either tracing or lock debugging. 1511 1512config TRACE_IRQFLAGS_NMI 1513 def_bool y 1514 depends on TRACE_IRQFLAGS 1515 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1516 1517config DEBUG_IRQFLAGS 1518 bool "Debug IRQ flag manipulation" 1519 help 1520 Enables checks for potentially unsafe enabling or disabling of 1521 interrupts, such as calling raw_local_irq_restore() when interrupts 1522 are enabled. 1523 1524config STACKTRACE 1525 bool "Stack backtrace support" 1526 depends on STACKTRACE_SUPPORT 1527 help 1528 This option causes the kernel to create a /proc/pid/stack for 1529 every process, showing its current stack trace. 1530 It is also used by various kernel debugging features that require 1531 stack trace generation. 1532 1533config WARN_ALL_UNSEEDED_RANDOM 1534 bool "Warn for all uses of unseeded randomness" 1535 default n 1536 help 1537 Some parts of the kernel contain bugs relating to their use of 1538 cryptographically secure random numbers before it's actually possible 1539 to generate those numbers securely. This setting ensures that these 1540 flaws don't go unnoticed, by enabling a message, should this ever 1541 occur. This will allow people with obscure setups to know when things 1542 are going wrong, so that they might contact developers about fixing 1543 it. 1544 1545 Unfortunately, on some models of some architectures getting 1546 a fully seeded CRNG is extremely difficult, and so this can 1547 result in dmesg getting spammed for a surprisingly long 1548 time. This is really bad from a security perspective, and 1549 so architecture maintainers really need to do what they can 1550 to get the CRNG seeded sooner after the system is booted. 1551 However, since users cannot do anything actionable to 1552 address this, by default this option is disabled. 1553 1554 Say Y here if you want to receive warnings for all uses of 1555 unseeded randomness. This will be of use primarily for 1556 those developers interested in improving the security of 1557 Linux kernels running on their architecture (or 1558 subarchitecture). 1559 1560config DEBUG_KOBJECT 1561 bool "kobject debugging" 1562 depends on DEBUG_KERNEL 1563 help 1564 If you say Y here, some extra kobject debugging messages will be sent 1565 to the syslog. 1566 1567config DEBUG_KOBJECT_RELEASE 1568 bool "kobject release debugging" 1569 depends on DEBUG_OBJECTS_TIMERS 1570 help 1571 kobjects are reference counted objects. This means that their 1572 last reference count put is not predictable, and the kobject can 1573 live on past the point at which a driver decides to drop its 1574 initial reference to the kobject gained on allocation. An 1575 example of this would be a struct device which has just been 1576 unregistered. 1577 1578 However, some buggy drivers assume that after such an operation, 1579 the memory backing the kobject can be immediately freed. This 1580 goes completely against the principles of a refcounted object. 1581 1582 If you say Y here, the kernel will delay the release of kobjects 1583 on the last reference count to improve the visibility of this 1584 kind of kobject release bug. 1585 1586config HAVE_DEBUG_BUGVERBOSE 1587 bool 1588 1589menu "Debug kernel data structures" 1590 1591config DEBUG_LIST 1592 bool "Debug linked list manipulation" 1593 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1594 help 1595 Enable this to turn on extended checks in the linked-list 1596 walking routines. 1597 1598 If unsure, say N. 1599 1600config DEBUG_PLIST 1601 bool "Debug priority linked list manipulation" 1602 depends on DEBUG_KERNEL 1603 help 1604 Enable this to turn on extended checks in the priority-ordered 1605 linked-list (plist) walking routines. This checks the entire 1606 list multiple times during each manipulation. 1607 1608 If unsure, say N. 1609 1610config DEBUG_SG 1611 bool "Debug SG table operations" 1612 depends on DEBUG_KERNEL 1613 help 1614 Enable this to turn on checks on scatter-gather tables. This can 1615 help find problems with drivers that do not properly initialize 1616 their sg tables. 1617 1618 If unsure, say N. 1619 1620config DEBUG_NOTIFIERS 1621 bool "Debug notifier call chains" 1622 depends on DEBUG_KERNEL 1623 help 1624 Enable this to turn on sanity checking for notifier call chains. 1625 This is most useful for kernel developers to make sure that 1626 modules properly unregister themselves from notifier chains. 1627 This is a relatively cheap check but if you care about maximum 1628 performance, say N. 1629 1630config BUG_ON_DATA_CORRUPTION 1631 bool "Trigger a BUG when data corruption is detected" 1632 select DEBUG_LIST 1633 help 1634 Select this option if the kernel should BUG when it encounters 1635 data corruption in kernel memory structures when they get checked 1636 for validity. 1637 1638 If unsure, say N. 1639 1640endmenu 1641 1642config DEBUG_CREDENTIALS 1643 bool "Debug credential management" 1644 depends on DEBUG_KERNEL 1645 help 1646 Enable this to turn on some debug checking for credential 1647 management. The additional code keeps track of the number of 1648 pointers from task_structs to any given cred struct, and checks to 1649 see that this number never exceeds the usage count of the cred 1650 struct. 1651 1652 Furthermore, if SELinux is enabled, this also checks that the 1653 security pointer in the cred struct is never seen to be invalid. 1654 1655 If unsure, say N. 1656 1657source "kernel/rcu/Kconfig.debug" 1658 1659config DEBUG_WQ_FORCE_RR_CPU 1660 bool "Force round-robin CPU selection for unbound work items" 1661 depends on DEBUG_KERNEL 1662 default n 1663 help 1664 Workqueue used to implicitly guarantee that work items queued 1665 without explicit CPU specified are put on the local CPU. This 1666 guarantee is no longer true and while local CPU is still 1667 preferred work items may be put on foreign CPUs. Kernel 1668 parameter "workqueue.debug_force_rr_cpu" is added to force 1669 round-robin CPU selection to flush out usages which depend on the 1670 now broken guarantee. This config option enables the debug 1671 feature by default. When enabled, memory and cache locality will 1672 be impacted. 1673 1674config CPU_HOTPLUG_STATE_CONTROL 1675 bool "Enable CPU hotplug state control" 1676 depends on DEBUG_KERNEL 1677 depends on HOTPLUG_CPU 1678 default n 1679 help 1680 Allows to write steps between "offline" and "online" to the CPUs 1681 sysfs target file so states can be stepped granular. This is a debug 1682 option for now as the hotplug machinery cannot be stopped and 1683 restarted at arbitrary points yet. 1684 1685 Say N if your are unsure. 1686 1687config LATENCYTOP 1688 bool "Latency measuring infrastructure" 1689 depends on DEBUG_KERNEL 1690 depends on STACKTRACE_SUPPORT 1691 depends on PROC_FS 1692 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1693 select KALLSYMS 1694 select KALLSYMS_ALL 1695 select STACKTRACE 1696 select SCHEDSTATS 1697 help 1698 Enable this option if you want to use the LatencyTOP tool 1699 to find out which userspace is blocking on what kernel operations. 1700 1701source "kernel/trace/Kconfig" 1702 1703config PROVIDE_OHCI1394_DMA_INIT 1704 bool "Remote debugging over FireWire early on boot" 1705 depends on PCI && X86 1706 help 1707 If you want to debug problems which hang or crash the kernel early 1708 on boot and the crashing machine has a FireWire port, you can use 1709 this feature to remotely access the memory of the crashed machine 1710 over FireWire. This employs remote DMA as part of the OHCI1394 1711 specification which is now the standard for FireWire controllers. 1712 1713 With remote DMA, you can monitor the printk buffer remotely using 1714 firescope and access all memory below 4GB using fireproxy from gdb. 1715 Even controlling a kernel debugger is possible using remote DMA. 1716 1717 Usage: 1718 1719 If ohci1394_dma=early is used as boot parameter, it will initialize 1720 all OHCI1394 controllers which are found in the PCI config space. 1721 1722 As all changes to the FireWire bus such as enabling and disabling 1723 devices cause a bus reset and thereby disable remote DMA for all 1724 devices, be sure to have the cable plugged and FireWire enabled on 1725 the debugging host before booting the debug target for debugging. 1726 1727 This code (~1k) is freed after boot. By then, the firewire stack 1728 in charge of the OHCI-1394 controllers should be used instead. 1729 1730 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1731 1732source "samples/Kconfig" 1733 1734config ARCH_HAS_DEVMEM_IS_ALLOWED 1735 bool 1736 1737config STRICT_DEVMEM 1738 bool "Filter access to /dev/mem" 1739 depends on MMU && DEVMEM 1740 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1741 default y if PPC || X86 || ARM64 1742 help 1743 If this option is disabled, you allow userspace (root) access to all 1744 of memory, including kernel and userspace memory. Accidental 1745 access to this is obviously disastrous, but specific access can 1746 be used by people debugging the kernel. Note that with PAT support 1747 enabled, even in this case there are restrictions on /dev/mem 1748 use due to the cache aliasing requirements. 1749 1750 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1751 file only allows userspace access to PCI space and the BIOS code and 1752 data regions. This is sufficient for dosemu and X and all common 1753 users of /dev/mem. 1754 1755 If in doubt, say Y. 1756 1757config IO_STRICT_DEVMEM 1758 bool "Filter I/O access to /dev/mem" 1759 depends on STRICT_DEVMEM 1760 help 1761 If this option is disabled, you allow userspace (root) access to all 1762 io-memory regardless of whether a driver is actively using that 1763 range. Accidental access to this is obviously disastrous, but 1764 specific access can be used by people debugging kernel drivers. 1765 1766 If this option is switched on, the /dev/mem file only allows 1767 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1768 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1769 if the driver using a given range cannot be disabled. 1770 1771 If in doubt, say Y. 1772 1773menu "$(SRCARCH) Debugging" 1774 1775source "arch/$(SRCARCH)/Kconfig.debug" 1776 1777endmenu 1778 1779menu "Kernel Testing and Coverage" 1780 1781source "lib/kunit/Kconfig" 1782 1783config NOTIFIER_ERROR_INJECTION 1784 tristate "Notifier error injection" 1785 depends on DEBUG_KERNEL 1786 select DEBUG_FS 1787 help 1788 This option provides the ability to inject artificial errors to 1789 specified notifier chain callbacks. It is useful to test the error 1790 handling of notifier call chain failures. 1791 1792 Say N if unsure. 1793 1794config PM_NOTIFIER_ERROR_INJECT 1795 tristate "PM notifier error injection module" 1796 depends on PM && NOTIFIER_ERROR_INJECTION 1797 default m if PM_DEBUG 1798 help 1799 This option provides the ability to inject artificial errors to 1800 PM notifier chain callbacks. It is controlled through debugfs 1801 interface /sys/kernel/debug/notifier-error-inject/pm 1802 1803 If the notifier call chain should be failed with some events 1804 notified, write the error code to "actions/<notifier event>/error". 1805 1806 Example: Inject PM suspend error (-12 = -ENOMEM) 1807 1808 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1809 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1810 # echo mem > /sys/power/state 1811 bash: echo: write error: Cannot allocate memory 1812 1813 To compile this code as a module, choose M here: the module will 1814 be called pm-notifier-error-inject. 1815 1816 If unsure, say N. 1817 1818config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1819 tristate "OF reconfig notifier error injection module" 1820 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1821 help 1822 This option provides the ability to inject artificial errors to 1823 OF reconfig notifier chain callbacks. It is controlled 1824 through debugfs interface under 1825 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1826 1827 If the notifier call chain should be failed with some events 1828 notified, write the error code to "actions/<notifier event>/error". 1829 1830 To compile this code as a module, choose M here: the module will 1831 be called of-reconfig-notifier-error-inject. 1832 1833 If unsure, say N. 1834 1835config NETDEV_NOTIFIER_ERROR_INJECT 1836 tristate "Netdev notifier error injection module" 1837 depends on NET && NOTIFIER_ERROR_INJECTION 1838 help 1839 This option provides the ability to inject artificial errors to 1840 netdevice notifier chain callbacks. It is controlled through debugfs 1841 interface /sys/kernel/debug/notifier-error-inject/netdev 1842 1843 If the notifier call chain should be failed with some events 1844 notified, write the error code to "actions/<notifier event>/error". 1845 1846 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1847 1848 # cd /sys/kernel/debug/notifier-error-inject/netdev 1849 # echo -22 > actions/NETDEV_CHANGEMTU/error 1850 # ip link set eth0 mtu 1024 1851 RTNETLINK answers: Invalid argument 1852 1853 To compile this code as a module, choose M here: the module will 1854 be called netdev-notifier-error-inject. 1855 1856 If unsure, say N. 1857 1858config FUNCTION_ERROR_INJECTION 1859 def_bool y 1860 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1861 1862config FAULT_INJECTION 1863 bool "Fault-injection framework" 1864 depends on DEBUG_KERNEL 1865 help 1866 Provide fault-injection framework. 1867 For more details, see Documentation/fault-injection/. 1868 1869config FAILSLAB 1870 bool "Fault-injection capability for kmalloc" 1871 depends on FAULT_INJECTION 1872 depends on SLAB || SLUB 1873 help 1874 Provide fault-injection capability for kmalloc. 1875 1876config FAIL_PAGE_ALLOC 1877 bool "Fault-injection capability for alloc_pages()" 1878 depends on FAULT_INJECTION 1879 help 1880 Provide fault-injection capability for alloc_pages(). 1881 1882config FAULT_INJECTION_USERCOPY 1883 bool "Fault injection capability for usercopy functions" 1884 depends on FAULT_INJECTION 1885 help 1886 Provides fault-injection capability to inject failures 1887 in usercopy functions (copy_from_user(), get_user(), ...). 1888 1889config FAIL_MAKE_REQUEST 1890 bool "Fault-injection capability for disk IO" 1891 depends on FAULT_INJECTION && BLOCK 1892 help 1893 Provide fault-injection capability for disk IO. 1894 1895config FAIL_IO_TIMEOUT 1896 bool "Fault-injection capability for faking disk interrupts" 1897 depends on FAULT_INJECTION && BLOCK 1898 help 1899 Provide fault-injection capability on end IO handling. This 1900 will make the block layer "forget" an interrupt as configured, 1901 thus exercising the error handling. 1902 1903 Only works with drivers that use the generic timeout handling, 1904 for others it won't do anything. 1905 1906config FAIL_FUTEX 1907 bool "Fault-injection capability for futexes" 1908 select DEBUG_FS 1909 depends on FAULT_INJECTION && FUTEX 1910 help 1911 Provide fault-injection capability for futexes. 1912 1913config FAULT_INJECTION_DEBUG_FS 1914 bool "Debugfs entries for fault-injection capabilities" 1915 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1916 help 1917 Enable configuration of fault-injection capabilities via debugfs. 1918 1919config FAIL_FUNCTION 1920 bool "Fault-injection capability for functions" 1921 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1922 help 1923 Provide function-based fault-injection capability. 1924 This will allow you to override a specific function with a return 1925 with given return value. As a result, function caller will see 1926 an error value and have to handle it. This is useful to test the 1927 error handling in various subsystems. 1928 1929config FAIL_MMC_REQUEST 1930 bool "Fault-injection capability for MMC IO" 1931 depends on FAULT_INJECTION_DEBUG_FS && MMC 1932 help 1933 Provide fault-injection capability for MMC IO. 1934 This will make the mmc core return data errors. This is 1935 useful to test the error handling in the mmc block device 1936 and to test how the mmc host driver handles retries from 1937 the block device. 1938 1939config FAIL_SUNRPC 1940 bool "Fault-injection capability for SunRPC" 1941 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1942 help 1943 Provide fault-injection capability for SunRPC and 1944 its consumers. 1945 1946config FAULT_INJECTION_STACKTRACE_FILTER 1947 bool "stacktrace filter for fault-injection capabilities" 1948 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1949 depends on !X86_64 1950 select STACKTRACE 1951 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1952 help 1953 Provide stacktrace filter for fault-injection capabilities 1954 1955config ARCH_HAS_KCOV 1956 bool 1957 help 1958 An architecture should select this when it can successfully 1959 build and run with CONFIG_KCOV. This typically requires 1960 disabling instrumentation for some early boot code. 1961 1962config CC_HAS_SANCOV_TRACE_PC 1963 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1964 1965 1966config KCOV 1967 bool "Code coverage for fuzzing" 1968 depends on ARCH_HAS_KCOV 1969 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1970 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 1971 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 1972 select DEBUG_FS 1973 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1974 select OBJTOOL if HAVE_NOINSTR_HACK 1975 help 1976 KCOV exposes kernel code coverage information in a form suitable 1977 for coverage-guided fuzzing (randomized testing). 1978 1979 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1980 different machines and across reboots. If you need stable PC values, 1981 disable RANDOMIZE_BASE. 1982 1983 For more details, see Documentation/dev-tools/kcov.rst. 1984 1985config KCOV_ENABLE_COMPARISONS 1986 bool "Enable comparison operands collection by KCOV" 1987 depends on KCOV 1988 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 1989 help 1990 KCOV also exposes operands of every comparison in the instrumented 1991 code along with operand sizes and PCs of the comparison instructions. 1992 These operands can be used by fuzzing engines to improve the quality 1993 of fuzzing coverage. 1994 1995config KCOV_INSTRUMENT_ALL 1996 bool "Instrument all code by default" 1997 depends on KCOV 1998 default y 1999 help 2000 If you are doing generic system call fuzzing (like e.g. syzkaller), 2001 then you will want to instrument the whole kernel and you should 2002 say y here. If you are doing more targeted fuzzing (like e.g. 2003 filesystem fuzzing with AFL) then you will want to enable coverage 2004 for more specific subsets of files, and should say n here. 2005 2006config KCOV_IRQ_AREA_SIZE 2007 hex "Size of interrupt coverage collection area in words" 2008 depends on KCOV 2009 default 0x40000 2010 help 2011 KCOV uses preallocated per-cpu areas to collect coverage from 2012 soft interrupts. This specifies the size of those areas in the 2013 number of unsigned long words. 2014 2015menuconfig RUNTIME_TESTING_MENU 2016 bool "Runtime Testing" 2017 def_bool y 2018 2019if RUNTIME_TESTING_MENU 2020 2021config LKDTM 2022 tristate "Linux Kernel Dump Test Tool Module" 2023 depends on DEBUG_FS 2024 help 2025 This module enables testing of the different dumping mechanisms by 2026 inducing system failures at predefined crash points. 2027 If you don't need it: say N 2028 Choose M here to compile this code as a module. The module will be 2029 called lkdtm. 2030 2031 Documentation on how to use the module can be found in 2032 Documentation/fault-injection/provoke-crashes.rst 2033 2034config CPUMASK_KUNIT_TEST 2035 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2036 depends on KUNIT 2037 default KUNIT_ALL_TESTS 2038 help 2039 Enable to turn on cpumask tests, running at boot or module load time. 2040 2041 For more information on KUnit and unit tests in general, please refer 2042 to the KUnit documentation in Documentation/dev-tools/kunit/. 2043 2044 If unsure, say N. 2045 2046config TEST_LIST_SORT 2047 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2048 depends on KUNIT 2049 default KUNIT_ALL_TESTS 2050 help 2051 Enable this to turn on 'list_sort()' function test. This test is 2052 executed only once during system boot (so affects only boot time), 2053 or at module load time. 2054 2055 If unsure, say N. 2056 2057config TEST_MIN_HEAP 2058 tristate "Min heap test" 2059 depends on DEBUG_KERNEL || m 2060 help 2061 Enable this to turn on min heap function tests. This test is 2062 executed only once during system boot (so affects only boot time), 2063 or at module load time. 2064 2065 If unsure, say N. 2066 2067config TEST_SORT 2068 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2069 depends on KUNIT 2070 default KUNIT_ALL_TESTS 2071 help 2072 This option enables the self-test function of 'sort()' at boot, 2073 or at module load time. 2074 2075 If unsure, say N. 2076 2077config TEST_DIV64 2078 tristate "64bit/32bit division and modulo test" 2079 depends on DEBUG_KERNEL || m 2080 help 2081 Enable this to turn on 'do_div()' function test. This test is 2082 executed only once during system boot (so affects only boot time), 2083 or at module load time. 2084 2085 If unsure, say N. 2086 2087config KPROBES_SANITY_TEST 2088 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2089 depends on DEBUG_KERNEL 2090 depends on KPROBES 2091 depends on KUNIT 2092 default KUNIT_ALL_TESTS 2093 help 2094 This option provides for testing basic kprobes functionality on 2095 boot. Samples of kprobe and kretprobe are inserted and 2096 verified for functionality. 2097 2098 Say N if you are unsure. 2099 2100config FPROBE_SANITY_TEST 2101 bool "Self test for fprobe" 2102 depends on DEBUG_KERNEL 2103 depends on FPROBE 2104 depends on KUNIT=y 2105 help 2106 This option will enable testing the fprobe when the system boot. 2107 A series of tests are made to verify that the fprobe is functioning 2108 properly. 2109 2110 Say N if you are unsure. 2111 2112config BACKTRACE_SELF_TEST 2113 tristate "Self test for the backtrace code" 2114 depends on DEBUG_KERNEL 2115 help 2116 This option provides a kernel module that can be used to test 2117 the kernel stack backtrace code. This option is not useful 2118 for distributions or general kernels, but only for kernel 2119 developers working on architecture code. 2120 2121 Note that if you want to also test saved backtraces, you will 2122 have to enable STACKTRACE as well. 2123 2124 Say N if you are unsure. 2125 2126config TEST_REF_TRACKER 2127 tristate "Self test for reference tracker" 2128 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2129 select REF_TRACKER 2130 help 2131 This option provides a kernel module performing tests 2132 using reference tracker infrastructure. 2133 2134 Say N if you are unsure. 2135 2136config RBTREE_TEST 2137 tristate "Red-Black tree test" 2138 depends on DEBUG_KERNEL 2139 help 2140 A benchmark measuring the performance of the rbtree library. 2141 Also includes rbtree invariant checks. 2142 2143config REED_SOLOMON_TEST 2144 tristate "Reed-Solomon library test" 2145 depends on DEBUG_KERNEL || m 2146 select REED_SOLOMON 2147 select REED_SOLOMON_ENC16 2148 select REED_SOLOMON_DEC16 2149 help 2150 This option enables the self-test function of rslib at boot, 2151 or at module load time. 2152 2153 If unsure, say N. 2154 2155config INTERVAL_TREE_TEST 2156 tristate "Interval tree test" 2157 depends on DEBUG_KERNEL 2158 select INTERVAL_TREE 2159 help 2160 A benchmark measuring the performance of the interval tree library 2161 2162config PERCPU_TEST 2163 tristate "Per cpu operations test" 2164 depends on m && DEBUG_KERNEL 2165 help 2166 Enable this option to build test module which validates per-cpu 2167 operations. 2168 2169 If unsure, say N. 2170 2171config ATOMIC64_SELFTEST 2172 tristate "Perform an atomic64_t self-test" 2173 help 2174 Enable this option to test the atomic64_t functions at boot or 2175 at module load time. 2176 2177 If unsure, say N. 2178 2179config ASYNC_RAID6_TEST 2180 tristate "Self test for hardware accelerated raid6 recovery" 2181 depends on ASYNC_RAID6_RECOV 2182 select ASYNC_MEMCPY 2183 help 2184 This is a one-shot self test that permutes through the 2185 recovery of all the possible two disk failure scenarios for a 2186 N-disk array. Recovery is performed with the asynchronous 2187 raid6 recovery routines, and will optionally use an offload 2188 engine if one is available. 2189 2190 If unsure, say N. 2191 2192config TEST_HEXDUMP 2193 tristate "Test functions located in the hexdump module at runtime" 2194 2195config STRING_SELFTEST 2196 tristate "Test string functions at runtime" 2197 2198config TEST_STRING_HELPERS 2199 tristate "Test functions located in the string_helpers module at runtime" 2200 2201config TEST_STRSCPY 2202 tristate "Test strscpy*() family of functions at runtime" 2203 2204config TEST_KSTRTOX 2205 tristate "Test kstrto*() family of functions at runtime" 2206 2207config TEST_PRINTF 2208 tristate "Test printf() family of functions at runtime" 2209 2210config TEST_SCANF 2211 tristate "Test scanf() family of functions at runtime" 2212 2213config TEST_BITMAP 2214 tristate "Test bitmap_*() family of functions at runtime" 2215 help 2216 Enable this option to test the bitmap functions at boot. 2217 2218 If unsure, say N. 2219 2220config TEST_UUID 2221 tristate "Test functions located in the uuid module at runtime" 2222 2223config TEST_XARRAY 2224 tristate "Test the XArray code at runtime" 2225 2226config TEST_RHASHTABLE 2227 tristate "Perform selftest on resizable hash table" 2228 help 2229 Enable this option to test the rhashtable functions at boot. 2230 2231 If unsure, say N. 2232 2233config TEST_SIPHASH 2234 tristate "Perform selftest on siphash functions" 2235 help 2236 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2237 functions on boot (or module load). 2238 2239 This is intended to help people writing architecture-specific 2240 optimized versions. If unsure, say N. 2241 2242config TEST_IDA 2243 tristate "Perform selftest on IDA functions" 2244 2245config TEST_PARMAN 2246 tristate "Perform selftest on priority array manager" 2247 depends on PARMAN 2248 help 2249 Enable this option to test priority array manager on boot 2250 (or module load). 2251 2252 If unsure, say N. 2253 2254config TEST_IRQ_TIMINGS 2255 bool "IRQ timings selftest" 2256 depends on IRQ_TIMINGS 2257 help 2258 Enable this option to test the irq timings code on boot. 2259 2260 If unsure, say N. 2261 2262config TEST_LKM 2263 tristate "Test module loading with 'hello world' module" 2264 depends on m 2265 help 2266 This builds the "test_module" module that emits "Hello, world" 2267 on printk when loaded. It is designed to be used for basic 2268 evaluation of the module loading subsystem (for example when 2269 validating module verification). It lacks any extra dependencies, 2270 and will not normally be loaded by the system unless explicitly 2271 requested by name. 2272 2273 If unsure, say N. 2274 2275config TEST_BITOPS 2276 tristate "Test module for compilation of bitops operations" 2277 depends on m 2278 help 2279 This builds the "test_bitops" module that is much like the 2280 TEST_LKM module except that it does a basic exercise of the 2281 set/clear_bit macros and get_count_order/long to make sure there are 2282 no compiler warnings from C=1 sparse checker or -Wextra 2283 compilations. It has no dependencies and doesn't run or load unless 2284 explicitly requested by name. for example: modprobe test_bitops. 2285 2286 If unsure, say N. 2287 2288config TEST_VMALLOC 2289 tristate "Test module for stress/performance analysis of vmalloc allocator" 2290 default n 2291 depends on MMU 2292 depends on m 2293 help 2294 This builds the "test_vmalloc" module that should be used for 2295 stress and performance analysis. So, any new change for vmalloc 2296 subsystem can be evaluated from performance and stability point 2297 of view. 2298 2299 If unsure, say N. 2300 2301config TEST_USER_COPY 2302 tristate "Test user/kernel boundary protections" 2303 depends on m 2304 help 2305 This builds the "test_user_copy" module that runs sanity checks 2306 on the copy_to/from_user infrastructure, making sure basic 2307 user/kernel boundary testing is working. If it fails to load, 2308 a regression has been detected in the user/kernel memory boundary 2309 protections. 2310 2311 If unsure, say N. 2312 2313config TEST_BPF 2314 tristate "Test BPF filter functionality" 2315 depends on m && NET 2316 help 2317 This builds the "test_bpf" module that runs various test vectors 2318 against the BPF interpreter or BPF JIT compiler depending on the 2319 current setting. This is in particular useful for BPF JIT compiler 2320 development, but also to run regression tests against changes in 2321 the interpreter code. It also enables test stubs for eBPF maps and 2322 verifier used by user space verifier testsuite. 2323 2324 If unsure, say N. 2325 2326config TEST_BLACKHOLE_DEV 2327 tristate "Test blackhole netdev functionality" 2328 depends on m && NET 2329 help 2330 This builds the "test_blackhole_dev" module that validates the 2331 data path through this blackhole netdev. 2332 2333 If unsure, say N. 2334 2335config FIND_BIT_BENCHMARK 2336 tristate "Test find_bit functions" 2337 help 2338 This builds the "test_find_bit" module that measure find_*_bit() 2339 functions performance. 2340 2341 If unsure, say N. 2342 2343config TEST_FIRMWARE 2344 tristate "Test firmware loading via userspace interface" 2345 depends on FW_LOADER 2346 help 2347 This builds the "test_firmware" module that creates a userspace 2348 interface for testing firmware loading. This can be used to 2349 control the triggering of firmware loading without needing an 2350 actual firmware-using device. The contents can be rechecked by 2351 userspace. 2352 2353 If unsure, say N. 2354 2355config TEST_SYSCTL 2356 tristate "sysctl test driver" 2357 depends on PROC_SYSCTL 2358 help 2359 This builds the "test_sysctl" module. This driver enables to test the 2360 proc sysctl interfaces available to drivers safely without affecting 2361 production knobs which might alter system functionality. 2362 2363 If unsure, say N. 2364 2365config BITFIELD_KUNIT 2366 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2367 depends on KUNIT 2368 default KUNIT_ALL_TESTS 2369 help 2370 Enable this option to test the bitfield functions at boot. 2371 2372 KUnit tests run during boot and output the results to the debug log 2373 in TAP format (http://testanything.org/). Only useful for kernel devs 2374 running the KUnit test harness, and not intended for inclusion into a 2375 production build. 2376 2377 For more information on KUnit and unit tests in general please refer 2378 to the KUnit documentation in Documentation/dev-tools/kunit/. 2379 2380 If unsure, say N. 2381 2382config HASH_KUNIT_TEST 2383 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2384 depends on KUNIT 2385 default KUNIT_ALL_TESTS 2386 help 2387 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2388 integer (<linux/hash.h>) hash functions on boot. 2389 2390 KUnit tests run during boot and output the results to the debug log 2391 in TAP format (https://testanything.org/). Only useful for kernel devs 2392 running the KUnit test harness, and not intended for inclusion into a 2393 production build. 2394 2395 For more information on KUnit and unit tests in general please refer 2396 to the KUnit documentation in Documentation/dev-tools/kunit/. 2397 2398 This is intended to help people writing architecture-specific 2399 optimized versions. If unsure, say N. 2400 2401config RESOURCE_KUNIT_TEST 2402 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2403 depends on KUNIT 2404 default KUNIT_ALL_TESTS 2405 help 2406 This builds the resource API unit test. 2407 Tests the logic of API provided by resource.c and ioport.h. 2408 For more information on KUnit and unit tests in general please refer 2409 to the KUnit documentation in Documentation/dev-tools/kunit/. 2410 2411 If unsure, say N. 2412 2413config SYSCTL_KUNIT_TEST 2414 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2415 depends on KUNIT 2416 default KUNIT_ALL_TESTS 2417 help 2418 This builds the proc sysctl unit test, which runs on boot. 2419 Tests the API contract and implementation correctness of sysctl. 2420 For more information on KUnit and unit tests in general please refer 2421 to the KUnit documentation in Documentation/dev-tools/kunit/. 2422 2423 If unsure, say N. 2424 2425config LIST_KUNIT_TEST 2426 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2427 depends on KUNIT 2428 default KUNIT_ALL_TESTS 2429 help 2430 This builds the linked list KUnit test suite. 2431 It tests that the API and basic functionality of the list_head type 2432 and associated macros. 2433 2434 KUnit tests run during boot and output the results to the debug log 2435 in TAP format (https://testanything.org/). Only useful for kernel devs 2436 running the KUnit test harness, and not intended for inclusion into a 2437 production build. 2438 2439 For more information on KUnit and unit tests in general please refer 2440 to the KUnit documentation in Documentation/dev-tools/kunit/. 2441 2442 If unsure, say N. 2443 2444config LINEAR_RANGES_TEST 2445 tristate "KUnit test for linear_ranges" 2446 depends on KUNIT 2447 select LINEAR_RANGES 2448 help 2449 This builds the linear_ranges unit test, which runs on boot. 2450 Tests the linear_ranges logic correctness. 2451 For more information on KUnit and unit tests in general please refer 2452 to the KUnit documentation in Documentation/dev-tools/kunit/. 2453 2454 If unsure, say N. 2455 2456config CMDLINE_KUNIT_TEST 2457 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2458 depends on KUNIT 2459 default KUNIT_ALL_TESTS 2460 help 2461 This builds the cmdline API unit test. 2462 Tests the logic of API provided by cmdline.c. 2463 For more information on KUnit and unit tests in general please refer 2464 to the KUnit documentation in Documentation/dev-tools/kunit/. 2465 2466 If unsure, say N. 2467 2468config BITS_TEST 2469 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2470 depends on KUNIT 2471 default KUNIT_ALL_TESTS 2472 help 2473 This builds the bits unit test. 2474 Tests the logic of macros defined in bits.h. 2475 For more information on KUnit and unit tests in general please refer 2476 to the KUnit documentation in Documentation/dev-tools/kunit/. 2477 2478 If unsure, say N. 2479 2480config SLUB_KUNIT_TEST 2481 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2482 depends on SLUB_DEBUG && KUNIT 2483 default KUNIT_ALL_TESTS 2484 help 2485 This builds SLUB allocator unit test. 2486 Tests SLUB cache debugging functionality. 2487 For more information on KUnit and unit tests in general please refer 2488 to the KUnit documentation in Documentation/dev-tools/kunit/. 2489 2490 If unsure, say N. 2491 2492config RATIONAL_KUNIT_TEST 2493 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2494 depends on KUNIT && RATIONAL 2495 default KUNIT_ALL_TESTS 2496 help 2497 This builds the rational math unit test. 2498 For more information on KUnit and unit tests in general please refer 2499 to the KUnit documentation in Documentation/dev-tools/kunit/. 2500 2501 If unsure, say N. 2502 2503config MEMCPY_KUNIT_TEST 2504 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2505 depends on KUNIT 2506 default KUNIT_ALL_TESTS 2507 help 2508 Builds unit tests for memcpy(), memmove(), and memset() functions. 2509 For more information on KUnit and unit tests in general please refer 2510 to the KUnit documentation in Documentation/dev-tools/kunit/. 2511 2512 If unsure, say N. 2513 2514config OVERFLOW_KUNIT_TEST 2515 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2516 depends on KUNIT 2517 default KUNIT_ALL_TESTS 2518 help 2519 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2520 related functions. 2521 2522 For more information on KUnit and unit tests in general please refer 2523 to the KUnit documentation in Documentation/dev-tools/kunit/. 2524 2525 If unsure, say N. 2526 2527config STACKINIT_KUNIT_TEST 2528 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2529 depends on KUNIT 2530 default KUNIT_ALL_TESTS 2531 help 2532 Test if the kernel is zero-initializing stack variables and 2533 padding. Coverage is controlled by compiler flags, 2534 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2535 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2536 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2537 2538config TEST_UDELAY 2539 tristate "udelay test driver" 2540 help 2541 This builds the "udelay_test" module that helps to make sure 2542 that udelay() is working properly. 2543 2544 If unsure, say N. 2545 2546config TEST_STATIC_KEYS 2547 tristate "Test static keys" 2548 depends on m 2549 help 2550 Test the static key interfaces. 2551 2552 If unsure, say N. 2553 2554config TEST_KMOD 2555 tristate "kmod stress tester" 2556 depends on m 2557 depends on NETDEVICES && NET_CORE && INET # for TUN 2558 depends on BLOCK 2559 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2560 select TEST_LKM 2561 select XFS_FS 2562 select TUN 2563 select BTRFS_FS 2564 help 2565 Test the kernel's module loading mechanism: kmod. kmod implements 2566 support to load modules using the Linux kernel's usermode helper. 2567 This test provides a series of tests against kmod. 2568 2569 Although technically you can either build test_kmod as a module or 2570 into the kernel we disallow building it into the kernel since 2571 it stress tests request_module() and this will very likely cause 2572 some issues by taking over precious threads available from other 2573 module load requests, ultimately this could be fatal. 2574 2575 To run tests run: 2576 2577 tools/testing/selftests/kmod/kmod.sh --help 2578 2579 If unsure, say N. 2580 2581config TEST_DEBUG_VIRTUAL 2582 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2583 depends on DEBUG_VIRTUAL 2584 help 2585 Test the kernel's ability to detect incorrect calls to 2586 virt_to_phys() done against the non-linear part of the 2587 kernel's virtual address map. 2588 2589 If unsure, say N. 2590 2591config TEST_MEMCAT_P 2592 tristate "Test memcat_p() helper function" 2593 help 2594 Test the memcat_p() helper for correctly merging two 2595 pointer arrays together. 2596 2597 If unsure, say N. 2598 2599config TEST_LIVEPATCH 2600 tristate "Test livepatching" 2601 default n 2602 depends on DYNAMIC_DEBUG 2603 depends on LIVEPATCH 2604 depends on m 2605 help 2606 Test kernel livepatching features for correctness. The tests will 2607 load test modules that will be livepatched in various scenarios. 2608 2609 To run all the livepatching tests: 2610 2611 make -C tools/testing/selftests TARGETS=livepatch run_tests 2612 2613 Alternatively, individual tests may be invoked: 2614 2615 tools/testing/selftests/livepatch/test-callbacks.sh 2616 tools/testing/selftests/livepatch/test-livepatch.sh 2617 tools/testing/selftests/livepatch/test-shadow-vars.sh 2618 2619 If unsure, say N. 2620 2621config TEST_OBJAGG 2622 tristate "Perform selftest on object aggreration manager" 2623 default n 2624 depends on OBJAGG 2625 help 2626 Enable this option to test object aggregation manager on boot 2627 (or module load). 2628 2629config TEST_MEMINIT 2630 tristate "Test heap/page initialization" 2631 help 2632 Test if the kernel is zero-initializing heap and page allocations. 2633 This can be useful to test init_on_alloc and init_on_free features. 2634 2635 If unsure, say N. 2636 2637config TEST_HMM 2638 tristate "Test HMM (Heterogeneous Memory Management)" 2639 depends on TRANSPARENT_HUGEPAGE 2640 depends on DEVICE_PRIVATE 2641 select HMM_MIRROR 2642 select MMU_NOTIFIER 2643 help 2644 This is a pseudo device driver solely for testing HMM. 2645 Say M here if you want to build the HMM test module. 2646 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2647 2648 If unsure, say N. 2649 2650config TEST_FREE_PAGES 2651 tristate "Test freeing pages" 2652 help 2653 Test that a memory leak does not occur due to a race between 2654 freeing a block of pages and a speculative page reference. 2655 Loading this module is safe if your kernel has the bug fixed. 2656 If the bug is not fixed, it will leak gigabytes of memory and 2657 probably OOM your system. 2658 2659config TEST_FPU 2660 tristate "Test floating point operations in kernel space" 2661 depends on X86 && !KCOV_INSTRUMENT_ALL 2662 help 2663 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2664 which will trigger a sequence of floating point operations. This is used 2665 for self-testing floating point control register setting in 2666 kernel_fpu_begin(). 2667 2668 If unsure, say N. 2669 2670config TEST_CLOCKSOURCE_WATCHDOG 2671 tristate "Test clocksource watchdog in kernel space" 2672 depends on CLOCKSOURCE_WATCHDOG 2673 help 2674 Enable this option to create a kernel module that will trigger 2675 a test of the clocksource watchdog. This module may be loaded 2676 via modprobe or insmod in which case it will run upon being 2677 loaded, or it may be built in, in which case it will run 2678 shortly after boot. 2679 2680 If unsure, say N. 2681 2682endif # RUNTIME_TESTING_MENU 2683 2684config ARCH_USE_MEMTEST 2685 bool 2686 help 2687 An architecture should select this when it uses early_memtest() 2688 during boot process. 2689 2690config MEMTEST 2691 bool "Memtest" 2692 depends on ARCH_USE_MEMTEST 2693 help 2694 This option adds a kernel parameter 'memtest', which allows memtest 2695 to be set and executed. 2696 memtest=0, mean disabled; -- default 2697 memtest=1, mean do 1 test pattern; 2698 ... 2699 memtest=17, mean do 17 test patterns. 2700 If you are unsure how to answer this question, answer N. 2701 2702 2703 2704config HYPERV_TESTING 2705 bool "Microsoft Hyper-V driver testing" 2706 default n 2707 depends on HYPERV && DEBUG_FS 2708 help 2709 Select this option to enable Hyper-V vmbus testing. 2710 2711endmenu # "Kernel Testing and Coverage" 2712 2713source "Documentation/Kconfig" 2714 2715endmenu # Kernel hacking 2716