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 help 268 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. 269 270 If you have consumers of DWARF debug info that are not ready for 271 newer revisions of DWARF, you may wish to choose this or have your 272 config select this. 273 274config DEBUG_INFO_DWARF5 275 bool "Generate DWARF Version 5 debuginfo" 276 select DEBUG_INFO 277 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) 278 help 279 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 280 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 281 draft features until 7.0), and gdb 8.0+. 282 283 Changes to the structure of debug info in Version 5 allow for around 284 15-18% savings in resulting image and debug info section sizes as 285 compared to DWARF Version 4. DWARF Version 5 standardizes previous 286 extensions such as accelerators for symbol indexing and the format 287 for fission (.dwo/.dwp) files. Users may not want to select this 288 config if they rely on tooling that has not yet been updated to 289 support DWARF Version 5. 290 291endchoice # "Debug information" 292 293if DEBUG_INFO 294 295config DEBUG_INFO_REDUCED 296 bool "Reduce debugging information" 297 help 298 If you say Y here gcc is instructed to generate less debugging 299 information for structure types. This means that tools that 300 need full debugging information (like kgdb or systemtap) won't 301 be happy. But if you merely need debugging information to 302 resolve line numbers there is no loss. Advantage is that 303 build directory object sizes shrink dramatically over a full 304 DEBUG_INFO build and compile times are reduced too. 305 Only works with newer gcc versions. 306 307config DEBUG_INFO_COMPRESSED 308 bool "Compressed debugging information" 309 depends on $(cc-option,-gz=zlib) 310 depends on $(ld-option,--compress-debug-sections=zlib) 311 help 312 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 313 5.0+, binutils 2.26+, and zlib. 314 315 Users of dpkg-deb via scripts/package/builddeb may find an increase in 316 size of their debug .deb packages with this config set, due to the 317 debug info being compressed with zlib, then the object files being 318 recompressed with a different compression scheme. But this is still 319 preferable to setting $KDEB_COMPRESS to "none" which would be even 320 larger. 321 322config DEBUG_INFO_SPLIT 323 bool "Produce split debuginfo in .dwo files" 324 depends on $(cc-option,-gsplit-dwarf) 325 help 326 Generate debug info into separate .dwo files. This significantly 327 reduces the build directory size for builds with DEBUG_INFO, 328 because it stores the information only once on disk in .dwo 329 files instead of multiple times in object files and executables. 330 In addition the debug information is also compressed. 331 332 Requires recent gcc (4.7+) and recent gdb/binutils. 333 Any tool that packages or reads debug information would need 334 to know about the .dwo files and include them. 335 Incompatible with older versions of ccache. 336 337config DEBUG_INFO_BTF 338 bool "Generate BTF typeinfo" 339 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 340 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 341 depends on BPF_SYSCALL 342 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 343 help 344 Generate deduplicated BTF type information from DWARF debug info. 345 Turning this on expects presence of pahole tool, which will convert 346 DWARF type info into equivalent deduplicated BTF type info. 347 348config PAHOLE_HAS_SPLIT_BTF 349 def_bool PAHOLE_VERSION >= 119 350 351config PAHOLE_HAS_BTF_TAG 352 def_bool PAHOLE_VERSION >= 123 353 depends on CC_IS_CLANG 354 help 355 Decide whether pahole emits btf_tag attributes (btf_type_tag and 356 btf_decl_tag) or not. Currently only clang compiler implements 357 these attributes, so make the config depend on CC_IS_CLANG. 358 359config DEBUG_INFO_BTF_MODULES 360 def_bool y 361 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 362 help 363 Generate compact split BTF type information for kernel modules. 364 365config MODULE_ALLOW_BTF_MISMATCH 366 bool "Allow loading modules with non-matching BTF type info" 367 depends on DEBUG_INFO_BTF_MODULES 368 help 369 For modules whose split BTF does not match vmlinux, load without 370 BTF rather than refusing to load. The default behavior with 371 module BTF enabled is to reject modules with such mismatches; 372 this option will still load module BTF where possible but ignore 373 it when a mismatch is found. 374 375config GDB_SCRIPTS 376 bool "Provide GDB scripts for kernel debugging" 377 help 378 This creates the required links to GDB helper scripts in the 379 build directory. If you load vmlinux into gdb, the helper 380 scripts will be automatically imported by gdb as well, and 381 additional functions are available to analyze a Linux kernel 382 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 383 for further details. 384 385endif # DEBUG_INFO 386 387config FRAME_WARN 388 int "Warn for stack frames larger than" 389 range 0 8192 390 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 391 default 2048 if PARISC 392 default 1536 if (!64BIT && XTENSA) 393 default 1024 if !64BIT 394 default 2048 if 64BIT 395 help 396 Tell gcc to warn at build time for stack frames larger than this. 397 Setting this too low will cause a lot of warnings. 398 Setting it to 0 disables the warning. 399 400config STRIP_ASM_SYMS 401 bool "Strip assembler-generated symbols during link" 402 default n 403 help 404 Strip internal assembler-generated symbols during a link (symbols 405 that look like '.Lxxx') so they don't pollute the output of 406 get_wchan() and suchlike. 407 408config READABLE_ASM 409 bool "Generate readable assembler code" 410 depends on DEBUG_KERNEL 411 depends on CC_IS_GCC 412 help 413 Disable some compiler optimizations that tend to generate human unreadable 414 assembler output. This may make the kernel slightly slower, but it helps 415 to keep kernel developers who have to stare a lot at assembler listings 416 sane. 417 418config HEADERS_INSTALL 419 bool "Install uapi headers to usr/include" 420 depends on !UML 421 help 422 This option will install uapi headers (headers exported to user-space) 423 into the usr/include directory for use during the kernel build. 424 This is unneeded for building the kernel itself, but needed for some 425 user-space program samples. It is also needed by some features such 426 as uapi header sanity checks. 427 428config DEBUG_SECTION_MISMATCH 429 bool "Enable full Section mismatch analysis" 430 depends on CC_IS_GCC 431 help 432 The section mismatch analysis checks if there are illegal 433 references from one section to another section. 434 During linktime or runtime, some sections are dropped; 435 any use of code/data previously in these sections would 436 most likely result in an oops. 437 In the code, functions and variables are annotated with 438 __init,, etc. (see the full list in include/linux/init.h), 439 which results in the code/data being placed in specific sections. 440 The section mismatch analysis is always performed after a full 441 kernel build, and enabling this option causes the following 442 additional step to occur: 443 - Add the option -fno-inline-functions-called-once to gcc commands. 444 When inlining a function annotated with __init in a non-init 445 function, we would lose the section information and thus 446 the analysis would not catch the illegal reference. 447 This option tells gcc to inline less (but it does result in 448 a larger kernel). 449 450config SECTION_MISMATCH_WARN_ONLY 451 bool "Make section mismatch errors non-fatal" 452 default y 453 help 454 If you say N here, the build process will fail if there are any 455 section mismatch, instead of just throwing warnings. 456 457 If unsure, say Y. 458 459config DEBUG_FORCE_FUNCTION_ALIGN_64B 460 bool "Force all function address 64B aligned" 461 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 462 help 463 There are cases that a commit from one domain changes the function 464 address alignment of other domains, and cause magic performance 465 bump (regression or improvement). Enable this option will help to 466 verify if the bump is caused by function alignment changes, while 467 it will slightly increase the kernel size and affect icache usage. 468 469 It is mainly for debug and performance tuning use. 470 471# 472# Select this config option from the architecture Kconfig, if it 473# is preferred to always offer frame pointers as a config 474# option on the architecture (regardless of KERNEL_DEBUG): 475# 476config ARCH_WANT_FRAME_POINTERS 477 bool 478 479config FRAME_POINTER 480 bool "Compile the kernel with frame pointers" 481 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 482 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 483 help 484 If you say Y here the resulting kernel image will be slightly 485 larger and slower, but it gives very useful debugging information 486 in case of kernel bugs. (precise oopses/stacktraces/warnings) 487 488config OBJTOOL 489 bool 490 491config STACK_VALIDATION 492 bool "Compile-time stack metadata validation" 493 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 494 select OBJTOOL 495 default n 496 help 497 Validate frame pointer rules at compile-time. This helps ensure that 498 runtime stack traces are more reliable. 499 500 For more information, see 501 tools/objtool/Documentation/stack-validation.txt. 502 503config NOINSTR_VALIDATION 504 bool 505 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 506 select OBJTOOL 507 default y 508 509config VMLINUX_MAP 510 bool "Generate vmlinux.map file when linking" 511 depends on EXPERT 512 help 513 Selecting this option will pass "-Map=vmlinux.map" to ld 514 when linking vmlinux. That file can be useful for verifying 515 and debugging magic section games, and for seeing which 516 pieces of code get eliminated with 517 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 518 519config DEBUG_FORCE_WEAK_PER_CPU 520 bool "Force weak per-cpu definitions" 521 depends on DEBUG_KERNEL 522 help 523 s390 and alpha require percpu variables in modules to be 524 defined weak to work around addressing range issue which 525 puts the following two restrictions on percpu variable 526 definitions. 527 528 1. percpu symbols must be unique whether static or not 529 2. percpu variables can't be defined inside a function 530 531 To ensure that generic code follows the above rules, this 532 option forces all percpu variables to be defined as weak. 533 534endmenu # "Compiler options" 535 536menu "Generic Kernel Debugging Instruments" 537 538config MAGIC_SYSRQ 539 bool "Magic SysRq key" 540 depends on !UML 541 help 542 If you say Y here, you will have some control over the system even 543 if the system crashes for example during kernel debugging (e.g., you 544 will be able to flush the buffer cache to disk, reboot the system 545 immediately or dump some status information). This is accomplished 546 by pressing various keys while holding SysRq (Alt+PrintScreen). It 547 also works on a serial console (on PC hardware at least), if you 548 send a BREAK and then within 5 seconds a command keypress. The 549 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 550 Don't say Y unless you really know what this hack does. 551 552config MAGIC_SYSRQ_DEFAULT_ENABLE 553 hex "Enable magic SysRq key functions by default" 554 depends on MAGIC_SYSRQ 555 default 0x1 556 help 557 Specifies which SysRq key functions are enabled by default. 558 This may be set to 1 or 0 to enable or disable them all, or 559 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 560 561config MAGIC_SYSRQ_SERIAL 562 bool "Enable magic SysRq key over serial" 563 depends on MAGIC_SYSRQ 564 default y 565 help 566 Many embedded boards have a disconnected TTL level serial which can 567 generate some garbage that can lead to spurious false sysrq detects. 568 This option allows you to decide whether you want to enable the 569 magic SysRq key. 570 571config MAGIC_SYSRQ_SERIAL_SEQUENCE 572 string "Char sequence that enables magic SysRq over serial" 573 depends on MAGIC_SYSRQ_SERIAL 574 default "" 575 help 576 Specifies a sequence of characters that can follow BREAK to enable 577 SysRq on a serial console. 578 579 If unsure, leave an empty string and the option will not be enabled. 580 581config DEBUG_FS 582 bool "Debug Filesystem" 583 help 584 debugfs is a virtual file system that kernel developers use to put 585 debugging files into. Enable this option to be able to read and 586 write to these files. 587 588 For detailed documentation on the debugfs API, see 589 Documentation/filesystems/. 590 591 If unsure, say N. 592 593choice 594 prompt "Debugfs default access" 595 depends on DEBUG_FS 596 default DEBUG_FS_ALLOW_ALL 597 help 598 This selects the default access restrictions for debugfs. 599 It can be overridden with kernel command line option 600 debugfs=[on,no-mount,off]. The restrictions apply for API access 601 and filesystem registration. 602 603config DEBUG_FS_ALLOW_ALL 604 bool "Access normal" 605 help 606 No restrictions apply. Both API and filesystem registration 607 is on. This is the normal default operation. 608 609config DEBUG_FS_DISALLOW_MOUNT 610 bool "Do not register debugfs as filesystem" 611 help 612 The API is open but filesystem is not loaded. Clients can still do 613 their work and read with debug tools that do not need 614 debugfs filesystem. 615 616config DEBUG_FS_ALLOW_NONE 617 bool "No access" 618 help 619 Access is off. Clients get -PERM when trying to create nodes in 620 debugfs tree and debugfs is not registered as a filesystem. 621 Client can then back-off or continue without debugfs access. 622 623endchoice 624 625source "lib/Kconfig.kgdb" 626source "lib/Kconfig.ubsan" 627source "lib/Kconfig.kcsan" 628 629endmenu 630 631menu "Networking Debugging" 632 633source "net/Kconfig.debug" 634 635endmenu # "Networking Debugging" 636 637menu "Memory Debugging" 638 639source "mm/Kconfig.debug" 640 641config DEBUG_OBJECTS 642 bool "Debug object operations" 643 depends on DEBUG_KERNEL 644 help 645 If you say Y here, additional code will be inserted into the 646 kernel to track the life time of various objects and validate 647 the operations on those objects. 648 649config DEBUG_OBJECTS_SELFTEST 650 bool "Debug objects selftest" 651 depends on DEBUG_OBJECTS 652 help 653 This enables the selftest of the object debug code. 654 655config DEBUG_OBJECTS_FREE 656 bool "Debug objects in freed memory" 657 depends on DEBUG_OBJECTS 658 help 659 This enables checks whether a k/v free operation frees an area 660 which contains an object which has not been deactivated 661 properly. This can make kmalloc/kfree-intensive workloads 662 much slower. 663 664config DEBUG_OBJECTS_TIMERS 665 bool "Debug timer objects" 666 depends on DEBUG_OBJECTS 667 help 668 If you say Y here, additional code will be inserted into the 669 timer routines to track the life time of timer objects and 670 validate the timer operations. 671 672config DEBUG_OBJECTS_WORK 673 bool "Debug work objects" 674 depends on DEBUG_OBJECTS 675 help 676 If you say Y here, additional code will be inserted into the 677 work queue routines to track the life time of work objects and 678 validate the work operations. 679 680config DEBUG_OBJECTS_RCU_HEAD 681 bool "Debug RCU callbacks objects" 682 depends on DEBUG_OBJECTS 683 help 684 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 685 686config DEBUG_OBJECTS_PERCPU_COUNTER 687 bool "Debug percpu counter objects" 688 depends on DEBUG_OBJECTS 689 help 690 If you say Y here, additional code will be inserted into the 691 percpu counter routines to track the life time of percpu counter 692 objects and validate the percpu counter operations. 693 694config DEBUG_OBJECTS_ENABLE_DEFAULT 695 int "debug_objects bootup default value (0-1)" 696 range 0 1 697 default "1" 698 depends on DEBUG_OBJECTS 699 help 700 Debug objects boot parameter default value 701 702config DEBUG_SLAB 703 bool "Debug slab memory allocations" 704 depends on DEBUG_KERNEL && SLAB 705 help 706 Say Y here to have the kernel do limited verification on memory 707 allocation as well as poisoning memory on free to catch use of freed 708 memory. This can make kmalloc/kfree-intensive workloads much slower. 709 710config SLUB_DEBUG_ON 711 bool "SLUB debugging on by default" 712 depends on SLUB && SLUB_DEBUG 713 default n 714 help 715 Boot with debugging on by default. SLUB boots by default with 716 the runtime debug capabilities switched off. Enabling this is 717 equivalent to specifying the "slub_debug" parameter on boot. 718 There is no support for more fine grained debug control like 719 possible with slub_debug=xxx. SLUB debugging may be switched 720 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 721 "slub_debug=-". 722 723config SLUB_STATS 724 default n 725 bool "Enable SLUB performance statistics" 726 depends on SLUB && SYSFS 727 help 728 SLUB statistics are useful to debug SLUBs allocation behavior in 729 order find ways to optimize the allocator. This should never be 730 enabled for production use since keeping statistics slows down 731 the allocator by a few percentage points. The slabinfo command 732 supports the determination of the most active slabs to figure 733 out which slabs are relevant to a particular load. 734 Try running: slabinfo -DA 735 736config HAVE_DEBUG_KMEMLEAK 737 bool 738 739config DEBUG_KMEMLEAK 740 bool "Kernel memory leak detector" 741 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 742 select DEBUG_FS 743 select STACKTRACE if STACKTRACE_SUPPORT 744 select KALLSYMS 745 select CRC32 746 help 747 Say Y here if you want to enable the memory leak 748 detector. The memory allocation/freeing is traced in a way 749 similar to the Boehm's conservative garbage collector, the 750 difference being that the orphan objects are not freed but 751 only shown in /sys/kernel/debug/kmemleak. Enabling this 752 feature will introduce an overhead to memory 753 allocations. See Documentation/dev-tools/kmemleak.rst for more 754 details. 755 756 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 757 of finding leaks due to the slab objects poisoning. 758 759 In order to access the kmemleak file, debugfs needs to be 760 mounted (usually at /sys/kernel/debug). 761 762config DEBUG_KMEMLEAK_MEM_POOL_SIZE 763 int "Kmemleak memory pool size" 764 depends on DEBUG_KMEMLEAK 765 range 200 1000000 766 default 16000 767 help 768 Kmemleak must track all the memory allocations to avoid 769 reporting false positives. Since memory may be allocated or 770 freed before kmemleak is fully initialised, use a static pool 771 of metadata objects to track such callbacks. After kmemleak is 772 fully initialised, this memory pool acts as an emergency one 773 if slab allocations fail. 774 775config DEBUG_KMEMLEAK_TEST 776 tristate "Simple test for the kernel memory leak detector" 777 depends on DEBUG_KMEMLEAK && m 778 help 779 This option enables a module that explicitly leaks memory. 780 781 If unsure, say N. 782 783config DEBUG_KMEMLEAK_DEFAULT_OFF 784 bool "Default kmemleak to off" 785 depends on DEBUG_KMEMLEAK 786 help 787 Say Y here to disable kmemleak by default. It can then be enabled 788 on the command line via kmemleak=on. 789 790config DEBUG_KMEMLEAK_AUTO_SCAN 791 bool "Enable kmemleak auto scan thread on boot up" 792 default y 793 depends on DEBUG_KMEMLEAK 794 help 795 Depending on the cpu, kmemleak scan may be cpu intensive and can 796 stall user tasks at times. This option enables/disables automatic 797 kmemleak scan at boot up. 798 799 Say N here to disable kmemleak auto scan thread to stop automatic 800 scanning. Disabling this option disables automatic reporting of 801 memory leaks. 802 803 If unsure, say Y. 804 805config DEBUG_STACK_USAGE 806 bool "Stack utilization instrumentation" 807 depends on DEBUG_KERNEL && !IA64 808 help 809 Enables the display of the minimum amount of free stack which each 810 task has ever had available in the sysrq-T and sysrq-P debug output. 811 812 This option will slow down process creation somewhat. 813 814config SCHED_STACK_END_CHECK 815 bool "Detect stack corruption on calls to schedule()" 816 depends on DEBUG_KERNEL 817 default n 818 help 819 This option checks for a stack overrun on calls to schedule(). 820 If the stack end location is found to be over written always panic as 821 the content of the corrupted region can no longer be trusted. 822 This is to ensure no erroneous behaviour occurs which could result in 823 data corruption or a sporadic crash at a later stage once the region 824 is examined. The runtime overhead introduced is minimal. 825 826config ARCH_HAS_DEBUG_VM_PGTABLE 827 bool 828 help 829 An architecture should select this when it can successfully 830 build and run DEBUG_VM_PGTABLE. 831 832config DEBUG_VM 833 bool "Debug VM" 834 depends on DEBUG_KERNEL 835 help 836 Enable this to turn on extended checks in the virtual-memory system 837 that may impact performance. 838 839 If unsure, say N. 840 841config DEBUG_VM_VMACACHE 842 bool "Debug VMA caching" 843 depends on DEBUG_VM 844 help 845 Enable this to turn on VMA caching debug information. Doing so 846 can cause significant overhead, so only enable it in non-production 847 environments. 848 849 If unsure, say N. 850 851config DEBUG_VM_RB 852 bool "Debug VM red-black trees" 853 depends on DEBUG_VM 854 help 855 Enable VM red-black tree debugging information and extra validations. 856 857 If unsure, say N. 858 859config DEBUG_VM_PGFLAGS 860 bool "Debug page-flags operations" 861 depends on DEBUG_VM 862 help 863 Enables extra validation on page flags operations. 864 865 If unsure, say N. 866 867config DEBUG_VM_PGTABLE 868 bool "Debug arch page table for semantics compliance" 869 depends on MMU 870 depends on ARCH_HAS_DEBUG_VM_PGTABLE 871 default y if DEBUG_VM 872 help 873 This option provides a debug method which can be used to test 874 architecture page table helper functions on various platforms in 875 verifying if they comply with expected generic MM semantics. This 876 will help architecture code in making sure that any changes or 877 new additions of these helpers still conform to expected 878 semantics of the generic MM. Platforms will have to opt in for 879 this through ARCH_HAS_DEBUG_VM_PGTABLE. 880 881 If unsure, say N. 882 883config ARCH_HAS_DEBUG_VIRTUAL 884 bool 885 886config DEBUG_VIRTUAL 887 bool "Debug VM translations" 888 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 889 help 890 Enable some costly sanity checks in virtual to page code. This can 891 catch mistakes with virt_to_page() and friends. 892 893 If unsure, say N. 894 895config DEBUG_NOMMU_REGIONS 896 bool "Debug the global anon/private NOMMU mapping region tree" 897 depends on DEBUG_KERNEL && !MMU 898 help 899 This option causes the global tree of anonymous and private mapping 900 regions to be regularly checked for invalid topology. 901 902config DEBUG_MEMORY_INIT 903 bool "Debug memory initialisation" if EXPERT 904 default !EXPERT 905 help 906 Enable this for additional checks during memory initialisation. 907 The sanity checks verify aspects of the VM such as the memory model 908 and other information provided by the architecture. Verbose 909 information will be printed at KERN_DEBUG loglevel depending 910 on the mminit_loglevel= command-line option. 911 912 If unsure, say Y 913 914config MEMORY_NOTIFIER_ERROR_INJECT 915 tristate "Memory hotplug notifier error injection module" 916 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 917 help 918 This option provides the ability to inject artificial errors to 919 memory hotplug notifier chain callbacks. It is controlled through 920 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 921 922 If the notifier call chain should be failed with some events 923 notified, write the error code to "actions/<notifier event>/error". 924 925 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 926 927 # cd /sys/kernel/debug/notifier-error-inject/memory 928 # echo -12 > actions/MEM_GOING_OFFLINE/error 929 # echo offline > /sys/devices/system/memory/memoryXXX/state 930 bash: echo: write error: Cannot allocate memory 931 932 To compile this code as a module, choose M here: the module will 933 be called memory-notifier-error-inject. 934 935 If unsure, say N. 936 937config DEBUG_PER_CPU_MAPS 938 bool "Debug access to per_cpu maps" 939 depends on DEBUG_KERNEL 940 depends on SMP 941 help 942 Say Y to verify that the per_cpu map being accessed has 943 been set up. This adds a fair amount of code to kernel memory 944 and decreases performance. 945 946 Say N if unsure. 947 948config DEBUG_KMAP_LOCAL 949 bool "Debug kmap_local temporary mappings" 950 depends on DEBUG_KERNEL && KMAP_LOCAL 951 help 952 This option enables additional error checking for the kmap_local 953 infrastructure. Disable for production use. 954 955config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 956 bool 957 958config DEBUG_KMAP_LOCAL_FORCE_MAP 959 bool "Enforce kmap_local temporary mappings" 960 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 961 select KMAP_LOCAL 962 select DEBUG_KMAP_LOCAL 963 help 964 This option enforces temporary mappings through the kmap_local 965 mechanism for non-highmem pages and on non-highmem systems. 966 Disable this for production systems! 967 968config DEBUG_HIGHMEM 969 bool "Highmem debugging" 970 depends on DEBUG_KERNEL && HIGHMEM 971 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 972 select DEBUG_KMAP_LOCAL 973 help 974 This option enables additional error checking for high memory 975 systems. Disable for production systems. 976 977config HAVE_DEBUG_STACKOVERFLOW 978 bool 979 980config DEBUG_STACKOVERFLOW 981 bool "Check for stack overflows" 982 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 983 help 984 Say Y here if you want to check for overflows of kernel, IRQ 985 and exception stacks (if your architecture uses them). This 986 option will show detailed messages if free stack space drops 987 below a certain limit. 988 989 These kinds of bugs usually occur when call-chains in the 990 kernel get too deep, especially when interrupts are 991 involved. 992 993 Use this in cases where you see apparently random memory 994 corruption, especially if it appears in 'struct thread_info' 995 996 If in doubt, say "N". 997 998source "lib/Kconfig.kasan" 999source "lib/Kconfig.kfence" 1000 1001endmenu # "Memory Debugging" 1002 1003config DEBUG_SHIRQ 1004 bool "Debug shared IRQ handlers" 1005 depends on DEBUG_KERNEL 1006 help 1007 Enable this to generate a spurious interrupt just before a shared 1008 interrupt handler is deregistered (generating one when registering 1009 is currently disabled). Drivers need to handle this correctly. Some 1010 don't and need to be caught. 1011 1012menu "Debug Oops, Lockups and Hangs" 1013 1014config PANIC_ON_OOPS 1015 bool "Panic on Oops" 1016 help 1017 Say Y here to enable the kernel to panic when it oopses. This 1018 has the same effect as setting oops=panic on the kernel command 1019 line. 1020 1021 This feature is useful to ensure that the kernel does not do 1022 anything erroneous after an oops which could result in data 1023 corruption or other issues. 1024 1025 Say N if unsure. 1026 1027config PANIC_ON_OOPS_VALUE 1028 int 1029 range 0 1 1030 default 0 if !PANIC_ON_OOPS 1031 default 1 if PANIC_ON_OOPS 1032 1033config PANIC_TIMEOUT 1034 int "panic timeout" 1035 default 0 1036 help 1037 Set the timeout value (in seconds) until a reboot occurs when 1038 the kernel panics. If n = 0, then we wait forever. A timeout 1039 value n > 0 will wait n seconds before rebooting, while a timeout 1040 value n < 0 will reboot immediately. 1041 1042config LOCKUP_DETECTOR 1043 bool 1044 1045config SOFTLOCKUP_DETECTOR 1046 bool "Detect Soft Lockups" 1047 depends on DEBUG_KERNEL && !S390 1048 select LOCKUP_DETECTOR 1049 help 1050 Say Y here to enable the kernel to act as a watchdog to detect 1051 soft lockups. 1052 1053 Softlockups are bugs that cause the kernel to loop in kernel 1054 mode for more than 20 seconds, without giving other tasks a 1055 chance to run. The current stack trace is displayed upon 1056 detection and the system will stay locked up. 1057 1058config BOOTPARAM_SOFTLOCKUP_PANIC 1059 bool "Panic (Reboot) On Soft Lockups" 1060 depends on SOFTLOCKUP_DETECTOR 1061 help 1062 Say Y here to enable the kernel to panic on "soft lockups", 1063 which are bugs that cause the kernel to loop in kernel 1064 mode for more than 20 seconds (configurable using the watchdog_thresh 1065 sysctl), without giving other tasks a chance to run. 1066 1067 The panic can be used in combination with panic_timeout, 1068 to cause the system to reboot automatically after a 1069 lockup has been detected. This feature is useful for 1070 high-availability systems that have uptime guarantees and 1071 where a lockup must be resolved ASAP. 1072 1073 Say N if unsure. 1074 1075config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 1076 int 1077 depends on SOFTLOCKUP_DETECTOR 1078 range 0 1 1079 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 1080 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 1081 1082config HARDLOCKUP_DETECTOR_PERF 1083 bool 1084 select SOFTLOCKUP_DETECTOR 1085 1086# 1087# Enables a timestamp based low pass filter to compensate for perf based 1088# hard lockup detection which runs too fast due to turbo modes. 1089# 1090config HARDLOCKUP_CHECK_TIMESTAMP 1091 bool 1092 1093# 1094# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1095# lockup detector rather than the perf based detector. 1096# 1097config HARDLOCKUP_DETECTOR 1098 bool "Detect Hard Lockups" 1099 depends on DEBUG_KERNEL && !S390 1100 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1101 select LOCKUP_DETECTOR 1102 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1103 help 1104 Say Y here to enable the kernel to act as a watchdog to detect 1105 hard lockups. 1106 1107 Hardlockups are bugs that cause the CPU to loop in kernel mode 1108 for more than 10 seconds, without letting other interrupts have a 1109 chance to run. The current stack trace is displayed upon detection 1110 and the system will stay locked up. 1111 1112config BOOTPARAM_HARDLOCKUP_PANIC 1113 bool "Panic (Reboot) On Hard Lockups" 1114 depends on HARDLOCKUP_DETECTOR 1115 help 1116 Say Y here to enable the kernel to panic on "hard lockups", 1117 which are bugs that cause the kernel to loop in kernel 1118 mode with interrupts disabled for more than 10 seconds (configurable 1119 using the watchdog_thresh sysctl). 1120 1121 Say N if unsure. 1122 1123config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1124 int 1125 depends on HARDLOCKUP_DETECTOR 1126 range 0 1 1127 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1128 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1129 1130config DETECT_HUNG_TASK 1131 bool "Detect Hung Tasks" 1132 depends on DEBUG_KERNEL 1133 default SOFTLOCKUP_DETECTOR 1134 help 1135 Say Y here to enable the kernel to detect "hung tasks", 1136 which are bugs that cause the task to be stuck in 1137 uninterruptible "D" state indefinitely. 1138 1139 When a hung task is detected, the kernel will print the 1140 current stack trace (which you should report), but the 1141 task will stay in uninterruptible state. If lockdep is 1142 enabled then all held locks will also be reported. This 1143 feature has negligible overhead. 1144 1145config DEFAULT_HUNG_TASK_TIMEOUT 1146 int "Default timeout for hung task detection (in seconds)" 1147 depends on DETECT_HUNG_TASK 1148 default 120 1149 help 1150 This option controls the default timeout (in seconds) used 1151 to determine when a task has become non-responsive and should 1152 be considered hung. 1153 1154 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1155 sysctl or by writing a value to 1156 /proc/sys/kernel/hung_task_timeout_secs. 1157 1158 A timeout of 0 disables the check. The default is two minutes. 1159 Keeping the default should be fine in most cases. 1160 1161config BOOTPARAM_HUNG_TASK_PANIC 1162 bool "Panic (Reboot) On Hung Tasks" 1163 depends on DETECT_HUNG_TASK 1164 help 1165 Say Y here to enable the kernel to panic on "hung tasks", 1166 which are bugs that cause the kernel to leave a task stuck 1167 in uninterruptible "D" state. 1168 1169 The panic can be used in combination with panic_timeout, 1170 to cause the system to reboot automatically after a 1171 hung task has been detected. This feature is useful for 1172 high-availability systems that have uptime guarantees and 1173 where a hung tasks must be resolved ASAP. 1174 1175 Say N if unsure. 1176 1177config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1178 int 1179 depends on DETECT_HUNG_TASK 1180 range 0 1 1181 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1182 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1183 1184config WQ_WATCHDOG 1185 bool "Detect Workqueue Stalls" 1186 depends on DEBUG_KERNEL 1187 help 1188 Say Y here to enable stall detection on workqueues. If a 1189 worker pool doesn't make forward progress on a pending work 1190 item for over a given amount of time, 30s by default, a 1191 warning message is printed along with dump of workqueue 1192 state. This can be configured through kernel parameter 1193 "workqueue.watchdog_thresh" and its sysfs counterpart. 1194 1195config TEST_LOCKUP 1196 tristate "Test module to generate lockups" 1197 depends on m 1198 help 1199 This builds the "test_lockup" module that helps to make sure 1200 that watchdogs and lockup detectors are working properly. 1201 1202 Depending on module parameters it could emulate soft or hard 1203 lockup, "hung task", or locking arbitrary lock for a long time. 1204 Also it could generate series of lockups with cooling-down periods. 1205 1206 If unsure, say N. 1207 1208endmenu # "Debug lockups and hangs" 1209 1210menu "Scheduler Debugging" 1211 1212config SCHED_DEBUG 1213 bool "Collect scheduler debugging info" 1214 depends on DEBUG_KERNEL && PROC_FS 1215 default y 1216 help 1217 If you say Y here, the /proc/sched_debug file will be provided 1218 that can help debug the scheduler. The runtime overhead of this 1219 option is minimal. 1220 1221config SCHED_INFO 1222 bool 1223 default n 1224 1225config SCHEDSTATS 1226 bool "Collect scheduler statistics" 1227 depends on DEBUG_KERNEL && PROC_FS 1228 select SCHED_INFO 1229 help 1230 If you say Y here, additional code will be inserted into the 1231 scheduler and related routines to collect statistics about 1232 scheduler behavior and provide them in /proc/schedstat. These 1233 stats may be useful for both tuning and debugging the scheduler 1234 If you aren't debugging the scheduler or trying to tune a specific 1235 application, you can say N to avoid the very slight overhead 1236 this adds. 1237 1238endmenu 1239 1240config DEBUG_TIMEKEEPING 1241 bool "Enable extra timekeeping sanity checking" 1242 help 1243 This option will enable additional timekeeping sanity checks 1244 which may be helpful when diagnosing issues where timekeeping 1245 problems are suspected. 1246 1247 This may include checks in the timekeeping hotpaths, so this 1248 option may have a (very small) performance impact to some 1249 workloads. 1250 1251 If unsure, say N. 1252 1253config DEBUG_PREEMPT 1254 bool "Debug preemptible kernel" 1255 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1256 default y 1257 help 1258 If you say Y here then the kernel will use a debug variant of the 1259 commonly used smp_processor_id() function and will print warnings 1260 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1261 will detect preemption count underflows. 1262 1263menu "Lock Debugging (spinlocks, mutexes, etc...)" 1264 1265config LOCK_DEBUGGING_SUPPORT 1266 bool 1267 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1268 default y 1269 1270config PROVE_LOCKING 1271 bool "Lock debugging: prove locking correctness" 1272 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1273 select LOCKDEP 1274 select DEBUG_SPINLOCK 1275 select DEBUG_MUTEXES if !PREEMPT_RT 1276 select DEBUG_RT_MUTEXES if RT_MUTEXES 1277 select DEBUG_RWSEMS 1278 select DEBUG_WW_MUTEX_SLOWPATH 1279 select DEBUG_LOCK_ALLOC 1280 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1281 select TRACE_IRQFLAGS 1282 default n 1283 help 1284 This feature enables the kernel to prove that all locking 1285 that occurs in the kernel runtime is mathematically 1286 correct: that under no circumstance could an arbitrary (and 1287 not yet triggered) combination of observed locking 1288 sequences (on an arbitrary number of CPUs, running an 1289 arbitrary number of tasks and interrupt contexts) cause a 1290 deadlock. 1291 1292 In short, this feature enables the kernel to report locking 1293 related deadlocks before they actually occur. 1294 1295 The proof does not depend on how hard and complex a 1296 deadlock scenario would be to trigger: how many 1297 participant CPUs, tasks and irq-contexts would be needed 1298 for it to trigger. The proof also does not depend on 1299 timing: if a race and a resulting deadlock is possible 1300 theoretically (no matter how unlikely the race scenario 1301 is), it will be proven so and will immediately be 1302 reported by the kernel (once the event is observed that 1303 makes the deadlock theoretically possible). 1304 1305 If a deadlock is impossible (i.e. the locking rules, as 1306 observed by the kernel, are mathematically correct), the 1307 kernel reports nothing. 1308 1309 NOTE: this feature can also be enabled for rwlocks, mutexes 1310 and rwsems - in which case all dependencies between these 1311 different locking variants are observed and mapped too, and 1312 the proof of observed correctness is also maintained for an 1313 arbitrary combination of these separate locking variants. 1314 1315 For more details, see Documentation/locking/lockdep-design.rst. 1316 1317config PROVE_RAW_LOCK_NESTING 1318 bool "Enable raw_spinlock - spinlock nesting checks" 1319 depends on PROVE_LOCKING 1320 default n 1321 help 1322 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1323 that the lock nesting rules for PREEMPT_RT enabled kernels are 1324 not violated. 1325 1326 NOTE: There are known nesting problems. So if you enable this 1327 option expect lockdep splats until these problems have been fully 1328 addressed which is work in progress. This config switch allows to 1329 identify and analyze these problems. It will be removed and the 1330 check permanently enabled once the main issues have been fixed. 1331 1332 If unsure, select N. 1333 1334config LOCK_STAT 1335 bool "Lock usage statistics" 1336 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1337 select LOCKDEP 1338 select DEBUG_SPINLOCK 1339 select DEBUG_MUTEXES if !PREEMPT_RT 1340 select DEBUG_RT_MUTEXES if RT_MUTEXES 1341 select DEBUG_LOCK_ALLOC 1342 default n 1343 help 1344 This feature enables tracking lock contention points 1345 1346 For more details, see Documentation/locking/lockstat.rst 1347 1348 This also enables lock events required by "perf lock", 1349 subcommand of perf. 1350 If you want to use "perf lock", you also need to turn on 1351 CONFIG_EVENT_TRACING. 1352 1353 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1354 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1355 1356config DEBUG_RT_MUTEXES 1357 bool "RT Mutex debugging, deadlock detection" 1358 depends on DEBUG_KERNEL && RT_MUTEXES 1359 help 1360 This allows rt mutex semantics violations and rt mutex related 1361 deadlocks (lockups) to be detected and reported automatically. 1362 1363config DEBUG_SPINLOCK 1364 bool "Spinlock and rw-lock debugging: basic checks" 1365 depends on DEBUG_KERNEL 1366 select UNINLINE_SPIN_UNLOCK 1367 help 1368 Say Y here and build SMP to catch missing spinlock initialization 1369 and certain other kinds of spinlock errors commonly made. This is 1370 best used in conjunction with the NMI watchdog so that spinlock 1371 deadlocks are also debuggable. 1372 1373config DEBUG_MUTEXES 1374 bool "Mutex debugging: basic checks" 1375 depends on DEBUG_KERNEL && !PREEMPT_RT 1376 help 1377 This feature allows mutex semantics violations to be detected and 1378 reported. 1379 1380config DEBUG_WW_MUTEX_SLOWPATH 1381 bool "Wait/wound mutex debugging: Slowpath testing" 1382 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1383 select DEBUG_LOCK_ALLOC 1384 select DEBUG_SPINLOCK 1385 select DEBUG_MUTEXES if !PREEMPT_RT 1386 select DEBUG_RT_MUTEXES if PREEMPT_RT 1387 help 1388 This feature enables slowpath testing for w/w mutex users by 1389 injecting additional -EDEADLK wound/backoff cases. Together with 1390 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1391 will test all possible w/w mutex interface abuse with the 1392 exception of simply not acquiring all the required locks. 1393 Note that this feature can introduce significant overhead, so 1394 it really should not be enabled in a production or distro kernel, 1395 even a debug kernel. If you are a driver writer, enable it. If 1396 you are a distro, do not. 1397 1398config DEBUG_RWSEMS 1399 bool "RW Semaphore debugging: basic checks" 1400 depends on DEBUG_KERNEL 1401 help 1402 This debugging feature allows mismatched rw semaphore locks 1403 and unlocks to be detected and reported. 1404 1405config DEBUG_LOCK_ALLOC 1406 bool "Lock debugging: detect incorrect freeing of live locks" 1407 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1408 select DEBUG_SPINLOCK 1409 select DEBUG_MUTEXES if !PREEMPT_RT 1410 select DEBUG_RT_MUTEXES if RT_MUTEXES 1411 select LOCKDEP 1412 help 1413 This feature will check whether any held lock (spinlock, rwlock, 1414 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1415 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1416 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1417 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1418 held during task exit. 1419 1420config LOCKDEP 1421 bool 1422 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1423 select STACKTRACE 1424 select KALLSYMS 1425 select KALLSYMS_ALL 1426 1427config LOCKDEP_SMALL 1428 bool 1429 1430config LOCKDEP_BITS 1431 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1432 depends on LOCKDEP && !LOCKDEP_SMALL 1433 range 10 30 1434 default 15 1435 help 1436 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1437 1438config LOCKDEP_CHAINS_BITS 1439 int "Bitsize for MAX_LOCKDEP_CHAINS" 1440 depends on LOCKDEP && !LOCKDEP_SMALL 1441 range 10 30 1442 default 16 1443 help 1444 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1445 1446config LOCKDEP_STACK_TRACE_BITS 1447 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1448 depends on LOCKDEP && !LOCKDEP_SMALL 1449 range 10 30 1450 default 19 1451 help 1452 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1453 1454config LOCKDEP_STACK_TRACE_HASH_BITS 1455 int "Bitsize for STACK_TRACE_HASH_SIZE" 1456 depends on LOCKDEP && !LOCKDEP_SMALL 1457 range 10 30 1458 default 14 1459 help 1460 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1461 1462config LOCKDEP_CIRCULAR_QUEUE_BITS 1463 int "Bitsize for elements in circular_queue struct" 1464 depends on LOCKDEP 1465 range 10 30 1466 default 12 1467 help 1468 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1469 1470config DEBUG_LOCKDEP 1471 bool "Lock dependency engine debugging" 1472 depends on DEBUG_KERNEL && LOCKDEP 1473 select DEBUG_IRQFLAGS 1474 help 1475 If you say Y here, the lock dependency engine will do 1476 additional runtime checks to debug itself, at the price 1477 of more runtime overhead. 1478 1479config DEBUG_ATOMIC_SLEEP 1480 bool "Sleep inside atomic section checking" 1481 select PREEMPT_COUNT 1482 depends on DEBUG_KERNEL 1483 depends on !ARCH_NO_PREEMPT 1484 help 1485 If you say Y here, various routines which may sleep will become very 1486 noisy if they are called inside atomic sections: when a spinlock is 1487 held, inside an rcu read side critical section, inside preempt disabled 1488 sections, inside an interrupt, etc... 1489 1490config DEBUG_LOCKING_API_SELFTESTS 1491 bool "Locking API boot-time self-tests" 1492 depends on DEBUG_KERNEL 1493 help 1494 Say Y here if you want the kernel to run a short self-test during 1495 bootup. The self-test checks whether common types of locking bugs 1496 are detected by debugging mechanisms or not. (if you disable 1497 lock debugging then those bugs won't be detected of course.) 1498 The following locking APIs are covered: spinlocks, rwlocks, 1499 mutexes and rwsems. 1500 1501config LOCK_TORTURE_TEST 1502 tristate "torture tests for locking" 1503 depends on DEBUG_KERNEL 1504 select TORTURE_TEST 1505 help 1506 This option provides a kernel module that runs torture tests 1507 on kernel locking primitives. The kernel module may be built 1508 after the fact on the running kernel to be tested, if desired. 1509 1510 Say Y here if you want kernel locking-primitive torture tests 1511 to be built into the kernel. 1512 Say M if you want these torture tests to build as a module. 1513 Say N if you are unsure. 1514 1515config WW_MUTEX_SELFTEST 1516 tristate "Wait/wound mutex selftests" 1517 help 1518 This option provides a kernel module that runs tests on the 1519 on the struct ww_mutex locking API. 1520 1521 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1522 with this test harness. 1523 1524 Say M if you want these self tests to build as a module. 1525 Say N if you are unsure. 1526 1527config SCF_TORTURE_TEST 1528 tristate "torture tests for smp_call_function*()" 1529 depends on DEBUG_KERNEL 1530 select TORTURE_TEST 1531 help 1532 This option provides a kernel module that runs torture tests 1533 on the smp_call_function() family of primitives. The kernel 1534 module may be built after the fact on the running kernel to 1535 be tested, if desired. 1536 1537config CSD_LOCK_WAIT_DEBUG 1538 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1539 depends on DEBUG_KERNEL 1540 depends on 64BIT 1541 default n 1542 help 1543 This option enables debug prints when CPUs are slow to respond 1544 to the smp_call_function*() IPI wrappers. These debug prints 1545 include the IPI handler function currently executing (if any) 1546 and relevant stack traces. 1547 1548choice 1549 prompt "Lock debugging: prove subsystem device_lock() correctness" 1550 depends on PROVE_LOCKING 1551 help 1552 For subsystems that have instrumented their usage of the device_lock() 1553 with nested annotations, enable lock dependency checking. The locking 1554 hierarchy 'subclass' identifiers are not compatible across 1555 sub-systems, so only one can be enabled at a time. 1556 1557config PROVE_NVDIMM_LOCKING 1558 bool "NVDIMM" 1559 depends on LIBNVDIMM 1560 help 1561 Enable lockdep to validate nd_device_lock() usage. 1562 1563config PROVE_CXL_LOCKING 1564 bool "CXL" 1565 depends on CXL_BUS 1566 help 1567 Enable lockdep to validate cxl_device_lock() usage. 1568 1569endchoice 1570 1571endmenu # lock debugging 1572 1573config TRACE_IRQFLAGS 1574 depends on TRACE_IRQFLAGS_SUPPORT 1575 bool 1576 help 1577 Enables hooks to interrupt enabling and disabling for 1578 either tracing or lock debugging. 1579 1580config TRACE_IRQFLAGS_NMI 1581 def_bool y 1582 depends on TRACE_IRQFLAGS 1583 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1584 1585config DEBUG_IRQFLAGS 1586 bool "Debug IRQ flag manipulation" 1587 help 1588 Enables checks for potentially unsafe enabling or disabling of 1589 interrupts, such as calling raw_local_irq_restore() when interrupts 1590 are enabled. 1591 1592config STACKTRACE 1593 bool "Stack backtrace support" 1594 depends on STACKTRACE_SUPPORT 1595 help 1596 This option causes the kernel to create a /proc/pid/stack for 1597 every process, showing its current stack trace. 1598 It is also used by various kernel debugging features that require 1599 stack trace generation. 1600 1601config WARN_ALL_UNSEEDED_RANDOM 1602 bool "Warn for all uses of unseeded randomness" 1603 default n 1604 help 1605 Some parts of the kernel contain bugs relating to their use of 1606 cryptographically secure random numbers before it's actually possible 1607 to generate those numbers securely. This setting ensures that these 1608 flaws don't go unnoticed, by enabling a message, should this ever 1609 occur. This will allow people with obscure setups to know when things 1610 are going wrong, so that they might contact developers about fixing 1611 it. 1612 1613 Unfortunately, on some models of some architectures getting 1614 a fully seeded CRNG is extremely difficult, and so this can 1615 result in dmesg getting spammed for a surprisingly long 1616 time. This is really bad from a security perspective, and 1617 so architecture maintainers really need to do what they can 1618 to get the CRNG seeded sooner after the system is booted. 1619 However, since users cannot do anything actionable to 1620 address this, by default this option is disabled. 1621 1622 Say Y here if you want to receive warnings for all uses of 1623 unseeded randomness. This will be of use primarily for 1624 those developers interested in improving the security of 1625 Linux kernels running on their architecture (or 1626 subarchitecture). 1627 1628config DEBUG_KOBJECT 1629 bool "kobject debugging" 1630 depends on DEBUG_KERNEL 1631 help 1632 If you say Y here, some extra kobject debugging messages will be sent 1633 to the syslog. 1634 1635config DEBUG_KOBJECT_RELEASE 1636 bool "kobject release debugging" 1637 depends on DEBUG_OBJECTS_TIMERS 1638 help 1639 kobjects are reference counted objects. This means that their 1640 last reference count put is not predictable, and the kobject can 1641 live on past the point at which a driver decides to drop it's 1642 initial reference to the kobject gained on allocation. An 1643 example of this would be a struct device which has just been 1644 unregistered. 1645 1646 However, some buggy drivers assume that after such an operation, 1647 the memory backing the kobject can be immediately freed. This 1648 goes completely against the principles of a refcounted object. 1649 1650 If you say Y here, the kernel will delay the release of kobjects 1651 on the last reference count to improve the visibility of this 1652 kind of kobject release bug. 1653 1654config HAVE_DEBUG_BUGVERBOSE 1655 bool 1656 1657menu "Debug kernel data structures" 1658 1659config DEBUG_LIST 1660 bool "Debug linked list manipulation" 1661 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1662 help 1663 Enable this to turn on extended checks in the linked-list 1664 walking routines. 1665 1666 If unsure, say N. 1667 1668config DEBUG_PLIST 1669 bool "Debug priority linked list manipulation" 1670 depends on DEBUG_KERNEL 1671 help 1672 Enable this to turn on extended checks in the priority-ordered 1673 linked-list (plist) walking routines. This checks the entire 1674 list multiple times during each manipulation. 1675 1676 If unsure, say N. 1677 1678config DEBUG_SG 1679 bool "Debug SG table operations" 1680 depends on DEBUG_KERNEL 1681 help 1682 Enable this to turn on checks on scatter-gather tables. This can 1683 help find problems with drivers that do not properly initialize 1684 their sg tables. 1685 1686 If unsure, say N. 1687 1688config DEBUG_NOTIFIERS 1689 bool "Debug notifier call chains" 1690 depends on DEBUG_KERNEL 1691 help 1692 Enable this to turn on sanity checking for notifier call chains. 1693 This is most useful for kernel developers to make sure that 1694 modules properly unregister themselves from notifier chains. 1695 This is a relatively cheap check but if you care about maximum 1696 performance, say N. 1697 1698config BUG_ON_DATA_CORRUPTION 1699 bool "Trigger a BUG when data corruption is detected" 1700 select DEBUG_LIST 1701 help 1702 Select this option if the kernel should BUG when it encounters 1703 data corruption in kernel memory structures when they get checked 1704 for validity. 1705 1706 If unsure, say N. 1707 1708endmenu 1709 1710config DEBUG_CREDENTIALS 1711 bool "Debug credential management" 1712 depends on DEBUG_KERNEL 1713 help 1714 Enable this to turn on some debug checking for credential 1715 management. The additional code keeps track of the number of 1716 pointers from task_structs to any given cred struct, and checks to 1717 see that this number never exceeds the usage count of the cred 1718 struct. 1719 1720 Furthermore, if SELinux is enabled, this also checks that the 1721 security pointer in the cred struct is never seen to be invalid. 1722 1723 If unsure, say N. 1724 1725source "kernel/rcu/Kconfig.debug" 1726 1727config DEBUG_WQ_FORCE_RR_CPU 1728 bool "Force round-robin CPU selection for unbound work items" 1729 depends on DEBUG_KERNEL 1730 default n 1731 help 1732 Workqueue used to implicitly guarantee that work items queued 1733 without explicit CPU specified are put on the local CPU. This 1734 guarantee is no longer true and while local CPU is still 1735 preferred work items may be put on foreign CPUs. Kernel 1736 parameter "workqueue.debug_force_rr_cpu" is added to force 1737 round-robin CPU selection to flush out usages which depend on the 1738 now broken guarantee. This config option enables the debug 1739 feature by default. When enabled, memory and cache locality will 1740 be impacted. 1741 1742config CPU_HOTPLUG_STATE_CONTROL 1743 bool "Enable CPU hotplug state control" 1744 depends on DEBUG_KERNEL 1745 depends on HOTPLUG_CPU 1746 default n 1747 help 1748 Allows to write steps between "offline" and "online" to the CPUs 1749 sysfs target file so states can be stepped granular. This is a debug 1750 option for now as the hotplug machinery cannot be stopped and 1751 restarted at arbitrary points yet. 1752 1753 Say N if your are unsure. 1754 1755config LATENCYTOP 1756 bool "Latency measuring infrastructure" 1757 depends on DEBUG_KERNEL 1758 depends on STACKTRACE_SUPPORT 1759 depends on PROC_FS 1760 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1761 select KALLSYMS 1762 select KALLSYMS_ALL 1763 select STACKTRACE 1764 select SCHEDSTATS 1765 help 1766 Enable this option if you want to use the LatencyTOP tool 1767 to find out which userspace is blocking on what kernel operations. 1768 1769source "kernel/trace/Kconfig" 1770 1771config PROVIDE_OHCI1394_DMA_INIT 1772 bool "Remote debugging over FireWire early on boot" 1773 depends on PCI && X86 1774 help 1775 If you want to debug problems which hang or crash the kernel early 1776 on boot and the crashing machine has a FireWire port, you can use 1777 this feature to remotely access the memory of the crashed machine 1778 over FireWire. This employs remote DMA as part of the OHCI1394 1779 specification which is now the standard for FireWire controllers. 1780 1781 With remote DMA, you can monitor the printk buffer remotely using 1782 firescope and access all memory below 4GB using fireproxy from gdb. 1783 Even controlling a kernel debugger is possible using remote DMA. 1784 1785 Usage: 1786 1787 If ohci1394_dma=early is used as boot parameter, it will initialize 1788 all OHCI1394 controllers which are found in the PCI config space. 1789 1790 As all changes to the FireWire bus such as enabling and disabling 1791 devices cause a bus reset and thereby disable remote DMA for all 1792 devices, be sure to have the cable plugged and FireWire enabled on 1793 the debugging host before booting the debug target for debugging. 1794 1795 This code (~1k) is freed after boot. By then, the firewire stack 1796 in charge of the OHCI-1394 controllers should be used instead. 1797 1798 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1799 1800source "samples/Kconfig" 1801 1802config ARCH_HAS_DEVMEM_IS_ALLOWED 1803 bool 1804 1805config STRICT_DEVMEM 1806 bool "Filter access to /dev/mem" 1807 depends on MMU && DEVMEM 1808 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1809 default y if PPC || X86 || ARM64 1810 help 1811 If this option is disabled, you allow userspace (root) access to all 1812 of memory, including kernel and userspace memory. Accidental 1813 access to this is obviously disastrous, but specific access can 1814 be used by people debugging the kernel. Note that with PAT support 1815 enabled, even in this case there are restrictions on /dev/mem 1816 use due to the cache aliasing requirements. 1817 1818 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1819 file only allows userspace access to PCI space and the BIOS code and 1820 data regions. This is sufficient for dosemu and X and all common 1821 users of /dev/mem. 1822 1823 If in doubt, say Y. 1824 1825config IO_STRICT_DEVMEM 1826 bool "Filter I/O access to /dev/mem" 1827 depends on STRICT_DEVMEM 1828 help 1829 If this option is disabled, you allow userspace (root) access to all 1830 io-memory regardless of whether a driver is actively using that 1831 range. Accidental access to this is obviously disastrous, but 1832 specific access can be used by people debugging kernel drivers. 1833 1834 If this option is switched on, the /dev/mem file only allows 1835 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1836 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1837 if the driver using a given range cannot be disabled. 1838 1839 If in doubt, say Y. 1840 1841menu "$(SRCARCH) Debugging" 1842 1843source "arch/$(SRCARCH)/Kconfig.debug" 1844 1845endmenu 1846 1847menu "Kernel Testing and Coverage" 1848 1849source "lib/kunit/Kconfig" 1850 1851config NOTIFIER_ERROR_INJECTION 1852 tristate "Notifier error injection" 1853 depends on DEBUG_KERNEL 1854 select DEBUG_FS 1855 help 1856 This option provides the ability to inject artificial errors to 1857 specified notifier chain callbacks. It is useful to test the error 1858 handling of notifier call chain failures. 1859 1860 Say N if unsure. 1861 1862config PM_NOTIFIER_ERROR_INJECT 1863 tristate "PM notifier error injection module" 1864 depends on PM && NOTIFIER_ERROR_INJECTION 1865 default m if PM_DEBUG 1866 help 1867 This option provides the ability to inject artificial errors to 1868 PM notifier chain callbacks. It is controlled through debugfs 1869 interface /sys/kernel/debug/notifier-error-inject/pm 1870 1871 If the notifier call chain should be failed with some events 1872 notified, write the error code to "actions/<notifier event>/error". 1873 1874 Example: Inject PM suspend error (-12 = -ENOMEM) 1875 1876 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1877 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1878 # echo mem > /sys/power/state 1879 bash: echo: write error: Cannot allocate memory 1880 1881 To compile this code as a module, choose M here: the module will 1882 be called pm-notifier-error-inject. 1883 1884 If unsure, say N. 1885 1886config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1887 tristate "OF reconfig notifier error injection module" 1888 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1889 help 1890 This option provides the ability to inject artificial errors to 1891 OF reconfig notifier chain callbacks. It is controlled 1892 through debugfs interface under 1893 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1894 1895 If the notifier call chain should be failed with some events 1896 notified, write the error code to "actions/<notifier event>/error". 1897 1898 To compile this code as a module, choose M here: the module will 1899 be called of-reconfig-notifier-error-inject. 1900 1901 If unsure, say N. 1902 1903config NETDEV_NOTIFIER_ERROR_INJECT 1904 tristate "Netdev notifier error injection module" 1905 depends on NET && NOTIFIER_ERROR_INJECTION 1906 help 1907 This option provides the ability to inject artificial errors to 1908 netdevice notifier chain callbacks. It is controlled through debugfs 1909 interface /sys/kernel/debug/notifier-error-inject/netdev 1910 1911 If the notifier call chain should be failed with some events 1912 notified, write the error code to "actions/<notifier event>/error". 1913 1914 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1915 1916 # cd /sys/kernel/debug/notifier-error-inject/netdev 1917 # echo -22 > actions/NETDEV_CHANGEMTU/error 1918 # ip link set eth0 mtu 1024 1919 RTNETLINK answers: Invalid argument 1920 1921 To compile this code as a module, choose M here: the module will 1922 be called netdev-notifier-error-inject. 1923 1924 If unsure, say N. 1925 1926config FUNCTION_ERROR_INJECTION 1927 def_bool y 1928 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1929 1930config FAULT_INJECTION 1931 bool "Fault-injection framework" 1932 depends on DEBUG_KERNEL 1933 help 1934 Provide fault-injection framework. 1935 For more details, see Documentation/fault-injection/. 1936 1937config FAILSLAB 1938 bool "Fault-injection capability for kmalloc" 1939 depends on FAULT_INJECTION 1940 depends on SLAB || SLUB 1941 help 1942 Provide fault-injection capability for kmalloc. 1943 1944config FAIL_PAGE_ALLOC 1945 bool "Fault-injection capability for alloc_pages()" 1946 depends on FAULT_INJECTION 1947 help 1948 Provide fault-injection capability for alloc_pages(). 1949 1950config FAULT_INJECTION_USERCOPY 1951 bool "Fault injection capability for usercopy functions" 1952 depends on FAULT_INJECTION 1953 help 1954 Provides fault-injection capability to inject failures 1955 in usercopy functions (copy_from_user(), get_user(), ...). 1956 1957config FAIL_MAKE_REQUEST 1958 bool "Fault-injection capability for disk IO" 1959 depends on FAULT_INJECTION && BLOCK 1960 help 1961 Provide fault-injection capability for disk IO. 1962 1963config FAIL_IO_TIMEOUT 1964 bool "Fault-injection capability for faking disk interrupts" 1965 depends on FAULT_INJECTION && BLOCK 1966 help 1967 Provide fault-injection capability on end IO handling. This 1968 will make the block layer "forget" an interrupt as configured, 1969 thus exercising the error handling. 1970 1971 Only works with drivers that use the generic timeout handling, 1972 for others it won't do anything. 1973 1974config FAIL_FUTEX 1975 bool "Fault-injection capability for futexes" 1976 select DEBUG_FS 1977 depends on FAULT_INJECTION && FUTEX 1978 help 1979 Provide fault-injection capability for futexes. 1980 1981config FAULT_INJECTION_DEBUG_FS 1982 bool "Debugfs entries for fault-injection capabilities" 1983 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1984 help 1985 Enable configuration of fault-injection capabilities via debugfs. 1986 1987config FAIL_FUNCTION 1988 bool "Fault-injection capability for functions" 1989 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1990 help 1991 Provide function-based fault-injection capability. 1992 This will allow you to override a specific function with a return 1993 with given return value. As a result, function caller will see 1994 an error value and have to handle it. This is useful to test the 1995 error handling in various subsystems. 1996 1997config FAIL_MMC_REQUEST 1998 bool "Fault-injection capability for MMC IO" 1999 depends on FAULT_INJECTION_DEBUG_FS && MMC 2000 help 2001 Provide fault-injection capability for MMC IO. 2002 This will make the mmc core return data errors. This is 2003 useful to test the error handling in the mmc block device 2004 and to test how the mmc host driver handles retries from 2005 the block device. 2006 2007config FAIL_SUNRPC 2008 bool "Fault-injection capability for SunRPC" 2009 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2010 help 2011 Provide fault-injection capability for SunRPC and 2012 its consumers. 2013 2014config FAULT_INJECTION_STACKTRACE_FILTER 2015 bool "stacktrace filter for fault-injection capabilities" 2016 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 2017 depends on !X86_64 2018 select STACKTRACE 2019 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2020 help 2021 Provide stacktrace filter for fault-injection capabilities 2022 2023config ARCH_HAS_KCOV 2024 bool 2025 help 2026 An architecture should select this when it can successfully 2027 build and run with CONFIG_KCOV. This typically requires 2028 disabling instrumentation for some early boot code. 2029 2030config CC_HAS_SANCOV_TRACE_PC 2031 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2032 2033 2034config KCOV 2035 bool "Code coverage for fuzzing" 2036 depends on ARCH_HAS_KCOV 2037 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2038 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2039 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2040 select DEBUG_FS 2041 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2042 select OBJTOOL if HAVE_NOINSTR_HACK 2043 help 2044 KCOV exposes kernel code coverage information in a form suitable 2045 for coverage-guided fuzzing (randomized testing). 2046 2047 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2048 different machines and across reboots. If you need stable PC values, 2049 disable RANDOMIZE_BASE. 2050 2051 For more details, see Documentation/dev-tools/kcov.rst. 2052 2053config KCOV_ENABLE_COMPARISONS 2054 bool "Enable comparison operands collection by KCOV" 2055 depends on KCOV 2056 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2057 help 2058 KCOV also exposes operands of every comparison in the instrumented 2059 code along with operand sizes and PCs of the comparison instructions. 2060 These operands can be used by fuzzing engines to improve the quality 2061 of fuzzing coverage. 2062 2063config KCOV_INSTRUMENT_ALL 2064 bool "Instrument all code by default" 2065 depends on KCOV 2066 default y 2067 help 2068 If you are doing generic system call fuzzing (like e.g. syzkaller), 2069 then you will want to instrument the whole kernel and you should 2070 say y here. If you are doing more targeted fuzzing (like e.g. 2071 filesystem fuzzing with AFL) then you will want to enable coverage 2072 for more specific subsets of files, and should say n here. 2073 2074config KCOV_IRQ_AREA_SIZE 2075 hex "Size of interrupt coverage collection area in words" 2076 depends on KCOV 2077 default 0x40000 2078 help 2079 KCOV uses preallocated per-cpu areas to collect coverage from 2080 soft interrupts. This specifies the size of those areas in the 2081 number of unsigned long words. 2082 2083menuconfig RUNTIME_TESTING_MENU 2084 bool "Runtime Testing" 2085 def_bool y 2086 2087if RUNTIME_TESTING_MENU 2088 2089config LKDTM 2090 tristate "Linux Kernel Dump Test Tool Module" 2091 depends on DEBUG_FS 2092 help 2093 This module enables testing of the different dumping mechanisms by 2094 inducing system failures at predefined crash points. 2095 If you don't need it: say N 2096 Choose M here to compile this code as a module. The module will be 2097 called lkdtm. 2098 2099 Documentation on how to use the module can be found in 2100 Documentation/fault-injection/provoke-crashes.rst 2101 2102config TEST_LIST_SORT 2103 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2104 depends on KUNIT 2105 default KUNIT_ALL_TESTS 2106 help 2107 Enable this to turn on 'list_sort()' function test. This test is 2108 executed only once during system boot (so affects only boot time), 2109 or at module load time. 2110 2111 If unsure, say N. 2112 2113config TEST_MIN_HEAP 2114 tristate "Min heap test" 2115 depends on DEBUG_KERNEL || m 2116 help 2117 Enable this to turn on min heap function tests. This test is 2118 executed only once during system boot (so affects only boot time), 2119 or at module load time. 2120 2121 If unsure, say N. 2122 2123config TEST_SORT 2124 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2125 depends on KUNIT 2126 default KUNIT_ALL_TESTS 2127 help 2128 This option enables the self-test function of 'sort()' at boot, 2129 or at module load time. 2130 2131 If unsure, say N. 2132 2133config TEST_DIV64 2134 tristate "64bit/32bit division and modulo test" 2135 depends on DEBUG_KERNEL || m 2136 help 2137 Enable this to turn on 'do_div()' function test. This test is 2138 executed only once during system boot (so affects only boot time), 2139 or at module load time. 2140 2141 If unsure, say N. 2142 2143config KPROBES_SANITY_TEST 2144 tristate "Kprobes sanity tests" 2145 depends on DEBUG_KERNEL 2146 depends on KPROBES 2147 depends on KUNIT 2148 help 2149 This option provides for testing basic kprobes functionality on 2150 boot. Samples of kprobe and kretprobe are inserted and 2151 verified for functionality. 2152 2153 Say N if you are unsure. 2154 2155config FPROBE_SANITY_TEST 2156 bool "Self test for fprobe" 2157 depends on DEBUG_KERNEL 2158 depends on FPROBE 2159 depends on KUNIT=y 2160 help 2161 This option will enable testing the fprobe when the system boot. 2162 A series of tests are made to verify that the fprobe is functioning 2163 properly. 2164 2165 Say N if you are unsure. 2166 2167config BACKTRACE_SELF_TEST 2168 tristate "Self test for the backtrace code" 2169 depends on DEBUG_KERNEL 2170 help 2171 This option provides a kernel module that can be used to test 2172 the kernel stack backtrace code. This option is not useful 2173 for distributions or general kernels, but only for kernel 2174 developers working on architecture code. 2175 2176 Note that if you want to also test saved backtraces, you will 2177 have to enable STACKTRACE as well. 2178 2179 Say N if you are unsure. 2180 2181config TEST_REF_TRACKER 2182 tristate "Self test for reference tracker" 2183 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2184 select REF_TRACKER 2185 help 2186 This option provides a kernel module performing tests 2187 using reference tracker infrastructure. 2188 2189 Say N if you are unsure. 2190 2191config RBTREE_TEST 2192 tristate "Red-Black tree test" 2193 depends on DEBUG_KERNEL 2194 help 2195 A benchmark measuring the performance of the rbtree library. 2196 Also includes rbtree invariant checks. 2197 2198config REED_SOLOMON_TEST 2199 tristate "Reed-Solomon library test" 2200 depends on DEBUG_KERNEL || m 2201 select REED_SOLOMON 2202 select REED_SOLOMON_ENC16 2203 select REED_SOLOMON_DEC16 2204 help 2205 This option enables the self-test function of rslib at boot, 2206 or at module load time. 2207 2208 If unsure, say N. 2209 2210config INTERVAL_TREE_TEST 2211 tristate "Interval tree test" 2212 depends on DEBUG_KERNEL 2213 select INTERVAL_TREE 2214 help 2215 A benchmark measuring the performance of the interval tree library 2216 2217config PERCPU_TEST 2218 tristate "Per cpu operations test" 2219 depends on m && DEBUG_KERNEL 2220 help 2221 Enable this option to build test module which validates per-cpu 2222 operations. 2223 2224 If unsure, say N. 2225 2226config ATOMIC64_SELFTEST 2227 tristate "Perform an atomic64_t self-test" 2228 help 2229 Enable this option to test the atomic64_t functions at boot or 2230 at module load time. 2231 2232 If unsure, say N. 2233 2234config ASYNC_RAID6_TEST 2235 tristate "Self test for hardware accelerated raid6 recovery" 2236 depends on ASYNC_RAID6_RECOV 2237 select ASYNC_MEMCPY 2238 help 2239 This is a one-shot self test that permutes through the 2240 recovery of all the possible two disk failure scenarios for a 2241 N-disk array. Recovery is performed with the asynchronous 2242 raid6 recovery routines, and will optionally use an offload 2243 engine if one is available. 2244 2245 If unsure, say N. 2246 2247config TEST_HEXDUMP 2248 tristate "Test functions located in the hexdump module at runtime" 2249 2250config STRING_SELFTEST 2251 tristate "Test string functions at runtime" 2252 2253config TEST_STRING_HELPERS 2254 tristate "Test functions located in the string_helpers module at runtime" 2255 2256config TEST_STRSCPY 2257 tristate "Test strscpy*() family of functions at runtime" 2258 2259config TEST_KSTRTOX 2260 tristate "Test kstrto*() family of functions at runtime" 2261 2262config TEST_PRINTF 2263 tristate "Test printf() family of functions at runtime" 2264 2265config TEST_SCANF 2266 tristate "Test scanf() family of functions at runtime" 2267 2268config TEST_BITMAP 2269 tristate "Test bitmap_*() family of functions at runtime" 2270 help 2271 Enable this option to test the bitmap functions at boot. 2272 2273 If unsure, say N. 2274 2275config TEST_UUID 2276 tristate "Test functions located in the uuid module at runtime" 2277 2278config TEST_XARRAY 2279 tristate "Test the XArray code at runtime" 2280 2281config TEST_RHASHTABLE 2282 tristate "Perform selftest on resizable hash table" 2283 help 2284 Enable this option to test the rhashtable functions at boot. 2285 2286 If unsure, say N. 2287 2288config TEST_SIPHASH 2289 tristate "Perform selftest on siphash functions" 2290 help 2291 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2292 functions on boot (or module load). 2293 2294 This is intended to help people writing architecture-specific 2295 optimized versions. If unsure, say N. 2296 2297config TEST_IDA 2298 tristate "Perform selftest on IDA functions" 2299 2300config TEST_PARMAN 2301 tristate "Perform selftest on priority array manager" 2302 depends on PARMAN 2303 help 2304 Enable this option to test priority array manager on boot 2305 (or module load). 2306 2307 If unsure, say N. 2308 2309config TEST_IRQ_TIMINGS 2310 bool "IRQ timings selftest" 2311 depends on IRQ_TIMINGS 2312 help 2313 Enable this option to test the irq timings code on boot. 2314 2315 If unsure, say N. 2316 2317config TEST_LKM 2318 tristate "Test module loading with 'hello world' module" 2319 depends on m 2320 help 2321 This builds the "test_module" module that emits "Hello, world" 2322 on printk when loaded. It is designed to be used for basic 2323 evaluation of the module loading subsystem (for example when 2324 validating module verification). It lacks any extra dependencies, 2325 and will not normally be loaded by the system unless explicitly 2326 requested by name. 2327 2328 If unsure, say N. 2329 2330config TEST_BITOPS 2331 tristate "Test module for compilation of bitops operations" 2332 depends on m 2333 help 2334 This builds the "test_bitops" module that is much like the 2335 TEST_LKM module except that it does a basic exercise of the 2336 set/clear_bit macros and get_count_order/long to make sure there are 2337 no compiler warnings from C=1 sparse checker or -Wextra 2338 compilations. It has no dependencies and doesn't run or load unless 2339 explicitly requested by name. for example: modprobe test_bitops. 2340 2341 If unsure, say N. 2342 2343config TEST_VMALLOC 2344 tristate "Test module for stress/performance analysis of vmalloc allocator" 2345 default n 2346 depends on MMU 2347 depends on m 2348 help 2349 This builds the "test_vmalloc" module that should be used for 2350 stress and performance analysis. So, any new change for vmalloc 2351 subsystem can be evaluated from performance and stability point 2352 of view. 2353 2354 If unsure, say N. 2355 2356config TEST_USER_COPY 2357 tristate "Test user/kernel boundary protections" 2358 depends on m 2359 help 2360 This builds the "test_user_copy" module that runs sanity checks 2361 on the copy_to/from_user infrastructure, making sure basic 2362 user/kernel boundary testing is working. If it fails to load, 2363 a regression has been detected in the user/kernel memory boundary 2364 protections. 2365 2366 If unsure, say N. 2367 2368config TEST_BPF 2369 tristate "Test BPF filter functionality" 2370 depends on m && NET 2371 help 2372 This builds the "test_bpf" module that runs various test vectors 2373 against the BPF interpreter or BPF JIT compiler depending on the 2374 current setting. This is in particular useful for BPF JIT compiler 2375 development, but also to run regression tests against changes in 2376 the interpreter code. It also enables test stubs for eBPF maps and 2377 verifier used by user space verifier testsuite. 2378 2379 If unsure, say N. 2380 2381config TEST_BLACKHOLE_DEV 2382 tristate "Test blackhole netdev functionality" 2383 depends on m && NET 2384 help 2385 This builds the "test_blackhole_dev" module that validates the 2386 data path through this blackhole netdev. 2387 2388 If unsure, say N. 2389 2390config FIND_BIT_BENCHMARK 2391 tristate "Test find_bit functions" 2392 help 2393 This builds the "test_find_bit" module that measure find_*_bit() 2394 functions performance. 2395 2396 If unsure, say N. 2397 2398config TEST_FIRMWARE 2399 tristate "Test firmware loading via userspace interface" 2400 depends on FW_LOADER 2401 help 2402 This builds the "test_firmware" module that creates a userspace 2403 interface for testing firmware loading. This can be used to 2404 control the triggering of firmware loading without needing an 2405 actual firmware-using device. The contents can be rechecked by 2406 userspace. 2407 2408 If unsure, say N. 2409 2410config TEST_SYSCTL 2411 tristate "sysctl test driver" 2412 depends on PROC_SYSCTL 2413 help 2414 This builds the "test_sysctl" module. This driver enables to test the 2415 proc sysctl interfaces available to drivers safely without affecting 2416 production knobs which might alter system functionality. 2417 2418 If unsure, say N. 2419 2420config BITFIELD_KUNIT 2421 tristate "KUnit test bitfield functions at runtime" 2422 depends on KUNIT 2423 help 2424 Enable this option to test the bitfield functions at boot. 2425 2426 KUnit tests run during boot and output the results to the debug log 2427 in TAP format (http://testanything.org/). Only useful for kernel devs 2428 running the KUnit test harness, and not intended for inclusion into a 2429 production build. 2430 2431 For more information on KUnit and unit tests in general please refer 2432 to the KUnit documentation in Documentation/dev-tools/kunit/. 2433 2434 If unsure, say N. 2435 2436config HASH_KUNIT_TEST 2437 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2438 depends on KUNIT 2439 default KUNIT_ALL_TESTS 2440 help 2441 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2442 integer (<linux/hash.h>) hash functions on boot. 2443 2444 KUnit tests run during boot and output the results to the debug log 2445 in TAP format (https://testanything.org/). Only useful for kernel devs 2446 running the KUnit test harness, and not intended for inclusion into a 2447 production build. 2448 2449 For more information on KUnit and unit tests in general please refer 2450 to the KUnit documentation in Documentation/dev-tools/kunit/. 2451 2452 This is intended to help people writing architecture-specific 2453 optimized versions. If unsure, say N. 2454 2455config RESOURCE_KUNIT_TEST 2456 tristate "KUnit test for resource API" 2457 depends on KUNIT 2458 help 2459 This builds the resource API unit test. 2460 Tests the logic of API provided by resource.c and ioport.h. 2461 For more information on KUnit and unit tests in general please refer 2462 to the KUnit documentation in Documentation/dev-tools/kunit/. 2463 2464 If unsure, say N. 2465 2466config SYSCTL_KUNIT_TEST 2467 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2468 depends on KUNIT 2469 default KUNIT_ALL_TESTS 2470 help 2471 This builds the proc sysctl unit test, which runs on boot. 2472 Tests the API contract and implementation correctness of sysctl. 2473 For more information on KUnit and unit tests in general please refer 2474 to the KUnit documentation in Documentation/dev-tools/kunit/. 2475 2476 If unsure, say N. 2477 2478config LIST_KUNIT_TEST 2479 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2480 depends on KUNIT 2481 default KUNIT_ALL_TESTS 2482 help 2483 This builds the linked list KUnit test suite. 2484 It tests that the API and basic functionality of the list_head type 2485 and associated macros. 2486 2487 KUnit tests run during boot and output the results to the debug log 2488 in TAP format (https://testanything.org/). Only useful for kernel devs 2489 running the KUnit test harness, and not intended for inclusion into a 2490 production build. 2491 2492 For more information on KUnit and unit tests in general please refer 2493 to the KUnit documentation in Documentation/dev-tools/kunit/. 2494 2495 If unsure, say N. 2496 2497config LINEAR_RANGES_TEST 2498 tristate "KUnit test for linear_ranges" 2499 depends on KUNIT 2500 select LINEAR_RANGES 2501 help 2502 This builds the linear_ranges unit test, which runs on boot. 2503 Tests the linear_ranges logic correctness. 2504 For more information on KUnit and unit tests in general please refer 2505 to the KUnit documentation in Documentation/dev-tools/kunit/. 2506 2507 If unsure, say N. 2508 2509config CMDLINE_KUNIT_TEST 2510 tristate "KUnit test for cmdline API" 2511 depends on KUNIT 2512 help 2513 This builds the cmdline API unit test. 2514 Tests the logic of API provided by cmdline.c. 2515 For more information on KUnit and unit tests in general please refer 2516 to the KUnit documentation in Documentation/dev-tools/kunit/. 2517 2518 If unsure, say N. 2519 2520config BITS_TEST 2521 tristate "KUnit test for bits.h" 2522 depends on KUNIT 2523 help 2524 This builds the bits unit test. 2525 Tests the logic of macros defined in bits.h. 2526 For more information on KUnit and unit tests in general please refer 2527 to the KUnit documentation in Documentation/dev-tools/kunit/. 2528 2529 If unsure, say N. 2530 2531config SLUB_KUNIT_TEST 2532 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2533 depends on SLUB_DEBUG && KUNIT 2534 default KUNIT_ALL_TESTS 2535 help 2536 This builds SLUB allocator unit test. 2537 Tests SLUB cache debugging functionality. 2538 For more information on KUnit and unit tests in general please refer 2539 to the KUnit documentation in Documentation/dev-tools/kunit/. 2540 2541 If unsure, say N. 2542 2543config RATIONAL_KUNIT_TEST 2544 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2545 depends on KUNIT && RATIONAL 2546 default KUNIT_ALL_TESTS 2547 help 2548 This builds the rational math unit test. 2549 For more information on KUnit and unit tests in general please refer 2550 to the KUnit documentation in Documentation/dev-tools/kunit/. 2551 2552 If unsure, say N. 2553 2554config MEMCPY_KUNIT_TEST 2555 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2556 depends on KUNIT 2557 default KUNIT_ALL_TESTS 2558 help 2559 Builds unit tests for memcpy(), memmove(), and memset() functions. 2560 For more information on KUnit and unit tests in general please refer 2561 to the KUnit documentation in Documentation/dev-tools/kunit/. 2562 2563 If unsure, say N. 2564 2565config OVERFLOW_KUNIT_TEST 2566 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2567 depends on KUNIT 2568 default KUNIT_ALL_TESTS 2569 help 2570 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2571 related functions. 2572 2573 For more information on KUnit and unit tests in general please refer 2574 to the KUnit documentation in Documentation/dev-tools/kunit/. 2575 2576 If unsure, say N. 2577 2578config STACKINIT_KUNIT_TEST 2579 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2580 depends on KUNIT 2581 default KUNIT_ALL_TESTS 2582 help 2583 Test if the kernel is zero-initializing stack variables and 2584 padding. Coverage is controlled by compiler flags, 2585 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2586 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2587 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2588 2589config TEST_UDELAY 2590 tristate "udelay test driver" 2591 help 2592 This builds the "udelay_test" module that helps to make sure 2593 that udelay() is working properly. 2594 2595 If unsure, say N. 2596 2597config TEST_STATIC_KEYS 2598 tristate "Test static keys" 2599 depends on m 2600 help 2601 Test the static key interfaces. 2602 2603 If unsure, say N. 2604 2605config TEST_KMOD 2606 tristate "kmod stress tester" 2607 depends on m 2608 depends on NETDEVICES && NET_CORE && INET # for TUN 2609 depends on BLOCK 2610 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2611 select TEST_LKM 2612 select XFS_FS 2613 select TUN 2614 select BTRFS_FS 2615 help 2616 Test the kernel's module loading mechanism: kmod. kmod implements 2617 support to load modules using the Linux kernel's usermode helper. 2618 This test provides a series of tests against kmod. 2619 2620 Although technically you can either build test_kmod as a module or 2621 into the kernel we disallow building it into the kernel since 2622 it stress tests request_module() and this will very likely cause 2623 some issues by taking over precious threads available from other 2624 module load requests, ultimately this could be fatal. 2625 2626 To run tests run: 2627 2628 tools/testing/selftests/kmod/kmod.sh --help 2629 2630 If unsure, say N. 2631 2632config TEST_DEBUG_VIRTUAL 2633 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2634 depends on DEBUG_VIRTUAL 2635 help 2636 Test the kernel's ability to detect incorrect calls to 2637 virt_to_phys() done against the non-linear part of the 2638 kernel's virtual address map. 2639 2640 If unsure, say N. 2641 2642config TEST_MEMCAT_P 2643 tristate "Test memcat_p() helper function" 2644 help 2645 Test the memcat_p() helper for correctly merging two 2646 pointer arrays together. 2647 2648 If unsure, say N. 2649 2650config TEST_LIVEPATCH 2651 tristate "Test livepatching" 2652 default n 2653 depends on DYNAMIC_DEBUG 2654 depends on LIVEPATCH 2655 depends on m 2656 help 2657 Test kernel livepatching features for correctness. The tests will 2658 load test modules that will be livepatched in various scenarios. 2659 2660 To run all the livepatching tests: 2661 2662 make -C tools/testing/selftests TARGETS=livepatch run_tests 2663 2664 Alternatively, individual tests may be invoked: 2665 2666 tools/testing/selftests/livepatch/test-callbacks.sh 2667 tools/testing/selftests/livepatch/test-livepatch.sh 2668 tools/testing/selftests/livepatch/test-shadow-vars.sh 2669 2670 If unsure, say N. 2671 2672config TEST_OBJAGG 2673 tristate "Perform selftest on object aggreration manager" 2674 default n 2675 depends on OBJAGG 2676 help 2677 Enable this option to test object aggregation manager on boot 2678 (or module load). 2679 2680config TEST_MEMINIT 2681 tristate "Test heap/page initialization" 2682 help 2683 Test if the kernel is zero-initializing heap and page allocations. 2684 This can be useful to test init_on_alloc and init_on_free features. 2685 2686 If unsure, say N. 2687 2688config TEST_HMM 2689 tristate "Test HMM (Heterogeneous Memory Management)" 2690 depends on TRANSPARENT_HUGEPAGE 2691 depends on DEVICE_PRIVATE 2692 select HMM_MIRROR 2693 select MMU_NOTIFIER 2694 help 2695 This is a pseudo device driver solely for testing HMM. 2696 Say M here if you want to build the HMM test module. 2697 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2698 2699 If unsure, say N. 2700 2701config TEST_FREE_PAGES 2702 tristate "Test freeing pages" 2703 help 2704 Test that a memory leak does not occur due to a race between 2705 freeing a block of pages and a speculative page reference. 2706 Loading this module is safe if your kernel has the bug fixed. 2707 If the bug is not fixed, it will leak gigabytes of memory and 2708 probably OOM your system. 2709 2710config TEST_FPU 2711 tristate "Test floating point operations in kernel space" 2712 depends on X86 && !KCOV_INSTRUMENT_ALL 2713 help 2714 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2715 which will trigger a sequence of floating point operations. This is used 2716 for self-testing floating point control register setting in 2717 kernel_fpu_begin(). 2718 2719 If unsure, say N. 2720 2721config TEST_CLOCKSOURCE_WATCHDOG 2722 tristate "Test clocksource watchdog in kernel space" 2723 depends on CLOCKSOURCE_WATCHDOG 2724 help 2725 Enable this option to create a kernel module that will trigger 2726 a test of the clocksource watchdog. This module may be loaded 2727 via modprobe or insmod in which case it will run upon being 2728 loaded, or it may be built in, in which case it will run 2729 shortly after boot. 2730 2731 If unsure, say N. 2732 2733endif # RUNTIME_TESTING_MENU 2734 2735config ARCH_USE_MEMTEST 2736 bool 2737 help 2738 An architecture should select this when it uses early_memtest() 2739 during boot process. 2740 2741config MEMTEST 2742 bool "Memtest" 2743 depends on ARCH_USE_MEMTEST 2744 help 2745 This option adds a kernel parameter 'memtest', which allows memtest 2746 to be set and executed. 2747 memtest=0, mean disabled; -- default 2748 memtest=1, mean do 1 test pattern; 2749 ... 2750 memtest=17, mean do 17 test patterns. 2751 If you are unsure how to answer this question, answer N. 2752 2753 2754 2755config HYPERV_TESTING 2756 bool "Microsoft Hyper-V driver testing" 2757 default n 2758 depends on HYPERV && DEBUG_FS 2759 help 2760 Select this option to enable Hyper-V vmbus testing. 2761 2762endmenu # "Kernel Testing and Coverage" 2763 2764source "Documentation/Kconfig" 2765 2766endmenu # Kernel hacking 2767