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