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" 210 211# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which 212# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 213config AS_HAS_NON_CONST_LEB128 214 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) 215 216menu "Compile-time checks and compiler options" 217 218config DEBUG_INFO 219 bool "Compile the kernel with debug info" 220 depends on DEBUG_KERNEL && !COMPILE_TEST 221 help 222 If you say Y here the resulting kernel image will include 223 debugging info resulting in a larger kernel image. 224 This adds debug symbols to the kernel and modules (gcc -g), and 225 is needed if you intend to use kernel crashdump or binary object 226 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 227 Say Y here only if you plan to debug the kernel. 228 229 If unsure, say N. 230 231if DEBUG_INFO 232 233config DEBUG_INFO_REDUCED 234 bool "Reduce debugging information" 235 help 236 If you say Y here gcc is instructed to generate less debugging 237 information for structure types. This means that tools that 238 need full debugging information (like kgdb or systemtap) won't 239 be happy. But if you merely need debugging information to 240 resolve line numbers there is no loss. Advantage is that 241 build directory object sizes shrink dramatically over a full 242 DEBUG_INFO build and compile times are reduced too. 243 Only works with newer gcc versions. 244 245config DEBUG_INFO_COMPRESSED 246 bool "Compressed debugging information" 247 depends on $(cc-option,-gz=zlib) 248 depends on $(ld-option,--compress-debug-sections=zlib) 249 help 250 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 251 5.0+, binutils 2.26+, and zlib. 252 253 Users of dpkg-deb via scripts/package/builddeb may find an increase in 254 size of their debug .deb packages with this config set, due to the 255 debug info being compressed with zlib, then the object files being 256 recompressed with a different compression scheme. But this is still 257 preferable to setting $KDEB_COMPRESS to "none" which would be even 258 larger. 259 260config DEBUG_INFO_SPLIT 261 bool "Produce split debuginfo in .dwo files" 262 depends on $(cc-option,-gsplit-dwarf) 263 help 264 Generate debug info into separate .dwo files. This significantly 265 reduces the build directory size for builds with DEBUG_INFO, 266 because it stores the information only once on disk in .dwo 267 files instead of multiple times in object files and executables. 268 In addition the debug information is also compressed. 269 270 Requires recent gcc (4.7+) and recent gdb/binutils. 271 Any tool that packages or reads debug information would need 272 to know about the .dwo files and include them. 273 Incompatible with older versions of ccache. 274 275choice 276 prompt "DWARF version" 277 help 278 Which version of DWARF debug info to emit. 279 280config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 281 bool "Rely on the toolchain's implicit default DWARF version" 282 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) 283 help 284 The implicit default version of DWARF debug info produced by a 285 toolchain changes over time. 286 287 This can break consumers of the debug info that haven't upgraded to 288 support newer revisions, and prevent testing newer versions, but 289 those should be less common scenarios. 290 291 If unsure, say Y. 292 293config DEBUG_INFO_DWARF4 294 bool "Generate DWARF Version 4 debuginfo" 295 help 296 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. 297 298 If you have consumers of DWARF debug info that are not ready for 299 newer revisions of DWARF, you may wish to choose this or have your 300 config select this. 301 302config DEBUG_INFO_DWARF5 303 bool "Generate DWARF Version 5 debuginfo" 304 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) 305 depends on !DEBUG_INFO_BTF || PAHOLE_VERSION >= 121 306 help 307 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 308 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 309 draft features until 7.0), and gdb 8.0+. 310 311 Changes to the structure of debug info in Version 5 allow for around 312 15-18% savings in resulting image and debug info section sizes as 313 compared to DWARF Version 4. DWARF Version 5 standardizes previous 314 extensions such as accelerators for symbol indexing and the format 315 for fission (.dwo/.dwp) files. Users may not want to select this 316 config if they rely on tooling that has not yet been updated to 317 support DWARF Version 5. 318 319endchoice # "DWARF version" 320 321config DEBUG_INFO_BTF 322 bool "Generate BTF typeinfo" 323 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 324 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 325 help 326 Generate deduplicated BTF type information from DWARF debug info. 327 Turning this on expects presence of pahole tool, which will convert 328 DWARF type info into equivalent deduplicated BTF type info. 329 330config PAHOLE_HAS_SPLIT_BTF 331 def_bool PAHOLE_VERSION >= 119 332 333config DEBUG_INFO_BTF_MODULES 334 def_bool y 335 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 336 help 337 Generate compact split BTF type information for kernel modules. 338 339config MODULE_ALLOW_BTF_MISMATCH 340 bool "Allow loading modules with non-matching BTF type info" 341 depends on DEBUG_INFO_BTF_MODULES 342 help 343 For modules whose split BTF does not match vmlinux, load without 344 BTF rather than refusing to load. The default behavior with 345 module BTF enabled is to reject modules with such mismatches; 346 this option will still load module BTF where possible but ignore 347 it when a mismatch is found. 348 349config GDB_SCRIPTS 350 bool "Provide GDB scripts for kernel debugging" 351 help 352 This creates the required links to GDB helper scripts in the 353 build directory. If you load vmlinux into gdb, the helper 354 scripts will be automatically imported by gdb as well, and 355 additional functions are available to analyze a Linux kernel 356 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 357 for further details. 358 359endif # DEBUG_INFO 360 361config FRAME_WARN 362 int "Warn for stack frames larger than" 363 range 0 8192 364 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 365 default 2048 if PARISC 366 default 1536 if (!64BIT && XTENSA) 367 default 1280 if KASAN && !64BIT 368 default 1024 if !64BIT 369 default 2048 if 64BIT 370 help 371 Tell gcc to warn at build time for stack frames larger than this. 372 Setting this too low will cause a lot of warnings. 373 Setting it to 0 disables the warning. 374 375config STRIP_ASM_SYMS 376 bool "Strip assembler-generated symbols during link" 377 default n 378 help 379 Strip internal assembler-generated symbols during a link (symbols 380 that look like '.Lxxx') so they don't pollute the output of 381 get_wchan() and suchlike. 382 383config READABLE_ASM 384 bool "Generate readable assembler code" 385 depends on DEBUG_KERNEL 386 depends on CC_IS_GCC 387 help 388 Disable some compiler optimizations that tend to generate human unreadable 389 assembler output. This may make the kernel slightly slower, but it helps 390 to keep kernel developers who have to stare a lot at assembler listings 391 sane. 392 393config HEADERS_INSTALL 394 bool "Install uapi headers to usr/include" 395 depends on !UML 396 help 397 This option will install uapi headers (headers exported to user-space) 398 into the usr/include directory for use during the kernel build. 399 This is unneeded for building the kernel itself, but needed for some 400 user-space program samples. It is also needed by some features such 401 as uapi header sanity checks. 402 403config DEBUG_SECTION_MISMATCH 404 bool "Enable full Section mismatch analysis" 405 depends on CC_IS_GCC 406 help 407 The section mismatch analysis checks if there are illegal 408 references from one section to another section. 409 During linktime or runtime, some sections are dropped; 410 any use of code/data previously in these sections would 411 most likely result in an oops. 412 In the code, functions and variables are annotated with 413 __init,, etc. (see the full list in include/linux/init.h), 414 which results in the code/data being placed in specific sections. 415 The section mismatch analysis is always performed after a full 416 kernel build, and enabling this option causes the following 417 additional step to occur: 418 - Add the option -fno-inline-functions-called-once to gcc commands. 419 When inlining a function annotated with __init in a non-init 420 function, we would lose the section information and thus 421 the analysis would not catch the illegal reference. 422 This option tells gcc to inline less (but it does result in 423 a larger kernel). 424 425config SECTION_MISMATCH_WARN_ONLY 426 bool "Make section mismatch errors non-fatal" 427 default y 428 help 429 If you say N here, the build process will fail if there are any 430 section mismatch, instead of just throwing warnings. 431 432 If unsure, say Y. 433 434config DEBUG_FORCE_FUNCTION_ALIGN_64B 435 bool "Force all function address 64B aligned" 436 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 437 help 438 There are cases that a commit from one domain changes the function 439 address alignment of other domains, and cause magic performance 440 bump (regression or improvement). Enable this option will help to 441 verify if the bump is caused by function alignment changes, while 442 it will slightly increase the kernel size and affect icache usage. 443 444 It is mainly for debug and performance tuning use. 445 446# 447# Select this config option from the architecture Kconfig, if it 448# is preferred to always offer frame pointers as a config 449# option on the architecture (regardless of KERNEL_DEBUG): 450# 451config ARCH_WANT_FRAME_POINTERS 452 bool 453 454config FRAME_POINTER 455 bool "Compile the kernel with frame pointers" 456 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 457 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 458 help 459 If you say Y here the resulting kernel image will be slightly 460 larger and slower, but it gives very useful debugging information 461 in case of kernel bugs. (precise oopses/stacktraces/warnings) 462 463config STACK_VALIDATION 464 bool "Compile-time stack metadata validation" 465 depends on HAVE_STACK_VALIDATION 466 default n 467 help 468 Add compile-time checks to validate stack metadata, including frame 469 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure 470 that runtime stack traces are more reliable. 471 472 This is also a prerequisite for generation of ORC unwind data, which 473 is needed for CONFIG_UNWINDER_ORC. 474 475 For more information, see 476 tools/objtool/Documentation/stack-validation.txt. 477 478config VMLINUX_VALIDATION 479 bool 480 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT 481 default y 482 483config VMLINUX_MAP 484 bool "Generate vmlinux.map file when linking" 485 depends on EXPERT 486 help 487 Selecting this option will pass "-Map=vmlinux.map" to ld 488 when linking vmlinux. That file can be useful for verifying 489 and debugging magic section games, and for seeing which 490 pieces of code get eliminated with 491 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 492 493config DEBUG_FORCE_WEAK_PER_CPU 494 bool "Force weak per-cpu definitions" 495 depends on DEBUG_KERNEL 496 help 497 s390 and alpha require percpu variables in modules to be 498 defined weak to work around addressing range issue which 499 puts the following two restrictions on percpu variable 500 definitions. 501 502 1. percpu symbols must be unique whether static or not 503 2. percpu variables can't be defined inside a function 504 505 To ensure that generic code follows the above rules, this 506 option forces all percpu variables to be defined as weak. 507 508endmenu # "Compiler options" 509 510menu "Generic Kernel Debugging Instruments" 511 512config MAGIC_SYSRQ 513 bool "Magic SysRq key" 514 depends on !UML 515 help 516 If you say Y here, you will have some control over the system even 517 if the system crashes for example during kernel debugging (e.g., you 518 will be able to flush the buffer cache to disk, reboot the system 519 immediately or dump some status information). This is accomplished 520 by pressing various keys while holding SysRq (Alt+PrintScreen). It 521 also works on a serial console (on PC hardware at least), if you 522 send a BREAK and then within 5 seconds a command keypress. The 523 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 524 Don't say Y unless you really know what this hack does. 525 526config MAGIC_SYSRQ_DEFAULT_ENABLE 527 hex "Enable magic SysRq key functions by default" 528 depends on MAGIC_SYSRQ 529 default 0x1 530 help 531 Specifies which SysRq key functions are enabled by default. 532 This may be set to 1 or 0 to enable or disable them all, or 533 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 534 535config MAGIC_SYSRQ_SERIAL 536 bool "Enable magic SysRq key over serial" 537 depends on MAGIC_SYSRQ 538 default y 539 help 540 Many embedded boards have a disconnected TTL level serial which can 541 generate some garbage that can lead to spurious false sysrq detects. 542 This option allows you to decide whether you want to enable the 543 magic SysRq key. 544 545config MAGIC_SYSRQ_SERIAL_SEQUENCE 546 string "Char sequence that enables magic SysRq over serial" 547 depends on MAGIC_SYSRQ_SERIAL 548 default "" 549 help 550 Specifies a sequence of characters that can follow BREAK to enable 551 SysRq on a serial console. 552 553 If unsure, leave an empty string and the option will not be enabled. 554 555config DEBUG_FS 556 bool "Debug Filesystem" 557 help 558 debugfs is a virtual file system that kernel developers use to put 559 debugging files into. Enable this option to be able to read and 560 write to these files. 561 562 For detailed documentation on the debugfs API, see 563 Documentation/filesystems/. 564 565 If unsure, say N. 566 567choice 568 prompt "Debugfs default access" 569 depends on DEBUG_FS 570 default DEBUG_FS_ALLOW_ALL 571 help 572 This selects the default access restrictions for debugfs. 573 It can be overridden with kernel command line option 574 debugfs=[on,no-mount,off]. The restrictions apply for API access 575 and filesystem registration. 576 577config DEBUG_FS_ALLOW_ALL 578 bool "Access normal" 579 help 580 No restrictions apply. Both API and filesystem registration 581 is on. This is the normal default operation. 582 583config DEBUG_FS_DISALLOW_MOUNT 584 bool "Do not register debugfs as filesystem" 585 help 586 The API is open but filesystem is not loaded. Clients can still do 587 their work and read with debug tools that do not need 588 debugfs filesystem. 589 590config DEBUG_FS_ALLOW_NONE 591 bool "No access" 592 help 593 Access is off. Clients get -PERM when trying to create nodes in 594 debugfs tree and debugfs is not registered as a filesystem. 595 Client can then back-off or continue without debugfs access. 596 597endchoice 598 599source "lib/Kconfig.kgdb" 600source "lib/Kconfig.ubsan" 601source "lib/Kconfig.kcsan" 602 603endmenu 604 605config DEBUG_KERNEL 606 bool "Kernel debugging" 607 help 608 Say Y here if you are developing drivers or trying to debug and 609 identify kernel problems. 610 611config DEBUG_MISC 612 bool "Miscellaneous debug code" 613 default DEBUG_KERNEL 614 depends on DEBUG_KERNEL 615 help 616 Say Y here if you need to enable miscellaneous debug code that should 617 be under a more specific debug option but isn't. 618 619 620menu "Memory Debugging" 621 622source "mm/Kconfig.debug" 623 624config DEBUG_OBJECTS 625 bool "Debug object operations" 626 depends on DEBUG_KERNEL 627 help 628 If you say Y here, additional code will be inserted into the 629 kernel to track the life time of various objects and validate 630 the operations on those objects. 631 632config DEBUG_OBJECTS_SELFTEST 633 bool "Debug objects selftest" 634 depends on DEBUG_OBJECTS 635 help 636 This enables the selftest of the object debug code. 637 638config DEBUG_OBJECTS_FREE 639 bool "Debug objects in freed memory" 640 depends on DEBUG_OBJECTS 641 help 642 This enables checks whether a k/v free operation frees an area 643 which contains an object which has not been deactivated 644 properly. This can make kmalloc/kfree-intensive workloads 645 much slower. 646 647config DEBUG_OBJECTS_TIMERS 648 bool "Debug timer objects" 649 depends on DEBUG_OBJECTS 650 help 651 If you say Y here, additional code will be inserted into the 652 timer routines to track the life time of timer objects and 653 validate the timer operations. 654 655config DEBUG_OBJECTS_WORK 656 bool "Debug work objects" 657 depends on DEBUG_OBJECTS 658 help 659 If you say Y here, additional code will be inserted into the 660 work queue routines to track the life time of work objects and 661 validate the work operations. 662 663config DEBUG_OBJECTS_RCU_HEAD 664 bool "Debug RCU callbacks objects" 665 depends on DEBUG_OBJECTS 666 help 667 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 668 669config DEBUG_OBJECTS_PERCPU_COUNTER 670 bool "Debug percpu counter objects" 671 depends on DEBUG_OBJECTS 672 help 673 If you say Y here, additional code will be inserted into the 674 percpu counter routines to track the life time of percpu counter 675 objects and validate the percpu counter operations. 676 677config DEBUG_OBJECTS_ENABLE_DEFAULT 678 int "debug_objects bootup default value (0-1)" 679 range 0 1 680 default "1" 681 depends on DEBUG_OBJECTS 682 help 683 Debug objects boot parameter default value 684 685config DEBUG_SLAB 686 bool "Debug slab memory allocations" 687 depends on DEBUG_KERNEL && SLAB 688 help 689 Say Y here to have the kernel do limited verification on memory 690 allocation as well as poisoning memory on free to catch use of freed 691 memory. This can make kmalloc/kfree-intensive workloads much slower. 692 693config SLUB_DEBUG_ON 694 bool "SLUB debugging on by default" 695 depends on SLUB && SLUB_DEBUG 696 default n 697 help 698 Boot with debugging on by default. SLUB boots by default with 699 the runtime debug capabilities switched off. Enabling this is 700 equivalent to specifying the "slub_debug" parameter on boot. 701 There is no support for more fine grained debug control like 702 possible with slub_debug=xxx. SLUB debugging may be switched 703 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 704 "slub_debug=-". 705 706config SLUB_STATS 707 default n 708 bool "Enable SLUB performance statistics" 709 depends on SLUB && SYSFS 710 help 711 SLUB statistics are useful to debug SLUBs allocation behavior in 712 order find ways to optimize the allocator. This should never be 713 enabled for production use since keeping statistics slows down 714 the allocator by a few percentage points. The slabinfo command 715 supports the determination of the most active slabs to figure 716 out which slabs are relevant to a particular load. 717 Try running: slabinfo -DA 718 719config HAVE_DEBUG_KMEMLEAK 720 bool 721 722config DEBUG_KMEMLEAK 723 bool "Kernel memory leak detector" 724 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 725 select DEBUG_FS 726 select STACKTRACE if STACKTRACE_SUPPORT 727 select KALLSYMS 728 select CRC32 729 help 730 Say Y here if you want to enable the memory leak 731 detector. The memory allocation/freeing is traced in a way 732 similar to the Boehm's conservative garbage collector, the 733 difference being that the orphan objects are not freed but 734 only shown in /sys/kernel/debug/kmemleak. Enabling this 735 feature will introduce an overhead to memory 736 allocations. See Documentation/dev-tools/kmemleak.rst for more 737 details. 738 739 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 740 of finding leaks due to the slab objects poisoning. 741 742 In order to access the kmemleak file, debugfs needs to be 743 mounted (usually at /sys/kernel/debug). 744 745config DEBUG_KMEMLEAK_MEM_POOL_SIZE 746 int "Kmemleak memory pool size" 747 depends on DEBUG_KMEMLEAK 748 range 200 1000000 749 default 16000 750 help 751 Kmemleak must track all the memory allocations to avoid 752 reporting false positives. Since memory may be allocated or 753 freed before kmemleak is fully initialised, use a static pool 754 of metadata objects to track such callbacks. After kmemleak is 755 fully initialised, this memory pool acts as an emergency one 756 if slab allocations fail. 757 758config DEBUG_KMEMLEAK_TEST 759 tristate "Simple test for the kernel memory leak detector" 760 depends on DEBUG_KMEMLEAK && m 761 help 762 This option enables a module that explicitly leaks memory. 763 764 If unsure, say N. 765 766config DEBUG_KMEMLEAK_DEFAULT_OFF 767 bool "Default kmemleak to off" 768 depends on DEBUG_KMEMLEAK 769 help 770 Say Y here to disable kmemleak by default. It can then be enabled 771 on the command line via kmemleak=on. 772 773config DEBUG_KMEMLEAK_AUTO_SCAN 774 bool "Enable kmemleak auto scan thread on boot up" 775 default y 776 depends on DEBUG_KMEMLEAK 777 help 778 Depending on the cpu, kmemleak scan may be cpu intensive and can 779 stall user tasks at times. This option enables/disables automatic 780 kmemleak scan at boot up. 781 782 Say N here to disable kmemleak auto scan thread to stop automatic 783 scanning. Disabling this option disables automatic reporting of 784 memory leaks. 785 786 If unsure, say Y. 787 788config DEBUG_STACK_USAGE 789 bool "Stack utilization instrumentation" 790 depends on DEBUG_KERNEL && !IA64 791 help 792 Enables the display of the minimum amount of free stack which each 793 task has ever had available in the sysrq-T and sysrq-P debug output. 794 795 This option will slow down process creation somewhat. 796 797config SCHED_STACK_END_CHECK 798 bool "Detect stack corruption on calls to schedule()" 799 depends on DEBUG_KERNEL 800 default n 801 help 802 This option checks for a stack overrun on calls to schedule(). 803 If the stack end location is found to be over written always panic as 804 the content of the corrupted region can no longer be trusted. 805 This is to ensure no erroneous behaviour occurs which could result in 806 data corruption or a sporadic crash at a later stage once the region 807 is examined. The runtime overhead introduced is minimal. 808 809config ARCH_HAS_DEBUG_VM_PGTABLE 810 bool 811 help 812 An architecture should select this when it can successfully 813 build and run DEBUG_VM_PGTABLE. 814 815config DEBUG_VM 816 bool "Debug VM" 817 depends on DEBUG_KERNEL 818 help 819 Enable this to turn on extended checks in the virtual-memory system 820 that may impact performance. 821 822 If unsure, say N. 823 824config DEBUG_VM_VMACACHE 825 bool "Debug VMA caching" 826 depends on DEBUG_VM 827 help 828 Enable this to turn on VMA caching debug information. Doing so 829 can cause significant overhead, so only enable it in non-production 830 environments. 831 832 If unsure, say N. 833 834config DEBUG_VM_RB 835 bool "Debug VM red-black trees" 836 depends on DEBUG_VM 837 help 838 Enable VM red-black tree debugging information and extra validations. 839 840 If unsure, say N. 841 842config DEBUG_VM_PGFLAGS 843 bool "Debug page-flags operations" 844 depends on DEBUG_VM 845 help 846 Enables extra validation on page flags operations. 847 848 If unsure, say N. 849 850config DEBUG_VM_PGTABLE 851 bool "Debug arch page table for semantics compliance" 852 depends on MMU 853 depends on ARCH_HAS_DEBUG_VM_PGTABLE 854 default y if DEBUG_VM 855 help 856 This option provides a debug method which can be used to test 857 architecture page table helper functions on various platforms in 858 verifying if they comply with expected generic MM semantics. This 859 will help architecture code in making sure that any changes or 860 new additions of these helpers still conform to expected 861 semantics of the generic MM. Platforms will have to opt in for 862 this through ARCH_HAS_DEBUG_VM_PGTABLE. 863 864 If unsure, say N. 865 866config ARCH_HAS_DEBUG_VIRTUAL 867 bool 868 869config DEBUG_VIRTUAL 870 bool "Debug VM translations" 871 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 872 help 873 Enable some costly sanity checks in virtual to page code. This can 874 catch mistakes with virt_to_page() and friends. 875 876 If unsure, say N. 877 878config DEBUG_NOMMU_REGIONS 879 bool "Debug the global anon/private NOMMU mapping region tree" 880 depends on DEBUG_KERNEL && !MMU 881 help 882 This option causes the global tree of anonymous and private mapping 883 regions to be regularly checked for invalid topology. 884 885config DEBUG_MEMORY_INIT 886 bool "Debug memory initialisation" if EXPERT 887 default !EXPERT 888 help 889 Enable this for additional checks during memory initialisation. 890 The sanity checks verify aspects of the VM such as the memory model 891 and other information provided by the architecture. Verbose 892 information will be printed at KERN_DEBUG loglevel depending 893 on the mminit_loglevel= command-line option. 894 895 If unsure, say Y 896 897config MEMORY_NOTIFIER_ERROR_INJECT 898 tristate "Memory hotplug notifier error injection module" 899 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION 900 help 901 This option provides the ability to inject artificial errors to 902 memory hotplug notifier chain callbacks. It is controlled through 903 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 904 905 If the notifier call chain should be failed with some events 906 notified, write the error code to "actions/<notifier event>/error". 907 908 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 909 910 # cd /sys/kernel/debug/notifier-error-inject/memory 911 # echo -12 > actions/MEM_GOING_OFFLINE/error 912 # echo offline > /sys/devices/system/memory/memoryXXX/state 913 bash: echo: write error: Cannot allocate memory 914 915 To compile this code as a module, choose M here: the module will 916 be called memory-notifier-error-inject. 917 918 If unsure, say N. 919 920config DEBUG_PER_CPU_MAPS 921 bool "Debug access to per_cpu maps" 922 depends on DEBUG_KERNEL 923 depends on SMP 924 help 925 Say Y to verify that the per_cpu map being accessed has 926 been set up. This adds a fair amount of code to kernel memory 927 and decreases performance. 928 929 Say N if unsure. 930 931config DEBUG_KMAP_LOCAL 932 bool "Debug kmap_local temporary mappings" 933 depends on DEBUG_KERNEL && KMAP_LOCAL 934 help 935 This option enables additional error checking for the kmap_local 936 infrastructure. Disable for production use. 937 938config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 939 bool 940 941config DEBUG_KMAP_LOCAL_FORCE_MAP 942 bool "Enforce kmap_local temporary mappings" 943 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 944 select KMAP_LOCAL 945 select DEBUG_KMAP_LOCAL 946 help 947 This option enforces temporary mappings through the kmap_local 948 mechanism for non-highmem pages and on non-highmem systems. 949 Disable this for production systems! 950 951config DEBUG_HIGHMEM 952 bool "Highmem debugging" 953 depends on DEBUG_KERNEL && HIGHMEM 954 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 955 select DEBUG_KMAP_LOCAL 956 help 957 This option enables additional error checking for high memory 958 systems. Disable for production systems. 959 960config HAVE_DEBUG_STACKOVERFLOW 961 bool 962 963config DEBUG_STACKOVERFLOW 964 bool "Check for stack overflows" 965 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 966 help 967 Say Y here if you want to check for overflows of kernel, IRQ 968 and exception stacks (if your architecture uses them). This 969 option will show detailed messages if free stack space drops 970 below a certain limit. 971 972 These kinds of bugs usually occur when call-chains in the 973 kernel get too deep, especially when interrupts are 974 involved. 975 976 Use this in cases where you see apparently random memory 977 corruption, especially if it appears in 'struct thread_info' 978 979 If in doubt, say "N". 980 981source "lib/Kconfig.kasan" 982source "lib/Kconfig.kfence" 983 984endmenu # "Memory Debugging" 985 986config DEBUG_SHIRQ 987 bool "Debug shared IRQ handlers" 988 depends on DEBUG_KERNEL 989 help 990 Enable this to generate a spurious interrupt just before a shared 991 interrupt handler is deregistered (generating one when registering 992 is currently disabled). Drivers need to handle this correctly. Some 993 don't and need to be caught. 994 995menu "Debug Oops, Lockups and Hangs" 996 997config PANIC_ON_OOPS 998 bool "Panic on Oops" 999 help 1000 Say Y here to enable the kernel to panic when it oopses. This 1001 has the same effect as setting oops=panic on the kernel command 1002 line. 1003 1004 This feature is useful to ensure that the kernel does not do 1005 anything erroneous after an oops which could result in data 1006 corruption or other issues. 1007 1008 Say N if unsure. 1009 1010config PANIC_ON_OOPS_VALUE 1011 int 1012 range 0 1 1013 default 0 if !PANIC_ON_OOPS 1014 default 1 if PANIC_ON_OOPS 1015 1016config PANIC_TIMEOUT 1017 int "panic timeout" 1018 default 0 1019 help 1020 Set the timeout value (in seconds) until a reboot occurs when 1021 the kernel panics. If n = 0, then we wait forever. A timeout 1022 value n > 0 will wait n seconds before rebooting, while a timeout 1023 value n < 0 will reboot immediately. 1024 1025config LOCKUP_DETECTOR 1026 bool 1027 1028config SOFTLOCKUP_DETECTOR 1029 bool "Detect Soft Lockups" 1030 depends on DEBUG_KERNEL && !S390 1031 select LOCKUP_DETECTOR 1032 help 1033 Say Y here to enable the kernel to act as a watchdog to detect 1034 soft lockups. 1035 1036 Softlockups are bugs that cause the kernel to loop in kernel 1037 mode for more than 20 seconds, without giving other tasks a 1038 chance to run. The current stack trace is displayed upon 1039 detection and the system will stay locked up. 1040 1041config BOOTPARAM_SOFTLOCKUP_PANIC 1042 bool "Panic (Reboot) On Soft Lockups" 1043 depends on SOFTLOCKUP_DETECTOR 1044 help 1045 Say Y here to enable the kernel to panic on "soft lockups", 1046 which are bugs that cause the kernel to loop in kernel 1047 mode for more than 20 seconds (configurable using the watchdog_thresh 1048 sysctl), without giving other tasks a chance to run. 1049 1050 The panic can be used in combination with panic_timeout, 1051 to cause the system to reboot automatically after a 1052 lockup has been detected. This feature is useful for 1053 high-availability systems that have uptime guarantees and 1054 where a lockup must be resolved ASAP. 1055 1056 Say N if unsure. 1057 1058config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 1059 int 1060 depends on SOFTLOCKUP_DETECTOR 1061 range 0 1 1062 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 1063 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 1064 1065config HARDLOCKUP_DETECTOR_PERF 1066 bool 1067 select SOFTLOCKUP_DETECTOR 1068 1069# 1070# Enables a timestamp based low pass filter to compensate for perf based 1071# hard lockup detection which runs too fast due to turbo modes. 1072# 1073config HARDLOCKUP_CHECK_TIMESTAMP 1074 bool 1075 1076# 1077# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1078# lockup detector rather than the perf based detector. 1079# 1080config HARDLOCKUP_DETECTOR 1081 bool "Detect Hard Lockups" 1082 depends on DEBUG_KERNEL && !S390 1083 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1084 select LOCKUP_DETECTOR 1085 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1086 help 1087 Say Y here to enable the kernel to act as a watchdog to detect 1088 hard lockups. 1089 1090 Hardlockups are bugs that cause the CPU to loop in kernel mode 1091 for more than 10 seconds, without letting other interrupts have a 1092 chance to run. The current stack trace is displayed upon detection 1093 and the system will stay locked up. 1094 1095config BOOTPARAM_HARDLOCKUP_PANIC 1096 bool "Panic (Reboot) On Hard Lockups" 1097 depends on HARDLOCKUP_DETECTOR 1098 help 1099 Say Y here to enable the kernel to panic on "hard lockups", 1100 which are bugs that cause the kernel to loop in kernel 1101 mode with interrupts disabled for more than 10 seconds (configurable 1102 using the watchdog_thresh sysctl). 1103 1104 Say N if unsure. 1105 1106config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1107 int 1108 depends on HARDLOCKUP_DETECTOR 1109 range 0 1 1110 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1111 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1112 1113config DETECT_HUNG_TASK 1114 bool "Detect Hung Tasks" 1115 depends on DEBUG_KERNEL 1116 default SOFTLOCKUP_DETECTOR 1117 help 1118 Say Y here to enable the kernel to detect "hung tasks", 1119 which are bugs that cause the task to be stuck in 1120 uninterruptible "D" state indefinitely. 1121 1122 When a hung task is detected, the kernel will print the 1123 current stack trace (which you should report), but the 1124 task will stay in uninterruptible state. If lockdep is 1125 enabled then all held locks will also be reported. This 1126 feature has negligible overhead. 1127 1128config DEFAULT_HUNG_TASK_TIMEOUT 1129 int "Default timeout for hung task detection (in seconds)" 1130 depends on DETECT_HUNG_TASK 1131 default 120 1132 help 1133 This option controls the default timeout (in seconds) used 1134 to determine when a task has become non-responsive and should 1135 be considered hung. 1136 1137 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1138 sysctl or by writing a value to 1139 /proc/sys/kernel/hung_task_timeout_secs. 1140 1141 A timeout of 0 disables the check. The default is two minutes. 1142 Keeping the default should be fine in most cases. 1143 1144config BOOTPARAM_HUNG_TASK_PANIC 1145 bool "Panic (Reboot) On Hung Tasks" 1146 depends on DETECT_HUNG_TASK 1147 help 1148 Say Y here to enable the kernel to panic on "hung tasks", 1149 which are bugs that cause the kernel to leave a task stuck 1150 in uninterruptible "D" state. 1151 1152 The panic can be used in combination with panic_timeout, 1153 to cause the system to reboot automatically after a 1154 hung task has been detected. This feature is useful for 1155 high-availability systems that have uptime guarantees and 1156 where a hung tasks must be resolved ASAP. 1157 1158 Say N if unsure. 1159 1160config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1161 int 1162 depends on DETECT_HUNG_TASK 1163 range 0 1 1164 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1165 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1166 1167config WQ_WATCHDOG 1168 bool "Detect Workqueue Stalls" 1169 depends on DEBUG_KERNEL 1170 help 1171 Say Y here to enable stall detection on workqueues. If a 1172 worker pool doesn't make forward progress on a pending work 1173 item for over a given amount of time, 30s by default, a 1174 warning message is printed along with dump of workqueue 1175 state. This can be configured through kernel parameter 1176 "workqueue.watchdog_thresh" and its sysfs counterpart. 1177 1178config TEST_LOCKUP 1179 tristate "Test module to generate lockups" 1180 depends on m 1181 help 1182 This builds the "test_lockup" module that helps to make sure 1183 that watchdogs and lockup detectors are working properly. 1184 1185 Depending on module parameters it could emulate soft or hard 1186 lockup, "hung task", or locking arbitrary lock for a long time. 1187 Also it could generate series of lockups with cooling-down periods. 1188 1189 If unsure, say N. 1190 1191endmenu # "Debug lockups and hangs" 1192 1193menu "Scheduler Debugging" 1194 1195config SCHED_DEBUG 1196 bool "Collect scheduler debugging info" 1197 depends on DEBUG_KERNEL && PROC_FS 1198 default y 1199 help 1200 If you say Y here, the /proc/sched_debug file will be provided 1201 that can help debug the scheduler. The runtime overhead of this 1202 option is minimal. 1203 1204config SCHED_INFO 1205 bool 1206 default n 1207 1208config SCHEDSTATS 1209 bool "Collect scheduler statistics" 1210 depends on DEBUG_KERNEL && PROC_FS 1211 select SCHED_INFO 1212 help 1213 If you say Y here, additional code will be inserted into the 1214 scheduler and related routines to collect statistics about 1215 scheduler behavior and provide them in /proc/schedstat. These 1216 stats may be useful for both tuning and debugging the scheduler 1217 If you aren't debugging the scheduler or trying to tune a specific 1218 application, you can say N to avoid the very slight overhead 1219 this adds. 1220 1221endmenu 1222 1223config DEBUG_TIMEKEEPING 1224 bool "Enable extra timekeeping sanity checking" 1225 help 1226 This option will enable additional timekeeping sanity checks 1227 which may be helpful when diagnosing issues where timekeeping 1228 problems are suspected. 1229 1230 This may include checks in the timekeeping hotpaths, so this 1231 option may have a (very small) performance impact to some 1232 workloads. 1233 1234 If unsure, say N. 1235 1236config DEBUG_PREEMPT 1237 bool "Debug preemptible kernel" 1238 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1239 help 1240 If you say Y here then the kernel will use a debug variant of the 1241 commonly used smp_processor_id() function and will print warnings 1242 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1243 will detect preemption count underflows. 1244 1245 This option has potential to introduce high runtime overhead, 1246 depending on workload as it triggers debugging routines for each 1247 this_cpu operation. It should only be used for debugging purposes. 1248 1249menu "Lock Debugging (spinlocks, mutexes, etc...)" 1250 1251config LOCK_DEBUGGING_SUPPORT 1252 bool 1253 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1254 default y 1255 1256config PROVE_LOCKING 1257 bool "Lock debugging: prove locking correctness" 1258 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1259 select LOCKDEP 1260 select DEBUG_SPINLOCK 1261 select DEBUG_MUTEXES if !PREEMPT_RT 1262 select DEBUG_RT_MUTEXES if RT_MUTEXES 1263 select DEBUG_RWSEMS 1264 select DEBUG_WW_MUTEX_SLOWPATH 1265 select DEBUG_LOCK_ALLOC 1266 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1267 select TRACE_IRQFLAGS 1268 default n 1269 help 1270 This feature enables the kernel to prove that all locking 1271 that occurs in the kernel runtime is mathematically 1272 correct: that under no circumstance could an arbitrary (and 1273 not yet triggered) combination of observed locking 1274 sequences (on an arbitrary number of CPUs, running an 1275 arbitrary number of tasks and interrupt contexts) cause a 1276 deadlock. 1277 1278 In short, this feature enables the kernel to report locking 1279 related deadlocks before they actually occur. 1280 1281 The proof does not depend on how hard and complex a 1282 deadlock scenario would be to trigger: how many 1283 participant CPUs, tasks and irq-contexts would be needed 1284 for it to trigger. The proof also does not depend on 1285 timing: if a race and a resulting deadlock is possible 1286 theoretically (no matter how unlikely the race scenario 1287 is), it will be proven so and will immediately be 1288 reported by the kernel (once the event is observed that 1289 makes the deadlock theoretically possible). 1290 1291 If a deadlock is impossible (i.e. the locking rules, as 1292 observed by the kernel, are mathematically correct), the 1293 kernel reports nothing. 1294 1295 NOTE: this feature can also be enabled for rwlocks, mutexes 1296 and rwsems - in which case all dependencies between these 1297 different locking variants are observed and mapped too, and 1298 the proof of observed correctness is also maintained for an 1299 arbitrary combination of these separate locking variants. 1300 1301 For more details, see Documentation/locking/lockdep-design.rst. 1302 1303config PROVE_RAW_LOCK_NESTING 1304 bool "Enable raw_spinlock - spinlock nesting checks" 1305 depends on PROVE_LOCKING 1306 default n 1307 help 1308 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1309 that the lock nesting rules for PREEMPT_RT enabled kernels are 1310 not violated. 1311 1312 NOTE: There are known nesting problems. So if you enable this 1313 option expect lockdep splats until these problems have been fully 1314 addressed which is work in progress. This config switch allows to 1315 identify and analyze these problems. It will be removed and the 1316 check permanently enabled once the main issues have been fixed. 1317 1318 If unsure, select N. 1319 1320config LOCK_STAT 1321 bool "Lock usage statistics" 1322 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1323 select LOCKDEP 1324 select DEBUG_SPINLOCK 1325 select DEBUG_MUTEXES if !PREEMPT_RT 1326 select DEBUG_RT_MUTEXES if RT_MUTEXES 1327 select DEBUG_LOCK_ALLOC 1328 default n 1329 help 1330 This feature enables tracking lock contention points 1331 1332 For more details, see Documentation/locking/lockstat.rst 1333 1334 This also enables lock events required by "perf lock", 1335 subcommand of perf. 1336 If you want to use "perf lock", you also need to turn on 1337 CONFIG_EVENT_TRACING. 1338 1339 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1340 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1341 1342config DEBUG_RT_MUTEXES 1343 bool "RT Mutex debugging, deadlock detection" 1344 depends on DEBUG_KERNEL && RT_MUTEXES 1345 help 1346 This allows rt mutex semantics violations and rt mutex related 1347 deadlocks (lockups) to be detected and reported automatically. 1348 1349config DEBUG_SPINLOCK 1350 bool "Spinlock and rw-lock debugging: basic checks" 1351 depends on DEBUG_KERNEL 1352 select UNINLINE_SPIN_UNLOCK 1353 help 1354 Say Y here and build SMP to catch missing spinlock initialization 1355 and certain other kinds of spinlock errors commonly made. This is 1356 best used in conjunction with the NMI watchdog so that spinlock 1357 deadlocks are also debuggable. 1358 1359config DEBUG_MUTEXES 1360 bool "Mutex debugging: basic checks" 1361 depends on DEBUG_KERNEL && !PREEMPT_RT 1362 help 1363 This feature allows mutex semantics violations to be detected and 1364 reported. 1365 1366config DEBUG_WW_MUTEX_SLOWPATH 1367 bool "Wait/wound mutex debugging: Slowpath testing" 1368 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1369 select DEBUG_LOCK_ALLOC 1370 select DEBUG_SPINLOCK 1371 select DEBUG_MUTEXES if !PREEMPT_RT 1372 select DEBUG_RT_MUTEXES if PREEMPT_RT 1373 help 1374 This feature enables slowpath testing for w/w mutex users by 1375 injecting additional -EDEADLK wound/backoff cases. Together with 1376 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1377 will test all possible w/w mutex interface abuse with the 1378 exception of simply not acquiring all the required locks. 1379 Note that this feature can introduce significant overhead, so 1380 it really should not be enabled in a production or distro kernel, 1381 even a debug kernel. If you are a driver writer, enable it. If 1382 you are a distro, do not. 1383 1384config DEBUG_RWSEMS 1385 bool "RW Semaphore debugging: basic checks" 1386 depends on DEBUG_KERNEL 1387 help 1388 This debugging feature allows mismatched rw semaphore locks 1389 and unlocks to be detected and reported. 1390 1391config DEBUG_LOCK_ALLOC 1392 bool "Lock debugging: detect incorrect freeing of live locks" 1393 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1394 select DEBUG_SPINLOCK 1395 select DEBUG_MUTEXES if !PREEMPT_RT 1396 select DEBUG_RT_MUTEXES if RT_MUTEXES 1397 select LOCKDEP 1398 help 1399 This feature will check whether any held lock (spinlock, rwlock, 1400 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1401 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1402 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1403 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1404 held during task exit. 1405 1406config LOCKDEP 1407 bool 1408 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1409 select STACKTRACE 1410 select KALLSYMS 1411 select KALLSYMS_ALL 1412 1413config LOCKDEP_SMALL 1414 bool 1415 1416config LOCKDEP_BITS 1417 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1418 depends on LOCKDEP && !LOCKDEP_SMALL 1419 range 10 30 1420 default 15 1421 help 1422 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1423 1424config LOCKDEP_CHAINS_BITS 1425 int "Bitsize for MAX_LOCKDEP_CHAINS" 1426 depends on LOCKDEP && !LOCKDEP_SMALL 1427 range 10 30 1428 default 16 1429 help 1430 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1431 1432config LOCKDEP_STACK_TRACE_BITS 1433 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1434 depends on LOCKDEP && !LOCKDEP_SMALL 1435 range 10 30 1436 default 19 1437 help 1438 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1439 1440config LOCKDEP_STACK_TRACE_HASH_BITS 1441 int "Bitsize for STACK_TRACE_HASH_SIZE" 1442 depends on LOCKDEP && !LOCKDEP_SMALL 1443 range 10 30 1444 default 14 1445 help 1446 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1447 1448config LOCKDEP_CIRCULAR_QUEUE_BITS 1449 int "Bitsize for elements in circular_queue struct" 1450 depends on LOCKDEP 1451 range 10 30 1452 default 12 1453 help 1454 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1455 1456config DEBUG_LOCKDEP 1457 bool "Lock dependency engine debugging" 1458 depends on DEBUG_KERNEL && LOCKDEP 1459 select DEBUG_IRQFLAGS 1460 help 1461 If you say Y here, the lock dependency engine will do 1462 additional runtime checks to debug itself, at the price 1463 of more runtime overhead. 1464 1465config DEBUG_ATOMIC_SLEEP 1466 bool "Sleep inside atomic section checking" 1467 select PREEMPT_COUNT 1468 depends on DEBUG_KERNEL 1469 depends on !ARCH_NO_PREEMPT 1470 help 1471 If you say Y here, various routines which may sleep will become very 1472 noisy if they are called inside atomic sections: when a spinlock is 1473 held, inside an rcu read side critical section, inside preempt disabled 1474 sections, inside an interrupt, etc... 1475 1476config DEBUG_LOCKING_API_SELFTESTS 1477 bool "Locking API boot-time self-tests" 1478 depends on DEBUG_KERNEL 1479 help 1480 Say Y here if you want the kernel to run a short self-test during 1481 bootup. The self-test checks whether common types of locking bugs 1482 are detected by debugging mechanisms or not. (if you disable 1483 lock debugging then those bugs won't be detected of course.) 1484 The following locking APIs are covered: spinlocks, rwlocks, 1485 mutexes and rwsems. 1486 1487config LOCK_TORTURE_TEST 1488 tristate "torture tests for locking" 1489 depends on DEBUG_KERNEL 1490 select TORTURE_TEST 1491 help 1492 This option provides a kernel module that runs torture tests 1493 on kernel locking primitives. The kernel module may be built 1494 after the fact on the running kernel to be tested, if desired. 1495 1496 Say Y here if you want kernel locking-primitive torture tests 1497 to be built into the kernel. 1498 Say M if you want these torture tests to build as a module. 1499 Say N if you are unsure. 1500 1501config WW_MUTEX_SELFTEST 1502 tristate "Wait/wound mutex selftests" 1503 help 1504 This option provides a kernel module that runs tests on the 1505 on the struct ww_mutex locking API. 1506 1507 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1508 with this test harness. 1509 1510 Say M if you want these self tests to build as a module. 1511 Say N if you are unsure. 1512 1513config SCF_TORTURE_TEST 1514 tristate "torture tests for smp_call_function*()" 1515 depends on DEBUG_KERNEL 1516 select TORTURE_TEST 1517 help 1518 This option provides a kernel module that runs torture tests 1519 on the smp_call_function() family of primitives. The kernel 1520 module may be built after the fact on the running kernel to 1521 be tested, if desired. 1522 1523config CSD_LOCK_WAIT_DEBUG 1524 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1525 depends on DEBUG_KERNEL 1526 depends on 64BIT 1527 default n 1528 help 1529 This option enables debug prints when CPUs are slow to respond 1530 to the smp_call_function*() IPI wrappers. These debug prints 1531 include the IPI handler function currently executing (if any) 1532 and relevant stack traces. 1533 1534endmenu # lock debugging 1535 1536config TRACE_IRQFLAGS 1537 depends on TRACE_IRQFLAGS_SUPPORT 1538 bool 1539 help 1540 Enables hooks to interrupt enabling and disabling for 1541 either tracing or lock debugging. 1542 1543config TRACE_IRQFLAGS_NMI 1544 def_bool y 1545 depends on TRACE_IRQFLAGS 1546 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1547 1548config DEBUG_IRQFLAGS 1549 bool "Debug IRQ flag manipulation" 1550 help 1551 Enables checks for potentially unsafe enabling or disabling of 1552 interrupts, such as calling raw_local_irq_restore() when interrupts 1553 are enabled. 1554 1555config STACKTRACE 1556 bool "Stack backtrace support" 1557 depends on STACKTRACE_SUPPORT 1558 help 1559 This option causes the kernel to create a /proc/pid/stack for 1560 every process, showing its current stack trace. 1561 It is also used by various kernel debugging features that require 1562 stack trace generation. 1563 1564config WARN_ALL_UNSEEDED_RANDOM 1565 bool "Warn for all uses of unseeded randomness" 1566 default n 1567 help 1568 Some parts of the kernel contain bugs relating to their use of 1569 cryptographically secure random numbers before it's actually possible 1570 to generate those numbers securely. This setting ensures that these 1571 flaws don't go unnoticed, by enabling a message, should this ever 1572 occur. This will allow people with obscure setups to know when things 1573 are going wrong, so that they might contact developers about fixing 1574 it. 1575 1576 Unfortunately, on some models of some architectures getting 1577 a fully seeded CRNG is extremely difficult, and so this can 1578 result in dmesg getting spammed for a surprisingly long 1579 time. This is really bad from a security perspective, and 1580 so architecture maintainers really need to do what they can 1581 to get the CRNG seeded sooner after the system is booted. 1582 However, since users cannot do anything actionable to 1583 address this, by default this option is disabled. 1584 1585 Say Y here if you want to receive warnings for all uses of 1586 unseeded randomness. This will be of use primarily for 1587 those developers interested in improving the security of 1588 Linux kernels running on their architecture (or 1589 subarchitecture). 1590 1591config DEBUG_KOBJECT 1592 bool "kobject debugging" 1593 depends on DEBUG_KERNEL 1594 help 1595 If you say Y here, some extra kobject debugging messages will be sent 1596 to the syslog. 1597 1598config DEBUG_KOBJECT_RELEASE 1599 bool "kobject release debugging" 1600 depends on DEBUG_OBJECTS_TIMERS 1601 help 1602 kobjects are reference counted objects. This means that their 1603 last reference count put is not predictable, and the kobject can 1604 live on past the point at which a driver decides to drop it's 1605 initial reference to the kobject gained on allocation. An 1606 example of this would be a struct device which has just been 1607 unregistered. 1608 1609 However, some buggy drivers assume that after such an operation, 1610 the memory backing the kobject can be immediately freed. This 1611 goes completely against the principles of a refcounted object. 1612 1613 If you say Y here, the kernel will delay the release of kobjects 1614 on the last reference count to improve the visibility of this 1615 kind of kobject release bug. 1616 1617config HAVE_DEBUG_BUGVERBOSE 1618 bool 1619 1620menu "Debug kernel data structures" 1621 1622config DEBUG_LIST 1623 bool "Debug linked list manipulation" 1624 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1625 help 1626 Enable this to turn on extended checks in the linked-list 1627 walking routines. 1628 1629 If unsure, say N. 1630 1631config DEBUG_PLIST 1632 bool "Debug priority linked list manipulation" 1633 depends on DEBUG_KERNEL 1634 help 1635 Enable this to turn on extended checks in the priority-ordered 1636 linked-list (plist) walking routines. This checks the entire 1637 list multiple times during each manipulation. 1638 1639 If unsure, say N. 1640 1641config DEBUG_SG 1642 bool "Debug SG table operations" 1643 depends on DEBUG_KERNEL 1644 help 1645 Enable this to turn on checks on scatter-gather tables. This can 1646 help find problems with drivers that do not properly initialize 1647 their sg tables. 1648 1649 If unsure, say N. 1650 1651config DEBUG_NOTIFIERS 1652 bool "Debug notifier call chains" 1653 depends on DEBUG_KERNEL 1654 help 1655 Enable this to turn on sanity checking for notifier call chains. 1656 This is most useful for kernel developers to make sure that 1657 modules properly unregister themselves from notifier chains. 1658 This is a relatively cheap check but if you care about maximum 1659 performance, say N. 1660 1661config BUG_ON_DATA_CORRUPTION 1662 bool "Trigger a BUG when data corruption is detected" 1663 select DEBUG_LIST 1664 help 1665 Select this option if the kernel should BUG when it encounters 1666 data corruption in kernel memory structures when they get checked 1667 for validity. 1668 1669 If unsure, say N. 1670 1671endmenu 1672 1673config DEBUG_CREDENTIALS 1674 bool "Debug credential management" 1675 depends on DEBUG_KERNEL 1676 help 1677 Enable this to turn on some debug checking for credential 1678 management. The additional code keeps track of the number of 1679 pointers from task_structs to any given cred struct, and checks to 1680 see that this number never exceeds the usage count of the cred 1681 struct. 1682 1683 Furthermore, if SELinux is enabled, this also checks that the 1684 security pointer in the cred struct is never seen to be invalid. 1685 1686 If unsure, say N. 1687 1688source "kernel/rcu/Kconfig.debug" 1689 1690config DEBUG_WQ_FORCE_RR_CPU 1691 bool "Force round-robin CPU selection for unbound work items" 1692 depends on DEBUG_KERNEL 1693 default n 1694 help 1695 Workqueue used to implicitly guarantee that work items queued 1696 without explicit CPU specified are put on the local CPU. This 1697 guarantee is no longer true and while local CPU is still 1698 preferred work items may be put on foreign CPUs. Kernel 1699 parameter "workqueue.debug_force_rr_cpu" is added to force 1700 round-robin CPU selection to flush out usages which depend on the 1701 now broken guarantee. This config option enables the debug 1702 feature by default. When enabled, memory and cache locality will 1703 be impacted. 1704 1705config CPU_HOTPLUG_STATE_CONTROL 1706 bool "Enable CPU hotplug state control" 1707 depends on DEBUG_KERNEL 1708 depends on HOTPLUG_CPU 1709 default n 1710 help 1711 Allows to write steps between "offline" and "online" to the CPUs 1712 sysfs target file so states can be stepped granular. This is a debug 1713 option for now as the hotplug machinery cannot be stopped and 1714 restarted at arbitrary points yet. 1715 1716 Say N if your are unsure. 1717 1718config LATENCYTOP 1719 bool "Latency measuring infrastructure" 1720 depends on DEBUG_KERNEL 1721 depends on STACKTRACE_SUPPORT 1722 depends on PROC_FS 1723 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1724 select KALLSYMS 1725 select KALLSYMS_ALL 1726 select STACKTRACE 1727 select SCHEDSTATS 1728 help 1729 Enable this option if you want to use the LatencyTOP tool 1730 to find out which userspace is blocking on what kernel operations. 1731 1732source "kernel/trace/Kconfig" 1733 1734config PROVIDE_OHCI1394_DMA_INIT 1735 bool "Remote debugging over FireWire early on boot" 1736 depends on PCI && X86 1737 help 1738 If you want to debug problems which hang or crash the kernel early 1739 on boot and the crashing machine has a FireWire port, you can use 1740 this feature to remotely access the memory of the crashed machine 1741 over FireWire. This employs remote DMA as part of the OHCI1394 1742 specification which is now the standard for FireWire controllers. 1743 1744 With remote DMA, you can monitor the printk buffer remotely using 1745 firescope and access all memory below 4GB using fireproxy from gdb. 1746 Even controlling a kernel debugger is possible using remote DMA. 1747 1748 Usage: 1749 1750 If ohci1394_dma=early is used as boot parameter, it will initialize 1751 all OHCI1394 controllers which are found in the PCI config space. 1752 1753 As all changes to the FireWire bus such as enabling and disabling 1754 devices cause a bus reset and thereby disable remote DMA for all 1755 devices, be sure to have the cable plugged and FireWire enabled on 1756 the debugging host before booting the debug target for debugging. 1757 1758 This code (~1k) is freed after boot. By then, the firewire stack 1759 in charge of the OHCI-1394 controllers should be used instead. 1760 1761 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1762 1763source "samples/Kconfig" 1764 1765config ARCH_HAS_DEVMEM_IS_ALLOWED 1766 bool 1767 1768config STRICT_DEVMEM 1769 bool "Filter access to /dev/mem" 1770 depends on MMU && DEVMEM 1771 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1772 default y if PPC || X86 || ARM64 1773 help 1774 If this option is disabled, you allow userspace (root) access to all 1775 of memory, including kernel and userspace memory. Accidental 1776 access to this is obviously disastrous, but specific access can 1777 be used by people debugging the kernel. Note that with PAT support 1778 enabled, even in this case there are restrictions on /dev/mem 1779 use due to the cache aliasing requirements. 1780 1781 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1782 file only allows userspace access to PCI space and the BIOS code and 1783 data regions. This is sufficient for dosemu and X and all common 1784 users of /dev/mem. 1785 1786 If in doubt, say Y. 1787 1788config IO_STRICT_DEVMEM 1789 bool "Filter I/O access to /dev/mem" 1790 depends on STRICT_DEVMEM 1791 help 1792 If this option is disabled, you allow userspace (root) access to all 1793 io-memory regardless of whether a driver is actively using that 1794 range. Accidental access to this is obviously disastrous, but 1795 specific access can be used by people debugging kernel drivers. 1796 1797 If this option is switched on, the /dev/mem file only allows 1798 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1799 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1800 if the driver using a given range cannot be disabled. 1801 1802 If in doubt, say Y. 1803 1804menu "$(SRCARCH) Debugging" 1805 1806source "arch/$(SRCARCH)/Kconfig.debug" 1807 1808endmenu 1809 1810menu "Kernel Testing and Coverage" 1811 1812source "lib/kunit/Kconfig" 1813 1814config NOTIFIER_ERROR_INJECTION 1815 tristate "Notifier error injection" 1816 depends on DEBUG_KERNEL 1817 select DEBUG_FS 1818 help 1819 This option provides the ability to inject artificial errors to 1820 specified notifier chain callbacks. It is useful to test the error 1821 handling of notifier call chain failures. 1822 1823 Say N if unsure. 1824 1825config PM_NOTIFIER_ERROR_INJECT 1826 tristate "PM notifier error injection module" 1827 depends on PM && NOTIFIER_ERROR_INJECTION 1828 default m if PM_DEBUG 1829 help 1830 This option provides the ability to inject artificial errors to 1831 PM notifier chain callbacks. It is controlled through debugfs 1832 interface /sys/kernel/debug/notifier-error-inject/pm 1833 1834 If the notifier call chain should be failed with some events 1835 notified, write the error code to "actions/<notifier event>/error". 1836 1837 Example: Inject PM suspend error (-12 = -ENOMEM) 1838 1839 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1840 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1841 # echo mem > /sys/power/state 1842 bash: echo: write error: Cannot allocate memory 1843 1844 To compile this code as a module, choose M here: the module will 1845 be called pm-notifier-error-inject. 1846 1847 If unsure, say N. 1848 1849config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1850 tristate "OF reconfig notifier error injection module" 1851 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1852 help 1853 This option provides the ability to inject artificial errors to 1854 OF reconfig notifier chain callbacks. It is controlled 1855 through debugfs interface under 1856 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1857 1858 If the notifier call chain should be failed with some events 1859 notified, write the error code to "actions/<notifier event>/error". 1860 1861 To compile this code as a module, choose M here: the module will 1862 be called of-reconfig-notifier-error-inject. 1863 1864 If unsure, say N. 1865 1866config NETDEV_NOTIFIER_ERROR_INJECT 1867 tristate "Netdev notifier error injection module" 1868 depends on NET && NOTIFIER_ERROR_INJECTION 1869 help 1870 This option provides the ability to inject artificial errors to 1871 netdevice notifier chain callbacks. It is controlled through debugfs 1872 interface /sys/kernel/debug/notifier-error-inject/netdev 1873 1874 If the notifier call chain should be failed with some events 1875 notified, write the error code to "actions/<notifier event>/error". 1876 1877 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1878 1879 # cd /sys/kernel/debug/notifier-error-inject/netdev 1880 # echo -22 > actions/NETDEV_CHANGEMTU/error 1881 # ip link set eth0 mtu 1024 1882 RTNETLINK answers: Invalid argument 1883 1884 To compile this code as a module, choose M here: the module will 1885 be called netdev-notifier-error-inject. 1886 1887 If unsure, say N. 1888 1889config FUNCTION_ERROR_INJECTION 1890 bool "Fault-injections of functions" 1891 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1892 help 1893 Add fault injections into various functions that are annotated with 1894 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1895 value of theses functions. This is useful to test error paths of code. 1896 1897 If unsure, say N 1898 1899config FAULT_INJECTION 1900 bool "Fault-injection framework" 1901 depends on DEBUG_KERNEL 1902 help 1903 Provide fault-injection framework. 1904 For more details, see Documentation/fault-injection/. 1905 1906config FAILSLAB 1907 bool "Fault-injection capability for kmalloc" 1908 depends on FAULT_INJECTION 1909 depends on SLAB || SLUB 1910 help 1911 Provide fault-injection capability for kmalloc. 1912 1913config FAIL_PAGE_ALLOC 1914 bool "Fault-injection capability for alloc_pages()" 1915 depends on FAULT_INJECTION 1916 help 1917 Provide fault-injection capability for alloc_pages(). 1918 1919config FAULT_INJECTION_USERCOPY 1920 bool "Fault injection capability for usercopy functions" 1921 depends on FAULT_INJECTION 1922 help 1923 Provides fault-injection capability to inject failures 1924 in usercopy functions (copy_from_user(), get_user(), ...). 1925 1926config FAIL_MAKE_REQUEST 1927 bool "Fault-injection capability for disk IO" 1928 depends on FAULT_INJECTION && BLOCK 1929 help 1930 Provide fault-injection capability for disk IO. 1931 1932config FAIL_IO_TIMEOUT 1933 bool "Fault-injection capability for faking disk interrupts" 1934 depends on FAULT_INJECTION && BLOCK 1935 help 1936 Provide fault-injection capability on end IO handling. This 1937 will make the block layer "forget" an interrupt as configured, 1938 thus exercising the error handling. 1939 1940 Only works with drivers that use the generic timeout handling, 1941 for others it won't do anything. 1942 1943config FAIL_FUTEX 1944 bool "Fault-injection capability for futexes" 1945 select DEBUG_FS 1946 depends on FAULT_INJECTION && FUTEX 1947 help 1948 Provide fault-injection capability for futexes. 1949 1950config FAULT_INJECTION_DEBUG_FS 1951 bool "Debugfs entries for fault-injection capabilities" 1952 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1953 help 1954 Enable configuration of fault-injection capabilities via debugfs. 1955 1956config FAIL_FUNCTION 1957 bool "Fault-injection capability for functions" 1958 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1959 help 1960 Provide function-based fault-injection capability. 1961 This will allow you to override a specific function with a return 1962 with given return value. As a result, function caller will see 1963 an error value and have to handle it. This is useful to test the 1964 error handling in various subsystems. 1965 1966config FAIL_MMC_REQUEST 1967 bool "Fault-injection capability for MMC IO" 1968 depends on FAULT_INJECTION_DEBUG_FS && MMC 1969 help 1970 Provide fault-injection capability for MMC IO. 1971 This will make the mmc core return data errors. This is 1972 useful to test the error handling in the mmc block device 1973 and to test how the mmc host driver handles retries from 1974 the block device. 1975 1976config FAIL_SUNRPC 1977 bool "Fault-injection capability for SunRPC" 1978 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1979 help 1980 Provide fault-injection capability for SunRPC and 1981 its consumers. 1982 1983config FAULT_INJECTION_STACKTRACE_FILTER 1984 bool "stacktrace filter for fault-injection capabilities" 1985 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1986 depends on !X86_64 1987 select STACKTRACE 1988 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1989 help 1990 Provide stacktrace filter for fault-injection capabilities 1991 1992config ARCH_HAS_KCOV 1993 bool 1994 help 1995 An architecture should select this when it can successfully 1996 build and run with CONFIG_KCOV. This typically requires 1997 disabling instrumentation for some early boot code. 1998 1999config CC_HAS_SANCOV_TRACE_PC 2000 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2001 2002 2003config KCOV 2004 bool "Code coverage for fuzzing" 2005 depends on ARCH_HAS_KCOV 2006 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2007 select DEBUG_FS 2008 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2009 help 2010 KCOV exposes kernel code coverage information in a form suitable 2011 for coverage-guided fuzzing (randomized testing). 2012 2013 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2014 different machines and across reboots. If you need stable PC values, 2015 disable RANDOMIZE_BASE. 2016 2017 For more details, see Documentation/dev-tools/kcov.rst. 2018 2019config KCOV_ENABLE_COMPARISONS 2020 bool "Enable comparison operands collection by KCOV" 2021 depends on KCOV 2022 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2023 help 2024 KCOV also exposes operands of every comparison in the instrumented 2025 code along with operand sizes and PCs of the comparison instructions. 2026 These operands can be used by fuzzing engines to improve the quality 2027 of fuzzing coverage. 2028 2029config KCOV_INSTRUMENT_ALL 2030 bool "Instrument all code by default" 2031 depends on KCOV 2032 default y 2033 help 2034 If you are doing generic system call fuzzing (like e.g. syzkaller), 2035 then you will want to instrument the whole kernel and you should 2036 say y here. If you are doing more targeted fuzzing (like e.g. 2037 filesystem fuzzing with AFL) then you will want to enable coverage 2038 for more specific subsets of files, and should say n here. 2039 2040config KCOV_IRQ_AREA_SIZE 2041 hex "Size of interrupt coverage collection area in words" 2042 depends on KCOV 2043 default 0x40000 2044 help 2045 KCOV uses preallocated per-cpu areas to collect coverage from 2046 soft interrupts. This specifies the size of those areas in the 2047 number of unsigned long words. 2048 2049menuconfig RUNTIME_TESTING_MENU 2050 bool "Runtime Testing" 2051 def_bool y 2052 2053if RUNTIME_TESTING_MENU 2054 2055config LKDTM 2056 tristate "Linux Kernel Dump Test Tool Module" 2057 depends on DEBUG_FS 2058 help 2059 This module enables testing of the different dumping mechanisms by 2060 inducing system failures at predefined crash points. 2061 If you don't need it: say N 2062 Choose M here to compile this code as a module. The module will be 2063 called lkdtm. 2064 2065 Documentation on how to use the module can be found in 2066 Documentation/fault-injection/provoke-crashes.rst 2067 2068config TEST_LIST_SORT 2069 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2070 depends on KUNIT 2071 default KUNIT_ALL_TESTS 2072 help 2073 Enable this to turn on 'list_sort()' function test. This test is 2074 executed only once during system boot (so affects only boot time), 2075 or at module load time. 2076 2077 If unsure, say N. 2078 2079config TEST_MIN_HEAP 2080 tristate "Min heap test" 2081 depends on DEBUG_KERNEL || m 2082 help 2083 Enable this to turn on min heap function tests. This test is 2084 executed only once during system boot (so affects only boot time), 2085 or at module load time. 2086 2087 If unsure, say N. 2088 2089config TEST_SORT 2090 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2091 depends on KUNIT 2092 default KUNIT_ALL_TESTS 2093 help 2094 This option enables the self-test function of 'sort()' at boot, 2095 or at module load time. 2096 2097 If unsure, say N. 2098 2099config TEST_DIV64 2100 tristate "64bit/32bit division and modulo test" 2101 depends on DEBUG_KERNEL || m 2102 help 2103 Enable this to turn on 'do_div()' function test. This test is 2104 executed only once during system boot (so affects only boot time), 2105 or at module load time. 2106 2107 If unsure, say N. 2108 2109config KPROBES_SANITY_TEST 2110 bool "Kprobes sanity tests" 2111 depends on DEBUG_KERNEL 2112 depends on KPROBES 2113 help 2114 This option provides for testing basic kprobes functionality on 2115 boot. Samples of kprobe and kretprobe are inserted and 2116 verified for functionality. 2117 2118 Say N if you are unsure. 2119 2120config BACKTRACE_SELF_TEST 2121 tristate "Self test for the backtrace code" 2122 depends on DEBUG_KERNEL 2123 help 2124 This option provides a kernel module that can be used to test 2125 the kernel stack backtrace code. This option is not useful 2126 for distributions or general kernels, but only for kernel 2127 developers working on architecture code. 2128 2129 Note that if you want to also test saved backtraces, you will 2130 have to enable STACKTRACE as well. 2131 2132 Say N if you are unsure. 2133 2134config RBTREE_TEST 2135 tristate "Red-Black tree test" 2136 depends on DEBUG_KERNEL 2137 help 2138 A benchmark measuring the performance of the rbtree library. 2139 Also includes rbtree invariant checks. 2140 2141config REED_SOLOMON_TEST 2142 tristate "Reed-Solomon library test" 2143 depends on DEBUG_KERNEL || m 2144 select REED_SOLOMON 2145 select REED_SOLOMON_ENC16 2146 select REED_SOLOMON_DEC16 2147 help 2148 This option enables the self-test function of rslib at boot, 2149 or at module load time. 2150 2151 If unsure, say N. 2152 2153config INTERVAL_TREE_TEST 2154 tristate "Interval tree test" 2155 depends on DEBUG_KERNEL 2156 select INTERVAL_TREE 2157 help 2158 A benchmark measuring the performance of the interval tree library 2159 2160config PERCPU_TEST 2161 tristate "Per cpu operations test" 2162 depends on m && DEBUG_KERNEL 2163 help 2164 Enable this option to build test module which validates per-cpu 2165 operations. 2166 2167 If unsure, say N. 2168 2169config ATOMIC64_SELFTEST 2170 tristate "Perform an atomic64_t self-test" 2171 help 2172 Enable this option to test the atomic64_t functions at boot or 2173 at module load time. 2174 2175 If unsure, say N. 2176 2177config ASYNC_RAID6_TEST 2178 tristate "Self test for hardware accelerated raid6 recovery" 2179 depends on ASYNC_RAID6_RECOV 2180 select ASYNC_MEMCPY 2181 help 2182 This is a one-shot self test that permutes through the 2183 recovery of all the possible two disk failure scenarios for a 2184 N-disk array. Recovery is performed with the asynchronous 2185 raid6 recovery routines, and will optionally use an offload 2186 engine if one is available. 2187 2188 If unsure, say N. 2189 2190config TEST_HEXDUMP 2191 tristate "Test functions located in the hexdump module at runtime" 2192 2193config STRING_SELFTEST 2194 tristate "Test string functions at runtime" 2195 2196config TEST_STRING_HELPERS 2197 tristate "Test functions located in the string_helpers module at runtime" 2198 2199config TEST_STRSCPY 2200 tristate "Test strscpy*() family of functions at runtime" 2201 2202config TEST_KSTRTOX 2203 tristate "Test kstrto*() family of functions at runtime" 2204 2205config TEST_PRINTF 2206 tristate "Test printf() family of functions at runtime" 2207 2208config TEST_SCANF 2209 tristate "Test scanf() family of functions at runtime" 2210 2211config TEST_BITMAP 2212 tristate "Test bitmap_*() family of functions at runtime" 2213 help 2214 Enable this option to test the bitmap functions at boot. 2215 2216 If unsure, say N. 2217 2218config TEST_UUID 2219 tristate "Test functions located in the uuid module at runtime" 2220 2221config TEST_XARRAY 2222 tristate "Test the XArray code at runtime" 2223 2224config TEST_OVERFLOW 2225 tristate "Test check_*_overflow() functions at runtime" 2226 2227config TEST_RHASHTABLE 2228 tristate "Perform selftest on resizable hash table" 2229 help 2230 Enable this option to test the rhashtable functions at boot. 2231 2232 If unsure, say N. 2233 2234config TEST_HASH 2235 tristate "Perform selftest on hash functions" 2236 help 2237 Enable this option to test the kernel's integer (<linux/hash.h>), 2238 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) 2239 hash functions on boot (or module load). 2240 2241 This is intended to help people writing architecture-specific 2242 optimized versions. If unsure, say N. 2243 2244config TEST_IDA 2245 tristate "Perform selftest on IDA functions" 2246 2247config TEST_PARMAN 2248 tristate "Perform selftest on priority array manager" 2249 depends on PARMAN 2250 help 2251 Enable this option to test priority array manager on boot 2252 (or module load). 2253 2254 If unsure, say N. 2255 2256config TEST_IRQ_TIMINGS 2257 bool "IRQ timings selftest" 2258 depends on IRQ_TIMINGS 2259 help 2260 Enable this option to test the irq timings code on boot. 2261 2262 If unsure, say N. 2263 2264config TEST_LKM 2265 tristate "Test module loading with 'hello world' module" 2266 depends on m 2267 help 2268 This builds the "test_module" module that emits "Hello, world" 2269 on printk when loaded. It is designed to be used for basic 2270 evaluation of the module loading subsystem (for example when 2271 validating module verification). It lacks any extra dependencies, 2272 and will not normally be loaded by the system unless explicitly 2273 requested by name. 2274 2275 If unsure, say N. 2276 2277config TEST_BITOPS 2278 tristate "Test module for compilation of bitops operations" 2279 depends on m 2280 help 2281 This builds the "test_bitops" module that is much like the 2282 TEST_LKM module except that it does a basic exercise of the 2283 set/clear_bit macros and get_count_order/long to make sure there are 2284 no compiler warnings from C=1 sparse checker or -Wextra 2285 compilations. It has no dependencies and doesn't run or load unless 2286 explicitly requested by name. for example: modprobe test_bitops. 2287 2288 If unsure, say N. 2289 2290config TEST_VMALLOC 2291 tristate "Test module for stress/performance analysis of vmalloc allocator" 2292 default n 2293 depends on MMU 2294 depends on m 2295 help 2296 This builds the "test_vmalloc" module that should be used for 2297 stress and performance analysis. So, any new change for vmalloc 2298 subsystem can be evaluated from performance and stability point 2299 of view. 2300 2301 If unsure, say N. 2302 2303config TEST_USER_COPY 2304 tristate "Test user/kernel boundary protections" 2305 depends on m 2306 help 2307 This builds the "test_user_copy" module that runs sanity checks 2308 on the copy_to/from_user infrastructure, making sure basic 2309 user/kernel boundary testing is working. If it fails to load, 2310 a regression has been detected in the user/kernel memory boundary 2311 protections. 2312 2313 If unsure, say N. 2314 2315config TEST_BPF 2316 tristate "Test BPF filter functionality" 2317 depends on m && NET 2318 help 2319 This builds the "test_bpf" module that runs various test vectors 2320 against the BPF interpreter or BPF JIT compiler depending on the 2321 current setting. This is in particular useful for BPF JIT compiler 2322 development, but also to run regression tests against changes in 2323 the interpreter code. It also enables test stubs for eBPF maps and 2324 verifier used by user space verifier testsuite. 2325 2326 If unsure, say N. 2327 2328config TEST_BLACKHOLE_DEV 2329 tristate "Test blackhole netdev functionality" 2330 depends on m && NET 2331 help 2332 This builds the "test_blackhole_dev" module that validates the 2333 data path through this blackhole netdev. 2334 2335 If unsure, say N. 2336 2337config FIND_BIT_BENCHMARK 2338 tristate "Test find_bit functions" 2339 help 2340 This builds the "test_find_bit" module that measure find_*_bit() 2341 functions performance. 2342 2343 If unsure, say N. 2344 2345config TEST_FIRMWARE 2346 tristate "Test firmware loading via userspace interface" 2347 depends on FW_LOADER 2348 help 2349 This builds the "test_firmware" module that creates a userspace 2350 interface for testing firmware loading. This can be used to 2351 control the triggering of firmware loading without needing an 2352 actual firmware-using device. The contents can be rechecked by 2353 userspace. 2354 2355 If unsure, say N. 2356 2357config TEST_SYSCTL 2358 tristate "sysctl test driver" 2359 depends on PROC_SYSCTL 2360 help 2361 This builds the "test_sysctl" module. This driver enables to test the 2362 proc sysctl interfaces available to drivers safely without affecting 2363 production knobs which might alter system functionality. 2364 2365 If unsure, say N. 2366 2367config BITFIELD_KUNIT 2368 tristate "KUnit test bitfield functions at runtime" 2369 depends on KUNIT 2370 help 2371 Enable this option to test the bitfield functions at boot. 2372 2373 KUnit tests run during boot and output the results to the debug log 2374 in TAP format (http://testanything.org/). Only useful for kernel devs 2375 running the KUnit test harness, and not intended for inclusion into a 2376 production build. 2377 2378 For more information on KUnit and unit tests in general please refer 2379 to the KUnit documentation in Documentation/dev-tools/kunit/. 2380 2381 If unsure, say N. 2382 2383config RESOURCE_KUNIT_TEST 2384 tristate "KUnit test for resource API" 2385 depends on KUNIT 2386 help 2387 This builds the resource API unit test. 2388 Tests the logic of API provided by resource.c and ioport.h. 2389 For more information on KUnit and unit tests in general please refer 2390 to the KUnit documentation in Documentation/dev-tools/kunit/. 2391 2392 If unsure, say N. 2393 2394config SYSCTL_KUNIT_TEST 2395 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2396 depends on KUNIT 2397 default KUNIT_ALL_TESTS 2398 help 2399 This builds the proc sysctl unit test, which runs on boot. 2400 Tests the API contract and implementation correctness of sysctl. 2401 For more information on KUnit and unit tests in general please refer 2402 to the KUnit documentation in Documentation/dev-tools/kunit/. 2403 2404 If unsure, say N. 2405 2406config LIST_KUNIT_TEST 2407 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2408 depends on KUNIT 2409 default KUNIT_ALL_TESTS 2410 help 2411 This builds the linked list KUnit test suite. 2412 It tests that the API and basic functionality of the list_head type 2413 and associated macros. 2414 2415 KUnit tests run during boot and output the results to the debug log 2416 in TAP format (https://testanything.org/). Only useful for kernel devs 2417 running the KUnit test harness, and not intended for inclusion into a 2418 production build. 2419 2420 For more information on KUnit and unit tests in general please refer 2421 to the KUnit documentation in Documentation/dev-tools/kunit/. 2422 2423 If unsure, say N. 2424 2425config LINEAR_RANGES_TEST 2426 tristate "KUnit test for linear_ranges" 2427 depends on KUNIT 2428 select LINEAR_RANGES 2429 help 2430 This builds the linear_ranges unit test, which runs on boot. 2431 Tests the linear_ranges logic correctness. 2432 For more information on KUnit and unit tests in general please refer 2433 to the KUnit documentation in Documentation/dev-tools/kunit/. 2434 2435 If unsure, say N. 2436 2437config CMDLINE_KUNIT_TEST 2438 tristate "KUnit test for cmdline API" 2439 depends on KUNIT 2440 help 2441 This builds the cmdline API unit test. 2442 Tests the logic of API provided by cmdline.c. 2443 For more information on KUnit and unit tests in general please refer 2444 to the KUnit documentation in Documentation/dev-tools/kunit/. 2445 2446 If unsure, say N. 2447 2448config BITS_TEST 2449 tristate "KUnit test for bits.h" 2450 depends on KUNIT 2451 help 2452 This builds the bits unit test. 2453 Tests the logic of macros defined in bits.h. 2454 For more information on KUnit and unit tests in general please refer 2455 to the KUnit documentation in Documentation/dev-tools/kunit/. 2456 2457 If unsure, say N. 2458 2459config SLUB_KUNIT_TEST 2460 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2461 depends on SLUB_DEBUG && KUNIT 2462 default KUNIT_ALL_TESTS 2463 help 2464 This builds SLUB allocator unit test. 2465 Tests SLUB cache debugging functionality. 2466 For more information on KUnit and unit tests in general please refer 2467 to the KUnit documentation in Documentation/dev-tools/kunit/. 2468 2469 If unsure, say N. 2470 2471config RATIONAL_KUNIT_TEST 2472 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2473 depends on KUNIT && RATIONAL 2474 default KUNIT_ALL_TESTS 2475 help 2476 This builds the rational math unit test. 2477 For more information on KUnit and unit tests in general please refer 2478 to the KUnit documentation in Documentation/dev-tools/kunit/. 2479 2480 If unsure, say N. 2481 2482config TEST_UDELAY 2483 tristate "udelay test driver" 2484 help 2485 This builds the "udelay_test" module that helps to make sure 2486 that udelay() is working properly. 2487 2488 If unsure, say N. 2489 2490config TEST_STATIC_KEYS 2491 tristate "Test static keys" 2492 depends on m 2493 help 2494 Test the static key interfaces. 2495 2496 If unsure, say N. 2497 2498config TEST_KMOD 2499 tristate "kmod stress tester" 2500 depends on m 2501 depends on NETDEVICES && NET_CORE && INET # for TUN 2502 depends on BLOCK 2503 select TEST_LKM 2504 select XFS_FS 2505 select TUN 2506 select BTRFS_FS 2507 help 2508 Test the kernel's module loading mechanism: kmod. kmod implements 2509 support to load modules using the Linux kernel's usermode helper. 2510 This test provides a series of tests against kmod. 2511 2512 Although technically you can either build test_kmod as a module or 2513 into the kernel we disallow building it into the kernel since 2514 it stress tests request_module() and this will very likely cause 2515 some issues by taking over precious threads available from other 2516 module load requests, ultimately this could be fatal. 2517 2518 To run tests run: 2519 2520 tools/testing/selftests/kmod/kmod.sh --help 2521 2522 If unsure, say N. 2523 2524config TEST_DEBUG_VIRTUAL 2525 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2526 depends on DEBUG_VIRTUAL 2527 help 2528 Test the kernel's ability to detect incorrect calls to 2529 virt_to_phys() done against the non-linear part of the 2530 kernel's virtual address map. 2531 2532 If unsure, say N. 2533 2534config TEST_MEMCAT_P 2535 tristate "Test memcat_p() helper function" 2536 help 2537 Test the memcat_p() helper for correctly merging two 2538 pointer arrays together. 2539 2540 If unsure, say N. 2541 2542config TEST_LIVEPATCH 2543 tristate "Test livepatching" 2544 default n 2545 depends on DYNAMIC_DEBUG 2546 depends on LIVEPATCH 2547 depends on m 2548 help 2549 Test kernel livepatching features for correctness. The tests will 2550 load test modules that will be livepatched in various scenarios. 2551 2552 To run all the livepatching tests: 2553 2554 make -C tools/testing/selftests TARGETS=livepatch run_tests 2555 2556 Alternatively, individual tests may be invoked: 2557 2558 tools/testing/selftests/livepatch/test-callbacks.sh 2559 tools/testing/selftests/livepatch/test-livepatch.sh 2560 tools/testing/selftests/livepatch/test-shadow-vars.sh 2561 2562 If unsure, say N. 2563 2564config TEST_OBJAGG 2565 tristate "Perform selftest on object aggreration manager" 2566 default n 2567 depends on OBJAGG 2568 help 2569 Enable this option to test object aggregation manager on boot 2570 (or module load). 2571 2572 2573config TEST_STACKINIT 2574 tristate "Test level of stack variable initialization" 2575 help 2576 Test if the kernel is zero-initializing stack variables and 2577 padding. Coverage is controlled by compiler flags, 2578 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2579 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2580 2581 If unsure, say N. 2582 2583config TEST_MEMINIT 2584 tristate "Test heap/page initialization" 2585 help 2586 Test if the kernel is zero-initializing heap and page allocations. 2587 This can be useful to test init_on_alloc and init_on_free features. 2588 2589 If unsure, say N. 2590 2591config TEST_HMM 2592 tristate "Test HMM (Heterogeneous Memory Management)" 2593 depends on TRANSPARENT_HUGEPAGE 2594 depends on DEVICE_PRIVATE 2595 select HMM_MIRROR 2596 select MMU_NOTIFIER 2597 help 2598 This is a pseudo device driver solely for testing HMM. 2599 Say M here if you want to build the HMM test module. 2600 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2601 2602 If unsure, say N. 2603 2604config TEST_FREE_PAGES 2605 tristate "Test freeing pages" 2606 help 2607 Test that a memory leak does not occur due to a race between 2608 freeing a block of pages and a speculative page reference. 2609 Loading this module is safe if your kernel has the bug fixed. 2610 If the bug is not fixed, it will leak gigabytes of memory and 2611 probably OOM your system. 2612 2613config TEST_FPU 2614 tristate "Test floating point operations in kernel space" 2615 depends on X86 && !KCOV_INSTRUMENT_ALL 2616 help 2617 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2618 which will trigger a sequence of floating point operations. This is used 2619 for self-testing floating point control register setting in 2620 kernel_fpu_begin(). 2621 2622 If unsure, say N. 2623 2624config TEST_CLOCKSOURCE_WATCHDOG 2625 tristate "Test clocksource watchdog in kernel space" 2626 depends on CLOCKSOURCE_WATCHDOG 2627 help 2628 Enable this option to create a kernel module that will trigger 2629 a test of the clocksource watchdog. This module may be loaded 2630 via modprobe or insmod in which case it will run upon being 2631 loaded, or it may be built in, in which case it will run 2632 shortly after boot. 2633 2634 If unsure, say N. 2635 2636endif # RUNTIME_TESTING_MENU 2637 2638config ARCH_USE_MEMTEST 2639 bool 2640 help 2641 An architecture should select this when it uses early_memtest() 2642 during boot process. 2643 2644config MEMTEST 2645 bool "Memtest" 2646 depends on ARCH_USE_MEMTEST 2647 help 2648 This option adds a kernel parameter 'memtest', which allows memtest 2649 to be set and executed. 2650 memtest=0, mean disabled; -- default 2651 memtest=1, mean do 1 test pattern; 2652 ... 2653 memtest=17, mean do 17 test patterns. 2654 If you are unsure how to answer this question, answer N. 2655 2656 2657 2658config HYPERV_TESTING 2659 bool "Microsoft Hyper-V driver testing" 2660 default n 2661 depends on HYPERV && DEBUG_FS 2662 help 2663 Select this option to enable Hyper-V vmbus testing. 2664 2665endmenu # "Kernel Testing and Coverage" 2666 2667source "Documentation/Kconfig" 2668 2669endmenu # Kernel hacking 2670