1# SPDX-License-Identifier: GPL-2.0-only 2menu "Kernel hacking" 3 4menu "printk and dmesg options" 5 6config PRINTK_TIME 7 bool "Show timing information on printks" 8 depends on PRINTK 9 help 10 Selecting this option causes time stamps of the printk() 11 messages to be added to the output of the syslog() system 12 call and at the console. 13 14 The timestamp is always recorded internally, and exported 15 to /dev/kmsg. This flag just specifies if the timestamp should 16 be included, not that the timestamp is recorded. 17 18 The behavior is also controlled by the kernel command line 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst 20 21config PRINTK_CALLER 22 bool "Show caller information on printks" 23 depends on PRINTK 24 help 25 Selecting this option causes printk() to add a caller "thread id" (if 26 in task context) or a caller "processor id" (if not in task context) 27 to every message. 28 29 This option is intended for environments where multiple threads 30 concurrently call printk() for many times, for it is difficult to 31 interpret without knowing where these lines (or sometimes individual 32 line which was divided into multiple lines due to race) came from. 33 34 Since toggling after boot makes the code racy, currently there is 35 no option to enable/disable at the kernel command line parameter or 36 sysfs interface. 37 38config STACKTRACE_BUILD_ID 39 bool "Show build ID information in stacktraces" 40 depends on PRINTK 41 help 42 Selecting this option adds build ID information for symbols in 43 stacktraces printed with the printk format '%p[SR]b'. 44 45 This option is intended for distros where debuginfo is not easily 46 accessible but can be downloaded given the build ID of the vmlinux or 47 kernel module where the function is located. 48 49config CONSOLE_LOGLEVEL_DEFAULT 50 int "Default console loglevel (1-15)" 51 range 1 15 52 default "7" 53 help 54 Default loglevel to determine what will be printed on the console. 55 56 Setting a default here is equivalent to passing in loglevel=<x> in 57 the kernel bootargs. loglevel=<x> continues to override whatever 58 value is specified here as well. 59 60 Note: This does not affect the log level of un-prefixed printk() 61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT 62 option. 63 64config CONSOLE_LOGLEVEL_QUIET 65 int "quiet console loglevel (1-15)" 66 range 1 15 67 default "4" 68 help 69 loglevel to use when "quiet" is passed on the kernel commandline. 70 71 When "quiet" is passed on the kernel commandline this loglevel 72 will be used as the loglevel. IOW passing "quiet" will be the 73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" 74 75config MESSAGE_LOGLEVEL_DEFAULT 76 int "Default message log level (1-7)" 77 range 1 7 78 default "4" 79 help 80 Default log level for printk statements with no specified priority. 81 82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks 83 that are auditing their logs closely may want to set it to a lower 84 priority. 85 86 Note: This does not affect what message level gets printed on the console 87 by default. To change that, use loglevel=<x> in the kernel bootargs, 88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. 89 90config BOOT_PRINTK_DELAY 91 bool "Delay each boot printk message by N milliseconds" 92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY 93 help 94 This build option allows you to read kernel boot messages 95 by inserting a short delay after each one. The delay is 96 specified in milliseconds on the kernel command line, 97 using "boot_delay=N". 98 99 It is likely that you would also need to use "lpj=M" to preset 100 the "loops per jiffie" value. 101 See a previous boot log for the "lpj" value to use for your 102 system, and then set "lpj=M" before setting "boot_delay=N". 103 NOTE: Using this option may adversely affect SMP systems. 104 I.e., processors other than the first one may not boot up. 105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect 106 what it believes to be lockup conditions. 107 108config DYNAMIC_DEBUG 109 bool "Enable dynamic printk() support" 110 default n 111 depends on PRINTK 112 depends on (DEBUG_FS || PROC_FS) 113 select DYNAMIC_DEBUG_CORE 114 help 115 116 Compiles debug level messages into the kernel, which would not 117 otherwise be available at runtime. These messages can then be 118 enabled/disabled based on various levels of scope - per source file, 119 function, module, format string, and line number. This mechanism 120 implicitly compiles in all pr_debug() and dev_dbg() calls, which 121 enlarges the kernel text size by about 2%. 122 123 If a source file is compiled with DEBUG flag set, any 124 pr_debug() calls in it are enabled by default, but can be 125 disabled at runtime as below. Note that DEBUG flag is 126 turned on by many CONFIG_*DEBUG* options. 127 128 Usage: 129 130 Dynamic debugging is controlled via the 'dynamic_debug/control' file, 131 which is contained in the 'debugfs' filesystem or procfs. 132 Thus, the debugfs or procfs filesystem must first be mounted before 133 making use of this feature. 134 We refer the control file as: <debugfs>/dynamic_debug/control. This 135 file contains a list of the debug statements that can be enabled. The 136 format for each line of the file is: 137 138 filename:lineno [module]function flags format 139 140 filename : source file of the debug statement 141 lineno : line number of the debug statement 142 module : module that contains the debug statement 143 function : function that contains the debug statement 144 flags : '=p' means the line is turned 'on' for printing 145 format : the format used for the debug statement 146 147 From a live system: 148 149 nullarbor:~ # cat <debugfs>/dynamic_debug/control 150 # filename:lineno [module]function flags format 151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" 152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" 153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" 154 155 Example usage: 156 157 // enable the message at line 1603 of file svcsock.c 158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > 159 <debugfs>/dynamic_debug/control 160 161 // enable all the messages in file svcsock.c 162 nullarbor:~ # echo -n 'file svcsock.c +p' > 163 <debugfs>/dynamic_debug/control 164 165 // enable all the messages in the NFS server module 166 nullarbor:~ # echo -n 'module nfsd +p' > 167 <debugfs>/dynamic_debug/control 168 169 // enable all 12 messages in the function svc_process() 170 nullarbor:~ # echo -n 'func svc_process +p' > 171 <debugfs>/dynamic_debug/control 172 173 // disable all 12 messages in the function svc_process() 174 nullarbor:~ # echo -n 'func svc_process -p' > 175 <debugfs>/dynamic_debug/control 176 177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional 178 information. 179 180config DYNAMIC_DEBUG_CORE 181 bool "Enable core function of dynamic debug support" 182 depends on PRINTK 183 depends on (DEBUG_FS || PROC_FS) 184 help 185 Enable core functional support of dynamic debug. It is useful 186 when you want to tie dynamic debug to your kernel modules with 187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for 188 the case of embedded system where the kernel image size is 189 sensitive for people. 190 191config SYMBOLIC_ERRNAME 192 bool "Support symbolic error names in printf" 193 default y if PRINTK 194 help 195 If you say Y here, the kernel's printf implementation will 196 be able to print symbolic error names such as ENOSPC instead 197 of the number 28. It makes the kernel image slightly larger 198 (about 3KB), but can make the kernel logs easier to read. 199 200config DEBUG_BUGVERBOSE 201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT 202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) 203 default y 204 help 205 Say Y here to make BUG() panics output the file name and line number 206 of the BUG call as well as the EIP and oops trace. This aids 207 debugging but costs about 70-100K of memory. 208 209endmenu # "printk and dmesg options" 210 211config DEBUG_KERNEL 212 bool "Kernel debugging" 213 help 214 Say Y here if you are developing drivers or trying to debug and 215 identify kernel problems. 216 217config DEBUG_MISC 218 bool "Miscellaneous debug code" 219 default DEBUG_KERNEL 220 depends on DEBUG_KERNEL 221 help 222 Say Y here if you need to enable miscellaneous debug code that should 223 be under a more specific debug option but isn't. 224 225menu "Compile-time checks and compiler options" 226 227config DEBUG_INFO 228 bool 229 help 230 A kernel debug info option other than "None" has been selected 231 in the "Debug information" choice below, indicating that debug 232 information will be generated for build targets. 233 234choice 235 prompt "Debug information" 236 depends on DEBUG_KERNEL 237 help 238 Selecting something other than "None" results in a kernel image 239 that will include debugging info resulting in a larger kernel image. 240 This adds debug symbols to the kernel and modules (gcc -g), and 241 is needed if you intend to use kernel crashdump or binary object 242 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 243 244 Choose which version of DWARF debug info to emit. If unsure, 245 select "Toolchain default". 246 247config DEBUG_INFO_NONE 248 bool "Disable debug information" 249 help 250 Do not build the kernel with debugging information, which will 251 result in a faster and smaller build. 252 253config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 254 bool "Rely on the toolchain's implicit default DWARF version" 255 select DEBUG_INFO 256 help 257 The implicit default version of DWARF debug info produced by a 258 toolchain changes over time. 259 260 This can break consumers of the debug info that haven't upgraded to 261 support newer revisions, and prevent testing newer versions, but 262 those should be less common scenarios. 263 264config DEBUG_INFO_DWARF4 265 bool "Generate DWARF Version 4 debuginfo" 266 select DEBUG_INFO 267 help 268 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. 269 270 If you have consumers of DWARF debug info that are not ready for 271 newer revisions of DWARF, you may wish to choose this or have your 272 config select this. 273 274config DEBUG_INFO_DWARF5 275 bool "Generate DWARF Version 5 debuginfo" 276 select DEBUG_INFO 277 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) 278 help 279 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 280 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 281 draft features until 7.0), and gdb 8.0+. 282 283 Changes to the structure of debug info in Version 5 allow for around 284 15-18% savings in resulting image and debug info section sizes as 285 compared to DWARF Version 4. DWARF Version 5 standardizes previous 286 extensions such as accelerators for symbol indexing and the format 287 for fission (.dwo/.dwp) files. Users may not want to select this 288 config if they rely on tooling that has not yet been updated to 289 support DWARF Version 5. 290 291endchoice # "Debug information" 292 293if DEBUG_INFO 294 295config DEBUG_INFO_REDUCED 296 bool "Reduce debugging information" 297 help 298 If you say Y here gcc is instructed to generate less debugging 299 information for structure types. This means that tools that 300 need full debugging information (like kgdb or systemtap) won't 301 be happy. But if you merely need debugging information to 302 resolve line numbers there is no loss. Advantage is that 303 build directory object sizes shrink dramatically over a full 304 DEBUG_INFO build and compile times are reduced too. 305 Only works with newer gcc versions. 306 307config DEBUG_INFO_COMPRESSED 308 bool "Compressed debugging information" 309 depends on $(cc-option,-gz=zlib) 310 depends on $(ld-option,--compress-debug-sections=zlib) 311 help 312 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 313 5.0+, binutils 2.26+, and zlib. 314 315 Users of dpkg-deb via scripts/package/builddeb may find an increase in 316 size of their debug .deb packages with this config set, due to the 317 debug info being compressed with zlib, then the object files being 318 recompressed with a different compression scheme. But this is still 319 preferable to setting $KDEB_COMPRESS to "none" which would be even 320 larger. 321 322config DEBUG_INFO_SPLIT 323 bool "Produce split debuginfo in .dwo files" 324 depends on $(cc-option,-gsplit-dwarf) 325 help 326 Generate debug info into separate .dwo files. This significantly 327 reduces the build directory size for builds with DEBUG_INFO, 328 because it stores the information only once on disk in .dwo 329 files instead of multiple times in object files and executables. 330 In addition the debug information is also compressed. 331 332 Requires recent gcc (4.7+) and recent gdb/binutils. 333 Any tool that packages or reads debug information would need 334 to know about the .dwo files and include them. 335 Incompatible with older versions of ccache. 336 337config DEBUG_INFO_BTF 338 bool "Generate BTF typeinfo" 339 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 340 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 341 depends on BPF_SYSCALL 342 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 343 help 344 Generate deduplicated BTF type information from DWARF debug info. 345 Turning this on expects presence of pahole tool, which will convert 346 DWARF type info into equivalent deduplicated BTF type info. 347 348config PAHOLE_HAS_SPLIT_BTF 349 def_bool PAHOLE_VERSION >= 119 350 351config PAHOLE_HAS_BTF_TAG 352 def_bool PAHOLE_VERSION >= 123 353 depends on CC_IS_CLANG 354 help 355 Decide whether pahole emits btf_tag attributes (btf_type_tag and 356 btf_decl_tag) or not. Currently only clang compiler implements 357 these attributes, so make the config depend on CC_IS_CLANG. 358 359config DEBUG_INFO_BTF_MODULES 360 def_bool y 361 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 362 help 363 Generate compact split BTF type information for kernel modules. 364 365config MODULE_ALLOW_BTF_MISMATCH 366 bool "Allow loading modules with non-matching BTF type info" 367 depends on DEBUG_INFO_BTF_MODULES 368 help 369 For modules whose split BTF does not match vmlinux, load without 370 BTF rather than refusing to load. The default behavior with 371 module BTF enabled is to reject modules with such mismatches; 372 this option will still load module BTF where possible but ignore 373 it when a mismatch is found. 374 375config GDB_SCRIPTS 376 bool "Provide GDB scripts for kernel debugging" 377 help 378 This creates the required links to GDB helper scripts in the 379 build directory. If you load vmlinux into gdb, the helper 380 scripts will be automatically imported by gdb as well, and 381 additional functions are available to analyze a Linux kernel 382 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 383 for further details. 384 385endif # DEBUG_INFO 386 387config FRAME_WARN 388 int "Warn for stack frames larger than" 389 range 0 8192 390 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 391 default 2048 if PARISC 392 default 1536 if (!64BIT && XTENSA) 393 default 1024 if !64BIT 394 default 2048 if 64BIT 395 help 396 Tell gcc to warn at build time for stack frames larger than this. 397 Setting this too low will cause a lot of warnings. 398 Setting it to 0 disables the warning. 399 400config STRIP_ASM_SYMS 401 bool "Strip assembler-generated symbols during link" 402 default n 403 help 404 Strip internal assembler-generated symbols during a link (symbols 405 that look like '.Lxxx') so they don't pollute the output of 406 get_wchan() and suchlike. 407 408config READABLE_ASM 409 bool "Generate readable assembler code" 410 depends on DEBUG_KERNEL 411 depends on CC_IS_GCC 412 help 413 Disable some compiler optimizations that tend to generate human unreadable 414 assembler output. This may make the kernel slightly slower, but it helps 415 to keep kernel developers who have to stare a lot at assembler listings 416 sane. 417 418config HEADERS_INSTALL 419 bool "Install uapi headers to usr/include" 420 depends on !UML 421 help 422 This option will install uapi headers (headers exported to user-space) 423 into the usr/include directory for use during the kernel build. 424 This is unneeded for building the kernel itself, but needed for some 425 user-space program samples. It is also needed by some features such 426 as uapi header sanity checks. 427 428config DEBUG_SECTION_MISMATCH 429 bool "Enable full Section mismatch analysis" 430 depends on CC_IS_GCC 431 help 432 The section mismatch analysis checks if there are illegal 433 references from one section to another section. 434 During linktime or runtime, some sections are dropped; 435 any use of code/data previously in these sections would 436 most likely result in an oops. 437 In the code, functions and variables are annotated with 438 __init,, etc. (see the full list in include/linux/init.h), 439 which results in the code/data being placed in specific sections. 440 The section mismatch analysis is always performed after a full 441 kernel build, and enabling this option causes the following 442 additional step to occur: 443 - Add the option -fno-inline-functions-called-once to gcc commands. 444 When inlining a function annotated with __init in a non-init 445 function, we would lose the section information and thus 446 the analysis would not catch the illegal reference. 447 This option tells gcc to inline less (but it does result in 448 a larger kernel). 449 450config SECTION_MISMATCH_WARN_ONLY 451 bool "Make section mismatch errors non-fatal" 452 default y 453 help 454 If you say N here, the build process will fail if there are any 455 section mismatch, instead of just throwing warnings. 456 457 If unsure, say Y. 458 459config DEBUG_FORCE_FUNCTION_ALIGN_64B 460 bool "Force all function address 64B aligned" 461 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 462 help 463 There are cases that a commit from one domain changes the function 464 address alignment of other domains, and cause magic performance 465 bump (regression or improvement). Enable this option will help to 466 verify if the bump is caused by function alignment changes, while 467 it will slightly increase the kernel size and affect icache usage. 468 469 It is mainly for debug and performance tuning use. 470 471# 472# Select this config option from the architecture Kconfig, if it 473# is preferred to always offer frame pointers as a config 474# option on the architecture (regardless of KERNEL_DEBUG): 475# 476config ARCH_WANT_FRAME_POINTERS 477 bool 478 479config FRAME_POINTER 480 bool "Compile the kernel with frame pointers" 481 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 482 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 483 help 484 If you say Y here the resulting kernel image will be slightly 485 larger and slower, but it gives very useful debugging information 486 in case of kernel bugs. (precise oopses/stacktraces/warnings) 487 488config OBJTOOL 489 bool 490 491config STACK_VALIDATION 492 bool "Compile-time stack metadata validation" 493 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 494 select OBJTOOL 495 default n 496 help 497 Validate frame pointer rules at compile-time. This helps ensure that 498 runtime stack traces are more reliable. 499 500 For more information, see 501 tools/objtool/Documentation/stack-validation.txt. 502 503config NOINSTR_VALIDATION 504 bool 505 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 506 select OBJTOOL 507 default y 508 509config VMLINUX_MAP 510 bool "Generate vmlinux.map file when linking" 511 depends on EXPERT 512 help 513 Selecting this option will pass "-Map=vmlinux.map" to ld 514 when linking vmlinux. That file can be useful for verifying 515 and debugging magic section games, and for seeing which 516 pieces of code get eliminated with 517 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 518 519config DEBUG_FORCE_WEAK_PER_CPU 520 bool "Force weak per-cpu definitions" 521 depends on DEBUG_KERNEL 522 help 523 s390 and alpha require percpu variables in modules to be 524 defined weak to work around addressing range issue which 525 puts the following two restrictions on percpu variable 526 definitions. 527 528 1. percpu symbols must be unique whether static or not 529 2. percpu variables can't be defined inside a function 530 531 To ensure that generic code follows the above rules, this 532 option forces all percpu variables to be defined as weak. 533 534endmenu # "Compiler options" 535 536menu "Generic Kernel Debugging Instruments" 537 538config MAGIC_SYSRQ 539 bool "Magic SysRq key" 540 depends on !UML 541 help 542 If you say Y here, you will have some control over the system even 543 if the system crashes for example during kernel debugging (e.g., you 544 will be able to flush the buffer cache to disk, reboot the system 545 immediately or dump some status information). This is accomplished 546 by pressing various keys while holding SysRq (Alt+PrintScreen). It 547 also works on a serial console (on PC hardware at least), if you 548 send a BREAK and then within 5 seconds a command keypress. The 549 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 550 Don't say Y unless you really know what this hack does. 551 552config MAGIC_SYSRQ_DEFAULT_ENABLE 553 hex "Enable magic SysRq key functions by default" 554 depends on MAGIC_SYSRQ 555 default 0x1 556 help 557 Specifies which SysRq key functions are enabled by default. 558 This may be set to 1 or 0 to enable or disable them all, or 559 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 560 561config MAGIC_SYSRQ_SERIAL 562 bool "Enable magic SysRq key over serial" 563 depends on MAGIC_SYSRQ 564 default y 565 help 566 Many embedded boards have a disconnected TTL level serial which can 567 generate some garbage that can lead to spurious false sysrq detects. 568 This option allows you to decide whether you want to enable the 569 magic SysRq key. 570 571config MAGIC_SYSRQ_SERIAL_SEQUENCE 572 string "Char sequence that enables magic SysRq over serial" 573 depends on MAGIC_SYSRQ_SERIAL 574 default "" 575 help 576 Specifies a sequence of characters that can follow BREAK to enable 577 SysRq on a serial console. 578 579 If unsure, leave an empty string and the option will not be enabled. 580 581config DEBUG_FS 582 bool "Debug Filesystem" 583 help 584 debugfs is a virtual file system that kernel developers use to put 585 debugging files into. Enable this option to be able to read and 586 write to these files. 587 588 For detailed documentation on the debugfs API, see 589 Documentation/filesystems/. 590 591 If unsure, say N. 592 593choice 594 prompt "Debugfs default access" 595 depends on DEBUG_FS 596 default DEBUG_FS_ALLOW_ALL 597 help 598 This selects the default access restrictions for debugfs. 599 It can be overridden with kernel command line option 600 debugfs=[on,no-mount,off]. The restrictions apply for API access 601 and filesystem registration. 602 603config DEBUG_FS_ALLOW_ALL 604 bool "Access normal" 605 help 606 No restrictions apply. Both API and filesystem registration 607 is on. This is the normal default operation. 608 609config DEBUG_FS_DISALLOW_MOUNT 610 bool "Do not register debugfs as filesystem" 611 help 612 The API is open but filesystem is not loaded. Clients can still do 613 their work and read with debug tools that do not need 614 debugfs filesystem. 615 616config DEBUG_FS_ALLOW_NONE 617 bool "No access" 618 help 619 Access is off. Clients get -PERM when trying to create nodes in 620 debugfs tree and debugfs is not registered as a filesystem. 621 Client can then back-off or continue without debugfs access. 622 623endchoice 624 625source "lib/Kconfig.kgdb" 626source "lib/Kconfig.ubsan" 627source "lib/Kconfig.kcsan" 628 629endmenu 630 631menu "Networking Debugging" 632 633source "net/Kconfig.debug" 634 635endmenu # "Networking Debugging" 636 637menu "Memory Debugging" 638 639source "mm/Kconfig.debug" 640 641config DEBUG_OBJECTS 642 bool "Debug object operations" 643 depends on DEBUG_KERNEL 644 help 645 If you say Y here, additional code will be inserted into the 646 kernel to track the life time of various objects and validate 647 the operations on those objects. 648 649config DEBUG_OBJECTS_SELFTEST 650 bool "Debug objects selftest" 651 depends on DEBUG_OBJECTS 652 help 653 This enables the selftest of the object debug code. 654 655config DEBUG_OBJECTS_FREE 656 bool "Debug objects in freed memory" 657 depends on DEBUG_OBJECTS 658 help 659 This enables checks whether a k/v free operation frees an area 660 which contains an object which has not been deactivated 661 properly. This can make kmalloc/kfree-intensive workloads 662 much slower. 663 664config DEBUG_OBJECTS_TIMERS 665 bool "Debug timer objects" 666 depends on DEBUG_OBJECTS 667 help 668 If you say Y here, additional code will be inserted into the 669 timer routines to track the life time of timer objects and 670 validate the timer operations. 671 672config DEBUG_OBJECTS_WORK 673 bool "Debug work objects" 674 depends on DEBUG_OBJECTS 675 help 676 If you say Y here, additional code will be inserted into the 677 work queue routines to track the life time of work objects and 678 validate the work operations. 679 680config DEBUG_OBJECTS_RCU_HEAD 681 bool "Debug RCU callbacks objects" 682 depends on DEBUG_OBJECTS 683 help 684 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 685 686config DEBUG_OBJECTS_PERCPU_COUNTER 687 bool "Debug percpu counter objects" 688 depends on DEBUG_OBJECTS 689 help 690 If you say Y here, additional code will be inserted into the 691 percpu counter routines to track the life time of percpu counter 692 objects and validate the percpu counter operations. 693 694config DEBUG_OBJECTS_ENABLE_DEFAULT 695 int "debug_objects bootup default value (0-1)" 696 range 0 1 697 default "1" 698 depends on DEBUG_OBJECTS 699 help 700 Debug objects boot parameter default value 701 702config HAVE_DEBUG_KMEMLEAK 703 bool 704 705config DEBUG_KMEMLEAK 706 bool "Kernel memory leak detector" 707 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 708 select DEBUG_FS 709 select STACKTRACE if STACKTRACE_SUPPORT 710 select KALLSYMS 711 select CRC32 712 help 713 Say Y here if you want to enable the memory leak 714 detector. The memory allocation/freeing is traced in a way 715 similar to the Boehm's conservative garbage collector, the 716 difference being that the orphan objects are not freed but 717 only shown in /sys/kernel/debug/kmemleak. Enabling this 718 feature will introduce an overhead to memory 719 allocations. See Documentation/dev-tools/kmemleak.rst for more 720 details. 721 722 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 723 of finding leaks due to the slab objects poisoning. 724 725 In order to access the kmemleak file, debugfs needs to be 726 mounted (usually at /sys/kernel/debug). 727 728config DEBUG_KMEMLEAK_MEM_POOL_SIZE 729 int "Kmemleak memory pool size" 730 depends on DEBUG_KMEMLEAK 731 range 200 1000000 732 default 16000 733 help 734 Kmemleak must track all the memory allocations to avoid 735 reporting false positives. Since memory may be allocated or 736 freed before kmemleak is fully initialised, use a static pool 737 of metadata objects to track such callbacks. After kmemleak is 738 fully initialised, this memory pool acts as an emergency one 739 if slab allocations fail. 740 741config DEBUG_KMEMLEAK_TEST 742 tristate "Simple test for the kernel memory leak detector" 743 depends on DEBUG_KMEMLEAK && m 744 help 745 This option enables a module that explicitly leaks memory. 746 747 If unsure, say N. 748 749config DEBUG_KMEMLEAK_DEFAULT_OFF 750 bool "Default kmemleak to off" 751 depends on DEBUG_KMEMLEAK 752 help 753 Say Y here to disable kmemleak by default. It can then be enabled 754 on the command line via kmemleak=on. 755 756config DEBUG_KMEMLEAK_AUTO_SCAN 757 bool "Enable kmemleak auto scan thread on boot up" 758 default y 759 depends on DEBUG_KMEMLEAK 760 help 761 Depending on the cpu, kmemleak scan may be cpu intensive and can 762 stall user tasks at times. This option enables/disables automatic 763 kmemleak scan at boot up. 764 765 Say N here to disable kmemleak auto scan thread to stop automatic 766 scanning. Disabling this option disables automatic reporting of 767 memory leaks. 768 769 If unsure, say Y. 770 771config DEBUG_STACK_USAGE 772 bool "Stack utilization instrumentation" 773 depends on DEBUG_KERNEL && !IA64 774 help 775 Enables the display of the minimum amount of free stack which each 776 task has ever had available in the sysrq-T and sysrq-P debug output. 777 778 This option will slow down process creation somewhat. 779 780config SCHED_STACK_END_CHECK 781 bool "Detect stack corruption on calls to schedule()" 782 depends on DEBUG_KERNEL 783 default n 784 help 785 This option checks for a stack overrun on calls to schedule(). 786 If the stack end location is found to be over written always panic as 787 the content of the corrupted region can no longer be trusted. 788 This is to ensure no erroneous behaviour occurs which could result in 789 data corruption or a sporadic crash at a later stage once the region 790 is examined. The runtime overhead introduced is minimal. 791 792config ARCH_HAS_DEBUG_VM_PGTABLE 793 bool 794 help 795 An architecture should select this when it can successfully 796 build and run DEBUG_VM_PGTABLE. 797 798config DEBUG_VM 799 bool "Debug VM" 800 depends on DEBUG_KERNEL 801 help 802 Enable this to turn on extended checks in the virtual-memory system 803 that may impact performance. 804 805 If unsure, say N. 806 807config DEBUG_VM_VMACACHE 808 bool "Debug VMA caching" 809 depends on DEBUG_VM 810 help 811 Enable this to turn on VMA caching debug information. Doing so 812 can cause significant overhead, so only enable it in non-production 813 environments. 814 815 If unsure, say N. 816 817config DEBUG_VM_RB 818 bool "Debug VM red-black trees" 819 depends on DEBUG_VM 820 help 821 Enable VM red-black tree debugging information and extra validations. 822 823 If unsure, say N. 824 825config DEBUG_VM_PGFLAGS 826 bool "Debug page-flags operations" 827 depends on DEBUG_VM 828 help 829 Enables extra validation on page flags operations. 830 831 If unsure, say N. 832 833config DEBUG_VM_PGTABLE 834 bool "Debug arch page table for semantics compliance" 835 depends on MMU 836 depends on ARCH_HAS_DEBUG_VM_PGTABLE 837 default y if DEBUG_VM 838 help 839 This option provides a debug method which can be used to test 840 architecture page table helper functions on various platforms in 841 verifying if they comply with expected generic MM semantics. This 842 will help architecture code in making sure that any changes or 843 new additions of these helpers still conform to expected 844 semantics of the generic MM. Platforms will have to opt in for 845 this through ARCH_HAS_DEBUG_VM_PGTABLE. 846 847 If unsure, say N. 848 849config ARCH_HAS_DEBUG_VIRTUAL 850 bool 851 852config DEBUG_VIRTUAL 853 bool "Debug VM translations" 854 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 855 help 856 Enable some costly sanity checks in virtual to page code. This can 857 catch mistakes with virt_to_page() and friends. 858 859 If unsure, say N. 860 861config DEBUG_NOMMU_REGIONS 862 bool "Debug the global anon/private NOMMU mapping region tree" 863 depends on DEBUG_KERNEL && !MMU 864 help 865 This option causes the global tree of anonymous and private mapping 866 regions to be regularly checked for invalid topology. 867 868config DEBUG_MEMORY_INIT 869 bool "Debug memory initialisation" if EXPERT 870 default !EXPERT 871 help 872 Enable this for additional checks during memory initialisation. 873 The sanity checks verify aspects of the VM such as the memory model 874 and other information provided by the architecture. Verbose 875 information will be printed at KERN_DEBUG loglevel depending 876 on the mminit_loglevel= command-line option. 877 878 If unsure, say Y 879 880config MEMORY_NOTIFIER_ERROR_INJECT 881 tristate "Memory hotplug notifier error injection module" 882 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 883 help 884 This option provides the ability to inject artificial errors to 885 memory hotplug notifier chain callbacks. It is controlled through 886 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 887 888 If the notifier call chain should be failed with some events 889 notified, write the error code to "actions/<notifier event>/error". 890 891 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 892 893 # cd /sys/kernel/debug/notifier-error-inject/memory 894 # echo -12 > actions/MEM_GOING_OFFLINE/error 895 # echo offline > /sys/devices/system/memory/memoryXXX/state 896 bash: echo: write error: Cannot allocate memory 897 898 To compile this code as a module, choose M here: the module will 899 be called memory-notifier-error-inject. 900 901 If unsure, say N. 902 903config DEBUG_PER_CPU_MAPS 904 bool "Debug access to per_cpu maps" 905 depends on DEBUG_KERNEL 906 depends on SMP 907 help 908 Say Y to verify that the per_cpu map being accessed has 909 been set up. This adds a fair amount of code to kernel memory 910 and decreases performance. 911 912 Say N if unsure. 913 914config DEBUG_KMAP_LOCAL 915 bool "Debug kmap_local temporary mappings" 916 depends on DEBUG_KERNEL && KMAP_LOCAL 917 help 918 This option enables additional error checking for the kmap_local 919 infrastructure. Disable for production use. 920 921config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 922 bool 923 924config DEBUG_KMAP_LOCAL_FORCE_MAP 925 bool "Enforce kmap_local temporary mappings" 926 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 927 select KMAP_LOCAL 928 select DEBUG_KMAP_LOCAL 929 help 930 This option enforces temporary mappings through the kmap_local 931 mechanism for non-highmem pages and on non-highmem systems. 932 Disable this for production systems! 933 934config DEBUG_HIGHMEM 935 bool "Highmem debugging" 936 depends on DEBUG_KERNEL && HIGHMEM 937 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 938 select DEBUG_KMAP_LOCAL 939 help 940 This option enables additional error checking for high memory 941 systems. Disable for production systems. 942 943config HAVE_DEBUG_STACKOVERFLOW 944 bool 945 946config DEBUG_STACKOVERFLOW 947 bool "Check for stack overflows" 948 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 949 help 950 Say Y here if you want to check for overflows of kernel, IRQ 951 and exception stacks (if your architecture uses them). This 952 option will show detailed messages if free stack space drops 953 below a certain limit. 954 955 These kinds of bugs usually occur when call-chains in the 956 kernel get too deep, especially when interrupts are 957 involved. 958 959 Use this in cases where you see apparently random memory 960 corruption, especially if it appears in 'struct thread_info' 961 962 If in doubt, say "N". 963 964source "lib/Kconfig.kasan" 965source "lib/Kconfig.kfence" 966 967endmenu # "Memory Debugging" 968 969config DEBUG_SHIRQ 970 bool "Debug shared IRQ handlers" 971 depends on DEBUG_KERNEL 972 help 973 Enable this to generate a spurious interrupt just before a shared 974 interrupt handler is deregistered (generating one when registering 975 is currently disabled). Drivers need to handle this correctly. Some 976 don't and need to be caught. 977 978menu "Debug Oops, Lockups and Hangs" 979 980config PANIC_ON_OOPS 981 bool "Panic on Oops" 982 help 983 Say Y here to enable the kernel to panic when it oopses. This 984 has the same effect as setting oops=panic on the kernel command 985 line. 986 987 This feature is useful to ensure that the kernel does not do 988 anything erroneous after an oops which could result in data 989 corruption or other issues. 990 991 Say N if unsure. 992 993config PANIC_ON_OOPS_VALUE 994 int 995 range 0 1 996 default 0 if !PANIC_ON_OOPS 997 default 1 if PANIC_ON_OOPS 998 999config PANIC_TIMEOUT 1000 int "panic timeout" 1001 default 0 1002 help 1003 Set the timeout value (in seconds) until a reboot occurs when 1004 the kernel panics. If n = 0, then we wait forever. A timeout 1005 value n > 0 will wait n seconds before rebooting, while a timeout 1006 value n < 0 will reboot immediately. 1007 1008config LOCKUP_DETECTOR 1009 bool 1010 1011config SOFTLOCKUP_DETECTOR 1012 bool "Detect Soft Lockups" 1013 depends on DEBUG_KERNEL && !S390 1014 select LOCKUP_DETECTOR 1015 help 1016 Say Y here to enable the kernel to act as a watchdog to detect 1017 soft lockups. 1018 1019 Softlockups are bugs that cause the kernel to loop in kernel 1020 mode for more than 20 seconds, without giving other tasks a 1021 chance to run. The current stack trace is displayed upon 1022 detection and the system will stay locked up. 1023 1024config BOOTPARAM_SOFTLOCKUP_PANIC 1025 bool "Panic (Reboot) On Soft Lockups" 1026 depends on SOFTLOCKUP_DETECTOR 1027 help 1028 Say Y here to enable the kernel to panic on "soft lockups", 1029 which are bugs that cause the kernel to loop in kernel 1030 mode for more than 20 seconds (configurable using the watchdog_thresh 1031 sysctl), without giving other tasks a chance to run. 1032 1033 The panic can be used in combination with panic_timeout, 1034 to cause the system to reboot automatically after a 1035 lockup has been detected. This feature is useful for 1036 high-availability systems that have uptime guarantees and 1037 where a lockup must be resolved ASAP. 1038 1039 Say N if unsure. 1040 1041config HARDLOCKUP_DETECTOR_PERF 1042 bool 1043 select SOFTLOCKUP_DETECTOR 1044 1045# 1046# Enables a timestamp based low pass filter to compensate for perf based 1047# hard lockup detection which runs too fast due to turbo modes. 1048# 1049config HARDLOCKUP_CHECK_TIMESTAMP 1050 bool 1051 1052# 1053# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1054# lockup detector rather than the perf based detector. 1055# 1056config HARDLOCKUP_DETECTOR 1057 bool "Detect Hard Lockups" 1058 depends on DEBUG_KERNEL && !S390 1059 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1060 select LOCKUP_DETECTOR 1061 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1062 help 1063 Say Y here to enable the kernel to act as a watchdog to detect 1064 hard lockups. 1065 1066 Hardlockups are bugs that cause the CPU to loop in kernel mode 1067 for more than 10 seconds, without letting other interrupts have a 1068 chance to run. The current stack trace is displayed upon detection 1069 and the system will stay locked up. 1070 1071config BOOTPARAM_HARDLOCKUP_PANIC 1072 bool "Panic (Reboot) On Hard Lockups" 1073 depends on HARDLOCKUP_DETECTOR 1074 help 1075 Say Y here to enable the kernel to panic on "hard lockups", 1076 which are bugs that cause the kernel to loop in kernel 1077 mode with interrupts disabled for more than 10 seconds (configurable 1078 using the watchdog_thresh sysctl). 1079 1080 Say N if unsure. 1081 1082config DETECT_HUNG_TASK 1083 bool "Detect Hung Tasks" 1084 depends on DEBUG_KERNEL 1085 default SOFTLOCKUP_DETECTOR 1086 help 1087 Say Y here to enable the kernel to detect "hung tasks", 1088 which are bugs that cause the task to be stuck in 1089 uninterruptible "D" state indefinitely. 1090 1091 When a hung task is detected, the kernel will print the 1092 current stack trace (which you should report), but the 1093 task will stay in uninterruptible state. If lockdep is 1094 enabled then all held locks will also be reported. This 1095 feature has negligible overhead. 1096 1097config DEFAULT_HUNG_TASK_TIMEOUT 1098 int "Default timeout for hung task detection (in seconds)" 1099 depends on DETECT_HUNG_TASK 1100 default 120 1101 help 1102 This option controls the default timeout (in seconds) used 1103 to determine when a task has become non-responsive and should 1104 be considered hung. 1105 1106 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1107 sysctl or by writing a value to 1108 /proc/sys/kernel/hung_task_timeout_secs. 1109 1110 A timeout of 0 disables the check. The default is two minutes. 1111 Keeping the default should be fine in most cases. 1112 1113config BOOTPARAM_HUNG_TASK_PANIC 1114 bool "Panic (Reboot) On Hung Tasks" 1115 depends on DETECT_HUNG_TASK 1116 help 1117 Say Y here to enable the kernel to panic on "hung tasks", 1118 which are bugs that cause the kernel to leave a task stuck 1119 in uninterruptible "D" state. 1120 1121 The panic can be used in combination with panic_timeout, 1122 to cause the system to reboot automatically after a 1123 hung task has been detected. This feature is useful for 1124 high-availability systems that have uptime guarantees and 1125 where a hung tasks must be resolved ASAP. 1126 1127 Say N if unsure. 1128 1129config WQ_WATCHDOG 1130 bool "Detect Workqueue Stalls" 1131 depends on DEBUG_KERNEL 1132 help 1133 Say Y here to enable stall detection on workqueues. If a 1134 worker pool doesn't make forward progress on a pending work 1135 item for over a given amount of time, 30s by default, a 1136 warning message is printed along with dump of workqueue 1137 state. This can be configured through kernel parameter 1138 "workqueue.watchdog_thresh" and its sysfs counterpart. 1139 1140config TEST_LOCKUP 1141 tristate "Test module to generate lockups" 1142 depends on m 1143 help 1144 This builds the "test_lockup" module that helps to make sure 1145 that watchdogs and lockup detectors are working properly. 1146 1147 Depending on module parameters it could emulate soft or hard 1148 lockup, "hung task", or locking arbitrary lock for a long time. 1149 Also it could generate series of lockups with cooling-down periods. 1150 1151 If unsure, say N. 1152 1153endmenu # "Debug lockups and hangs" 1154 1155menu "Scheduler Debugging" 1156 1157config SCHED_DEBUG 1158 bool "Collect scheduler debugging info" 1159 depends on DEBUG_KERNEL && PROC_FS 1160 default y 1161 help 1162 If you say Y here, the /proc/sched_debug file will be provided 1163 that can help debug the scheduler. The runtime overhead of this 1164 option is minimal. 1165 1166config SCHED_INFO 1167 bool 1168 default n 1169 1170config SCHEDSTATS 1171 bool "Collect scheduler statistics" 1172 depends on DEBUG_KERNEL && PROC_FS 1173 select SCHED_INFO 1174 help 1175 If you say Y here, additional code will be inserted into the 1176 scheduler and related routines to collect statistics about 1177 scheduler behavior and provide them in /proc/schedstat. These 1178 stats may be useful for both tuning and debugging the scheduler 1179 If you aren't debugging the scheduler or trying to tune a specific 1180 application, you can say N to avoid the very slight overhead 1181 this adds. 1182 1183endmenu 1184 1185config DEBUG_TIMEKEEPING 1186 bool "Enable extra timekeeping sanity checking" 1187 help 1188 This option will enable additional timekeeping sanity checks 1189 which may be helpful when diagnosing issues where timekeeping 1190 problems are suspected. 1191 1192 This may include checks in the timekeeping hotpaths, so this 1193 option may have a (very small) performance impact to some 1194 workloads. 1195 1196 If unsure, say N. 1197 1198config DEBUG_PREEMPT 1199 bool "Debug preemptible kernel" 1200 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1201 default y 1202 help 1203 If you say Y here then the kernel will use a debug variant of the 1204 commonly used smp_processor_id() function and will print warnings 1205 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1206 will detect preemption count underflows. 1207 1208menu "Lock Debugging (spinlocks, mutexes, etc...)" 1209 1210config LOCK_DEBUGGING_SUPPORT 1211 bool 1212 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1213 default y 1214 1215config PROVE_LOCKING 1216 bool "Lock debugging: prove locking correctness" 1217 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1218 select LOCKDEP 1219 select DEBUG_SPINLOCK 1220 select DEBUG_MUTEXES if !PREEMPT_RT 1221 select DEBUG_RT_MUTEXES if RT_MUTEXES 1222 select DEBUG_RWSEMS 1223 select DEBUG_WW_MUTEX_SLOWPATH 1224 select DEBUG_LOCK_ALLOC 1225 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1226 select TRACE_IRQFLAGS 1227 default n 1228 help 1229 This feature enables the kernel to prove that all locking 1230 that occurs in the kernel runtime is mathematically 1231 correct: that under no circumstance could an arbitrary (and 1232 not yet triggered) combination of observed locking 1233 sequences (on an arbitrary number of CPUs, running an 1234 arbitrary number of tasks and interrupt contexts) cause a 1235 deadlock. 1236 1237 In short, this feature enables the kernel to report locking 1238 related deadlocks before they actually occur. 1239 1240 The proof does not depend on how hard and complex a 1241 deadlock scenario would be to trigger: how many 1242 participant CPUs, tasks and irq-contexts would be needed 1243 for it to trigger. The proof also does not depend on 1244 timing: if a race and a resulting deadlock is possible 1245 theoretically (no matter how unlikely the race scenario 1246 is), it will be proven so and will immediately be 1247 reported by the kernel (once the event is observed that 1248 makes the deadlock theoretically possible). 1249 1250 If a deadlock is impossible (i.e. the locking rules, as 1251 observed by the kernel, are mathematically correct), the 1252 kernel reports nothing. 1253 1254 NOTE: this feature can also be enabled for rwlocks, mutexes 1255 and rwsems - in which case all dependencies between these 1256 different locking variants are observed and mapped too, and 1257 the proof of observed correctness is also maintained for an 1258 arbitrary combination of these separate locking variants. 1259 1260 For more details, see Documentation/locking/lockdep-design.rst. 1261 1262config PROVE_RAW_LOCK_NESTING 1263 bool "Enable raw_spinlock - spinlock nesting checks" 1264 depends on PROVE_LOCKING 1265 default n 1266 help 1267 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1268 that the lock nesting rules for PREEMPT_RT enabled kernels are 1269 not violated. 1270 1271 NOTE: There are known nesting problems. So if you enable this 1272 option expect lockdep splats until these problems have been fully 1273 addressed which is work in progress. This config switch allows to 1274 identify and analyze these problems. It will be removed and the 1275 check permanently enabled once the main issues have been fixed. 1276 1277 If unsure, select N. 1278 1279config LOCK_STAT 1280 bool "Lock usage statistics" 1281 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1282 select LOCKDEP 1283 select DEBUG_SPINLOCK 1284 select DEBUG_MUTEXES if !PREEMPT_RT 1285 select DEBUG_RT_MUTEXES if RT_MUTEXES 1286 select DEBUG_LOCK_ALLOC 1287 default n 1288 help 1289 This feature enables tracking lock contention points 1290 1291 For more details, see Documentation/locking/lockstat.rst 1292 1293 This also enables lock events required by "perf lock", 1294 subcommand of perf. 1295 If you want to use "perf lock", you also need to turn on 1296 CONFIG_EVENT_TRACING. 1297 1298 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1299 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1300 1301config DEBUG_RT_MUTEXES 1302 bool "RT Mutex debugging, deadlock detection" 1303 depends on DEBUG_KERNEL && RT_MUTEXES 1304 help 1305 This allows rt mutex semantics violations and rt mutex related 1306 deadlocks (lockups) to be detected and reported automatically. 1307 1308config DEBUG_SPINLOCK 1309 bool "Spinlock and rw-lock debugging: basic checks" 1310 depends on DEBUG_KERNEL 1311 select UNINLINE_SPIN_UNLOCK 1312 help 1313 Say Y here and build SMP to catch missing spinlock initialization 1314 and certain other kinds of spinlock errors commonly made. This is 1315 best used in conjunction with the NMI watchdog so that spinlock 1316 deadlocks are also debuggable. 1317 1318config DEBUG_MUTEXES 1319 bool "Mutex debugging: basic checks" 1320 depends on DEBUG_KERNEL && !PREEMPT_RT 1321 help 1322 This feature allows mutex semantics violations to be detected and 1323 reported. 1324 1325config DEBUG_WW_MUTEX_SLOWPATH 1326 bool "Wait/wound mutex debugging: Slowpath testing" 1327 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1328 select DEBUG_LOCK_ALLOC 1329 select DEBUG_SPINLOCK 1330 select DEBUG_MUTEXES if !PREEMPT_RT 1331 select DEBUG_RT_MUTEXES if PREEMPT_RT 1332 help 1333 This feature enables slowpath testing for w/w mutex users by 1334 injecting additional -EDEADLK wound/backoff cases. Together with 1335 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1336 will test all possible w/w mutex interface abuse with the 1337 exception of simply not acquiring all the required locks. 1338 Note that this feature can introduce significant overhead, so 1339 it really should not be enabled in a production or distro kernel, 1340 even a debug kernel. If you are a driver writer, enable it. If 1341 you are a distro, do not. 1342 1343config DEBUG_RWSEMS 1344 bool "RW Semaphore debugging: basic checks" 1345 depends on DEBUG_KERNEL 1346 help 1347 This debugging feature allows mismatched rw semaphore locks 1348 and unlocks to be detected and reported. 1349 1350config DEBUG_LOCK_ALLOC 1351 bool "Lock debugging: detect incorrect freeing of live locks" 1352 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1353 select DEBUG_SPINLOCK 1354 select DEBUG_MUTEXES if !PREEMPT_RT 1355 select DEBUG_RT_MUTEXES if RT_MUTEXES 1356 select LOCKDEP 1357 help 1358 This feature will check whether any held lock (spinlock, rwlock, 1359 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1360 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1361 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1362 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1363 held during task exit. 1364 1365config LOCKDEP 1366 bool 1367 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1368 select STACKTRACE 1369 select KALLSYMS 1370 select KALLSYMS_ALL 1371 1372config LOCKDEP_SMALL 1373 bool 1374 1375config LOCKDEP_BITS 1376 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1377 depends on LOCKDEP && !LOCKDEP_SMALL 1378 range 10 30 1379 default 15 1380 help 1381 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1382 1383config LOCKDEP_CHAINS_BITS 1384 int "Bitsize for MAX_LOCKDEP_CHAINS" 1385 depends on LOCKDEP && !LOCKDEP_SMALL 1386 range 10 30 1387 default 16 1388 help 1389 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1390 1391config LOCKDEP_STACK_TRACE_BITS 1392 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1393 depends on LOCKDEP && !LOCKDEP_SMALL 1394 range 10 30 1395 default 19 1396 help 1397 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1398 1399config LOCKDEP_STACK_TRACE_HASH_BITS 1400 int "Bitsize for STACK_TRACE_HASH_SIZE" 1401 depends on LOCKDEP && !LOCKDEP_SMALL 1402 range 10 30 1403 default 14 1404 help 1405 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1406 1407config LOCKDEP_CIRCULAR_QUEUE_BITS 1408 int "Bitsize for elements in circular_queue struct" 1409 depends on LOCKDEP 1410 range 10 30 1411 default 12 1412 help 1413 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1414 1415config DEBUG_LOCKDEP 1416 bool "Lock dependency engine debugging" 1417 depends on DEBUG_KERNEL && LOCKDEP 1418 select DEBUG_IRQFLAGS 1419 help 1420 If you say Y here, the lock dependency engine will do 1421 additional runtime checks to debug itself, at the price 1422 of more runtime overhead. 1423 1424config DEBUG_ATOMIC_SLEEP 1425 bool "Sleep inside atomic section checking" 1426 select PREEMPT_COUNT 1427 depends on DEBUG_KERNEL 1428 depends on !ARCH_NO_PREEMPT 1429 help 1430 If you say Y here, various routines which may sleep will become very 1431 noisy if they are called inside atomic sections: when a spinlock is 1432 held, inside an rcu read side critical section, inside preempt disabled 1433 sections, inside an interrupt, etc... 1434 1435config DEBUG_LOCKING_API_SELFTESTS 1436 bool "Locking API boot-time self-tests" 1437 depends on DEBUG_KERNEL 1438 help 1439 Say Y here if you want the kernel to run a short self-test during 1440 bootup. The self-test checks whether common types of locking bugs 1441 are detected by debugging mechanisms or not. (if you disable 1442 lock debugging then those bugs won't be detected of course.) 1443 The following locking APIs are covered: spinlocks, rwlocks, 1444 mutexes and rwsems. 1445 1446config LOCK_TORTURE_TEST 1447 tristate "torture tests for locking" 1448 depends on DEBUG_KERNEL 1449 select TORTURE_TEST 1450 help 1451 This option provides a kernel module that runs torture tests 1452 on kernel locking primitives. The kernel module may be built 1453 after the fact on the running kernel to be tested, if desired. 1454 1455 Say Y here if you want kernel locking-primitive torture tests 1456 to be built into the kernel. 1457 Say M if you want these torture tests to build as a module. 1458 Say N if you are unsure. 1459 1460config WW_MUTEX_SELFTEST 1461 tristate "Wait/wound mutex selftests" 1462 help 1463 This option provides a kernel module that runs tests on the 1464 on the struct ww_mutex locking API. 1465 1466 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1467 with this test harness. 1468 1469 Say M if you want these self tests to build as a module. 1470 Say N if you are unsure. 1471 1472config SCF_TORTURE_TEST 1473 tristate "torture tests for smp_call_function*()" 1474 depends on DEBUG_KERNEL 1475 select TORTURE_TEST 1476 help 1477 This option provides a kernel module that runs torture tests 1478 on the smp_call_function() family of primitives. The kernel 1479 module may be built after the fact on the running kernel to 1480 be tested, if desired. 1481 1482config CSD_LOCK_WAIT_DEBUG 1483 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1484 depends on DEBUG_KERNEL 1485 depends on 64BIT 1486 default n 1487 help 1488 This option enables debug prints when CPUs are slow to respond 1489 to the smp_call_function*() IPI wrappers. These debug prints 1490 include the IPI handler function currently executing (if any) 1491 and relevant stack traces. 1492 1493endmenu # lock debugging 1494 1495config TRACE_IRQFLAGS 1496 depends on TRACE_IRQFLAGS_SUPPORT 1497 bool 1498 help 1499 Enables hooks to interrupt enabling and disabling for 1500 either tracing or lock debugging. 1501 1502config TRACE_IRQFLAGS_NMI 1503 def_bool y 1504 depends on TRACE_IRQFLAGS 1505 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1506 1507config DEBUG_IRQFLAGS 1508 bool "Debug IRQ flag manipulation" 1509 help 1510 Enables checks for potentially unsafe enabling or disabling of 1511 interrupts, such as calling raw_local_irq_restore() when interrupts 1512 are enabled. 1513 1514config STACKTRACE 1515 bool "Stack backtrace support" 1516 depends on STACKTRACE_SUPPORT 1517 help 1518 This option causes the kernel to create a /proc/pid/stack for 1519 every process, showing its current stack trace. 1520 It is also used by various kernel debugging features that require 1521 stack trace generation. 1522 1523config WARN_ALL_UNSEEDED_RANDOM 1524 bool "Warn for all uses of unseeded randomness" 1525 default n 1526 help 1527 Some parts of the kernel contain bugs relating to their use of 1528 cryptographically secure random numbers before it's actually possible 1529 to generate those numbers securely. This setting ensures that these 1530 flaws don't go unnoticed, by enabling a message, should this ever 1531 occur. This will allow people with obscure setups to know when things 1532 are going wrong, so that they might contact developers about fixing 1533 it. 1534 1535 Unfortunately, on some models of some architectures getting 1536 a fully seeded CRNG is extremely difficult, and so this can 1537 result in dmesg getting spammed for a surprisingly long 1538 time. This is really bad from a security perspective, and 1539 so architecture maintainers really need to do what they can 1540 to get the CRNG seeded sooner after the system is booted. 1541 However, since users cannot do anything actionable to 1542 address this, by default this option is disabled. 1543 1544 Say Y here if you want to receive warnings for all uses of 1545 unseeded randomness. This will be of use primarily for 1546 those developers interested in improving the security of 1547 Linux kernels running on their architecture (or 1548 subarchitecture). 1549 1550config DEBUG_KOBJECT 1551 bool "kobject debugging" 1552 depends on DEBUG_KERNEL 1553 help 1554 If you say Y here, some extra kobject debugging messages will be sent 1555 to the syslog. 1556 1557config DEBUG_KOBJECT_RELEASE 1558 bool "kobject release debugging" 1559 depends on DEBUG_OBJECTS_TIMERS 1560 help 1561 kobjects are reference counted objects. This means that their 1562 last reference count put is not predictable, and the kobject can 1563 live on past the point at which a driver decides to drop it's 1564 initial reference to the kobject gained on allocation. An 1565 example of this would be a struct device which has just been 1566 unregistered. 1567 1568 However, some buggy drivers assume that after such an operation, 1569 the memory backing the kobject can be immediately freed. This 1570 goes completely against the principles of a refcounted object. 1571 1572 If you say Y here, the kernel will delay the release of kobjects 1573 on the last reference count to improve the visibility of this 1574 kind of kobject release bug. 1575 1576config HAVE_DEBUG_BUGVERBOSE 1577 bool 1578 1579menu "Debug kernel data structures" 1580 1581config DEBUG_LIST 1582 bool "Debug linked list manipulation" 1583 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1584 help 1585 Enable this to turn on extended checks in the linked-list 1586 walking routines. 1587 1588 If unsure, say N. 1589 1590config DEBUG_PLIST 1591 bool "Debug priority linked list manipulation" 1592 depends on DEBUG_KERNEL 1593 help 1594 Enable this to turn on extended checks in the priority-ordered 1595 linked-list (plist) walking routines. This checks the entire 1596 list multiple times during each manipulation. 1597 1598 If unsure, say N. 1599 1600config DEBUG_SG 1601 bool "Debug SG table operations" 1602 depends on DEBUG_KERNEL 1603 help 1604 Enable this to turn on checks on scatter-gather tables. This can 1605 help find problems with drivers that do not properly initialize 1606 their sg tables. 1607 1608 If unsure, say N. 1609 1610config DEBUG_NOTIFIERS 1611 bool "Debug notifier call chains" 1612 depends on DEBUG_KERNEL 1613 help 1614 Enable this to turn on sanity checking for notifier call chains. 1615 This is most useful for kernel developers to make sure that 1616 modules properly unregister themselves from notifier chains. 1617 This is a relatively cheap check but if you care about maximum 1618 performance, say N. 1619 1620config BUG_ON_DATA_CORRUPTION 1621 bool "Trigger a BUG when data corruption is detected" 1622 select DEBUG_LIST 1623 help 1624 Select this option if the kernel should BUG when it encounters 1625 data corruption in kernel memory structures when they get checked 1626 for validity. 1627 1628 If unsure, say N. 1629 1630endmenu 1631 1632config DEBUG_CREDENTIALS 1633 bool "Debug credential management" 1634 depends on DEBUG_KERNEL 1635 help 1636 Enable this to turn on some debug checking for credential 1637 management. The additional code keeps track of the number of 1638 pointers from task_structs to any given cred struct, and checks to 1639 see that this number never exceeds the usage count of the cred 1640 struct. 1641 1642 Furthermore, if SELinux is enabled, this also checks that the 1643 security pointer in the cred struct is never seen to be invalid. 1644 1645 If unsure, say N. 1646 1647source "kernel/rcu/Kconfig.debug" 1648 1649config DEBUG_WQ_FORCE_RR_CPU 1650 bool "Force round-robin CPU selection for unbound work items" 1651 depends on DEBUG_KERNEL 1652 default n 1653 help 1654 Workqueue used to implicitly guarantee that work items queued 1655 without explicit CPU specified are put on the local CPU. This 1656 guarantee is no longer true and while local CPU is still 1657 preferred work items may be put on foreign CPUs. Kernel 1658 parameter "workqueue.debug_force_rr_cpu" is added to force 1659 round-robin CPU selection to flush out usages which depend on the 1660 now broken guarantee. This config option enables the debug 1661 feature by default. When enabled, memory and cache locality will 1662 be impacted. 1663 1664config CPU_HOTPLUG_STATE_CONTROL 1665 bool "Enable CPU hotplug state control" 1666 depends on DEBUG_KERNEL 1667 depends on HOTPLUG_CPU 1668 default n 1669 help 1670 Allows to write steps between "offline" and "online" to the CPUs 1671 sysfs target file so states can be stepped granular. This is a debug 1672 option for now as the hotplug machinery cannot be stopped and 1673 restarted at arbitrary points yet. 1674 1675 Say N if your are unsure. 1676 1677config LATENCYTOP 1678 bool "Latency measuring infrastructure" 1679 depends on DEBUG_KERNEL 1680 depends on STACKTRACE_SUPPORT 1681 depends on PROC_FS 1682 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1683 select KALLSYMS 1684 select KALLSYMS_ALL 1685 select STACKTRACE 1686 select SCHEDSTATS 1687 help 1688 Enable this option if you want to use the LatencyTOP tool 1689 to find out which userspace is blocking on what kernel operations. 1690 1691source "kernel/trace/Kconfig" 1692 1693config PROVIDE_OHCI1394_DMA_INIT 1694 bool "Remote debugging over FireWire early on boot" 1695 depends on PCI && X86 1696 help 1697 If you want to debug problems which hang or crash the kernel early 1698 on boot and the crashing machine has a FireWire port, you can use 1699 this feature to remotely access the memory of the crashed machine 1700 over FireWire. This employs remote DMA as part of the OHCI1394 1701 specification which is now the standard for FireWire controllers. 1702 1703 With remote DMA, you can monitor the printk buffer remotely using 1704 firescope and access all memory below 4GB using fireproxy from gdb. 1705 Even controlling a kernel debugger is possible using remote DMA. 1706 1707 Usage: 1708 1709 If ohci1394_dma=early is used as boot parameter, it will initialize 1710 all OHCI1394 controllers which are found in the PCI config space. 1711 1712 As all changes to the FireWire bus such as enabling and disabling 1713 devices cause a bus reset and thereby disable remote DMA for all 1714 devices, be sure to have the cable plugged and FireWire enabled on 1715 the debugging host before booting the debug target for debugging. 1716 1717 This code (~1k) is freed after boot. By then, the firewire stack 1718 in charge of the OHCI-1394 controllers should be used instead. 1719 1720 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1721 1722source "samples/Kconfig" 1723 1724config ARCH_HAS_DEVMEM_IS_ALLOWED 1725 bool 1726 1727config STRICT_DEVMEM 1728 bool "Filter access to /dev/mem" 1729 depends on MMU && DEVMEM 1730 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1731 default y if PPC || X86 || ARM64 1732 help 1733 If this option is disabled, you allow userspace (root) access to all 1734 of memory, including kernel and userspace memory. Accidental 1735 access to this is obviously disastrous, but specific access can 1736 be used by people debugging the kernel. Note that with PAT support 1737 enabled, even in this case there are restrictions on /dev/mem 1738 use due to the cache aliasing requirements. 1739 1740 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1741 file only allows userspace access to PCI space and the BIOS code and 1742 data regions. This is sufficient for dosemu and X and all common 1743 users of /dev/mem. 1744 1745 If in doubt, say Y. 1746 1747config IO_STRICT_DEVMEM 1748 bool "Filter I/O access to /dev/mem" 1749 depends on STRICT_DEVMEM 1750 help 1751 If this option is disabled, you allow userspace (root) access to all 1752 io-memory regardless of whether a driver is actively using that 1753 range. Accidental access to this is obviously disastrous, but 1754 specific access can be used by people debugging kernel drivers. 1755 1756 If this option is switched on, the /dev/mem file only allows 1757 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1758 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1759 if the driver using a given range cannot be disabled. 1760 1761 If in doubt, say Y. 1762 1763menu "$(SRCARCH) Debugging" 1764 1765source "arch/$(SRCARCH)/Kconfig.debug" 1766 1767endmenu 1768 1769menu "Kernel Testing and Coverage" 1770 1771source "lib/kunit/Kconfig" 1772 1773config NOTIFIER_ERROR_INJECTION 1774 tristate "Notifier error injection" 1775 depends on DEBUG_KERNEL 1776 select DEBUG_FS 1777 help 1778 This option provides the ability to inject artificial errors to 1779 specified notifier chain callbacks. It is useful to test the error 1780 handling of notifier call chain failures. 1781 1782 Say N if unsure. 1783 1784config PM_NOTIFIER_ERROR_INJECT 1785 tristate "PM notifier error injection module" 1786 depends on PM && NOTIFIER_ERROR_INJECTION 1787 default m if PM_DEBUG 1788 help 1789 This option provides the ability to inject artificial errors to 1790 PM notifier chain callbacks. It is controlled through debugfs 1791 interface /sys/kernel/debug/notifier-error-inject/pm 1792 1793 If the notifier call chain should be failed with some events 1794 notified, write the error code to "actions/<notifier event>/error". 1795 1796 Example: Inject PM suspend error (-12 = -ENOMEM) 1797 1798 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1799 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1800 # echo mem > /sys/power/state 1801 bash: echo: write error: Cannot allocate memory 1802 1803 To compile this code as a module, choose M here: the module will 1804 be called pm-notifier-error-inject. 1805 1806 If unsure, say N. 1807 1808config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1809 tristate "OF reconfig notifier error injection module" 1810 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1811 help 1812 This option provides the ability to inject artificial errors to 1813 OF reconfig notifier chain callbacks. It is controlled 1814 through debugfs interface under 1815 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1816 1817 If the notifier call chain should be failed with some events 1818 notified, write the error code to "actions/<notifier event>/error". 1819 1820 To compile this code as a module, choose M here: the module will 1821 be called of-reconfig-notifier-error-inject. 1822 1823 If unsure, say N. 1824 1825config NETDEV_NOTIFIER_ERROR_INJECT 1826 tristate "Netdev notifier error injection module" 1827 depends on NET && NOTIFIER_ERROR_INJECTION 1828 help 1829 This option provides the ability to inject artificial errors to 1830 netdevice notifier chain callbacks. It is controlled through debugfs 1831 interface /sys/kernel/debug/notifier-error-inject/netdev 1832 1833 If the notifier call chain should be failed with some events 1834 notified, write the error code to "actions/<notifier event>/error". 1835 1836 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1837 1838 # cd /sys/kernel/debug/notifier-error-inject/netdev 1839 # echo -22 > actions/NETDEV_CHANGEMTU/error 1840 # ip link set eth0 mtu 1024 1841 RTNETLINK answers: Invalid argument 1842 1843 To compile this code as a module, choose M here: the module will 1844 be called netdev-notifier-error-inject. 1845 1846 If unsure, say N. 1847 1848config FUNCTION_ERROR_INJECTION 1849 def_bool y 1850 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1851 1852config FAULT_INJECTION 1853 bool "Fault-injection framework" 1854 depends on DEBUG_KERNEL 1855 help 1856 Provide fault-injection framework. 1857 For more details, see Documentation/fault-injection/. 1858 1859config FAILSLAB 1860 bool "Fault-injection capability for kmalloc" 1861 depends on FAULT_INJECTION 1862 depends on SLAB || SLUB 1863 help 1864 Provide fault-injection capability for kmalloc. 1865 1866config FAIL_PAGE_ALLOC 1867 bool "Fault-injection capability for alloc_pages()" 1868 depends on FAULT_INJECTION 1869 help 1870 Provide fault-injection capability for alloc_pages(). 1871 1872config FAULT_INJECTION_USERCOPY 1873 bool "Fault injection capability for usercopy functions" 1874 depends on FAULT_INJECTION 1875 help 1876 Provides fault-injection capability to inject failures 1877 in usercopy functions (copy_from_user(), get_user(), ...). 1878 1879config FAIL_MAKE_REQUEST 1880 bool "Fault-injection capability for disk IO" 1881 depends on FAULT_INJECTION && BLOCK 1882 help 1883 Provide fault-injection capability for disk IO. 1884 1885config FAIL_IO_TIMEOUT 1886 bool "Fault-injection capability for faking disk interrupts" 1887 depends on FAULT_INJECTION && BLOCK 1888 help 1889 Provide fault-injection capability on end IO handling. This 1890 will make the block layer "forget" an interrupt as configured, 1891 thus exercising the error handling. 1892 1893 Only works with drivers that use the generic timeout handling, 1894 for others it won't do anything. 1895 1896config FAIL_FUTEX 1897 bool "Fault-injection capability for futexes" 1898 select DEBUG_FS 1899 depends on FAULT_INJECTION && FUTEX 1900 help 1901 Provide fault-injection capability for futexes. 1902 1903config FAULT_INJECTION_DEBUG_FS 1904 bool "Debugfs entries for fault-injection capabilities" 1905 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1906 help 1907 Enable configuration of fault-injection capabilities via debugfs. 1908 1909config FAIL_FUNCTION 1910 bool "Fault-injection capability for functions" 1911 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1912 help 1913 Provide function-based fault-injection capability. 1914 This will allow you to override a specific function with a return 1915 with given return value. As a result, function caller will see 1916 an error value and have to handle it. This is useful to test the 1917 error handling in various subsystems. 1918 1919config FAIL_MMC_REQUEST 1920 bool "Fault-injection capability for MMC IO" 1921 depends on FAULT_INJECTION_DEBUG_FS && MMC 1922 help 1923 Provide fault-injection capability for MMC IO. 1924 This will make the mmc core return data errors. This is 1925 useful to test the error handling in the mmc block device 1926 and to test how the mmc host driver handles retries from 1927 the block device. 1928 1929config FAIL_SUNRPC 1930 bool "Fault-injection capability for SunRPC" 1931 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1932 help 1933 Provide fault-injection capability for SunRPC and 1934 its consumers. 1935 1936config FAULT_INJECTION_STACKTRACE_FILTER 1937 bool "stacktrace filter for fault-injection capabilities" 1938 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1939 depends on !X86_64 1940 select STACKTRACE 1941 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1942 help 1943 Provide stacktrace filter for fault-injection capabilities 1944 1945config ARCH_HAS_KCOV 1946 bool 1947 help 1948 An architecture should select this when it can successfully 1949 build and run with CONFIG_KCOV. This typically requires 1950 disabling instrumentation for some early boot code. 1951 1952config CC_HAS_SANCOV_TRACE_PC 1953 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1954 1955 1956config KCOV 1957 bool "Code coverage for fuzzing" 1958 depends on ARCH_HAS_KCOV 1959 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1960 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 1961 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 1962 select DEBUG_FS 1963 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1964 select OBJTOOL if HAVE_NOINSTR_HACK 1965 help 1966 KCOV exposes kernel code coverage information in a form suitable 1967 for coverage-guided fuzzing (randomized testing). 1968 1969 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1970 different machines and across reboots. If you need stable PC values, 1971 disable RANDOMIZE_BASE. 1972 1973 For more details, see Documentation/dev-tools/kcov.rst. 1974 1975config KCOV_ENABLE_COMPARISONS 1976 bool "Enable comparison operands collection by KCOV" 1977 depends on KCOV 1978 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 1979 help 1980 KCOV also exposes operands of every comparison in the instrumented 1981 code along with operand sizes and PCs of the comparison instructions. 1982 These operands can be used by fuzzing engines to improve the quality 1983 of fuzzing coverage. 1984 1985config KCOV_INSTRUMENT_ALL 1986 bool "Instrument all code by default" 1987 depends on KCOV 1988 default y 1989 help 1990 If you are doing generic system call fuzzing (like e.g. syzkaller), 1991 then you will want to instrument the whole kernel and you should 1992 say y here. If you are doing more targeted fuzzing (like e.g. 1993 filesystem fuzzing with AFL) then you will want to enable coverage 1994 for more specific subsets of files, and should say n here. 1995 1996config KCOV_IRQ_AREA_SIZE 1997 hex "Size of interrupt coverage collection area in words" 1998 depends on KCOV 1999 default 0x40000 2000 help 2001 KCOV uses preallocated per-cpu areas to collect coverage from 2002 soft interrupts. This specifies the size of those areas in the 2003 number of unsigned long words. 2004 2005menuconfig RUNTIME_TESTING_MENU 2006 bool "Runtime Testing" 2007 def_bool y 2008 2009if RUNTIME_TESTING_MENU 2010 2011config LKDTM 2012 tristate "Linux Kernel Dump Test Tool Module" 2013 depends on DEBUG_FS 2014 help 2015 This module enables testing of the different dumping mechanisms by 2016 inducing system failures at predefined crash points. 2017 If you don't need it: say N 2018 Choose M here to compile this code as a module. The module will be 2019 called lkdtm. 2020 2021 Documentation on how to use the module can be found in 2022 Documentation/fault-injection/provoke-crashes.rst 2023 2024config TEST_LIST_SORT 2025 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2026 depends on KUNIT 2027 default KUNIT_ALL_TESTS 2028 help 2029 Enable this to turn on 'list_sort()' function test. This test is 2030 executed only once during system boot (so affects only boot time), 2031 or at module load time. 2032 2033 If unsure, say N. 2034 2035config TEST_MIN_HEAP 2036 tristate "Min heap test" 2037 depends on DEBUG_KERNEL || m 2038 help 2039 Enable this to turn on min heap function tests. This test is 2040 executed only once during system boot (so affects only boot time), 2041 or at module load time. 2042 2043 If unsure, say N. 2044 2045config TEST_SORT 2046 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2047 depends on KUNIT 2048 default KUNIT_ALL_TESTS 2049 help 2050 This option enables the self-test function of 'sort()' at boot, 2051 or at module load time. 2052 2053 If unsure, say N. 2054 2055config TEST_DIV64 2056 tristate "64bit/32bit division and modulo test" 2057 depends on DEBUG_KERNEL || m 2058 help 2059 Enable this to turn on 'do_div()' function test. This test is 2060 executed only once during system boot (so affects only boot time), 2061 or at module load time. 2062 2063 If unsure, say N. 2064 2065config KPROBES_SANITY_TEST 2066 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2067 depends on DEBUG_KERNEL 2068 depends on KPROBES 2069 depends on KUNIT 2070 default KUNIT_ALL_TESTS 2071 help 2072 This option provides for testing basic kprobes functionality on 2073 boot. Samples of kprobe and kretprobe are inserted and 2074 verified for functionality. 2075 2076 Say N if you are unsure. 2077 2078config FPROBE_SANITY_TEST 2079 bool "Self test for fprobe" 2080 depends on DEBUG_KERNEL 2081 depends on FPROBE 2082 depends on KUNIT=y 2083 help 2084 This option will enable testing the fprobe when the system boot. 2085 A series of tests are made to verify that the fprobe is functioning 2086 properly. 2087 2088 Say N if you are unsure. 2089 2090config BACKTRACE_SELF_TEST 2091 tristate "Self test for the backtrace code" 2092 depends on DEBUG_KERNEL 2093 help 2094 This option provides a kernel module that can be used to test 2095 the kernel stack backtrace code. This option is not useful 2096 for distributions or general kernels, but only for kernel 2097 developers working on architecture code. 2098 2099 Note that if you want to also test saved backtraces, you will 2100 have to enable STACKTRACE as well. 2101 2102 Say N if you are unsure. 2103 2104config TEST_REF_TRACKER 2105 tristate "Self test for reference tracker" 2106 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2107 select REF_TRACKER 2108 help 2109 This option provides a kernel module performing tests 2110 using reference tracker infrastructure. 2111 2112 Say N if you are unsure. 2113 2114config RBTREE_TEST 2115 tristate "Red-Black tree test" 2116 depends on DEBUG_KERNEL 2117 help 2118 A benchmark measuring the performance of the rbtree library. 2119 Also includes rbtree invariant checks. 2120 2121config REED_SOLOMON_TEST 2122 tristate "Reed-Solomon library test" 2123 depends on DEBUG_KERNEL || m 2124 select REED_SOLOMON 2125 select REED_SOLOMON_ENC16 2126 select REED_SOLOMON_DEC16 2127 help 2128 This option enables the self-test function of rslib at boot, 2129 or at module load time. 2130 2131 If unsure, say N. 2132 2133config INTERVAL_TREE_TEST 2134 tristate "Interval tree test" 2135 depends on DEBUG_KERNEL 2136 select INTERVAL_TREE 2137 help 2138 A benchmark measuring the performance of the interval tree library 2139 2140config PERCPU_TEST 2141 tristate "Per cpu operations test" 2142 depends on m && DEBUG_KERNEL 2143 help 2144 Enable this option to build test module which validates per-cpu 2145 operations. 2146 2147 If unsure, say N. 2148 2149config ATOMIC64_SELFTEST 2150 tristate "Perform an atomic64_t self-test" 2151 help 2152 Enable this option to test the atomic64_t functions at boot or 2153 at module load time. 2154 2155 If unsure, say N. 2156 2157config ASYNC_RAID6_TEST 2158 tristate "Self test for hardware accelerated raid6 recovery" 2159 depends on ASYNC_RAID6_RECOV 2160 select ASYNC_MEMCPY 2161 help 2162 This is a one-shot self test that permutes through the 2163 recovery of all the possible two disk failure scenarios for a 2164 N-disk array. Recovery is performed with the asynchronous 2165 raid6 recovery routines, and will optionally use an offload 2166 engine if one is available. 2167 2168 If unsure, say N. 2169 2170config TEST_HEXDUMP 2171 tristate "Test functions located in the hexdump module at runtime" 2172 2173config STRING_SELFTEST 2174 tristate "Test string functions at runtime" 2175 2176config TEST_STRING_HELPERS 2177 tristate "Test functions located in the string_helpers module at runtime" 2178 2179config TEST_STRSCPY 2180 tristate "Test strscpy*() family of functions at runtime" 2181 2182config TEST_KSTRTOX 2183 tristate "Test kstrto*() family of functions at runtime" 2184 2185config TEST_PRINTF 2186 tristate "Test printf() family of functions at runtime" 2187 2188config TEST_SCANF 2189 tristate "Test scanf() family of functions at runtime" 2190 2191config TEST_BITMAP 2192 tristate "Test bitmap_*() family of functions at runtime" 2193 help 2194 Enable this option to test the bitmap functions at boot. 2195 2196 If unsure, say N. 2197 2198config TEST_UUID 2199 tristate "Test functions located in the uuid module at runtime" 2200 2201config TEST_XARRAY 2202 tristate "Test the XArray code at runtime" 2203 2204config TEST_RHASHTABLE 2205 tristate "Perform selftest on resizable hash table" 2206 help 2207 Enable this option to test the rhashtable functions at boot. 2208 2209 If unsure, say N. 2210 2211config TEST_SIPHASH 2212 tristate "Perform selftest on siphash functions" 2213 help 2214 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2215 functions on boot (or module load). 2216 2217 This is intended to help people writing architecture-specific 2218 optimized versions. If unsure, say N. 2219 2220config TEST_IDA 2221 tristate "Perform selftest on IDA functions" 2222 2223config TEST_PARMAN 2224 tristate "Perform selftest on priority array manager" 2225 depends on PARMAN 2226 help 2227 Enable this option to test priority array manager on boot 2228 (or module load). 2229 2230 If unsure, say N. 2231 2232config TEST_IRQ_TIMINGS 2233 bool "IRQ timings selftest" 2234 depends on IRQ_TIMINGS 2235 help 2236 Enable this option to test the irq timings code on boot. 2237 2238 If unsure, say N. 2239 2240config TEST_LKM 2241 tristate "Test module loading with 'hello world' module" 2242 depends on m 2243 help 2244 This builds the "test_module" module that emits "Hello, world" 2245 on printk when loaded. It is designed to be used for basic 2246 evaluation of the module loading subsystem (for example when 2247 validating module verification). It lacks any extra dependencies, 2248 and will not normally be loaded by the system unless explicitly 2249 requested by name. 2250 2251 If unsure, say N. 2252 2253config TEST_BITOPS 2254 tristate "Test module for compilation of bitops operations" 2255 depends on m 2256 help 2257 This builds the "test_bitops" module that is much like the 2258 TEST_LKM module except that it does a basic exercise of the 2259 set/clear_bit macros and get_count_order/long to make sure there are 2260 no compiler warnings from C=1 sparse checker or -Wextra 2261 compilations. It has no dependencies and doesn't run or load unless 2262 explicitly requested by name. for example: modprobe test_bitops. 2263 2264 If unsure, say N. 2265 2266config TEST_VMALLOC 2267 tristate "Test module for stress/performance analysis of vmalloc allocator" 2268 default n 2269 depends on MMU 2270 depends on m 2271 help 2272 This builds the "test_vmalloc" module that should be used for 2273 stress and performance analysis. So, any new change for vmalloc 2274 subsystem can be evaluated from performance and stability point 2275 of view. 2276 2277 If unsure, say N. 2278 2279config TEST_USER_COPY 2280 tristate "Test user/kernel boundary protections" 2281 depends on m 2282 help 2283 This builds the "test_user_copy" module that runs sanity checks 2284 on the copy_to/from_user infrastructure, making sure basic 2285 user/kernel boundary testing is working. If it fails to load, 2286 a regression has been detected in the user/kernel memory boundary 2287 protections. 2288 2289 If unsure, say N. 2290 2291config TEST_BPF 2292 tristate "Test BPF filter functionality" 2293 depends on m && NET 2294 help 2295 This builds the "test_bpf" module that runs various test vectors 2296 against the BPF interpreter or BPF JIT compiler depending on the 2297 current setting. This is in particular useful for BPF JIT compiler 2298 development, but also to run regression tests against changes in 2299 the interpreter code. It also enables test stubs for eBPF maps and 2300 verifier used by user space verifier testsuite. 2301 2302 If unsure, say N. 2303 2304config TEST_BLACKHOLE_DEV 2305 tristate "Test blackhole netdev functionality" 2306 depends on m && NET 2307 help 2308 This builds the "test_blackhole_dev" module that validates the 2309 data path through this blackhole netdev. 2310 2311 If unsure, say N. 2312 2313config FIND_BIT_BENCHMARK 2314 tristate "Test find_bit functions" 2315 help 2316 This builds the "test_find_bit" module that measure find_*_bit() 2317 functions performance. 2318 2319 If unsure, say N. 2320 2321config TEST_FIRMWARE 2322 tristate "Test firmware loading via userspace interface" 2323 depends on FW_LOADER 2324 help 2325 This builds the "test_firmware" module that creates a userspace 2326 interface for testing firmware loading. This can be used to 2327 control the triggering of firmware loading without needing an 2328 actual firmware-using device. The contents can be rechecked by 2329 userspace. 2330 2331 If unsure, say N. 2332 2333config TEST_SYSCTL 2334 tristate "sysctl test driver" 2335 depends on PROC_SYSCTL 2336 help 2337 This builds the "test_sysctl" module. This driver enables to test the 2338 proc sysctl interfaces available to drivers safely without affecting 2339 production knobs which might alter system functionality. 2340 2341 If unsure, say N. 2342 2343config BITFIELD_KUNIT 2344 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2345 depends on KUNIT 2346 default KUNIT_ALL_TESTS 2347 help 2348 Enable this option to test the bitfield functions at boot. 2349 2350 KUnit tests run during boot and output the results to the debug log 2351 in TAP format (http://testanything.org/). Only useful for kernel devs 2352 running the KUnit test harness, and not intended for inclusion into a 2353 production build. 2354 2355 For more information on KUnit and unit tests in general please refer 2356 to the KUnit documentation in Documentation/dev-tools/kunit/. 2357 2358 If unsure, say N. 2359 2360config HASH_KUNIT_TEST 2361 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2362 depends on KUNIT 2363 default KUNIT_ALL_TESTS 2364 help 2365 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2366 integer (<linux/hash.h>) hash functions on boot. 2367 2368 KUnit tests run during boot and output the results to the debug log 2369 in TAP format (https://testanything.org/). Only useful for kernel devs 2370 running the KUnit test harness, and not intended for inclusion into a 2371 production build. 2372 2373 For more information on KUnit and unit tests in general please refer 2374 to the KUnit documentation in Documentation/dev-tools/kunit/. 2375 2376 This is intended to help people writing architecture-specific 2377 optimized versions. If unsure, say N. 2378 2379config RESOURCE_KUNIT_TEST 2380 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2381 depends on KUNIT 2382 default KUNIT_ALL_TESTS 2383 help 2384 This builds the resource API unit test. 2385 Tests the logic of API provided by resource.c and ioport.h. 2386 For more information on KUnit and unit tests in general please refer 2387 to the KUnit documentation in Documentation/dev-tools/kunit/. 2388 2389 If unsure, say N. 2390 2391config SYSCTL_KUNIT_TEST 2392 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2393 depends on KUNIT 2394 default KUNIT_ALL_TESTS 2395 help 2396 This builds the proc sysctl unit test, which runs on boot. 2397 Tests the API contract and implementation correctness of sysctl. 2398 For more information on KUnit and unit tests in general please refer 2399 to the KUnit documentation in Documentation/dev-tools/kunit/. 2400 2401 If unsure, say N. 2402 2403config LIST_KUNIT_TEST 2404 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2405 depends on KUNIT 2406 default KUNIT_ALL_TESTS 2407 help 2408 This builds the linked list KUnit test suite. 2409 It tests that the API and basic functionality of the list_head type 2410 and associated macros. 2411 2412 KUnit tests run during boot and output the results to the debug log 2413 in TAP format (https://testanything.org/). Only useful for kernel devs 2414 running the KUnit test harness, and not intended for inclusion into a 2415 production build. 2416 2417 For more information on KUnit and unit tests in general please refer 2418 to the KUnit documentation in Documentation/dev-tools/kunit/. 2419 2420 If unsure, say N. 2421 2422config LINEAR_RANGES_TEST 2423 tristate "KUnit test for linear_ranges" 2424 depends on KUNIT 2425 select LINEAR_RANGES 2426 help 2427 This builds the linear_ranges unit test, which runs on boot. 2428 Tests the linear_ranges logic correctness. 2429 For more information on KUnit and unit tests in general please refer 2430 to the KUnit documentation in Documentation/dev-tools/kunit/. 2431 2432 If unsure, say N. 2433 2434config CMDLINE_KUNIT_TEST 2435 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2436 depends on KUNIT 2437 default KUNIT_ALL_TESTS 2438 help 2439 This builds the cmdline API unit test. 2440 Tests the logic of API provided by cmdline.c. 2441 For more information on KUnit and unit tests in general please refer 2442 to the KUnit documentation in Documentation/dev-tools/kunit/. 2443 2444 If unsure, say N. 2445 2446config BITS_TEST 2447 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2448 depends on KUNIT 2449 default KUNIT_ALL_TESTS 2450 help 2451 This builds the bits unit test. 2452 Tests the logic of macros defined in bits.h. 2453 For more information on KUnit and unit tests in general please refer 2454 to the KUnit documentation in Documentation/dev-tools/kunit/. 2455 2456 If unsure, say N. 2457 2458config SLUB_KUNIT_TEST 2459 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2460 depends on SLUB_DEBUG && KUNIT 2461 default KUNIT_ALL_TESTS 2462 help 2463 This builds SLUB allocator unit test. 2464 Tests SLUB cache debugging functionality. 2465 For more information on KUnit and unit tests in general please refer 2466 to the KUnit documentation in Documentation/dev-tools/kunit/. 2467 2468 If unsure, say N. 2469 2470config RATIONAL_KUNIT_TEST 2471 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2472 depends on KUNIT && RATIONAL 2473 default KUNIT_ALL_TESTS 2474 help 2475 This builds the rational math unit test. 2476 For more information on KUnit and unit tests in general please refer 2477 to the KUnit documentation in Documentation/dev-tools/kunit/. 2478 2479 If unsure, say N. 2480 2481config MEMCPY_KUNIT_TEST 2482 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2483 depends on KUNIT 2484 default KUNIT_ALL_TESTS 2485 help 2486 Builds unit tests for memcpy(), memmove(), and memset() functions. 2487 For more information on KUnit and unit tests in general please refer 2488 to the KUnit documentation in Documentation/dev-tools/kunit/. 2489 2490 If unsure, say N. 2491 2492config OVERFLOW_KUNIT_TEST 2493 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2494 depends on KUNIT 2495 default KUNIT_ALL_TESTS 2496 help 2497 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2498 related functions. 2499 2500 For more information on KUnit and unit tests in general please refer 2501 to the KUnit documentation in Documentation/dev-tools/kunit/. 2502 2503 If unsure, say N. 2504 2505config STACKINIT_KUNIT_TEST 2506 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2507 depends on KUNIT 2508 default KUNIT_ALL_TESTS 2509 help 2510 Test if the kernel is zero-initializing stack variables and 2511 padding. Coverage is controlled by compiler flags, 2512 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2513 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2514 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2515 2516config TEST_UDELAY 2517 tristate "udelay test driver" 2518 help 2519 This builds the "udelay_test" module that helps to make sure 2520 that udelay() is working properly. 2521 2522 If unsure, say N. 2523 2524config TEST_STATIC_KEYS 2525 tristate "Test static keys" 2526 depends on m 2527 help 2528 Test the static key interfaces. 2529 2530 If unsure, say N. 2531 2532config TEST_KMOD 2533 tristate "kmod stress tester" 2534 depends on m 2535 depends on NETDEVICES && NET_CORE && INET # for TUN 2536 depends on BLOCK 2537 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2538 select TEST_LKM 2539 select XFS_FS 2540 select TUN 2541 select BTRFS_FS 2542 help 2543 Test the kernel's module loading mechanism: kmod. kmod implements 2544 support to load modules using the Linux kernel's usermode helper. 2545 This test provides a series of tests against kmod. 2546 2547 Although technically you can either build test_kmod as a module or 2548 into the kernel we disallow building it into the kernel since 2549 it stress tests request_module() and this will very likely cause 2550 some issues by taking over precious threads available from other 2551 module load requests, ultimately this could be fatal. 2552 2553 To run tests run: 2554 2555 tools/testing/selftests/kmod/kmod.sh --help 2556 2557 If unsure, say N. 2558 2559config TEST_DEBUG_VIRTUAL 2560 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2561 depends on DEBUG_VIRTUAL 2562 help 2563 Test the kernel's ability to detect incorrect calls to 2564 virt_to_phys() done against the non-linear part of the 2565 kernel's virtual address map. 2566 2567 If unsure, say N. 2568 2569config TEST_MEMCAT_P 2570 tristate "Test memcat_p() helper function" 2571 help 2572 Test the memcat_p() helper for correctly merging two 2573 pointer arrays together. 2574 2575 If unsure, say N. 2576 2577config TEST_LIVEPATCH 2578 tristate "Test livepatching" 2579 default n 2580 depends on DYNAMIC_DEBUG 2581 depends on LIVEPATCH 2582 depends on m 2583 help 2584 Test kernel livepatching features for correctness. The tests will 2585 load test modules that will be livepatched in various scenarios. 2586 2587 To run all the livepatching tests: 2588 2589 make -C tools/testing/selftests TARGETS=livepatch run_tests 2590 2591 Alternatively, individual tests may be invoked: 2592 2593 tools/testing/selftests/livepatch/test-callbacks.sh 2594 tools/testing/selftests/livepatch/test-livepatch.sh 2595 tools/testing/selftests/livepatch/test-shadow-vars.sh 2596 2597 If unsure, say N. 2598 2599config TEST_OBJAGG 2600 tristate "Perform selftest on object aggreration manager" 2601 default n 2602 depends on OBJAGG 2603 help 2604 Enable this option to test object aggregation manager on boot 2605 (or module load). 2606 2607config TEST_MEMINIT 2608 tristate "Test heap/page initialization" 2609 help 2610 Test if the kernel is zero-initializing heap and page allocations. 2611 This can be useful to test init_on_alloc and init_on_free features. 2612 2613 If unsure, say N. 2614 2615config TEST_HMM 2616 tristate "Test HMM (Heterogeneous Memory Management)" 2617 depends on TRANSPARENT_HUGEPAGE 2618 depends on DEVICE_PRIVATE 2619 select HMM_MIRROR 2620 select MMU_NOTIFIER 2621 help 2622 This is a pseudo device driver solely for testing HMM. 2623 Say M here if you want to build the HMM test module. 2624 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2625 2626 If unsure, say N. 2627 2628config TEST_FREE_PAGES 2629 tristate "Test freeing pages" 2630 help 2631 Test that a memory leak does not occur due to a race between 2632 freeing a block of pages and a speculative page reference. 2633 Loading this module is safe if your kernel has the bug fixed. 2634 If the bug is not fixed, it will leak gigabytes of memory and 2635 probably OOM your system. 2636 2637config TEST_FPU 2638 tristate "Test floating point operations in kernel space" 2639 depends on X86 && !KCOV_INSTRUMENT_ALL 2640 help 2641 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2642 which will trigger a sequence of floating point operations. This is used 2643 for self-testing floating point control register setting in 2644 kernel_fpu_begin(). 2645 2646 If unsure, say N. 2647 2648config TEST_CLOCKSOURCE_WATCHDOG 2649 tristate "Test clocksource watchdog in kernel space" 2650 depends on CLOCKSOURCE_WATCHDOG 2651 help 2652 Enable this option to create a kernel module that will trigger 2653 a test of the clocksource watchdog. This module may be loaded 2654 via modprobe or insmod in which case it will run upon being 2655 loaded, or it may be built in, in which case it will run 2656 shortly after boot. 2657 2658 If unsure, say N. 2659 2660endif # RUNTIME_TESTING_MENU 2661 2662config ARCH_USE_MEMTEST 2663 bool 2664 help 2665 An architecture should select this when it uses early_memtest() 2666 during boot process. 2667 2668config MEMTEST 2669 bool "Memtest" 2670 depends on ARCH_USE_MEMTEST 2671 help 2672 This option adds a kernel parameter 'memtest', which allows memtest 2673 to be set and executed. 2674 memtest=0, mean disabled; -- default 2675 memtest=1, mean do 1 test pattern; 2676 ... 2677 memtest=17, mean do 17 test patterns. 2678 If you are unsure how to answer this question, answer N. 2679 2680 2681 2682config HYPERV_TESTING 2683 bool "Microsoft Hyper-V driver testing" 2684 default n 2685 depends on HYPERV && DEBUG_FS 2686 help 2687 Select this option to enable Hyper-V vmbus testing. 2688 2689endmenu # "Kernel Testing and Coverage" 2690 2691source "Documentation/Kconfig" 2692 2693endmenu # Kernel hacking 2694