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 211menu "Compile-time checks and compiler options" 212 213config DEBUG_INFO 214 bool "Compile the kernel with debug info" 215 depends on DEBUG_KERNEL && !COMPILE_TEST 216 help 217 If you say Y here the resulting kernel image will include 218 debugging info resulting in a larger kernel image. 219 This adds debug symbols to the kernel and modules (gcc -g), and 220 is needed if you intend to use kernel crashdump or binary object 221 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 222 Say Y here only if you plan to debug the kernel. 223 224 If unsure, say N. 225 226if DEBUG_INFO 227 228config DEBUG_INFO_REDUCED 229 bool "Reduce debugging information" 230 help 231 If you say Y here gcc is instructed to generate less debugging 232 information for structure types. This means that tools that 233 need full debugging information (like kgdb or systemtap) won't 234 be happy. But if you merely need debugging information to 235 resolve line numbers there is no loss. Advantage is that 236 build directory object sizes shrink dramatically over a full 237 DEBUG_INFO build and compile times are reduced too. 238 Only works with newer gcc versions. 239 240config DEBUG_INFO_COMPRESSED 241 bool "Compressed debugging information" 242 depends on $(cc-option,-gz=zlib) 243 depends on $(ld-option,--compress-debug-sections=zlib) 244 help 245 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 246 5.0+, binutils 2.26+, and zlib. 247 248 Users of dpkg-deb via scripts/package/builddeb may find an increase in 249 size of their debug .deb packages with this config set, due to the 250 debug info being compressed with zlib, then the object files being 251 recompressed with a different compression scheme. But this is still 252 preferable to setting $KDEB_COMPRESS to "none" which would be even 253 larger. 254 255config DEBUG_INFO_SPLIT 256 bool "Produce split debuginfo in .dwo files" 257 depends on $(cc-option,-gsplit-dwarf) 258 help 259 Generate debug info into separate .dwo files. This significantly 260 reduces the build directory size for builds with DEBUG_INFO, 261 because it stores the information only once on disk in .dwo 262 files instead of multiple times in object files and executables. 263 In addition the debug information is also compressed. 264 265 Requires recent gcc (4.7+) and recent gdb/binutils. 266 Any tool that packages or reads debug information would need 267 to know about the .dwo files and include them. 268 Incompatible with older versions of ccache. 269 270choice 271 prompt "DWARF version" 272 help 273 Which version of DWARF debug info to emit. 274 275config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 276 bool "Rely on the toolchain's implicit default DWARF version" 277 help 278 The implicit default version of DWARF debug info produced by a 279 toolchain changes over time. 280 281 This can break consumers of the debug info that haven't upgraded to 282 support newer revisions, and prevent testing newer versions, but 283 those should be less common scenarios. 284 285 If unsure, say Y. 286 287config DEBUG_INFO_DWARF4 288 bool "Generate DWARF Version 4 debuginfo" 289 help 290 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. 291 292 If you have consumers of DWARF debug info that are not ready for 293 newer revisions of DWARF, you may wish to choose this or have your 294 config select this. 295 296config DEBUG_INFO_DWARF5 297 bool "Generate DWARF Version 5 debuginfo" 298 depends on GCC_VERSION >= 50000 || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) 299 depends on !DEBUG_INFO_BTF 300 help 301 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 302 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 303 draft features until 7.0), and gdb 8.0+. 304 305 Changes to the structure of debug info in Version 5 allow for around 306 15-18% savings in resulting image and debug info section sizes as 307 compared to DWARF Version 4. DWARF Version 5 standardizes previous 308 extensions such as accelerators for symbol indexing and the format 309 for fission (.dwo/.dwp) files. Users may not want to select this 310 config if they rely on tooling that has not yet been updated to 311 support DWARF Version 5. 312 313endchoice # "DWARF version" 314 315config DEBUG_INFO_BTF 316 bool "Generate BTF typeinfo" 317 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 318 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 319 help 320 Generate deduplicated BTF type information from DWARF debug info. 321 Turning this on expects presence of pahole tool, which will convert 322 DWARF type info into equivalent deduplicated BTF type info. 323 324config PAHOLE_HAS_SPLIT_BTF 325 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119") 326 327config DEBUG_INFO_BTF_MODULES 328 def_bool y 329 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 330 help 331 Generate compact split BTF type information for kernel modules. 332 333config GDB_SCRIPTS 334 bool "Provide GDB scripts for kernel debugging" 335 help 336 This creates the required links to GDB helper scripts in the 337 build directory. If you load vmlinux into gdb, the helper 338 scripts will be automatically imported by gdb as well, and 339 additional functions are available to analyze a Linux kernel 340 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 341 for further details. 342 343endif # DEBUG_INFO 344 345config FRAME_WARN 346 int "Warn for stack frames larger than" 347 range 0 8192 348 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 349 default 1280 if (!64BIT && PARISC) 350 default 1024 if (!64BIT && !PARISC) 351 default 2048 if 64BIT 352 help 353 Tell gcc to warn at build time for stack frames larger than this. 354 Setting this too low will cause a lot of warnings. 355 Setting it to 0 disables the warning. 356 357config STRIP_ASM_SYMS 358 bool "Strip assembler-generated symbols during link" 359 default n 360 help 361 Strip internal assembler-generated symbols during a link (symbols 362 that look like '.Lxxx') so they don't pollute the output of 363 get_wchan() and suchlike. 364 365config READABLE_ASM 366 bool "Generate readable assembler code" 367 depends on DEBUG_KERNEL 368 help 369 Disable some compiler optimizations that tend to generate human unreadable 370 assembler output. This may make the kernel slightly slower, but it helps 371 to keep kernel developers who have to stare a lot at assembler listings 372 sane. 373 374config HEADERS_INSTALL 375 bool "Install uapi headers to usr/include" 376 depends on !UML 377 help 378 This option will install uapi headers (headers exported to user-space) 379 into the usr/include directory for use during the kernel build. 380 This is unneeded for building the kernel itself, but needed for some 381 user-space program samples. It is also needed by some features such 382 as uapi header sanity checks. 383 384config DEBUG_SECTION_MISMATCH 385 bool "Enable full Section mismatch analysis" 386 help 387 The section mismatch analysis checks if there are illegal 388 references from one section to another section. 389 During linktime or runtime, some sections are dropped; 390 any use of code/data previously in these sections would 391 most likely result in an oops. 392 In the code, functions and variables are annotated with 393 __init,, etc. (see the full list in include/linux/init.h), 394 which results in the code/data being placed in specific sections. 395 The section mismatch analysis is always performed after a full 396 kernel build, and enabling this option causes the following 397 additional step to occur: 398 - Add the option -fno-inline-functions-called-once to gcc commands. 399 When inlining a function annotated with __init in a non-init 400 function, we would lose the section information and thus 401 the analysis would not catch the illegal reference. 402 This option tells gcc to inline less (but it does result in 403 a larger kernel). 404 405config SECTION_MISMATCH_WARN_ONLY 406 bool "Make section mismatch errors non-fatal" 407 default y 408 help 409 If you say N here, the build process will fail if there are any 410 section mismatch, instead of just throwing warnings. 411 412 If unsure, say Y. 413 414config DEBUG_FORCE_FUNCTION_ALIGN_64B 415 bool "Force all function address 64B aligned" if EXPERT 416 help 417 There are cases that a commit from one domain changes the function 418 address alignment of other domains, and cause magic performance 419 bump (regression or improvement). Enable this option will help to 420 verify if the bump is caused by function alignment changes, while 421 it will slightly increase the kernel size and affect icache usage. 422 423 It is mainly for debug and performance tuning use. 424 425# 426# Select this config option from the architecture Kconfig, if it 427# is preferred to always offer frame pointers as a config 428# option on the architecture (regardless of KERNEL_DEBUG): 429# 430config ARCH_WANT_FRAME_POINTERS 431 bool 432 433config FRAME_POINTER 434 bool "Compile the kernel with frame pointers" 435 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 436 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 437 help 438 If you say Y here the resulting kernel image will be slightly 439 larger and slower, but it gives very useful debugging information 440 in case of kernel bugs. (precise oopses/stacktraces/warnings) 441 442config STACK_VALIDATION 443 bool "Compile-time stack metadata validation" 444 depends on HAVE_STACK_VALIDATION 445 default n 446 help 447 Add compile-time checks to validate stack metadata, including frame 448 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure 449 that runtime stack traces are more reliable. 450 451 This is also a prerequisite for generation of ORC unwind data, which 452 is needed for CONFIG_UNWINDER_ORC. 453 454 For more information, see 455 tools/objtool/Documentation/stack-validation.txt. 456 457config VMLINUX_VALIDATION 458 bool 459 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT 460 default y 461 462config VMLINUX_MAP 463 bool "Generate vmlinux.map file when linking" 464 depends on EXPERT 465 help 466 Selecting this option will pass "-Map=vmlinux.map" to ld 467 when linking vmlinux. That file can be useful for verifying 468 and debugging magic section games, and for seeing which 469 pieces of code get eliminated with 470 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 471 472config DEBUG_FORCE_WEAK_PER_CPU 473 bool "Force weak per-cpu definitions" 474 depends on DEBUG_KERNEL 475 help 476 s390 and alpha require percpu variables in modules to be 477 defined weak to work around addressing range issue which 478 puts the following two restrictions on percpu variable 479 definitions. 480 481 1. percpu symbols must be unique whether static or not 482 2. percpu variables can't be defined inside a function 483 484 To ensure that generic code follows the above rules, this 485 option forces all percpu variables to be defined as weak. 486 487endmenu # "Compiler options" 488 489menu "Generic Kernel Debugging Instruments" 490 491config MAGIC_SYSRQ 492 bool "Magic SysRq key" 493 depends on !UML 494 help 495 If you say Y here, you will have some control over the system even 496 if the system crashes for example during kernel debugging (e.g., you 497 will be able to flush the buffer cache to disk, reboot the system 498 immediately or dump some status information). This is accomplished 499 by pressing various keys while holding SysRq (Alt+PrintScreen). It 500 also works on a serial console (on PC hardware at least), if you 501 send a BREAK and then within 5 seconds a command keypress. The 502 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 503 Don't say Y unless you really know what this hack does. 504 505config MAGIC_SYSRQ_DEFAULT_ENABLE 506 hex "Enable magic SysRq key functions by default" 507 depends on MAGIC_SYSRQ 508 default 0x1 509 help 510 Specifies which SysRq key functions are enabled by default. 511 This may be set to 1 or 0 to enable or disable them all, or 512 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 513 514config MAGIC_SYSRQ_SERIAL 515 bool "Enable magic SysRq key over serial" 516 depends on MAGIC_SYSRQ 517 default y 518 help 519 Many embedded boards have a disconnected TTL level serial which can 520 generate some garbage that can lead to spurious false sysrq detects. 521 This option allows you to decide whether you want to enable the 522 magic SysRq key. 523 524config MAGIC_SYSRQ_SERIAL_SEQUENCE 525 string "Char sequence that enables magic SysRq over serial" 526 depends on MAGIC_SYSRQ_SERIAL 527 default "" 528 help 529 Specifies a sequence of characters that can follow BREAK to enable 530 SysRq on a serial console. 531 532 If unsure, leave an empty string and the option will not be enabled. 533 534config DEBUG_FS 535 bool "Debug Filesystem" 536 help 537 debugfs is a virtual file system that kernel developers use to put 538 debugging files into. Enable this option to be able to read and 539 write to these files. 540 541 For detailed documentation on the debugfs API, see 542 Documentation/filesystems/. 543 544 If unsure, say N. 545 546choice 547 prompt "Debugfs default access" 548 depends on DEBUG_FS 549 default DEBUG_FS_ALLOW_ALL 550 help 551 This selects the default access restrictions for debugfs. 552 It can be overridden with kernel command line option 553 debugfs=[on,no-mount,off]. The restrictions apply for API access 554 and filesystem registration. 555 556config DEBUG_FS_ALLOW_ALL 557 bool "Access normal" 558 help 559 No restrictions apply. Both API and filesystem registration 560 is on. This is the normal default operation. 561 562config DEBUG_FS_DISALLOW_MOUNT 563 bool "Do not register debugfs as filesystem" 564 help 565 The API is open but filesystem is not loaded. Clients can still do 566 their work and read with debug tools that do not need 567 debugfs filesystem. 568 569config DEBUG_FS_ALLOW_NONE 570 bool "No access" 571 help 572 Access is off. Clients get -PERM when trying to create nodes in 573 debugfs tree and debugfs is not registered as a filesystem. 574 Client can then back-off or continue without debugfs access. 575 576endchoice 577 578source "lib/Kconfig.kgdb" 579source "lib/Kconfig.ubsan" 580source "lib/Kconfig.kcsan" 581 582endmenu 583 584config DEBUG_KERNEL 585 bool "Kernel debugging" 586 help 587 Say Y here if you are developing drivers or trying to debug and 588 identify kernel problems. 589 590config DEBUG_MISC 591 bool "Miscellaneous debug code" 592 default DEBUG_KERNEL 593 depends on DEBUG_KERNEL 594 help 595 Say Y here if you need to enable miscellaneous debug code that should 596 be under a more specific debug option but isn't. 597 598 599menu "Memory Debugging" 600 601source "mm/Kconfig.debug" 602 603config DEBUG_OBJECTS 604 bool "Debug object operations" 605 depends on DEBUG_KERNEL 606 help 607 If you say Y here, additional code will be inserted into the 608 kernel to track the life time of various objects and validate 609 the operations on those objects. 610 611config DEBUG_OBJECTS_SELFTEST 612 bool "Debug objects selftest" 613 depends on DEBUG_OBJECTS 614 help 615 This enables the selftest of the object debug code. 616 617config DEBUG_OBJECTS_FREE 618 bool "Debug objects in freed memory" 619 depends on DEBUG_OBJECTS 620 help 621 This enables checks whether a k/v free operation frees an area 622 which contains an object which has not been deactivated 623 properly. This can make kmalloc/kfree-intensive workloads 624 much slower. 625 626config DEBUG_OBJECTS_TIMERS 627 bool "Debug timer objects" 628 depends on DEBUG_OBJECTS 629 help 630 If you say Y here, additional code will be inserted into the 631 timer routines to track the life time of timer objects and 632 validate the timer operations. 633 634config DEBUG_OBJECTS_WORK 635 bool "Debug work objects" 636 depends on DEBUG_OBJECTS 637 help 638 If you say Y here, additional code will be inserted into the 639 work queue routines to track the life time of work objects and 640 validate the work operations. 641 642config DEBUG_OBJECTS_RCU_HEAD 643 bool "Debug RCU callbacks objects" 644 depends on DEBUG_OBJECTS 645 help 646 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 647 648config DEBUG_OBJECTS_PERCPU_COUNTER 649 bool "Debug percpu counter objects" 650 depends on DEBUG_OBJECTS 651 help 652 If you say Y here, additional code will be inserted into the 653 percpu counter routines to track the life time of percpu counter 654 objects and validate the percpu counter operations. 655 656config DEBUG_OBJECTS_ENABLE_DEFAULT 657 int "debug_objects bootup default value (0-1)" 658 range 0 1 659 default "1" 660 depends on DEBUG_OBJECTS 661 help 662 Debug objects boot parameter default value 663 664config DEBUG_SLAB 665 bool "Debug slab memory allocations" 666 depends on DEBUG_KERNEL && SLAB 667 help 668 Say Y here to have the kernel do limited verification on memory 669 allocation as well as poisoning memory on free to catch use of freed 670 memory. This can make kmalloc/kfree-intensive workloads much slower. 671 672config SLUB_DEBUG_ON 673 bool "SLUB debugging on by default" 674 depends on SLUB && SLUB_DEBUG 675 default n 676 help 677 Boot with debugging on by default. SLUB boots by default with 678 the runtime debug capabilities switched off. Enabling this is 679 equivalent to specifying the "slub_debug" parameter on boot. 680 There is no support for more fine grained debug control like 681 possible with slub_debug=xxx. SLUB debugging may be switched 682 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 683 "slub_debug=-". 684 685config SLUB_STATS 686 default n 687 bool "Enable SLUB performance statistics" 688 depends on SLUB && SYSFS 689 help 690 SLUB statistics are useful to debug SLUBs allocation behavior in 691 order find ways to optimize the allocator. This should never be 692 enabled for production use since keeping statistics slows down 693 the allocator by a few percentage points. The slabinfo command 694 supports the determination of the most active slabs to figure 695 out which slabs are relevant to a particular load. 696 Try running: slabinfo -DA 697 698config HAVE_DEBUG_KMEMLEAK 699 bool 700 701config DEBUG_KMEMLEAK 702 bool "Kernel memory leak detector" 703 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 704 select DEBUG_FS 705 select STACKTRACE if STACKTRACE_SUPPORT 706 select KALLSYMS 707 select CRC32 708 help 709 Say Y here if you want to enable the memory leak 710 detector. The memory allocation/freeing is traced in a way 711 similar to the Boehm's conservative garbage collector, the 712 difference being that the orphan objects are not freed but 713 only shown in /sys/kernel/debug/kmemleak. Enabling this 714 feature will introduce an overhead to memory 715 allocations. See Documentation/dev-tools/kmemleak.rst for more 716 details. 717 718 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 719 of finding leaks due to the slab objects poisoning. 720 721 In order to access the kmemleak file, debugfs needs to be 722 mounted (usually at /sys/kernel/debug). 723 724config DEBUG_KMEMLEAK_MEM_POOL_SIZE 725 int "Kmemleak memory pool size" 726 depends on DEBUG_KMEMLEAK 727 range 200 1000000 728 default 16000 729 help 730 Kmemleak must track all the memory allocations to avoid 731 reporting false positives. Since memory may be allocated or 732 freed before kmemleak is fully initialised, use a static pool 733 of metadata objects to track such callbacks. After kmemleak is 734 fully initialised, this memory pool acts as an emergency one 735 if slab allocations fail. 736 737config DEBUG_KMEMLEAK_TEST 738 tristate "Simple test for the kernel memory leak detector" 739 depends on DEBUG_KMEMLEAK && m 740 help 741 This option enables a module that explicitly leaks memory. 742 743 If unsure, say N. 744 745config DEBUG_KMEMLEAK_DEFAULT_OFF 746 bool "Default kmemleak to off" 747 depends on DEBUG_KMEMLEAK 748 help 749 Say Y here to disable kmemleak by default. It can then be enabled 750 on the command line via kmemleak=on. 751 752config DEBUG_KMEMLEAK_AUTO_SCAN 753 bool "Enable kmemleak auto scan thread on boot up" 754 default y 755 depends on DEBUG_KMEMLEAK 756 help 757 Depending on the cpu, kmemleak scan may be cpu intensive and can 758 stall user tasks at times. This option enables/disables automatic 759 kmemleak scan at boot up. 760 761 Say N here to disable kmemleak auto scan thread to stop automatic 762 scanning. Disabling this option disables automatic reporting of 763 memory leaks. 764 765 If unsure, say Y. 766 767config DEBUG_STACK_USAGE 768 bool "Stack utilization instrumentation" 769 depends on DEBUG_KERNEL && !IA64 770 help 771 Enables the display of the minimum amount of free stack which each 772 task has ever had available in the sysrq-T and sysrq-P debug output. 773 774 This option will slow down process creation somewhat. 775 776config SCHED_STACK_END_CHECK 777 bool "Detect stack corruption on calls to schedule()" 778 depends on DEBUG_KERNEL 779 default n 780 help 781 This option checks for a stack overrun on calls to schedule(). 782 If the stack end location is found to be over written always panic as 783 the content of the corrupted region can no longer be trusted. 784 This is to ensure no erroneous behaviour occurs which could result in 785 data corruption or a sporadic crash at a later stage once the region 786 is examined. The runtime overhead introduced is minimal. 787 788config ARCH_HAS_DEBUG_VM_PGTABLE 789 bool 790 help 791 An architecture should select this when it can successfully 792 build and run DEBUG_VM_PGTABLE. 793 794config DEBUG_VM 795 bool "Debug VM" 796 depends on DEBUG_KERNEL 797 help 798 Enable this to turn on extended checks in the virtual-memory system 799 that may impact performance. 800 801 If unsure, say N. 802 803config DEBUG_VM_VMACACHE 804 bool "Debug VMA caching" 805 depends on DEBUG_VM 806 help 807 Enable this to turn on VMA caching debug information. Doing so 808 can cause significant overhead, so only enable it in non-production 809 environments. 810 811 If unsure, say N. 812 813config DEBUG_VM_RB 814 bool "Debug VM red-black trees" 815 depends on DEBUG_VM 816 help 817 Enable VM red-black tree debugging information and extra validations. 818 819 If unsure, say N. 820 821config DEBUG_VM_PGFLAGS 822 bool "Debug page-flags operations" 823 depends on DEBUG_VM 824 help 825 Enables extra validation on page flags operations. 826 827 If unsure, say N. 828 829config DEBUG_VM_PGTABLE 830 bool "Debug arch page table for semantics compliance" 831 depends on MMU 832 depends on ARCH_HAS_DEBUG_VM_PGTABLE 833 default y if DEBUG_VM 834 help 835 This option provides a debug method which can be used to test 836 architecture page table helper functions on various platforms in 837 verifying if they comply with expected generic MM semantics. This 838 will help architecture code in making sure that any changes or 839 new additions of these helpers still conform to expected 840 semantics of the generic MM. Platforms will have to opt in for 841 this through ARCH_HAS_DEBUG_VM_PGTABLE. 842 843 If unsure, say N. 844 845config ARCH_HAS_DEBUG_VIRTUAL 846 bool 847 848config DEBUG_VIRTUAL 849 bool "Debug VM translations" 850 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 851 help 852 Enable some costly sanity checks in virtual to page code. This can 853 catch mistakes with virt_to_page() and friends. 854 855 If unsure, say N. 856 857config DEBUG_NOMMU_REGIONS 858 bool "Debug the global anon/private NOMMU mapping region tree" 859 depends on DEBUG_KERNEL && !MMU 860 help 861 This option causes the global tree of anonymous and private mapping 862 regions to be regularly checked for invalid topology. 863 864config DEBUG_MEMORY_INIT 865 bool "Debug memory initialisation" if EXPERT 866 default !EXPERT 867 help 868 Enable this for additional checks during memory initialisation. 869 The sanity checks verify aspects of the VM such as the memory model 870 and other information provided by the architecture. Verbose 871 information will be printed at KERN_DEBUG loglevel depending 872 on the mminit_loglevel= command-line option. 873 874 If unsure, say Y 875 876config MEMORY_NOTIFIER_ERROR_INJECT 877 tristate "Memory hotplug notifier error injection module" 878 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION 879 help 880 This option provides the ability to inject artificial errors to 881 memory hotplug notifier chain callbacks. It is controlled through 882 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 883 884 If the notifier call chain should be failed with some events 885 notified, write the error code to "actions/<notifier event>/error". 886 887 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 888 889 # cd /sys/kernel/debug/notifier-error-inject/memory 890 # echo -12 > actions/MEM_GOING_OFFLINE/error 891 # echo offline > /sys/devices/system/memory/memoryXXX/state 892 bash: echo: write error: Cannot allocate memory 893 894 To compile this code as a module, choose M here: the module will 895 be called memory-notifier-error-inject. 896 897 If unsure, say N. 898 899config DEBUG_PER_CPU_MAPS 900 bool "Debug access to per_cpu maps" 901 depends on DEBUG_KERNEL 902 depends on SMP 903 help 904 Say Y to verify that the per_cpu map being accessed has 905 been set up. This adds a fair amount of code to kernel memory 906 and decreases performance. 907 908 Say N if unsure. 909 910config DEBUG_KMAP_LOCAL 911 bool "Debug kmap_local temporary mappings" 912 depends on DEBUG_KERNEL && KMAP_LOCAL 913 help 914 This option enables additional error checking for the kmap_local 915 infrastructure. Disable for production use. 916 917config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 918 bool 919 920config DEBUG_KMAP_LOCAL_FORCE_MAP 921 bool "Enforce kmap_local temporary mappings" 922 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 923 select KMAP_LOCAL 924 select DEBUG_KMAP_LOCAL 925 help 926 This option enforces temporary mappings through the kmap_local 927 mechanism for non-highmem pages and on non-highmem systems. 928 Disable this for production systems! 929 930config DEBUG_HIGHMEM 931 bool "Highmem debugging" 932 depends on DEBUG_KERNEL && HIGHMEM 933 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 934 select DEBUG_KMAP_LOCAL 935 help 936 This option enables additional error checking for high memory 937 systems. Disable for production systems. 938 939config HAVE_DEBUG_STACKOVERFLOW 940 bool 941 942config DEBUG_STACKOVERFLOW 943 bool "Check for stack overflows" 944 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 945 help 946 Say Y here if you want to check for overflows of kernel, IRQ 947 and exception stacks (if your architecture uses them). This 948 option will show detailed messages if free stack space drops 949 below a certain limit. 950 951 These kinds of bugs usually occur when call-chains in the 952 kernel get too deep, especially when interrupts are 953 involved. 954 955 Use this in cases where you see apparently random memory 956 corruption, especially if it appears in 'struct thread_info' 957 958 If in doubt, say "N". 959 960source "lib/Kconfig.kasan" 961source "lib/Kconfig.kfence" 962 963endmenu # "Memory Debugging" 964 965config DEBUG_SHIRQ 966 bool "Debug shared IRQ handlers" 967 depends on DEBUG_KERNEL 968 help 969 Enable this to generate a spurious interrupt just before a shared 970 interrupt handler is deregistered (generating one when registering 971 is currently disabled). Drivers need to handle this correctly. Some 972 don't and need to be caught. 973 974menu "Debug Oops, Lockups and Hangs" 975 976config PANIC_ON_OOPS 977 bool "Panic on Oops" 978 help 979 Say Y here to enable the kernel to panic when it oopses. This 980 has the same effect as setting oops=panic on the kernel command 981 line. 982 983 This feature is useful to ensure that the kernel does not do 984 anything erroneous after an oops which could result in data 985 corruption or other issues. 986 987 Say N if unsure. 988 989config PANIC_ON_OOPS_VALUE 990 int 991 range 0 1 992 default 0 if !PANIC_ON_OOPS 993 default 1 if PANIC_ON_OOPS 994 995config PANIC_TIMEOUT 996 int "panic timeout" 997 default 0 998 help 999 Set the timeout value (in seconds) until a reboot occurs when 1000 the kernel panics. If n = 0, then we wait forever. A timeout 1001 value n > 0 will wait n seconds before rebooting, while a timeout 1002 value n < 0 will reboot immediately. 1003 1004config LOCKUP_DETECTOR 1005 bool 1006 1007config SOFTLOCKUP_DETECTOR 1008 bool "Detect Soft Lockups" 1009 depends on DEBUG_KERNEL && !S390 1010 select LOCKUP_DETECTOR 1011 help 1012 Say Y here to enable the kernel to act as a watchdog to detect 1013 soft lockups. 1014 1015 Softlockups are bugs that cause the kernel to loop in kernel 1016 mode for more than 20 seconds, without giving other tasks a 1017 chance to run. The current stack trace is displayed upon 1018 detection and the system will stay locked up. 1019 1020config BOOTPARAM_SOFTLOCKUP_PANIC 1021 bool "Panic (Reboot) On Soft Lockups" 1022 depends on SOFTLOCKUP_DETECTOR 1023 help 1024 Say Y here to enable the kernel to panic on "soft lockups", 1025 which are bugs that cause the kernel to loop in kernel 1026 mode for more than 20 seconds (configurable using the watchdog_thresh 1027 sysctl), without giving other tasks a chance to run. 1028 1029 The panic can be used in combination with panic_timeout, 1030 to cause the system to reboot automatically after a 1031 lockup has been detected. This feature is useful for 1032 high-availability systems that have uptime guarantees and 1033 where a lockup must be resolved ASAP. 1034 1035 Say N if unsure. 1036 1037config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 1038 int 1039 depends on SOFTLOCKUP_DETECTOR 1040 range 0 1 1041 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 1042 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 1043 1044config HARDLOCKUP_DETECTOR_PERF 1045 bool 1046 select SOFTLOCKUP_DETECTOR 1047 1048# 1049# Enables a timestamp based low pass filter to compensate for perf based 1050# hard lockup detection which runs too fast due to turbo modes. 1051# 1052config HARDLOCKUP_CHECK_TIMESTAMP 1053 bool 1054 1055# 1056# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1057# lockup detector rather than the perf based detector. 1058# 1059config HARDLOCKUP_DETECTOR 1060 bool "Detect Hard Lockups" 1061 depends on DEBUG_KERNEL && !S390 1062 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1063 select LOCKUP_DETECTOR 1064 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1065 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH 1066 help 1067 Say Y here to enable the kernel to act as a watchdog to detect 1068 hard lockups. 1069 1070 Hardlockups are bugs that cause the CPU to loop in kernel mode 1071 for more than 10 seconds, without letting other interrupts have a 1072 chance to run. The current stack trace is displayed upon detection 1073 and the system will stay locked up. 1074 1075config BOOTPARAM_HARDLOCKUP_PANIC 1076 bool "Panic (Reboot) On Hard Lockups" 1077 depends on HARDLOCKUP_DETECTOR 1078 help 1079 Say Y here to enable the kernel to panic on "hard lockups", 1080 which are bugs that cause the kernel to loop in kernel 1081 mode with interrupts disabled for more than 10 seconds (configurable 1082 using the watchdog_thresh sysctl). 1083 1084 Say N if unsure. 1085 1086config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1087 int 1088 depends on HARDLOCKUP_DETECTOR 1089 range 0 1 1090 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1091 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1092 1093config DETECT_HUNG_TASK 1094 bool "Detect Hung Tasks" 1095 depends on DEBUG_KERNEL 1096 default SOFTLOCKUP_DETECTOR 1097 help 1098 Say Y here to enable the kernel to detect "hung tasks", 1099 which are bugs that cause the task to be stuck in 1100 uninterruptible "D" state indefinitely. 1101 1102 When a hung task is detected, the kernel will print the 1103 current stack trace (which you should report), but the 1104 task will stay in uninterruptible state. If lockdep is 1105 enabled then all held locks will also be reported. This 1106 feature has negligible overhead. 1107 1108config DEFAULT_HUNG_TASK_TIMEOUT 1109 int "Default timeout for hung task detection (in seconds)" 1110 depends on DETECT_HUNG_TASK 1111 default 120 1112 help 1113 This option controls the default timeout (in seconds) used 1114 to determine when a task has become non-responsive and should 1115 be considered hung. 1116 1117 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1118 sysctl or by writing a value to 1119 /proc/sys/kernel/hung_task_timeout_secs. 1120 1121 A timeout of 0 disables the check. The default is two minutes. 1122 Keeping the default should be fine in most cases. 1123 1124config BOOTPARAM_HUNG_TASK_PANIC 1125 bool "Panic (Reboot) On Hung Tasks" 1126 depends on DETECT_HUNG_TASK 1127 help 1128 Say Y here to enable the kernel to panic on "hung tasks", 1129 which are bugs that cause the kernel to leave a task stuck 1130 in uninterruptible "D" state. 1131 1132 The panic can be used in combination with panic_timeout, 1133 to cause the system to reboot automatically after a 1134 hung task has been detected. This feature is useful for 1135 high-availability systems that have uptime guarantees and 1136 where a hung tasks must be resolved ASAP. 1137 1138 Say N if unsure. 1139 1140config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1141 int 1142 depends on DETECT_HUNG_TASK 1143 range 0 1 1144 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1145 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1146 1147config WQ_WATCHDOG 1148 bool "Detect Workqueue Stalls" 1149 depends on DEBUG_KERNEL 1150 help 1151 Say Y here to enable stall detection on workqueues. If a 1152 worker pool doesn't make forward progress on a pending work 1153 item for over a given amount of time, 30s by default, a 1154 warning message is printed along with dump of workqueue 1155 state. This can be configured through kernel parameter 1156 "workqueue.watchdog_thresh" and its sysfs counterpart. 1157 1158config TEST_LOCKUP 1159 tristate "Test module to generate lockups" 1160 depends on m 1161 help 1162 This builds the "test_lockup" module that helps to make sure 1163 that watchdogs and lockup detectors are working properly. 1164 1165 Depending on module parameters it could emulate soft or hard 1166 lockup, "hung task", or locking arbitrary lock for a long time. 1167 Also it could generate series of lockups with cooling-down periods. 1168 1169 If unsure, say N. 1170 1171endmenu # "Debug lockups and hangs" 1172 1173menu "Scheduler Debugging" 1174 1175config SCHED_DEBUG 1176 bool "Collect scheduler debugging info" 1177 depends on DEBUG_KERNEL && PROC_FS 1178 default y 1179 help 1180 If you say Y here, the /proc/sched_debug file will be provided 1181 that can help debug the scheduler. The runtime overhead of this 1182 option is minimal. 1183 1184config SCHED_INFO 1185 bool 1186 default n 1187 1188config SCHEDSTATS 1189 bool "Collect scheduler statistics" 1190 depends on DEBUG_KERNEL && PROC_FS 1191 select SCHED_INFO 1192 help 1193 If you say Y here, additional code will be inserted into the 1194 scheduler and related routines to collect statistics about 1195 scheduler behavior and provide them in /proc/schedstat. These 1196 stats may be useful for both tuning and debugging the scheduler 1197 If you aren't debugging the scheduler or trying to tune a specific 1198 application, you can say N to avoid the very slight overhead 1199 this adds. 1200 1201endmenu 1202 1203config DEBUG_TIMEKEEPING 1204 bool "Enable extra timekeeping sanity checking" 1205 help 1206 This option will enable additional timekeeping sanity checks 1207 which may be helpful when diagnosing issues where timekeeping 1208 problems are suspected. 1209 1210 This may include checks in the timekeeping hotpaths, so this 1211 option may have a (very small) performance impact to some 1212 workloads. 1213 1214 If unsure, say N. 1215 1216config DEBUG_PREEMPT 1217 bool "Debug preemptible kernel" 1218 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1219 default y 1220 help 1221 If you say Y here then the kernel will use a debug variant of the 1222 commonly used smp_processor_id() function and will print warnings 1223 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1224 will detect preemption count underflows. 1225 1226menu "Lock Debugging (spinlocks, mutexes, etc...)" 1227 1228config LOCK_DEBUGGING_SUPPORT 1229 bool 1230 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1231 default y 1232 1233config PROVE_LOCKING 1234 bool "Lock debugging: prove locking correctness" 1235 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1236 select LOCKDEP 1237 select DEBUG_SPINLOCK 1238 select DEBUG_MUTEXES 1239 select DEBUG_RT_MUTEXES if RT_MUTEXES 1240 select DEBUG_RWSEMS 1241 select DEBUG_WW_MUTEX_SLOWPATH 1242 select DEBUG_LOCK_ALLOC 1243 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1244 select TRACE_IRQFLAGS 1245 default n 1246 help 1247 This feature enables the kernel to prove that all locking 1248 that occurs in the kernel runtime is mathematically 1249 correct: that under no circumstance could an arbitrary (and 1250 not yet triggered) combination of observed locking 1251 sequences (on an arbitrary number of CPUs, running an 1252 arbitrary number of tasks and interrupt contexts) cause a 1253 deadlock. 1254 1255 In short, this feature enables the kernel to report locking 1256 related deadlocks before they actually occur. 1257 1258 The proof does not depend on how hard and complex a 1259 deadlock scenario would be to trigger: how many 1260 participant CPUs, tasks and irq-contexts would be needed 1261 for it to trigger. The proof also does not depend on 1262 timing: if a race and a resulting deadlock is possible 1263 theoretically (no matter how unlikely the race scenario 1264 is), it will be proven so and will immediately be 1265 reported by the kernel (once the event is observed that 1266 makes the deadlock theoretically possible). 1267 1268 If a deadlock is impossible (i.e. the locking rules, as 1269 observed by the kernel, are mathematically correct), the 1270 kernel reports nothing. 1271 1272 NOTE: this feature can also be enabled for rwlocks, mutexes 1273 and rwsems - in which case all dependencies between these 1274 different locking variants are observed and mapped too, and 1275 the proof of observed correctness is also maintained for an 1276 arbitrary combination of these separate locking variants. 1277 1278 For more details, see Documentation/locking/lockdep-design.rst. 1279 1280config PROVE_RAW_LOCK_NESTING 1281 bool "Enable raw_spinlock - spinlock nesting checks" 1282 depends on PROVE_LOCKING 1283 default n 1284 help 1285 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1286 that the lock nesting rules for PREEMPT_RT enabled kernels are 1287 not violated. 1288 1289 NOTE: There are known nesting problems. So if you enable this 1290 option expect lockdep splats until these problems have been fully 1291 addressed which is work in progress. This config switch allows to 1292 identify and analyze these problems. It will be removed and the 1293 check permanently enabled once the main issues have been fixed. 1294 1295 If unsure, select N. 1296 1297config LOCK_STAT 1298 bool "Lock usage statistics" 1299 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1300 select LOCKDEP 1301 select DEBUG_SPINLOCK 1302 select DEBUG_MUTEXES 1303 select DEBUG_RT_MUTEXES if RT_MUTEXES 1304 select DEBUG_LOCK_ALLOC 1305 default n 1306 help 1307 This feature enables tracking lock contention points 1308 1309 For more details, see Documentation/locking/lockstat.rst 1310 1311 This also enables lock events required by "perf lock", 1312 subcommand of perf. 1313 If you want to use "perf lock", you also need to turn on 1314 CONFIG_EVENT_TRACING. 1315 1316 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1317 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1318 1319config DEBUG_RT_MUTEXES 1320 bool "RT Mutex debugging, deadlock detection" 1321 depends on DEBUG_KERNEL && RT_MUTEXES 1322 help 1323 This allows rt mutex semantics violations and rt mutex related 1324 deadlocks (lockups) to be detected and reported automatically. 1325 1326config DEBUG_SPINLOCK 1327 bool "Spinlock and rw-lock debugging: basic checks" 1328 depends on DEBUG_KERNEL 1329 select UNINLINE_SPIN_UNLOCK 1330 help 1331 Say Y here and build SMP to catch missing spinlock initialization 1332 and certain other kinds of spinlock errors commonly made. This is 1333 best used in conjunction with the NMI watchdog so that spinlock 1334 deadlocks are also debuggable. 1335 1336config DEBUG_MUTEXES 1337 bool "Mutex debugging: basic checks" 1338 depends on DEBUG_KERNEL 1339 help 1340 This feature allows mutex semantics violations to be detected and 1341 reported. 1342 1343config DEBUG_WW_MUTEX_SLOWPATH 1344 bool "Wait/wound mutex debugging: Slowpath testing" 1345 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1346 select DEBUG_LOCK_ALLOC 1347 select DEBUG_SPINLOCK 1348 select DEBUG_MUTEXES 1349 help 1350 This feature enables slowpath testing for w/w mutex users by 1351 injecting additional -EDEADLK wound/backoff cases. Together with 1352 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1353 will test all possible w/w mutex interface abuse with the 1354 exception of simply not acquiring all the required locks. 1355 Note that this feature can introduce significant overhead, so 1356 it really should not be enabled in a production or distro kernel, 1357 even a debug kernel. If you are a driver writer, enable it. If 1358 you are a distro, do not. 1359 1360config DEBUG_RWSEMS 1361 bool "RW Semaphore debugging: basic checks" 1362 depends on DEBUG_KERNEL 1363 help 1364 This debugging feature allows mismatched rw semaphore locks 1365 and unlocks to be detected and reported. 1366 1367config DEBUG_LOCK_ALLOC 1368 bool "Lock debugging: detect incorrect freeing of live locks" 1369 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1370 select DEBUG_SPINLOCK 1371 select DEBUG_MUTEXES 1372 select DEBUG_RT_MUTEXES if RT_MUTEXES 1373 select LOCKDEP 1374 help 1375 This feature will check whether any held lock (spinlock, rwlock, 1376 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1377 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1378 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1379 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1380 held during task exit. 1381 1382config LOCKDEP 1383 bool 1384 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1385 select STACKTRACE 1386 select KALLSYMS 1387 select KALLSYMS_ALL 1388 1389config LOCKDEP_SMALL 1390 bool 1391 1392config LOCKDEP_BITS 1393 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1394 depends on LOCKDEP && !LOCKDEP_SMALL 1395 range 10 30 1396 default 15 1397 help 1398 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1399 1400config LOCKDEP_CHAINS_BITS 1401 int "Bitsize for MAX_LOCKDEP_CHAINS" 1402 depends on LOCKDEP && !LOCKDEP_SMALL 1403 range 10 30 1404 default 16 1405 help 1406 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1407 1408config LOCKDEP_STACK_TRACE_BITS 1409 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1410 depends on LOCKDEP && !LOCKDEP_SMALL 1411 range 10 30 1412 default 19 1413 help 1414 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1415 1416config LOCKDEP_STACK_TRACE_HASH_BITS 1417 int "Bitsize for STACK_TRACE_HASH_SIZE" 1418 depends on LOCKDEP && !LOCKDEP_SMALL 1419 range 10 30 1420 default 14 1421 help 1422 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1423 1424config LOCKDEP_CIRCULAR_QUEUE_BITS 1425 int "Bitsize for elements in circular_queue struct" 1426 depends on LOCKDEP 1427 range 10 30 1428 default 12 1429 help 1430 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1431 1432config DEBUG_LOCKDEP 1433 bool "Lock dependency engine debugging" 1434 depends on DEBUG_KERNEL && LOCKDEP 1435 select DEBUG_IRQFLAGS 1436 help 1437 If you say Y here, the lock dependency engine will do 1438 additional runtime checks to debug itself, at the price 1439 of more runtime overhead. 1440 1441config DEBUG_ATOMIC_SLEEP 1442 bool "Sleep inside atomic section checking" 1443 select PREEMPT_COUNT 1444 depends on DEBUG_KERNEL 1445 depends on !ARCH_NO_PREEMPT 1446 help 1447 If you say Y here, various routines which may sleep will become very 1448 noisy if they are called inside atomic sections: when a spinlock is 1449 held, inside an rcu read side critical section, inside preempt disabled 1450 sections, inside an interrupt, etc... 1451 1452config DEBUG_LOCKING_API_SELFTESTS 1453 bool "Locking API boot-time self-tests" 1454 depends on DEBUG_KERNEL 1455 help 1456 Say Y here if you want the kernel to run a short self-test during 1457 bootup. The self-test checks whether common types of locking bugs 1458 are detected by debugging mechanisms or not. (if you disable 1459 lock debugging then those bugs won't be detected of course.) 1460 The following locking APIs are covered: spinlocks, rwlocks, 1461 mutexes and rwsems. 1462 1463config LOCK_TORTURE_TEST 1464 tristate "torture tests for locking" 1465 depends on DEBUG_KERNEL 1466 select TORTURE_TEST 1467 help 1468 This option provides a kernel module that runs torture tests 1469 on kernel locking primitives. The kernel module may be built 1470 after the fact on the running kernel to be tested, if desired. 1471 1472 Say Y here if you want kernel locking-primitive torture tests 1473 to be built into the kernel. 1474 Say M if you want these torture tests to build as a module. 1475 Say N if you are unsure. 1476 1477config WW_MUTEX_SELFTEST 1478 tristate "Wait/wound mutex selftests" 1479 help 1480 This option provides a kernel module that runs tests on the 1481 on the struct ww_mutex locking API. 1482 1483 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1484 with this test harness. 1485 1486 Say M if you want these self tests to build as a module. 1487 Say N if you are unsure. 1488 1489config SCF_TORTURE_TEST 1490 tristate "torture tests for smp_call_function*()" 1491 depends on DEBUG_KERNEL 1492 select TORTURE_TEST 1493 help 1494 This option provides a kernel module that runs torture tests 1495 on the smp_call_function() family of primitives. The kernel 1496 module may be built after the fact on the running kernel to 1497 be tested, if desired. 1498 1499config CSD_LOCK_WAIT_DEBUG 1500 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1501 depends on DEBUG_KERNEL 1502 depends on 64BIT 1503 default n 1504 help 1505 This option enables debug prints when CPUs are slow to respond 1506 to the smp_call_function*() IPI wrappers. These debug prints 1507 include the IPI handler function currently executing (if any) 1508 and relevant stack traces. 1509 1510endmenu # lock debugging 1511 1512config TRACE_IRQFLAGS 1513 depends on TRACE_IRQFLAGS_SUPPORT 1514 bool 1515 help 1516 Enables hooks to interrupt enabling and disabling for 1517 either tracing or lock debugging. 1518 1519config TRACE_IRQFLAGS_NMI 1520 def_bool y 1521 depends on TRACE_IRQFLAGS 1522 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1523 1524config DEBUG_IRQFLAGS 1525 bool "Debug IRQ flag manipulation" 1526 help 1527 Enables checks for potentially unsafe enabling or disabling of 1528 interrupts, such as calling raw_local_irq_restore() when interrupts 1529 are enabled. 1530 1531config STACKTRACE 1532 bool "Stack backtrace support" 1533 depends on STACKTRACE_SUPPORT 1534 help 1535 This option causes the kernel to create a /proc/pid/stack for 1536 every process, showing its current stack trace. 1537 It is also used by various kernel debugging features that require 1538 stack trace generation. 1539 1540config WARN_ALL_UNSEEDED_RANDOM 1541 bool "Warn for all uses of unseeded randomness" 1542 default n 1543 help 1544 Some parts of the kernel contain bugs relating to their use of 1545 cryptographically secure random numbers before it's actually possible 1546 to generate those numbers securely. This setting ensures that these 1547 flaws don't go unnoticed, by enabling a message, should this ever 1548 occur. This will allow people with obscure setups to know when things 1549 are going wrong, so that they might contact developers about fixing 1550 it. 1551 1552 Unfortunately, on some models of some architectures getting 1553 a fully seeded CRNG is extremely difficult, and so this can 1554 result in dmesg getting spammed for a surprisingly long 1555 time. This is really bad from a security perspective, and 1556 so architecture maintainers really need to do what they can 1557 to get the CRNG seeded sooner after the system is booted. 1558 However, since users cannot do anything actionable to 1559 address this, by default the kernel will issue only a single 1560 warning for the first use of unseeded randomness. 1561 1562 Say Y here if you want to receive warnings for all uses of 1563 unseeded randomness. This will be of use primarily for 1564 those developers interested in improving the security of 1565 Linux kernels running on their architecture (or 1566 subarchitecture). 1567 1568config DEBUG_KOBJECT 1569 bool "kobject debugging" 1570 depends on DEBUG_KERNEL 1571 help 1572 If you say Y here, some extra kobject debugging messages will be sent 1573 to the syslog. 1574 1575config DEBUG_KOBJECT_RELEASE 1576 bool "kobject release debugging" 1577 depends on DEBUG_OBJECTS_TIMERS 1578 help 1579 kobjects are reference counted objects. This means that their 1580 last reference count put is not predictable, and the kobject can 1581 live on past the point at which a driver decides to drop it's 1582 initial reference to the kobject gained on allocation. An 1583 example of this would be a struct device which has just been 1584 unregistered. 1585 1586 However, some buggy drivers assume that after such an operation, 1587 the memory backing the kobject can be immediately freed. This 1588 goes completely against the principles of a refcounted object. 1589 1590 If you say Y here, the kernel will delay the release of kobjects 1591 on the last reference count to improve the visibility of this 1592 kind of kobject release bug. 1593 1594config HAVE_DEBUG_BUGVERBOSE 1595 bool 1596 1597menu "Debug kernel data structures" 1598 1599config DEBUG_LIST 1600 bool "Debug linked list manipulation" 1601 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1602 help 1603 Enable this to turn on extended checks in the linked-list 1604 walking routines. 1605 1606 If unsure, say N. 1607 1608config DEBUG_PLIST 1609 bool "Debug priority linked list manipulation" 1610 depends on DEBUG_KERNEL 1611 help 1612 Enable this to turn on extended checks in the priority-ordered 1613 linked-list (plist) walking routines. This checks the entire 1614 list multiple times during each manipulation. 1615 1616 If unsure, say N. 1617 1618config DEBUG_SG 1619 bool "Debug SG table operations" 1620 depends on DEBUG_KERNEL 1621 help 1622 Enable this to turn on checks on scatter-gather tables. This can 1623 help find problems with drivers that do not properly initialize 1624 their sg tables. 1625 1626 If unsure, say N. 1627 1628config DEBUG_NOTIFIERS 1629 bool "Debug notifier call chains" 1630 depends on DEBUG_KERNEL 1631 help 1632 Enable this to turn on sanity checking for notifier call chains. 1633 This is most useful for kernel developers to make sure that 1634 modules properly unregister themselves from notifier chains. 1635 This is a relatively cheap check but if you care about maximum 1636 performance, say N. 1637 1638config BUG_ON_DATA_CORRUPTION 1639 bool "Trigger a BUG when data corruption is detected" 1640 select DEBUG_LIST 1641 help 1642 Select this option if the kernel should BUG when it encounters 1643 data corruption in kernel memory structures when they get checked 1644 for validity. 1645 1646 If unsure, say N. 1647 1648endmenu 1649 1650config DEBUG_CREDENTIALS 1651 bool "Debug credential management" 1652 depends on DEBUG_KERNEL 1653 help 1654 Enable this to turn on some debug checking for credential 1655 management. The additional code keeps track of the number of 1656 pointers from task_structs to any given cred struct, and checks to 1657 see that this number never exceeds the usage count of the cred 1658 struct. 1659 1660 Furthermore, if SELinux is enabled, this also checks that the 1661 security pointer in the cred struct is never seen to be invalid. 1662 1663 If unsure, say N. 1664 1665source "kernel/rcu/Kconfig.debug" 1666 1667config DEBUG_WQ_FORCE_RR_CPU 1668 bool "Force round-robin CPU selection for unbound work items" 1669 depends on DEBUG_KERNEL 1670 default n 1671 help 1672 Workqueue used to implicitly guarantee that work items queued 1673 without explicit CPU specified are put on the local CPU. This 1674 guarantee is no longer true and while local CPU is still 1675 preferred work items may be put on foreign CPUs. Kernel 1676 parameter "workqueue.debug_force_rr_cpu" is added to force 1677 round-robin CPU selection to flush out usages which depend on the 1678 now broken guarantee. This config option enables the debug 1679 feature by default. When enabled, memory and cache locality will 1680 be impacted. 1681 1682config DEBUG_BLOCK_EXT_DEVT 1683 bool "Force extended block device numbers and spread them" 1684 depends on DEBUG_KERNEL 1685 depends on BLOCK 1686 default n 1687 help 1688 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON 1689 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT 1690 YOU ARE DOING. Distros, please enable this and fix whatever 1691 is broken. 1692 1693 Conventionally, block device numbers are allocated from 1694 predetermined contiguous area. However, extended block area 1695 may introduce non-contiguous block device numbers. This 1696 option forces most block device numbers to be allocated from 1697 the extended space and spreads them to discover kernel or 1698 userland code paths which assume predetermined contiguous 1699 device number allocation. 1700 1701 Note that turning on this debug option shuffles all the 1702 device numbers for all IDE and SCSI devices including libata 1703 ones, so root partition specified using device number 1704 directly (via rdev or root=MAJ:MIN) won't work anymore. 1705 Textual device names (root=/dev/sdXn) will continue to work. 1706 1707 Say N if you are unsure. 1708 1709config CPU_HOTPLUG_STATE_CONTROL 1710 bool "Enable CPU hotplug state control" 1711 depends on DEBUG_KERNEL 1712 depends on HOTPLUG_CPU 1713 default n 1714 help 1715 Allows to write steps between "offline" and "online" to the CPUs 1716 sysfs target file so states can be stepped granular. This is a debug 1717 option for now as the hotplug machinery cannot be stopped and 1718 restarted at arbitrary points yet. 1719 1720 Say N if your are unsure. 1721 1722config LATENCYTOP 1723 bool "Latency measuring infrastructure" 1724 depends on DEBUG_KERNEL 1725 depends on STACKTRACE_SUPPORT 1726 depends on PROC_FS 1727 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1728 select KALLSYMS 1729 select KALLSYMS_ALL 1730 select STACKTRACE 1731 select SCHEDSTATS 1732 help 1733 Enable this option if you want to use the LatencyTOP tool 1734 to find out which userspace is blocking on what kernel operations. 1735 1736source "kernel/trace/Kconfig" 1737 1738config PROVIDE_OHCI1394_DMA_INIT 1739 bool "Remote debugging over FireWire early on boot" 1740 depends on PCI && X86 1741 help 1742 If you want to debug problems which hang or crash the kernel early 1743 on boot and the crashing machine has a FireWire port, you can use 1744 this feature to remotely access the memory of the crashed machine 1745 over FireWire. This employs remote DMA as part of the OHCI1394 1746 specification which is now the standard for FireWire controllers. 1747 1748 With remote DMA, you can monitor the printk buffer remotely using 1749 firescope and access all memory below 4GB using fireproxy from gdb. 1750 Even controlling a kernel debugger is possible using remote DMA. 1751 1752 Usage: 1753 1754 If ohci1394_dma=early is used as boot parameter, it will initialize 1755 all OHCI1394 controllers which are found in the PCI config space. 1756 1757 As all changes to the FireWire bus such as enabling and disabling 1758 devices cause a bus reset and thereby disable remote DMA for all 1759 devices, be sure to have the cable plugged and FireWire enabled on 1760 the debugging host before booting the debug target for debugging. 1761 1762 This code (~1k) is freed after boot. By then, the firewire stack 1763 in charge of the OHCI-1394 controllers should be used instead. 1764 1765 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1766 1767source "samples/Kconfig" 1768 1769config ARCH_HAS_DEVMEM_IS_ALLOWED 1770 bool 1771 1772config STRICT_DEVMEM 1773 bool "Filter access to /dev/mem" 1774 depends on MMU && DEVMEM 1775 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1776 default y if PPC || X86 || ARM64 1777 help 1778 If this option is disabled, you allow userspace (root) access to all 1779 of memory, including kernel and userspace memory. Accidental 1780 access to this is obviously disastrous, but specific access can 1781 be used by people debugging the kernel. Note that with PAT support 1782 enabled, even in this case there are restrictions on /dev/mem 1783 use due to the cache aliasing requirements. 1784 1785 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1786 file only allows userspace access to PCI space and the BIOS code and 1787 data regions. This is sufficient for dosemu and X and all common 1788 users of /dev/mem. 1789 1790 If in doubt, say Y. 1791 1792config IO_STRICT_DEVMEM 1793 bool "Filter I/O access to /dev/mem" 1794 depends on STRICT_DEVMEM 1795 help 1796 If this option is disabled, you allow userspace (root) access to all 1797 io-memory regardless of whether a driver is actively using that 1798 range. Accidental access to this is obviously disastrous, but 1799 specific access can be used by people debugging kernel drivers. 1800 1801 If this option is switched on, the /dev/mem file only allows 1802 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1803 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1804 if the driver using a given range cannot be disabled. 1805 1806 If in doubt, say Y. 1807 1808menu "$(SRCARCH) Debugging" 1809 1810source "arch/$(SRCARCH)/Kconfig.debug" 1811 1812endmenu 1813 1814menu "Kernel Testing and Coverage" 1815 1816source "lib/kunit/Kconfig" 1817 1818config NOTIFIER_ERROR_INJECTION 1819 tristate "Notifier error injection" 1820 depends on DEBUG_KERNEL 1821 select DEBUG_FS 1822 help 1823 This option provides the ability to inject artificial errors to 1824 specified notifier chain callbacks. It is useful to test the error 1825 handling of notifier call chain failures. 1826 1827 Say N if unsure. 1828 1829config PM_NOTIFIER_ERROR_INJECT 1830 tristate "PM notifier error injection module" 1831 depends on PM && NOTIFIER_ERROR_INJECTION 1832 default m if PM_DEBUG 1833 help 1834 This option provides the ability to inject artificial errors to 1835 PM notifier chain callbacks. It is controlled through debugfs 1836 interface /sys/kernel/debug/notifier-error-inject/pm 1837 1838 If the notifier call chain should be failed with some events 1839 notified, write the error code to "actions/<notifier event>/error". 1840 1841 Example: Inject PM suspend error (-12 = -ENOMEM) 1842 1843 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1844 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1845 # echo mem > /sys/power/state 1846 bash: echo: write error: Cannot allocate memory 1847 1848 To compile this code as a module, choose M here: the module will 1849 be called pm-notifier-error-inject. 1850 1851 If unsure, say N. 1852 1853config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1854 tristate "OF reconfig notifier error injection module" 1855 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1856 help 1857 This option provides the ability to inject artificial errors to 1858 OF reconfig notifier chain callbacks. It is controlled 1859 through debugfs interface under 1860 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1861 1862 If the notifier call chain should be failed with some events 1863 notified, write the error code to "actions/<notifier event>/error". 1864 1865 To compile this code as a module, choose M here: the module will 1866 be called of-reconfig-notifier-error-inject. 1867 1868 If unsure, say N. 1869 1870config NETDEV_NOTIFIER_ERROR_INJECT 1871 tristate "Netdev notifier error injection module" 1872 depends on NET && NOTIFIER_ERROR_INJECTION 1873 help 1874 This option provides the ability to inject artificial errors to 1875 netdevice notifier chain callbacks. It is controlled through debugfs 1876 interface /sys/kernel/debug/notifier-error-inject/netdev 1877 1878 If the notifier call chain should be failed with some events 1879 notified, write the error code to "actions/<notifier event>/error". 1880 1881 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1882 1883 # cd /sys/kernel/debug/notifier-error-inject/netdev 1884 # echo -22 > actions/NETDEV_CHANGEMTU/error 1885 # ip link set eth0 mtu 1024 1886 RTNETLINK answers: Invalid argument 1887 1888 To compile this code as a module, choose M here: the module will 1889 be called netdev-notifier-error-inject. 1890 1891 If unsure, say N. 1892 1893config FUNCTION_ERROR_INJECTION 1894 def_bool y 1895 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1896 1897config FAULT_INJECTION 1898 bool "Fault-injection framework" 1899 depends on DEBUG_KERNEL 1900 help 1901 Provide fault-injection framework. 1902 For more details, see Documentation/fault-injection/. 1903 1904config FAILSLAB 1905 bool "Fault-injection capability for kmalloc" 1906 depends on FAULT_INJECTION 1907 depends on SLAB || SLUB 1908 help 1909 Provide fault-injection capability for kmalloc. 1910 1911config FAIL_PAGE_ALLOC 1912 bool "Fault-injection capability for alloc_pages()" 1913 depends on FAULT_INJECTION 1914 help 1915 Provide fault-injection capability for alloc_pages(). 1916 1917config FAULT_INJECTION_USERCOPY 1918 bool "Fault injection capability for usercopy functions" 1919 depends on FAULT_INJECTION 1920 help 1921 Provides fault-injection capability to inject failures 1922 in usercopy functions (copy_from_user(), get_user(), ...). 1923 1924config FAIL_MAKE_REQUEST 1925 bool "Fault-injection capability for disk IO" 1926 depends on FAULT_INJECTION && BLOCK 1927 help 1928 Provide fault-injection capability for disk IO. 1929 1930config FAIL_IO_TIMEOUT 1931 bool "Fault-injection capability for faking disk interrupts" 1932 depends on FAULT_INJECTION && BLOCK 1933 help 1934 Provide fault-injection capability on end IO handling. This 1935 will make the block layer "forget" an interrupt as configured, 1936 thus exercising the error handling. 1937 1938 Only works with drivers that use the generic timeout handling, 1939 for others it won't do anything. 1940 1941config FAIL_FUTEX 1942 bool "Fault-injection capability for futexes" 1943 select DEBUG_FS 1944 depends on FAULT_INJECTION && FUTEX 1945 help 1946 Provide fault-injection capability for futexes. 1947 1948config FAULT_INJECTION_DEBUG_FS 1949 bool "Debugfs entries for fault-injection capabilities" 1950 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1951 help 1952 Enable configuration of fault-injection capabilities via debugfs. 1953 1954config FAIL_FUNCTION 1955 bool "Fault-injection capability for functions" 1956 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1957 help 1958 Provide function-based fault-injection capability. 1959 This will allow you to override a specific function with a return 1960 with given return value. As a result, function caller will see 1961 an error value and have to handle it. This is useful to test the 1962 error handling in various subsystems. 1963 1964config FAIL_MMC_REQUEST 1965 bool "Fault-injection capability for MMC IO" 1966 depends on FAULT_INJECTION_DEBUG_FS && MMC 1967 help 1968 Provide fault-injection capability for MMC IO. 1969 This will make the mmc core return data errors. This is 1970 useful to test the error handling in the mmc block device 1971 and to test how the mmc host driver handles retries from 1972 the block device. 1973 1974config FAULT_INJECTION_STACKTRACE_FILTER 1975 bool "stacktrace filter for fault-injection capabilities" 1976 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1977 depends on !X86_64 1978 select STACKTRACE 1979 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1980 help 1981 Provide stacktrace filter for fault-injection capabilities 1982 1983config ARCH_HAS_KCOV 1984 bool 1985 help 1986 An architecture should select this when it can successfully 1987 build and run with CONFIG_KCOV. This typically requires 1988 disabling instrumentation for some early boot code. 1989 1990config CC_HAS_SANCOV_TRACE_PC 1991 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1992 1993 1994config KCOV 1995 bool "Code coverage for fuzzing" 1996 depends on ARCH_HAS_KCOV 1997 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1998 select DEBUG_FS 1999 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2000 help 2001 KCOV exposes kernel code coverage information in a form suitable 2002 for coverage-guided fuzzing (randomized testing). 2003 2004 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2005 different machines and across reboots. If you need stable PC values, 2006 disable RANDOMIZE_BASE. 2007 2008 For more details, see Documentation/dev-tools/kcov.rst. 2009 2010config KCOV_ENABLE_COMPARISONS 2011 bool "Enable comparison operands collection by KCOV" 2012 depends on KCOV 2013 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2014 help 2015 KCOV also exposes operands of every comparison in the instrumented 2016 code along with operand sizes and PCs of the comparison instructions. 2017 These operands can be used by fuzzing engines to improve the quality 2018 of fuzzing coverage. 2019 2020config KCOV_INSTRUMENT_ALL 2021 bool "Instrument all code by default" 2022 depends on KCOV 2023 default y 2024 help 2025 If you are doing generic system call fuzzing (like e.g. syzkaller), 2026 then you will want to instrument the whole kernel and you should 2027 say y here. If you are doing more targeted fuzzing (like e.g. 2028 filesystem fuzzing with AFL) then you will want to enable coverage 2029 for more specific subsets of files, and should say n here. 2030 2031config KCOV_IRQ_AREA_SIZE 2032 hex "Size of interrupt coverage collection area in words" 2033 depends on KCOV 2034 default 0x40000 2035 help 2036 KCOV uses preallocated per-cpu areas to collect coverage from 2037 soft interrupts. This specifies the size of those areas in the 2038 number of unsigned long words. 2039 2040menuconfig RUNTIME_TESTING_MENU 2041 bool "Runtime Testing" 2042 def_bool y 2043 2044if RUNTIME_TESTING_MENU 2045 2046config LKDTM 2047 tristate "Linux Kernel Dump Test Tool Module" 2048 depends on DEBUG_FS 2049 help 2050 This module enables testing of the different dumping mechanisms by 2051 inducing system failures at predefined crash points. 2052 If you don't need it: say N 2053 Choose M here to compile this code as a module. The module will be 2054 called lkdtm. 2055 2056 Documentation on how to use the module can be found in 2057 Documentation/fault-injection/provoke-crashes.rst 2058 2059config TEST_LIST_SORT 2060 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2061 depends on KUNIT 2062 default KUNIT_ALL_TESTS 2063 help 2064 Enable this to turn on 'list_sort()' function test. This test is 2065 executed only once during system boot (so affects only boot time), 2066 or at module load time. 2067 2068 If unsure, say N. 2069 2070config TEST_MIN_HEAP 2071 tristate "Min heap test" 2072 depends on DEBUG_KERNEL || m 2073 help 2074 Enable this to turn on min heap function tests. This test is 2075 executed only once during system boot (so affects only boot time), 2076 or at module load time. 2077 2078 If unsure, say N. 2079 2080config TEST_SORT 2081 tristate "Array-based sort test" 2082 depends on DEBUG_KERNEL || m 2083 help 2084 This option enables the self-test function of 'sort()' at boot, 2085 or at module load time. 2086 2087 If unsure, say N. 2088 2089config TEST_DIV64 2090 tristate "64bit/32bit division and modulo test" 2091 depends on DEBUG_KERNEL || m 2092 help 2093 Enable this to turn on 'do_div()' function test. This test is 2094 executed only once during system boot (so affects only boot time), 2095 or at module load time. 2096 2097 If unsure, say N. 2098 2099config KPROBES_SANITY_TEST 2100 bool "Kprobes sanity tests" 2101 depends on DEBUG_KERNEL 2102 depends on KPROBES 2103 help 2104 This option provides for testing basic kprobes functionality on 2105 boot. Samples of kprobe and kretprobe are inserted and 2106 verified for functionality. 2107 2108 Say N if you are unsure. 2109 2110config BACKTRACE_SELF_TEST 2111 tristate "Self test for the backtrace code" 2112 depends on DEBUG_KERNEL 2113 help 2114 This option provides a kernel module that can be used to test 2115 the kernel stack backtrace code. This option is not useful 2116 for distributions or general kernels, but only for kernel 2117 developers working on architecture code. 2118 2119 Note that if you want to also test saved backtraces, you will 2120 have to enable STACKTRACE as well. 2121 2122 Say N if you are unsure. 2123 2124config RBTREE_TEST 2125 tristate "Red-Black tree test" 2126 depends on DEBUG_KERNEL 2127 help 2128 A benchmark measuring the performance of the rbtree library. 2129 Also includes rbtree invariant checks. 2130 2131config REED_SOLOMON_TEST 2132 tristate "Reed-Solomon library test" 2133 depends on DEBUG_KERNEL || m 2134 select REED_SOLOMON 2135 select REED_SOLOMON_ENC16 2136 select REED_SOLOMON_DEC16 2137 help 2138 This option enables the self-test function of rslib at boot, 2139 or at module load time. 2140 2141 If unsure, say N. 2142 2143config INTERVAL_TREE_TEST 2144 tristate "Interval tree test" 2145 depends on DEBUG_KERNEL 2146 select INTERVAL_TREE 2147 help 2148 A benchmark measuring the performance of the interval tree library 2149 2150config PERCPU_TEST 2151 tristate "Per cpu operations test" 2152 depends on m && DEBUG_KERNEL 2153 help 2154 Enable this option to build test module which validates per-cpu 2155 operations. 2156 2157 If unsure, say N. 2158 2159config ATOMIC64_SELFTEST 2160 tristate "Perform an atomic64_t self-test" 2161 help 2162 Enable this option to test the atomic64_t functions at boot or 2163 at module load time. 2164 2165 If unsure, say N. 2166 2167config ASYNC_RAID6_TEST 2168 tristate "Self test for hardware accelerated raid6 recovery" 2169 depends on ASYNC_RAID6_RECOV 2170 select ASYNC_MEMCPY 2171 help 2172 This is a one-shot self test that permutes through the 2173 recovery of all the possible two disk failure scenarios for a 2174 N-disk array. Recovery is performed with the asynchronous 2175 raid6 recovery routines, and will optionally use an offload 2176 engine if one is available. 2177 2178 If unsure, say N. 2179 2180config TEST_HEXDUMP 2181 tristate "Test functions located in the hexdump module at runtime" 2182 2183config TEST_STRING_HELPERS 2184 tristate "Test functions located in the string_helpers module at runtime" 2185 2186config TEST_STRSCPY 2187 tristate "Test strscpy*() family of functions at runtime" 2188 2189config TEST_KSTRTOX 2190 tristate "Test kstrto*() family of functions at runtime" 2191 2192config TEST_PRINTF 2193 tristate "Test printf() family of functions at runtime" 2194 2195config TEST_SCANF 2196 tristate "Test scanf() family of functions at runtime" 2197 2198config TEST_BITMAP 2199 tristate "Test bitmap_*() family of functions at runtime" 2200 help 2201 Enable this option to test the bitmap functions at boot. 2202 2203 If unsure, say N. 2204 2205config TEST_UUID 2206 tristate "Test functions located in the uuid module at runtime" 2207 2208config TEST_XARRAY 2209 tristate "Test the XArray code at runtime" 2210 2211config TEST_OVERFLOW 2212 tristate "Test check_*_overflow() functions at runtime" 2213 2214config TEST_RHASHTABLE 2215 tristate "Perform selftest on resizable hash table" 2216 help 2217 Enable this option to test the rhashtable functions at boot. 2218 2219 If unsure, say N. 2220 2221config TEST_HASH 2222 tristate "Perform selftest on hash functions" 2223 help 2224 Enable this option to test the kernel's integer (<linux/hash.h>), 2225 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) 2226 hash functions on boot (or module load). 2227 2228 This is intended to help people writing architecture-specific 2229 optimized versions. If unsure, say N. 2230 2231config TEST_IDA 2232 tristate "Perform selftest on IDA functions" 2233 2234config TEST_PARMAN 2235 tristate "Perform selftest on priority array manager" 2236 depends on PARMAN 2237 help 2238 Enable this option to test priority array manager on boot 2239 (or module load). 2240 2241 If unsure, say N. 2242 2243config TEST_IRQ_TIMINGS 2244 bool "IRQ timings selftest" 2245 depends on IRQ_TIMINGS 2246 help 2247 Enable this option to test the irq timings code on boot. 2248 2249 If unsure, say N. 2250 2251config TEST_LKM 2252 tristate "Test module loading with 'hello world' module" 2253 depends on m 2254 help 2255 This builds the "test_module" module that emits "Hello, world" 2256 on printk when loaded. It is designed to be used for basic 2257 evaluation of the module loading subsystem (for example when 2258 validating module verification). It lacks any extra dependencies, 2259 and will not normally be loaded by the system unless explicitly 2260 requested by name. 2261 2262 If unsure, say N. 2263 2264config TEST_BITOPS 2265 tristate "Test module for compilation of bitops operations" 2266 depends on m 2267 help 2268 This builds the "test_bitops" module that is much like the 2269 TEST_LKM module except that it does a basic exercise of the 2270 set/clear_bit macros and get_count_order/long to make sure there are 2271 no compiler warnings from C=1 sparse checker or -Wextra 2272 compilations. It has no dependencies and doesn't run or load unless 2273 explicitly requested by name. for example: modprobe test_bitops. 2274 2275 If unsure, say N. 2276 2277config TEST_VMALLOC 2278 tristate "Test module for stress/performance analysis of vmalloc allocator" 2279 default n 2280 depends on MMU 2281 depends on m 2282 help 2283 This builds the "test_vmalloc" module that should be used for 2284 stress and performance analysis. So, any new change for vmalloc 2285 subsystem can be evaluated from performance and stability point 2286 of view. 2287 2288 If unsure, say N. 2289 2290config TEST_USER_COPY 2291 tristate "Test user/kernel boundary protections" 2292 depends on m 2293 help 2294 This builds the "test_user_copy" module that runs sanity checks 2295 on the copy_to/from_user infrastructure, making sure basic 2296 user/kernel boundary testing is working. If it fails to load, 2297 a regression has been detected in the user/kernel memory boundary 2298 protections. 2299 2300 If unsure, say N. 2301 2302config TEST_BPF 2303 tristate "Test BPF filter functionality" 2304 depends on m && NET 2305 help 2306 This builds the "test_bpf" module that runs various test vectors 2307 against the BPF interpreter or BPF JIT compiler depending on the 2308 current setting. This is in particular useful for BPF JIT compiler 2309 development, but also to run regression tests against changes in 2310 the interpreter code. It also enables test stubs for eBPF maps and 2311 verifier used by user space verifier testsuite. 2312 2313 If unsure, say N. 2314 2315config TEST_BLACKHOLE_DEV 2316 tristate "Test blackhole netdev functionality" 2317 depends on m && NET 2318 help 2319 This builds the "test_blackhole_dev" module that validates the 2320 data path through this blackhole netdev. 2321 2322 If unsure, say N. 2323 2324config FIND_BIT_BENCHMARK 2325 tristate "Test find_bit functions" 2326 help 2327 This builds the "test_find_bit" module that measure find_*_bit() 2328 functions performance. 2329 2330 If unsure, say N. 2331 2332config TEST_FIRMWARE 2333 tristate "Test firmware loading via userspace interface" 2334 depends on FW_LOADER 2335 help 2336 This builds the "test_firmware" module that creates a userspace 2337 interface for testing firmware loading. This can be used to 2338 control the triggering of firmware loading without needing an 2339 actual firmware-using device. The contents can be rechecked by 2340 userspace. 2341 2342 If unsure, say N. 2343 2344config TEST_SYSCTL 2345 tristate "sysctl test driver" 2346 depends on PROC_SYSCTL 2347 help 2348 This builds the "test_sysctl" module. This driver enables to test the 2349 proc sysctl interfaces available to drivers safely without affecting 2350 production knobs which might alter system functionality. 2351 2352 If unsure, say N. 2353 2354config BITFIELD_KUNIT 2355 tristate "KUnit test bitfield functions at runtime" 2356 depends on KUNIT 2357 help 2358 Enable this option to test the bitfield functions at boot. 2359 2360 KUnit tests run during boot and output the results to the debug log 2361 in TAP format (http://testanything.org/). Only useful for kernel devs 2362 running the KUnit test harness, and not intended for inclusion into a 2363 production build. 2364 2365 For more information on KUnit and unit tests in general please refer 2366 to the KUnit documentation in Documentation/dev-tools/kunit/. 2367 2368 If unsure, say N. 2369 2370config RESOURCE_KUNIT_TEST 2371 tristate "KUnit test for resource API" 2372 depends on KUNIT 2373 help 2374 This builds the resource API unit test. 2375 Tests the logic of API provided by resource.c and ioport.h. 2376 For more information on KUnit and unit tests in general please refer 2377 to the KUnit documentation in Documentation/dev-tools/kunit/. 2378 2379 If unsure, say N. 2380 2381config SYSCTL_KUNIT_TEST 2382 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2383 depends on KUNIT 2384 default KUNIT_ALL_TESTS 2385 help 2386 This builds the proc sysctl unit test, which runs on boot. 2387 Tests the API contract and implementation correctness of sysctl. 2388 For more information on KUnit and unit tests in general please refer 2389 to the KUnit documentation in Documentation/dev-tools/kunit/. 2390 2391 If unsure, say N. 2392 2393config LIST_KUNIT_TEST 2394 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2395 depends on KUNIT 2396 default KUNIT_ALL_TESTS 2397 help 2398 This builds the linked list KUnit test suite. 2399 It tests that the API and basic functionality of the list_head type 2400 and associated macros. 2401 2402 KUnit tests run during boot and output the results to the debug log 2403 in TAP format (https://testanything.org/). Only useful for kernel devs 2404 running the KUnit test harness, and not intended for inclusion into a 2405 production build. 2406 2407 For more information on KUnit and unit tests in general please refer 2408 to the KUnit documentation in Documentation/dev-tools/kunit/. 2409 2410 If unsure, say N. 2411 2412config LINEAR_RANGES_TEST 2413 tristate "KUnit test for linear_ranges" 2414 depends on KUNIT 2415 select LINEAR_RANGES 2416 help 2417 This builds the linear_ranges unit test, which runs on boot. 2418 Tests the linear_ranges logic correctness. 2419 For more information on KUnit and unit tests in general please refer 2420 to the KUnit documentation in Documentation/dev-tools/kunit/. 2421 2422 If unsure, say N. 2423 2424config CMDLINE_KUNIT_TEST 2425 tristate "KUnit test for cmdline API" 2426 depends on KUNIT 2427 help 2428 This builds the cmdline API unit test. 2429 Tests the logic of API provided by cmdline.c. 2430 For more information on KUnit and unit tests in general please refer 2431 to the KUnit documentation in Documentation/dev-tools/kunit/. 2432 2433 If unsure, say N. 2434 2435config BITS_TEST 2436 tristate "KUnit test for bits.h" 2437 depends on KUNIT 2438 help 2439 This builds the bits unit test. 2440 Tests the logic of macros defined in bits.h. 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 SLUB_KUNIT_TEST 2447 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2448 depends on SLUB_DEBUG && KUNIT 2449 default KUNIT_ALL_TESTS 2450 help 2451 This builds SLUB allocator unit test. 2452 Tests SLUB cache debugging functionality. 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 RATIONAL_KUNIT_TEST 2459 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2460 depends on KUNIT 2461 select RATIONAL 2462 default KUNIT_ALL_TESTS 2463 help 2464 This builds the rational math unit test. 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 TEST_UDELAY 2471 tristate "udelay test driver" 2472 help 2473 This builds the "udelay_test" module that helps to make sure 2474 that udelay() is working properly. 2475 2476 If unsure, say N. 2477 2478config TEST_STATIC_KEYS 2479 tristate "Test static keys" 2480 depends on m 2481 help 2482 Test the static key interfaces. 2483 2484 If unsure, say N. 2485 2486config TEST_KMOD 2487 tristate "kmod stress tester" 2488 depends on m 2489 depends on NETDEVICES && NET_CORE && INET # for TUN 2490 depends on BLOCK 2491 select TEST_LKM 2492 select XFS_FS 2493 select TUN 2494 select BTRFS_FS 2495 help 2496 Test the kernel's module loading mechanism: kmod. kmod implements 2497 support to load modules using the Linux kernel's usermode helper. 2498 This test provides a series of tests against kmod. 2499 2500 Although technically you can either build test_kmod as a module or 2501 into the kernel we disallow building it into the kernel since 2502 it stress tests request_module() and this will very likely cause 2503 some issues by taking over precious threads available from other 2504 module load requests, ultimately this could be fatal. 2505 2506 To run tests run: 2507 2508 tools/testing/selftests/kmod/kmod.sh --help 2509 2510 If unsure, say N. 2511 2512config TEST_DEBUG_VIRTUAL 2513 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2514 depends on DEBUG_VIRTUAL 2515 help 2516 Test the kernel's ability to detect incorrect calls to 2517 virt_to_phys() done against the non-linear part of the 2518 kernel's virtual address map. 2519 2520 If unsure, say N. 2521 2522config TEST_MEMCAT_P 2523 tristate "Test memcat_p() helper function" 2524 help 2525 Test the memcat_p() helper for correctly merging two 2526 pointer arrays together. 2527 2528 If unsure, say N. 2529 2530config TEST_LIVEPATCH 2531 tristate "Test livepatching" 2532 default n 2533 depends on DYNAMIC_DEBUG 2534 depends on LIVEPATCH 2535 depends on m 2536 help 2537 Test kernel livepatching features for correctness. The tests will 2538 load test modules that will be livepatched in various scenarios. 2539 2540 To run all the livepatching tests: 2541 2542 make -C tools/testing/selftests TARGETS=livepatch run_tests 2543 2544 Alternatively, individual tests may be invoked: 2545 2546 tools/testing/selftests/livepatch/test-callbacks.sh 2547 tools/testing/selftests/livepatch/test-livepatch.sh 2548 tools/testing/selftests/livepatch/test-shadow-vars.sh 2549 2550 If unsure, say N. 2551 2552config TEST_OBJAGG 2553 tristate "Perform selftest on object aggreration manager" 2554 default n 2555 depends on OBJAGG 2556 help 2557 Enable this option to test object aggregation manager on boot 2558 (or module load). 2559 2560 2561config TEST_STACKINIT 2562 tristate "Test level of stack variable initialization" 2563 help 2564 Test if the kernel is zero-initializing stack variables and 2565 padding. Coverage is controlled by compiler flags, 2566 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2567 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2568 2569 If unsure, say N. 2570 2571config TEST_MEMINIT 2572 tristate "Test heap/page initialization" 2573 help 2574 Test if the kernel is zero-initializing heap and page allocations. 2575 This can be useful to test init_on_alloc and init_on_free features. 2576 2577 If unsure, say N. 2578 2579config TEST_HMM 2580 tristate "Test HMM (Heterogeneous Memory Management)" 2581 depends on TRANSPARENT_HUGEPAGE 2582 depends on DEVICE_PRIVATE 2583 select HMM_MIRROR 2584 select MMU_NOTIFIER 2585 help 2586 This is a pseudo device driver solely for testing HMM. 2587 Say M here if you want to build the HMM test module. 2588 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2589 2590 If unsure, say N. 2591 2592config TEST_FREE_PAGES 2593 tristate "Test freeing pages" 2594 help 2595 Test that a memory leak does not occur due to a race between 2596 freeing a block of pages and a speculative page reference. 2597 Loading this module is safe if your kernel has the bug fixed. 2598 If the bug is not fixed, it will leak gigabytes of memory and 2599 probably OOM your system. 2600 2601config TEST_FPU 2602 tristate "Test floating point operations in kernel space" 2603 depends on X86 && !KCOV_INSTRUMENT_ALL 2604 help 2605 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2606 which will trigger a sequence of floating point operations. This is used 2607 for self-testing floating point control register setting in 2608 kernel_fpu_begin(). 2609 2610 If unsure, say N. 2611 2612config TEST_CLOCKSOURCE_WATCHDOG 2613 tristate "Test clocksource watchdog in kernel space" 2614 depends on CLOCKSOURCE_WATCHDOG 2615 help 2616 Enable this option to create a kernel module that will trigger 2617 a test of the clocksource watchdog. This module may be loaded 2618 via modprobe or insmod in which case it will run upon being 2619 loaded, or it may be built in, in which case it will run 2620 shortly after boot. 2621 2622 If unsure, say N. 2623 2624endif # RUNTIME_TESTING_MENU 2625 2626config ARCH_USE_MEMTEST 2627 bool 2628 help 2629 An architecture should select this when it uses early_memtest() 2630 during boot process. 2631 2632config MEMTEST 2633 bool "Memtest" 2634 depends on ARCH_USE_MEMTEST 2635 help 2636 This option adds a kernel parameter 'memtest', which allows memtest 2637 to be set and executed. 2638 memtest=0, mean disabled; -- default 2639 memtest=1, mean do 1 test pattern; 2640 ... 2641 memtest=17, mean do 17 test patterns. 2642 If you are unsure how to answer this question, answer N. 2643 2644 2645 2646config HYPERV_TESTING 2647 bool "Microsoft Hyper-V driver testing" 2648 default n 2649 depends on HYPERV && DEBUG_FS 2650 help 2651 Select this option to enable Hyper-V vmbus testing. 2652 2653endmenu # "Kernel Testing and Coverage" 2654 2655source "Documentation/Kconfig" 2656 2657endmenu # Kernel hacking 2658