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