1# SPDX-License-Identifier: GPL-2.0-only 2menu "Kernel hacking" 3 4menu "printk and dmesg options" 5 6config PRINTK_TIME 7 bool "Show timing information on printks" 8 depends on PRINTK 9 help 10 Selecting this option causes time stamps of the printk() 11 messages to be added to the output of the syslog() system 12 call and at the console. 13 14 The timestamp is always recorded internally, and exported 15 to /dev/kmsg. This flag just specifies if the timestamp should 16 be included, not that the timestamp is recorded. 17 18 The behavior is also controlled by the kernel command line 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst 20 21config PRINTK_CALLER 22 bool "Show caller information on printks" 23 depends on PRINTK 24 help 25 Selecting this option causes printk() to add a caller "thread id" (if 26 in task context) or a caller "processor id" (if not in task context) 27 to every message. 28 29 This option is intended for environments where multiple threads 30 concurrently call printk() for many times, for it is difficult to 31 interpret without knowing where these lines (or sometimes individual 32 line which was divided into multiple lines due to race) came from. 33 34 Since toggling after boot makes the code racy, currently there is 35 no option to enable/disable at the kernel command line parameter or 36 sysfs interface. 37 38config STACKTRACE_BUILD_ID 39 bool "Show build ID information in stacktraces" 40 depends on PRINTK 41 help 42 Selecting this option adds build ID information for symbols in 43 stacktraces printed with the printk format '%p[SR]b'. 44 45 This option is intended for distros where debuginfo is not easily 46 accessible but can be downloaded given the build ID of the vmlinux or 47 kernel module where the function is located. 48 49config CONSOLE_LOGLEVEL_DEFAULT 50 int "Default console loglevel (1-15)" 51 range 1 15 52 default "7" 53 help 54 Default loglevel to determine what will be printed on the console. 55 56 Setting a default here is equivalent to passing in loglevel=<x> in 57 the kernel bootargs. loglevel=<x> continues to override whatever 58 value is specified here as well. 59 60 Note: This does not affect the log level of un-prefixed printk() 61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT 62 option. 63 64config CONSOLE_LOGLEVEL_QUIET 65 int "quiet console loglevel (1-15)" 66 range 1 15 67 default "4" 68 help 69 loglevel to use when "quiet" is passed on the kernel commandline. 70 71 When "quiet" is passed on the kernel commandline this loglevel 72 will be used as the loglevel. IOW passing "quiet" will be the 73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" 74 75config MESSAGE_LOGLEVEL_DEFAULT 76 int "Default message log level (1-7)" 77 range 1 7 78 default "4" 79 help 80 Default log level for printk statements with no specified priority. 81 82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks 83 that are auditing their logs closely may want to set it to a lower 84 priority. 85 86 Note: This does not affect what message level gets printed on the console 87 by default. To change that, use loglevel=<x> in the kernel bootargs, 88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. 89 90config BOOT_PRINTK_DELAY 91 bool "Delay each boot printk message by N milliseconds" 92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY 93 help 94 This build option allows you to read kernel boot messages 95 by inserting a short delay after each one. The delay is 96 specified in milliseconds on the kernel command line, 97 using "boot_delay=N". 98 99 It is likely that you would also need to use "lpj=M" to preset 100 the "loops per jiffie" value. 101 See a previous boot log for the "lpj" value to use for your 102 system, and then set "lpj=M" before setting "boot_delay=N". 103 NOTE: Using this option may adversely affect SMP systems. 104 I.e., processors other than the first one may not boot up. 105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect 106 what it believes to be lockup conditions. 107 108config DYNAMIC_DEBUG 109 bool "Enable dynamic printk() support" 110 default n 111 depends on PRINTK 112 depends on (DEBUG_FS || PROC_FS) 113 select DYNAMIC_DEBUG_CORE 114 help 115 116 Compiles debug level messages into the kernel, which would not 117 otherwise be available at runtime. These messages can then be 118 enabled/disabled based on various levels of scope - per source file, 119 function, module, format string, and line number. This mechanism 120 implicitly compiles in all pr_debug() and dev_dbg() calls, which 121 enlarges the kernel text size by about 2%. 122 123 If a source file is compiled with DEBUG flag set, any 124 pr_debug() calls in it are enabled by default, but can be 125 disabled at runtime as below. Note that DEBUG flag is 126 turned on by many CONFIG_*DEBUG* options. 127 128 Usage: 129 130 Dynamic debugging is controlled via the 'dynamic_debug/control' file, 131 which is contained in the 'debugfs' filesystem or procfs. 132 Thus, the debugfs or procfs filesystem must first be mounted before 133 making use of this feature. 134 We refer the control file as: <debugfs>/dynamic_debug/control. This 135 file contains a list of the debug statements that can be enabled. The 136 format for each line of the file is: 137 138 filename:lineno [module]function flags format 139 140 filename : source file of the debug statement 141 lineno : line number of the debug statement 142 module : module that contains the debug statement 143 function : function that contains the debug statement 144 flags : '=p' means the line is turned 'on' for printing 145 format : the format used for the debug statement 146 147 From a live system: 148 149 nullarbor:~ # cat <debugfs>/dynamic_debug/control 150 # filename:lineno [module]function flags format 151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" 152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" 153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" 154 155 Example usage: 156 157 // enable the message at line 1603 of file svcsock.c 158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > 159 <debugfs>/dynamic_debug/control 160 161 // enable all the messages in file svcsock.c 162 nullarbor:~ # echo -n 'file svcsock.c +p' > 163 <debugfs>/dynamic_debug/control 164 165 // enable all the messages in the NFS server module 166 nullarbor:~ # echo -n 'module nfsd +p' > 167 <debugfs>/dynamic_debug/control 168 169 // enable all 12 messages in the function svc_process() 170 nullarbor:~ # echo -n 'func svc_process +p' > 171 <debugfs>/dynamic_debug/control 172 173 // disable all 12 messages in the function svc_process() 174 nullarbor:~ # echo -n 'func svc_process -p' > 175 <debugfs>/dynamic_debug/control 176 177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional 178 information. 179 180config DYNAMIC_DEBUG_CORE 181 bool "Enable core function of dynamic debug support" 182 depends on PRINTK 183 depends on (DEBUG_FS || PROC_FS) 184 help 185 Enable core functional support of dynamic debug. It is useful 186 when you want to tie dynamic debug to your kernel modules with 187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for 188 the case of embedded system where the kernel image size is 189 sensitive for people. 190 191config SYMBOLIC_ERRNAME 192 bool "Support symbolic error names in printf" 193 default y if PRINTK 194 help 195 If you say Y here, the kernel's printf implementation will 196 be able to print symbolic error names such as ENOSPC instead 197 of the number 28. It makes the kernel image slightly larger 198 (about 3KB), but can make the kernel logs easier to read. 199 200config DEBUG_BUGVERBOSE 201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT 202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) 203 default y 204 help 205 Say Y here to make BUG() panics output the file name and line number 206 of the BUG call as well as the EIP and oops trace. This aids 207 debugging but costs about 70-100K of memory. 208 209endmenu # "printk and dmesg options" 210 211config DEBUG_KERNEL 212 bool "Kernel debugging" 213 help 214 Say Y here if you are developing drivers or trying to debug and 215 identify kernel problems. 216 217config DEBUG_MISC 218 bool "Miscellaneous debug code" 219 default DEBUG_KERNEL 220 depends on DEBUG_KERNEL 221 help 222 Say Y here if you need to enable miscellaneous debug code that should 223 be under a more specific debug option but isn't. 224 225menu "Compile-time checks and compiler options" 226 227config DEBUG_INFO 228 bool 229 help 230 A kernel debug info option other than "None" has been selected 231 in the "Debug information" choice below, indicating that debug 232 information will be generated for build targets. 233 234# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which 235# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215 236config AS_HAS_NON_CONST_LEB128 237 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:) 238 239choice 240 prompt "Debug information" 241 depends on DEBUG_KERNEL 242 help 243 Selecting something other than "None" results in a kernel image 244 that will include debugging info resulting in a larger kernel image. 245 This adds debug symbols to the kernel and modules (gcc -g), and 246 is needed if you intend to use kernel crashdump or binary object 247 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 248 249 Choose which version of DWARF debug info to emit. If unsure, 250 select "Toolchain default". 251 252config DEBUG_INFO_NONE 253 bool "Disable debug information" 254 help 255 Do not build the kernel with debugging information, which will 256 result in a faster and smaller build. 257 258config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 259 bool "Rely on the toolchain's implicit default DWARF version" 260 select DEBUG_INFO 261 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) 262 help 263 The implicit default version of DWARF debug info produced by a 264 toolchain changes over time. 265 266 This can break consumers of the debug info that haven't upgraded to 267 support newer revisions, and prevent testing newer versions, but 268 those should be less common scenarios. 269 270config DEBUG_INFO_DWARF4 271 bool "Generate DWARF Version 4 debuginfo" 272 select DEBUG_INFO 273 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502) 274 help 275 Generate DWARF v4 debug info. This requires gcc 4.5+, binutils 2.35.2 276 if using clang without clang's integrated assembler, and gdb 7.0+. 277 278 If you have consumers of DWARF debug info that are not ready for 279 newer revisions of DWARF, you may wish to choose this or have your 280 config select this. 281 282config DEBUG_INFO_DWARF5 283 bool "Generate DWARF Version 5 debuginfo" 284 select DEBUG_INFO 285 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128) 286 help 287 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 288 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 289 draft features until 7.0), and gdb 8.0+. 290 291 Changes to the structure of debug info in Version 5 allow for around 292 15-18% savings in resulting image and debug info section sizes as 293 compared to DWARF Version 4. DWARF Version 5 standardizes previous 294 extensions such as accelerators for symbol indexing and the format 295 for fission (.dwo/.dwp) files. Users may not want to select this 296 config if they rely on tooling that has not yet been updated to 297 support DWARF Version 5. 298 299endchoice # "Debug information" 300 301if DEBUG_INFO 302 303config DEBUG_INFO_REDUCED 304 bool "Reduce debugging information" 305 help 306 If you say Y here gcc is instructed to generate less debugging 307 information for structure types. This means that tools that 308 need full debugging information (like kgdb or systemtap) won't 309 be happy. But if you merely need debugging information to 310 resolve line numbers there is no loss. Advantage is that 311 build directory object sizes shrink dramatically over a full 312 DEBUG_INFO build and compile times are reduced too. 313 Only works with newer gcc versions. 314 315config DEBUG_INFO_COMPRESSED 316 bool "Compressed debugging information" 317 depends on $(cc-option,-gz=zlib) 318 depends on $(ld-option,--compress-debug-sections=zlib) 319 help 320 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 321 5.0+, binutils 2.26+, and zlib. 322 323 Users of dpkg-deb via scripts/package/builddeb may find an increase in 324 size of their debug .deb packages with this config set, due to the 325 debug info being compressed with zlib, then the object files being 326 recompressed with a different compression scheme. But this is still 327 preferable to setting $KDEB_COMPRESS to "none" which would be even 328 larger. 329 330config DEBUG_INFO_SPLIT 331 bool "Produce split debuginfo in .dwo files" 332 depends on $(cc-option,-gsplit-dwarf) 333 help 334 Generate debug info into separate .dwo files. This significantly 335 reduces the build directory size for builds with DEBUG_INFO, 336 because it stores the information only once on disk in .dwo 337 files instead of multiple times in object files and executables. 338 In addition the debug information is also compressed. 339 340 Requires recent gcc (4.7+) and recent gdb/binutils. 341 Any tool that packages or reads debug information would need 342 to know about the .dwo files and include them. 343 Incompatible with older versions of ccache. 344 345config DEBUG_INFO_BTF 346 bool "Generate BTF typeinfo" 347 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 348 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 349 depends on BPF_SYSCALL 350 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 351 help 352 Generate deduplicated BTF type information from DWARF debug info. 353 Turning this on expects presence of pahole tool, which will convert 354 DWARF type info into equivalent deduplicated BTF type info. 355 356config PAHOLE_HAS_SPLIT_BTF 357 def_bool PAHOLE_VERSION >= 119 358 359config PAHOLE_HAS_BTF_TAG 360 def_bool PAHOLE_VERSION >= 123 361 depends on CC_IS_CLANG 362 help 363 Decide whether pahole emits btf_tag attributes (btf_type_tag and 364 btf_decl_tag) or not. Currently only clang compiler implements 365 these attributes, so make the config depend on CC_IS_CLANG. 366 367config DEBUG_INFO_BTF_MODULES 368 def_bool y 369 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 370 help 371 Generate compact split BTF type information for kernel modules. 372 373config MODULE_ALLOW_BTF_MISMATCH 374 bool "Allow loading modules with non-matching BTF type info" 375 depends on DEBUG_INFO_BTF_MODULES 376 help 377 For modules whose split BTF does not match vmlinux, load without 378 BTF rather than refusing to load. The default behavior with 379 module BTF enabled is to reject modules with such mismatches; 380 this option will still load module BTF where possible but ignore 381 it when a mismatch is found. 382 383config GDB_SCRIPTS 384 bool "Provide GDB scripts for kernel debugging" 385 help 386 This creates the required links to GDB helper scripts in the 387 build directory. If you load vmlinux into gdb, the helper 388 scripts will be automatically imported by gdb as well, and 389 additional functions are available to analyze a Linux kernel 390 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 391 for further details. 392 393endif # DEBUG_INFO 394 395config FRAME_WARN 396 int "Warn for stack frames larger than" 397 range 0 8192 398 default 0 if KMSAN 399 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 400 default 2048 if PARISC 401 default 1536 if (!64BIT && XTENSA) 402 default 1280 if KASAN && !64BIT 403 default 1024 if !64BIT 404 default 2048 if 64BIT 405 help 406 Tell the compiler to warn at build time for stack frames larger than this. 407 Setting this too low will cause a lot of warnings. 408 Setting it to 0 disables the warning. 409 410config STRIP_ASM_SYMS 411 bool "Strip assembler-generated symbols during link" 412 default n 413 help 414 Strip internal assembler-generated symbols during a link (symbols 415 that look like '.Lxxx') so they don't pollute the output of 416 get_wchan() and suchlike. 417 418config READABLE_ASM 419 bool "Generate readable assembler code" 420 depends on DEBUG_KERNEL 421 depends on CC_IS_GCC 422 help 423 Disable some compiler optimizations that tend to generate human unreadable 424 assembler output. This may make the kernel slightly slower, but it helps 425 to keep kernel developers who have to stare a lot at assembler listings 426 sane. 427 428config HEADERS_INSTALL 429 bool "Install uapi headers to usr/include" 430 depends on !UML 431 help 432 This option will install uapi headers (headers exported to user-space) 433 into the usr/include directory for use during the kernel build. 434 This is unneeded for building the kernel itself, but needed for some 435 user-space program samples. It is also needed by some features such 436 as uapi header sanity checks. 437 438config DEBUG_SECTION_MISMATCH 439 bool "Enable full Section mismatch analysis" 440 depends on CC_IS_GCC 441 help 442 The section mismatch analysis checks if there are illegal 443 references from one section to another section. 444 During linktime or runtime, some sections are dropped; 445 any use of code/data previously in these sections would 446 most likely result in an oops. 447 In the code, functions and variables are annotated with 448 __init,, etc. (see the full list in include/linux/init.h), 449 which results in the code/data being placed in specific sections. 450 The section mismatch analysis is always performed after a full 451 kernel build, and enabling this option causes the following 452 additional step to occur: 453 - Add the option -fno-inline-functions-called-once to gcc commands. 454 When inlining a function annotated with __init in a non-init 455 function, we would lose the section information and thus 456 the analysis would not catch the illegal reference. 457 This option tells gcc to inline less (but it does result in 458 a larger kernel). 459 460config SECTION_MISMATCH_WARN_ONLY 461 bool "Make section mismatch errors non-fatal" 462 default y 463 help 464 If you say N here, the build process will fail if there are any 465 section mismatch, instead of just throwing warnings. 466 467 If unsure, say Y. 468 469config DEBUG_FORCE_FUNCTION_ALIGN_64B 470 bool "Force all function address 64B aligned" 471 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 472 help 473 There are cases that a commit from one domain changes the function 474 address alignment of other domains, and cause magic performance 475 bump (regression or improvement). Enable this option will help to 476 verify if the bump is caused by function alignment changes, while 477 it will slightly increase the kernel size and affect icache usage. 478 479 It is mainly for debug and performance tuning use. 480 481# 482# Select this config option from the architecture Kconfig, if it 483# is preferred to always offer frame pointers as a config 484# option on the architecture (regardless of KERNEL_DEBUG): 485# 486config ARCH_WANT_FRAME_POINTERS 487 bool 488 489config FRAME_POINTER 490 bool "Compile the kernel with frame pointers" 491 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 492 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 493 help 494 If you say Y here the resulting kernel image will be slightly 495 larger and slower, but it gives very useful debugging information 496 in case of kernel bugs. (precise oopses/stacktraces/warnings) 497 498config OBJTOOL 499 bool 500 501config STACK_VALIDATION 502 bool "Compile-time stack metadata validation" 503 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 504 select OBJTOOL 505 default n 506 help 507 Validate frame pointer rules at compile-time. This helps ensure that 508 runtime stack traces are more reliable. 509 510 For more information, see 511 tools/objtool/Documentation/objtool.txt. 512 513config NOINSTR_VALIDATION 514 bool 515 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 516 select OBJTOOL 517 default y 518 519config VMLINUX_MAP 520 bool "Generate vmlinux.map file when linking" 521 depends on EXPERT 522 help 523 Selecting this option will pass "-Map=vmlinux.map" to ld 524 when linking vmlinux. That file can be useful for verifying 525 and debugging magic section games, and for seeing which 526 pieces of code get eliminated with 527 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 528 529config DEBUG_FORCE_WEAK_PER_CPU 530 bool "Force weak per-cpu definitions" 531 depends on DEBUG_KERNEL 532 help 533 s390 and alpha require percpu variables in modules to be 534 defined weak to work around addressing range issue which 535 puts the following two restrictions on percpu variable 536 definitions. 537 538 1. percpu symbols must be unique whether static or not 539 2. percpu variables can't be defined inside a function 540 541 To ensure that generic code follows the above rules, this 542 option forces all percpu variables to be defined as weak. 543 544endmenu # "Compiler options" 545 546menu "Generic Kernel Debugging Instruments" 547 548config MAGIC_SYSRQ 549 bool "Magic SysRq key" 550 depends on !UML 551 help 552 If you say Y here, you will have some control over the system even 553 if the system crashes for example during kernel debugging (e.g., you 554 will be able to flush the buffer cache to disk, reboot the system 555 immediately or dump some status information). This is accomplished 556 by pressing various keys while holding SysRq (Alt+PrintScreen). It 557 also works on a serial console (on PC hardware at least), if you 558 send a BREAK and then within 5 seconds a command keypress. The 559 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 560 Don't say Y unless you really know what this hack does. 561 562config MAGIC_SYSRQ_DEFAULT_ENABLE 563 hex "Enable magic SysRq key functions by default" 564 depends on MAGIC_SYSRQ 565 default 0x1 566 help 567 Specifies which SysRq key functions are enabled by default. 568 This may be set to 1 or 0 to enable or disable them all, or 569 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 570 571config MAGIC_SYSRQ_SERIAL 572 bool "Enable magic SysRq key over serial" 573 depends on MAGIC_SYSRQ 574 default y 575 help 576 Many embedded boards have a disconnected TTL level serial which can 577 generate some garbage that can lead to spurious false sysrq detects. 578 This option allows you to decide whether you want to enable the 579 magic SysRq key. 580 581config MAGIC_SYSRQ_SERIAL_SEQUENCE 582 string "Char sequence that enables magic SysRq over serial" 583 depends on MAGIC_SYSRQ_SERIAL 584 default "" 585 help 586 Specifies a sequence of characters that can follow BREAK to enable 587 SysRq on a serial console. 588 589 If unsure, leave an empty string and the option will not be enabled. 590 591config DEBUG_FS 592 bool "Debug Filesystem" 593 help 594 debugfs is a virtual file system that kernel developers use to put 595 debugging files into. Enable this option to be able to read and 596 write to these files. 597 598 For detailed documentation on the debugfs API, see 599 Documentation/filesystems/. 600 601 If unsure, say N. 602 603choice 604 prompt "Debugfs default access" 605 depends on DEBUG_FS 606 default DEBUG_FS_ALLOW_ALL 607 help 608 This selects the default access restrictions for debugfs. 609 It can be overridden with kernel command line option 610 debugfs=[on,no-mount,off]. The restrictions apply for API access 611 and filesystem registration. 612 613config DEBUG_FS_ALLOW_ALL 614 bool "Access normal" 615 help 616 No restrictions apply. Both API and filesystem registration 617 is on. This is the normal default operation. 618 619config DEBUG_FS_DISALLOW_MOUNT 620 bool "Do not register debugfs as filesystem" 621 help 622 The API is open but filesystem is not loaded. Clients can still do 623 their work and read with debug tools that do not need 624 debugfs filesystem. 625 626config DEBUG_FS_ALLOW_NONE 627 bool "No access" 628 help 629 Access is off. Clients get -PERM when trying to create nodes in 630 debugfs tree and debugfs is not registered as a filesystem. 631 Client can then back-off or continue without debugfs access. 632 633endchoice 634 635source "lib/Kconfig.kgdb" 636source "lib/Kconfig.ubsan" 637source "lib/Kconfig.kcsan" 638 639endmenu 640 641menu "Networking Debugging" 642 643source "net/Kconfig.debug" 644 645endmenu # "Networking Debugging" 646 647menu "Memory Debugging" 648 649source "mm/Kconfig.debug" 650 651config DEBUG_OBJECTS 652 bool "Debug object operations" 653 depends on DEBUG_KERNEL 654 help 655 If you say Y here, additional code will be inserted into the 656 kernel to track the life time of various objects and validate 657 the operations on those objects. 658 659config DEBUG_OBJECTS_SELFTEST 660 bool "Debug objects selftest" 661 depends on DEBUG_OBJECTS 662 help 663 This enables the selftest of the object debug code. 664 665config DEBUG_OBJECTS_FREE 666 bool "Debug objects in freed memory" 667 depends on DEBUG_OBJECTS 668 help 669 This enables checks whether a k/v free operation frees an area 670 which contains an object which has not been deactivated 671 properly. This can make kmalloc/kfree-intensive workloads 672 much slower. 673 674config DEBUG_OBJECTS_TIMERS 675 bool "Debug timer objects" 676 depends on DEBUG_OBJECTS 677 help 678 If you say Y here, additional code will be inserted into the 679 timer routines to track the life time of timer objects and 680 validate the timer operations. 681 682config DEBUG_OBJECTS_WORK 683 bool "Debug work objects" 684 depends on DEBUG_OBJECTS 685 help 686 If you say Y here, additional code will be inserted into the 687 work queue routines to track the life time of work objects and 688 validate the work operations. 689 690config DEBUG_OBJECTS_RCU_HEAD 691 bool "Debug RCU callbacks objects" 692 depends on DEBUG_OBJECTS 693 help 694 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 695 696config DEBUG_OBJECTS_PERCPU_COUNTER 697 bool "Debug percpu counter objects" 698 depends on DEBUG_OBJECTS 699 help 700 If you say Y here, additional code will be inserted into the 701 percpu counter routines to track the life time of percpu counter 702 objects and validate the percpu counter operations. 703 704config DEBUG_OBJECTS_ENABLE_DEFAULT 705 int "debug_objects bootup default value (0-1)" 706 range 0 1 707 default "1" 708 depends on DEBUG_OBJECTS 709 help 710 Debug objects boot parameter default value 711 712config SHRINKER_DEBUG 713 bool "Enable shrinker debugging support" 714 depends on DEBUG_FS 715 help 716 Say Y to enable the shrinker debugfs interface which provides 717 visibility into the kernel memory shrinkers subsystem. 718 Disable it to avoid an extra memory footprint. 719 720config HAVE_DEBUG_KMEMLEAK 721 bool 722 723config DEBUG_KMEMLEAK 724 bool "Kernel memory leak detector" 725 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 726 select DEBUG_FS 727 select STACKTRACE if STACKTRACE_SUPPORT 728 select KALLSYMS 729 select CRC32 730 help 731 Say Y here if you want to enable the memory leak 732 detector. The memory allocation/freeing is traced in a way 733 similar to the Boehm's conservative garbage collector, the 734 difference being that the orphan objects are not freed but 735 only shown in /sys/kernel/debug/kmemleak. Enabling this 736 feature will introduce an overhead to memory 737 allocations. See Documentation/dev-tools/kmemleak.rst for more 738 details. 739 740 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 741 of finding leaks due to the slab objects poisoning. 742 743 In order to access the kmemleak file, debugfs needs to be 744 mounted (usually at /sys/kernel/debug). 745 746config DEBUG_KMEMLEAK_MEM_POOL_SIZE 747 int "Kmemleak memory pool size" 748 depends on DEBUG_KMEMLEAK 749 range 200 1000000 750 default 16000 751 help 752 Kmemleak must track all the memory allocations to avoid 753 reporting false positives. Since memory may be allocated or 754 freed before kmemleak is fully initialised, use a static pool 755 of metadata objects to track such callbacks. After kmemleak is 756 fully initialised, this memory pool acts as an emergency one 757 if slab allocations fail. 758 759config DEBUG_KMEMLEAK_TEST 760 tristate "Simple test for the kernel memory leak detector" 761 depends on DEBUG_KMEMLEAK && m 762 help 763 This option enables a module that explicitly leaks memory. 764 765 If unsure, say N. 766 767config DEBUG_KMEMLEAK_DEFAULT_OFF 768 bool "Default kmemleak to off" 769 depends on DEBUG_KMEMLEAK 770 help 771 Say Y here to disable kmemleak by default. It can then be enabled 772 on the command line via kmemleak=on. 773 774config DEBUG_KMEMLEAK_AUTO_SCAN 775 bool "Enable kmemleak auto scan thread on boot up" 776 default y 777 depends on DEBUG_KMEMLEAK 778 help 779 Depending on the cpu, kmemleak scan may be cpu intensive and can 780 stall user tasks at times. This option enables/disables automatic 781 kmemleak scan at boot up. 782 783 Say N here to disable kmemleak auto scan thread to stop automatic 784 scanning. Disabling this option disables automatic reporting of 785 memory leaks. 786 787 If unsure, say Y. 788 789config DEBUG_STACK_USAGE 790 bool "Stack utilization instrumentation" 791 depends on DEBUG_KERNEL && !IA64 792 help 793 Enables the display of the minimum amount of free stack which each 794 task has ever had available in the sysrq-T and sysrq-P debug output. 795 796 This option will slow down process creation somewhat. 797 798config SCHED_STACK_END_CHECK 799 bool "Detect stack corruption on calls to schedule()" 800 depends on DEBUG_KERNEL 801 default n 802 help 803 This option checks for a stack overrun on calls to schedule(). 804 If the stack end location is found to be over written always panic as 805 the content of the corrupted region can no longer be trusted. 806 This is to ensure no erroneous behaviour occurs which could result in 807 data corruption or a sporadic crash at a later stage once the region 808 is examined. The runtime overhead introduced is minimal. 809 810config ARCH_HAS_DEBUG_VM_PGTABLE 811 bool 812 help 813 An architecture should select this when it can successfully 814 build and run DEBUG_VM_PGTABLE. 815 816config DEBUG_VM_IRQSOFF 817 def_bool DEBUG_VM && !PREEMPT_RT 818 819config DEBUG_VM 820 bool "Debug VM" 821 depends on DEBUG_KERNEL 822 help 823 Enable this to turn on extended checks in the virtual-memory system 824 that may impact performance. 825 826 If unsure, say N. 827 828config DEBUG_VM_MAPLE_TREE 829 bool "Debug VM maple trees" 830 depends on DEBUG_VM 831 select DEBUG_MAPLE_TREE 832 help 833 Enable VM maple tree debugging information and extra validations. 834 835 If unsure, say N. 836 837config DEBUG_VM_RB 838 bool "Debug VM red-black trees" 839 depends on DEBUG_VM 840 help 841 Enable VM red-black tree debugging information and extra validations. 842 843 If unsure, say N. 844 845config DEBUG_VM_PGFLAGS 846 bool "Debug page-flags operations" 847 depends on DEBUG_VM 848 help 849 Enables extra validation on page flags operations. 850 851 If unsure, say N. 852 853config DEBUG_VM_PGTABLE 854 bool "Debug arch page table for semantics compliance" 855 depends on MMU 856 depends on ARCH_HAS_DEBUG_VM_PGTABLE 857 default y if DEBUG_VM 858 help 859 This option provides a debug method which can be used to test 860 architecture page table helper functions on various platforms in 861 verifying if they comply with expected generic MM semantics. This 862 will help architecture code in making sure that any changes or 863 new additions of these helpers still conform to expected 864 semantics of the generic MM. Platforms will have to opt in for 865 this through ARCH_HAS_DEBUG_VM_PGTABLE. 866 867 If unsure, say N. 868 869config ARCH_HAS_DEBUG_VIRTUAL 870 bool 871 872config DEBUG_VIRTUAL 873 bool "Debug VM translations" 874 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 875 help 876 Enable some costly sanity checks in virtual to page code. This can 877 catch mistakes with virt_to_page() and friends. 878 879 If unsure, say N. 880 881config DEBUG_NOMMU_REGIONS 882 bool "Debug the global anon/private NOMMU mapping region tree" 883 depends on DEBUG_KERNEL && !MMU 884 help 885 This option causes the global tree of anonymous and private mapping 886 regions to be regularly checked for invalid topology. 887 888config DEBUG_MEMORY_INIT 889 bool "Debug memory initialisation" if EXPERT 890 default !EXPERT 891 help 892 Enable this for additional checks during memory initialisation. 893 The sanity checks verify aspects of the VM such as the memory model 894 and other information provided by the architecture. Verbose 895 information will be printed at KERN_DEBUG loglevel depending 896 on the mminit_loglevel= command-line option. 897 898 If unsure, say Y 899 900config MEMORY_NOTIFIER_ERROR_INJECT 901 tristate "Memory hotplug notifier error injection module" 902 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 903 help 904 This option provides the ability to inject artificial errors to 905 memory hotplug notifier chain callbacks. It is controlled through 906 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 907 908 If the notifier call chain should be failed with some events 909 notified, write the error code to "actions/<notifier event>/error". 910 911 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 912 913 # cd /sys/kernel/debug/notifier-error-inject/memory 914 # echo -12 > actions/MEM_GOING_OFFLINE/error 915 # echo offline > /sys/devices/system/memory/memoryXXX/state 916 bash: echo: write error: Cannot allocate memory 917 918 To compile this code as a module, choose M here: the module will 919 be called memory-notifier-error-inject. 920 921 If unsure, say N. 922 923config DEBUG_PER_CPU_MAPS 924 bool "Debug access to per_cpu maps" 925 depends on DEBUG_KERNEL 926 depends on SMP 927 help 928 Say Y to verify that the per_cpu map being accessed has 929 been set up. This adds a fair amount of code to kernel memory 930 and decreases performance. 931 932 Say N if unsure. 933 934config DEBUG_KMAP_LOCAL 935 bool "Debug kmap_local temporary mappings" 936 depends on DEBUG_KERNEL && KMAP_LOCAL 937 help 938 This option enables additional error checking for the kmap_local 939 infrastructure. Disable for production use. 940 941config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 942 bool 943 944config DEBUG_KMAP_LOCAL_FORCE_MAP 945 bool "Enforce kmap_local temporary mappings" 946 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 947 select KMAP_LOCAL 948 select DEBUG_KMAP_LOCAL 949 help 950 This option enforces temporary mappings through the kmap_local 951 mechanism for non-highmem pages and on non-highmem systems. 952 Disable this for production systems! 953 954config DEBUG_HIGHMEM 955 bool "Highmem debugging" 956 depends on DEBUG_KERNEL && HIGHMEM 957 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 958 select DEBUG_KMAP_LOCAL 959 help 960 This option enables additional error checking for high memory 961 systems. Disable for production systems. 962 963config HAVE_DEBUG_STACKOVERFLOW 964 bool 965 966config DEBUG_STACKOVERFLOW 967 bool "Check for stack overflows" 968 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 969 help 970 Say Y here if you want to check for overflows of kernel, IRQ 971 and exception stacks (if your architecture uses them). This 972 option will show detailed messages if free stack space drops 973 below a certain limit. 974 975 These kinds of bugs usually occur when call-chains in the 976 kernel get too deep, especially when interrupts are 977 involved. 978 979 Use this in cases where you see apparently random memory 980 corruption, especially if it appears in 'struct thread_info' 981 982 If in doubt, say "N". 983 984source "lib/Kconfig.kasan" 985source "lib/Kconfig.kfence" 986source "lib/Kconfig.kmsan" 987 988endmenu # "Memory Debugging" 989 990config DEBUG_SHIRQ 991 bool "Debug shared IRQ handlers" 992 depends on DEBUG_KERNEL 993 help 994 Enable this to generate a spurious interrupt just before a shared 995 interrupt handler is deregistered (generating one when registering 996 is currently disabled). Drivers need to handle this correctly. Some 997 don't and need to be caught. 998 999menu "Debug Oops, Lockups and Hangs" 1000 1001config PANIC_ON_OOPS 1002 bool "Panic on Oops" 1003 help 1004 Say Y here to enable the kernel to panic when it oopses. This 1005 has the same effect as setting oops=panic on the kernel command 1006 line. 1007 1008 This feature is useful to ensure that the kernel does not do 1009 anything erroneous after an oops which could result in data 1010 corruption or other issues. 1011 1012 Say N if unsure. 1013 1014config PANIC_ON_OOPS_VALUE 1015 int 1016 range 0 1 1017 default 0 if !PANIC_ON_OOPS 1018 default 1 if PANIC_ON_OOPS 1019 1020config PANIC_TIMEOUT 1021 int "panic timeout" 1022 default 0 1023 help 1024 Set the timeout value (in seconds) until a reboot occurs when 1025 the kernel panics. If n = 0, then we wait forever. A timeout 1026 value n > 0 will wait n seconds before rebooting, while a timeout 1027 value n < 0 will reboot immediately. 1028 1029config LOCKUP_DETECTOR 1030 bool 1031 1032config SOFTLOCKUP_DETECTOR 1033 bool "Detect Soft Lockups" 1034 depends on DEBUG_KERNEL && !S390 1035 select LOCKUP_DETECTOR 1036 help 1037 Say Y here to enable the kernel to act as a watchdog to detect 1038 soft lockups. 1039 1040 Softlockups are bugs that cause the kernel to loop in kernel 1041 mode for more than 20 seconds, without giving other tasks a 1042 chance to run. The current stack trace is displayed upon 1043 detection and the system will stay locked up. 1044 1045config BOOTPARAM_SOFTLOCKUP_PANIC 1046 bool "Panic (Reboot) On Soft Lockups" 1047 depends on SOFTLOCKUP_DETECTOR 1048 help 1049 Say Y here to enable the kernel to panic on "soft lockups", 1050 which are bugs that cause the kernel to loop in kernel 1051 mode for more than 20 seconds (configurable using the watchdog_thresh 1052 sysctl), without giving other tasks a chance to run. 1053 1054 The panic can be used in combination with panic_timeout, 1055 to cause the system to reboot automatically after a 1056 lockup has been detected. This feature is useful for 1057 high-availability systems that have uptime guarantees and 1058 where a lockup must be resolved ASAP. 1059 1060 Say N if unsure. 1061 1062config HARDLOCKUP_DETECTOR_PERF 1063 bool 1064 select SOFTLOCKUP_DETECTOR 1065 1066# 1067# Enables a timestamp based low pass filter to compensate for perf based 1068# hard lockup detection which runs too fast due to turbo modes. 1069# 1070config HARDLOCKUP_CHECK_TIMESTAMP 1071 bool 1072 1073# 1074# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1075# lockup detector rather than the perf based detector. 1076# 1077config HARDLOCKUP_DETECTOR 1078 bool "Detect Hard Lockups" 1079 depends on DEBUG_KERNEL && !S390 1080 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1081 select LOCKUP_DETECTOR 1082 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1083 help 1084 Say Y here to enable the kernel to act as a watchdog to detect 1085 hard lockups. 1086 1087 Hardlockups are bugs that cause the CPU to loop in kernel mode 1088 for more than 10 seconds, without letting other interrupts have a 1089 chance to run. The current stack trace is displayed upon detection 1090 and the system will stay locked up. 1091 1092config BOOTPARAM_HARDLOCKUP_PANIC 1093 bool "Panic (Reboot) On Hard Lockups" 1094 depends on HARDLOCKUP_DETECTOR 1095 help 1096 Say Y here to enable the kernel to panic on "hard lockups", 1097 which are bugs that cause the kernel to loop in kernel 1098 mode with interrupts disabled for more than 10 seconds (configurable 1099 using the watchdog_thresh sysctl). 1100 1101 Say N if unsure. 1102 1103config DETECT_HUNG_TASK 1104 bool "Detect Hung Tasks" 1105 depends on DEBUG_KERNEL 1106 default SOFTLOCKUP_DETECTOR 1107 help 1108 Say Y here to enable the kernel to detect "hung tasks", 1109 which are bugs that cause the task to be stuck in 1110 uninterruptible "D" state indefinitely. 1111 1112 When a hung task is detected, the kernel will print the 1113 current stack trace (which you should report), but the 1114 task will stay in uninterruptible state. If lockdep is 1115 enabled then all held locks will also be reported. This 1116 feature has negligible overhead. 1117 1118config DEFAULT_HUNG_TASK_TIMEOUT 1119 int "Default timeout for hung task detection (in seconds)" 1120 depends on DETECT_HUNG_TASK 1121 default 120 1122 help 1123 This option controls the default timeout (in seconds) used 1124 to determine when a task has become non-responsive and should 1125 be considered hung. 1126 1127 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1128 sysctl or by writing a value to 1129 /proc/sys/kernel/hung_task_timeout_secs. 1130 1131 A timeout of 0 disables the check. The default is two minutes. 1132 Keeping the default should be fine in most cases. 1133 1134config BOOTPARAM_HUNG_TASK_PANIC 1135 bool "Panic (Reboot) On Hung Tasks" 1136 depends on DETECT_HUNG_TASK 1137 help 1138 Say Y here to enable the kernel to panic on "hung tasks", 1139 which are bugs that cause the kernel to leave a task stuck 1140 in uninterruptible "D" state. 1141 1142 The panic can be used in combination with panic_timeout, 1143 to cause the system to reboot automatically after a 1144 hung task has been detected. This feature is useful for 1145 high-availability systems that have uptime guarantees and 1146 where a hung tasks must be resolved ASAP. 1147 1148 Say N if unsure. 1149 1150config WQ_WATCHDOG 1151 bool "Detect Workqueue Stalls" 1152 depends on DEBUG_KERNEL 1153 help 1154 Say Y here to enable stall detection on workqueues. If a 1155 worker pool doesn't make forward progress on a pending work 1156 item for over a given amount of time, 30s by default, a 1157 warning message is printed along with dump of workqueue 1158 state. This can be configured through kernel parameter 1159 "workqueue.watchdog_thresh" and its sysfs counterpart. 1160 1161config TEST_LOCKUP 1162 tristate "Test module to generate lockups" 1163 depends on m 1164 help 1165 This builds the "test_lockup" module that helps to make sure 1166 that watchdogs and lockup detectors are working properly. 1167 1168 Depending on module parameters it could emulate soft or hard 1169 lockup, "hung task", or locking arbitrary lock for a long time. 1170 Also it could generate series of lockups with cooling-down periods. 1171 1172 If unsure, say N. 1173 1174endmenu # "Debug lockups and hangs" 1175 1176menu "Scheduler Debugging" 1177 1178config SCHED_DEBUG 1179 bool "Collect scheduler debugging info" 1180 depends on DEBUG_KERNEL && PROC_FS 1181 default y 1182 help 1183 If you say Y here, the /proc/sched_debug file will be provided 1184 that can help debug the scheduler. The runtime overhead of this 1185 option is minimal. 1186 1187config SCHED_INFO 1188 bool 1189 default n 1190 1191config SCHEDSTATS 1192 bool "Collect scheduler statistics" 1193 depends on DEBUG_KERNEL && PROC_FS 1194 select SCHED_INFO 1195 help 1196 If you say Y here, additional code will be inserted into the 1197 scheduler and related routines to collect statistics about 1198 scheduler behavior and provide them in /proc/schedstat. These 1199 stats may be useful for both tuning and debugging the scheduler 1200 If you aren't debugging the scheduler or trying to tune a specific 1201 application, you can say N to avoid the very slight overhead 1202 this adds. 1203 1204endmenu 1205 1206config DEBUG_TIMEKEEPING 1207 bool "Enable extra timekeeping sanity checking" 1208 help 1209 This option will enable additional timekeeping sanity checks 1210 which may be helpful when diagnosing issues where timekeeping 1211 problems are suspected. 1212 1213 This may include checks in the timekeeping hotpaths, so this 1214 option may have a (very small) performance impact to some 1215 workloads. 1216 1217 If unsure, say N. 1218 1219config DEBUG_PREEMPT 1220 bool "Debug preemptible kernel" 1221 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1222 default y 1223 help 1224 If you say Y here then the kernel will use a debug variant of the 1225 commonly used smp_processor_id() function and will print warnings 1226 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1227 will detect preemption count underflows. 1228 1229menu "Lock Debugging (spinlocks, mutexes, etc...)" 1230 1231config LOCK_DEBUGGING_SUPPORT 1232 bool 1233 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1234 default y 1235 1236config PROVE_LOCKING 1237 bool "Lock debugging: prove locking correctness" 1238 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1239 select LOCKDEP 1240 select DEBUG_SPINLOCK 1241 select DEBUG_MUTEXES if !PREEMPT_RT 1242 select DEBUG_RT_MUTEXES if RT_MUTEXES 1243 select DEBUG_RWSEMS 1244 select DEBUG_WW_MUTEX_SLOWPATH 1245 select DEBUG_LOCK_ALLOC 1246 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1247 select TRACE_IRQFLAGS 1248 default n 1249 help 1250 This feature enables the kernel to prove that all locking 1251 that occurs in the kernel runtime is mathematically 1252 correct: that under no circumstance could an arbitrary (and 1253 not yet triggered) combination of observed locking 1254 sequences (on an arbitrary number of CPUs, running an 1255 arbitrary number of tasks and interrupt contexts) cause a 1256 deadlock. 1257 1258 In short, this feature enables the kernel to report locking 1259 related deadlocks before they actually occur. 1260 1261 The proof does not depend on how hard and complex a 1262 deadlock scenario would be to trigger: how many 1263 participant CPUs, tasks and irq-contexts would be needed 1264 for it to trigger. The proof also does not depend on 1265 timing: if a race and a resulting deadlock is possible 1266 theoretically (no matter how unlikely the race scenario 1267 is), it will be proven so and will immediately be 1268 reported by the kernel (once the event is observed that 1269 makes the deadlock theoretically possible). 1270 1271 If a deadlock is impossible (i.e. the locking rules, as 1272 observed by the kernel, are mathematically correct), the 1273 kernel reports nothing. 1274 1275 NOTE: this feature can also be enabled for rwlocks, mutexes 1276 and rwsems - in which case all dependencies between these 1277 different locking variants are observed and mapped too, and 1278 the proof of observed correctness is also maintained for an 1279 arbitrary combination of these separate locking variants. 1280 1281 For more details, see Documentation/locking/lockdep-design.rst. 1282 1283config PROVE_RAW_LOCK_NESTING 1284 bool "Enable raw_spinlock - spinlock nesting checks" 1285 depends on PROVE_LOCKING 1286 default n 1287 help 1288 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1289 that the lock nesting rules for PREEMPT_RT enabled kernels are 1290 not violated. 1291 1292 NOTE: There are known nesting problems. So if you enable this 1293 option expect lockdep splats until these problems have been fully 1294 addressed which is work in progress. This config switch allows to 1295 identify and analyze these problems. It will be removed and the 1296 check permanently enabled once the main issues have been fixed. 1297 1298 If unsure, select N. 1299 1300config LOCK_STAT 1301 bool "Lock usage statistics" 1302 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1303 select LOCKDEP 1304 select DEBUG_SPINLOCK 1305 select DEBUG_MUTEXES if !PREEMPT_RT 1306 select DEBUG_RT_MUTEXES if RT_MUTEXES 1307 select DEBUG_LOCK_ALLOC 1308 default n 1309 help 1310 This feature enables tracking lock contention points 1311 1312 For more details, see Documentation/locking/lockstat.rst 1313 1314 This also enables lock events required by "perf lock", 1315 subcommand of perf. 1316 If you want to use "perf lock", you also need to turn on 1317 CONFIG_EVENT_TRACING. 1318 1319 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1320 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1321 1322config DEBUG_RT_MUTEXES 1323 bool "RT Mutex debugging, deadlock detection" 1324 depends on DEBUG_KERNEL && RT_MUTEXES 1325 help 1326 This allows rt mutex semantics violations and rt mutex related 1327 deadlocks (lockups) to be detected and reported automatically. 1328 1329config DEBUG_SPINLOCK 1330 bool "Spinlock and rw-lock debugging: basic checks" 1331 depends on DEBUG_KERNEL 1332 select UNINLINE_SPIN_UNLOCK 1333 help 1334 Say Y here and build SMP to catch missing spinlock initialization 1335 and certain other kinds of spinlock errors commonly made. This is 1336 best used in conjunction with the NMI watchdog so that spinlock 1337 deadlocks are also debuggable. 1338 1339config DEBUG_MUTEXES 1340 bool "Mutex debugging: basic checks" 1341 depends on DEBUG_KERNEL && !PREEMPT_RT 1342 help 1343 This feature allows mutex semantics violations to be detected and 1344 reported. 1345 1346config DEBUG_WW_MUTEX_SLOWPATH 1347 bool "Wait/wound mutex debugging: Slowpath testing" 1348 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1349 select DEBUG_LOCK_ALLOC 1350 select DEBUG_SPINLOCK 1351 select DEBUG_MUTEXES if !PREEMPT_RT 1352 select DEBUG_RT_MUTEXES if PREEMPT_RT 1353 help 1354 This feature enables slowpath testing for w/w mutex users by 1355 injecting additional -EDEADLK wound/backoff cases. Together with 1356 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1357 will test all possible w/w mutex interface abuse with the 1358 exception of simply not acquiring all the required locks. 1359 Note that this feature can introduce significant overhead, so 1360 it really should not be enabled in a production or distro kernel, 1361 even a debug kernel. If you are a driver writer, enable it. If 1362 you are a distro, do not. 1363 1364config DEBUG_RWSEMS 1365 bool "RW Semaphore debugging: basic checks" 1366 depends on DEBUG_KERNEL 1367 help 1368 This debugging feature allows mismatched rw semaphore locks 1369 and unlocks to be detected and reported. 1370 1371config DEBUG_LOCK_ALLOC 1372 bool "Lock debugging: detect incorrect freeing of live locks" 1373 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1374 select DEBUG_SPINLOCK 1375 select DEBUG_MUTEXES if !PREEMPT_RT 1376 select DEBUG_RT_MUTEXES if RT_MUTEXES 1377 select LOCKDEP 1378 help 1379 This feature will check whether any held lock (spinlock, rwlock, 1380 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1381 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1382 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1383 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1384 held during task exit. 1385 1386config LOCKDEP 1387 bool 1388 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1389 select STACKTRACE 1390 select KALLSYMS 1391 select KALLSYMS_ALL 1392 1393config LOCKDEP_SMALL 1394 bool 1395 1396config LOCKDEP_BITS 1397 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1398 depends on LOCKDEP && !LOCKDEP_SMALL 1399 range 10 30 1400 default 15 1401 help 1402 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1403 1404config LOCKDEP_CHAINS_BITS 1405 int "Bitsize for MAX_LOCKDEP_CHAINS" 1406 depends on LOCKDEP && !LOCKDEP_SMALL 1407 range 10 30 1408 default 16 1409 help 1410 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1411 1412config LOCKDEP_STACK_TRACE_BITS 1413 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1414 depends on LOCKDEP && !LOCKDEP_SMALL 1415 range 10 30 1416 default 19 1417 help 1418 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1419 1420config LOCKDEP_STACK_TRACE_HASH_BITS 1421 int "Bitsize for STACK_TRACE_HASH_SIZE" 1422 depends on LOCKDEP && !LOCKDEP_SMALL 1423 range 10 30 1424 default 14 1425 help 1426 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1427 1428config LOCKDEP_CIRCULAR_QUEUE_BITS 1429 int "Bitsize for elements in circular_queue struct" 1430 depends on LOCKDEP 1431 range 10 30 1432 default 12 1433 help 1434 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1435 1436config DEBUG_LOCKDEP 1437 bool "Lock dependency engine debugging" 1438 depends on DEBUG_KERNEL && LOCKDEP 1439 select DEBUG_IRQFLAGS 1440 help 1441 If you say Y here, the lock dependency engine will do 1442 additional runtime checks to debug itself, at the price 1443 of more runtime overhead. 1444 1445config DEBUG_ATOMIC_SLEEP 1446 bool "Sleep inside atomic section checking" 1447 select PREEMPT_COUNT 1448 depends on DEBUG_KERNEL 1449 depends on !ARCH_NO_PREEMPT 1450 help 1451 If you say Y here, various routines which may sleep will become very 1452 noisy if they are called inside atomic sections: when a spinlock is 1453 held, inside an rcu read side critical section, inside preempt disabled 1454 sections, inside an interrupt, etc... 1455 1456config DEBUG_LOCKING_API_SELFTESTS 1457 bool "Locking API boot-time self-tests" 1458 depends on DEBUG_KERNEL 1459 help 1460 Say Y here if you want the kernel to run a short self-test during 1461 bootup. The self-test checks whether common types of locking bugs 1462 are detected by debugging mechanisms or not. (if you disable 1463 lock debugging then those bugs won't be detected of course.) 1464 The following locking APIs are covered: spinlocks, rwlocks, 1465 mutexes and rwsems. 1466 1467config LOCK_TORTURE_TEST 1468 tristate "torture tests for locking" 1469 depends on DEBUG_KERNEL 1470 select TORTURE_TEST 1471 help 1472 This option provides a kernel module that runs torture tests 1473 on kernel locking primitives. The kernel module may be built 1474 after the fact on the running kernel to be tested, if desired. 1475 1476 Say Y here if you want kernel locking-primitive torture tests 1477 to be built into the kernel. 1478 Say M if you want these torture tests to build as a module. 1479 Say N if you are unsure. 1480 1481config WW_MUTEX_SELFTEST 1482 tristate "Wait/wound mutex selftests" 1483 help 1484 This option provides a kernel module that runs tests on the 1485 on the struct ww_mutex locking API. 1486 1487 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1488 with this test harness. 1489 1490 Say M if you want these self tests to build as a module. 1491 Say N if you are unsure. 1492 1493config SCF_TORTURE_TEST 1494 tristate "torture tests for smp_call_function*()" 1495 depends on DEBUG_KERNEL 1496 select TORTURE_TEST 1497 help 1498 This option provides a kernel module that runs torture tests 1499 on the smp_call_function() family of primitives. The kernel 1500 module may be built after the fact on the running kernel to 1501 be tested, if desired. 1502 1503config CSD_LOCK_WAIT_DEBUG 1504 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1505 depends on DEBUG_KERNEL 1506 depends on 64BIT 1507 default n 1508 help 1509 This option enables debug prints when CPUs are slow to respond 1510 to the smp_call_function*() IPI wrappers. These debug prints 1511 include the IPI handler function currently executing (if any) 1512 and relevant stack traces. 1513 1514endmenu # lock debugging 1515 1516config TRACE_IRQFLAGS 1517 depends on TRACE_IRQFLAGS_SUPPORT 1518 bool 1519 help 1520 Enables hooks to interrupt enabling and disabling for 1521 either tracing or lock debugging. 1522 1523config TRACE_IRQFLAGS_NMI 1524 def_bool y 1525 depends on TRACE_IRQFLAGS 1526 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1527 1528config DEBUG_IRQFLAGS 1529 bool "Debug IRQ flag manipulation" 1530 help 1531 Enables checks for potentially unsafe enabling or disabling of 1532 interrupts, such as calling raw_local_irq_restore() when interrupts 1533 are enabled. 1534 1535config STACKTRACE 1536 bool "Stack backtrace support" 1537 depends on STACKTRACE_SUPPORT 1538 help 1539 This option causes the kernel to create a /proc/pid/stack for 1540 every process, showing its current stack trace. 1541 It is also used by various kernel debugging features that require 1542 stack trace generation. 1543 1544config WARN_ALL_UNSEEDED_RANDOM 1545 bool "Warn for all uses of unseeded randomness" 1546 default n 1547 help 1548 Some parts of the kernel contain bugs relating to their use of 1549 cryptographically secure random numbers before it's actually possible 1550 to generate those numbers securely. This setting ensures that these 1551 flaws don't go unnoticed, by enabling a message, should this ever 1552 occur. This will allow people with obscure setups to know when things 1553 are going wrong, so that they might contact developers about fixing 1554 it. 1555 1556 Unfortunately, on some models of some architectures getting 1557 a fully seeded CRNG is extremely difficult, and so this can 1558 result in dmesg getting spammed for a surprisingly long 1559 time. This is really bad from a security perspective, and 1560 so architecture maintainers really need to do what they can 1561 to get the CRNG seeded sooner after the system is booted. 1562 However, since users cannot do anything actionable to 1563 address this, by default this option is disabled. 1564 1565 Say Y here if you want to receive warnings for all uses of 1566 unseeded randomness. This will be of use primarily for 1567 those developers interested in improving the security of 1568 Linux kernels running on their architecture (or 1569 subarchitecture). 1570 1571config DEBUG_KOBJECT 1572 bool "kobject debugging" 1573 depends on DEBUG_KERNEL 1574 help 1575 If you say Y here, some extra kobject debugging messages will be sent 1576 to the syslog. 1577 1578config DEBUG_KOBJECT_RELEASE 1579 bool "kobject release debugging" 1580 depends on DEBUG_OBJECTS_TIMERS 1581 help 1582 kobjects are reference counted objects. This means that their 1583 last reference count put is not predictable, and the kobject can 1584 live on past the point at which a driver decides to drop its 1585 initial reference to the kobject gained on allocation. An 1586 example of this would be a struct device which has just been 1587 unregistered. 1588 1589 However, some buggy drivers assume that after such an operation, 1590 the memory backing the kobject can be immediately freed. This 1591 goes completely against the principles of a refcounted object. 1592 1593 If you say Y here, the kernel will delay the release of kobjects 1594 on the last reference count to improve the visibility of this 1595 kind of kobject release bug. 1596 1597config HAVE_DEBUG_BUGVERBOSE 1598 bool 1599 1600menu "Debug kernel data structures" 1601 1602config DEBUG_LIST 1603 bool "Debug linked list manipulation" 1604 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1605 help 1606 Enable this to turn on extended checks in the linked-list 1607 walking routines. 1608 1609 If unsure, say N. 1610 1611config DEBUG_PLIST 1612 bool "Debug priority linked list manipulation" 1613 depends on DEBUG_KERNEL 1614 help 1615 Enable this to turn on extended checks in the priority-ordered 1616 linked-list (plist) walking routines. This checks the entire 1617 list multiple times during each manipulation. 1618 1619 If unsure, say N. 1620 1621config DEBUG_SG 1622 bool "Debug SG table operations" 1623 depends on DEBUG_KERNEL 1624 help 1625 Enable this to turn on checks on scatter-gather tables. This can 1626 help find problems with drivers that do not properly initialize 1627 their sg tables. 1628 1629 If unsure, say N. 1630 1631config DEBUG_NOTIFIERS 1632 bool "Debug notifier call chains" 1633 depends on DEBUG_KERNEL 1634 help 1635 Enable this to turn on sanity checking for notifier call chains. 1636 This is most useful for kernel developers to make sure that 1637 modules properly unregister themselves from notifier chains. 1638 This is a relatively cheap check but if you care about maximum 1639 performance, say N. 1640 1641config BUG_ON_DATA_CORRUPTION 1642 bool "Trigger a BUG when data corruption is detected" 1643 select DEBUG_LIST 1644 help 1645 Select this option if the kernel should BUG when it encounters 1646 data corruption in kernel memory structures when they get checked 1647 for validity. 1648 1649 If unsure, say N. 1650 1651config DEBUG_MAPLE_TREE 1652 bool "Debug maple trees" 1653 depends on DEBUG_KERNEL 1654 help 1655 Enable maple tree debugging information and extra validations. 1656 1657 If unsure, say N. 1658 1659endmenu 1660 1661config DEBUG_CREDENTIALS 1662 bool "Debug credential management" 1663 depends on DEBUG_KERNEL 1664 help 1665 Enable this to turn on some debug checking for credential 1666 management. The additional code keeps track of the number of 1667 pointers from task_structs to any given cred struct, and checks to 1668 see that this number never exceeds the usage count of the cred 1669 struct. 1670 1671 Furthermore, if SELinux is enabled, this also checks that the 1672 security pointer in the cred struct is never seen to be invalid. 1673 1674 If unsure, say N. 1675 1676source "kernel/rcu/Kconfig.debug" 1677 1678config DEBUG_WQ_FORCE_RR_CPU 1679 bool "Force round-robin CPU selection for unbound work items" 1680 depends on DEBUG_KERNEL 1681 default n 1682 help 1683 Workqueue used to implicitly guarantee that work items queued 1684 without explicit CPU specified are put on the local CPU. This 1685 guarantee is no longer true and while local CPU is still 1686 preferred work items may be put on foreign CPUs. Kernel 1687 parameter "workqueue.debug_force_rr_cpu" is added to force 1688 round-robin CPU selection to flush out usages which depend on the 1689 now broken guarantee. This config option enables the debug 1690 feature by default. When enabled, memory and cache locality will 1691 be impacted. 1692 1693config CPU_HOTPLUG_STATE_CONTROL 1694 bool "Enable CPU hotplug state control" 1695 depends on DEBUG_KERNEL 1696 depends on HOTPLUG_CPU 1697 default n 1698 help 1699 Allows to write steps between "offline" and "online" to the CPUs 1700 sysfs target file so states can be stepped granular. This is a debug 1701 option for now as the hotplug machinery cannot be stopped and 1702 restarted at arbitrary points yet. 1703 1704 Say N if your are unsure. 1705 1706config LATENCYTOP 1707 bool "Latency measuring infrastructure" 1708 depends on DEBUG_KERNEL 1709 depends on STACKTRACE_SUPPORT 1710 depends on PROC_FS 1711 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1712 select KALLSYMS 1713 select KALLSYMS_ALL 1714 select STACKTRACE 1715 select SCHEDSTATS 1716 help 1717 Enable this option if you want to use the LatencyTOP tool 1718 to find out which userspace is blocking on what kernel operations. 1719 1720source "kernel/trace/Kconfig" 1721 1722config PROVIDE_OHCI1394_DMA_INIT 1723 bool "Remote debugging over FireWire early on boot" 1724 depends on PCI && X86 1725 help 1726 If you want to debug problems which hang or crash the kernel early 1727 on boot and the crashing machine has a FireWire port, you can use 1728 this feature to remotely access the memory of the crashed machine 1729 over FireWire. This employs remote DMA as part of the OHCI1394 1730 specification which is now the standard for FireWire controllers. 1731 1732 With remote DMA, you can monitor the printk buffer remotely using 1733 firescope and access all memory below 4GB using fireproxy from gdb. 1734 Even controlling a kernel debugger is possible using remote DMA. 1735 1736 Usage: 1737 1738 If ohci1394_dma=early is used as boot parameter, it will initialize 1739 all OHCI1394 controllers which are found in the PCI config space. 1740 1741 As all changes to the FireWire bus such as enabling and disabling 1742 devices cause a bus reset and thereby disable remote DMA for all 1743 devices, be sure to have the cable plugged and FireWire enabled on 1744 the debugging host before booting the debug target for debugging. 1745 1746 This code (~1k) is freed after boot. By then, the firewire stack 1747 in charge of the OHCI-1394 controllers should be used instead. 1748 1749 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1750 1751source "samples/Kconfig" 1752 1753config ARCH_HAS_DEVMEM_IS_ALLOWED 1754 bool 1755 1756config STRICT_DEVMEM 1757 bool "Filter access to /dev/mem" 1758 depends on MMU && DEVMEM 1759 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1760 default y if PPC || X86 || ARM64 1761 help 1762 If this option is disabled, you allow userspace (root) access to all 1763 of memory, including kernel and userspace memory. Accidental 1764 access to this is obviously disastrous, but specific access can 1765 be used by people debugging the kernel. Note that with PAT support 1766 enabled, even in this case there are restrictions on /dev/mem 1767 use due to the cache aliasing requirements. 1768 1769 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1770 file only allows userspace access to PCI space and the BIOS code and 1771 data regions. This is sufficient for dosemu and X and all common 1772 users of /dev/mem. 1773 1774 If in doubt, say Y. 1775 1776config IO_STRICT_DEVMEM 1777 bool "Filter I/O access to /dev/mem" 1778 depends on STRICT_DEVMEM 1779 help 1780 If this option is disabled, you allow userspace (root) access to all 1781 io-memory regardless of whether a driver is actively using that 1782 range. Accidental access to this is obviously disastrous, but 1783 specific access can be used by people debugging kernel drivers. 1784 1785 If this option is switched on, the /dev/mem file only allows 1786 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1787 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1788 if the driver using a given range cannot be disabled. 1789 1790 If in doubt, say Y. 1791 1792menu "$(SRCARCH) Debugging" 1793 1794source "arch/$(SRCARCH)/Kconfig.debug" 1795 1796endmenu 1797 1798menu "Kernel Testing and Coverage" 1799 1800source "lib/kunit/Kconfig" 1801 1802config NOTIFIER_ERROR_INJECTION 1803 tristate "Notifier error injection" 1804 depends on DEBUG_KERNEL 1805 select DEBUG_FS 1806 help 1807 This option provides the ability to inject artificial errors to 1808 specified notifier chain callbacks. It is useful to test the error 1809 handling of notifier call chain failures. 1810 1811 Say N if unsure. 1812 1813config PM_NOTIFIER_ERROR_INJECT 1814 tristate "PM notifier error injection module" 1815 depends on PM && NOTIFIER_ERROR_INJECTION 1816 default m if PM_DEBUG 1817 help 1818 This option provides the ability to inject artificial errors to 1819 PM notifier chain callbacks. It is controlled through debugfs 1820 interface /sys/kernel/debug/notifier-error-inject/pm 1821 1822 If the notifier call chain should be failed with some events 1823 notified, write the error code to "actions/<notifier event>/error". 1824 1825 Example: Inject PM suspend error (-12 = -ENOMEM) 1826 1827 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1828 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1829 # echo mem > /sys/power/state 1830 bash: echo: write error: Cannot allocate memory 1831 1832 To compile this code as a module, choose M here: the module will 1833 be called pm-notifier-error-inject. 1834 1835 If unsure, say N. 1836 1837config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1838 tristate "OF reconfig notifier error injection module" 1839 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1840 help 1841 This option provides the ability to inject artificial errors to 1842 OF reconfig notifier chain callbacks. It is controlled 1843 through debugfs interface under 1844 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1845 1846 If the notifier call chain should be failed with some events 1847 notified, write the error code to "actions/<notifier event>/error". 1848 1849 To compile this code as a module, choose M here: the module will 1850 be called of-reconfig-notifier-error-inject. 1851 1852 If unsure, say N. 1853 1854config NETDEV_NOTIFIER_ERROR_INJECT 1855 tristate "Netdev notifier error injection module" 1856 depends on NET && NOTIFIER_ERROR_INJECTION 1857 help 1858 This option provides the ability to inject artificial errors to 1859 netdevice notifier chain callbacks. It is controlled through debugfs 1860 interface /sys/kernel/debug/notifier-error-inject/netdev 1861 1862 If the notifier call chain should be failed with some events 1863 notified, write the error code to "actions/<notifier event>/error". 1864 1865 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1866 1867 # cd /sys/kernel/debug/notifier-error-inject/netdev 1868 # echo -22 > actions/NETDEV_CHANGEMTU/error 1869 # ip link set eth0 mtu 1024 1870 RTNETLINK answers: Invalid argument 1871 1872 To compile this code as a module, choose M here: the module will 1873 be called netdev-notifier-error-inject. 1874 1875 If unsure, say N. 1876 1877config FUNCTION_ERROR_INJECTION 1878 bool "Fault-injections of functions" 1879 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1880 help 1881 Add fault injections into various functions that are annotated with 1882 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1883 value of theses functions. This is useful to test error paths of code. 1884 1885 If unsure, say N 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 || HAVE_NOINSTR_HACK || \ 1996 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 1997 select DEBUG_FS 1998 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1999 select OBJTOOL if HAVE_NOINSTR_HACK 2000 help 2001 KCOV exposes kernel code coverage information in a form suitable 2002 for coverage-guided fuzzing (randomized testing). 2003 2004 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2005 different machines and across reboots. If you need stable PC values, 2006 disable RANDOMIZE_BASE. 2007 2008 For more details, see Documentation/dev-tools/kcov.rst. 2009 2010config KCOV_ENABLE_COMPARISONS 2011 bool "Enable comparison operands collection by KCOV" 2012 depends on KCOV 2013 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2014 help 2015 KCOV also exposes operands of every comparison in the instrumented 2016 code along with operand sizes and PCs of the comparison instructions. 2017 These operands can be used by fuzzing engines to improve the quality 2018 of fuzzing coverage. 2019 2020config KCOV_INSTRUMENT_ALL 2021 bool "Instrument all code by default" 2022 depends on KCOV 2023 default y 2024 help 2025 If you are doing generic system call fuzzing (like e.g. syzkaller), 2026 then you will want to instrument the whole kernel and you should 2027 say y here. If you are doing more targeted fuzzing (like e.g. 2028 filesystem fuzzing with AFL) then you will want to enable coverage 2029 for more specific subsets of files, and should say n here. 2030 2031config KCOV_IRQ_AREA_SIZE 2032 hex "Size of interrupt coverage collection area in words" 2033 depends on KCOV 2034 default 0x40000 2035 help 2036 KCOV uses preallocated per-cpu areas to collect coverage from 2037 soft interrupts. This specifies the size of those areas in the 2038 number of unsigned long words. 2039 2040menuconfig RUNTIME_TESTING_MENU 2041 bool "Runtime Testing" 2042 def_bool y 2043 2044if RUNTIME_TESTING_MENU 2045 2046config LKDTM 2047 tristate "Linux Kernel Dump Test Tool Module" 2048 depends on DEBUG_FS 2049 help 2050 This module enables testing of the different dumping mechanisms by 2051 inducing system failures at predefined crash points. 2052 If you don't need it: say N 2053 Choose M here to compile this code as a module. The module will be 2054 called lkdtm. 2055 2056 Documentation on how to use the module can be found in 2057 Documentation/fault-injection/provoke-crashes.rst 2058 2059config CPUMASK_KUNIT_TEST 2060 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2061 depends on KUNIT 2062 default KUNIT_ALL_TESTS 2063 help 2064 Enable to turn on cpumask tests, running at boot or module load time. 2065 2066 For more information on KUnit and unit tests in general, please refer 2067 to the KUnit documentation in Documentation/dev-tools/kunit/. 2068 2069 If unsure, say N. 2070 2071config TEST_LIST_SORT 2072 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2073 depends on KUNIT 2074 default KUNIT_ALL_TESTS 2075 help 2076 Enable this to turn on 'list_sort()' function test. This test is 2077 executed only once during system boot (so affects only boot time), 2078 or at module load time. 2079 2080 If unsure, say N. 2081 2082config TEST_MIN_HEAP 2083 tristate "Min heap test" 2084 depends on DEBUG_KERNEL || m 2085 help 2086 Enable this to turn on min heap function tests. This test is 2087 executed only once during system boot (so affects only boot time), 2088 or at module load time. 2089 2090 If unsure, say N. 2091 2092config TEST_SORT 2093 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2094 depends on KUNIT 2095 default KUNIT_ALL_TESTS 2096 help 2097 This option enables the self-test function of 'sort()' at boot, 2098 or at module load time. 2099 2100 If unsure, say N. 2101 2102config TEST_DIV64 2103 tristate "64bit/32bit division and modulo test" 2104 depends on DEBUG_KERNEL || m 2105 help 2106 Enable this to turn on 'do_div()' function test. This test is 2107 executed only once during system boot (so affects only boot time), 2108 or at module load time. 2109 2110 If unsure, say N. 2111 2112config KPROBES_SANITY_TEST 2113 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2114 depends on DEBUG_KERNEL 2115 depends on KPROBES 2116 depends on KUNIT 2117 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2118 default KUNIT_ALL_TESTS 2119 help 2120 This option provides for testing basic kprobes functionality on 2121 boot. Samples of kprobe and kretprobe are inserted and 2122 verified for functionality. 2123 2124 Say N if you are unsure. 2125 2126config FPROBE_SANITY_TEST 2127 bool "Self test for fprobe" 2128 depends on DEBUG_KERNEL 2129 depends on FPROBE 2130 depends on KUNIT=y 2131 help 2132 This option will enable testing the fprobe when the system boot. 2133 A series of tests are made to verify that the fprobe is functioning 2134 properly. 2135 2136 Say N if you are unsure. 2137 2138config BACKTRACE_SELF_TEST 2139 tristate "Self test for the backtrace code" 2140 depends on DEBUG_KERNEL 2141 help 2142 This option provides a kernel module that can be used to test 2143 the kernel stack backtrace code. This option is not useful 2144 for distributions or general kernels, but only for kernel 2145 developers working on architecture code. 2146 2147 Note that if you want to also test saved backtraces, you will 2148 have to enable STACKTRACE as well. 2149 2150 Say N if you are unsure. 2151 2152config TEST_REF_TRACKER 2153 tristate "Self test for reference tracker" 2154 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2155 select REF_TRACKER 2156 help 2157 This option provides a kernel module performing tests 2158 using reference tracker infrastructure. 2159 2160 Say N if you are unsure. 2161 2162config RBTREE_TEST 2163 tristate "Red-Black tree test" 2164 depends on DEBUG_KERNEL 2165 help 2166 A benchmark measuring the performance of the rbtree library. 2167 Also includes rbtree invariant checks. 2168 2169config REED_SOLOMON_TEST 2170 tristate "Reed-Solomon library test" 2171 depends on DEBUG_KERNEL || m 2172 select REED_SOLOMON 2173 select REED_SOLOMON_ENC16 2174 select REED_SOLOMON_DEC16 2175 help 2176 This option enables the self-test function of rslib at boot, 2177 or at module load time. 2178 2179 If unsure, say N. 2180 2181config INTERVAL_TREE_TEST 2182 tristate "Interval tree test" 2183 depends on DEBUG_KERNEL 2184 select INTERVAL_TREE 2185 help 2186 A benchmark measuring the performance of the interval tree library 2187 2188config PERCPU_TEST 2189 tristate "Per cpu operations test" 2190 depends on m && DEBUG_KERNEL 2191 help 2192 Enable this option to build test module which validates per-cpu 2193 operations. 2194 2195 If unsure, say N. 2196 2197config ATOMIC64_SELFTEST 2198 tristate "Perform an atomic64_t self-test" 2199 help 2200 Enable this option to test the atomic64_t functions at boot or 2201 at module load time. 2202 2203 If unsure, say N. 2204 2205config ASYNC_RAID6_TEST 2206 tristate "Self test for hardware accelerated raid6 recovery" 2207 depends on ASYNC_RAID6_RECOV 2208 select ASYNC_MEMCPY 2209 help 2210 This is a one-shot self test that permutes through the 2211 recovery of all the possible two disk failure scenarios for a 2212 N-disk array. Recovery is performed with the asynchronous 2213 raid6 recovery routines, and will optionally use an offload 2214 engine if one is available. 2215 2216 If unsure, say N. 2217 2218config TEST_HEXDUMP 2219 tristate "Test functions located in the hexdump module at runtime" 2220 2221config STRING_SELFTEST 2222 tristate "Test string functions at runtime" 2223 2224config TEST_STRING_HELPERS 2225 tristate "Test functions located in the string_helpers module at runtime" 2226 2227config TEST_STRSCPY 2228 tristate "Test strscpy*() family of functions at runtime" 2229 2230config TEST_KSTRTOX 2231 tristate "Test kstrto*() family of functions at runtime" 2232 2233config TEST_PRINTF 2234 tristate "Test printf() family of functions at runtime" 2235 2236config TEST_SCANF 2237 tristate "Test scanf() family of functions at runtime" 2238 2239config TEST_BITMAP 2240 tristate "Test bitmap_*() family of functions at runtime" 2241 help 2242 Enable this option to test the bitmap functions at boot. 2243 2244 If unsure, say N. 2245 2246config TEST_UUID 2247 tristate "Test functions located in the uuid module at runtime" 2248 2249config TEST_XARRAY 2250 tristate "Test the XArray code at runtime" 2251 2252config TEST_MAPLE_TREE 2253 select DEBUG_MAPLE_TREE 2254 tristate "Test the Maple Tree code at runtime" 2255 2256config TEST_RHASHTABLE 2257 tristate "Perform selftest on resizable hash table" 2258 help 2259 Enable this option to test the rhashtable functions at boot. 2260 2261 If unsure, say N. 2262 2263config TEST_SIPHASH 2264 tristate "Perform selftest on siphash functions" 2265 help 2266 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2267 functions on boot (or module load). 2268 2269 This is intended to help people writing architecture-specific 2270 optimized versions. If unsure, say N. 2271 2272config TEST_IDA 2273 tristate "Perform selftest on IDA functions" 2274 2275config TEST_PARMAN 2276 tristate "Perform selftest on priority array manager" 2277 depends on PARMAN 2278 help 2279 Enable this option to test priority array manager on boot 2280 (or module load). 2281 2282 If unsure, say N. 2283 2284config TEST_IRQ_TIMINGS 2285 bool "IRQ timings selftest" 2286 depends on IRQ_TIMINGS 2287 help 2288 Enable this option to test the irq timings code on boot. 2289 2290 If unsure, say N. 2291 2292config TEST_LKM 2293 tristate "Test module loading with 'hello world' module" 2294 depends on m 2295 help 2296 This builds the "test_module" module that emits "Hello, world" 2297 on printk when loaded. It is designed to be used for basic 2298 evaluation of the module loading subsystem (for example when 2299 validating module verification). It lacks any extra dependencies, 2300 and will not normally be loaded by the system unless explicitly 2301 requested by name. 2302 2303 If unsure, say N. 2304 2305config TEST_BITOPS 2306 tristate "Test module for compilation of bitops operations" 2307 depends on m 2308 help 2309 This builds the "test_bitops" module that is much like the 2310 TEST_LKM module except that it does a basic exercise of the 2311 set/clear_bit macros and get_count_order/long to make sure there are 2312 no compiler warnings from C=1 sparse checker or -Wextra 2313 compilations. It has no dependencies and doesn't run or load unless 2314 explicitly requested by name. for example: modprobe test_bitops. 2315 2316 If unsure, say N. 2317 2318config TEST_VMALLOC 2319 tristate "Test module for stress/performance analysis of vmalloc allocator" 2320 default n 2321 depends on MMU 2322 depends on m 2323 help 2324 This builds the "test_vmalloc" module that should be used for 2325 stress and performance analysis. So, any new change for vmalloc 2326 subsystem can be evaluated from performance and stability point 2327 of view. 2328 2329 If unsure, say N. 2330 2331config TEST_USER_COPY 2332 tristate "Test user/kernel boundary protections" 2333 depends on m 2334 help 2335 This builds the "test_user_copy" module that runs sanity checks 2336 on the copy_to/from_user infrastructure, making sure basic 2337 user/kernel boundary testing is working. If it fails to load, 2338 a regression has been detected in the user/kernel memory boundary 2339 protections. 2340 2341 If unsure, say N. 2342 2343config TEST_BPF 2344 tristate "Test BPF filter functionality" 2345 depends on m && NET 2346 help 2347 This builds the "test_bpf" module that runs various test vectors 2348 against the BPF interpreter or BPF JIT compiler depending on the 2349 current setting. This is in particular useful for BPF JIT compiler 2350 development, but also to run regression tests against changes in 2351 the interpreter code. It also enables test stubs for eBPF maps and 2352 verifier used by user space verifier testsuite. 2353 2354 If unsure, say N. 2355 2356config TEST_BLACKHOLE_DEV 2357 tristate "Test blackhole netdev functionality" 2358 depends on m && NET 2359 help 2360 This builds the "test_blackhole_dev" module that validates the 2361 data path through this blackhole netdev. 2362 2363 If unsure, say N. 2364 2365config FIND_BIT_BENCHMARK 2366 tristate "Test find_bit functions" 2367 help 2368 This builds the "test_find_bit" module that measure find_*_bit() 2369 functions performance. 2370 2371 If unsure, say N. 2372 2373config TEST_FIRMWARE 2374 tristate "Test firmware loading via userspace interface" 2375 depends on FW_LOADER 2376 help 2377 This builds the "test_firmware" module that creates a userspace 2378 interface for testing firmware loading. This can be used to 2379 control the triggering of firmware loading without needing an 2380 actual firmware-using device. The contents can be rechecked by 2381 userspace. 2382 2383 If unsure, say N. 2384 2385config TEST_SYSCTL 2386 tristate "sysctl test driver" 2387 depends on PROC_SYSCTL 2388 help 2389 This builds the "test_sysctl" module. This driver enables to test the 2390 proc sysctl interfaces available to drivers safely without affecting 2391 production knobs which might alter system functionality. 2392 2393 If unsure, say N. 2394 2395config BITFIELD_KUNIT 2396 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2397 depends on KUNIT 2398 default KUNIT_ALL_TESTS 2399 help 2400 Enable this option to test the bitfield functions at boot. 2401 2402 KUnit tests run during boot and output the results to the debug log 2403 in TAP format (http://testanything.org/). Only useful for kernel devs 2404 running the KUnit test harness, and not intended for inclusion into a 2405 production build. 2406 2407 For more information on KUnit and unit tests in general please refer 2408 to the KUnit documentation in Documentation/dev-tools/kunit/. 2409 2410 If unsure, say N. 2411 2412config HASH_KUNIT_TEST 2413 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2414 depends on KUNIT 2415 default KUNIT_ALL_TESTS 2416 help 2417 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2418 integer (<linux/hash.h>) hash functions on boot. 2419 2420 KUnit tests run during boot and output the results to the debug log 2421 in TAP format (https://testanything.org/). Only useful for kernel devs 2422 running the KUnit test harness, and not intended for inclusion into a 2423 production build. 2424 2425 For more information on KUnit and unit tests in general please refer 2426 to the KUnit documentation in Documentation/dev-tools/kunit/. 2427 2428 This is intended to help people writing architecture-specific 2429 optimized versions. If unsure, say N. 2430 2431config RESOURCE_KUNIT_TEST 2432 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2433 depends on KUNIT 2434 default KUNIT_ALL_TESTS 2435 help 2436 This builds the resource API unit test. 2437 Tests the logic of API provided by resource.c and ioport.h. 2438 For more information on KUnit and unit tests in general please refer 2439 to the KUnit documentation in Documentation/dev-tools/kunit/. 2440 2441 If unsure, say N. 2442 2443config SYSCTL_KUNIT_TEST 2444 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2445 depends on KUNIT 2446 default KUNIT_ALL_TESTS 2447 help 2448 This builds the proc sysctl unit test, which runs on boot. 2449 Tests the API contract and implementation correctness of sysctl. 2450 For more information on KUnit and unit tests in general please refer 2451 to the KUnit documentation in Documentation/dev-tools/kunit/. 2452 2453 If unsure, say N. 2454 2455config LIST_KUNIT_TEST 2456 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2457 depends on KUNIT 2458 default KUNIT_ALL_TESTS 2459 help 2460 This builds the linked list KUnit test suite. 2461 It tests that the API and basic functionality of the list_head type 2462 and associated macros. 2463 2464 KUnit tests run during boot and output the results to the debug log 2465 in TAP format (https://testanything.org/). Only useful for kernel devs 2466 running the KUnit test harness, and not intended for inclusion into a 2467 production build. 2468 2469 For more information on KUnit and unit tests in general please refer 2470 to the KUnit documentation in Documentation/dev-tools/kunit/. 2471 2472 If unsure, say N. 2473 2474config LINEAR_RANGES_TEST 2475 tristate "KUnit test for linear_ranges" 2476 depends on KUNIT 2477 select LINEAR_RANGES 2478 help 2479 This builds the linear_ranges unit test, which runs on boot. 2480 Tests the linear_ranges logic correctness. 2481 For more information on KUnit and unit tests in general please refer 2482 to the KUnit documentation in Documentation/dev-tools/kunit/. 2483 2484 If unsure, say N. 2485 2486config CMDLINE_KUNIT_TEST 2487 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2488 depends on KUNIT 2489 default KUNIT_ALL_TESTS 2490 help 2491 This builds the cmdline API unit test. 2492 Tests the logic of API provided by cmdline.c. 2493 For more information on KUnit and unit tests in general please refer 2494 to the KUnit documentation in Documentation/dev-tools/kunit/. 2495 2496 If unsure, say N. 2497 2498config BITS_TEST 2499 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2500 depends on KUNIT 2501 default KUNIT_ALL_TESTS 2502 help 2503 This builds the bits unit test. 2504 Tests the logic of macros defined in bits.h. 2505 For more information on KUnit and unit tests in general please refer 2506 to the KUnit documentation in Documentation/dev-tools/kunit/. 2507 2508 If unsure, say N. 2509 2510config SLUB_KUNIT_TEST 2511 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2512 depends on SLUB_DEBUG && KUNIT 2513 default KUNIT_ALL_TESTS 2514 help 2515 This builds SLUB allocator unit test. 2516 Tests SLUB cache debugging functionality. 2517 For more information on KUnit and unit tests in general please refer 2518 to the KUnit documentation in Documentation/dev-tools/kunit/. 2519 2520 If unsure, say N. 2521 2522config RATIONAL_KUNIT_TEST 2523 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2524 depends on KUNIT && RATIONAL 2525 default KUNIT_ALL_TESTS 2526 help 2527 This builds the rational math unit test. 2528 For more information on KUnit and unit tests in general please refer 2529 to the KUnit documentation in Documentation/dev-tools/kunit/. 2530 2531 If unsure, say N. 2532 2533config MEMCPY_KUNIT_TEST 2534 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2535 depends on KUNIT 2536 default KUNIT_ALL_TESTS 2537 help 2538 Builds unit tests for memcpy(), memmove(), and memset() functions. 2539 For more information on KUnit and unit tests in general please refer 2540 to the KUnit documentation in Documentation/dev-tools/kunit/. 2541 2542 If unsure, say N. 2543 2544config IS_SIGNED_TYPE_KUNIT_TEST 2545 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2546 depends on KUNIT 2547 default KUNIT_ALL_TESTS 2548 help 2549 Builds unit tests for the is_signed_type() macro. 2550 2551 For more information on KUnit and unit tests in general please refer 2552 to the KUnit documentation in Documentation/dev-tools/kunit/. 2553 2554 If unsure, say N. 2555 2556config OVERFLOW_KUNIT_TEST 2557 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2558 depends on KUNIT 2559 default KUNIT_ALL_TESTS 2560 help 2561 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2562 related functions. 2563 2564 For more information on KUnit and unit tests in general please refer 2565 to the KUnit documentation in Documentation/dev-tools/kunit/. 2566 2567 If unsure, say N. 2568 2569config STACKINIT_KUNIT_TEST 2570 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2571 depends on KUNIT 2572 default KUNIT_ALL_TESTS 2573 help 2574 Test if the kernel is zero-initializing stack variables and 2575 padding. Coverage is controlled by compiler flags, 2576 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2577 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2578 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2579 2580config FORTIFY_KUNIT_TEST 2581 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2582 depends on KUNIT && FORTIFY_SOURCE 2583 default KUNIT_ALL_TESTS 2584 help 2585 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2586 by the str*() and mem*() family of functions. For testing runtime 2587 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2588 2589config HW_BREAKPOINT_KUNIT_TEST 2590 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2591 depends on HAVE_HW_BREAKPOINT 2592 depends on KUNIT=y 2593 default KUNIT_ALL_TESTS 2594 help 2595 Tests for hw_breakpoint constraints accounting. 2596 2597 If unsure, say N. 2598 2599config TEST_UDELAY 2600 tristate "udelay test driver" 2601 help 2602 This builds the "udelay_test" module that helps to make sure 2603 that udelay() is working properly. 2604 2605 If unsure, say N. 2606 2607config TEST_STATIC_KEYS 2608 tristate "Test static keys" 2609 depends on m 2610 help 2611 Test the static key interfaces. 2612 2613 If unsure, say N. 2614 2615config TEST_DYNAMIC_DEBUG 2616 tristate "Test DYNAMIC_DEBUG" 2617 depends on DYNAMIC_DEBUG 2618 help 2619 This module registers a tracer callback to count enabled 2620 pr_debugs in a 'do_debugging' function, then alters their 2621 enablements, calls the function, and compares counts. 2622 2623 If unsure, say N. 2624 2625config TEST_KMOD 2626 tristate "kmod stress tester" 2627 depends on m 2628 depends on NETDEVICES && NET_CORE && INET # for TUN 2629 depends on BLOCK 2630 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2631 select TEST_LKM 2632 select XFS_FS 2633 select TUN 2634 select BTRFS_FS 2635 help 2636 Test the kernel's module loading mechanism: kmod. kmod implements 2637 support to load modules using the Linux kernel's usermode helper. 2638 This test provides a series of tests against kmod. 2639 2640 Although technically you can either build test_kmod as a module or 2641 into the kernel we disallow building it into the kernel since 2642 it stress tests request_module() and this will very likely cause 2643 some issues by taking over precious threads available from other 2644 module load requests, ultimately this could be fatal. 2645 2646 To run tests run: 2647 2648 tools/testing/selftests/kmod/kmod.sh --help 2649 2650 If unsure, say N. 2651 2652config TEST_DEBUG_VIRTUAL 2653 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2654 depends on DEBUG_VIRTUAL 2655 help 2656 Test the kernel's ability to detect incorrect calls to 2657 virt_to_phys() done against the non-linear part of the 2658 kernel's virtual address map. 2659 2660 If unsure, say N. 2661 2662config TEST_MEMCAT_P 2663 tristate "Test memcat_p() helper function" 2664 help 2665 Test the memcat_p() helper for correctly merging two 2666 pointer arrays together. 2667 2668 If unsure, say N. 2669 2670config TEST_LIVEPATCH 2671 tristate "Test livepatching" 2672 default n 2673 depends on DYNAMIC_DEBUG 2674 depends on LIVEPATCH 2675 depends on m 2676 help 2677 Test kernel livepatching features for correctness. The tests will 2678 load test modules that will be livepatched in various scenarios. 2679 2680 To run all the livepatching tests: 2681 2682 make -C tools/testing/selftests TARGETS=livepatch run_tests 2683 2684 Alternatively, individual tests may be invoked: 2685 2686 tools/testing/selftests/livepatch/test-callbacks.sh 2687 tools/testing/selftests/livepatch/test-livepatch.sh 2688 tools/testing/selftests/livepatch/test-shadow-vars.sh 2689 2690 If unsure, say N. 2691 2692config TEST_OBJAGG 2693 tristate "Perform selftest on object aggreration manager" 2694 default n 2695 depends on OBJAGG 2696 help 2697 Enable this option to test object aggregation manager on boot 2698 (or module load). 2699 2700config TEST_MEMINIT 2701 tristate "Test heap/page initialization" 2702 help 2703 Test if the kernel is zero-initializing heap and page allocations. 2704 This can be useful to test init_on_alloc and init_on_free features. 2705 2706 If unsure, say N. 2707 2708config TEST_HMM 2709 tristate "Test HMM (Heterogeneous Memory Management)" 2710 depends on TRANSPARENT_HUGEPAGE 2711 depends on DEVICE_PRIVATE 2712 select HMM_MIRROR 2713 select MMU_NOTIFIER 2714 help 2715 This is a pseudo device driver solely for testing HMM. 2716 Say M here if you want to build the HMM test module. 2717 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2718 2719 If unsure, say N. 2720 2721config TEST_FREE_PAGES 2722 tristate "Test freeing pages" 2723 help 2724 Test that a memory leak does not occur due to a race between 2725 freeing a block of pages and a speculative page reference. 2726 Loading this module is safe if your kernel has the bug fixed. 2727 If the bug is not fixed, it will leak gigabytes of memory and 2728 probably OOM your system. 2729 2730config TEST_FPU 2731 tristate "Test floating point operations in kernel space" 2732 depends on X86 && !KCOV_INSTRUMENT_ALL 2733 help 2734 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2735 which will trigger a sequence of floating point operations. This is used 2736 for self-testing floating point control register setting in 2737 kernel_fpu_begin(). 2738 2739 If unsure, say N. 2740 2741config TEST_CLOCKSOURCE_WATCHDOG 2742 tristate "Test clocksource watchdog in kernel space" 2743 depends on CLOCKSOURCE_WATCHDOG 2744 help 2745 Enable this option to create a kernel module that will trigger 2746 a test of the clocksource watchdog. This module may be loaded 2747 via modprobe or insmod in which case it will run upon being 2748 loaded, or it may be built in, in which case it will run 2749 shortly after boot. 2750 2751 If unsure, say N. 2752 2753endif # RUNTIME_TESTING_MENU 2754 2755config ARCH_USE_MEMTEST 2756 bool 2757 help 2758 An architecture should select this when it uses early_memtest() 2759 during boot process. 2760 2761config MEMTEST 2762 bool "Memtest" 2763 depends on ARCH_USE_MEMTEST 2764 help 2765 This option adds a kernel parameter 'memtest', which allows memtest 2766 to be set and executed. 2767 memtest=0, mean disabled; -- default 2768 memtest=1, mean do 1 test pattern; 2769 ... 2770 memtest=17, mean do 17 test patterns. 2771 If you are unsure how to answer this question, answer N. 2772 2773 2774 2775config HYPERV_TESTING 2776 bool "Microsoft Hyper-V driver testing" 2777 default n 2778 depends on HYPERV && DEBUG_FS 2779 help 2780 Select this option to enable Hyper-V vmbus testing. 2781 2782endmenu # "Kernel Testing and Coverage" 2783 2784menu "Rust hacking" 2785 2786config RUST_DEBUG_ASSERTIONS 2787 bool "Debug assertions" 2788 depends on RUST 2789 help 2790 Enables rustc's `-Cdebug-assertions` codegen option. 2791 2792 This flag lets you turn `cfg(debug_assertions)` conditional 2793 compilation on or off. This can be used to enable extra debugging 2794 code in development but not in production. For example, it controls 2795 the behavior of the standard library's `debug_assert!` macro. 2796 2797 Note that this will apply to all Rust code, including `core`. 2798 2799 If unsure, say N. 2800 2801config RUST_OVERFLOW_CHECKS 2802 bool "Overflow checks" 2803 default y 2804 depends on RUST 2805 help 2806 Enables rustc's `-Coverflow-checks` codegen option. 2807 2808 This flag allows you to control the behavior of runtime integer 2809 overflow. When overflow-checks are enabled, a Rust panic will occur 2810 on overflow. 2811 2812 Note that this will apply to all Rust code, including `core`. 2813 2814 If unsure, say Y. 2815 2816endmenu # "Rust" 2817 2818source "Documentation/Kconfig" 2819 2820endmenu # Kernel hacking 2821