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 315choice 316 prompt "Compressed Debug information" 317 help 318 Compress the resulting debug info. Results in smaller debug info sections, 319 but requires that consumers are able to decompress the results. 320 321 If unsure, choose DEBUG_INFO_COMPRESSED_NONE. 322 323config DEBUG_INFO_COMPRESSED_NONE 324 bool "Don't compress debug information" 325 help 326 Don't compress debug info sections. 327 328config DEBUG_INFO_COMPRESSED_ZLIB 329 bool "Compress debugging information with zlib" 330 depends on $(cc-option,-gz=zlib) 331 depends on $(ld-option,--compress-debug-sections=zlib) 332 help 333 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 334 5.0+, binutils 2.26+, and zlib. 335 336 Users of dpkg-deb via scripts/package/builddeb may find an increase in 337 size of their debug .deb packages with this config set, due to the 338 debug info being compressed with zlib, then the object files being 339 recompressed with a different compression scheme. But this is still 340 preferable to setting $KDEB_COMPRESS to "none" which would be even 341 larger. 342 343config DEBUG_INFO_COMPRESSED_ZSTD 344 bool "Compress debugging information with zstd" 345 depends on $(cc-option,-gz=zstd) 346 depends on $(ld-option,--compress-debug-sections=zstd) 347 help 348 Compress the debug information using zstd. This may provide better 349 compression than zlib, for about the same time costs, but requires newer 350 toolchain support. Requires GCC 13.0+ or Clang 16.0+, binutils 2.40+, and 351 zstd. 352 353endchoice # "Compressed Debug information" 354 355config DEBUG_INFO_SPLIT 356 bool "Produce split debuginfo in .dwo files" 357 depends on $(cc-option,-gsplit-dwarf) 358 # RISC-V linker relaxation + -gsplit-dwarf has issues with LLVM and GCC 359 # prior to 12.x: 360 # https://github.com/llvm/llvm-project/issues/56642 361 # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99090 362 depends on !RISCV || GCC_VERSION >= 120000 363 help 364 Generate debug info into separate .dwo files. This significantly 365 reduces the build directory size for builds with DEBUG_INFO, 366 because it stores the information only once on disk in .dwo 367 files instead of multiple times in object files and executables. 368 In addition the debug information is also compressed. 369 370 Requires recent gcc (4.7+) and recent gdb/binutils. 371 Any tool that packages or reads debug information would need 372 to know about the .dwo files and include them. 373 Incompatible with older versions of ccache. 374 375config DEBUG_INFO_BTF 376 bool "Generate BTF typeinfo" 377 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 378 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 379 depends on BPF_SYSCALL 380 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 381 help 382 Generate deduplicated BTF type information from DWARF debug info. 383 Turning this on expects presence of pahole tool, which will convert 384 DWARF type info into equivalent deduplicated BTF type info. 385 386config PAHOLE_HAS_SPLIT_BTF 387 def_bool PAHOLE_VERSION >= 119 388 389config PAHOLE_HAS_BTF_TAG 390 def_bool PAHOLE_VERSION >= 123 391 depends on CC_IS_CLANG 392 help 393 Decide whether pahole emits btf_tag attributes (btf_type_tag and 394 btf_decl_tag) or not. Currently only clang compiler implements 395 these attributes, so make the config depend on CC_IS_CLANG. 396 397config PAHOLE_HAS_LANG_EXCLUDE 398 def_bool PAHOLE_VERSION >= 124 399 help 400 Support for the --lang_exclude flag which makes pahole exclude 401 compilation units from the supplied language. Used in Kbuild to 402 omit Rust CUs which are not supported in version 1.24 of pahole, 403 otherwise it would emit malformed kernel and module binaries when 404 using DEBUG_INFO_BTF_MODULES. 405 406config DEBUG_INFO_BTF_MODULES 407 def_bool y 408 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 409 help 410 Generate compact split BTF type information for kernel modules. 411 412config MODULE_ALLOW_BTF_MISMATCH 413 bool "Allow loading modules with non-matching BTF type info" 414 depends on DEBUG_INFO_BTF_MODULES 415 help 416 For modules whose split BTF does not match vmlinux, load without 417 BTF rather than refusing to load. The default behavior with 418 module BTF enabled is to reject modules with such mismatches; 419 this option will still load module BTF where possible but ignore 420 it when a mismatch is found. 421 422config GDB_SCRIPTS 423 bool "Provide GDB scripts for kernel debugging" 424 help 425 This creates the required links to GDB helper scripts in the 426 build directory. If you load vmlinux into gdb, the helper 427 scripts will be automatically imported by gdb as well, and 428 additional functions are available to analyze a Linux kernel 429 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 430 for further details. 431 432endif # DEBUG_INFO 433 434config FRAME_WARN 435 int "Warn for stack frames larger than" 436 range 0 8192 437 default 0 if KMSAN 438 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 439 default 2048 if PARISC 440 default 1536 if (!64BIT && XTENSA) 441 default 1280 if KASAN && !64BIT 442 default 1024 if !64BIT 443 default 2048 if 64BIT 444 help 445 Tell the compiler to warn at build time for stack frames larger than this. 446 Setting this too low will cause a lot of warnings. 447 Setting it to 0 disables the warning. 448 449config STRIP_ASM_SYMS 450 bool "Strip assembler-generated symbols during link" 451 default n 452 help 453 Strip internal assembler-generated symbols during a link (symbols 454 that look like '.Lxxx') so they don't pollute the output of 455 get_wchan() and suchlike. 456 457config READABLE_ASM 458 bool "Generate readable assembler code" 459 depends on DEBUG_KERNEL 460 depends on CC_IS_GCC 461 help 462 Disable some compiler optimizations that tend to generate human unreadable 463 assembler output. This may make the kernel slightly slower, but it helps 464 to keep kernel developers who have to stare a lot at assembler listings 465 sane. 466 467config HEADERS_INSTALL 468 bool "Install uapi headers to usr/include" 469 depends on !UML 470 help 471 This option will install uapi headers (headers exported to user-space) 472 into the usr/include directory for use during the kernel build. 473 This is unneeded for building the kernel itself, but needed for some 474 user-space program samples. It is also needed by some features such 475 as uapi header sanity checks. 476 477config DEBUG_SECTION_MISMATCH 478 bool "Enable full Section mismatch analysis" 479 depends on CC_IS_GCC 480 help 481 The section mismatch analysis checks if there are illegal 482 references from one section to another section. 483 During linktime or runtime, some sections are dropped; 484 any use of code/data previously in these sections would 485 most likely result in an oops. 486 In the code, functions and variables are annotated with 487 __init,, etc. (see the full list in include/linux/init.h), 488 which results in the code/data being placed in specific sections. 489 The section mismatch analysis is always performed after a full 490 kernel build, and enabling this option causes the following 491 additional step to occur: 492 - Add the option -fno-inline-functions-called-once to gcc commands. 493 When inlining a function annotated with __init in a non-init 494 function, we would lose the section information and thus 495 the analysis would not catch the illegal reference. 496 This option tells gcc to inline less (but it does result in 497 a larger kernel). 498 499config SECTION_MISMATCH_WARN_ONLY 500 bool "Make section mismatch errors non-fatal" 501 default y 502 help 503 If you say N here, the build process will fail if there are any 504 section mismatch, instead of just throwing warnings. 505 506 If unsure, say Y. 507 508config DEBUG_FORCE_FUNCTION_ALIGN_64B 509 bool "Force all function address 64B aligned" 510 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390) 511 select FUNCTION_ALIGNMENT_64B 512 help 513 There are cases that a commit from one domain changes the function 514 address alignment of other domains, and cause magic performance 515 bump (regression or improvement). Enable this option will help to 516 verify if the bump is caused by function alignment changes, while 517 it will slightly increase the kernel size and affect icache usage. 518 519 It is mainly for debug and performance tuning use. 520 521# 522# Select this config option from the architecture Kconfig, if it 523# is preferred to always offer frame pointers as a config 524# option on the architecture (regardless of KERNEL_DEBUG): 525# 526config ARCH_WANT_FRAME_POINTERS 527 bool 528 529config FRAME_POINTER 530 bool "Compile the kernel with frame pointers" 531 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 532 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 533 help 534 If you say Y here the resulting kernel image will be slightly 535 larger and slower, but it gives very useful debugging information 536 in case of kernel bugs. (precise oopses/stacktraces/warnings) 537 538config OBJTOOL 539 bool 540 541config STACK_VALIDATION 542 bool "Compile-time stack metadata validation" 543 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 544 select OBJTOOL 545 default n 546 help 547 Validate frame pointer rules at compile-time. This helps ensure that 548 runtime stack traces are more reliable. 549 550 For more information, see 551 tools/objtool/Documentation/objtool.txt. 552 553config NOINSTR_VALIDATION 554 bool 555 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 556 select OBJTOOL 557 default y 558 559config VMLINUX_MAP 560 bool "Generate vmlinux.map file when linking" 561 depends on EXPERT 562 help 563 Selecting this option will pass "-Map=vmlinux.map" to ld 564 when linking vmlinux. That file can be useful for verifying 565 and debugging magic section games, and for seeing which 566 pieces of code get eliminated with 567 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 568 569config DEBUG_FORCE_WEAK_PER_CPU 570 bool "Force weak per-cpu definitions" 571 depends on DEBUG_KERNEL 572 help 573 s390 and alpha require percpu variables in modules to be 574 defined weak to work around addressing range issue which 575 puts the following two restrictions on percpu variable 576 definitions. 577 578 1. percpu symbols must be unique whether static or not 579 2. percpu variables can't be defined inside a function 580 581 To ensure that generic code follows the above rules, this 582 option forces all percpu variables to be defined as weak. 583 584endmenu # "Compiler options" 585 586menu "Generic Kernel Debugging Instruments" 587 588config MAGIC_SYSRQ 589 bool "Magic SysRq key" 590 depends on !UML 591 help 592 If you say Y here, you will have some control over the system even 593 if the system crashes for example during kernel debugging (e.g., you 594 will be able to flush the buffer cache to disk, reboot the system 595 immediately or dump some status information). This is accomplished 596 by pressing various keys while holding SysRq (Alt+PrintScreen). It 597 also works on a serial console (on PC hardware at least), if you 598 send a BREAK and then within 5 seconds a command keypress. The 599 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 600 Don't say Y unless you really know what this hack does. 601 602config MAGIC_SYSRQ_DEFAULT_ENABLE 603 hex "Enable magic SysRq key functions by default" 604 depends on MAGIC_SYSRQ 605 default 0x1 606 help 607 Specifies which SysRq key functions are enabled by default. 608 This may be set to 1 or 0 to enable or disable them all, or 609 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 610 611config MAGIC_SYSRQ_SERIAL 612 bool "Enable magic SysRq key over serial" 613 depends on MAGIC_SYSRQ 614 default y 615 help 616 Many embedded boards have a disconnected TTL level serial which can 617 generate some garbage that can lead to spurious false sysrq detects. 618 This option allows you to decide whether you want to enable the 619 magic SysRq key. 620 621config MAGIC_SYSRQ_SERIAL_SEQUENCE 622 string "Char sequence that enables magic SysRq over serial" 623 depends on MAGIC_SYSRQ_SERIAL 624 default "" 625 help 626 Specifies a sequence of characters that can follow BREAK to enable 627 SysRq on a serial console. 628 629 If unsure, leave an empty string and the option will not be enabled. 630 631config DEBUG_FS 632 bool "Debug Filesystem" 633 help 634 debugfs is a virtual file system that kernel developers use to put 635 debugging files into. Enable this option to be able to read and 636 write to these files. 637 638 For detailed documentation on the debugfs API, see 639 Documentation/filesystems/. 640 641 If unsure, say N. 642 643choice 644 prompt "Debugfs default access" 645 depends on DEBUG_FS 646 default DEBUG_FS_ALLOW_ALL 647 help 648 This selects the default access restrictions for debugfs. 649 It can be overridden with kernel command line option 650 debugfs=[on,no-mount,off]. The restrictions apply for API access 651 and filesystem registration. 652 653config DEBUG_FS_ALLOW_ALL 654 bool "Access normal" 655 help 656 No restrictions apply. Both API and filesystem registration 657 is on. This is the normal default operation. 658 659config DEBUG_FS_DISALLOW_MOUNT 660 bool "Do not register debugfs as filesystem" 661 help 662 The API is open but filesystem is not loaded. Clients can still do 663 their work and read with debug tools that do not need 664 debugfs filesystem. 665 666config DEBUG_FS_ALLOW_NONE 667 bool "No access" 668 help 669 Access is off. Clients get -PERM when trying to create nodes in 670 debugfs tree and debugfs is not registered as a filesystem. 671 Client can then back-off or continue without debugfs access. 672 673endchoice 674 675source "lib/Kconfig.kgdb" 676source "lib/Kconfig.ubsan" 677source "lib/Kconfig.kcsan" 678 679endmenu 680 681menu "Networking Debugging" 682 683source "net/Kconfig.debug" 684 685endmenu # "Networking Debugging" 686 687menu "Memory Debugging" 688 689source "mm/Kconfig.debug" 690 691config DEBUG_OBJECTS 692 bool "Debug object operations" 693 depends on DEBUG_KERNEL 694 help 695 If you say Y here, additional code will be inserted into the 696 kernel to track the life time of various objects and validate 697 the operations on those objects. 698 699config DEBUG_OBJECTS_SELFTEST 700 bool "Debug objects selftest" 701 depends on DEBUG_OBJECTS 702 help 703 This enables the selftest of the object debug code. 704 705config DEBUG_OBJECTS_FREE 706 bool "Debug objects in freed memory" 707 depends on DEBUG_OBJECTS 708 help 709 This enables checks whether a k/v free operation frees an area 710 which contains an object which has not been deactivated 711 properly. This can make kmalloc/kfree-intensive workloads 712 much slower. 713 714config DEBUG_OBJECTS_TIMERS 715 bool "Debug timer objects" 716 depends on DEBUG_OBJECTS 717 help 718 If you say Y here, additional code will be inserted into the 719 timer routines to track the life time of timer objects and 720 validate the timer operations. 721 722config DEBUG_OBJECTS_WORK 723 bool "Debug work objects" 724 depends on DEBUG_OBJECTS 725 help 726 If you say Y here, additional code will be inserted into the 727 work queue routines to track the life time of work objects and 728 validate the work operations. 729 730config DEBUG_OBJECTS_RCU_HEAD 731 bool "Debug RCU callbacks objects" 732 depends on DEBUG_OBJECTS 733 help 734 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 735 736config DEBUG_OBJECTS_PERCPU_COUNTER 737 bool "Debug percpu counter objects" 738 depends on DEBUG_OBJECTS 739 help 740 If you say Y here, additional code will be inserted into the 741 percpu counter routines to track the life time of percpu counter 742 objects and validate the percpu counter operations. 743 744config DEBUG_OBJECTS_ENABLE_DEFAULT 745 int "debug_objects bootup default value (0-1)" 746 range 0 1 747 default "1" 748 depends on DEBUG_OBJECTS 749 help 750 Debug objects boot parameter default value 751 752config SHRINKER_DEBUG 753 bool "Enable shrinker debugging support" 754 depends on DEBUG_FS 755 help 756 Say Y to enable the shrinker debugfs interface which provides 757 visibility into the kernel memory shrinkers subsystem. 758 Disable it to avoid an extra memory footprint. 759 760config DEBUG_STACK_USAGE 761 bool "Stack utilization instrumentation" 762 depends on DEBUG_KERNEL 763 help 764 Enables the display of the minimum amount of free stack which each 765 task has ever had available in the sysrq-T and sysrq-P debug output. 766 767 This option will slow down process creation somewhat. 768 769config SCHED_STACK_END_CHECK 770 bool "Detect stack corruption on calls to schedule()" 771 depends on DEBUG_KERNEL 772 default n 773 help 774 This option checks for a stack overrun on calls to schedule(). 775 If the stack end location is found to be over written always panic as 776 the content of the corrupted region can no longer be trusted. 777 This is to ensure no erroneous behaviour occurs which could result in 778 data corruption or a sporadic crash at a later stage once the region 779 is examined. The runtime overhead introduced is minimal. 780 781config ARCH_HAS_DEBUG_VM_PGTABLE 782 bool 783 help 784 An architecture should select this when it can successfully 785 build and run DEBUG_VM_PGTABLE. 786 787config DEBUG_VM_IRQSOFF 788 def_bool DEBUG_VM && !PREEMPT_RT 789 790config DEBUG_VM 791 bool "Debug VM" 792 depends on DEBUG_KERNEL 793 help 794 Enable this to turn on extended checks in the virtual-memory system 795 that may impact performance. 796 797 If unsure, say N. 798 799config DEBUG_VM_SHOOT_LAZIES 800 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation" 801 depends on DEBUG_VM 802 depends on MMU_LAZY_TLB_SHOOTDOWN 803 help 804 Enable additional IPIs that ensure lazy tlb mm references are removed 805 before the mm is freed. 806 807 If unsure, say N. 808 809config DEBUG_VM_MAPLE_TREE 810 bool "Debug VM maple trees" 811 depends on DEBUG_VM 812 select DEBUG_MAPLE_TREE 813 help 814 Enable VM maple tree debugging information and extra validations. 815 816 If unsure, say N. 817 818config DEBUG_VM_RB 819 bool "Debug VM red-black trees" 820 depends on DEBUG_VM 821 help 822 Enable VM red-black tree debugging information and extra validations. 823 824 If unsure, say N. 825 826config DEBUG_VM_PGFLAGS 827 bool "Debug page-flags operations" 828 depends on DEBUG_VM 829 help 830 Enables extra validation on page flags operations. 831 832 If unsure, say N. 833 834config DEBUG_VM_PGTABLE 835 bool "Debug arch page table for semantics compliance" 836 depends on MMU 837 depends on ARCH_HAS_DEBUG_VM_PGTABLE 838 default y if DEBUG_VM 839 help 840 This option provides a debug method which can be used to test 841 architecture page table helper functions on various platforms in 842 verifying if they comply with expected generic MM semantics. This 843 will help architecture code in making sure that any changes or 844 new additions of these helpers still conform to expected 845 semantics of the generic MM. Platforms will have to opt in for 846 this through ARCH_HAS_DEBUG_VM_PGTABLE. 847 848 If unsure, say N. 849 850config ARCH_HAS_DEBUG_VIRTUAL 851 bool 852 853config DEBUG_VIRTUAL 854 bool "Debug VM translations" 855 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 856 help 857 Enable some costly sanity checks in virtual to page code. This can 858 catch mistakes with virt_to_page() and friends. 859 860 If unsure, say N. 861 862config DEBUG_NOMMU_REGIONS 863 bool "Debug the global anon/private NOMMU mapping region tree" 864 depends on DEBUG_KERNEL && !MMU 865 help 866 This option causes the global tree of anonymous and private mapping 867 regions to be regularly checked for invalid topology. 868 869config DEBUG_MEMORY_INIT 870 bool "Debug memory initialisation" if EXPERT 871 default !EXPERT 872 help 873 Enable this for additional checks during memory initialisation. 874 The sanity checks verify aspects of the VM such as the memory model 875 and other information provided by the architecture. Verbose 876 information will be printed at KERN_DEBUG loglevel depending 877 on the mminit_loglevel= command-line option. 878 879 If unsure, say Y 880 881config MEMORY_NOTIFIER_ERROR_INJECT 882 tristate "Memory hotplug notifier error injection module" 883 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 884 help 885 This option provides the ability to inject artificial errors to 886 memory hotplug notifier chain callbacks. It is controlled through 887 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 888 889 If the notifier call chain should be failed with some events 890 notified, write the error code to "actions/<notifier event>/error". 891 892 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 893 894 # cd /sys/kernel/debug/notifier-error-inject/memory 895 # echo -12 > actions/MEM_GOING_OFFLINE/error 896 # echo offline > /sys/devices/system/memory/memoryXXX/state 897 bash: echo: write error: Cannot allocate memory 898 899 To compile this code as a module, choose M here: the module will 900 be called memory-notifier-error-inject. 901 902 If unsure, say N. 903 904config DEBUG_PER_CPU_MAPS 905 bool "Debug access to per_cpu maps" 906 depends on DEBUG_KERNEL 907 depends on SMP 908 help 909 Say Y to verify that the per_cpu map being accessed has 910 been set up. This adds a fair amount of code to kernel memory 911 and decreases performance. 912 913 Say N if unsure. 914 915config DEBUG_KMAP_LOCAL 916 bool "Debug kmap_local temporary mappings" 917 depends on DEBUG_KERNEL && KMAP_LOCAL 918 help 919 This option enables additional error checking for the kmap_local 920 infrastructure. Disable for production use. 921 922config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 923 bool 924 925config DEBUG_KMAP_LOCAL_FORCE_MAP 926 bool "Enforce kmap_local temporary mappings" 927 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 928 select KMAP_LOCAL 929 select DEBUG_KMAP_LOCAL 930 help 931 This option enforces temporary mappings through the kmap_local 932 mechanism for non-highmem pages and on non-highmem systems. 933 Disable this for production systems! 934 935config DEBUG_HIGHMEM 936 bool "Highmem debugging" 937 depends on DEBUG_KERNEL && HIGHMEM 938 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 939 select DEBUG_KMAP_LOCAL 940 help 941 This option enables additional error checking for high memory 942 systems. Disable for production systems. 943 944config HAVE_DEBUG_STACKOVERFLOW 945 bool 946 947config DEBUG_STACKOVERFLOW 948 bool "Check for stack overflows" 949 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 950 help 951 Say Y here if you want to check for overflows of kernel, IRQ 952 and exception stacks (if your architecture uses them). This 953 option will show detailed messages if free stack space drops 954 below a certain limit. 955 956 These kinds of bugs usually occur when call-chains in the 957 kernel get too deep, especially when interrupts are 958 involved. 959 960 Use this in cases where you see apparently random memory 961 corruption, especially if it appears in 'struct thread_info' 962 963 If in doubt, say "N". 964 965source "lib/Kconfig.kasan" 966source "lib/Kconfig.kfence" 967source "lib/Kconfig.kmsan" 968 969endmenu # "Memory Debugging" 970 971config DEBUG_SHIRQ 972 bool "Debug shared IRQ handlers" 973 depends on DEBUG_KERNEL 974 help 975 Enable this to generate a spurious interrupt just before a shared 976 interrupt handler is deregistered (generating one when registering 977 is currently disabled). Drivers need to handle this correctly. Some 978 don't and need to be caught. 979 980menu "Debug Oops, Lockups and Hangs" 981 982config PANIC_ON_OOPS 983 bool "Panic on Oops" 984 help 985 Say Y here to enable the kernel to panic when it oopses. This 986 has the same effect as setting oops=panic on the kernel command 987 line. 988 989 This feature is useful to ensure that the kernel does not do 990 anything erroneous after an oops which could result in data 991 corruption or other issues. 992 993 Say N if unsure. 994 995config PANIC_ON_OOPS_VALUE 996 int 997 range 0 1 998 default 0 if !PANIC_ON_OOPS 999 default 1 if PANIC_ON_OOPS 1000 1001config PANIC_TIMEOUT 1002 int "panic timeout" 1003 default 0 1004 help 1005 Set the timeout value (in seconds) until a reboot occurs when 1006 the kernel panics. If n = 0, then we wait forever. A timeout 1007 value n > 0 will wait n seconds before rebooting, while a timeout 1008 value n < 0 will reboot immediately. 1009 1010config LOCKUP_DETECTOR 1011 bool 1012 1013config SOFTLOCKUP_DETECTOR 1014 bool "Detect Soft Lockups" 1015 depends on DEBUG_KERNEL && !S390 1016 select LOCKUP_DETECTOR 1017 help 1018 Say Y here to enable the kernel to act as a watchdog to detect 1019 soft lockups. 1020 1021 Softlockups are bugs that cause the kernel to loop in kernel 1022 mode for more than 20 seconds, without giving other tasks a 1023 chance to run. The current stack trace is displayed upon 1024 detection and the system will stay locked up. 1025 1026config BOOTPARAM_SOFTLOCKUP_PANIC 1027 bool "Panic (Reboot) On Soft Lockups" 1028 depends on SOFTLOCKUP_DETECTOR 1029 help 1030 Say Y here to enable the kernel to panic on "soft lockups", 1031 which are bugs that cause the kernel to loop in kernel 1032 mode for more than 20 seconds (configurable using the watchdog_thresh 1033 sysctl), without giving other tasks a chance to run. 1034 1035 The panic can be used in combination with panic_timeout, 1036 to cause the system to reboot automatically after a 1037 lockup has been detected. This feature is useful for 1038 high-availability systems that have uptime guarantees and 1039 where a lockup must be resolved ASAP. 1040 1041 Say N if unsure. 1042 1043config HAVE_HARDLOCKUP_DETECTOR_BUDDY 1044 bool 1045 depends on SMP 1046 default y 1047 1048# 1049# Global switch whether to build a hardlockup detector at all. It is available 1050# only when the architecture supports at least one implementation. There are 1051# two exceptions. The hardlockup detector is never enabled on: 1052# 1053# s390: it reported many false positives there 1054# 1055# sparc64: has a custom implementation which is not using the common 1056# hardlockup command line options and sysctl interface. 1057# 1058config HARDLOCKUP_DETECTOR 1059 bool "Detect Hard Lockups" 1060 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64 1061 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH 1062 imply HARDLOCKUP_DETECTOR_PERF 1063 imply HARDLOCKUP_DETECTOR_BUDDY 1064 imply HARDLOCKUP_DETECTOR_ARCH 1065 select LOCKUP_DETECTOR 1066 1067 help 1068 Say Y here to enable the kernel to act as a watchdog to detect 1069 hard lockups. 1070 1071 Hardlockups are bugs that cause the CPU to loop in kernel mode 1072 for more than 10 seconds, without letting other interrupts have a 1073 chance to run. The current stack trace is displayed upon detection 1074 and the system will stay locked up. 1075 1076# 1077# Note that arch-specific variants are always preferred. 1078# 1079config HARDLOCKUP_DETECTOR_PREFER_BUDDY 1080 bool "Prefer the buddy CPU hardlockup detector" 1081 depends on HARDLOCKUP_DETECTOR 1082 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY 1083 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1084 help 1085 Say Y here to prefer the buddy hardlockup detector over the perf one. 1086 1087 With the buddy detector, each CPU uses its softlockup hrtimer 1088 to check that the next CPU is processing hrtimer interrupts by 1089 verifying that a counter is increasing. 1090 1091 This hardlockup detector is useful on systems that don't have 1092 an arch-specific hardlockup detector or if resources needed 1093 for the hardlockup detector are better used for other things. 1094 1095config HARDLOCKUP_DETECTOR_PERF 1096 bool 1097 depends on HARDLOCKUP_DETECTOR 1098 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY 1099 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1100 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1101 1102config HARDLOCKUP_DETECTOR_BUDDY 1103 bool 1104 depends on HARDLOCKUP_DETECTOR 1105 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY 1106 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY 1107 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1108 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1109 1110config HARDLOCKUP_DETECTOR_ARCH 1111 bool 1112 depends on HARDLOCKUP_DETECTOR 1113 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH 1114 help 1115 The arch-specific implementation of the hardlockup detector will 1116 be used. 1117 1118# 1119# Both the "perf" and "buddy" hardlockup detectors count hrtimer 1120# interrupts. This config enables functions managing this common code. 1121# 1122config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1123 bool 1124 select SOFTLOCKUP_DETECTOR 1125 1126# 1127# Enables a timestamp based low pass filter to compensate for perf based 1128# hard lockup detection which runs too fast due to turbo modes. 1129# 1130config HARDLOCKUP_CHECK_TIMESTAMP 1131 bool 1132 1133config BOOTPARAM_HARDLOCKUP_PANIC 1134 bool "Panic (Reboot) On Hard Lockups" 1135 depends on HARDLOCKUP_DETECTOR 1136 help 1137 Say Y here to enable the kernel to panic on "hard lockups", 1138 which are bugs that cause the kernel to loop in kernel 1139 mode with interrupts disabled for more than 10 seconds (configurable 1140 using the watchdog_thresh sysctl). 1141 1142 Say N if unsure. 1143 1144config DETECT_HUNG_TASK 1145 bool "Detect Hung Tasks" 1146 depends on DEBUG_KERNEL 1147 default SOFTLOCKUP_DETECTOR 1148 help 1149 Say Y here to enable the kernel to detect "hung tasks", 1150 which are bugs that cause the task to be stuck in 1151 uninterruptible "D" state indefinitely. 1152 1153 When a hung task is detected, the kernel will print the 1154 current stack trace (which you should report), but the 1155 task will stay in uninterruptible state. If lockdep is 1156 enabled then all held locks will also be reported. This 1157 feature has negligible overhead. 1158 1159config DEFAULT_HUNG_TASK_TIMEOUT 1160 int "Default timeout for hung task detection (in seconds)" 1161 depends on DETECT_HUNG_TASK 1162 default 120 1163 help 1164 This option controls the default timeout (in seconds) used 1165 to determine when a task has become non-responsive and should 1166 be considered hung. 1167 1168 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1169 sysctl or by writing a value to 1170 /proc/sys/kernel/hung_task_timeout_secs. 1171 1172 A timeout of 0 disables the check. The default is two minutes. 1173 Keeping the default should be fine in most cases. 1174 1175config BOOTPARAM_HUNG_TASK_PANIC 1176 bool "Panic (Reboot) On Hung Tasks" 1177 depends on DETECT_HUNG_TASK 1178 help 1179 Say Y here to enable the kernel to panic on "hung tasks", 1180 which are bugs that cause the kernel to leave a task stuck 1181 in uninterruptible "D" state. 1182 1183 The panic can be used in combination with panic_timeout, 1184 to cause the system to reboot automatically after a 1185 hung task has been detected. This feature is useful for 1186 high-availability systems that have uptime guarantees and 1187 where a hung tasks must be resolved ASAP. 1188 1189 Say N if unsure. 1190 1191config WQ_WATCHDOG 1192 bool "Detect Workqueue Stalls" 1193 depends on DEBUG_KERNEL 1194 help 1195 Say Y here to enable stall detection on workqueues. If a 1196 worker pool doesn't make forward progress on a pending work 1197 item for over a given amount of time, 30s by default, a 1198 warning message is printed along with dump of workqueue 1199 state. This can be configured through kernel parameter 1200 "workqueue.watchdog_thresh" and its sysfs counterpart. 1201 1202config WQ_CPU_INTENSIVE_REPORT 1203 bool "Report per-cpu work items which hog CPU for too long" 1204 depends on DEBUG_KERNEL 1205 help 1206 Say Y here to enable reporting of concurrency-managed per-cpu work 1207 items that hog CPUs for longer than 1208 workqueue.cpu_intensive_thresh_us. Workqueue automatically 1209 detects and excludes them from concurrency management to prevent 1210 them from stalling other per-cpu work items. Occassional 1211 triggering may not necessarily indicate a problem. Repeated 1212 triggering likely indicates that the work item should be switched 1213 to use an unbound workqueue. 1214 1215config TEST_LOCKUP 1216 tristate "Test module to generate lockups" 1217 depends on m 1218 help 1219 This builds the "test_lockup" module that helps to make sure 1220 that watchdogs and lockup detectors are working properly. 1221 1222 Depending on module parameters it could emulate soft or hard 1223 lockup, "hung task", or locking arbitrary lock for a long time. 1224 Also it could generate series of lockups with cooling-down periods. 1225 1226 If unsure, say N. 1227 1228endmenu # "Debug lockups and hangs" 1229 1230menu "Scheduler Debugging" 1231 1232config SCHED_DEBUG 1233 bool "Collect scheduler debugging info" 1234 depends on DEBUG_KERNEL && DEBUG_FS 1235 default y 1236 help 1237 If you say Y here, the /sys/kernel/debug/sched file will be provided 1238 that can help debug the scheduler. The runtime overhead of this 1239 option is minimal. 1240 1241config SCHED_INFO 1242 bool 1243 default n 1244 1245config SCHEDSTATS 1246 bool "Collect scheduler statistics" 1247 depends on DEBUG_KERNEL && PROC_FS 1248 select SCHED_INFO 1249 help 1250 If you say Y here, additional code will be inserted into the 1251 scheduler and related routines to collect statistics about 1252 scheduler behavior and provide them in /proc/schedstat. These 1253 stats may be useful for both tuning and debugging the scheduler 1254 If you aren't debugging the scheduler or trying to tune a specific 1255 application, you can say N to avoid the very slight overhead 1256 this adds. 1257 1258endmenu 1259 1260config DEBUG_TIMEKEEPING 1261 bool "Enable extra timekeeping sanity checking" 1262 help 1263 This option will enable additional timekeeping sanity checks 1264 which may be helpful when diagnosing issues where timekeeping 1265 problems are suspected. 1266 1267 This may include checks in the timekeeping hotpaths, so this 1268 option may have a (very small) performance impact to some 1269 workloads. 1270 1271 If unsure, say N. 1272 1273config DEBUG_PREEMPT 1274 bool "Debug preemptible kernel" 1275 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1276 help 1277 If you say Y here then the kernel will use a debug variant of the 1278 commonly used smp_processor_id() function and will print warnings 1279 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1280 will detect preemption count underflows. 1281 1282 This option has potential to introduce high runtime overhead, 1283 depending on workload as it triggers debugging routines for each 1284 this_cpu operation. It should only be used for debugging purposes. 1285 1286menu "Lock Debugging (spinlocks, mutexes, etc...)" 1287 1288config LOCK_DEBUGGING_SUPPORT 1289 bool 1290 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1291 default y 1292 1293config PROVE_LOCKING 1294 bool "Lock debugging: prove locking correctness" 1295 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1296 select LOCKDEP 1297 select DEBUG_SPINLOCK 1298 select DEBUG_MUTEXES if !PREEMPT_RT 1299 select DEBUG_RT_MUTEXES if RT_MUTEXES 1300 select DEBUG_RWSEMS 1301 select DEBUG_WW_MUTEX_SLOWPATH 1302 select DEBUG_LOCK_ALLOC 1303 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1304 select TRACE_IRQFLAGS 1305 default n 1306 help 1307 This feature enables the kernel to prove that all locking 1308 that occurs in the kernel runtime is mathematically 1309 correct: that under no circumstance could an arbitrary (and 1310 not yet triggered) combination of observed locking 1311 sequences (on an arbitrary number of CPUs, running an 1312 arbitrary number of tasks and interrupt contexts) cause a 1313 deadlock. 1314 1315 In short, this feature enables the kernel to report locking 1316 related deadlocks before they actually occur. 1317 1318 The proof does not depend on how hard and complex a 1319 deadlock scenario would be to trigger: how many 1320 participant CPUs, tasks and irq-contexts would be needed 1321 for it to trigger. The proof also does not depend on 1322 timing: if a race and a resulting deadlock is possible 1323 theoretically (no matter how unlikely the race scenario 1324 is), it will be proven so and will immediately be 1325 reported by the kernel (once the event is observed that 1326 makes the deadlock theoretically possible). 1327 1328 If a deadlock is impossible (i.e. the locking rules, as 1329 observed by the kernel, are mathematically correct), the 1330 kernel reports nothing. 1331 1332 NOTE: this feature can also be enabled for rwlocks, mutexes 1333 and rwsems - in which case all dependencies between these 1334 different locking variants are observed and mapped too, and 1335 the proof of observed correctness is also maintained for an 1336 arbitrary combination of these separate locking variants. 1337 1338 For more details, see Documentation/locking/lockdep-design.rst. 1339 1340config PROVE_RAW_LOCK_NESTING 1341 bool "Enable raw_spinlock - spinlock nesting checks" 1342 depends on PROVE_LOCKING 1343 default n 1344 help 1345 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1346 that the lock nesting rules for PREEMPT_RT enabled kernels are 1347 not violated. 1348 1349 NOTE: There are known nesting problems. So if you enable this 1350 option expect lockdep splats until these problems have been fully 1351 addressed which is work in progress. This config switch allows to 1352 identify and analyze these problems. It will be removed and the 1353 check permanently enabled once the main issues have been fixed. 1354 1355 If unsure, select N. 1356 1357config LOCK_STAT 1358 bool "Lock usage statistics" 1359 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1360 select LOCKDEP 1361 select DEBUG_SPINLOCK 1362 select DEBUG_MUTEXES if !PREEMPT_RT 1363 select DEBUG_RT_MUTEXES if RT_MUTEXES 1364 select DEBUG_LOCK_ALLOC 1365 default n 1366 help 1367 This feature enables tracking lock contention points 1368 1369 For more details, see Documentation/locking/lockstat.rst 1370 1371 This also enables lock events required by "perf lock", 1372 subcommand of perf. 1373 If you want to use "perf lock", you also need to turn on 1374 CONFIG_EVENT_TRACING. 1375 1376 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1377 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1378 1379config DEBUG_RT_MUTEXES 1380 bool "RT Mutex debugging, deadlock detection" 1381 depends on DEBUG_KERNEL && RT_MUTEXES 1382 help 1383 This allows rt mutex semantics violations and rt mutex related 1384 deadlocks (lockups) to be detected and reported automatically. 1385 1386config DEBUG_SPINLOCK 1387 bool "Spinlock and rw-lock debugging: basic checks" 1388 depends on DEBUG_KERNEL 1389 select UNINLINE_SPIN_UNLOCK 1390 help 1391 Say Y here and build SMP to catch missing spinlock initialization 1392 and certain other kinds of spinlock errors commonly made. This is 1393 best used in conjunction with the NMI watchdog so that spinlock 1394 deadlocks are also debuggable. 1395 1396config DEBUG_MUTEXES 1397 bool "Mutex debugging: basic checks" 1398 depends on DEBUG_KERNEL && !PREEMPT_RT 1399 help 1400 This feature allows mutex semantics violations to be detected and 1401 reported. 1402 1403config DEBUG_WW_MUTEX_SLOWPATH 1404 bool "Wait/wound mutex debugging: Slowpath testing" 1405 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1406 select DEBUG_LOCK_ALLOC 1407 select DEBUG_SPINLOCK 1408 select DEBUG_MUTEXES if !PREEMPT_RT 1409 select DEBUG_RT_MUTEXES if PREEMPT_RT 1410 help 1411 This feature enables slowpath testing for w/w mutex users by 1412 injecting additional -EDEADLK wound/backoff cases. Together with 1413 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1414 will test all possible w/w mutex interface abuse with the 1415 exception of simply not acquiring all the required locks. 1416 Note that this feature can introduce significant overhead, so 1417 it really should not be enabled in a production or distro kernel, 1418 even a debug kernel. If you are a driver writer, enable it. If 1419 you are a distro, do not. 1420 1421config DEBUG_RWSEMS 1422 bool "RW Semaphore debugging: basic checks" 1423 depends on DEBUG_KERNEL 1424 help 1425 This debugging feature allows mismatched rw semaphore locks 1426 and unlocks to be detected and reported. 1427 1428config DEBUG_LOCK_ALLOC 1429 bool "Lock debugging: detect incorrect freeing of live locks" 1430 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1431 select DEBUG_SPINLOCK 1432 select DEBUG_MUTEXES if !PREEMPT_RT 1433 select DEBUG_RT_MUTEXES if RT_MUTEXES 1434 select LOCKDEP 1435 help 1436 This feature will check whether any held lock (spinlock, rwlock, 1437 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1438 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1439 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1440 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1441 held during task exit. 1442 1443config LOCKDEP 1444 bool 1445 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1446 select STACKTRACE 1447 select KALLSYMS 1448 select KALLSYMS_ALL 1449 1450config LOCKDEP_SMALL 1451 bool 1452 1453config LOCKDEP_BITS 1454 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1455 depends on LOCKDEP && !LOCKDEP_SMALL 1456 range 10 30 1457 default 15 1458 help 1459 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1460 1461config LOCKDEP_CHAINS_BITS 1462 int "Bitsize for MAX_LOCKDEP_CHAINS" 1463 depends on LOCKDEP && !LOCKDEP_SMALL 1464 range 10 30 1465 default 16 1466 help 1467 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1468 1469config LOCKDEP_STACK_TRACE_BITS 1470 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1471 depends on LOCKDEP && !LOCKDEP_SMALL 1472 range 10 30 1473 default 19 1474 help 1475 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1476 1477config LOCKDEP_STACK_TRACE_HASH_BITS 1478 int "Bitsize for STACK_TRACE_HASH_SIZE" 1479 depends on LOCKDEP && !LOCKDEP_SMALL 1480 range 10 30 1481 default 14 1482 help 1483 Try increasing this value if you need large STACK_TRACE_HASH_SIZE. 1484 1485config LOCKDEP_CIRCULAR_QUEUE_BITS 1486 int "Bitsize for elements in circular_queue struct" 1487 depends on LOCKDEP 1488 range 10 30 1489 default 12 1490 help 1491 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1492 1493config DEBUG_LOCKDEP 1494 bool "Lock dependency engine debugging" 1495 depends on DEBUG_KERNEL && LOCKDEP 1496 select DEBUG_IRQFLAGS 1497 help 1498 If you say Y here, the lock dependency engine will do 1499 additional runtime checks to debug itself, at the price 1500 of more runtime overhead. 1501 1502config DEBUG_ATOMIC_SLEEP 1503 bool "Sleep inside atomic section checking" 1504 select PREEMPT_COUNT 1505 depends on DEBUG_KERNEL 1506 depends on !ARCH_NO_PREEMPT 1507 help 1508 If you say Y here, various routines which may sleep will become very 1509 noisy if they are called inside atomic sections: when a spinlock is 1510 held, inside an rcu read side critical section, inside preempt disabled 1511 sections, inside an interrupt, etc... 1512 1513config DEBUG_LOCKING_API_SELFTESTS 1514 bool "Locking API boot-time self-tests" 1515 depends on DEBUG_KERNEL 1516 help 1517 Say Y here if you want the kernel to run a short self-test during 1518 bootup. The self-test checks whether common types of locking bugs 1519 are detected by debugging mechanisms or not. (if you disable 1520 lock debugging then those bugs won't be detected of course.) 1521 The following locking APIs are covered: spinlocks, rwlocks, 1522 mutexes and rwsems. 1523 1524config LOCK_TORTURE_TEST 1525 tristate "torture tests for locking" 1526 depends on DEBUG_KERNEL 1527 select TORTURE_TEST 1528 help 1529 This option provides a kernel module that runs torture tests 1530 on kernel locking primitives. The kernel module may be built 1531 after the fact on the running kernel to be tested, if desired. 1532 1533 Say Y here if you want kernel locking-primitive torture tests 1534 to be built into the kernel. 1535 Say M if you want these torture tests to build as a module. 1536 Say N if you are unsure. 1537 1538config WW_MUTEX_SELFTEST 1539 tristate "Wait/wound mutex selftests" 1540 help 1541 This option provides a kernel module that runs tests on the 1542 on the struct ww_mutex locking API. 1543 1544 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1545 with this test harness. 1546 1547 Say M if you want these self tests to build as a module. 1548 Say N if you are unsure. 1549 1550config SCF_TORTURE_TEST 1551 tristate "torture tests for smp_call_function*()" 1552 depends on DEBUG_KERNEL 1553 select TORTURE_TEST 1554 help 1555 This option provides a kernel module that runs torture tests 1556 on the smp_call_function() family of primitives. The kernel 1557 module may be built after the fact on the running kernel to 1558 be tested, if desired. 1559 1560config CSD_LOCK_WAIT_DEBUG 1561 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1562 depends on DEBUG_KERNEL 1563 depends on 64BIT 1564 default n 1565 help 1566 This option enables debug prints when CPUs are slow to respond 1567 to the smp_call_function*() IPI wrappers. These debug prints 1568 include the IPI handler function currently executing (if any) 1569 and relevant stack traces. 1570 1571config CSD_LOCK_WAIT_DEBUG_DEFAULT 1572 bool "Default csd_lock_wait() debugging on at boot time" 1573 depends on CSD_LOCK_WAIT_DEBUG 1574 depends on 64BIT 1575 default n 1576 help 1577 This option causes the csdlock_debug= kernel boot parameter to 1578 default to 1 (basic debugging) instead of 0 (no debugging). 1579 1580endmenu # lock debugging 1581 1582config TRACE_IRQFLAGS 1583 depends on TRACE_IRQFLAGS_SUPPORT 1584 bool 1585 help 1586 Enables hooks to interrupt enabling and disabling for 1587 either tracing or lock debugging. 1588 1589config TRACE_IRQFLAGS_NMI 1590 def_bool y 1591 depends on TRACE_IRQFLAGS 1592 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1593 1594config NMI_CHECK_CPU 1595 bool "Debugging for CPUs failing to respond to backtrace requests" 1596 depends on DEBUG_KERNEL 1597 depends on X86 1598 default n 1599 help 1600 Enables debug prints when a CPU fails to respond to a given 1601 backtrace NMI. These prints provide some reasons why a CPU 1602 might legitimately be failing to respond, for example, if it 1603 is offline of if ignore_nmis is set. 1604 1605config DEBUG_IRQFLAGS 1606 bool "Debug IRQ flag manipulation" 1607 help 1608 Enables checks for potentially unsafe enabling or disabling of 1609 interrupts, such as calling raw_local_irq_restore() when interrupts 1610 are enabled. 1611 1612config STACKTRACE 1613 bool "Stack backtrace support" 1614 depends on STACKTRACE_SUPPORT 1615 help 1616 This option causes the kernel to create a /proc/pid/stack for 1617 every process, showing its current stack trace. 1618 It is also used by various kernel debugging features that require 1619 stack trace generation. 1620 1621config WARN_ALL_UNSEEDED_RANDOM 1622 bool "Warn for all uses of unseeded randomness" 1623 default n 1624 help 1625 Some parts of the kernel contain bugs relating to their use of 1626 cryptographically secure random numbers before it's actually possible 1627 to generate those numbers securely. This setting ensures that these 1628 flaws don't go unnoticed, by enabling a message, should this ever 1629 occur. This will allow people with obscure setups to know when things 1630 are going wrong, so that they might contact developers about fixing 1631 it. 1632 1633 Unfortunately, on some models of some architectures getting 1634 a fully seeded CRNG is extremely difficult, and so this can 1635 result in dmesg getting spammed for a surprisingly long 1636 time. This is really bad from a security perspective, and 1637 so architecture maintainers really need to do what they can 1638 to get the CRNG seeded sooner after the system is booted. 1639 However, since users cannot do anything actionable to 1640 address this, by default this option is disabled. 1641 1642 Say Y here if you want to receive warnings for all uses of 1643 unseeded randomness. This will be of use primarily for 1644 those developers interested in improving the security of 1645 Linux kernels running on their architecture (or 1646 subarchitecture). 1647 1648config DEBUG_KOBJECT 1649 bool "kobject debugging" 1650 depends on DEBUG_KERNEL 1651 help 1652 If you say Y here, some extra kobject debugging messages will be sent 1653 to the syslog. 1654 1655config DEBUG_KOBJECT_RELEASE 1656 bool "kobject release debugging" 1657 depends on DEBUG_OBJECTS_TIMERS 1658 help 1659 kobjects are reference counted objects. This means that their 1660 last reference count put is not predictable, and the kobject can 1661 live on past the point at which a driver decides to drop its 1662 initial reference to the kobject gained on allocation. An 1663 example of this would be a struct device which has just been 1664 unregistered. 1665 1666 However, some buggy drivers assume that after such an operation, 1667 the memory backing the kobject can be immediately freed. This 1668 goes completely against the principles of a refcounted object. 1669 1670 If you say Y here, the kernel will delay the release of kobjects 1671 on the last reference count to improve the visibility of this 1672 kind of kobject release bug. 1673 1674config HAVE_DEBUG_BUGVERBOSE 1675 bool 1676 1677menu "Debug kernel data structures" 1678 1679config DEBUG_LIST 1680 bool "Debug linked list manipulation" 1681 depends on DEBUG_KERNEL 1682 select LIST_HARDENED 1683 help 1684 Enable this to turn on extended checks in the linked-list walking 1685 routines. 1686 1687 This option trades better quality error reports for performance, and 1688 is more suitable for kernel debugging. If you care about performance, 1689 you should only enable CONFIG_LIST_HARDENED instead. 1690 1691 If unsure, say N. 1692 1693config DEBUG_PLIST 1694 bool "Debug priority linked list manipulation" 1695 depends on DEBUG_KERNEL 1696 help 1697 Enable this to turn on extended checks in the priority-ordered 1698 linked-list (plist) walking routines. This checks the entire 1699 list multiple times during each manipulation. 1700 1701 If unsure, say N. 1702 1703config DEBUG_SG 1704 bool "Debug SG table operations" 1705 depends on DEBUG_KERNEL 1706 help 1707 Enable this to turn on checks on scatter-gather tables. This can 1708 help find problems with drivers that do not properly initialize 1709 their sg tables. 1710 1711 If unsure, say N. 1712 1713config DEBUG_NOTIFIERS 1714 bool "Debug notifier call chains" 1715 depends on DEBUG_KERNEL 1716 help 1717 Enable this to turn on sanity checking for notifier call chains. 1718 This is most useful for kernel developers to make sure that 1719 modules properly unregister themselves from notifier chains. 1720 This is a relatively cheap check but if you care about maximum 1721 performance, say N. 1722 1723config DEBUG_CLOSURES 1724 bool "Debug closures (bcache async widgits)" 1725 depends on CLOSURES 1726 select DEBUG_FS 1727 help 1728 Keeps all active closures in a linked list and provides a debugfs 1729 interface to list them, which makes it possible to see asynchronous 1730 operations that get stuck. 1731 1732config DEBUG_MAPLE_TREE 1733 bool "Debug maple trees" 1734 depends on DEBUG_KERNEL 1735 help 1736 Enable maple tree debugging information and extra validations. 1737 1738 If unsure, say N. 1739 1740endmenu 1741 1742config DEBUG_CREDENTIALS 1743 bool "Debug credential management" 1744 depends on DEBUG_KERNEL 1745 help 1746 Enable this to turn on some debug checking for credential 1747 management. The additional code keeps track of the number of 1748 pointers from task_structs to any given cred struct, and checks to 1749 see that this number never exceeds the usage count of the cred 1750 struct. 1751 1752 Furthermore, if SELinux is enabled, this also checks that the 1753 security pointer in the cred struct is never seen to be invalid. 1754 1755 If unsure, say N. 1756 1757source "kernel/rcu/Kconfig.debug" 1758 1759config DEBUG_WQ_FORCE_RR_CPU 1760 bool "Force round-robin CPU selection for unbound work items" 1761 depends on DEBUG_KERNEL 1762 default n 1763 help 1764 Workqueue used to implicitly guarantee that work items queued 1765 without explicit CPU specified are put on the local CPU. This 1766 guarantee is no longer true and while local CPU is still 1767 preferred work items may be put on foreign CPUs. Kernel 1768 parameter "workqueue.debug_force_rr_cpu" is added to force 1769 round-robin CPU selection to flush out usages which depend on the 1770 now broken guarantee. This config option enables the debug 1771 feature by default. When enabled, memory and cache locality will 1772 be impacted. 1773 1774config CPU_HOTPLUG_STATE_CONTROL 1775 bool "Enable CPU hotplug state control" 1776 depends on DEBUG_KERNEL 1777 depends on HOTPLUG_CPU 1778 default n 1779 help 1780 Allows to write steps between "offline" and "online" to the CPUs 1781 sysfs target file so states can be stepped granular. This is a debug 1782 option for now as the hotplug machinery cannot be stopped and 1783 restarted at arbitrary points yet. 1784 1785 Say N if your are unsure. 1786 1787config LATENCYTOP 1788 bool "Latency measuring infrastructure" 1789 depends on DEBUG_KERNEL 1790 depends on STACKTRACE_SUPPORT 1791 depends on PROC_FS 1792 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1793 select KALLSYMS 1794 select KALLSYMS_ALL 1795 select STACKTRACE 1796 select SCHEDSTATS 1797 help 1798 Enable this option if you want to use the LatencyTOP tool 1799 to find out which userspace is blocking on what kernel operations. 1800 1801config DEBUG_CGROUP_REF 1802 bool "Disable inlining of cgroup css reference count functions" 1803 depends on DEBUG_KERNEL 1804 depends on CGROUPS 1805 depends on KPROBES 1806 default n 1807 help 1808 Force cgroup css reference count functions to not be inlined so 1809 that they can be kprobed for debugging. 1810 1811source "kernel/trace/Kconfig" 1812 1813config PROVIDE_OHCI1394_DMA_INIT 1814 bool "Remote debugging over FireWire early on boot" 1815 depends on PCI && X86 1816 help 1817 If you want to debug problems which hang or crash the kernel early 1818 on boot and the crashing machine has a FireWire port, you can use 1819 this feature to remotely access the memory of the crashed machine 1820 over FireWire. This employs remote DMA as part of the OHCI1394 1821 specification which is now the standard for FireWire controllers. 1822 1823 With remote DMA, you can monitor the printk buffer remotely using 1824 firescope and access all memory below 4GB using fireproxy from gdb. 1825 Even controlling a kernel debugger is possible using remote DMA. 1826 1827 Usage: 1828 1829 If ohci1394_dma=early is used as boot parameter, it will initialize 1830 all OHCI1394 controllers which are found in the PCI config space. 1831 1832 As all changes to the FireWire bus such as enabling and disabling 1833 devices cause a bus reset and thereby disable remote DMA for all 1834 devices, be sure to have the cable plugged and FireWire enabled on 1835 the debugging host before booting the debug target for debugging. 1836 1837 This code (~1k) is freed after boot. By then, the firewire stack 1838 in charge of the OHCI-1394 controllers should be used instead. 1839 1840 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1841 1842source "samples/Kconfig" 1843 1844config ARCH_HAS_DEVMEM_IS_ALLOWED 1845 bool 1846 1847config STRICT_DEVMEM 1848 bool "Filter access to /dev/mem" 1849 depends on MMU && DEVMEM 1850 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1851 default y if PPC || X86 || ARM64 1852 help 1853 If this option is disabled, you allow userspace (root) access to all 1854 of memory, including kernel and userspace memory. Accidental 1855 access to this is obviously disastrous, but specific access can 1856 be used by people debugging the kernel. Note that with PAT support 1857 enabled, even in this case there are restrictions on /dev/mem 1858 use due to the cache aliasing requirements. 1859 1860 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1861 file only allows userspace access to PCI space and the BIOS code and 1862 data regions. This is sufficient for dosemu and X and all common 1863 users of /dev/mem. 1864 1865 If in doubt, say Y. 1866 1867config IO_STRICT_DEVMEM 1868 bool "Filter I/O access to /dev/mem" 1869 depends on STRICT_DEVMEM 1870 help 1871 If this option is disabled, you allow userspace (root) access to all 1872 io-memory regardless of whether a driver is actively using that 1873 range. Accidental access to this is obviously disastrous, but 1874 specific access can be used by people debugging kernel drivers. 1875 1876 If this option is switched on, the /dev/mem file only allows 1877 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1878 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1879 if the driver using a given range cannot be disabled. 1880 1881 If in doubt, say Y. 1882 1883menu "$(SRCARCH) Debugging" 1884 1885source "arch/$(SRCARCH)/Kconfig.debug" 1886 1887endmenu 1888 1889menu "Kernel Testing and Coverage" 1890 1891source "lib/kunit/Kconfig" 1892 1893config NOTIFIER_ERROR_INJECTION 1894 tristate "Notifier error injection" 1895 depends on DEBUG_KERNEL 1896 select DEBUG_FS 1897 help 1898 This option provides the ability to inject artificial errors to 1899 specified notifier chain callbacks. It is useful to test the error 1900 handling of notifier call chain failures. 1901 1902 Say N if unsure. 1903 1904config PM_NOTIFIER_ERROR_INJECT 1905 tristate "PM notifier error injection module" 1906 depends on PM && NOTIFIER_ERROR_INJECTION 1907 default m if PM_DEBUG 1908 help 1909 This option provides the ability to inject artificial errors to 1910 PM notifier chain callbacks. It is controlled through debugfs 1911 interface /sys/kernel/debug/notifier-error-inject/pm 1912 1913 If the notifier call chain should be failed with some events 1914 notified, write the error code to "actions/<notifier event>/error". 1915 1916 Example: Inject PM suspend error (-12 = -ENOMEM) 1917 1918 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1919 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1920 # echo mem > /sys/power/state 1921 bash: echo: write error: Cannot allocate memory 1922 1923 To compile this code as a module, choose M here: the module will 1924 be called pm-notifier-error-inject. 1925 1926 If unsure, say N. 1927 1928config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1929 tristate "OF reconfig notifier error injection module" 1930 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1931 help 1932 This option provides the ability to inject artificial errors to 1933 OF reconfig notifier chain callbacks. It is controlled 1934 through debugfs interface under 1935 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1936 1937 If the notifier call chain should be failed with some events 1938 notified, write the error code to "actions/<notifier event>/error". 1939 1940 To compile this code as a module, choose M here: the module will 1941 be called of-reconfig-notifier-error-inject. 1942 1943 If unsure, say N. 1944 1945config NETDEV_NOTIFIER_ERROR_INJECT 1946 tristate "Netdev notifier error injection module" 1947 depends on NET && NOTIFIER_ERROR_INJECTION 1948 help 1949 This option provides the ability to inject artificial errors to 1950 netdevice notifier chain callbacks. It is controlled through debugfs 1951 interface /sys/kernel/debug/notifier-error-inject/netdev 1952 1953 If the notifier call chain should be failed with some events 1954 notified, write the error code to "actions/<notifier event>/error". 1955 1956 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1957 1958 # cd /sys/kernel/debug/notifier-error-inject/netdev 1959 # echo -22 > actions/NETDEV_CHANGEMTU/error 1960 # ip link set eth0 mtu 1024 1961 RTNETLINK answers: Invalid argument 1962 1963 To compile this code as a module, choose M here: the module will 1964 be called netdev-notifier-error-inject. 1965 1966 If unsure, say N. 1967 1968config FUNCTION_ERROR_INJECTION 1969 bool "Fault-injections of functions" 1970 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1971 help 1972 Add fault injections into various functions that are annotated with 1973 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1974 value of these functions. This is useful to test error paths of code. 1975 1976 If unsure, say N 1977 1978config FAULT_INJECTION 1979 bool "Fault-injection framework" 1980 depends on DEBUG_KERNEL 1981 help 1982 Provide fault-injection framework. 1983 For more details, see Documentation/fault-injection/. 1984 1985config FAILSLAB 1986 bool "Fault-injection capability for kmalloc" 1987 depends on FAULT_INJECTION 1988 depends on SLAB || SLUB 1989 help 1990 Provide fault-injection capability for kmalloc. 1991 1992config FAIL_PAGE_ALLOC 1993 bool "Fault-injection capability for alloc_pages()" 1994 depends on FAULT_INJECTION 1995 help 1996 Provide fault-injection capability for alloc_pages(). 1997 1998config FAULT_INJECTION_USERCOPY 1999 bool "Fault injection capability for usercopy functions" 2000 depends on FAULT_INJECTION 2001 help 2002 Provides fault-injection capability to inject failures 2003 in usercopy functions (copy_from_user(), get_user(), ...). 2004 2005config FAIL_MAKE_REQUEST 2006 bool "Fault-injection capability for disk IO" 2007 depends on FAULT_INJECTION && BLOCK 2008 help 2009 Provide fault-injection capability for disk IO. 2010 2011config FAIL_IO_TIMEOUT 2012 bool "Fault-injection capability for faking disk interrupts" 2013 depends on FAULT_INJECTION && BLOCK 2014 help 2015 Provide fault-injection capability on end IO handling. This 2016 will make the block layer "forget" an interrupt as configured, 2017 thus exercising the error handling. 2018 2019 Only works with drivers that use the generic timeout handling, 2020 for others it won't do anything. 2021 2022config FAIL_FUTEX 2023 bool "Fault-injection capability for futexes" 2024 select DEBUG_FS 2025 depends on FAULT_INJECTION && FUTEX 2026 help 2027 Provide fault-injection capability for futexes. 2028 2029config FAULT_INJECTION_DEBUG_FS 2030 bool "Debugfs entries for fault-injection capabilities" 2031 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 2032 help 2033 Enable configuration of fault-injection capabilities via debugfs. 2034 2035config FAIL_FUNCTION 2036 bool "Fault-injection capability for functions" 2037 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 2038 help 2039 Provide function-based fault-injection capability. 2040 This will allow you to override a specific function with a return 2041 with given return value. As a result, function caller will see 2042 an error value and have to handle it. This is useful to test the 2043 error handling in various subsystems. 2044 2045config FAIL_MMC_REQUEST 2046 bool "Fault-injection capability for MMC IO" 2047 depends on FAULT_INJECTION_DEBUG_FS && MMC 2048 help 2049 Provide fault-injection capability for MMC IO. 2050 This will make the mmc core return data errors. This is 2051 useful to test the error handling in the mmc block device 2052 and to test how the mmc host driver handles retries from 2053 the block device. 2054 2055config FAIL_SUNRPC 2056 bool "Fault-injection capability for SunRPC" 2057 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2058 help 2059 Provide fault-injection capability for SunRPC and 2060 its consumers. 2061 2062config FAULT_INJECTION_CONFIGFS 2063 bool "Configfs interface for fault-injection capabilities" 2064 depends on FAULT_INJECTION 2065 select CONFIGFS_FS 2066 help 2067 This option allows configfs-based drivers to dynamically configure 2068 fault-injection via configfs. Each parameter for driver-specific 2069 fault-injection can be made visible as a configfs attribute in a 2070 configfs group. 2071 2072 2073config FAULT_INJECTION_STACKTRACE_FILTER 2074 bool "stacktrace filter for fault-injection capabilities" 2075 depends on FAULT_INJECTION 2076 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT 2077 select STACKTRACE 2078 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2079 help 2080 Provide stacktrace filter for fault-injection capabilities 2081 2082config ARCH_HAS_KCOV 2083 bool 2084 help 2085 An architecture should select this when it can successfully 2086 build and run with CONFIG_KCOV. This typically requires 2087 disabling instrumentation for some early boot code. 2088 2089config CC_HAS_SANCOV_TRACE_PC 2090 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2091 2092 2093config KCOV 2094 bool "Code coverage for fuzzing" 2095 depends on ARCH_HAS_KCOV 2096 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2097 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2098 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2099 select DEBUG_FS 2100 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2101 select OBJTOOL if HAVE_NOINSTR_HACK 2102 help 2103 KCOV exposes kernel code coverage information in a form suitable 2104 for coverage-guided fuzzing (randomized testing). 2105 2106 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2107 different machines and across reboots. If you need stable PC values, 2108 disable RANDOMIZE_BASE. 2109 2110 For more details, see Documentation/dev-tools/kcov.rst. 2111 2112config KCOV_ENABLE_COMPARISONS 2113 bool "Enable comparison operands collection by KCOV" 2114 depends on KCOV 2115 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2116 help 2117 KCOV also exposes operands of every comparison in the instrumented 2118 code along with operand sizes and PCs of the comparison instructions. 2119 These operands can be used by fuzzing engines to improve the quality 2120 of fuzzing coverage. 2121 2122config KCOV_INSTRUMENT_ALL 2123 bool "Instrument all code by default" 2124 depends on KCOV 2125 default y 2126 help 2127 If you are doing generic system call fuzzing (like e.g. syzkaller), 2128 then you will want to instrument the whole kernel and you should 2129 say y here. If you are doing more targeted fuzzing (like e.g. 2130 filesystem fuzzing with AFL) then you will want to enable coverage 2131 for more specific subsets of files, and should say n here. 2132 2133config KCOV_IRQ_AREA_SIZE 2134 hex "Size of interrupt coverage collection area in words" 2135 depends on KCOV 2136 default 0x40000 2137 help 2138 KCOV uses preallocated per-cpu areas to collect coverage from 2139 soft interrupts. This specifies the size of those areas in the 2140 number of unsigned long words. 2141 2142menuconfig RUNTIME_TESTING_MENU 2143 bool "Runtime Testing" 2144 def_bool y 2145 2146if RUNTIME_TESTING_MENU 2147 2148config TEST_DHRY 2149 tristate "Dhrystone benchmark test" 2150 help 2151 Enable this to include the Dhrystone 2.1 benchmark. This test 2152 calculates the number of Dhrystones per second, and the number of 2153 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided 2154 by 1757 (the number of Dhrystones per second obtained on the VAX 2155 11/780, nominally a 1 MIPS machine). 2156 2157 To run the benchmark, it needs to be enabled explicitly, either from 2158 the kernel command line (when built-in), or from userspace (when 2159 built-in or modular. 2160 2161 Run once during kernel boot: 2162 2163 test_dhry.run 2164 2165 Set number of iterations from kernel command line: 2166 2167 test_dhry.iterations=<n> 2168 2169 Set number of iterations from userspace: 2170 2171 echo <n> > /sys/module/test_dhry/parameters/iterations 2172 2173 Trigger manual run from userspace: 2174 2175 echo y > /sys/module/test_dhry/parameters/run 2176 2177 If the number of iterations is <= 0, the test will devise a suitable 2178 number of iterations (test runs for at least 2s) automatically. 2179 This process takes ca. 4s. 2180 2181 If unsure, say N. 2182 2183config LKDTM 2184 tristate "Linux Kernel Dump Test Tool Module" 2185 depends on DEBUG_FS 2186 help 2187 This module enables testing of the different dumping mechanisms by 2188 inducing system failures at predefined crash points. 2189 If you don't need it: say N 2190 Choose M here to compile this code as a module. The module will be 2191 called lkdtm. 2192 2193 Documentation on how to use the module can be found in 2194 Documentation/fault-injection/provoke-crashes.rst 2195 2196config CPUMASK_KUNIT_TEST 2197 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2198 depends on KUNIT 2199 default KUNIT_ALL_TESTS 2200 help 2201 Enable to turn on cpumask tests, running at boot or module load time. 2202 2203 For more information on KUnit and unit tests in general, please refer 2204 to the KUnit documentation in Documentation/dev-tools/kunit/. 2205 2206 If unsure, say N. 2207 2208config TEST_LIST_SORT 2209 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2210 depends on KUNIT 2211 default KUNIT_ALL_TESTS 2212 help 2213 Enable this to turn on 'list_sort()' function test. This test is 2214 executed only once during system boot (so affects only boot time), 2215 or at module load time. 2216 2217 If unsure, say N. 2218 2219config TEST_MIN_HEAP 2220 tristate "Min heap test" 2221 depends on DEBUG_KERNEL || m 2222 help 2223 Enable this to turn on min heap function tests. This test is 2224 executed only once during system boot (so affects only boot time), 2225 or at module load time. 2226 2227 If unsure, say N. 2228 2229config TEST_SORT 2230 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2231 depends on KUNIT 2232 default KUNIT_ALL_TESTS 2233 help 2234 This option enables the self-test function of 'sort()' at boot, 2235 or at module load time. 2236 2237 If unsure, say N. 2238 2239config TEST_DIV64 2240 tristate "64bit/32bit division and modulo test" 2241 depends on DEBUG_KERNEL || m 2242 help 2243 Enable this to turn on 'do_div()' function test. This test is 2244 executed only once during system boot (so affects only boot time), 2245 or at module load time. 2246 2247 If unsure, say N. 2248 2249config TEST_IOV_ITER 2250 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS 2251 depends on KUNIT 2252 default KUNIT_ALL_TESTS 2253 help 2254 Enable this to turn on testing of the operation of the I/O iterator 2255 (iov_iter). This test is executed only once during system boot (so 2256 affects only boot time), or at module load time. 2257 2258 If unsure, say N. 2259 2260config KPROBES_SANITY_TEST 2261 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2262 depends on DEBUG_KERNEL 2263 depends on KPROBES 2264 depends on KUNIT 2265 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2266 default KUNIT_ALL_TESTS 2267 help 2268 This option provides for testing basic kprobes functionality on 2269 boot. Samples of kprobe and kretprobe are inserted and 2270 verified for functionality. 2271 2272 Say N if you are unsure. 2273 2274config FPROBE_SANITY_TEST 2275 bool "Self test for fprobe" 2276 depends on DEBUG_KERNEL 2277 depends on FPROBE 2278 depends on KUNIT=y 2279 help 2280 This option will enable testing the fprobe when the system boot. 2281 A series of tests are made to verify that the fprobe is functioning 2282 properly. 2283 2284 Say N if you are unsure. 2285 2286config BACKTRACE_SELF_TEST 2287 tristate "Self test for the backtrace code" 2288 depends on DEBUG_KERNEL 2289 help 2290 This option provides a kernel module that can be used to test 2291 the kernel stack backtrace code. This option is not useful 2292 for distributions or general kernels, but only for kernel 2293 developers working on architecture code. 2294 2295 Note that if you want to also test saved backtraces, you will 2296 have to enable STACKTRACE as well. 2297 2298 Say N if you are unsure. 2299 2300config TEST_REF_TRACKER 2301 tristate "Self test for reference tracker" 2302 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2303 select REF_TRACKER 2304 help 2305 This option provides a kernel module performing tests 2306 using reference tracker infrastructure. 2307 2308 Say N if you are unsure. 2309 2310config RBTREE_TEST 2311 tristate "Red-Black tree test" 2312 depends on DEBUG_KERNEL 2313 help 2314 A benchmark measuring the performance of the rbtree library. 2315 Also includes rbtree invariant checks. 2316 2317config REED_SOLOMON_TEST 2318 tristate "Reed-Solomon library test" 2319 depends on DEBUG_KERNEL || m 2320 select REED_SOLOMON 2321 select REED_SOLOMON_ENC16 2322 select REED_SOLOMON_DEC16 2323 help 2324 This option enables the self-test function of rslib at boot, 2325 or at module load time. 2326 2327 If unsure, say N. 2328 2329config INTERVAL_TREE_TEST 2330 tristate "Interval tree test" 2331 depends on DEBUG_KERNEL 2332 select INTERVAL_TREE 2333 help 2334 A benchmark measuring the performance of the interval tree library 2335 2336config PERCPU_TEST 2337 tristate "Per cpu operations test" 2338 depends on m && DEBUG_KERNEL 2339 help 2340 Enable this option to build test module which validates per-cpu 2341 operations. 2342 2343 If unsure, say N. 2344 2345config ATOMIC64_SELFTEST 2346 tristate "Perform an atomic64_t self-test" 2347 help 2348 Enable this option to test the atomic64_t functions at boot or 2349 at module load time. 2350 2351 If unsure, say N. 2352 2353config ASYNC_RAID6_TEST 2354 tristate "Self test for hardware accelerated raid6 recovery" 2355 depends on ASYNC_RAID6_RECOV 2356 select ASYNC_MEMCPY 2357 help 2358 This is a one-shot self test that permutes through the 2359 recovery of all the possible two disk failure scenarios for a 2360 N-disk array. Recovery is performed with the asynchronous 2361 raid6 recovery routines, and will optionally use an offload 2362 engine if one is available. 2363 2364 If unsure, say N. 2365 2366config TEST_HEXDUMP 2367 tristate "Test functions located in the hexdump module at runtime" 2368 2369config STRING_SELFTEST 2370 tristate "Test string functions at runtime" 2371 2372config TEST_STRING_HELPERS 2373 tristate "Test functions located in the string_helpers module at runtime" 2374 2375config TEST_KSTRTOX 2376 tristate "Test kstrto*() family of functions at runtime" 2377 2378config TEST_PRINTF 2379 tristate "Test printf() family of functions at runtime" 2380 2381config TEST_SCANF 2382 tristate "Test scanf() family of functions at runtime" 2383 2384config TEST_BITMAP 2385 tristate "Test bitmap_*() family of functions at runtime" 2386 help 2387 Enable this option to test the bitmap functions at boot. 2388 2389 If unsure, say N. 2390 2391config TEST_UUID 2392 tristate "Test functions located in the uuid module at runtime" 2393 2394config TEST_XARRAY 2395 tristate "Test the XArray code at runtime" 2396 2397config TEST_MAPLE_TREE 2398 tristate "Test the Maple Tree code at runtime or module load" 2399 help 2400 Enable this option to test the maple tree code functions at boot, or 2401 when the module is loaded. Enable "Debug Maple Trees" will enable 2402 more verbose output on failures. 2403 2404 If unsure, say N. 2405 2406config TEST_RHASHTABLE 2407 tristate "Perform selftest on resizable hash table" 2408 help 2409 Enable this option to test the rhashtable functions at boot. 2410 2411 If unsure, say N. 2412 2413config TEST_IDA 2414 tristate "Perform selftest on IDA functions" 2415 2416config TEST_PARMAN 2417 tristate "Perform selftest on priority array manager" 2418 depends on PARMAN 2419 help 2420 Enable this option to test priority array manager on boot 2421 (or module load). 2422 2423 If unsure, say N. 2424 2425config TEST_IRQ_TIMINGS 2426 bool "IRQ timings selftest" 2427 depends on IRQ_TIMINGS 2428 help 2429 Enable this option to test the irq timings code on boot. 2430 2431 If unsure, say N. 2432 2433config TEST_LKM 2434 tristate "Test module loading with 'hello world' module" 2435 depends on m 2436 help 2437 This builds the "test_module" module that emits "Hello, world" 2438 on printk when loaded. It is designed to be used for basic 2439 evaluation of the module loading subsystem (for example when 2440 validating module verification). It lacks any extra dependencies, 2441 and will not normally be loaded by the system unless explicitly 2442 requested by name. 2443 2444 If unsure, say N. 2445 2446config TEST_BITOPS 2447 tristate "Test module for compilation of bitops operations" 2448 depends on m 2449 help 2450 This builds the "test_bitops" module that is much like the 2451 TEST_LKM module except that it does a basic exercise of the 2452 set/clear_bit macros and get_count_order/long to make sure there are 2453 no compiler warnings from C=1 sparse checker or -Wextra 2454 compilations. It has no dependencies and doesn't run or load unless 2455 explicitly requested by name. for example: modprobe test_bitops. 2456 2457 If unsure, say N. 2458 2459config TEST_VMALLOC 2460 tristate "Test module for stress/performance analysis of vmalloc allocator" 2461 default n 2462 depends on MMU 2463 depends on m 2464 help 2465 This builds the "test_vmalloc" module that should be used for 2466 stress and performance analysis. So, any new change for vmalloc 2467 subsystem can be evaluated from performance and stability point 2468 of view. 2469 2470 If unsure, say N. 2471 2472config TEST_USER_COPY 2473 tristate "Test user/kernel boundary protections" 2474 depends on m 2475 help 2476 This builds the "test_user_copy" module that runs sanity checks 2477 on the copy_to/from_user infrastructure, making sure basic 2478 user/kernel boundary testing is working. If it fails to load, 2479 a regression has been detected in the user/kernel memory boundary 2480 protections. 2481 2482 If unsure, say N. 2483 2484config TEST_BPF 2485 tristate "Test BPF filter functionality" 2486 depends on m && NET 2487 help 2488 This builds the "test_bpf" module that runs various test vectors 2489 against the BPF interpreter or BPF JIT compiler depending on the 2490 current setting. This is in particular useful for BPF JIT compiler 2491 development, but also to run regression tests against changes in 2492 the interpreter code. It also enables test stubs for eBPF maps and 2493 verifier used by user space verifier testsuite. 2494 2495 If unsure, say N. 2496 2497config TEST_BLACKHOLE_DEV 2498 tristate "Test blackhole netdev functionality" 2499 depends on m && NET 2500 help 2501 This builds the "test_blackhole_dev" module that validates the 2502 data path through this blackhole netdev. 2503 2504 If unsure, say N. 2505 2506config FIND_BIT_BENCHMARK 2507 tristate "Test find_bit functions" 2508 help 2509 This builds the "test_find_bit" module that measure find_*_bit() 2510 functions performance. 2511 2512 If unsure, say N. 2513 2514config TEST_FIRMWARE 2515 tristate "Test firmware loading via userspace interface" 2516 depends on FW_LOADER 2517 help 2518 This builds the "test_firmware" module that creates a userspace 2519 interface for testing firmware loading. This can be used to 2520 control the triggering of firmware loading without needing an 2521 actual firmware-using device. The contents can be rechecked by 2522 userspace. 2523 2524 If unsure, say N. 2525 2526config TEST_SYSCTL 2527 tristate "sysctl test driver" 2528 depends on PROC_SYSCTL 2529 help 2530 This builds the "test_sysctl" module. This driver enables to test the 2531 proc sysctl interfaces available to drivers safely without affecting 2532 production knobs which might alter system functionality. 2533 2534 If unsure, say N. 2535 2536config BITFIELD_KUNIT 2537 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2538 depends on KUNIT 2539 default KUNIT_ALL_TESTS 2540 help 2541 Enable this option to test the bitfield functions at boot. 2542 2543 KUnit tests run during boot and output the results to the debug log 2544 in TAP format (http://testanything.org/). Only useful for kernel devs 2545 running the KUnit test harness, and not intended for inclusion into a 2546 production build. 2547 2548 For more information on KUnit and unit tests in general please refer 2549 to the KUnit documentation in Documentation/dev-tools/kunit/. 2550 2551 If unsure, say N. 2552 2553config CHECKSUM_KUNIT 2554 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS 2555 depends on KUNIT 2556 default KUNIT_ALL_TESTS 2557 help 2558 Enable this option to test the checksum functions at boot. 2559 2560 KUnit tests run during boot and output the results to the debug log 2561 in TAP format (http://testanything.org/). Only useful for kernel devs 2562 running the KUnit test harness, and not intended for inclusion into a 2563 production build. 2564 2565 For more information on KUnit and unit tests in general please refer 2566 to the KUnit documentation in Documentation/dev-tools/kunit/. 2567 2568 If unsure, say N. 2569 2570config HASH_KUNIT_TEST 2571 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2572 depends on KUNIT 2573 default KUNIT_ALL_TESTS 2574 help 2575 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2576 integer (<linux/hash.h>) hash functions on boot. 2577 2578 KUnit tests run during boot and output the results to the debug log 2579 in TAP format (https://testanything.org/). Only useful for kernel devs 2580 running the KUnit test harness, and not intended for inclusion into a 2581 production build. 2582 2583 For more information on KUnit and unit tests in general please refer 2584 to the KUnit documentation in Documentation/dev-tools/kunit/. 2585 2586 This is intended to help people writing architecture-specific 2587 optimized versions. If unsure, say N. 2588 2589config RESOURCE_KUNIT_TEST 2590 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2591 depends on KUNIT 2592 default KUNIT_ALL_TESTS 2593 help 2594 This builds the resource API unit test. 2595 Tests the logic of API provided by resource.c and ioport.h. 2596 For more information on KUnit and unit tests in general please refer 2597 to the KUnit documentation in Documentation/dev-tools/kunit/. 2598 2599 If unsure, say N. 2600 2601config SYSCTL_KUNIT_TEST 2602 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2603 depends on KUNIT 2604 default KUNIT_ALL_TESTS 2605 help 2606 This builds the proc sysctl unit test, which runs on boot. 2607 Tests the API contract and implementation correctness of sysctl. 2608 For more information on KUnit and unit tests in general please refer 2609 to the KUnit documentation in Documentation/dev-tools/kunit/. 2610 2611 If unsure, say N. 2612 2613config LIST_KUNIT_TEST 2614 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2615 depends on KUNIT 2616 default KUNIT_ALL_TESTS 2617 help 2618 This builds the linked list KUnit test suite. 2619 It tests that the API and basic functionality of the list_head type 2620 and associated macros. 2621 2622 KUnit tests run during boot and output the results to the debug log 2623 in TAP format (https://testanything.org/). Only useful for kernel devs 2624 running the KUnit test harness, and not intended for inclusion into a 2625 production build. 2626 2627 For more information on KUnit and unit tests in general please refer 2628 to the KUnit documentation in Documentation/dev-tools/kunit/. 2629 2630 If unsure, say N. 2631 2632config HASHTABLE_KUNIT_TEST 2633 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS 2634 depends on KUNIT 2635 default KUNIT_ALL_TESTS 2636 help 2637 This builds the hashtable KUnit test suite. 2638 It tests the basic functionality of the API defined in 2639 include/linux/hashtable.h. For more information on KUnit and 2640 unit tests in general please refer to the KUnit documentation 2641 in Documentation/dev-tools/kunit/. 2642 2643 If unsure, say N. 2644 2645config LINEAR_RANGES_TEST 2646 tristate "KUnit test for linear_ranges" 2647 depends on KUNIT 2648 select LINEAR_RANGES 2649 help 2650 This builds the linear_ranges unit test, which runs on boot. 2651 Tests the linear_ranges logic correctness. 2652 For more information on KUnit and unit tests in general please refer 2653 to the KUnit documentation in Documentation/dev-tools/kunit/. 2654 2655 If unsure, say N. 2656 2657config CMDLINE_KUNIT_TEST 2658 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2659 depends on KUNIT 2660 default KUNIT_ALL_TESTS 2661 help 2662 This builds the cmdline API unit test. 2663 Tests the logic of API provided by cmdline.c. 2664 For more information on KUnit and unit tests in general please refer 2665 to the KUnit documentation in Documentation/dev-tools/kunit/. 2666 2667 If unsure, say N. 2668 2669config BITS_TEST 2670 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2671 depends on KUNIT 2672 default KUNIT_ALL_TESTS 2673 help 2674 This builds the bits unit test. 2675 Tests the logic of macros defined in bits.h. 2676 For more information on KUnit and unit tests in general please refer 2677 to the KUnit documentation in Documentation/dev-tools/kunit/. 2678 2679 If unsure, say N. 2680 2681config SLUB_KUNIT_TEST 2682 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2683 depends on SLUB_DEBUG && KUNIT 2684 default KUNIT_ALL_TESTS 2685 help 2686 This builds SLUB allocator unit test. 2687 Tests SLUB cache debugging functionality. 2688 For more information on KUnit and unit tests in general please refer 2689 to the KUnit documentation in Documentation/dev-tools/kunit/. 2690 2691 If unsure, say N. 2692 2693config RATIONAL_KUNIT_TEST 2694 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2695 depends on KUNIT && RATIONAL 2696 default KUNIT_ALL_TESTS 2697 help 2698 This builds the rational math unit test. 2699 For more information on KUnit and unit tests in general please refer 2700 to the KUnit documentation in Documentation/dev-tools/kunit/. 2701 2702 If unsure, say N. 2703 2704config MEMCPY_KUNIT_TEST 2705 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2706 depends on KUNIT 2707 default KUNIT_ALL_TESTS 2708 help 2709 Builds unit tests for memcpy(), memmove(), and memset() functions. 2710 For more information on KUnit and unit tests in general please refer 2711 to the KUnit documentation in Documentation/dev-tools/kunit/. 2712 2713 If unsure, say N. 2714 2715config MEMCPY_SLOW_KUNIT_TEST 2716 bool "Include exhaustive memcpy tests" 2717 depends on MEMCPY_KUNIT_TEST 2718 default y 2719 help 2720 Some memcpy tests are quite exhaustive in checking for overlaps 2721 and bit ranges. These can be very slow, so they are split out 2722 as a separate config, in case they need to be disabled. 2723 2724 Note this config option will be replaced by the use of KUnit test 2725 attributes. 2726 2727config IS_SIGNED_TYPE_KUNIT_TEST 2728 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2729 depends on KUNIT 2730 default KUNIT_ALL_TESTS 2731 help 2732 Builds unit tests for the is_signed_type() macro. 2733 2734 For more information on KUnit and unit tests in general please refer 2735 to the KUnit documentation in Documentation/dev-tools/kunit/. 2736 2737 If unsure, say N. 2738 2739config OVERFLOW_KUNIT_TEST 2740 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2741 depends on KUNIT 2742 default KUNIT_ALL_TESTS 2743 help 2744 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2745 related functions. 2746 2747 For more information on KUnit and unit tests in general please refer 2748 to the KUnit documentation in Documentation/dev-tools/kunit/. 2749 2750 If unsure, say N. 2751 2752config STACKINIT_KUNIT_TEST 2753 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2754 depends on KUNIT 2755 default KUNIT_ALL_TESTS 2756 help 2757 Test if the kernel is zero-initializing stack variables and 2758 padding. Coverage is controlled by compiler flags, 2759 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2760 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2761 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2762 2763config FORTIFY_KUNIT_TEST 2764 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2765 depends on KUNIT && FORTIFY_SOURCE 2766 default KUNIT_ALL_TESTS 2767 help 2768 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2769 by the str*() and mem*() family of functions. For testing runtime 2770 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2771 2772config HW_BREAKPOINT_KUNIT_TEST 2773 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2774 depends on HAVE_HW_BREAKPOINT 2775 depends on KUNIT=y 2776 default KUNIT_ALL_TESTS 2777 help 2778 Tests for hw_breakpoint constraints accounting. 2779 2780 If unsure, say N. 2781 2782config STRCAT_KUNIT_TEST 2783 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS 2784 depends on KUNIT 2785 default KUNIT_ALL_TESTS 2786 2787config STRSCPY_KUNIT_TEST 2788 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2789 depends on KUNIT 2790 default KUNIT_ALL_TESTS 2791 2792config SIPHASH_KUNIT_TEST 2793 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2794 depends on KUNIT 2795 default KUNIT_ALL_TESTS 2796 help 2797 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2798 functions on boot (or module load). 2799 2800 This is intended to help people writing architecture-specific 2801 optimized versions. If unsure, say N. 2802 2803config TEST_UDELAY 2804 tristate "udelay test driver" 2805 help 2806 This builds the "udelay_test" module that helps to make sure 2807 that udelay() is working properly. 2808 2809 If unsure, say N. 2810 2811config TEST_STATIC_KEYS 2812 tristate "Test static keys" 2813 depends on m 2814 help 2815 Test the static key interfaces. 2816 2817 If unsure, say N. 2818 2819config TEST_DYNAMIC_DEBUG 2820 tristate "Test DYNAMIC_DEBUG" 2821 depends on DYNAMIC_DEBUG 2822 help 2823 This module registers a tracer callback to count enabled 2824 pr_debugs in a 'do_debugging' function, then alters their 2825 enablements, calls the function, and compares counts. 2826 2827 If unsure, say N. 2828 2829config TEST_KMOD 2830 tristate "kmod stress tester" 2831 depends on m 2832 depends on NETDEVICES && NET_CORE && INET # for TUN 2833 depends on BLOCK 2834 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2835 select TEST_LKM 2836 select XFS_FS 2837 select TUN 2838 select BTRFS_FS 2839 help 2840 Test the kernel's module loading mechanism: kmod. kmod implements 2841 support to load modules using the Linux kernel's usermode helper. 2842 This test provides a series of tests against kmod. 2843 2844 Although technically you can either build test_kmod as a module or 2845 into the kernel we disallow building it into the kernel since 2846 it stress tests request_module() and this will very likely cause 2847 some issues by taking over precious threads available from other 2848 module load requests, ultimately this could be fatal. 2849 2850 To run tests run: 2851 2852 tools/testing/selftests/kmod/kmod.sh --help 2853 2854 If unsure, say N. 2855 2856config TEST_DEBUG_VIRTUAL 2857 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2858 depends on DEBUG_VIRTUAL 2859 help 2860 Test the kernel's ability to detect incorrect calls to 2861 virt_to_phys() done against the non-linear part of the 2862 kernel's virtual address map. 2863 2864 If unsure, say N. 2865 2866config TEST_MEMCAT_P 2867 tristate "Test memcat_p() helper function" 2868 help 2869 Test the memcat_p() helper for correctly merging two 2870 pointer arrays together. 2871 2872 If unsure, say N. 2873 2874config TEST_LIVEPATCH 2875 tristate "Test livepatching" 2876 default n 2877 depends on DYNAMIC_DEBUG 2878 depends on LIVEPATCH 2879 depends on m 2880 help 2881 Test kernel livepatching features for correctness. The tests will 2882 load test modules that will be livepatched in various scenarios. 2883 2884 To run all the livepatching tests: 2885 2886 make -C tools/testing/selftests TARGETS=livepatch run_tests 2887 2888 Alternatively, individual tests may be invoked: 2889 2890 tools/testing/selftests/livepatch/test-callbacks.sh 2891 tools/testing/selftests/livepatch/test-livepatch.sh 2892 tools/testing/selftests/livepatch/test-shadow-vars.sh 2893 2894 If unsure, say N. 2895 2896config TEST_OBJAGG 2897 tristate "Perform selftest on object aggreration manager" 2898 default n 2899 depends on OBJAGG 2900 help 2901 Enable this option to test object aggregation manager on boot 2902 (or module load). 2903 2904config TEST_MEMINIT 2905 tristate "Test heap/page initialization" 2906 help 2907 Test if the kernel is zero-initializing heap and page allocations. 2908 This can be useful to test init_on_alloc and init_on_free features. 2909 2910 If unsure, say N. 2911 2912config TEST_HMM 2913 tristate "Test HMM (Heterogeneous Memory Management)" 2914 depends on TRANSPARENT_HUGEPAGE 2915 depends on DEVICE_PRIVATE 2916 select HMM_MIRROR 2917 select MMU_NOTIFIER 2918 help 2919 This is a pseudo device driver solely for testing HMM. 2920 Say M here if you want to build the HMM test module. 2921 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2922 2923 If unsure, say N. 2924 2925config TEST_FREE_PAGES 2926 tristate "Test freeing pages" 2927 help 2928 Test that a memory leak does not occur due to a race between 2929 freeing a block of pages and a speculative page reference. 2930 Loading this module is safe if your kernel has the bug fixed. 2931 If the bug is not fixed, it will leak gigabytes of memory and 2932 probably OOM your system. 2933 2934config TEST_FPU 2935 tristate "Test floating point operations in kernel space" 2936 depends on X86 && !KCOV_INSTRUMENT_ALL 2937 help 2938 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2939 which will trigger a sequence of floating point operations. This is used 2940 for self-testing floating point control register setting in 2941 kernel_fpu_begin(). 2942 2943 If unsure, say N. 2944 2945config TEST_CLOCKSOURCE_WATCHDOG 2946 tristate "Test clocksource watchdog in kernel space" 2947 depends on CLOCKSOURCE_WATCHDOG 2948 help 2949 Enable this option to create a kernel module that will trigger 2950 a test of the clocksource watchdog. This module may be loaded 2951 via modprobe or insmod in which case it will run upon being 2952 loaded, or it may be built in, in which case it will run 2953 shortly after boot. 2954 2955 If unsure, say N. 2956 2957config TEST_OBJPOOL 2958 tristate "Test module for correctness and stress of objpool" 2959 default n 2960 depends on m && DEBUG_KERNEL 2961 help 2962 This builds the "test_objpool" module that should be used for 2963 correctness verification and concurrent testings of objects 2964 allocation and reclamation. 2965 2966 If unsure, say N. 2967 2968endif # RUNTIME_TESTING_MENU 2969 2970config ARCH_USE_MEMTEST 2971 bool 2972 help 2973 An architecture should select this when it uses early_memtest() 2974 during boot process. 2975 2976config MEMTEST 2977 bool "Memtest" 2978 depends on ARCH_USE_MEMTEST 2979 help 2980 This option adds a kernel parameter 'memtest', which allows memtest 2981 to be set and executed. 2982 memtest=0, mean disabled; -- default 2983 memtest=1, mean do 1 test pattern; 2984 ... 2985 memtest=17, mean do 17 test patterns. 2986 If you are unsure how to answer this question, answer N. 2987 2988 2989 2990config HYPERV_TESTING 2991 bool "Microsoft Hyper-V driver testing" 2992 default n 2993 depends on HYPERV && DEBUG_FS 2994 help 2995 Select this option to enable Hyper-V vmbus testing. 2996 2997endmenu # "Kernel Testing and Coverage" 2998 2999menu "Rust hacking" 3000 3001config RUST_DEBUG_ASSERTIONS 3002 bool "Debug assertions" 3003 depends on RUST 3004 help 3005 Enables rustc's `-Cdebug-assertions` codegen option. 3006 3007 This flag lets you turn `cfg(debug_assertions)` conditional 3008 compilation on or off. This can be used to enable extra debugging 3009 code in development but not in production. For example, it controls 3010 the behavior of the standard library's `debug_assert!` macro. 3011 3012 Note that this will apply to all Rust code, including `core`. 3013 3014 If unsure, say N. 3015 3016config RUST_OVERFLOW_CHECKS 3017 bool "Overflow checks" 3018 default y 3019 depends on RUST 3020 help 3021 Enables rustc's `-Coverflow-checks` codegen option. 3022 3023 This flag allows you to control the behavior of runtime integer 3024 overflow. When overflow-checks are enabled, a Rust panic will occur 3025 on overflow. 3026 3027 Note that this will apply to all Rust code, including `core`. 3028 3029 If unsure, say Y. 3030 3031config RUST_BUILD_ASSERT_ALLOW 3032 bool "Allow unoptimized build-time assertions" 3033 depends on RUST 3034 help 3035 Controls how are `build_error!` and `build_assert!` handled during build. 3036 3037 If calls to them exist in the binary, it may indicate a violated invariant 3038 or that the optimizer failed to verify the invariant during compilation. 3039 3040 This should not happen, thus by default the build is aborted. However, 3041 as an escape hatch, you can choose Y here to ignore them during build 3042 and let the check be carried at runtime (with `panic!` being called if 3043 the check fails). 3044 3045 If unsure, say N. 3046 3047config RUST_KERNEL_DOCTESTS 3048 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS 3049 depends on RUST && KUNIT=y 3050 default KUNIT_ALL_TESTS 3051 help 3052 This builds the documentation tests of the `kernel` crate 3053 as KUnit tests. 3054 3055 For more information on KUnit and unit tests in general, 3056 please refer to the KUnit documentation in Documentation/dev-tools/kunit/. 3057 3058 If unsure, say N. 3059 3060endmenu # "Rust" 3061 3062endmenu # Kernel hacking 3063