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 type information" 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 bool "Generate BTF type information for kernel modules" 408 default y 409 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 410 help 411 Generate compact split BTF type information for kernel modules. 412 413config MODULE_ALLOW_BTF_MISMATCH 414 bool "Allow loading modules with non-matching BTF type info" 415 depends on DEBUG_INFO_BTF_MODULES 416 help 417 For modules whose split BTF does not match vmlinux, load without 418 BTF rather than refusing to load. The default behavior with 419 module BTF enabled is to reject modules with such mismatches; 420 this option will still load module BTF where possible but ignore 421 it when a mismatch is found. 422 423config GDB_SCRIPTS 424 bool "Provide GDB scripts for kernel debugging" 425 help 426 This creates the required links to GDB helper scripts in the 427 build directory. If you load vmlinux into gdb, the helper 428 scripts will be automatically imported by gdb as well, and 429 additional functions are available to analyze a Linux kernel 430 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 431 for further details. 432 433endif # DEBUG_INFO 434 435config FRAME_WARN 436 int "Warn for stack frames larger than" 437 range 0 8192 438 default 0 if KMSAN 439 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 440 default 2048 if PARISC 441 default 1536 if (!64BIT && XTENSA) 442 default 1280 if KASAN && !64BIT 443 default 1024 if !64BIT 444 default 2048 if 64BIT 445 help 446 Tell the compiler to warn at build time for stack frames larger than this. 447 Setting this too low will cause a lot of warnings. 448 Setting it to 0 disables the warning. 449 450config STRIP_ASM_SYMS 451 bool "Strip assembler-generated symbols during link" 452 default n 453 help 454 Strip internal assembler-generated symbols during a link (symbols 455 that look like '.Lxxx') so they don't pollute the output of 456 get_wchan() and suchlike. 457 458config READABLE_ASM 459 bool "Generate readable assembler code" 460 depends on DEBUG_KERNEL 461 depends on CC_IS_GCC 462 help 463 Disable some compiler optimizations that tend to generate human unreadable 464 assembler output. This may make the kernel slightly slower, but it helps 465 to keep kernel developers who have to stare a lot at assembler listings 466 sane. 467 468config HEADERS_INSTALL 469 bool "Install uapi headers to usr/include" 470 depends on !UML 471 help 472 This option will install uapi headers (headers exported to user-space) 473 into the usr/include directory for use during the kernel build. 474 This is unneeded for building the kernel itself, but needed for some 475 user-space program samples. It is also needed by some features such 476 as uapi header sanity checks. 477 478config DEBUG_SECTION_MISMATCH 479 bool "Enable full Section mismatch analysis" 480 depends on CC_IS_GCC 481 help 482 The section mismatch analysis checks if there are illegal 483 references from one section to another section. 484 During linktime or runtime, some sections are dropped; 485 any use of code/data previously in these sections would 486 most likely result in an oops. 487 In the code, functions and variables are annotated with 488 __init,, etc. (see the full list in include/linux/init.h), 489 which results in the code/data being placed in specific sections. 490 The section mismatch analysis is always performed after a full 491 kernel build, and enabling this option causes the following 492 additional step to occur: 493 - Add the option -fno-inline-functions-called-once to gcc commands. 494 When inlining a function annotated with __init in a non-init 495 function, we would lose the section information and thus 496 the analysis would not catch the illegal reference. 497 This option tells gcc to inline less (but it does result in 498 a larger kernel). 499 500config SECTION_MISMATCH_WARN_ONLY 501 bool "Make section mismatch errors non-fatal" 502 default y 503 help 504 If you say N here, the build process will fail if there are any 505 section mismatch, instead of just throwing warnings. 506 507 If unsure, say Y. 508 509config DEBUG_FORCE_FUNCTION_ALIGN_64B 510 bool "Force all function address 64B aligned" 511 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC || RISCV || S390) 512 select FUNCTION_ALIGNMENT_64B 513 help 514 There are cases that a commit from one domain changes the function 515 address alignment of other domains, and cause magic performance 516 bump (regression or improvement). Enable this option will help to 517 verify if the bump is caused by function alignment changes, while 518 it will slightly increase the kernel size and affect icache usage. 519 520 It is mainly for debug and performance tuning use. 521 522# 523# Select this config option from the architecture Kconfig, if it 524# is preferred to always offer frame pointers as a config 525# option on the architecture (regardless of KERNEL_DEBUG): 526# 527config ARCH_WANT_FRAME_POINTERS 528 bool 529 530config FRAME_POINTER 531 bool "Compile the kernel with frame pointers" 532 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 533 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 534 help 535 If you say Y here the resulting kernel image will be slightly 536 larger and slower, but it gives very useful debugging information 537 in case of kernel bugs. (precise oopses/stacktraces/warnings) 538 539config OBJTOOL 540 bool 541 542config STACK_VALIDATION 543 bool "Compile-time stack metadata validation" 544 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 545 select OBJTOOL 546 default n 547 help 548 Validate frame pointer rules at compile-time. This helps ensure that 549 runtime stack traces are more reliable. 550 551 For more information, see 552 tools/objtool/Documentation/objtool.txt. 553 554config NOINSTR_VALIDATION 555 bool 556 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 557 select OBJTOOL 558 default y 559 560config VMLINUX_MAP 561 bool "Generate vmlinux.map file when linking" 562 depends on EXPERT 563 help 564 Selecting this option will pass "-Map=vmlinux.map" to ld 565 when linking vmlinux. That file can be useful for verifying 566 and debugging magic section games, and for seeing which 567 pieces of code get eliminated with 568 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 569 570config DEBUG_FORCE_WEAK_PER_CPU 571 bool "Force weak per-cpu definitions" 572 depends on DEBUG_KERNEL 573 help 574 s390 and alpha require percpu variables in modules to be 575 defined weak to work around addressing range issue which 576 puts the following two restrictions on percpu variable 577 definitions. 578 579 1. percpu symbols must be unique whether static or not 580 2. percpu variables can't be defined inside a function 581 582 To ensure that generic code follows the above rules, this 583 option forces all percpu variables to be defined as weak. 584 585endmenu # "Compiler options" 586 587menu "Generic Kernel Debugging Instruments" 588 589config MAGIC_SYSRQ 590 bool "Magic SysRq key" 591 depends on !UML 592 help 593 If you say Y here, you will have some control over the system even 594 if the system crashes for example during kernel debugging (e.g., you 595 will be able to flush the buffer cache to disk, reboot the system 596 immediately or dump some status information). This is accomplished 597 by pressing various keys while holding SysRq (Alt+PrintScreen). It 598 also works on a serial console (on PC hardware at least), if you 599 send a BREAK and then within 5 seconds a command keypress. The 600 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 601 Don't say Y unless you really know what this hack does. 602 603config MAGIC_SYSRQ_DEFAULT_ENABLE 604 hex "Enable magic SysRq key functions by default" 605 depends on MAGIC_SYSRQ 606 default 0x1 607 help 608 Specifies which SysRq key functions are enabled by default. 609 This may be set to 1 or 0 to enable or disable them all, or 610 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 611 612config MAGIC_SYSRQ_SERIAL 613 bool "Enable magic SysRq key over serial" 614 depends on MAGIC_SYSRQ 615 default y 616 help 617 Many embedded boards have a disconnected TTL level serial which can 618 generate some garbage that can lead to spurious false sysrq detects. 619 This option allows you to decide whether you want to enable the 620 magic SysRq key. 621 622config MAGIC_SYSRQ_SERIAL_SEQUENCE 623 string "Char sequence that enables magic SysRq over serial" 624 depends on MAGIC_SYSRQ_SERIAL 625 default "" 626 help 627 Specifies a sequence of characters that can follow BREAK to enable 628 SysRq on a serial console. 629 630 If unsure, leave an empty string and the option will not be enabled. 631 632config DEBUG_FS 633 bool "Debug Filesystem" 634 help 635 debugfs is a virtual file system that kernel developers use to put 636 debugging files into. Enable this option to be able to read and 637 write to these files. 638 639 For detailed documentation on the debugfs API, see 640 Documentation/filesystems/. 641 642 If unsure, say N. 643 644choice 645 prompt "Debugfs default access" 646 depends on DEBUG_FS 647 default DEBUG_FS_ALLOW_ALL 648 help 649 This selects the default access restrictions for debugfs. 650 It can be overridden with kernel command line option 651 debugfs=[on,no-mount,off]. The restrictions apply for API access 652 and filesystem registration. 653 654config DEBUG_FS_ALLOW_ALL 655 bool "Access normal" 656 help 657 No restrictions apply. Both API and filesystem registration 658 is on. This is the normal default operation. 659 660config DEBUG_FS_DISALLOW_MOUNT 661 bool "Do not register debugfs as filesystem" 662 help 663 The API is open but filesystem is not loaded. Clients can still do 664 their work and read with debug tools that do not need 665 debugfs filesystem. 666 667config DEBUG_FS_ALLOW_NONE 668 bool "No access" 669 help 670 Access is off. Clients get -PERM when trying to create nodes in 671 debugfs tree and debugfs is not registered as a filesystem. 672 Client can then back-off or continue without debugfs access. 673 674endchoice 675 676source "lib/Kconfig.kgdb" 677source "lib/Kconfig.ubsan" 678source "lib/Kconfig.kcsan" 679 680endmenu 681 682menu "Networking Debugging" 683 684source "net/Kconfig.debug" 685 686endmenu # "Networking Debugging" 687 688menu "Memory Debugging" 689 690source "mm/Kconfig.debug" 691 692config DEBUG_OBJECTS 693 bool "Debug object operations" 694 depends on DEBUG_KERNEL 695 help 696 If you say Y here, additional code will be inserted into the 697 kernel to track the life time of various objects and validate 698 the operations on those objects. 699 700config DEBUG_OBJECTS_SELFTEST 701 bool "Debug objects selftest" 702 depends on DEBUG_OBJECTS 703 help 704 This enables the selftest of the object debug code. 705 706config DEBUG_OBJECTS_FREE 707 bool "Debug objects in freed memory" 708 depends on DEBUG_OBJECTS 709 help 710 This enables checks whether a k/v free operation frees an area 711 which contains an object which has not been deactivated 712 properly. This can make kmalloc/kfree-intensive workloads 713 much slower. 714 715config DEBUG_OBJECTS_TIMERS 716 bool "Debug timer objects" 717 depends on DEBUG_OBJECTS 718 help 719 If you say Y here, additional code will be inserted into the 720 timer routines to track the life time of timer objects and 721 validate the timer operations. 722 723config DEBUG_OBJECTS_WORK 724 bool "Debug work objects" 725 depends on DEBUG_OBJECTS 726 help 727 If you say Y here, additional code will be inserted into the 728 work queue routines to track the life time of work objects and 729 validate the work operations. 730 731config DEBUG_OBJECTS_RCU_HEAD 732 bool "Debug RCU callbacks objects" 733 depends on DEBUG_OBJECTS 734 help 735 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 736 737config DEBUG_OBJECTS_PERCPU_COUNTER 738 bool "Debug percpu counter objects" 739 depends on DEBUG_OBJECTS 740 help 741 If you say Y here, additional code will be inserted into the 742 percpu counter routines to track the life time of percpu counter 743 objects and validate the percpu counter operations. 744 745config DEBUG_OBJECTS_ENABLE_DEFAULT 746 int "debug_objects bootup default value (0-1)" 747 range 0 1 748 default "1" 749 depends on DEBUG_OBJECTS 750 help 751 Debug objects boot parameter default value 752 753config SHRINKER_DEBUG 754 bool "Enable shrinker debugging support" 755 depends on DEBUG_FS 756 help 757 Say Y to enable the shrinker debugfs interface which provides 758 visibility into the kernel memory shrinkers subsystem. 759 Disable it to avoid an extra memory footprint. 760 761config DEBUG_STACK_USAGE 762 bool "Stack utilization instrumentation" 763 depends on DEBUG_KERNEL && !IA64 764 help 765 Enables the display of the minimum amount of free stack which each 766 task has ever had available in the sysrq-T and sysrq-P debug output. 767 768 This option will slow down process creation somewhat. 769 770config SCHED_STACK_END_CHECK 771 bool "Detect stack corruption on calls to schedule()" 772 depends on DEBUG_KERNEL 773 default n 774 help 775 This option checks for a stack overrun on calls to schedule(). 776 If the stack end location is found to be over written always panic as 777 the content of the corrupted region can no longer be trusted. 778 This is to ensure no erroneous behaviour occurs which could result in 779 data corruption or a sporadic crash at a later stage once the region 780 is examined. The runtime overhead introduced is minimal. 781 782config ARCH_HAS_DEBUG_VM_PGTABLE 783 bool 784 help 785 An architecture should select this when it can successfully 786 build and run DEBUG_VM_PGTABLE. 787 788config DEBUG_VM_IRQSOFF 789 def_bool DEBUG_VM && !PREEMPT_RT 790 791config DEBUG_VM 792 bool "Debug VM" 793 depends on DEBUG_KERNEL 794 help 795 Enable this to turn on extended checks in the virtual-memory system 796 that may impact performance. 797 798 If unsure, say N. 799 800config DEBUG_VM_SHOOT_LAZIES 801 bool "Debug MMU_LAZY_TLB_SHOOTDOWN implementation" 802 depends on DEBUG_VM 803 depends on MMU_LAZY_TLB_SHOOTDOWN 804 help 805 Enable additional IPIs that ensure lazy tlb mm references are removed 806 before the mm is freed. 807 808 If unsure, say N. 809 810config DEBUG_VM_MAPLE_TREE 811 bool "Debug VM maple trees" 812 depends on DEBUG_VM 813 select DEBUG_MAPLE_TREE 814 help 815 Enable VM maple tree debugging information and extra validations. 816 817 If unsure, say N. 818 819config DEBUG_VM_RB 820 bool "Debug VM red-black trees" 821 depends on DEBUG_VM 822 help 823 Enable VM red-black tree debugging information and extra validations. 824 825 If unsure, say N. 826 827config DEBUG_VM_PGFLAGS 828 bool "Debug page-flags operations" 829 depends on DEBUG_VM 830 help 831 Enables extra validation on page flags operations. 832 833 If unsure, say N. 834 835config DEBUG_VM_PGTABLE 836 bool "Debug arch page table for semantics compliance" 837 depends on MMU 838 depends on ARCH_HAS_DEBUG_VM_PGTABLE 839 default y if DEBUG_VM 840 help 841 This option provides a debug method which can be used to test 842 architecture page table helper functions on various platforms in 843 verifying if they comply with expected generic MM semantics. This 844 will help architecture code in making sure that any changes or 845 new additions of these helpers still conform to expected 846 semantics of the generic MM. Platforms will have to opt in for 847 this through ARCH_HAS_DEBUG_VM_PGTABLE. 848 849 If unsure, say N. 850 851config ARCH_HAS_DEBUG_VIRTUAL 852 bool 853 854config DEBUG_VIRTUAL 855 bool "Debug VM translations" 856 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 857 help 858 Enable some costly sanity checks in virtual to page code. This can 859 catch mistakes with virt_to_page() and friends. 860 861 If unsure, say N. 862 863config DEBUG_NOMMU_REGIONS 864 bool "Debug the global anon/private NOMMU mapping region tree" 865 depends on DEBUG_KERNEL && !MMU 866 help 867 This option causes the global tree of anonymous and private mapping 868 regions to be regularly checked for invalid topology. 869 870config DEBUG_MEMORY_INIT 871 bool "Debug memory initialisation" if EXPERT 872 default !EXPERT 873 help 874 Enable this for additional checks during memory initialisation. 875 The sanity checks verify aspects of the VM such as the memory model 876 and other information provided by the architecture. Verbose 877 information will be printed at KERN_DEBUG loglevel depending 878 on the mminit_loglevel= command-line option. 879 880 If unsure, say Y 881 882config MEMORY_NOTIFIER_ERROR_INJECT 883 tristate "Memory hotplug notifier error injection module" 884 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 885 help 886 This option provides the ability to inject artificial errors to 887 memory hotplug notifier chain callbacks. It is controlled through 888 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 889 890 If the notifier call chain should be failed with some events 891 notified, write the error code to "actions/<notifier event>/error". 892 893 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 894 895 # cd /sys/kernel/debug/notifier-error-inject/memory 896 # echo -12 > actions/MEM_GOING_OFFLINE/error 897 # echo offline > /sys/devices/system/memory/memoryXXX/state 898 bash: echo: write error: Cannot allocate memory 899 900 To compile this code as a module, choose M here: the module will 901 be called memory-notifier-error-inject. 902 903 If unsure, say N. 904 905config DEBUG_PER_CPU_MAPS 906 bool "Debug access to per_cpu maps" 907 depends on DEBUG_KERNEL 908 depends on SMP 909 help 910 Say Y to verify that the per_cpu map being accessed has 911 been set up. This adds a fair amount of code to kernel memory 912 and decreases performance. 913 914 Say N if unsure. 915 916config DEBUG_KMAP_LOCAL 917 bool "Debug kmap_local temporary mappings" 918 depends on DEBUG_KERNEL && KMAP_LOCAL 919 help 920 This option enables additional error checking for the kmap_local 921 infrastructure. Disable for production use. 922 923config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 924 bool 925 926config DEBUG_KMAP_LOCAL_FORCE_MAP 927 bool "Enforce kmap_local temporary mappings" 928 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 929 select KMAP_LOCAL 930 select DEBUG_KMAP_LOCAL 931 help 932 This option enforces temporary mappings through the kmap_local 933 mechanism for non-highmem pages and on non-highmem systems. 934 Disable this for production systems! 935 936config DEBUG_HIGHMEM 937 bool "Highmem debugging" 938 depends on DEBUG_KERNEL && HIGHMEM 939 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 940 select DEBUG_KMAP_LOCAL 941 help 942 This option enables additional error checking for high memory 943 systems. Disable for production systems. 944 945config HAVE_DEBUG_STACKOVERFLOW 946 bool 947 948config DEBUG_STACKOVERFLOW 949 bool "Check for stack overflows" 950 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 951 help 952 Say Y here if you want to check for overflows of kernel, IRQ 953 and exception stacks (if your architecture uses them). This 954 option will show detailed messages if free stack space drops 955 below a certain limit. 956 957 These kinds of bugs usually occur when call-chains in the 958 kernel get too deep, especially when interrupts are 959 involved. 960 961 Use this in cases where you see apparently random memory 962 corruption, especially if it appears in 'struct thread_info' 963 964 If in doubt, say "N". 965 966source "lib/Kconfig.kasan" 967source "lib/Kconfig.kfence" 968source "lib/Kconfig.kmsan" 969 970endmenu # "Memory Debugging" 971 972config DEBUG_SHIRQ 973 bool "Debug shared IRQ handlers" 974 depends on DEBUG_KERNEL 975 help 976 Enable this to generate a spurious interrupt just before a shared 977 interrupt handler is deregistered (generating one when registering 978 is currently disabled). Drivers need to handle this correctly. Some 979 don't and need to be caught. 980 981menu "Debug Oops, Lockups and Hangs" 982 983config PANIC_ON_OOPS 984 bool "Panic on Oops" 985 help 986 Say Y here to enable the kernel to panic when it oopses. This 987 has the same effect as setting oops=panic on the kernel command 988 line. 989 990 This feature is useful to ensure that the kernel does not do 991 anything erroneous after an oops which could result in data 992 corruption or other issues. 993 994 Say N if unsure. 995 996config PANIC_ON_OOPS_VALUE 997 int 998 range 0 1 999 default 0 if !PANIC_ON_OOPS 1000 default 1 if PANIC_ON_OOPS 1001 1002config PANIC_TIMEOUT 1003 int "panic timeout" 1004 default 0 1005 help 1006 Set the timeout value (in seconds) until a reboot occurs when 1007 the kernel panics. If n = 0, then we wait forever. A timeout 1008 value n > 0 will wait n seconds before rebooting, while a timeout 1009 value n < 0 will reboot immediately. 1010 1011config LOCKUP_DETECTOR 1012 bool 1013 1014config SOFTLOCKUP_DETECTOR 1015 bool "Detect Soft Lockups" 1016 depends on DEBUG_KERNEL && !S390 1017 select LOCKUP_DETECTOR 1018 help 1019 Say Y here to enable the kernel to act as a watchdog to detect 1020 soft lockups. 1021 1022 Softlockups are bugs that cause the kernel to loop in kernel 1023 mode for more than 20 seconds, without giving other tasks a 1024 chance to run. The current stack trace is displayed upon 1025 detection and the system will stay locked up. 1026 1027config BOOTPARAM_SOFTLOCKUP_PANIC 1028 bool "Panic (Reboot) On Soft Lockups" 1029 depends on SOFTLOCKUP_DETECTOR 1030 help 1031 Say Y here to enable the kernel to panic on "soft lockups", 1032 which are bugs that cause the kernel to loop in kernel 1033 mode for more than 20 seconds (configurable using the watchdog_thresh 1034 sysctl), without giving other tasks a chance to run. 1035 1036 The panic can be used in combination with panic_timeout, 1037 to cause the system to reboot automatically after a 1038 lockup has been detected. This feature is useful for 1039 high-availability systems that have uptime guarantees and 1040 where a lockup must be resolved ASAP. 1041 1042 Say N if unsure. 1043 1044config HAVE_HARDLOCKUP_DETECTOR_BUDDY 1045 bool 1046 depends on SMP 1047 default y 1048 1049# 1050# Global switch whether to build a hardlockup detector at all. It is available 1051# only when the architecture supports at least one implementation. There are 1052# two exceptions. The hardlockup detector is never enabled on: 1053# 1054# s390: it reported many false positives there 1055# 1056# sparc64: has a custom implementation which is not using the common 1057# hardlockup command line options and sysctl interface. 1058# 1059config HARDLOCKUP_DETECTOR 1060 bool "Detect Hard Lockups" 1061 depends on DEBUG_KERNEL && !S390 && !HARDLOCKUP_DETECTOR_SPARC64 1062 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_BUDDY || HAVE_HARDLOCKUP_DETECTOR_ARCH 1063 imply HARDLOCKUP_DETECTOR_PERF 1064 imply HARDLOCKUP_DETECTOR_BUDDY 1065 imply HARDLOCKUP_DETECTOR_ARCH 1066 select LOCKUP_DETECTOR 1067 1068 help 1069 Say Y here to enable the kernel to act as a watchdog to detect 1070 hard lockups. 1071 1072 Hardlockups are bugs that cause the CPU to loop in kernel mode 1073 for more than 10 seconds, without letting other interrupts have a 1074 chance to run. The current stack trace is displayed upon detection 1075 and the system will stay locked up. 1076 1077# 1078# Note that arch-specific variants are always preferred. 1079# 1080config HARDLOCKUP_DETECTOR_PREFER_BUDDY 1081 bool "Prefer the buddy CPU hardlockup detector" 1082 depends on HARDLOCKUP_DETECTOR 1083 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && HAVE_HARDLOCKUP_DETECTOR_BUDDY 1084 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1085 help 1086 Say Y here to prefer the buddy hardlockup detector over the perf one. 1087 1088 With the buddy detector, each CPU uses its softlockup hrtimer 1089 to check that the next CPU is processing hrtimer interrupts by 1090 verifying that a counter is increasing. 1091 1092 This hardlockup detector is useful on systems that don't have 1093 an arch-specific hardlockup detector or if resources needed 1094 for the hardlockup detector are better used for other things. 1095 1096config HARDLOCKUP_DETECTOR_PERF 1097 bool 1098 depends on HARDLOCKUP_DETECTOR 1099 depends on HAVE_HARDLOCKUP_DETECTOR_PERF && !HARDLOCKUP_DETECTOR_PREFER_BUDDY 1100 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1101 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1102 1103config HARDLOCKUP_DETECTOR_BUDDY 1104 bool 1105 depends on HARDLOCKUP_DETECTOR 1106 depends on HAVE_HARDLOCKUP_DETECTOR_BUDDY 1107 depends on !HAVE_HARDLOCKUP_DETECTOR_PERF || HARDLOCKUP_DETECTOR_PREFER_BUDDY 1108 depends on !HAVE_HARDLOCKUP_DETECTOR_ARCH 1109 select HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1110 1111config HARDLOCKUP_DETECTOR_ARCH 1112 bool 1113 depends on HARDLOCKUP_DETECTOR 1114 depends on HAVE_HARDLOCKUP_DETECTOR_ARCH 1115 help 1116 The arch-specific implementation of the hardlockup detector will 1117 be used. 1118 1119# 1120# Both the "perf" and "buddy" hardlockup detectors count hrtimer 1121# interrupts. This config enables functions managing this common code. 1122# 1123config HARDLOCKUP_DETECTOR_COUNTS_HRTIMER 1124 bool 1125 select SOFTLOCKUP_DETECTOR 1126 1127# 1128# Enables a timestamp based low pass filter to compensate for perf based 1129# hard lockup detection which runs too fast due to turbo modes. 1130# 1131config HARDLOCKUP_CHECK_TIMESTAMP 1132 bool 1133 1134config BOOTPARAM_HARDLOCKUP_PANIC 1135 bool "Panic (Reboot) On Hard Lockups" 1136 depends on HARDLOCKUP_DETECTOR 1137 help 1138 Say Y here to enable the kernel to panic on "hard lockups", 1139 which are bugs that cause the kernel to loop in kernel 1140 mode with interrupts disabled for more than 10 seconds (configurable 1141 using the watchdog_thresh sysctl). 1142 1143 Say N if unsure. 1144 1145config DETECT_HUNG_TASK 1146 bool "Detect Hung Tasks" 1147 depends on DEBUG_KERNEL 1148 default SOFTLOCKUP_DETECTOR 1149 help 1150 Say Y here to enable the kernel to detect "hung tasks", 1151 which are bugs that cause the task to be stuck in 1152 uninterruptible "D" state indefinitely. 1153 1154 When a hung task is detected, the kernel will print the 1155 current stack trace (which you should report), but the 1156 task will stay in uninterruptible state. If lockdep is 1157 enabled then all held locks will also be reported. This 1158 feature has negligible overhead. 1159 1160config DEFAULT_HUNG_TASK_TIMEOUT 1161 int "Default timeout for hung task detection (in seconds)" 1162 depends on DETECT_HUNG_TASK 1163 default 120 1164 help 1165 This option controls the default timeout (in seconds) used 1166 to determine when a task has become non-responsive and should 1167 be considered hung. 1168 1169 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1170 sysctl or by writing a value to 1171 /proc/sys/kernel/hung_task_timeout_secs. 1172 1173 A timeout of 0 disables the check. The default is two minutes. 1174 Keeping the default should be fine in most cases. 1175 1176config BOOTPARAM_HUNG_TASK_PANIC 1177 bool "Panic (Reboot) On Hung Tasks" 1178 depends on DETECT_HUNG_TASK 1179 help 1180 Say Y here to enable the kernel to panic on "hung tasks", 1181 which are bugs that cause the kernel to leave a task stuck 1182 in uninterruptible "D" state. 1183 1184 The panic can be used in combination with panic_timeout, 1185 to cause the system to reboot automatically after a 1186 hung task has been detected. This feature is useful for 1187 high-availability systems that have uptime guarantees and 1188 where a hung tasks must be resolved ASAP. 1189 1190 Say N if unsure. 1191 1192config WQ_WATCHDOG 1193 bool "Detect Workqueue Stalls" 1194 depends on DEBUG_KERNEL 1195 help 1196 Say Y here to enable stall detection on workqueues. If a 1197 worker pool doesn't make forward progress on a pending work 1198 item for over a given amount of time, 30s by default, a 1199 warning message is printed along with dump of workqueue 1200 state. This can be configured through kernel parameter 1201 "workqueue.watchdog_thresh" and its sysfs counterpart. 1202 1203config WQ_CPU_INTENSIVE_REPORT 1204 bool "Report per-cpu work items which hog CPU for too long" 1205 depends on DEBUG_KERNEL 1206 help 1207 Say Y here to enable reporting of concurrency-managed per-cpu work 1208 items that hog CPUs for longer than 1209 workqueue.cpu_intensive_thresh_us. Workqueue automatically 1210 detects and excludes them from concurrency management to prevent 1211 them from stalling other per-cpu work items. Occassional 1212 triggering may not necessarily indicate a problem. Repeated 1213 triggering likely indicates that the work item should be switched 1214 to use an unbound workqueue. 1215 1216config TEST_LOCKUP 1217 tristate "Test module to generate lockups" 1218 depends on m 1219 help 1220 This builds the "test_lockup" module that helps to make sure 1221 that watchdogs and lockup detectors are working properly. 1222 1223 Depending on module parameters it could emulate soft or hard 1224 lockup, "hung task", or locking arbitrary lock for a long time. 1225 Also it could generate series of lockups with cooling-down periods. 1226 1227 If unsure, say N. 1228 1229endmenu # "Debug lockups and hangs" 1230 1231menu "Scheduler Debugging" 1232 1233config SCHED_DEBUG 1234 bool "Collect scheduler debugging info" 1235 depends on DEBUG_KERNEL && DEBUG_FS 1236 default y 1237 help 1238 If you say Y here, the /sys/kernel/debug/sched file will be provided 1239 that can help debug the scheduler. The runtime overhead of this 1240 option is minimal. 1241 1242config SCHED_INFO 1243 bool 1244 default n 1245 1246config SCHEDSTATS 1247 bool "Collect scheduler statistics" 1248 depends on DEBUG_KERNEL && PROC_FS 1249 select SCHED_INFO 1250 help 1251 If you say Y here, additional code will be inserted into the 1252 scheduler and related routines to collect statistics about 1253 scheduler behavior and provide them in /proc/schedstat. These 1254 stats may be useful for both tuning and debugging the scheduler 1255 If you aren't debugging the scheduler or trying to tune a specific 1256 application, you can say N to avoid the very slight overhead 1257 this adds. 1258 1259endmenu 1260 1261config DEBUG_TIMEKEEPING 1262 bool "Enable extra timekeeping sanity checking" 1263 help 1264 This option will enable additional timekeeping sanity checks 1265 which may be helpful when diagnosing issues where timekeeping 1266 problems are suspected. 1267 1268 This may include checks in the timekeeping hotpaths, so this 1269 option may have a (very small) performance impact to some 1270 workloads. 1271 1272 If unsure, say N. 1273 1274config DEBUG_PREEMPT 1275 bool "Debug preemptible kernel" 1276 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1277 help 1278 If you say Y here then the kernel will use a debug variant of the 1279 commonly used smp_processor_id() function and will print warnings 1280 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1281 will detect preemption count underflows. 1282 1283 This option has potential to introduce high runtime overhead, 1284 depending on workload as it triggers debugging routines for each 1285 this_cpu operation. It should only be used for debugging purposes. 1286 1287menu "Lock Debugging (spinlocks, mutexes, etc...)" 1288 1289config LOCK_DEBUGGING_SUPPORT 1290 bool 1291 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1292 default y 1293 1294config PROVE_LOCKING 1295 bool "Lock debugging: prove locking correctness" 1296 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1297 select LOCKDEP 1298 select DEBUG_SPINLOCK 1299 select DEBUG_MUTEXES if !PREEMPT_RT 1300 select DEBUG_RT_MUTEXES if RT_MUTEXES 1301 select DEBUG_RWSEMS 1302 select DEBUG_WW_MUTEX_SLOWPATH 1303 select DEBUG_LOCK_ALLOC 1304 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1305 select TRACE_IRQFLAGS 1306 default n 1307 help 1308 This feature enables the kernel to prove that all locking 1309 that occurs in the kernel runtime is mathematically 1310 correct: that under no circumstance could an arbitrary (and 1311 not yet triggered) combination of observed locking 1312 sequences (on an arbitrary number of CPUs, running an 1313 arbitrary number of tasks and interrupt contexts) cause a 1314 deadlock. 1315 1316 In short, this feature enables the kernel to report locking 1317 related deadlocks before they actually occur. 1318 1319 The proof does not depend on how hard and complex a 1320 deadlock scenario would be to trigger: how many 1321 participant CPUs, tasks and irq-contexts would be needed 1322 for it to trigger. The proof also does not depend on 1323 timing: if a race and a resulting deadlock is possible 1324 theoretically (no matter how unlikely the race scenario 1325 is), it will be proven so and will immediately be 1326 reported by the kernel (once the event is observed that 1327 makes the deadlock theoretically possible). 1328 1329 If a deadlock is impossible (i.e. the locking rules, as 1330 observed by the kernel, are mathematically correct), the 1331 kernel reports nothing. 1332 1333 NOTE: this feature can also be enabled for rwlocks, mutexes 1334 and rwsems - in which case all dependencies between these 1335 different locking variants are observed and mapped too, and 1336 the proof of observed correctness is also maintained for an 1337 arbitrary combination of these separate locking variants. 1338 1339 For more details, see Documentation/locking/lockdep-design.rst. 1340 1341config PROVE_RAW_LOCK_NESTING 1342 bool "Enable raw_spinlock - spinlock nesting checks" 1343 depends on PROVE_LOCKING 1344 default n 1345 help 1346 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1347 that the lock nesting rules for PREEMPT_RT enabled kernels are 1348 not violated. 1349 1350 NOTE: There are known nesting problems. So if you enable this 1351 option expect lockdep splats until these problems have been fully 1352 addressed which is work in progress. This config switch allows to 1353 identify and analyze these problems. It will be removed and the 1354 check permanently enabled once the main issues have been fixed. 1355 1356 If unsure, select N. 1357 1358config LOCK_STAT 1359 bool "Lock usage statistics" 1360 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1361 select LOCKDEP 1362 select DEBUG_SPINLOCK 1363 select DEBUG_MUTEXES if !PREEMPT_RT 1364 select DEBUG_RT_MUTEXES if RT_MUTEXES 1365 select DEBUG_LOCK_ALLOC 1366 default n 1367 help 1368 This feature enables tracking lock contention points 1369 1370 For more details, see Documentation/locking/lockstat.rst 1371 1372 This also enables lock events required by "perf lock", 1373 subcommand of perf. 1374 If you want to use "perf lock", you also need to turn on 1375 CONFIG_EVENT_TRACING. 1376 1377 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1378 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1379 1380config DEBUG_RT_MUTEXES 1381 bool "RT Mutex debugging, deadlock detection" 1382 depends on DEBUG_KERNEL && RT_MUTEXES 1383 help 1384 This allows rt mutex semantics violations and rt mutex related 1385 deadlocks (lockups) to be detected and reported automatically. 1386 1387config DEBUG_SPINLOCK 1388 bool "Spinlock and rw-lock debugging: basic checks" 1389 depends on DEBUG_KERNEL 1390 select UNINLINE_SPIN_UNLOCK 1391 help 1392 Say Y here and build SMP to catch missing spinlock initialization 1393 and certain other kinds of spinlock errors commonly made. This is 1394 best used in conjunction with the NMI watchdog so that spinlock 1395 deadlocks are also debuggable. 1396 1397config DEBUG_MUTEXES 1398 bool "Mutex debugging: basic checks" 1399 depends on DEBUG_KERNEL && !PREEMPT_RT 1400 help 1401 This feature allows mutex semantics violations to be detected and 1402 reported. 1403 1404config DEBUG_WW_MUTEX_SLOWPATH 1405 bool "Wait/wound mutex debugging: Slowpath testing" 1406 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1407 select DEBUG_LOCK_ALLOC 1408 select DEBUG_SPINLOCK 1409 select DEBUG_MUTEXES if !PREEMPT_RT 1410 select DEBUG_RT_MUTEXES if PREEMPT_RT 1411 help 1412 This feature enables slowpath testing for w/w mutex users by 1413 injecting additional -EDEADLK wound/backoff cases. Together with 1414 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1415 will test all possible w/w mutex interface abuse with the 1416 exception of simply not acquiring all the required locks. 1417 Note that this feature can introduce significant overhead, so 1418 it really should not be enabled in a production or distro kernel, 1419 even a debug kernel. If you are a driver writer, enable it. If 1420 you are a distro, do not. 1421 1422config DEBUG_RWSEMS 1423 bool "RW Semaphore debugging: basic checks" 1424 depends on DEBUG_KERNEL 1425 help 1426 This debugging feature allows mismatched rw semaphore locks 1427 and unlocks to be detected and reported. 1428 1429config DEBUG_LOCK_ALLOC 1430 bool "Lock debugging: detect incorrect freeing of live locks" 1431 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1432 select DEBUG_SPINLOCK 1433 select DEBUG_MUTEXES if !PREEMPT_RT 1434 select DEBUG_RT_MUTEXES if RT_MUTEXES 1435 select LOCKDEP 1436 help 1437 This feature will check whether any held lock (spinlock, rwlock, 1438 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1439 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1440 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1441 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1442 held during task exit. 1443 1444config LOCKDEP 1445 bool 1446 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1447 select STACKTRACE 1448 select KALLSYMS 1449 select KALLSYMS_ALL 1450 1451config LOCKDEP_SMALL 1452 bool 1453 1454config LOCKDEP_BITS 1455 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1456 depends on LOCKDEP && !LOCKDEP_SMALL 1457 range 10 30 1458 default 15 1459 help 1460 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1461 1462config LOCKDEP_CHAINS_BITS 1463 int "Bitsize for MAX_LOCKDEP_CHAINS" 1464 depends on LOCKDEP && !LOCKDEP_SMALL 1465 range 10 30 1466 default 16 1467 help 1468 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1469 1470config LOCKDEP_STACK_TRACE_BITS 1471 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1472 depends on LOCKDEP && !LOCKDEP_SMALL 1473 range 10 30 1474 default 19 1475 help 1476 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1477 1478config LOCKDEP_STACK_TRACE_HASH_BITS 1479 int "Bitsize for STACK_TRACE_HASH_SIZE" 1480 depends on LOCKDEP && !LOCKDEP_SMALL 1481 range 10 30 1482 default 14 1483 help 1484 Try increasing this value if you need large STACK_TRACE_HASH_SIZE. 1485 1486config LOCKDEP_CIRCULAR_QUEUE_BITS 1487 int "Bitsize for elements in circular_queue struct" 1488 depends on LOCKDEP 1489 range 10 30 1490 default 12 1491 help 1492 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1493 1494config DEBUG_LOCKDEP 1495 bool "Lock dependency engine debugging" 1496 depends on DEBUG_KERNEL && LOCKDEP 1497 select DEBUG_IRQFLAGS 1498 help 1499 If you say Y here, the lock dependency engine will do 1500 additional runtime checks to debug itself, at the price 1501 of more runtime overhead. 1502 1503config DEBUG_ATOMIC_SLEEP 1504 bool "Sleep inside atomic section checking" 1505 select PREEMPT_COUNT 1506 depends on DEBUG_KERNEL 1507 depends on !ARCH_NO_PREEMPT 1508 help 1509 If you say Y here, various routines which may sleep will become very 1510 noisy if they are called inside atomic sections: when a spinlock is 1511 held, inside an rcu read side critical section, inside preempt disabled 1512 sections, inside an interrupt, etc... 1513 1514config DEBUG_LOCKING_API_SELFTESTS 1515 bool "Locking API boot-time self-tests" 1516 depends on DEBUG_KERNEL 1517 help 1518 Say Y here if you want the kernel to run a short self-test during 1519 bootup. The self-test checks whether common types of locking bugs 1520 are detected by debugging mechanisms or not. (if you disable 1521 lock debugging then those bugs won't be detected of course.) 1522 The following locking APIs are covered: spinlocks, rwlocks, 1523 mutexes and rwsems. 1524 1525config LOCK_TORTURE_TEST 1526 tristate "torture tests for locking" 1527 depends on DEBUG_KERNEL 1528 select TORTURE_TEST 1529 help 1530 This option provides a kernel module that runs torture tests 1531 on kernel locking primitives. The kernel module may be built 1532 after the fact on the running kernel to be tested, if desired. 1533 1534 Say Y here if you want kernel locking-primitive torture tests 1535 to be built into the kernel. 1536 Say M if you want these torture tests to build as a module. 1537 Say N if you are unsure. 1538 1539config WW_MUTEX_SELFTEST 1540 tristate "Wait/wound mutex selftests" 1541 help 1542 This option provides a kernel module that runs tests on the 1543 on the struct ww_mutex locking API. 1544 1545 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1546 with this test harness. 1547 1548 Say M if you want these self tests to build as a module. 1549 Say N if you are unsure. 1550 1551config SCF_TORTURE_TEST 1552 tristate "torture tests for smp_call_function*()" 1553 depends on DEBUG_KERNEL 1554 select TORTURE_TEST 1555 help 1556 This option provides a kernel module that runs torture tests 1557 on the smp_call_function() family of primitives. The kernel 1558 module may be built after the fact on the running kernel to 1559 be tested, if desired. 1560 1561config CSD_LOCK_WAIT_DEBUG 1562 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1563 depends on DEBUG_KERNEL 1564 depends on 64BIT 1565 default n 1566 help 1567 This option enables debug prints when CPUs are slow to respond 1568 to the smp_call_function*() IPI wrappers. These debug prints 1569 include the IPI handler function currently executing (if any) 1570 and relevant stack traces. 1571 1572config CSD_LOCK_WAIT_DEBUG_DEFAULT 1573 bool "Default csd_lock_wait() debugging on at boot time" 1574 depends on CSD_LOCK_WAIT_DEBUG 1575 depends on 64BIT 1576 default n 1577 help 1578 This option causes the csdlock_debug= kernel boot parameter to 1579 default to 1 (basic debugging) instead of 0 (no debugging). 1580 1581endmenu # lock debugging 1582 1583config TRACE_IRQFLAGS 1584 depends on TRACE_IRQFLAGS_SUPPORT 1585 bool 1586 help 1587 Enables hooks to interrupt enabling and disabling for 1588 either tracing or lock debugging. 1589 1590config TRACE_IRQFLAGS_NMI 1591 def_bool y 1592 depends on TRACE_IRQFLAGS 1593 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1594 1595config NMI_CHECK_CPU 1596 bool "Debugging for CPUs failing to respond to backtrace requests" 1597 depends on DEBUG_KERNEL 1598 depends on X86 1599 default n 1600 help 1601 Enables debug prints when a CPU fails to respond to a given 1602 backtrace NMI. These prints provide some reasons why a CPU 1603 might legitimately be failing to respond, for example, if it 1604 is offline of if ignore_nmis is set. 1605 1606config DEBUG_IRQFLAGS 1607 bool "Debug IRQ flag manipulation" 1608 help 1609 Enables checks for potentially unsafe enabling or disabling of 1610 interrupts, such as calling raw_local_irq_restore() when interrupts 1611 are enabled. 1612 1613config STACKTRACE 1614 bool "Stack backtrace support" 1615 depends on STACKTRACE_SUPPORT 1616 help 1617 This option causes the kernel to create a /proc/pid/stack for 1618 every process, showing its current stack trace. 1619 It is also used by various kernel debugging features that require 1620 stack trace generation. 1621 1622config WARN_ALL_UNSEEDED_RANDOM 1623 bool "Warn for all uses of unseeded randomness" 1624 default n 1625 help 1626 Some parts of the kernel contain bugs relating to their use of 1627 cryptographically secure random numbers before it's actually possible 1628 to generate those numbers securely. This setting ensures that these 1629 flaws don't go unnoticed, by enabling a message, should this ever 1630 occur. This will allow people with obscure setups to know when things 1631 are going wrong, so that they might contact developers about fixing 1632 it. 1633 1634 Unfortunately, on some models of some architectures getting 1635 a fully seeded CRNG is extremely difficult, and so this can 1636 result in dmesg getting spammed for a surprisingly long 1637 time. This is really bad from a security perspective, and 1638 so architecture maintainers really need to do what they can 1639 to get the CRNG seeded sooner after the system is booted. 1640 However, since users cannot do anything actionable to 1641 address this, by default this option is disabled. 1642 1643 Say Y here if you want to receive warnings for all uses of 1644 unseeded randomness. This will be of use primarily for 1645 those developers interested in improving the security of 1646 Linux kernels running on their architecture (or 1647 subarchitecture). 1648 1649config DEBUG_KOBJECT 1650 bool "kobject debugging" 1651 depends on DEBUG_KERNEL 1652 help 1653 If you say Y here, some extra kobject debugging messages will be sent 1654 to the syslog. 1655 1656config DEBUG_KOBJECT_RELEASE 1657 bool "kobject release debugging" 1658 depends on DEBUG_OBJECTS_TIMERS 1659 help 1660 kobjects are reference counted objects. This means that their 1661 last reference count put is not predictable, and the kobject can 1662 live on past the point at which a driver decides to drop its 1663 initial reference to the kobject gained on allocation. An 1664 example of this would be a struct device which has just been 1665 unregistered. 1666 1667 However, some buggy drivers assume that after such an operation, 1668 the memory backing the kobject can be immediately freed. This 1669 goes completely against the principles of a refcounted object. 1670 1671 If you say Y here, the kernel will delay the release of kobjects 1672 on the last reference count to improve the visibility of this 1673 kind of kobject release bug. 1674 1675config HAVE_DEBUG_BUGVERBOSE 1676 bool 1677 1678menu "Debug kernel data structures" 1679 1680config DEBUG_LIST 1681 bool "Debug linked list manipulation" 1682 depends on DEBUG_KERNEL 1683 select LIST_HARDENED 1684 help 1685 Enable this to turn on extended checks in the linked-list walking 1686 routines. 1687 1688 This option trades better quality error reports for performance, and 1689 is more suitable for kernel debugging. If you care about performance, 1690 you should only enable CONFIG_LIST_HARDENED instead. 1691 1692 If unsure, say N. 1693 1694config DEBUG_PLIST 1695 bool "Debug priority linked list manipulation" 1696 depends on DEBUG_KERNEL 1697 help 1698 Enable this to turn on extended checks in the priority-ordered 1699 linked-list (plist) walking routines. This checks the entire 1700 list multiple times during each manipulation. 1701 1702 If unsure, say N. 1703 1704config DEBUG_SG 1705 bool "Debug SG table operations" 1706 depends on DEBUG_KERNEL 1707 help 1708 Enable this to turn on checks on scatter-gather tables. This can 1709 help find problems with drivers that do not properly initialize 1710 their sg tables. 1711 1712 If unsure, say N. 1713 1714config DEBUG_NOTIFIERS 1715 bool "Debug notifier call chains" 1716 depends on DEBUG_KERNEL 1717 help 1718 Enable this to turn on sanity checking for notifier call chains. 1719 This is most useful for kernel developers to make sure that 1720 modules properly unregister themselves from notifier chains. 1721 This is a relatively cheap check but if you care about maximum 1722 performance, say N. 1723 1724config DEBUG_MAPLE_TREE 1725 bool "Debug maple trees" 1726 depends on DEBUG_KERNEL 1727 help 1728 Enable maple tree debugging information and extra validations. 1729 1730 If unsure, say N. 1731 1732endmenu 1733 1734source "kernel/rcu/Kconfig.debug" 1735 1736config DEBUG_WQ_FORCE_RR_CPU 1737 bool "Force round-robin CPU selection for unbound work items" 1738 depends on DEBUG_KERNEL 1739 default n 1740 help 1741 Workqueue used to implicitly guarantee that work items queued 1742 without explicit CPU specified are put on the local CPU. This 1743 guarantee is no longer true and while local CPU is still 1744 preferred work items may be put on foreign CPUs. Kernel 1745 parameter "workqueue.debug_force_rr_cpu" is added to force 1746 round-robin CPU selection to flush out usages which depend on the 1747 now broken guarantee. This config option enables the debug 1748 feature by default. When enabled, memory and cache locality will 1749 be impacted. 1750 1751config CPU_HOTPLUG_STATE_CONTROL 1752 bool "Enable CPU hotplug state control" 1753 depends on DEBUG_KERNEL 1754 depends on HOTPLUG_CPU 1755 default n 1756 help 1757 Allows to write steps between "offline" and "online" to the CPUs 1758 sysfs target file so states can be stepped granular. This is a debug 1759 option for now as the hotplug machinery cannot be stopped and 1760 restarted at arbitrary points yet. 1761 1762 Say N if your are unsure. 1763 1764config LATENCYTOP 1765 bool "Latency measuring infrastructure" 1766 depends on DEBUG_KERNEL 1767 depends on STACKTRACE_SUPPORT 1768 depends on PROC_FS 1769 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1770 select KALLSYMS 1771 select KALLSYMS_ALL 1772 select STACKTRACE 1773 select SCHEDSTATS 1774 help 1775 Enable this option if you want to use the LatencyTOP tool 1776 to find out which userspace is blocking on what kernel operations. 1777 1778config DEBUG_CGROUP_REF 1779 bool "Disable inlining of cgroup css reference count functions" 1780 depends on DEBUG_KERNEL 1781 depends on CGROUPS 1782 depends on KPROBES 1783 default n 1784 help 1785 Force cgroup css reference count functions to not be inlined so 1786 that they can be kprobed for debugging. 1787 1788source "kernel/trace/Kconfig" 1789 1790config PROVIDE_OHCI1394_DMA_INIT 1791 bool "Remote debugging over FireWire early on boot" 1792 depends on PCI && X86 1793 help 1794 If you want to debug problems which hang or crash the kernel early 1795 on boot and the crashing machine has a FireWire port, you can use 1796 this feature to remotely access the memory of the crashed machine 1797 over FireWire. This employs remote DMA as part of the OHCI1394 1798 specification which is now the standard for FireWire controllers. 1799 1800 With remote DMA, you can monitor the printk buffer remotely using 1801 firescope and access all memory below 4GB using fireproxy from gdb. 1802 Even controlling a kernel debugger is possible using remote DMA. 1803 1804 Usage: 1805 1806 If ohci1394_dma=early is used as boot parameter, it will initialize 1807 all OHCI1394 controllers which are found in the PCI config space. 1808 1809 As all changes to the FireWire bus such as enabling and disabling 1810 devices cause a bus reset and thereby disable remote DMA for all 1811 devices, be sure to have the cable plugged and FireWire enabled on 1812 the debugging host before booting the debug target for debugging. 1813 1814 This code (~1k) is freed after boot. By then, the firewire stack 1815 in charge of the OHCI-1394 controllers should be used instead. 1816 1817 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1818 1819source "samples/Kconfig" 1820 1821config ARCH_HAS_DEVMEM_IS_ALLOWED 1822 bool 1823 1824config STRICT_DEVMEM 1825 bool "Filter access to /dev/mem" 1826 depends on MMU && DEVMEM 1827 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1828 default y if PPC || X86 || ARM64 1829 help 1830 If this option is disabled, you allow userspace (root) access to all 1831 of memory, including kernel and userspace memory. Accidental 1832 access to this is obviously disastrous, but specific access can 1833 be used by people debugging the kernel. Note that with PAT support 1834 enabled, even in this case there are restrictions on /dev/mem 1835 use due to the cache aliasing requirements. 1836 1837 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1838 file only allows userspace access to PCI space and the BIOS code and 1839 data regions. This is sufficient for dosemu and X and all common 1840 users of /dev/mem. 1841 1842 If in doubt, say Y. 1843 1844config IO_STRICT_DEVMEM 1845 bool "Filter I/O access to /dev/mem" 1846 depends on STRICT_DEVMEM 1847 help 1848 If this option is disabled, you allow userspace (root) access to all 1849 io-memory regardless of whether a driver is actively using that 1850 range. Accidental access to this is obviously disastrous, but 1851 specific access can be used by people debugging kernel drivers. 1852 1853 If this option is switched on, the /dev/mem file only allows 1854 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1855 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1856 if the driver using a given range cannot be disabled. 1857 1858 If in doubt, say Y. 1859 1860menu "$(SRCARCH) Debugging" 1861 1862source "arch/$(SRCARCH)/Kconfig.debug" 1863 1864endmenu 1865 1866menu "Kernel Testing and Coverage" 1867 1868source "lib/kunit/Kconfig" 1869 1870config NOTIFIER_ERROR_INJECTION 1871 tristate "Notifier error injection" 1872 depends on DEBUG_KERNEL 1873 select DEBUG_FS 1874 help 1875 This option provides the ability to inject artificial errors to 1876 specified notifier chain callbacks. It is useful to test the error 1877 handling of notifier call chain failures. 1878 1879 Say N if unsure. 1880 1881config PM_NOTIFIER_ERROR_INJECT 1882 tristate "PM notifier error injection module" 1883 depends on PM && NOTIFIER_ERROR_INJECTION 1884 default m if PM_DEBUG 1885 help 1886 This option provides the ability to inject artificial errors to 1887 PM notifier chain callbacks. It is controlled through debugfs 1888 interface /sys/kernel/debug/notifier-error-inject/pm 1889 1890 If the notifier call chain should be failed with some events 1891 notified, write the error code to "actions/<notifier event>/error". 1892 1893 Example: Inject PM suspend error (-12 = -ENOMEM) 1894 1895 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1896 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1897 # echo mem > /sys/power/state 1898 bash: echo: write error: Cannot allocate memory 1899 1900 To compile this code as a module, choose M here: the module will 1901 be called pm-notifier-error-inject. 1902 1903 If unsure, say N. 1904 1905config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1906 tristate "OF reconfig notifier error injection module" 1907 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1908 help 1909 This option provides the ability to inject artificial errors to 1910 OF reconfig notifier chain callbacks. It is controlled 1911 through debugfs interface under 1912 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1913 1914 If the notifier call chain should be failed with some events 1915 notified, write the error code to "actions/<notifier event>/error". 1916 1917 To compile this code as a module, choose M here: the module will 1918 be called of-reconfig-notifier-error-inject. 1919 1920 If unsure, say N. 1921 1922config NETDEV_NOTIFIER_ERROR_INJECT 1923 tristate "Netdev notifier error injection module" 1924 depends on NET && NOTIFIER_ERROR_INJECTION 1925 help 1926 This option provides the ability to inject artificial errors to 1927 netdevice notifier chain callbacks. It is controlled through debugfs 1928 interface /sys/kernel/debug/notifier-error-inject/netdev 1929 1930 If the notifier call chain should be failed with some events 1931 notified, write the error code to "actions/<notifier event>/error". 1932 1933 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1934 1935 # cd /sys/kernel/debug/notifier-error-inject/netdev 1936 # echo -22 > actions/NETDEV_CHANGEMTU/error 1937 # ip link set eth0 mtu 1024 1938 RTNETLINK answers: Invalid argument 1939 1940 To compile this code as a module, choose M here: the module will 1941 be called netdev-notifier-error-inject. 1942 1943 If unsure, say N. 1944 1945config FUNCTION_ERROR_INJECTION 1946 bool "Fault-injections of functions" 1947 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1948 help 1949 Add fault injections into various functions that are annotated with 1950 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1951 value of these functions. This is useful to test error paths of code. 1952 1953 If unsure, say N 1954 1955config FAULT_INJECTION 1956 bool "Fault-injection framework" 1957 depends on DEBUG_KERNEL 1958 help 1959 Provide fault-injection framework. 1960 For more details, see Documentation/fault-injection/. 1961 1962config FAILSLAB 1963 bool "Fault-injection capability for kmalloc" 1964 depends on FAULT_INJECTION 1965 depends on SLAB || SLUB 1966 help 1967 Provide fault-injection capability for kmalloc. 1968 1969config FAIL_PAGE_ALLOC 1970 bool "Fault-injection capability for alloc_pages()" 1971 depends on FAULT_INJECTION 1972 help 1973 Provide fault-injection capability for alloc_pages(). 1974 1975config FAULT_INJECTION_USERCOPY 1976 bool "Fault injection capability for usercopy functions" 1977 depends on FAULT_INJECTION 1978 help 1979 Provides fault-injection capability to inject failures 1980 in usercopy functions (copy_from_user(), get_user(), ...). 1981 1982config FAIL_MAKE_REQUEST 1983 bool "Fault-injection capability for disk IO" 1984 depends on FAULT_INJECTION && BLOCK 1985 help 1986 Provide fault-injection capability for disk IO. 1987 1988config FAIL_IO_TIMEOUT 1989 bool "Fault-injection capability for faking disk interrupts" 1990 depends on FAULT_INJECTION && BLOCK 1991 help 1992 Provide fault-injection capability on end IO handling. This 1993 will make the block layer "forget" an interrupt as configured, 1994 thus exercising the error handling. 1995 1996 Only works with drivers that use the generic timeout handling, 1997 for others it won't do anything. 1998 1999config FAIL_FUTEX 2000 bool "Fault-injection capability for futexes" 2001 select DEBUG_FS 2002 depends on FAULT_INJECTION && FUTEX 2003 help 2004 Provide fault-injection capability for futexes. 2005 2006config FAULT_INJECTION_DEBUG_FS 2007 bool "Debugfs entries for fault-injection capabilities" 2008 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 2009 help 2010 Enable configuration of fault-injection capabilities via debugfs. 2011 2012config FAIL_FUNCTION 2013 bool "Fault-injection capability for functions" 2014 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 2015 help 2016 Provide function-based fault-injection capability. 2017 This will allow you to override a specific function with a return 2018 with given return value. As a result, function caller will see 2019 an error value and have to handle it. This is useful to test the 2020 error handling in various subsystems. 2021 2022config FAIL_MMC_REQUEST 2023 bool "Fault-injection capability for MMC IO" 2024 depends on FAULT_INJECTION_DEBUG_FS && MMC 2025 help 2026 Provide fault-injection capability for MMC IO. 2027 This will make the mmc core return data errors. This is 2028 useful to test the error handling in the mmc block device 2029 and to test how the mmc host driver handles retries from 2030 the block device. 2031 2032config FAIL_SUNRPC 2033 bool "Fault-injection capability for SunRPC" 2034 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2035 help 2036 Provide fault-injection capability for SunRPC and 2037 its consumers. 2038 2039config FAULT_INJECTION_CONFIGFS 2040 bool "Configfs interface for fault-injection capabilities" 2041 depends on FAULT_INJECTION 2042 select CONFIGFS_FS 2043 help 2044 This option allows configfs-based drivers to dynamically configure 2045 fault-injection via configfs. Each parameter for driver-specific 2046 fault-injection can be made visible as a configfs attribute in a 2047 configfs group. 2048 2049 2050config FAULT_INJECTION_STACKTRACE_FILTER 2051 bool "stacktrace filter for fault-injection capabilities" 2052 depends on FAULT_INJECTION 2053 depends on (FAULT_INJECTION_DEBUG_FS || FAULT_INJECTION_CONFIGFS) && STACKTRACE_SUPPORT 2054 select STACKTRACE 2055 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2056 help 2057 Provide stacktrace filter for fault-injection capabilities 2058 2059config ARCH_HAS_KCOV 2060 bool 2061 help 2062 An architecture should select this when it can successfully 2063 build and run with CONFIG_KCOV. This typically requires 2064 disabling instrumentation for some early boot code. 2065 2066config CC_HAS_SANCOV_TRACE_PC 2067 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2068 2069 2070config KCOV 2071 bool "Code coverage for fuzzing" 2072 depends on ARCH_HAS_KCOV 2073 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2074 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2075 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2076 select DEBUG_FS 2077 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2078 select OBJTOOL if HAVE_NOINSTR_HACK 2079 help 2080 KCOV exposes kernel code coverage information in a form suitable 2081 for coverage-guided fuzzing (randomized testing). 2082 2083 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2084 different machines and across reboots. If you need stable PC values, 2085 disable RANDOMIZE_BASE. 2086 2087 For more details, see Documentation/dev-tools/kcov.rst. 2088 2089config KCOV_ENABLE_COMPARISONS 2090 bool "Enable comparison operands collection by KCOV" 2091 depends on KCOV 2092 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2093 help 2094 KCOV also exposes operands of every comparison in the instrumented 2095 code along with operand sizes and PCs of the comparison instructions. 2096 These operands can be used by fuzzing engines to improve the quality 2097 of fuzzing coverage. 2098 2099config KCOV_INSTRUMENT_ALL 2100 bool "Instrument all code by default" 2101 depends on KCOV 2102 default y 2103 help 2104 If you are doing generic system call fuzzing (like e.g. syzkaller), 2105 then you will want to instrument the whole kernel and you should 2106 say y here. If you are doing more targeted fuzzing (like e.g. 2107 filesystem fuzzing with AFL) then you will want to enable coverage 2108 for more specific subsets of files, and should say n here. 2109 2110config KCOV_IRQ_AREA_SIZE 2111 hex "Size of interrupt coverage collection area in words" 2112 depends on KCOV 2113 default 0x40000 2114 help 2115 KCOV uses preallocated per-cpu areas to collect coverage from 2116 soft interrupts. This specifies the size of those areas in the 2117 number of unsigned long words. 2118 2119menuconfig RUNTIME_TESTING_MENU 2120 bool "Runtime Testing" 2121 def_bool y 2122 2123if RUNTIME_TESTING_MENU 2124 2125config TEST_DHRY 2126 tristate "Dhrystone benchmark test" 2127 help 2128 Enable this to include the Dhrystone 2.1 benchmark. This test 2129 calculates the number of Dhrystones per second, and the number of 2130 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided 2131 by 1757 (the number of Dhrystones per second obtained on the VAX 2132 11/780, nominally a 1 MIPS machine). 2133 2134 To run the benchmark, it needs to be enabled explicitly, either from 2135 the kernel command line (when built-in), or from userspace (when 2136 built-in or modular. 2137 2138 Run once during kernel boot: 2139 2140 test_dhry.run 2141 2142 Set number of iterations from kernel command line: 2143 2144 test_dhry.iterations=<n> 2145 2146 Set number of iterations from userspace: 2147 2148 echo <n> > /sys/module/test_dhry/parameters/iterations 2149 2150 Trigger manual run from userspace: 2151 2152 echo y > /sys/module/test_dhry/parameters/run 2153 2154 If the number of iterations is <= 0, the test will devise a suitable 2155 number of iterations (test runs for at least 2s) automatically. 2156 This process takes ca. 4s. 2157 2158 If unsure, say N. 2159 2160config LKDTM 2161 tristate "Linux Kernel Dump Test Tool Module" 2162 depends on DEBUG_FS 2163 help 2164 This module enables testing of the different dumping mechanisms by 2165 inducing system failures at predefined crash points. 2166 If you don't need it: say N 2167 Choose M here to compile this code as a module. The module will be 2168 called lkdtm. 2169 2170 Documentation on how to use the module can be found in 2171 Documentation/fault-injection/provoke-crashes.rst 2172 2173config CPUMASK_KUNIT_TEST 2174 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2175 depends on KUNIT 2176 default KUNIT_ALL_TESTS 2177 help 2178 Enable to turn on cpumask tests, running at boot or module load time. 2179 2180 For more information on KUnit and unit tests in general, please refer 2181 to the KUnit documentation in Documentation/dev-tools/kunit/. 2182 2183 If unsure, say N. 2184 2185config TEST_LIST_SORT 2186 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2187 depends on KUNIT 2188 default KUNIT_ALL_TESTS 2189 help 2190 Enable this to turn on 'list_sort()' function test. This test is 2191 executed only once during system boot (so affects only boot time), 2192 or at module load time. 2193 2194 If unsure, say N. 2195 2196config TEST_MIN_HEAP 2197 tristate "Min heap test" 2198 depends on DEBUG_KERNEL || m 2199 help 2200 Enable this to turn on min heap function tests. This test is 2201 executed only once during system boot (so affects only boot time), 2202 or at module load time. 2203 2204 If unsure, say N. 2205 2206config TEST_SORT 2207 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2208 depends on KUNIT 2209 default KUNIT_ALL_TESTS 2210 help 2211 This option enables the self-test function of 'sort()' at boot, 2212 or at module load time. 2213 2214 If unsure, say N. 2215 2216config TEST_DIV64 2217 tristate "64bit/32bit division and modulo test" 2218 depends on DEBUG_KERNEL || m 2219 help 2220 Enable this to turn on 'do_div()' function test. This test is 2221 executed only once during system boot (so affects only boot time), 2222 or at module load time. 2223 2224 If unsure, say N. 2225 2226config TEST_IOV_ITER 2227 tristate "Test iov_iter operation" if !KUNIT_ALL_TESTS 2228 depends on KUNIT 2229 depends on MMU 2230 default KUNIT_ALL_TESTS 2231 help 2232 Enable this to turn on testing of the operation of the I/O iterator 2233 (iov_iter). This test is executed only once during system boot (so 2234 affects only boot time), or at module load time. 2235 2236 If unsure, say N. 2237 2238config KPROBES_SANITY_TEST 2239 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2240 depends on DEBUG_KERNEL 2241 depends on KPROBES 2242 depends on KUNIT 2243 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2244 default KUNIT_ALL_TESTS 2245 help 2246 This option provides for testing basic kprobes functionality on 2247 boot. Samples of kprobe and kretprobe are inserted and 2248 verified for functionality. 2249 2250 Say N if you are unsure. 2251 2252config FPROBE_SANITY_TEST 2253 bool "Self test for fprobe" 2254 depends on DEBUG_KERNEL 2255 depends on FPROBE 2256 depends on KUNIT=y 2257 help 2258 This option will enable testing the fprobe when the system boot. 2259 A series of tests are made to verify that the fprobe is functioning 2260 properly. 2261 2262 Say N if you are unsure. 2263 2264config BACKTRACE_SELF_TEST 2265 tristate "Self test for the backtrace code" 2266 depends on DEBUG_KERNEL 2267 help 2268 This option provides a kernel module that can be used to test 2269 the kernel stack backtrace code. This option is not useful 2270 for distributions or general kernels, but only for kernel 2271 developers working on architecture code. 2272 2273 Note that if you want to also test saved backtraces, you will 2274 have to enable STACKTRACE as well. 2275 2276 Say N if you are unsure. 2277 2278config TEST_REF_TRACKER 2279 tristate "Self test for reference tracker" 2280 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2281 select REF_TRACKER 2282 help 2283 This option provides a kernel module performing tests 2284 using reference tracker infrastructure. 2285 2286 Say N if you are unsure. 2287 2288config RBTREE_TEST 2289 tristate "Red-Black tree test" 2290 depends on DEBUG_KERNEL 2291 help 2292 A benchmark measuring the performance of the rbtree library. 2293 Also includes rbtree invariant checks. 2294 2295config REED_SOLOMON_TEST 2296 tristate "Reed-Solomon library test" 2297 depends on DEBUG_KERNEL || m 2298 select REED_SOLOMON 2299 select REED_SOLOMON_ENC16 2300 select REED_SOLOMON_DEC16 2301 help 2302 This option enables the self-test function of rslib at boot, 2303 or at module load time. 2304 2305 If unsure, say N. 2306 2307config INTERVAL_TREE_TEST 2308 tristate "Interval tree test" 2309 depends on DEBUG_KERNEL 2310 select INTERVAL_TREE 2311 help 2312 A benchmark measuring the performance of the interval tree library 2313 2314config PERCPU_TEST 2315 tristate "Per cpu operations test" 2316 depends on m && DEBUG_KERNEL 2317 help 2318 Enable this option to build test module which validates per-cpu 2319 operations. 2320 2321 If unsure, say N. 2322 2323config ATOMIC64_SELFTEST 2324 tristate "Perform an atomic64_t self-test" 2325 help 2326 Enable this option to test the atomic64_t functions at boot or 2327 at module load time. 2328 2329 If unsure, say N. 2330 2331config ASYNC_RAID6_TEST 2332 tristate "Self test for hardware accelerated raid6 recovery" 2333 depends on ASYNC_RAID6_RECOV 2334 select ASYNC_MEMCPY 2335 help 2336 This is a one-shot self test that permutes through the 2337 recovery of all the possible two disk failure scenarios for a 2338 N-disk array. Recovery is performed with the asynchronous 2339 raid6 recovery routines, and will optionally use an offload 2340 engine if one is available. 2341 2342 If unsure, say N. 2343 2344config TEST_HEXDUMP 2345 tristate "Test functions located in the hexdump module at runtime" 2346 2347config STRING_SELFTEST 2348 tristate "Test string functions at runtime" 2349 2350config TEST_STRING_HELPERS 2351 tristate "Test functions located in the string_helpers module at runtime" 2352 2353config TEST_KSTRTOX 2354 tristate "Test kstrto*() family of functions at runtime" 2355 2356config TEST_PRINTF 2357 tristate "Test printf() family of functions at runtime" 2358 2359config TEST_SCANF 2360 tristate "Test scanf() family of functions at runtime" 2361 2362config TEST_BITMAP 2363 tristate "Test bitmap_*() family of functions at runtime" 2364 help 2365 Enable this option to test the bitmap functions at boot. 2366 2367 If unsure, say N. 2368 2369config TEST_UUID 2370 tristate "Test functions located in the uuid module at runtime" 2371 2372config TEST_XARRAY 2373 tristate "Test the XArray code at runtime" 2374 2375config TEST_MAPLE_TREE 2376 tristate "Test the Maple Tree code at runtime or module load" 2377 help 2378 Enable this option to test the maple tree code functions at boot, or 2379 when the module is loaded. Enable "Debug Maple Trees" will enable 2380 more verbose output on failures. 2381 2382 If unsure, say N. 2383 2384config TEST_RHASHTABLE 2385 tristate "Perform selftest on resizable hash table" 2386 help 2387 Enable this option to test the rhashtable functions at boot. 2388 2389 If unsure, say N. 2390 2391config TEST_IDA 2392 tristate "Perform selftest on IDA functions" 2393 2394config TEST_PARMAN 2395 tristate "Perform selftest on priority array manager" 2396 depends on PARMAN 2397 help 2398 Enable this option to test priority array manager on boot 2399 (or module load). 2400 2401 If unsure, say N. 2402 2403config TEST_IRQ_TIMINGS 2404 bool "IRQ timings selftest" 2405 depends on IRQ_TIMINGS 2406 help 2407 Enable this option to test the irq timings code on boot. 2408 2409 If unsure, say N. 2410 2411config TEST_LKM 2412 tristate "Test module loading with 'hello world' module" 2413 depends on m 2414 help 2415 This builds the "test_module" module that emits "Hello, world" 2416 on printk when loaded. It is designed to be used for basic 2417 evaluation of the module loading subsystem (for example when 2418 validating module verification). It lacks any extra dependencies, 2419 and will not normally be loaded by the system unless explicitly 2420 requested by name. 2421 2422 If unsure, say N. 2423 2424config TEST_BITOPS 2425 tristate "Test module for compilation of bitops operations" 2426 depends on m 2427 help 2428 This builds the "test_bitops" module that is much like the 2429 TEST_LKM module except that it does a basic exercise of the 2430 set/clear_bit macros and get_count_order/long to make sure there are 2431 no compiler warnings from C=1 sparse checker or -Wextra 2432 compilations. It has no dependencies and doesn't run or load unless 2433 explicitly requested by name. for example: modprobe test_bitops. 2434 2435 If unsure, say N. 2436 2437config TEST_VMALLOC 2438 tristate "Test module for stress/performance analysis of vmalloc allocator" 2439 default n 2440 depends on MMU 2441 depends on m 2442 help 2443 This builds the "test_vmalloc" module that should be used for 2444 stress and performance analysis. So, any new change for vmalloc 2445 subsystem can be evaluated from performance and stability point 2446 of view. 2447 2448 If unsure, say N. 2449 2450config TEST_USER_COPY 2451 tristate "Test user/kernel boundary protections" 2452 depends on m 2453 help 2454 This builds the "test_user_copy" module that runs sanity checks 2455 on the copy_to/from_user infrastructure, making sure basic 2456 user/kernel boundary testing is working. If it fails to load, 2457 a regression has been detected in the user/kernel memory boundary 2458 protections. 2459 2460 If unsure, say N. 2461 2462config TEST_BPF 2463 tristate "Test BPF filter functionality" 2464 depends on m && NET 2465 help 2466 This builds the "test_bpf" module that runs various test vectors 2467 against the BPF interpreter or BPF JIT compiler depending on the 2468 current setting. This is in particular useful for BPF JIT compiler 2469 development, but also to run regression tests against changes in 2470 the interpreter code. It also enables test stubs for eBPF maps and 2471 verifier used by user space verifier testsuite. 2472 2473 If unsure, say N. 2474 2475config TEST_BLACKHOLE_DEV 2476 tristate "Test blackhole netdev functionality" 2477 depends on m && NET 2478 help 2479 This builds the "test_blackhole_dev" module that validates the 2480 data path through this blackhole netdev. 2481 2482 If unsure, say N. 2483 2484config FIND_BIT_BENCHMARK 2485 tristate "Test find_bit functions" 2486 help 2487 This builds the "test_find_bit" module that measure find_*_bit() 2488 functions performance. 2489 2490 If unsure, say N. 2491 2492config TEST_FIRMWARE 2493 tristate "Test firmware loading via userspace interface" 2494 depends on FW_LOADER 2495 help 2496 This builds the "test_firmware" module that creates a userspace 2497 interface for testing firmware loading. This can be used to 2498 control the triggering of firmware loading without needing an 2499 actual firmware-using device. The contents can be rechecked by 2500 userspace. 2501 2502 If unsure, say N. 2503 2504config TEST_SYSCTL 2505 tristate "sysctl test driver" 2506 depends on PROC_SYSCTL 2507 help 2508 This builds the "test_sysctl" module. This driver enables to test the 2509 proc sysctl interfaces available to drivers safely without affecting 2510 production knobs which might alter system functionality. 2511 2512 If unsure, say N. 2513 2514config BITFIELD_KUNIT 2515 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2516 depends on KUNIT 2517 default KUNIT_ALL_TESTS 2518 help 2519 Enable this option to test the bitfield functions at boot. 2520 2521 KUnit tests run during boot and output the results to the debug log 2522 in TAP format (http://testanything.org/). Only useful for kernel devs 2523 running the KUnit test harness, and not intended for inclusion into a 2524 production build. 2525 2526 For more information on KUnit and unit tests in general please refer 2527 to the KUnit documentation in Documentation/dev-tools/kunit/. 2528 2529 If unsure, say N. 2530 2531config CHECKSUM_KUNIT 2532 tristate "KUnit test checksum functions at runtime" if !KUNIT_ALL_TESTS 2533 depends on KUNIT 2534 default KUNIT_ALL_TESTS 2535 help 2536 Enable this option to test the checksum functions at boot. 2537 2538 KUnit tests run during boot and output the results to the debug log 2539 in TAP format (http://testanything.org/). Only useful for kernel devs 2540 running the KUnit test harness, and not intended for inclusion into a 2541 production build. 2542 2543 For more information on KUnit and unit tests in general please refer 2544 to the KUnit documentation in Documentation/dev-tools/kunit/. 2545 2546 If unsure, say N. 2547 2548config HASH_KUNIT_TEST 2549 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2550 depends on KUNIT 2551 default KUNIT_ALL_TESTS 2552 help 2553 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2554 integer (<linux/hash.h>) hash functions on boot. 2555 2556 KUnit tests run during boot and output the results to the debug log 2557 in TAP format (https://testanything.org/). Only useful for kernel devs 2558 running the KUnit test harness, and not intended for inclusion into a 2559 production build. 2560 2561 For more information on KUnit and unit tests in general please refer 2562 to the KUnit documentation in Documentation/dev-tools/kunit/. 2563 2564 This is intended to help people writing architecture-specific 2565 optimized versions. If unsure, say N. 2566 2567config RESOURCE_KUNIT_TEST 2568 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2569 depends on KUNIT 2570 default KUNIT_ALL_TESTS 2571 help 2572 This builds the resource API unit test. 2573 Tests the logic of API provided by resource.c and ioport.h. 2574 For more information on KUnit and unit tests in general please refer 2575 to the KUnit documentation in Documentation/dev-tools/kunit/. 2576 2577 If unsure, say N. 2578 2579config SYSCTL_KUNIT_TEST 2580 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2581 depends on KUNIT 2582 default KUNIT_ALL_TESTS 2583 help 2584 This builds the proc sysctl unit test, which runs on boot. 2585 Tests the API contract and implementation correctness of sysctl. 2586 For more information on KUnit and unit tests in general please refer 2587 to the KUnit documentation in Documentation/dev-tools/kunit/. 2588 2589 If unsure, say N. 2590 2591config LIST_KUNIT_TEST 2592 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2593 depends on KUNIT 2594 default KUNIT_ALL_TESTS 2595 help 2596 This builds the linked list KUnit test suite. 2597 It tests that the API and basic functionality of the list_head type 2598 and associated macros. 2599 2600 KUnit tests run during boot and output the results to the debug log 2601 in TAP format (https://testanything.org/). Only useful for kernel devs 2602 running the KUnit test harness, and not intended for inclusion into a 2603 production build. 2604 2605 For more information on KUnit and unit tests in general please refer 2606 to the KUnit documentation in Documentation/dev-tools/kunit/. 2607 2608 If unsure, say N. 2609 2610config HASHTABLE_KUNIT_TEST 2611 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS 2612 depends on KUNIT 2613 default KUNIT_ALL_TESTS 2614 help 2615 This builds the hashtable KUnit test suite. 2616 It tests the basic functionality of the API defined in 2617 include/linux/hashtable.h. For more information on KUnit and 2618 unit tests in general please refer to the KUnit documentation 2619 in Documentation/dev-tools/kunit/. 2620 2621 If unsure, say N. 2622 2623config LINEAR_RANGES_TEST 2624 tristate "KUnit test for linear_ranges" 2625 depends on KUNIT 2626 select LINEAR_RANGES 2627 help 2628 This builds the linear_ranges unit test, which runs on boot. 2629 Tests the linear_ranges logic correctness. 2630 For more information on KUnit and unit tests in general please refer 2631 to the KUnit documentation in Documentation/dev-tools/kunit/. 2632 2633 If unsure, say N. 2634 2635config CMDLINE_KUNIT_TEST 2636 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2637 depends on KUNIT 2638 default KUNIT_ALL_TESTS 2639 help 2640 This builds the cmdline API unit test. 2641 Tests the logic of API provided by cmdline.c. 2642 For more information on KUnit and unit tests in general please refer 2643 to the KUnit documentation in Documentation/dev-tools/kunit/. 2644 2645 If unsure, say N. 2646 2647config BITS_TEST 2648 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2649 depends on KUNIT 2650 default KUNIT_ALL_TESTS 2651 help 2652 This builds the bits unit test. 2653 Tests the logic of macros defined in bits.h. 2654 For more information on KUnit and unit tests in general please refer 2655 to the KUnit documentation in Documentation/dev-tools/kunit/. 2656 2657 If unsure, say N. 2658 2659config SLUB_KUNIT_TEST 2660 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2661 depends on SLUB_DEBUG && KUNIT 2662 default KUNIT_ALL_TESTS 2663 help 2664 This builds SLUB allocator unit test. 2665 Tests SLUB cache debugging functionality. 2666 For more information on KUnit and unit tests in general please refer 2667 to the KUnit documentation in Documentation/dev-tools/kunit/. 2668 2669 If unsure, say N. 2670 2671config RATIONAL_KUNIT_TEST 2672 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2673 depends on KUNIT && RATIONAL 2674 default KUNIT_ALL_TESTS 2675 help 2676 This builds the rational math unit test. 2677 For more information on KUnit and unit tests in general please refer 2678 to the KUnit documentation in Documentation/dev-tools/kunit/. 2679 2680 If unsure, say N. 2681 2682config MEMCPY_KUNIT_TEST 2683 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2684 depends on KUNIT 2685 default KUNIT_ALL_TESTS 2686 help 2687 Builds unit tests for memcpy(), memmove(), and memset() functions. 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 MEMCPY_SLOW_KUNIT_TEST 2694 bool "Include exhaustive memcpy tests" 2695 depends on MEMCPY_KUNIT_TEST 2696 default y 2697 help 2698 Some memcpy tests are quite exhaustive in checking for overlaps 2699 and bit ranges. These can be very slow, so they are split out 2700 as a separate config, in case they need to be disabled. 2701 2702 Note this config option will be replaced by the use of KUnit test 2703 attributes. 2704 2705config IS_SIGNED_TYPE_KUNIT_TEST 2706 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2707 depends on KUNIT 2708 default KUNIT_ALL_TESTS 2709 help 2710 Builds unit tests for the is_signed_type() macro. 2711 2712 For more information on KUnit and unit tests in general please refer 2713 to the KUnit documentation in Documentation/dev-tools/kunit/. 2714 2715 If unsure, say N. 2716 2717config OVERFLOW_KUNIT_TEST 2718 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2719 depends on KUNIT 2720 default KUNIT_ALL_TESTS 2721 help 2722 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2723 related functions. 2724 2725 For more information on KUnit and unit tests in general please refer 2726 to the KUnit documentation in Documentation/dev-tools/kunit/. 2727 2728 If unsure, say N. 2729 2730config STACKINIT_KUNIT_TEST 2731 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2732 depends on KUNIT 2733 default KUNIT_ALL_TESTS 2734 help 2735 Test if the kernel is zero-initializing stack variables and 2736 padding. Coverage is controlled by compiler flags, 2737 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2738 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2739 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2740 2741config FORTIFY_KUNIT_TEST 2742 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2743 depends on KUNIT && FORTIFY_SOURCE 2744 default KUNIT_ALL_TESTS 2745 help 2746 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2747 by the str*() and mem*() family of functions. For testing runtime 2748 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2749 2750config HW_BREAKPOINT_KUNIT_TEST 2751 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2752 depends on HAVE_HW_BREAKPOINT 2753 depends on KUNIT=y 2754 default KUNIT_ALL_TESTS 2755 help 2756 Tests for hw_breakpoint constraints accounting. 2757 2758 If unsure, say N. 2759 2760config STRCAT_KUNIT_TEST 2761 tristate "Test strcat() family of functions at runtime" if !KUNIT_ALL_TESTS 2762 depends on KUNIT 2763 default KUNIT_ALL_TESTS 2764 2765config STRSCPY_KUNIT_TEST 2766 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2767 depends on KUNIT 2768 default KUNIT_ALL_TESTS 2769 2770config SIPHASH_KUNIT_TEST 2771 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2772 depends on KUNIT 2773 default KUNIT_ALL_TESTS 2774 help 2775 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2776 functions on boot (or module load). 2777 2778 This is intended to help people writing architecture-specific 2779 optimized versions. If unsure, say N. 2780 2781config TEST_UDELAY 2782 tristate "udelay test driver" 2783 help 2784 This builds the "udelay_test" module that helps to make sure 2785 that udelay() is working properly. 2786 2787 If unsure, say N. 2788 2789config TEST_STATIC_KEYS 2790 tristate "Test static keys" 2791 depends on m 2792 help 2793 Test the static key interfaces. 2794 2795 If unsure, say N. 2796 2797config TEST_DYNAMIC_DEBUG 2798 tristate "Test DYNAMIC_DEBUG" 2799 depends on DYNAMIC_DEBUG 2800 help 2801 This module registers a tracer callback to count enabled 2802 pr_debugs in a 'do_debugging' function, then alters their 2803 enablements, calls the function, and compares counts. 2804 2805 If unsure, say N. 2806 2807config TEST_KMOD 2808 tristate "kmod stress tester" 2809 depends on m 2810 depends on NETDEVICES && NET_CORE && INET # for TUN 2811 depends on BLOCK 2812 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2813 select TEST_LKM 2814 select XFS_FS 2815 select TUN 2816 select BTRFS_FS 2817 help 2818 Test the kernel's module loading mechanism: kmod. kmod implements 2819 support to load modules using the Linux kernel's usermode helper. 2820 This test provides a series of tests against kmod. 2821 2822 Although technically you can either build test_kmod as a module or 2823 into the kernel we disallow building it into the kernel since 2824 it stress tests request_module() and this will very likely cause 2825 some issues by taking over precious threads available from other 2826 module load requests, ultimately this could be fatal. 2827 2828 To run tests run: 2829 2830 tools/testing/selftests/kmod/kmod.sh --help 2831 2832 If unsure, say N. 2833 2834config TEST_DEBUG_VIRTUAL 2835 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2836 depends on DEBUG_VIRTUAL 2837 help 2838 Test the kernel's ability to detect incorrect calls to 2839 virt_to_phys() done against the non-linear part of the 2840 kernel's virtual address map. 2841 2842 If unsure, say N. 2843 2844config TEST_MEMCAT_P 2845 tristate "Test memcat_p() helper function" 2846 help 2847 Test the memcat_p() helper for correctly merging two 2848 pointer arrays together. 2849 2850 If unsure, say N. 2851 2852config TEST_LIVEPATCH 2853 tristate "Test livepatching" 2854 default n 2855 depends on DYNAMIC_DEBUG 2856 depends on LIVEPATCH 2857 depends on m 2858 help 2859 Test kernel livepatching features for correctness. The tests will 2860 load test modules that will be livepatched in various scenarios. 2861 2862 To run all the livepatching tests: 2863 2864 make -C tools/testing/selftests TARGETS=livepatch run_tests 2865 2866 Alternatively, individual tests may be invoked: 2867 2868 tools/testing/selftests/livepatch/test-callbacks.sh 2869 tools/testing/selftests/livepatch/test-livepatch.sh 2870 tools/testing/selftests/livepatch/test-shadow-vars.sh 2871 2872 If unsure, say N. 2873 2874config TEST_OBJAGG 2875 tristate "Perform selftest on object aggreration manager" 2876 default n 2877 depends on OBJAGG 2878 help 2879 Enable this option to test object aggregation manager on boot 2880 (or module load). 2881 2882config TEST_MEMINIT 2883 tristate "Test heap/page initialization" 2884 help 2885 Test if the kernel is zero-initializing heap and page allocations. 2886 This can be useful to test init_on_alloc and init_on_free features. 2887 2888 If unsure, say N. 2889 2890config TEST_HMM 2891 tristate "Test HMM (Heterogeneous Memory Management)" 2892 depends on TRANSPARENT_HUGEPAGE 2893 depends on DEVICE_PRIVATE 2894 select HMM_MIRROR 2895 select MMU_NOTIFIER 2896 help 2897 This is a pseudo device driver solely for testing HMM. 2898 Say M here if you want to build the HMM test module. 2899 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2900 2901 If unsure, say N. 2902 2903config TEST_FREE_PAGES 2904 tristate "Test freeing pages" 2905 help 2906 Test that a memory leak does not occur due to a race between 2907 freeing a block of pages and a speculative page reference. 2908 Loading this module is safe if your kernel has the bug fixed. 2909 If the bug is not fixed, it will leak gigabytes of memory and 2910 probably OOM your system. 2911 2912config TEST_FPU 2913 tristate "Test floating point operations in kernel space" 2914 depends on X86 && !KCOV_INSTRUMENT_ALL 2915 help 2916 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2917 which will trigger a sequence of floating point operations. This is used 2918 for self-testing floating point control register setting in 2919 kernel_fpu_begin(). 2920 2921 If unsure, say N. 2922 2923config TEST_CLOCKSOURCE_WATCHDOG 2924 tristate "Test clocksource watchdog in kernel space" 2925 depends on CLOCKSOURCE_WATCHDOG 2926 help 2927 Enable this option to create a kernel module that will trigger 2928 a test of the clocksource watchdog. This module may be loaded 2929 via modprobe or insmod in which case it will run upon being 2930 loaded, or it may be built in, in which case it will run 2931 shortly after boot. 2932 2933 If unsure, say N. 2934 2935endif # RUNTIME_TESTING_MENU 2936 2937config ARCH_USE_MEMTEST 2938 bool 2939 help 2940 An architecture should select this when it uses early_memtest() 2941 during boot process. 2942 2943config MEMTEST 2944 bool "Memtest" 2945 depends on ARCH_USE_MEMTEST 2946 help 2947 This option adds a kernel parameter 'memtest', which allows memtest 2948 to be set and executed. 2949 memtest=0, mean disabled; -- default 2950 memtest=1, mean do 1 test pattern; 2951 ... 2952 memtest=17, mean do 17 test patterns. 2953 If you are unsure how to answer this question, answer N. 2954 2955 2956 2957config HYPERV_TESTING 2958 bool "Microsoft Hyper-V driver testing" 2959 default n 2960 depends on HYPERV && DEBUG_FS 2961 help 2962 Select this option to enable Hyper-V vmbus testing. 2963 2964endmenu # "Kernel Testing and Coverage" 2965 2966menu "Rust hacking" 2967 2968config RUST_DEBUG_ASSERTIONS 2969 bool "Debug assertions" 2970 depends on RUST 2971 help 2972 Enables rustc's `-Cdebug-assertions` codegen option. 2973 2974 This flag lets you turn `cfg(debug_assertions)` conditional 2975 compilation on or off. This can be used to enable extra debugging 2976 code in development but not in production. For example, it controls 2977 the behavior of the standard library's `debug_assert!` macro. 2978 2979 Note that this will apply to all Rust code, including `core`. 2980 2981 If unsure, say N. 2982 2983config RUST_OVERFLOW_CHECKS 2984 bool "Overflow checks" 2985 default y 2986 depends on RUST 2987 help 2988 Enables rustc's `-Coverflow-checks` codegen option. 2989 2990 This flag allows you to control the behavior of runtime integer 2991 overflow. When overflow-checks are enabled, a Rust panic will occur 2992 on overflow. 2993 2994 Note that this will apply to all Rust code, including `core`. 2995 2996 If unsure, say Y. 2997 2998config RUST_BUILD_ASSERT_ALLOW 2999 bool "Allow unoptimized build-time assertions" 3000 depends on RUST 3001 help 3002 Controls how `build_error!` and `build_assert!` are handled during the build. 3003 3004 If calls to them exist in the binary, it may indicate a violated invariant 3005 or that the optimizer failed to verify the invariant during compilation. 3006 3007 This should not happen, thus by default the build is aborted. However, 3008 as an escape hatch, you can choose Y here to ignore them during build 3009 and let the check be carried at runtime (with `panic!` being called if 3010 the check fails). 3011 3012 If unsure, say N. 3013 3014config RUST_KERNEL_DOCTESTS 3015 bool "Doctests for the `kernel` crate" if !KUNIT_ALL_TESTS 3016 depends on RUST && KUNIT=y 3017 default KUNIT_ALL_TESTS 3018 help 3019 This builds the documentation tests of the `kernel` crate 3020 as KUnit tests. 3021 3022 For more information on KUnit and unit tests in general, 3023 please refer to the KUnit documentation in Documentation/dev-tools/kunit/. 3024 3025 If unsure, say N. 3026 3027endmenu # "Rust" 3028 3029endmenu # Kernel hacking 3030