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 help 359 Generate debug info into separate .dwo files. This significantly 360 reduces the build directory size for builds with DEBUG_INFO, 361 because it stores the information only once on disk in .dwo 362 files instead of multiple times in object files and executables. 363 In addition the debug information is also compressed. 364 365 Requires recent gcc (4.7+) and recent gdb/binutils. 366 Any tool that packages or reads debug information would need 367 to know about the .dwo files and include them. 368 Incompatible with older versions of ccache. 369 370config DEBUG_INFO_BTF 371 bool "Generate BTF typeinfo" 372 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 373 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 374 depends on BPF_SYSCALL 375 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 376 help 377 Generate deduplicated BTF type information from DWARF debug info. 378 Turning this on expects presence of pahole tool, which will convert 379 DWARF type info into equivalent deduplicated BTF type info. 380 381config PAHOLE_HAS_SPLIT_BTF 382 def_bool PAHOLE_VERSION >= 119 383 384config PAHOLE_HAS_BTF_TAG 385 def_bool PAHOLE_VERSION >= 123 386 depends on CC_IS_CLANG 387 help 388 Decide whether pahole emits btf_tag attributes (btf_type_tag and 389 btf_decl_tag) or not. Currently only clang compiler implements 390 these attributes, so make the config depend on CC_IS_CLANG. 391 392config PAHOLE_HAS_LANG_EXCLUDE 393 def_bool PAHOLE_VERSION >= 124 394 help 395 Support for the --lang_exclude flag which makes pahole exclude 396 compilation units from the supplied language. Used in Kbuild to 397 omit Rust CUs which are not supported in version 1.24 of pahole, 398 otherwise it would emit malformed kernel and module binaries when 399 using DEBUG_INFO_BTF_MODULES. 400 401config DEBUG_INFO_BTF_MODULES 402 def_bool y 403 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 404 help 405 Generate compact split BTF type information for kernel modules. 406 407config MODULE_ALLOW_BTF_MISMATCH 408 bool "Allow loading modules with non-matching BTF type info" 409 depends on DEBUG_INFO_BTF_MODULES 410 help 411 For modules whose split BTF does not match vmlinux, load without 412 BTF rather than refusing to load. The default behavior with 413 module BTF enabled is to reject modules with such mismatches; 414 this option will still load module BTF where possible but ignore 415 it when a mismatch is found. 416 417config GDB_SCRIPTS 418 bool "Provide GDB scripts for kernel debugging" 419 help 420 This creates the required links to GDB helper scripts in the 421 build directory. If you load vmlinux into gdb, the helper 422 scripts will be automatically imported by gdb as well, and 423 additional functions are available to analyze a Linux kernel 424 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 425 for further details. 426 427endif # DEBUG_INFO 428 429config FRAME_WARN 430 int "Warn for stack frames larger than" 431 range 0 8192 432 default 0 if KMSAN 433 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 434 default 2048 if PARISC 435 default 1536 if (!64BIT && XTENSA) 436 default 1280 if KASAN && !64BIT 437 default 1024 if !64BIT 438 default 2048 if 64BIT 439 help 440 Tell the compiler to warn at build time for stack frames larger than this. 441 Setting this too low will cause a lot of warnings. 442 Setting it to 0 disables the warning. 443 444config STRIP_ASM_SYMS 445 bool "Strip assembler-generated symbols during link" 446 default n 447 help 448 Strip internal assembler-generated symbols during a link (symbols 449 that look like '.Lxxx') so they don't pollute the output of 450 get_wchan() and suchlike. 451 452config READABLE_ASM 453 bool "Generate readable assembler code" 454 depends on DEBUG_KERNEL 455 depends on CC_IS_GCC 456 help 457 Disable some compiler optimizations that tend to generate human unreadable 458 assembler output. This may make the kernel slightly slower, but it helps 459 to keep kernel developers who have to stare a lot at assembler listings 460 sane. 461 462config HEADERS_INSTALL 463 bool "Install uapi headers to usr/include" 464 depends on !UML 465 help 466 This option will install uapi headers (headers exported to user-space) 467 into the usr/include directory for use during the kernel build. 468 This is unneeded for building the kernel itself, but needed for some 469 user-space program samples. It is also needed by some features such 470 as uapi header sanity checks. 471 472config DEBUG_SECTION_MISMATCH 473 bool "Enable full Section mismatch analysis" 474 depends on CC_IS_GCC 475 help 476 The section mismatch analysis checks if there are illegal 477 references from one section to another section. 478 During linktime or runtime, some sections are dropped; 479 any use of code/data previously in these sections would 480 most likely result in an oops. 481 In the code, functions and variables are annotated with 482 __init,, etc. (see the full list in include/linux/init.h), 483 which results in the code/data being placed in specific sections. 484 The section mismatch analysis is always performed after a full 485 kernel build, and enabling this option causes the following 486 additional step to occur: 487 - Add the option -fno-inline-functions-called-once to gcc commands. 488 When inlining a function annotated with __init in a non-init 489 function, we would lose the section information and thus 490 the analysis would not catch the illegal reference. 491 This option tells gcc to inline less (but it does result in 492 a larger kernel). 493 494config SECTION_MISMATCH_WARN_ONLY 495 bool "Make section mismatch errors non-fatal" 496 default y 497 help 498 If you say N here, the build process will fail if there are any 499 section mismatch, instead of just throwing warnings. 500 501 If unsure, say Y. 502 503config DEBUG_FORCE_FUNCTION_ALIGN_64B 504 bool "Force all function address 64B aligned" 505 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 506 select FUNCTION_ALIGNMENT_64B 507 help 508 There are cases that a commit from one domain changes the function 509 address alignment of other domains, and cause magic performance 510 bump (regression or improvement). Enable this option will help to 511 verify if the bump is caused by function alignment changes, while 512 it will slightly increase the kernel size and affect icache usage. 513 514 It is mainly for debug and performance tuning use. 515 516# 517# Select this config option from the architecture Kconfig, if it 518# is preferred to always offer frame pointers as a config 519# option on the architecture (regardless of KERNEL_DEBUG): 520# 521config ARCH_WANT_FRAME_POINTERS 522 bool 523 524config FRAME_POINTER 525 bool "Compile the kernel with frame pointers" 526 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 527 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 528 help 529 If you say Y here the resulting kernel image will be slightly 530 larger and slower, but it gives very useful debugging information 531 in case of kernel bugs. (precise oopses/stacktraces/warnings) 532 533config OBJTOOL 534 bool 535 536config STACK_VALIDATION 537 bool "Compile-time stack metadata validation" 538 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 539 select OBJTOOL 540 default n 541 help 542 Validate frame pointer rules at compile-time. This helps ensure that 543 runtime stack traces are more reliable. 544 545 For more information, see 546 tools/objtool/Documentation/objtool.txt. 547 548config NOINSTR_VALIDATION 549 bool 550 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 551 select OBJTOOL 552 default y 553 554config VMLINUX_MAP 555 bool "Generate vmlinux.map file when linking" 556 depends on EXPERT 557 help 558 Selecting this option will pass "-Map=vmlinux.map" to ld 559 when linking vmlinux. That file can be useful for verifying 560 and debugging magic section games, and for seeing which 561 pieces of code get eliminated with 562 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 563 564config DEBUG_FORCE_WEAK_PER_CPU 565 bool "Force weak per-cpu definitions" 566 depends on DEBUG_KERNEL 567 help 568 s390 and alpha require percpu variables in modules to be 569 defined weak to work around addressing range issue which 570 puts the following two restrictions on percpu variable 571 definitions. 572 573 1. percpu symbols must be unique whether static or not 574 2. percpu variables can't be defined inside a function 575 576 To ensure that generic code follows the above rules, this 577 option forces all percpu variables to be defined as weak. 578 579endmenu # "Compiler options" 580 581menu "Generic Kernel Debugging Instruments" 582 583config MAGIC_SYSRQ 584 bool "Magic SysRq key" 585 depends on !UML 586 help 587 If you say Y here, you will have some control over the system even 588 if the system crashes for example during kernel debugging (e.g., you 589 will be able to flush the buffer cache to disk, reboot the system 590 immediately or dump some status information). This is accomplished 591 by pressing various keys while holding SysRq (Alt+PrintScreen). It 592 also works on a serial console (on PC hardware at least), if you 593 send a BREAK and then within 5 seconds a command keypress. The 594 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 595 Don't say Y unless you really know what this hack does. 596 597config MAGIC_SYSRQ_DEFAULT_ENABLE 598 hex "Enable magic SysRq key functions by default" 599 depends on MAGIC_SYSRQ 600 default 0x1 601 help 602 Specifies which SysRq key functions are enabled by default. 603 This may be set to 1 or 0 to enable or disable them all, or 604 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 605 606config MAGIC_SYSRQ_SERIAL 607 bool "Enable magic SysRq key over serial" 608 depends on MAGIC_SYSRQ 609 default y 610 help 611 Many embedded boards have a disconnected TTL level serial which can 612 generate some garbage that can lead to spurious false sysrq detects. 613 This option allows you to decide whether you want to enable the 614 magic SysRq key. 615 616config MAGIC_SYSRQ_SERIAL_SEQUENCE 617 string "Char sequence that enables magic SysRq over serial" 618 depends on MAGIC_SYSRQ_SERIAL 619 default "" 620 help 621 Specifies a sequence of characters that can follow BREAK to enable 622 SysRq on a serial console. 623 624 If unsure, leave an empty string and the option will not be enabled. 625 626config DEBUG_FS 627 bool "Debug Filesystem" 628 help 629 debugfs is a virtual file system that kernel developers use to put 630 debugging files into. Enable this option to be able to read and 631 write to these files. 632 633 For detailed documentation on the debugfs API, see 634 Documentation/filesystems/. 635 636 If unsure, say N. 637 638choice 639 prompt "Debugfs default access" 640 depends on DEBUG_FS 641 default DEBUG_FS_ALLOW_ALL 642 help 643 This selects the default access restrictions for debugfs. 644 It can be overridden with kernel command line option 645 debugfs=[on,no-mount,off]. The restrictions apply for API access 646 and filesystem registration. 647 648config DEBUG_FS_ALLOW_ALL 649 bool "Access normal" 650 help 651 No restrictions apply. Both API and filesystem registration 652 is on. This is the normal default operation. 653 654config DEBUG_FS_DISALLOW_MOUNT 655 bool "Do not register debugfs as filesystem" 656 help 657 The API is open but filesystem is not loaded. Clients can still do 658 their work and read with debug tools that do not need 659 debugfs filesystem. 660 661config DEBUG_FS_ALLOW_NONE 662 bool "No access" 663 help 664 Access is off. Clients get -PERM when trying to create nodes in 665 debugfs tree and debugfs is not registered as a filesystem. 666 Client can then back-off or continue without debugfs access. 667 668endchoice 669 670source "lib/Kconfig.kgdb" 671source "lib/Kconfig.ubsan" 672source "lib/Kconfig.kcsan" 673 674endmenu 675 676menu "Networking Debugging" 677 678source "net/Kconfig.debug" 679 680endmenu # "Networking Debugging" 681 682menu "Memory Debugging" 683 684source "mm/Kconfig.debug" 685 686config DEBUG_OBJECTS 687 bool "Debug object operations" 688 depends on DEBUG_KERNEL 689 help 690 If you say Y here, additional code will be inserted into the 691 kernel to track the life time of various objects and validate 692 the operations on those objects. 693 694config DEBUG_OBJECTS_SELFTEST 695 bool "Debug objects selftest" 696 depends on DEBUG_OBJECTS 697 help 698 This enables the selftest of the object debug code. 699 700config DEBUG_OBJECTS_FREE 701 bool "Debug objects in freed memory" 702 depends on DEBUG_OBJECTS 703 help 704 This enables checks whether a k/v free operation frees an area 705 which contains an object which has not been deactivated 706 properly. This can make kmalloc/kfree-intensive workloads 707 much slower. 708 709config DEBUG_OBJECTS_TIMERS 710 bool "Debug timer objects" 711 depends on DEBUG_OBJECTS 712 help 713 If you say Y here, additional code will be inserted into the 714 timer routines to track the life time of timer objects and 715 validate the timer operations. 716 717config DEBUG_OBJECTS_WORK 718 bool "Debug work objects" 719 depends on DEBUG_OBJECTS 720 help 721 If you say Y here, additional code will be inserted into the 722 work queue routines to track the life time of work objects and 723 validate the work operations. 724 725config DEBUG_OBJECTS_RCU_HEAD 726 bool "Debug RCU callbacks objects" 727 depends on DEBUG_OBJECTS 728 help 729 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 730 731config DEBUG_OBJECTS_PERCPU_COUNTER 732 bool "Debug percpu counter objects" 733 depends on DEBUG_OBJECTS 734 help 735 If you say Y here, additional code will be inserted into the 736 percpu counter routines to track the life time of percpu counter 737 objects and validate the percpu counter operations. 738 739config DEBUG_OBJECTS_ENABLE_DEFAULT 740 int "debug_objects bootup default value (0-1)" 741 range 0 1 742 default "1" 743 depends on DEBUG_OBJECTS 744 help 745 Debug objects boot parameter default value 746 747config SHRINKER_DEBUG 748 bool "Enable shrinker debugging support" 749 depends on DEBUG_FS 750 help 751 Say Y to enable the shrinker debugfs interface which provides 752 visibility into the kernel memory shrinkers subsystem. 753 Disable it to avoid an extra memory footprint. 754 755config DEBUG_STACK_USAGE 756 bool "Stack utilization instrumentation" 757 depends on DEBUG_KERNEL && !IA64 758 help 759 Enables the display of the minimum amount of free stack which each 760 task has ever had available in the sysrq-T and sysrq-P debug output. 761 762 This option will slow down process creation somewhat. 763 764config SCHED_STACK_END_CHECK 765 bool "Detect stack corruption on calls to schedule()" 766 depends on DEBUG_KERNEL 767 default n 768 help 769 This option checks for a stack overrun on calls to schedule(). 770 If the stack end location is found to be over written always panic as 771 the content of the corrupted region can no longer be trusted. 772 This is to ensure no erroneous behaviour occurs which could result in 773 data corruption or a sporadic crash at a later stage once the region 774 is examined. The runtime overhead introduced is minimal. 775 776config ARCH_HAS_DEBUG_VM_PGTABLE 777 bool 778 help 779 An architecture should select this when it can successfully 780 build and run DEBUG_VM_PGTABLE. 781 782config DEBUG_VM_IRQSOFF 783 def_bool DEBUG_VM && !PREEMPT_RT 784 785config DEBUG_VM 786 bool "Debug VM" 787 depends on DEBUG_KERNEL 788 help 789 Enable this to turn on extended checks in the virtual-memory system 790 that may impact performance. 791 792 If unsure, say N. 793 794config DEBUG_VM_MAPLE_TREE 795 bool "Debug VM maple trees" 796 depends on DEBUG_VM 797 select DEBUG_MAPLE_TREE 798 help 799 Enable VM maple tree debugging information and extra validations. 800 801 If unsure, say N. 802 803config DEBUG_VM_RB 804 bool "Debug VM red-black trees" 805 depends on DEBUG_VM 806 help 807 Enable VM red-black tree debugging information and extra validations. 808 809 If unsure, say N. 810 811config DEBUG_VM_PGFLAGS 812 bool "Debug page-flags operations" 813 depends on DEBUG_VM 814 help 815 Enables extra validation on page flags operations. 816 817 If unsure, say N. 818 819config DEBUG_VM_PGTABLE 820 bool "Debug arch page table for semantics compliance" 821 depends on MMU 822 depends on ARCH_HAS_DEBUG_VM_PGTABLE 823 default y if DEBUG_VM 824 help 825 This option provides a debug method which can be used to test 826 architecture page table helper functions on various platforms in 827 verifying if they comply with expected generic MM semantics. This 828 will help architecture code in making sure that any changes or 829 new additions of these helpers still conform to expected 830 semantics of the generic MM. Platforms will have to opt in for 831 this through ARCH_HAS_DEBUG_VM_PGTABLE. 832 833 If unsure, say N. 834 835config ARCH_HAS_DEBUG_VIRTUAL 836 bool 837 838config DEBUG_VIRTUAL 839 bool "Debug VM translations" 840 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 841 help 842 Enable some costly sanity checks in virtual to page code. This can 843 catch mistakes with virt_to_page() and friends. 844 845 If unsure, say N. 846 847config DEBUG_NOMMU_REGIONS 848 bool "Debug the global anon/private NOMMU mapping region tree" 849 depends on DEBUG_KERNEL && !MMU 850 help 851 This option causes the global tree of anonymous and private mapping 852 regions to be regularly checked for invalid topology. 853 854config DEBUG_MEMORY_INIT 855 bool "Debug memory initialisation" if EXPERT 856 default !EXPERT 857 help 858 Enable this for additional checks during memory initialisation. 859 The sanity checks verify aspects of the VM such as the memory model 860 and other information provided by the architecture. Verbose 861 information will be printed at KERN_DEBUG loglevel depending 862 on the mminit_loglevel= command-line option. 863 864 If unsure, say Y 865 866config MEMORY_NOTIFIER_ERROR_INJECT 867 tristate "Memory hotplug notifier error injection module" 868 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 869 help 870 This option provides the ability to inject artificial errors to 871 memory hotplug notifier chain callbacks. It is controlled through 872 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 873 874 If the notifier call chain should be failed with some events 875 notified, write the error code to "actions/<notifier event>/error". 876 877 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 878 879 # cd /sys/kernel/debug/notifier-error-inject/memory 880 # echo -12 > actions/MEM_GOING_OFFLINE/error 881 # echo offline > /sys/devices/system/memory/memoryXXX/state 882 bash: echo: write error: Cannot allocate memory 883 884 To compile this code as a module, choose M here: the module will 885 be called memory-notifier-error-inject. 886 887 If unsure, say N. 888 889config DEBUG_PER_CPU_MAPS 890 bool "Debug access to per_cpu maps" 891 depends on DEBUG_KERNEL 892 depends on SMP 893 help 894 Say Y to verify that the per_cpu map being accessed has 895 been set up. This adds a fair amount of code to kernel memory 896 and decreases performance. 897 898 Say N if unsure. 899 900config DEBUG_KMAP_LOCAL 901 bool "Debug kmap_local temporary mappings" 902 depends on DEBUG_KERNEL && KMAP_LOCAL 903 help 904 This option enables additional error checking for the kmap_local 905 infrastructure. Disable for production use. 906 907config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 908 bool 909 910config DEBUG_KMAP_LOCAL_FORCE_MAP 911 bool "Enforce kmap_local temporary mappings" 912 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 913 select KMAP_LOCAL 914 select DEBUG_KMAP_LOCAL 915 help 916 This option enforces temporary mappings through the kmap_local 917 mechanism for non-highmem pages and on non-highmem systems. 918 Disable this for production systems! 919 920config DEBUG_HIGHMEM 921 bool "Highmem debugging" 922 depends on DEBUG_KERNEL && HIGHMEM 923 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 924 select DEBUG_KMAP_LOCAL 925 help 926 This option enables additional error checking for high memory 927 systems. Disable for production systems. 928 929config HAVE_DEBUG_STACKOVERFLOW 930 bool 931 932config DEBUG_STACKOVERFLOW 933 bool "Check for stack overflows" 934 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 935 help 936 Say Y here if you want to check for overflows of kernel, IRQ 937 and exception stacks (if your architecture uses them). This 938 option will show detailed messages if free stack space drops 939 below a certain limit. 940 941 These kinds of bugs usually occur when call-chains in the 942 kernel get too deep, especially when interrupts are 943 involved. 944 945 Use this in cases where you see apparently random memory 946 corruption, especially if it appears in 'struct thread_info' 947 948 If in doubt, say "N". 949 950source "lib/Kconfig.kasan" 951source "lib/Kconfig.kfence" 952source "lib/Kconfig.kmsan" 953 954endmenu # "Memory Debugging" 955 956config DEBUG_SHIRQ 957 bool "Debug shared IRQ handlers" 958 depends on DEBUG_KERNEL 959 help 960 Enable this to generate a spurious interrupt just before a shared 961 interrupt handler is deregistered (generating one when registering 962 is currently disabled). Drivers need to handle this correctly. Some 963 don't and need to be caught. 964 965menu "Debug Oops, Lockups and Hangs" 966 967config PANIC_ON_OOPS 968 bool "Panic on Oops" 969 help 970 Say Y here to enable the kernel to panic when it oopses. This 971 has the same effect as setting oops=panic on the kernel command 972 line. 973 974 This feature is useful to ensure that the kernel does not do 975 anything erroneous after an oops which could result in data 976 corruption or other issues. 977 978 Say N if unsure. 979 980config PANIC_ON_OOPS_VALUE 981 int 982 range 0 1 983 default 0 if !PANIC_ON_OOPS 984 default 1 if PANIC_ON_OOPS 985 986config PANIC_TIMEOUT 987 int "panic timeout" 988 default 0 989 help 990 Set the timeout value (in seconds) until a reboot occurs when 991 the kernel panics. If n = 0, then we wait forever. A timeout 992 value n > 0 will wait n seconds before rebooting, while a timeout 993 value n < 0 will reboot immediately. 994 995config LOCKUP_DETECTOR 996 bool 997 998config SOFTLOCKUP_DETECTOR 999 bool "Detect Soft Lockups" 1000 depends on DEBUG_KERNEL && !S390 1001 select LOCKUP_DETECTOR 1002 help 1003 Say Y here to enable the kernel to act as a watchdog to detect 1004 soft lockups. 1005 1006 Softlockups are bugs that cause the kernel to loop in kernel 1007 mode for more than 20 seconds, without giving other tasks a 1008 chance to run. The current stack trace is displayed upon 1009 detection and the system will stay locked up. 1010 1011config BOOTPARAM_SOFTLOCKUP_PANIC 1012 bool "Panic (Reboot) On Soft Lockups" 1013 depends on SOFTLOCKUP_DETECTOR 1014 help 1015 Say Y here to enable the kernel to panic on "soft lockups", 1016 which are bugs that cause the kernel to loop in kernel 1017 mode for more than 20 seconds (configurable using the watchdog_thresh 1018 sysctl), without giving other tasks a chance to run. 1019 1020 The panic can be used in combination with panic_timeout, 1021 to cause the system to reboot automatically after a 1022 lockup has been detected. This feature is useful for 1023 high-availability systems that have uptime guarantees and 1024 where a lockup must be resolved ASAP. 1025 1026 Say N if unsure. 1027 1028config HARDLOCKUP_DETECTOR_PERF 1029 bool 1030 select SOFTLOCKUP_DETECTOR 1031 1032# 1033# Enables a timestamp based low pass filter to compensate for perf based 1034# hard lockup detection which runs too fast due to turbo modes. 1035# 1036config HARDLOCKUP_CHECK_TIMESTAMP 1037 bool 1038 1039# 1040# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1041# lockup detector rather than the perf based detector. 1042# 1043config HARDLOCKUP_DETECTOR 1044 bool "Detect Hard Lockups" 1045 depends on DEBUG_KERNEL && !S390 1046 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1047 select LOCKUP_DETECTOR 1048 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1049 help 1050 Say Y here to enable the kernel to act as a watchdog to detect 1051 hard lockups. 1052 1053 Hardlockups are bugs that cause the CPU to loop in kernel mode 1054 for more than 10 seconds, without letting other interrupts have a 1055 chance to run. The current stack trace is displayed upon detection 1056 and the system will stay locked up. 1057 1058config BOOTPARAM_HARDLOCKUP_PANIC 1059 bool "Panic (Reboot) On Hard Lockups" 1060 depends on HARDLOCKUP_DETECTOR 1061 help 1062 Say Y here to enable the kernel to panic on "hard lockups", 1063 which are bugs that cause the kernel to loop in kernel 1064 mode with interrupts disabled for more than 10 seconds (configurable 1065 using the watchdog_thresh sysctl). 1066 1067 Say N if unsure. 1068 1069config DETECT_HUNG_TASK 1070 bool "Detect Hung Tasks" 1071 depends on DEBUG_KERNEL 1072 default SOFTLOCKUP_DETECTOR 1073 help 1074 Say Y here to enable the kernel to detect "hung tasks", 1075 which are bugs that cause the task to be stuck in 1076 uninterruptible "D" state indefinitely. 1077 1078 When a hung task is detected, the kernel will print the 1079 current stack trace (which you should report), but the 1080 task will stay in uninterruptible state. If lockdep is 1081 enabled then all held locks will also be reported. This 1082 feature has negligible overhead. 1083 1084config DEFAULT_HUNG_TASK_TIMEOUT 1085 int "Default timeout for hung task detection (in seconds)" 1086 depends on DETECT_HUNG_TASK 1087 default 120 1088 help 1089 This option controls the default timeout (in seconds) used 1090 to determine when a task has become non-responsive and should 1091 be considered hung. 1092 1093 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1094 sysctl or by writing a value to 1095 /proc/sys/kernel/hung_task_timeout_secs. 1096 1097 A timeout of 0 disables the check. The default is two minutes. 1098 Keeping the default should be fine in most cases. 1099 1100config BOOTPARAM_HUNG_TASK_PANIC 1101 bool "Panic (Reboot) On Hung Tasks" 1102 depends on DETECT_HUNG_TASK 1103 help 1104 Say Y here to enable the kernel to panic on "hung tasks", 1105 which are bugs that cause the kernel to leave a task stuck 1106 in uninterruptible "D" state. 1107 1108 The panic can be used in combination with panic_timeout, 1109 to cause the system to reboot automatically after a 1110 hung task has been detected. This feature is useful for 1111 high-availability systems that have uptime guarantees and 1112 where a hung tasks must be resolved ASAP. 1113 1114 Say N if unsure. 1115 1116config WQ_WATCHDOG 1117 bool "Detect Workqueue Stalls" 1118 depends on DEBUG_KERNEL 1119 help 1120 Say Y here to enable stall detection on workqueues. If a 1121 worker pool doesn't make forward progress on a pending work 1122 item for over a given amount of time, 30s by default, a 1123 warning message is printed along with dump of workqueue 1124 state. This can be configured through kernel parameter 1125 "workqueue.watchdog_thresh" and its sysfs counterpart. 1126 1127config TEST_LOCKUP 1128 tristate "Test module to generate lockups" 1129 depends on m 1130 help 1131 This builds the "test_lockup" module that helps to make sure 1132 that watchdogs and lockup detectors are working properly. 1133 1134 Depending on module parameters it could emulate soft or hard 1135 lockup, "hung task", or locking arbitrary lock for a long time. 1136 Also it could generate series of lockups with cooling-down periods. 1137 1138 If unsure, say N. 1139 1140endmenu # "Debug lockups and hangs" 1141 1142menu "Scheduler Debugging" 1143 1144config SCHED_DEBUG 1145 bool "Collect scheduler debugging info" 1146 depends on DEBUG_KERNEL && PROC_FS 1147 default y 1148 help 1149 If you say Y here, the /sys/kernel/debug/sched file will be provided 1150 that can help debug the scheduler. The runtime overhead of this 1151 option is minimal. 1152 1153config SCHED_INFO 1154 bool 1155 default n 1156 1157config SCHEDSTATS 1158 bool "Collect scheduler statistics" 1159 depends on DEBUG_KERNEL && PROC_FS 1160 select SCHED_INFO 1161 help 1162 If you say Y here, additional code will be inserted into the 1163 scheduler and related routines to collect statistics about 1164 scheduler behavior and provide them in /proc/schedstat. These 1165 stats may be useful for both tuning and debugging the scheduler 1166 If you aren't debugging the scheduler or trying to tune a specific 1167 application, you can say N to avoid the very slight overhead 1168 this adds. 1169 1170endmenu 1171 1172config DEBUG_TIMEKEEPING 1173 bool "Enable extra timekeeping sanity checking" 1174 help 1175 This option will enable additional timekeeping sanity checks 1176 which may be helpful when diagnosing issues where timekeeping 1177 problems are suspected. 1178 1179 This may include checks in the timekeeping hotpaths, so this 1180 option may have a (very small) performance impact to some 1181 workloads. 1182 1183 If unsure, say N. 1184 1185config DEBUG_PREEMPT 1186 bool "Debug preemptible kernel" 1187 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1188 help 1189 If you say Y here then the kernel will use a debug variant of the 1190 commonly used smp_processor_id() function and will print warnings 1191 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1192 will detect preemption count underflows. 1193 1194 This option has potential to introduce high runtime overhead, 1195 depending on workload as it triggers debugging routines for each 1196 this_cpu operation. It should only be used for debugging purposes. 1197 1198menu "Lock Debugging (spinlocks, mutexes, etc...)" 1199 1200config LOCK_DEBUGGING_SUPPORT 1201 bool 1202 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1203 default y 1204 1205config PROVE_LOCKING 1206 bool "Lock debugging: prove locking correctness" 1207 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1208 select LOCKDEP 1209 select DEBUG_SPINLOCK 1210 select DEBUG_MUTEXES if !PREEMPT_RT 1211 select DEBUG_RT_MUTEXES if RT_MUTEXES 1212 select DEBUG_RWSEMS 1213 select DEBUG_WW_MUTEX_SLOWPATH 1214 select DEBUG_LOCK_ALLOC 1215 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1216 select TRACE_IRQFLAGS 1217 default n 1218 help 1219 This feature enables the kernel to prove that all locking 1220 that occurs in the kernel runtime is mathematically 1221 correct: that under no circumstance could an arbitrary (and 1222 not yet triggered) combination of observed locking 1223 sequences (on an arbitrary number of CPUs, running an 1224 arbitrary number of tasks and interrupt contexts) cause a 1225 deadlock. 1226 1227 In short, this feature enables the kernel to report locking 1228 related deadlocks before they actually occur. 1229 1230 The proof does not depend on how hard and complex a 1231 deadlock scenario would be to trigger: how many 1232 participant CPUs, tasks and irq-contexts would be needed 1233 for it to trigger. The proof also does not depend on 1234 timing: if a race and a resulting deadlock is possible 1235 theoretically (no matter how unlikely the race scenario 1236 is), it will be proven so and will immediately be 1237 reported by the kernel (once the event is observed that 1238 makes the deadlock theoretically possible). 1239 1240 If a deadlock is impossible (i.e. the locking rules, as 1241 observed by the kernel, are mathematically correct), the 1242 kernel reports nothing. 1243 1244 NOTE: this feature can also be enabled for rwlocks, mutexes 1245 and rwsems - in which case all dependencies between these 1246 different locking variants are observed and mapped too, and 1247 the proof of observed correctness is also maintained for an 1248 arbitrary combination of these separate locking variants. 1249 1250 For more details, see Documentation/locking/lockdep-design.rst. 1251 1252config PROVE_RAW_LOCK_NESTING 1253 bool "Enable raw_spinlock - spinlock nesting checks" 1254 depends on PROVE_LOCKING 1255 default n 1256 help 1257 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1258 that the lock nesting rules for PREEMPT_RT enabled kernels are 1259 not violated. 1260 1261 NOTE: There are known nesting problems. So if you enable this 1262 option expect lockdep splats until these problems have been fully 1263 addressed which is work in progress. This config switch allows to 1264 identify and analyze these problems. It will be removed and the 1265 check permanently enabled once the main issues have been fixed. 1266 1267 If unsure, select N. 1268 1269config LOCK_STAT 1270 bool "Lock usage statistics" 1271 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1272 select LOCKDEP 1273 select DEBUG_SPINLOCK 1274 select DEBUG_MUTEXES if !PREEMPT_RT 1275 select DEBUG_RT_MUTEXES if RT_MUTEXES 1276 select DEBUG_LOCK_ALLOC 1277 default n 1278 help 1279 This feature enables tracking lock contention points 1280 1281 For more details, see Documentation/locking/lockstat.rst 1282 1283 This also enables lock events required by "perf lock", 1284 subcommand of perf. 1285 If you want to use "perf lock", you also need to turn on 1286 CONFIG_EVENT_TRACING. 1287 1288 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1289 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1290 1291config DEBUG_RT_MUTEXES 1292 bool "RT Mutex debugging, deadlock detection" 1293 depends on DEBUG_KERNEL && RT_MUTEXES 1294 help 1295 This allows rt mutex semantics violations and rt mutex related 1296 deadlocks (lockups) to be detected and reported automatically. 1297 1298config DEBUG_SPINLOCK 1299 bool "Spinlock and rw-lock debugging: basic checks" 1300 depends on DEBUG_KERNEL 1301 select UNINLINE_SPIN_UNLOCK 1302 help 1303 Say Y here and build SMP to catch missing spinlock initialization 1304 and certain other kinds of spinlock errors commonly made. This is 1305 best used in conjunction with the NMI watchdog so that spinlock 1306 deadlocks are also debuggable. 1307 1308config DEBUG_MUTEXES 1309 bool "Mutex debugging: basic checks" 1310 depends on DEBUG_KERNEL && !PREEMPT_RT 1311 help 1312 This feature allows mutex semantics violations to be detected and 1313 reported. 1314 1315config DEBUG_WW_MUTEX_SLOWPATH 1316 bool "Wait/wound mutex debugging: Slowpath testing" 1317 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1318 select DEBUG_LOCK_ALLOC 1319 select DEBUG_SPINLOCK 1320 select DEBUG_MUTEXES if !PREEMPT_RT 1321 select DEBUG_RT_MUTEXES if PREEMPT_RT 1322 help 1323 This feature enables slowpath testing for w/w mutex users by 1324 injecting additional -EDEADLK wound/backoff cases. Together with 1325 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1326 will test all possible w/w mutex interface abuse with the 1327 exception of simply not acquiring all the required locks. 1328 Note that this feature can introduce significant overhead, so 1329 it really should not be enabled in a production or distro kernel, 1330 even a debug kernel. If you are a driver writer, enable it. If 1331 you are a distro, do not. 1332 1333config DEBUG_RWSEMS 1334 bool "RW Semaphore debugging: basic checks" 1335 depends on DEBUG_KERNEL 1336 help 1337 This debugging feature allows mismatched rw semaphore locks 1338 and unlocks to be detected and reported. 1339 1340config DEBUG_LOCK_ALLOC 1341 bool "Lock debugging: detect incorrect freeing of live locks" 1342 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1343 select DEBUG_SPINLOCK 1344 select DEBUG_MUTEXES if !PREEMPT_RT 1345 select DEBUG_RT_MUTEXES if RT_MUTEXES 1346 select LOCKDEP 1347 help 1348 This feature will check whether any held lock (spinlock, rwlock, 1349 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1350 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1351 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1352 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1353 held during task exit. 1354 1355config LOCKDEP 1356 bool 1357 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1358 select STACKTRACE 1359 select KALLSYMS 1360 select KALLSYMS_ALL 1361 1362config LOCKDEP_SMALL 1363 bool 1364 1365config LOCKDEP_BITS 1366 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1367 depends on LOCKDEP && !LOCKDEP_SMALL 1368 range 10 30 1369 default 15 1370 help 1371 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1372 1373config LOCKDEP_CHAINS_BITS 1374 int "Bitsize for MAX_LOCKDEP_CHAINS" 1375 depends on LOCKDEP && !LOCKDEP_SMALL 1376 range 10 30 1377 default 16 1378 help 1379 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1380 1381config LOCKDEP_STACK_TRACE_BITS 1382 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1383 depends on LOCKDEP && !LOCKDEP_SMALL 1384 range 10 30 1385 default 19 1386 help 1387 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1388 1389config LOCKDEP_STACK_TRACE_HASH_BITS 1390 int "Bitsize for STACK_TRACE_HASH_SIZE" 1391 depends on LOCKDEP && !LOCKDEP_SMALL 1392 range 10 30 1393 default 14 1394 help 1395 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1396 1397config LOCKDEP_CIRCULAR_QUEUE_BITS 1398 int "Bitsize for elements in circular_queue struct" 1399 depends on LOCKDEP 1400 range 10 30 1401 default 12 1402 help 1403 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1404 1405config DEBUG_LOCKDEP 1406 bool "Lock dependency engine debugging" 1407 depends on DEBUG_KERNEL && LOCKDEP 1408 select DEBUG_IRQFLAGS 1409 help 1410 If you say Y here, the lock dependency engine will do 1411 additional runtime checks to debug itself, at the price 1412 of more runtime overhead. 1413 1414config DEBUG_ATOMIC_SLEEP 1415 bool "Sleep inside atomic section checking" 1416 select PREEMPT_COUNT 1417 depends on DEBUG_KERNEL 1418 depends on !ARCH_NO_PREEMPT 1419 help 1420 If you say Y here, various routines which may sleep will become very 1421 noisy if they are called inside atomic sections: when a spinlock is 1422 held, inside an rcu read side critical section, inside preempt disabled 1423 sections, inside an interrupt, etc... 1424 1425config DEBUG_LOCKING_API_SELFTESTS 1426 bool "Locking API boot-time self-tests" 1427 depends on DEBUG_KERNEL 1428 help 1429 Say Y here if you want the kernel to run a short self-test during 1430 bootup. The self-test checks whether common types of locking bugs 1431 are detected by debugging mechanisms or not. (if you disable 1432 lock debugging then those bugs won't be detected of course.) 1433 The following locking APIs are covered: spinlocks, rwlocks, 1434 mutexes and rwsems. 1435 1436config LOCK_TORTURE_TEST 1437 tristate "torture tests for locking" 1438 depends on DEBUG_KERNEL 1439 select TORTURE_TEST 1440 help 1441 This option provides a kernel module that runs torture tests 1442 on kernel locking primitives. The kernel module may be built 1443 after the fact on the running kernel to be tested, if desired. 1444 1445 Say Y here if you want kernel locking-primitive torture tests 1446 to be built into the kernel. 1447 Say M if you want these torture tests to build as a module. 1448 Say N if you are unsure. 1449 1450config WW_MUTEX_SELFTEST 1451 tristate "Wait/wound mutex selftests" 1452 help 1453 This option provides a kernel module that runs tests on the 1454 on the struct ww_mutex locking API. 1455 1456 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1457 with this test harness. 1458 1459 Say M if you want these self tests to build as a module. 1460 Say N if you are unsure. 1461 1462config SCF_TORTURE_TEST 1463 tristate "torture tests for smp_call_function*()" 1464 depends on DEBUG_KERNEL 1465 select TORTURE_TEST 1466 help 1467 This option provides a kernel module that runs torture tests 1468 on the smp_call_function() family of primitives. The kernel 1469 module may be built after the fact on the running kernel to 1470 be tested, if desired. 1471 1472config CSD_LOCK_WAIT_DEBUG 1473 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1474 depends on DEBUG_KERNEL 1475 depends on 64BIT 1476 default n 1477 help 1478 This option enables debug prints when CPUs are slow to respond 1479 to the smp_call_function*() IPI wrappers. These debug prints 1480 include the IPI handler function currently executing (if any) 1481 and relevant stack traces. 1482 1483endmenu # lock debugging 1484 1485config TRACE_IRQFLAGS 1486 depends on TRACE_IRQFLAGS_SUPPORT 1487 bool 1488 help 1489 Enables hooks to interrupt enabling and disabling for 1490 either tracing or lock debugging. 1491 1492config TRACE_IRQFLAGS_NMI 1493 def_bool y 1494 depends on TRACE_IRQFLAGS 1495 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1496 1497config NMI_CHECK_CPU 1498 bool "Debugging for CPUs failing to respond to backtrace requests" 1499 depends on DEBUG_KERNEL 1500 depends on X86 1501 default n 1502 help 1503 Enables debug prints when a CPU fails to respond to a given 1504 backtrace NMI. These prints provide some reasons why a CPU 1505 might legitimately be failing to respond, for example, if it 1506 is offline of if ignore_nmis is set. 1507 1508config DEBUG_IRQFLAGS 1509 bool "Debug IRQ flag manipulation" 1510 help 1511 Enables checks for potentially unsafe enabling or disabling of 1512 interrupts, such as calling raw_local_irq_restore() when interrupts 1513 are enabled. 1514 1515config STACKTRACE 1516 bool "Stack backtrace support" 1517 depends on STACKTRACE_SUPPORT 1518 help 1519 This option causes the kernel to create a /proc/pid/stack for 1520 every process, showing its current stack trace. 1521 It is also used by various kernel debugging features that require 1522 stack trace generation. 1523 1524config WARN_ALL_UNSEEDED_RANDOM 1525 bool "Warn for all uses of unseeded randomness" 1526 default n 1527 help 1528 Some parts of the kernel contain bugs relating to their use of 1529 cryptographically secure random numbers before it's actually possible 1530 to generate those numbers securely. This setting ensures that these 1531 flaws don't go unnoticed, by enabling a message, should this ever 1532 occur. This will allow people with obscure setups to know when things 1533 are going wrong, so that they might contact developers about fixing 1534 it. 1535 1536 Unfortunately, on some models of some architectures getting 1537 a fully seeded CRNG is extremely difficult, and so this can 1538 result in dmesg getting spammed for a surprisingly long 1539 time. This is really bad from a security perspective, and 1540 so architecture maintainers really need to do what they can 1541 to get the CRNG seeded sooner after the system is booted. 1542 However, since users cannot do anything actionable to 1543 address this, by default this option is disabled. 1544 1545 Say Y here if you want to receive warnings for all uses of 1546 unseeded randomness. This will be of use primarily for 1547 those developers interested in improving the security of 1548 Linux kernels running on their architecture (or 1549 subarchitecture). 1550 1551config DEBUG_KOBJECT 1552 bool "kobject debugging" 1553 depends on DEBUG_KERNEL 1554 help 1555 If you say Y here, some extra kobject debugging messages will be sent 1556 to the syslog. 1557 1558config DEBUG_KOBJECT_RELEASE 1559 bool "kobject release debugging" 1560 depends on DEBUG_OBJECTS_TIMERS 1561 help 1562 kobjects are reference counted objects. This means that their 1563 last reference count put is not predictable, and the kobject can 1564 live on past the point at which a driver decides to drop its 1565 initial reference to the kobject gained on allocation. An 1566 example of this would be a struct device which has just been 1567 unregistered. 1568 1569 However, some buggy drivers assume that after such an operation, 1570 the memory backing the kobject can be immediately freed. This 1571 goes completely against the principles of a refcounted object. 1572 1573 If you say Y here, the kernel will delay the release of kobjects 1574 on the last reference count to improve the visibility of this 1575 kind of kobject release bug. 1576 1577config HAVE_DEBUG_BUGVERBOSE 1578 bool 1579 1580menu "Debug kernel data structures" 1581 1582config DEBUG_LIST 1583 bool "Debug linked list manipulation" 1584 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1585 help 1586 Enable this to turn on extended checks in the linked-list 1587 walking routines. 1588 1589 If unsure, say N. 1590 1591config DEBUG_PLIST 1592 bool "Debug priority linked list manipulation" 1593 depends on DEBUG_KERNEL 1594 help 1595 Enable this to turn on extended checks in the priority-ordered 1596 linked-list (plist) walking routines. This checks the entire 1597 list multiple times during each manipulation. 1598 1599 If unsure, say N. 1600 1601config DEBUG_SG 1602 bool "Debug SG table operations" 1603 depends on DEBUG_KERNEL 1604 help 1605 Enable this to turn on checks on scatter-gather tables. This can 1606 help find problems with drivers that do not properly initialize 1607 their sg tables. 1608 1609 If unsure, say N. 1610 1611config DEBUG_NOTIFIERS 1612 bool "Debug notifier call chains" 1613 depends on DEBUG_KERNEL 1614 help 1615 Enable this to turn on sanity checking for notifier call chains. 1616 This is most useful for kernel developers to make sure that 1617 modules properly unregister themselves from notifier chains. 1618 This is a relatively cheap check but if you care about maximum 1619 performance, say N. 1620 1621config BUG_ON_DATA_CORRUPTION 1622 bool "Trigger a BUG when data corruption is detected" 1623 select DEBUG_LIST 1624 help 1625 Select this option if the kernel should BUG when it encounters 1626 data corruption in kernel memory structures when they get checked 1627 for validity. 1628 1629 If unsure, say N. 1630 1631config DEBUG_MAPLE_TREE 1632 bool "Debug maple trees" 1633 depends on DEBUG_KERNEL 1634 help 1635 Enable maple tree debugging information and extra validations. 1636 1637 If unsure, say N. 1638 1639endmenu 1640 1641config DEBUG_CREDENTIALS 1642 bool "Debug credential management" 1643 depends on DEBUG_KERNEL 1644 help 1645 Enable this to turn on some debug checking for credential 1646 management. The additional code keeps track of the number of 1647 pointers from task_structs to any given cred struct, and checks to 1648 see that this number never exceeds the usage count of the cred 1649 struct. 1650 1651 Furthermore, if SELinux is enabled, this also checks that the 1652 security pointer in the cred struct is never seen to be invalid. 1653 1654 If unsure, say N. 1655 1656source "kernel/rcu/Kconfig.debug" 1657 1658config DEBUG_WQ_FORCE_RR_CPU 1659 bool "Force round-robin CPU selection for unbound work items" 1660 depends on DEBUG_KERNEL 1661 default n 1662 help 1663 Workqueue used to implicitly guarantee that work items queued 1664 without explicit CPU specified are put on the local CPU. This 1665 guarantee is no longer true and while local CPU is still 1666 preferred work items may be put on foreign CPUs. Kernel 1667 parameter "workqueue.debug_force_rr_cpu" is added to force 1668 round-robin CPU selection to flush out usages which depend on the 1669 now broken guarantee. This config option enables the debug 1670 feature by default. When enabled, memory and cache locality will 1671 be impacted. 1672 1673config CPU_HOTPLUG_STATE_CONTROL 1674 bool "Enable CPU hotplug state control" 1675 depends on DEBUG_KERNEL 1676 depends on HOTPLUG_CPU 1677 default n 1678 help 1679 Allows to write steps between "offline" and "online" to the CPUs 1680 sysfs target file so states can be stepped granular. This is a debug 1681 option for now as the hotplug machinery cannot be stopped and 1682 restarted at arbitrary points yet. 1683 1684 Say N if your are unsure. 1685 1686config LATENCYTOP 1687 bool "Latency measuring infrastructure" 1688 depends on DEBUG_KERNEL 1689 depends on STACKTRACE_SUPPORT 1690 depends on PROC_FS 1691 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1692 select KALLSYMS 1693 select KALLSYMS_ALL 1694 select STACKTRACE 1695 select SCHEDSTATS 1696 help 1697 Enable this option if you want to use the LatencyTOP tool 1698 to find out which userspace is blocking on what kernel operations. 1699 1700config DEBUG_CGROUP_REF 1701 bool "Disable inlining of cgroup css reference count functions" 1702 depends on DEBUG_KERNEL 1703 depends on CGROUPS 1704 depends on KPROBES 1705 default n 1706 help 1707 Force cgroup css reference count functions to not be inlined so 1708 that they can be kprobed for debugging. 1709 1710source "kernel/trace/Kconfig" 1711 1712config PROVIDE_OHCI1394_DMA_INIT 1713 bool "Remote debugging over FireWire early on boot" 1714 depends on PCI && X86 1715 help 1716 If you want to debug problems which hang or crash the kernel early 1717 on boot and the crashing machine has a FireWire port, you can use 1718 this feature to remotely access the memory of the crashed machine 1719 over FireWire. This employs remote DMA as part of the OHCI1394 1720 specification which is now the standard for FireWire controllers. 1721 1722 With remote DMA, you can monitor the printk buffer remotely using 1723 firescope and access all memory below 4GB using fireproxy from gdb. 1724 Even controlling a kernel debugger is possible using remote DMA. 1725 1726 Usage: 1727 1728 If ohci1394_dma=early is used as boot parameter, it will initialize 1729 all OHCI1394 controllers which are found in the PCI config space. 1730 1731 As all changes to the FireWire bus such as enabling and disabling 1732 devices cause a bus reset and thereby disable remote DMA for all 1733 devices, be sure to have the cable plugged and FireWire enabled on 1734 the debugging host before booting the debug target for debugging. 1735 1736 This code (~1k) is freed after boot. By then, the firewire stack 1737 in charge of the OHCI-1394 controllers should be used instead. 1738 1739 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1740 1741source "samples/Kconfig" 1742 1743config ARCH_HAS_DEVMEM_IS_ALLOWED 1744 bool 1745 1746config STRICT_DEVMEM 1747 bool "Filter access to /dev/mem" 1748 depends on MMU && DEVMEM 1749 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1750 default y if PPC || X86 || ARM64 1751 help 1752 If this option is disabled, you allow userspace (root) access to all 1753 of memory, including kernel and userspace memory. Accidental 1754 access to this is obviously disastrous, but specific access can 1755 be used by people debugging the kernel. Note that with PAT support 1756 enabled, even in this case there are restrictions on /dev/mem 1757 use due to the cache aliasing requirements. 1758 1759 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1760 file only allows userspace access to PCI space and the BIOS code and 1761 data regions. This is sufficient for dosemu and X and all common 1762 users of /dev/mem. 1763 1764 If in doubt, say Y. 1765 1766config IO_STRICT_DEVMEM 1767 bool "Filter I/O access to /dev/mem" 1768 depends on STRICT_DEVMEM 1769 help 1770 If this option is disabled, you allow userspace (root) access to all 1771 io-memory regardless of whether a driver is actively using that 1772 range. Accidental access to this is obviously disastrous, but 1773 specific access can be used by people debugging kernel drivers. 1774 1775 If this option is switched on, the /dev/mem file only allows 1776 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1777 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1778 if the driver using a given range cannot be disabled. 1779 1780 If in doubt, say Y. 1781 1782menu "$(SRCARCH) Debugging" 1783 1784source "arch/$(SRCARCH)/Kconfig.debug" 1785 1786endmenu 1787 1788menu "Kernel Testing and Coverage" 1789 1790source "lib/kunit/Kconfig" 1791 1792config NOTIFIER_ERROR_INJECTION 1793 tristate "Notifier error injection" 1794 depends on DEBUG_KERNEL 1795 select DEBUG_FS 1796 help 1797 This option provides the ability to inject artificial errors to 1798 specified notifier chain callbacks. It is useful to test the error 1799 handling of notifier call chain failures. 1800 1801 Say N if unsure. 1802 1803config PM_NOTIFIER_ERROR_INJECT 1804 tristate "PM notifier error injection module" 1805 depends on PM && NOTIFIER_ERROR_INJECTION 1806 default m if PM_DEBUG 1807 help 1808 This option provides the ability to inject artificial errors to 1809 PM notifier chain callbacks. It is controlled through debugfs 1810 interface /sys/kernel/debug/notifier-error-inject/pm 1811 1812 If the notifier call chain should be failed with some events 1813 notified, write the error code to "actions/<notifier event>/error". 1814 1815 Example: Inject PM suspend error (-12 = -ENOMEM) 1816 1817 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1818 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1819 # echo mem > /sys/power/state 1820 bash: echo: write error: Cannot allocate memory 1821 1822 To compile this code as a module, choose M here: the module will 1823 be called pm-notifier-error-inject. 1824 1825 If unsure, say N. 1826 1827config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1828 tristate "OF reconfig notifier error injection module" 1829 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1830 help 1831 This option provides the ability to inject artificial errors to 1832 OF reconfig notifier chain callbacks. It is controlled 1833 through debugfs interface under 1834 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1835 1836 If the notifier call chain should be failed with some events 1837 notified, write the error code to "actions/<notifier event>/error". 1838 1839 To compile this code as a module, choose M here: the module will 1840 be called of-reconfig-notifier-error-inject. 1841 1842 If unsure, say N. 1843 1844config NETDEV_NOTIFIER_ERROR_INJECT 1845 tristate "Netdev notifier error injection module" 1846 depends on NET && NOTIFIER_ERROR_INJECTION 1847 help 1848 This option provides the ability to inject artificial errors to 1849 netdevice notifier chain callbacks. It is controlled through debugfs 1850 interface /sys/kernel/debug/notifier-error-inject/netdev 1851 1852 If the notifier call chain should be failed with some events 1853 notified, write the error code to "actions/<notifier event>/error". 1854 1855 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1856 1857 # cd /sys/kernel/debug/notifier-error-inject/netdev 1858 # echo -22 > actions/NETDEV_CHANGEMTU/error 1859 # ip link set eth0 mtu 1024 1860 RTNETLINK answers: Invalid argument 1861 1862 To compile this code as a module, choose M here: the module will 1863 be called netdev-notifier-error-inject. 1864 1865 If unsure, say N. 1866 1867config FUNCTION_ERROR_INJECTION 1868 bool "Fault-injections of functions" 1869 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1870 help 1871 Add fault injections into various functions that are annotated with 1872 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1873 value of these functions. This is useful to test error paths of code. 1874 1875 If unsure, say N 1876 1877config FAULT_INJECTION 1878 bool "Fault-injection framework" 1879 depends on DEBUG_KERNEL 1880 help 1881 Provide fault-injection framework. 1882 For more details, see Documentation/fault-injection/. 1883 1884config FAILSLAB 1885 bool "Fault-injection capability for kmalloc" 1886 depends on FAULT_INJECTION 1887 depends on SLAB || SLUB 1888 help 1889 Provide fault-injection capability for kmalloc. 1890 1891config FAIL_PAGE_ALLOC 1892 bool "Fault-injection capability for alloc_pages()" 1893 depends on FAULT_INJECTION 1894 help 1895 Provide fault-injection capability for alloc_pages(). 1896 1897config FAULT_INJECTION_USERCOPY 1898 bool "Fault injection capability for usercopy functions" 1899 depends on FAULT_INJECTION 1900 help 1901 Provides fault-injection capability to inject failures 1902 in usercopy functions (copy_from_user(), get_user(), ...). 1903 1904config FAIL_MAKE_REQUEST 1905 bool "Fault-injection capability for disk IO" 1906 depends on FAULT_INJECTION && BLOCK 1907 help 1908 Provide fault-injection capability for disk IO. 1909 1910config FAIL_IO_TIMEOUT 1911 bool "Fault-injection capability for faking disk interrupts" 1912 depends on FAULT_INJECTION && BLOCK 1913 help 1914 Provide fault-injection capability on end IO handling. This 1915 will make the block layer "forget" an interrupt as configured, 1916 thus exercising the error handling. 1917 1918 Only works with drivers that use the generic timeout handling, 1919 for others it won't do anything. 1920 1921config FAIL_FUTEX 1922 bool "Fault-injection capability for futexes" 1923 select DEBUG_FS 1924 depends on FAULT_INJECTION && FUTEX 1925 help 1926 Provide fault-injection capability for futexes. 1927 1928config FAULT_INJECTION_DEBUG_FS 1929 bool "Debugfs entries for fault-injection capabilities" 1930 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1931 help 1932 Enable configuration of fault-injection capabilities via debugfs. 1933 1934config FAIL_FUNCTION 1935 bool "Fault-injection capability for functions" 1936 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1937 help 1938 Provide function-based fault-injection capability. 1939 This will allow you to override a specific function with a return 1940 with given return value. As a result, function caller will see 1941 an error value and have to handle it. This is useful to test the 1942 error handling in various subsystems. 1943 1944config FAIL_MMC_REQUEST 1945 bool "Fault-injection capability for MMC IO" 1946 depends on FAULT_INJECTION_DEBUG_FS && MMC 1947 help 1948 Provide fault-injection capability for MMC IO. 1949 This will make the mmc core return data errors. This is 1950 useful to test the error handling in the mmc block device 1951 and to test how the mmc host driver handles retries from 1952 the block device. 1953 1954config FAIL_SUNRPC 1955 bool "Fault-injection capability for SunRPC" 1956 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1957 help 1958 Provide fault-injection capability for SunRPC and 1959 its consumers. 1960 1961config FAULT_INJECTION_STACKTRACE_FILTER 1962 bool "stacktrace filter for fault-injection capabilities" 1963 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1964 select STACKTRACE 1965 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1966 help 1967 Provide stacktrace filter for fault-injection capabilities 1968 1969config ARCH_HAS_KCOV 1970 bool 1971 help 1972 An architecture should select this when it can successfully 1973 build and run with CONFIG_KCOV. This typically requires 1974 disabling instrumentation for some early boot code. 1975 1976config CC_HAS_SANCOV_TRACE_PC 1977 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1978 1979 1980config KCOV 1981 bool "Code coverage for fuzzing" 1982 depends on ARCH_HAS_KCOV 1983 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1984 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 1985 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 1986 select DEBUG_FS 1987 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1988 select OBJTOOL if HAVE_NOINSTR_HACK 1989 help 1990 KCOV exposes kernel code coverage information in a form suitable 1991 for coverage-guided fuzzing (randomized testing). 1992 1993 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1994 different machines and across reboots. If you need stable PC values, 1995 disable RANDOMIZE_BASE. 1996 1997 For more details, see Documentation/dev-tools/kcov.rst. 1998 1999config KCOV_ENABLE_COMPARISONS 2000 bool "Enable comparison operands collection by KCOV" 2001 depends on KCOV 2002 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2003 help 2004 KCOV also exposes operands of every comparison in the instrumented 2005 code along with operand sizes and PCs of the comparison instructions. 2006 These operands can be used by fuzzing engines to improve the quality 2007 of fuzzing coverage. 2008 2009config KCOV_INSTRUMENT_ALL 2010 bool "Instrument all code by default" 2011 depends on KCOV 2012 default y 2013 help 2014 If you are doing generic system call fuzzing (like e.g. syzkaller), 2015 then you will want to instrument the whole kernel and you should 2016 say y here. If you are doing more targeted fuzzing (like e.g. 2017 filesystem fuzzing with AFL) then you will want to enable coverage 2018 for more specific subsets of files, and should say n here. 2019 2020config KCOV_IRQ_AREA_SIZE 2021 hex "Size of interrupt coverage collection area in words" 2022 depends on KCOV 2023 default 0x40000 2024 help 2025 KCOV uses preallocated per-cpu areas to collect coverage from 2026 soft interrupts. This specifies the size of those areas in the 2027 number of unsigned long words. 2028 2029menuconfig RUNTIME_TESTING_MENU 2030 bool "Runtime Testing" 2031 def_bool y 2032 2033if RUNTIME_TESTING_MENU 2034 2035config TEST_DHRY 2036 tristate "Dhrystone benchmark test" 2037 help 2038 Enable this to include the Dhrystone 2.1 benchmark. This test 2039 calculates the number of Dhrystones per second, and the number of 2040 DMIPS (Dhrystone MIPS) obtained when the Dhrystone score is divided 2041 by 1757 (the number of Dhrystones per second obtained on the VAX 2042 11/780, nominally a 1 MIPS machine). 2043 2044 To run the benchmark, it needs to be enabled explicitly, either from 2045 the kernel command line (when built-in), or from userspace (when 2046 built-in or modular. 2047 2048 Run once during kernel boot: 2049 2050 test_dhry.run 2051 2052 Set number of iterations from kernel command line: 2053 2054 test_dhry.iterations=<n> 2055 2056 Set number of iterations from userspace: 2057 2058 echo <n> > /sys/module/test_dhry/parameters/iterations 2059 2060 Trigger manual run from userspace: 2061 2062 echo y > /sys/module/test_dhry/parameters/run 2063 2064 If the number of iterations is <= 0, the test will devise a suitable 2065 number of iterations (test runs for at least 2s) automatically. 2066 This process takes ca. 4s. 2067 2068 If unsure, say N. 2069 2070config LKDTM 2071 tristate "Linux Kernel Dump Test Tool Module" 2072 depends on DEBUG_FS 2073 help 2074 This module enables testing of the different dumping mechanisms by 2075 inducing system failures at predefined crash points. 2076 If you don't need it: say N 2077 Choose M here to compile this code as a module. The module will be 2078 called lkdtm. 2079 2080 Documentation on how to use the module can be found in 2081 Documentation/fault-injection/provoke-crashes.rst 2082 2083config CPUMASK_KUNIT_TEST 2084 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2085 depends on KUNIT 2086 default KUNIT_ALL_TESTS 2087 help 2088 Enable to turn on cpumask tests, running at boot or module load time. 2089 2090 For more information on KUnit and unit tests in general, please refer 2091 to the KUnit documentation in Documentation/dev-tools/kunit/. 2092 2093 If unsure, say N. 2094 2095config TEST_LIST_SORT 2096 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2097 depends on KUNIT 2098 default KUNIT_ALL_TESTS 2099 help 2100 Enable this to turn on 'list_sort()' function test. This test is 2101 executed only once during system boot (so affects only boot time), 2102 or at module load time. 2103 2104 If unsure, say N. 2105 2106config TEST_MIN_HEAP 2107 tristate "Min heap test" 2108 depends on DEBUG_KERNEL || m 2109 help 2110 Enable this to turn on min heap function tests. This test is 2111 executed only once during system boot (so affects only boot time), 2112 or at module load time. 2113 2114 If unsure, say N. 2115 2116config TEST_SORT 2117 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2118 depends on KUNIT 2119 default KUNIT_ALL_TESTS 2120 help 2121 This option enables the self-test function of 'sort()' at boot, 2122 or at module load time. 2123 2124 If unsure, say N. 2125 2126config TEST_DIV64 2127 tristate "64bit/32bit division and modulo test" 2128 depends on DEBUG_KERNEL || m 2129 help 2130 Enable this to turn on 'do_div()' function test. This test is 2131 executed only once during system boot (so affects only boot time), 2132 or at module load time. 2133 2134 If unsure, say N. 2135 2136config KPROBES_SANITY_TEST 2137 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2138 depends on DEBUG_KERNEL 2139 depends on KPROBES 2140 depends on KUNIT 2141 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2142 default KUNIT_ALL_TESTS 2143 help 2144 This option provides for testing basic kprobes functionality on 2145 boot. Samples of kprobe and kretprobe are inserted and 2146 verified for functionality. 2147 2148 Say N if you are unsure. 2149 2150config FPROBE_SANITY_TEST 2151 bool "Self test for fprobe" 2152 depends on DEBUG_KERNEL 2153 depends on FPROBE 2154 depends on KUNIT=y 2155 help 2156 This option will enable testing the fprobe when the system boot. 2157 A series of tests are made to verify that the fprobe is functioning 2158 properly. 2159 2160 Say N if you are unsure. 2161 2162config BACKTRACE_SELF_TEST 2163 tristate "Self test for the backtrace code" 2164 depends on DEBUG_KERNEL 2165 help 2166 This option provides a kernel module that can be used to test 2167 the kernel stack backtrace code. This option is not useful 2168 for distributions or general kernels, but only for kernel 2169 developers working on architecture code. 2170 2171 Note that if you want to also test saved backtraces, you will 2172 have to enable STACKTRACE as well. 2173 2174 Say N if you are unsure. 2175 2176config TEST_REF_TRACKER 2177 tristate "Self test for reference tracker" 2178 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2179 select REF_TRACKER 2180 help 2181 This option provides a kernel module performing tests 2182 using reference tracker infrastructure. 2183 2184 Say N if you are unsure. 2185 2186config RBTREE_TEST 2187 tristate "Red-Black tree test" 2188 depends on DEBUG_KERNEL 2189 help 2190 A benchmark measuring the performance of the rbtree library. 2191 Also includes rbtree invariant checks. 2192 2193config REED_SOLOMON_TEST 2194 tristate "Reed-Solomon library test" 2195 depends on DEBUG_KERNEL || m 2196 select REED_SOLOMON 2197 select REED_SOLOMON_ENC16 2198 select REED_SOLOMON_DEC16 2199 help 2200 This option enables the self-test function of rslib at boot, 2201 or at module load time. 2202 2203 If unsure, say N. 2204 2205config INTERVAL_TREE_TEST 2206 tristate "Interval tree test" 2207 depends on DEBUG_KERNEL 2208 select INTERVAL_TREE 2209 help 2210 A benchmark measuring the performance of the interval tree library 2211 2212config PERCPU_TEST 2213 tristate "Per cpu operations test" 2214 depends on m && DEBUG_KERNEL 2215 help 2216 Enable this option to build test module which validates per-cpu 2217 operations. 2218 2219 If unsure, say N. 2220 2221config ATOMIC64_SELFTEST 2222 tristate "Perform an atomic64_t self-test" 2223 help 2224 Enable this option to test the atomic64_t functions at boot or 2225 at module load time. 2226 2227 If unsure, say N. 2228 2229config ASYNC_RAID6_TEST 2230 tristate "Self test for hardware accelerated raid6 recovery" 2231 depends on ASYNC_RAID6_RECOV 2232 select ASYNC_MEMCPY 2233 help 2234 This is a one-shot self test that permutes through the 2235 recovery of all the possible two disk failure scenarios for a 2236 N-disk array. Recovery is performed with the asynchronous 2237 raid6 recovery routines, and will optionally use an offload 2238 engine if one is available. 2239 2240 If unsure, say N. 2241 2242config TEST_HEXDUMP 2243 tristate "Test functions located in the hexdump module at runtime" 2244 2245config STRING_SELFTEST 2246 tristate "Test string functions at runtime" 2247 2248config TEST_STRING_HELPERS 2249 tristate "Test functions located in the string_helpers module at runtime" 2250 2251config TEST_KSTRTOX 2252 tristate "Test kstrto*() family of functions at runtime" 2253 2254config TEST_PRINTF 2255 tristate "Test printf() family of functions at runtime" 2256 2257config TEST_SCANF 2258 tristate "Test scanf() family of functions at runtime" 2259 2260config TEST_BITMAP 2261 tristate "Test bitmap_*() family of functions at runtime" 2262 help 2263 Enable this option to test the bitmap functions at boot. 2264 2265 If unsure, say N. 2266 2267config TEST_UUID 2268 tristate "Test functions located in the uuid module at runtime" 2269 2270config TEST_XARRAY 2271 tristate "Test the XArray code at runtime" 2272 2273config TEST_MAPLE_TREE 2274 depends on DEBUG_KERNEL 2275 select DEBUG_MAPLE_TREE 2276 tristate "Test the Maple Tree code at runtime" 2277 2278config TEST_RHASHTABLE 2279 tristate "Perform selftest on resizable hash table" 2280 help 2281 Enable this option to test the rhashtable functions at boot. 2282 2283 If unsure, say N. 2284 2285config TEST_IDA 2286 tristate "Perform selftest on IDA functions" 2287 2288config TEST_PARMAN 2289 tristate "Perform selftest on priority array manager" 2290 depends on PARMAN 2291 help 2292 Enable this option to test priority array manager on boot 2293 (or module load). 2294 2295 If unsure, say N. 2296 2297config TEST_IRQ_TIMINGS 2298 bool "IRQ timings selftest" 2299 depends on IRQ_TIMINGS 2300 help 2301 Enable this option to test the irq timings code on boot. 2302 2303 If unsure, say N. 2304 2305config TEST_LKM 2306 tristate "Test module loading with 'hello world' module" 2307 depends on m 2308 help 2309 This builds the "test_module" module that emits "Hello, world" 2310 on printk when loaded. It is designed to be used for basic 2311 evaluation of the module loading subsystem (for example when 2312 validating module verification). It lacks any extra dependencies, 2313 and will not normally be loaded by the system unless explicitly 2314 requested by name. 2315 2316 If unsure, say N. 2317 2318config TEST_BITOPS 2319 tristate "Test module for compilation of bitops operations" 2320 depends on m 2321 help 2322 This builds the "test_bitops" module that is much like the 2323 TEST_LKM module except that it does a basic exercise of the 2324 set/clear_bit macros and get_count_order/long to make sure there are 2325 no compiler warnings from C=1 sparse checker or -Wextra 2326 compilations. It has no dependencies and doesn't run or load unless 2327 explicitly requested by name. for example: modprobe test_bitops. 2328 2329 If unsure, say N. 2330 2331config TEST_VMALLOC 2332 tristate "Test module for stress/performance analysis of vmalloc allocator" 2333 default n 2334 depends on MMU 2335 depends on m 2336 help 2337 This builds the "test_vmalloc" module that should be used for 2338 stress and performance analysis. So, any new change for vmalloc 2339 subsystem can be evaluated from performance and stability point 2340 of view. 2341 2342 If unsure, say N. 2343 2344config TEST_USER_COPY 2345 tristate "Test user/kernel boundary protections" 2346 depends on m 2347 help 2348 This builds the "test_user_copy" module that runs sanity checks 2349 on the copy_to/from_user infrastructure, making sure basic 2350 user/kernel boundary testing is working. If it fails to load, 2351 a regression has been detected in the user/kernel memory boundary 2352 protections. 2353 2354 If unsure, say N. 2355 2356config TEST_BPF 2357 tristate "Test BPF filter functionality" 2358 depends on m && NET 2359 help 2360 This builds the "test_bpf" module that runs various test vectors 2361 against the BPF interpreter or BPF JIT compiler depending on the 2362 current setting. This is in particular useful for BPF JIT compiler 2363 development, but also to run regression tests against changes in 2364 the interpreter code. It also enables test stubs for eBPF maps and 2365 verifier used by user space verifier testsuite. 2366 2367 If unsure, say N. 2368 2369config TEST_BLACKHOLE_DEV 2370 tristate "Test blackhole netdev functionality" 2371 depends on m && NET 2372 help 2373 This builds the "test_blackhole_dev" module that validates the 2374 data path through this blackhole netdev. 2375 2376 If unsure, say N. 2377 2378config FIND_BIT_BENCHMARK 2379 tristate "Test find_bit functions" 2380 help 2381 This builds the "test_find_bit" module that measure find_*_bit() 2382 functions performance. 2383 2384 If unsure, say N. 2385 2386config TEST_FIRMWARE 2387 tristate "Test firmware loading via userspace interface" 2388 depends on FW_LOADER 2389 help 2390 This builds the "test_firmware" module that creates a userspace 2391 interface for testing firmware loading. This can be used to 2392 control the triggering of firmware loading without needing an 2393 actual firmware-using device. The contents can be rechecked by 2394 userspace. 2395 2396 If unsure, say N. 2397 2398config TEST_SYSCTL 2399 tristate "sysctl test driver" 2400 depends on PROC_SYSCTL 2401 help 2402 This builds the "test_sysctl" module. This driver enables to test the 2403 proc sysctl interfaces available to drivers safely without affecting 2404 production knobs which might alter system functionality. 2405 2406 If unsure, say N. 2407 2408config BITFIELD_KUNIT 2409 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2410 depends on KUNIT 2411 default KUNIT_ALL_TESTS 2412 help 2413 Enable this option to test the bitfield functions at boot. 2414 2415 KUnit tests run during boot and output the results to the debug log 2416 in TAP format (http://testanything.org/). Only useful for kernel devs 2417 running the KUnit test harness, and not intended for inclusion into a 2418 production build. 2419 2420 For more information on KUnit and unit tests in general please refer 2421 to the KUnit documentation in Documentation/dev-tools/kunit/. 2422 2423 If unsure, say N. 2424 2425config HASH_KUNIT_TEST 2426 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2427 depends on KUNIT 2428 default KUNIT_ALL_TESTS 2429 help 2430 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2431 integer (<linux/hash.h>) hash functions on boot. 2432 2433 KUnit tests run during boot and output the results to the debug log 2434 in TAP format (https://testanything.org/). Only useful for kernel devs 2435 running the KUnit test harness, and not intended for inclusion into a 2436 production build. 2437 2438 For more information on KUnit and unit tests in general please refer 2439 to the KUnit documentation in Documentation/dev-tools/kunit/. 2440 2441 This is intended to help people writing architecture-specific 2442 optimized versions. If unsure, say N. 2443 2444config RESOURCE_KUNIT_TEST 2445 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2446 depends on KUNIT 2447 default KUNIT_ALL_TESTS 2448 help 2449 This builds the resource API unit test. 2450 Tests the logic of API provided by resource.c and ioport.h. 2451 For more information on KUnit and unit tests in general please refer 2452 to the KUnit documentation in Documentation/dev-tools/kunit/. 2453 2454 If unsure, say N. 2455 2456config SYSCTL_KUNIT_TEST 2457 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2458 depends on KUNIT 2459 default KUNIT_ALL_TESTS 2460 help 2461 This builds the proc sysctl unit test, which runs on boot. 2462 Tests the API contract and implementation correctness of sysctl. 2463 For more information on KUnit and unit tests in general please refer 2464 to the KUnit documentation in Documentation/dev-tools/kunit/. 2465 2466 If unsure, say N. 2467 2468config LIST_KUNIT_TEST 2469 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2470 depends on KUNIT 2471 default KUNIT_ALL_TESTS 2472 help 2473 This builds the linked list KUnit test suite. 2474 It tests that the API and basic functionality of the list_head type 2475 and associated macros. 2476 2477 KUnit tests run during boot and output the results to the debug log 2478 in TAP format (https://testanything.org/). Only useful for kernel devs 2479 running the KUnit test harness, and not intended for inclusion into a 2480 production build. 2481 2482 For more information on KUnit and unit tests in general please refer 2483 to the KUnit documentation in Documentation/dev-tools/kunit/. 2484 2485 If unsure, say N. 2486 2487config HASHTABLE_KUNIT_TEST 2488 tristate "KUnit Test for Kernel Hashtable structures" if !KUNIT_ALL_TESTS 2489 depends on KUNIT 2490 default KUNIT_ALL_TESTS 2491 help 2492 This builds the hashtable KUnit test suite. 2493 It tests the basic functionality of the API defined in 2494 include/linux/hashtable.h. For more information on KUnit and 2495 unit tests in general please refer to the KUnit documentation 2496 in Documentation/dev-tools/kunit/. 2497 2498 If unsure, say N. 2499 2500config LINEAR_RANGES_TEST 2501 tristate "KUnit test for linear_ranges" 2502 depends on KUNIT 2503 select LINEAR_RANGES 2504 help 2505 This builds the linear_ranges unit test, which runs on boot. 2506 Tests the linear_ranges logic correctness. 2507 For more information on KUnit and unit tests in general please refer 2508 to the KUnit documentation in Documentation/dev-tools/kunit/. 2509 2510 If unsure, say N. 2511 2512config CMDLINE_KUNIT_TEST 2513 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2514 depends on KUNIT 2515 default KUNIT_ALL_TESTS 2516 help 2517 This builds the cmdline API unit test. 2518 Tests the logic of API provided by cmdline.c. 2519 For more information on KUnit and unit tests in general please refer 2520 to the KUnit documentation in Documentation/dev-tools/kunit/. 2521 2522 If unsure, say N. 2523 2524config BITS_TEST 2525 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2526 depends on KUNIT 2527 default KUNIT_ALL_TESTS 2528 help 2529 This builds the bits unit test. 2530 Tests the logic of macros defined in bits.h. 2531 For more information on KUnit and unit tests in general please refer 2532 to the KUnit documentation in Documentation/dev-tools/kunit/. 2533 2534 If unsure, say N. 2535 2536config SLUB_KUNIT_TEST 2537 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2538 depends on SLUB_DEBUG && KUNIT 2539 default KUNIT_ALL_TESTS 2540 help 2541 This builds SLUB allocator unit test. 2542 Tests SLUB cache debugging functionality. 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 RATIONAL_KUNIT_TEST 2549 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2550 depends on KUNIT && RATIONAL 2551 default KUNIT_ALL_TESTS 2552 help 2553 This builds the rational math unit test. 2554 For more information on KUnit and unit tests in general please refer 2555 to the KUnit documentation in Documentation/dev-tools/kunit/. 2556 2557 If unsure, say N. 2558 2559config MEMCPY_KUNIT_TEST 2560 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2561 depends on KUNIT 2562 default KUNIT_ALL_TESTS 2563 help 2564 Builds unit tests for memcpy(), memmove(), and memset() functions. 2565 For more information on KUnit and unit tests in general please refer 2566 to the KUnit documentation in Documentation/dev-tools/kunit/. 2567 2568 If unsure, say N. 2569 2570config MEMCPY_SLOW_KUNIT_TEST 2571 bool "Include exhaustive memcpy tests" 2572 depends on MEMCPY_KUNIT_TEST 2573 default y 2574 help 2575 Some memcpy tests are quite exhaustive in checking for overlaps 2576 and bit ranges. These can be very slow, so they are split out 2577 as a separate config, in case they need to be disabled. 2578 2579config IS_SIGNED_TYPE_KUNIT_TEST 2580 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2581 depends on KUNIT 2582 default KUNIT_ALL_TESTS 2583 help 2584 Builds unit tests for the is_signed_type() macro. 2585 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 OVERFLOW_KUNIT_TEST 2592 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2593 depends on KUNIT 2594 default KUNIT_ALL_TESTS 2595 help 2596 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2597 related functions. 2598 2599 For more information on KUnit and unit tests in general please refer 2600 to the KUnit documentation in Documentation/dev-tools/kunit/. 2601 2602 If unsure, say N. 2603 2604config STACKINIT_KUNIT_TEST 2605 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2606 depends on KUNIT 2607 default KUNIT_ALL_TESTS 2608 help 2609 Test if the kernel is zero-initializing stack variables and 2610 padding. Coverage is controlled by compiler flags, 2611 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2612 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2613 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2614 2615config FORTIFY_KUNIT_TEST 2616 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2617 depends on KUNIT && FORTIFY_SOURCE 2618 default KUNIT_ALL_TESTS 2619 help 2620 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2621 by the str*() and mem*() family of functions. For testing runtime 2622 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2623 2624config HW_BREAKPOINT_KUNIT_TEST 2625 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2626 depends on HAVE_HW_BREAKPOINT 2627 depends on KUNIT=y 2628 default KUNIT_ALL_TESTS 2629 help 2630 Tests for hw_breakpoint constraints accounting. 2631 2632 If unsure, say N. 2633 2634config STRSCPY_KUNIT_TEST 2635 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2636 depends on KUNIT 2637 default KUNIT_ALL_TESTS 2638 2639config SIPHASH_KUNIT_TEST 2640 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2641 depends on KUNIT 2642 default KUNIT_ALL_TESTS 2643 help 2644 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2645 functions on boot (or module load). 2646 2647 This is intended to help people writing architecture-specific 2648 optimized versions. If unsure, say N. 2649 2650config TEST_UDELAY 2651 tristate "udelay test driver" 2652 help 2653 This builds the "udelay_test" module that helps to make sure 2654 that udelay() is working properly. 2655 2656 If unsure, say N. 2657 2658config TEST_STATIC_KEYS 2659 tristate "Test static keys" 2660 depends on m 2661 help 2662 Test the static key interfaces. 2663 2664 If unsure, say N. 2665 2666config TEST_DYNAMIC_DEBUG 2667 tristate "Test DYNAMIC_DEBUG" 2668 depends on DYNAMIC_DEBUG 2669 help 2670 This module registers a tracer callback to count enabled 2671 pr_debugs in a 'do_debugging' function, then alters their 2672 enablements, calls the function, and compares counts. 2673 2674 If unsure, say N. 2675 2676config TEST_KMOD 2677 tristate "kmod stress tester" 2678 depends on m 2679 depends on NETDEVICES && NET_CORE && INET # for TUN 2680 depends on BLOCK 2681 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2682 select TEST_LKM 2683 select XFS_FS 2684 select TUN 2685 select BTRFS_FS 2686 help 2687 Test the kernel's module loading mechanism: kmod. kmod implements 2688 support to load modules using the Linux kernel's usermode helper. 2689 This test provides a series of tests against kmod. 2690 2691 Although technically you can either build test_kmod as a module or 2692 into the kernel we disallow building it into the kernel since 2693 it stress tests request_module() and this will very likely cause 2694 some issues by taking over precious threads available from other 2695 module load requests, ultimately this could be fatal. 2696 2697 To run tests run: 2698 2699 tools/testing/selftests/kmod/kmod.sh --help 2700 2701 If unsure, say N. 2702 2703config TEST_DEBUG_VIRTUAL 2704 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2705 depends on DEBUG_VIRTUAL 2706 help 2707 Test the kernel's ability to detect incorrect calls to 2708 virt_to_phys() done against the non-linear part of the 2709 kernel's virtual address map. 2710 2711 If unsure, say N. 2712 2713config TEST_MEMCAT_P 2714 tristate "Test memcat_p() helper function" 2715 help 2716 Test the memcat_p() helper for correctly merging two 2717 pointer arrays together. 2718 2719 If unsure, say N. 2720 2721config TEST_LIVEPATCH 2722 tristate "Test livepatching" 2723 default n 2724 depends on DYNAMIC_DEBUG 2725 depends on LIVEPATCH 2726 depends on m 2727 help 2728 Test kernel livepatching features for correctness. The tests will 2729 load test modules that will be livepatched in various scenarios. 2730 2731 To run all the livepatching tests: 2732 2733 make -C tools/testing/selftests TARGETS=livepatch run_tests 2734 2735 Alternatively, individual tests may be invoked: 2736 2737 tools/testing/selftests/livepatch/test-callbacks.sh 2738 tools/testing/selftests/livepatch/test-livepatch.sh 2739 tools/testing/selftests/livepatch/test-shadow-vars.sh 2740 2741 If unsure, say N. 2742 2743config TEST_OBJAGG 2744 tristate "Perform selftest on object aggreration manager" 2745 default n 2746 depends on OBJAGG 2747 help 2748 Enable this option to test object aggregation manager on boot 2749 (or module load). 2750 2751config TEST_MEMINIT 2752 tristate "Test heap/page initialization" 2753 help 2754 Test if the kernel is zero-initializing heap and page allocations. 2755 This can be useful to test init_on_alloc and init_on_free features. 2756 2757 If unsure, say N. 2758 2759config TEST_HMM 2760 tristate "Test HMM (Heterogeneous Memory Management)" 2761 depends on TRANSPARENT_HUGEPAGE 2762 depends on DEVICE_PRIVATE 2763 select HMM_MIRROR 2764 select MMU_NOTIFIER 2765 help 2766 This is a pseudo device driver solely for testing HMM. 2767 Say M here if you want to build the HMM test module. 2768 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2769 2770 If unsure, say N. 2771 2772config TEST_FREE_PAGES 2773 tristate "Test freeing pages" 2774 help 2775 Test that a memory leak does not occur due to a race between 2776 freeing a block of pages and a speculative page reference. 2777 Loading this module is safe if your kernel has the bug fixed. 2778 If the bug is not fixed, it will leak gigabytes of memory and 2779 probably OOM your system. 2780 2781config TEST_FPU 2782 tristate "Test floating point operations in kernel space" 2783 depends on X86 && !KCOV_INSTRUMENT_ALL 2784 help 2785 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2786 which will trigger a sequence of floating point operations. This is used 2787 for self-testing floating point control register setting in 2788 kernel_fpu_begin(). 2789 2790 If unsure, say N. 2791 2792config TEST_CLOCKSOURCE_WATCHDOG 2793 tristate "Test clocksource watchdog in kernel space" 2794 depends on CLOCKSOURCE_WATCHDOG 2795 help 2796 Enable this option to create a kernel module that will trigger 2797 a test of the clocksource watchdog. This module may be loaded 2798 via modprobe or insmod in which case it will run upon being 2799 loaded, or it may be built in, in which case it will run 2800 shortly after boot. 2801 2802 If unsure, say N. 2803 2804endif # RUNTIME_TESTING_MENU 2805 2806config ARCH_USE_MEMTEST 2807 bool 2808 help 2809 An architecture should select this when it uses early_memtest() 2810 during boot process. 2811 2812config MEMTEST 2813 bool "Memtest" 2814 depends on ARCH_USE_MEMTEST 2815 help 2816 This option adds a kernel parameter 'memtest', which allows memtest 2817 to be set and executed. 2818 memtest=0, mean disabled; -- default 2819 memtest=1, mean do 1 test pattern; 2820 ... 2821 memtest=17, mean do 17 test patterns. 2822 If you are unsure how to answer this question, answer N. 2823 2824 2825 2826config HYPERV_TESTING 2827 bool "Microsoft Hyper-V driver testing" 2828 default n 2829 depends on HYPERV && DEBUG_FS 2830 help 2831 Select this option to enable Hyper-V vmbus testing. 2832 2833endmenu # "Kernel Testing and Coverage" 2834 2835menu "Rust hacking" 2836 2837config RUST_DEBUG_ASSERTIONS 2838 bool "Debug assertions" 2839 depends on RUST 2840 help 2841 Enables rustc's `-Cdebug-assertions` codegen option. 2842 2843 This flag lets you turn `cfg(debug_assertions)` conditional 2844 compilation on or off. This can be used to enable extra debugging 2845 code in development but not in production. For example, it controls 2846 the behavior of the standard library's `debug_assert!` macro. 2847 2848 Note that this will apply to all Rust code, including `core`. 2849 2850 If unsure, say N. 2851 2852config RUST_OVERFLOW_CHECKS 2853 bool "Overflow checks" 2854 default y 2855 depends on RUST 2856 help 2857 Enables rustc's `-Coverflow-checks` codegen option. 2858 2859 This flag allows you to control the behavior of runtime integer 2860 overflow. When overflow-checks are enabled, a Rust panic will occur 2861 on overflow. 2862 2863 Note that this will apply to all Rust code, including `core`. 2864 2865 If unsure, say Y. 2866 2867config RUST_BUILD_ASSERT_ALLOW 2868 bool "Allow unoptimized build-time assertions" 2869 depends on RUST 2870 help 2871 Controls how are `build_error!` and `build_assert!` handled during build. 2872 2873 If calls to them exist in the binary, it may indicate a violated invariant 2874 or that the optimizer failed to verify the invariant during compilation. 2875 2876 This should not happen, thus by default the build is aborted. However, 2877 as an escape hatch, you can choose Y here to ignore them during build 2878 and let the check be carried at runtime (with `panic!` being called if 2879 the check fails). 2880 2881 If unsure, say N. 2882 2883endmenu # "Rust" 2884 2885endmenu # Kernel hacking 2886