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 DEBUG_INFO_BTF_MODULES 393 def_bool y 394 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 395 help 396 Generate compact split BTF type information for kernel modules. 397 398config MODULE_ALLOW_BTF_MISMATCH 399 bool "Allow loading modules with non-matching BTF type info" 400 depends on DEBUG_INFO_BTF_MODULES 401 help 402 For modules whose split BTF does not match vmlinux, load without 403 BTF rather than refusing to load. The default behavior with 404 module BTF enabled is to reject modules with such mismatches; 405 this option will still load module BTF where possible but ignore 406 it when a mismatch is found. 407 408config GDB_SCRIPTS 409 bool "Provide GDB scripts for kernel debugging" 410 help 411 This creates the required links to GDB helper scripts in the 412 build directory. If you load vmlinux into gdb, the helper 413 scripts will be automatically imported by gdb as well, and 414 additional functions are available to analyze a Linux kernel 415 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 416 for further details. 417 418endif # DEBUG_INFO 419 420config FRAME_WARN 421 int "Warn for stack frames larger than" 422 range 0 8192 423 default 0 if KMSAN 424 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 425 default 2048 if PARISC 426 default 1536 if (!64BIT && XTENSA) 427 default 1280 if KASAN && !64BIT 428 default 1024 if !64BIT 429 default 2048 if 64BIT 430 help 431 Tell the compiler to warn at build time for stack frames larger than this. 432 Setting this too low will cause a lot of warnings. 433 Setting it to 0 disables the warning. 434 435config STRIP_ASM_SYMS 436 bool "Strip assembler-generated symbols during link" 437 default n 438 help 439 Strip internal assembler-generated symbols during a link (symbols 440 that look like '.Lxxx') so they don't pollute the output of 441 get_wchan() and suchlike. 442 443config READABLE_ASM 444 bool "Generate readable assembler code" 445 depends on DEBUG_KERNEL 446 depends on CC_IS_GCC 447 help 448 Disable some compiler optimizations that tend to generate human unreadable 449 assembler output. This may make the kernel slightly slower, but it helps 450 to keep kernel developers who have to stare a lot at assembler listings 451 sane. 452 453config HEADERS_INSTALL 454 bool "Install uapi headers to usr/include" 455 depends on !UML 456 help 457 This option will install uapi headers (headers exported to user-space) 458 into the usr/include directory for use during the kernel build. 459 This is unneeded for building the kernel itself, but needed for some 460 user-space program samples. It is also needed by some features such 461 as uapi header sanity checks. 462 463config DEBUG_SECTION_MISMATCH 464 bool "Enable full Section mismatch analysis" 465 depends on CC_IS_GCC 466 help 467 The section mismatch analysis checks if there are illegal 468 references from one section to another section. 469 During linktime or runtime, some sections are dropped; 470 any use of code/data previously in these sections would 471 most likely result in an oops. 472 In the code, functions and variables are annotated with 473 __init,, etc. (see the full list in include/linux/init.h), 474 which results in the code/data being placed in specific sections. 475 The section mismatch analysis is always performed after a full 476 kernel build, and enabling this option causes the following 477 additional step to occur: 478 - Add the option -fno-inline-functions-called-once to gcc commands. 479 When inlining a function annotated with __init in a non-init 480 function, we would lose the section information and thus 481 the analysis would not catch the illegal reference. 482 This option tells gcc to inline less (but it does result in 483 a larger kernel). 484 485config SECTION_MISMATCH_WARN_ONLY 486 bool "Make section mismatch errors non-fatal" 487 default y 488 help 489 If you say N here, the build process will fail if there are any 490 section mismatch, instead of just throwing warnings. 491 492 If unsure, say Y. 493 494config DEBUG_FORCE_FUNCTION_ALIGN_64B 495 bool "Force all function address 64B aligned" 496 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 497 select FUNCTION_ALIGNMENT_64B 498 help 499 There are cases that a commit from one domain changes the function 500 address alignment of other domains, and cause magic performance 501 bump (regression or improvement). Enable this option will help to 502 verify if the bump is caused by function alignment changes, while 503 it will slightly increase the kernel size and affect icache usage. 504 505 It is mainly for debug and performance tuning use. 506 507# 508# Select this config option from the architecture Kconfig, if it 509# is preferred to always offer frame pointers as a config 510# option on the architecture (regardless of KERNEL_DEBUG): 511# 512config ARCH_WANT_FRAME_POINTERS 513 bool 514 515config FRAME_POINTER 516 bool "Compile the kernel with frame pointers" 517 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 518 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 519 help 520 If you say Y here the resulting kernel image will be slightly 521 larger and slower, but it gives very useful debugging information 522 in case of kernel bugs. (precise oopses/stacktraces/warnings) 523 524config OBJTOOL 525 bool 526 527config STACK_VALIDATION 528 bool "Compile-time stack metadata validation" 529 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 530 select OBJTOOL 531 default n 532 help 533 Validate frame pointer rules at compile-time. This helps ensure that 534 runtime stack traces are more reliable. 535 536 For more information, see 537 tools/objtool/Documentation/objtool.txt. 538 539config NOINSTR_VALIDATION 540 bool 541 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 542 select OBJTOOL 543 default y 544 545config VMLINUX_MAP 546 bool "Generate vmlinux.map file when linking" 547 depends on EXPERT 548 help 549 Selecting this option will pass "-Map=vmlinux.map" to ld 550 when linking vmlinux. That file can be useful for verifying 551 and debugging magic section games, and for seeing which 552 pieces of code get eliminated with 553 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 554 555config DEBUG_FORCE_WEAK_PER_CPU 556 bool "Force weak per-cpu definitions" 557 depends on DEBUG_KERNEL 558 help 559 s390 and alpha require percpu variables in modules to be 560 defined weak to work around addressing range issue which 561 puts the following two restrictions on percpu variable 562 definitions. 563 564 1. percpu symbols must be unique whether static or not 565 2. percpu variables can't be defined inside a function 566 567 To ensure that generic code follows the above rules, this 568 option forces all percpu variables to be defined as weak. 569 570endmenu # "Compiler options" 571 572menu "Generic Kernel Debugging Instruments" 573 574config MAGIC_SYSRQ 575 bool "Magic SysRq key" 576 depends on !UML 577 help 578 If you say Y here, you will have some control over the system even 579 if the system crashes for example during kernel debugging (e.g., you 580 will be able to flush the buffer cache to disk, reboot the system 581 immediately or dump some status information). This is accomplished 582 by pressing various keys while holding SysRq (Alt+PrintScreen). It 583 also works on a serial console (on PC hardware at least), if you 584 send a BREAK and then within 5 seconds a command keypress. The 585 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 586 Don't say Y unless you really know what this hack does. 587 588config MAGIC_SYSRQ_DEFAULT_ENABLE 589 hex "Enable magic SysRq key functions by default" 590 depends on MAGIC_SYSRQ 591 default 0x1 592 help 593 Specifies which SysRq key functions are enabled by default. 594 This may be set to 1 or 0 to enable or disable them all, or 595 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 596 597config MAGIC_SYSRQ_SERIAL 598 bool "Enable magic SysRq key over serial" 599 depends on MAGIC_SYSRQ 600 default y 601 help 602 Many embedded boards have a disconnected TTL level serial which can 603 generate some garbage that can lead to spurious false sysrq detects. 604 This option allows you to decide whether you want to enable the 605 magic SysRq key. 606 607config MAGIC_SYSRQ_SERIAL_SEQUENCE 608 string "Char sequence that enables magic SysRq over serial" 609 depends on MAGIC_SYSRQ_SERIAL 610 default "" 611 help 612 Specifies a sequence of characters that can follow BREAK to enable 613 SysRq on a serial console. 614 615 If unsure, leave an empty string and the option will not be enabled. 616 617config DEBUG_FS 618 bool "Debug Filesystem" 619 help 620 debugfs is a virtual file system that kernel developers use to put 621 debugging files into. Enable this option to be able to read and 622 write to these files. 623 624 For detailed documentation on the debugfs API, see 625 Documentation/filesystems/. 626 627 If unsure, say N. 628 629choice 630 prompt "Debugfs default access" 631 depends on DEBUG_FS 632 default DEBUG_FS_ALLOW_ALL 633 help 634 This selects the default access restrictions for debugfs. 635 It can be overridden with kernel command line option 636 debugfs=[on,no-mount,off]. The restrictions apply for API access 637 and filesystem registration. 638 639config DEBUG_FS_ALLOW_ALL 640 bool "Access normal" 641 help 642 No restrictions apply. Both API and filesystem registration 643 is on. This is the normal default operation. 644 645config DEBUG_FS_DISALLOW_MOUNT 646 bool "Do not register debugfs as filesystem" 647 help 648 The API is open but filesystem is not loaded. Clients can still do 649 their work and read with debug tools that do not need 650 debugfs filesystem. 651 652config DEBUG_FS_ALLOW_NONE 653 bool "No access" 654 help 655 Access is off. Clients get -PERM when trying to create nodes in 656 debugfs tree and debugfs is not registered as a filesystem. 657 Client can then back-off or continue without debugfs access. 658 659endchoice 660 661source "lib/Kconfig.kgdb" 662source "lib/Kconfig.ubsan" 663source "lib/Kconfig.kcsan" 664 665endmenu 666 667menu "Networking Debugging" 668 669source "net/Kconfig.debug" 670 671endmenu # "Networking Debugging" 672 673menu "Memory Debugging" 674 675source "mm/Kconfig.debug" 676 677config DEBUG_OBJECTS 678 bool "Debug object operations" 679 depends on DEBUG_KERNEL 680 help 681 If you say Y here, additional code will be inserted into the 682 kernel to track the life time of various objects and validate 683 the operations on those objects. 684 685config DEBUG_OBJECTS_SELFTEST 686 bool "Debug objects selftest" 687 depends on DEBUG_OBJECTS 688 help 689 This enables the selftest of the object debug code. 690 691config DEBUG_OBJECTS_FREE 692 bool "Debug objects in freed memory" 693 depends on DEBUG_OBJECTS 694 help 695 This enables checks whether a k/v free operation frees an area 696 which contains an object which has not been deactivated 697 properly. This can make kmalloc/kfree-intensive workloads 698 much slower. 699 700config DEBUG_OBJECTS_TIMERS 701 bool "Debug timer objects" 702 depends on DEBUG_OBJECTS 703 help 704 If you say Y here, additional code will be inserted into the 705 timer routines to track the life time of timer objects and 706 validate the timer operations. 707 708config DEBUG_OBJECTS_WORK 709 bool "Debug work objects" 710 depends on DEBUG_OBJECTS 711 help 712 If you say Y here, additional code will be inserted into the 713 work queue routines to track the life time of work objects and 714 validate the work operations. 715 716config DEBUG_OBJECTS_RCU_HEAD 717 bool "Debug RCU callbacks objects" 718 depends on DEBUG_OBJECTS 719 help 720 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 721 722config DEBUG_OBJECTS_PERCPU_COUNTER 723 bool "Debug percpu counter objects" 724 depends on DEBUG_OBJECTS 725 help 726 If you say Y here, additional code will be inserted into the 727 percpu counter routines to track the life time of percpu counter 728 objects and validate the percpu counter operations. 729 730config DEBUG_OBJECTS_ENABLE_DEFAULT 731 int "debug_objects bootup default value (0-1)" 732 range 0 1 733 default "1" 734 depends on DEBUG_OBJECTS 735 help 736 Debug objects boot parameter default value 737 738config SHRINKER_DEBUG 739 bool "Enable shrinker debugging support" 740 depends on DEBUG_FS 741 help 742 Say Y to enable the shrinker debugfs interface which provides 743 visibility into the kernel memory shrinkers subsystem. 744 Disable it to avoid an extra memory footprint. 745 746config HAVE_DEBUG_KMEMLEAK 747 bool 748 749config DEBUG_KMEMLEAK 750 bool "Kernel memory leak detector" 751 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 752 select DEBUG_FS 753 select STACKTRACE if STACKTRACE_SUPPORT 754 select KALLSYMS 755 select CRC32 756 select STACKDEPOT 757 help 758 Say Y here if you want to enable the memory leak 759 detector. The memory allocation/freeing is traced in a way 760 similar to the Boehm's conservative garbage collector, the 761 difference being that the orphan objects are not freed but 762 only shown in /sys/kernel/debug/kmemleak. Enabling this 763 feature will introduce an overhead to memory 764 allocations. See Documentation/dev-tools/kmemleak.rst for more 765 details. 766 767 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 768 of finding leaks due to the slab objects poisoning. 769 770 In order to access the kmemleak file, debugfs needs to be 771 mounted (usually at /sys/kernel/debug). 772 773config DEBUG_KMEMLEAK_MEM_POOL_SIZE 774 int "Kmemleak memory pool size" 775 depends on DEBUG_KMEMLEAK 776 range 200 1000000 777 default 16000 778 help 779 Kmemleak must track all the memory allocations to avoid 780 reporting false positives. Since memory may be allocated or 781 freed before kmemleak is fully initialised, use a static pool 782 of metadata objects to track such callbacks. After kmemleak is 783 fully initialised, this memory pool acts as an emergency one 784 if slab allocations fail. 785 786config DEBUG_KMEMLEAK_TEST 787 tristate "Simple test for the kernel memory leak detector" 788 depends on DEBUG_KMEMLEAK && m 789 help 790 This option enables a module that explicitly leaks memory. 791 792 If unsure, say N. 793 794config DEBUG_KMEMLEAK_DEFAULT_OFF 795 bool "Default kmemleak to off" 796 depends on DEBUG_KMEMLEAK 797 help 798 Say Y here to disable kmemleak by default. It can then be enabled 799 on the command line via kmemleak=on. 800 801config DEBUG_KMEMLEAK_AUTO_SCAN 802 bool "Enable kmemleak auto scan thread on boot up" 803 default y 804 depends on DEBUG_KMEMLEAK 805 help 806 Depending on the cpu, kmemleak scan may be cpu intensive and can 807 stall user tasks at times. This option enables/disables automatic 808 kmemleak scan at boot up. 809 810 Say N here to disable kmemleak auto scan thread to stop automatic 811 scanning. Disabling this option disables automatic reporting of 812 memory leaks. 813 814 If unsure, say Y. 815 816config DEBUG_STACK_USAGE 817 bool "Stack utilization instrumentation" 818 depends on DEBUG_KERNEL && !IA64 819 help 820 Enables the display of the minimum amount of free stack which each 821 task has ever had available in the sysrq-T and sysrq-P debug output. 822 823 This option will slow down process creation somewhat. 824 825config SCHED_STACK_END_CHECK 826 bool "Detect stack corruption on calls to schedule()" 827 depends on DEBUG_KERNEL 828 default n 829 help 830 This option checks for a stack overrun on calls to schedule(). 831 If the stack end location is found to be over written always panic as 832 the content of the corrupted region can no longer be trusted. 833 This is to ensure no erroneous behaviour occurs which could result in 834 data corruption or a sporadic crash at a later stage once the region 835 is examined. The runtime overhead introduced is minimal. 836 837config ARCH_HAS_DEBUG_VM_PGTABLE 838 bool 839 help 840 An architecture should select this when it can successfully 841 build and run DEBUG_VM_PGTABLE. 842 843config DEBUG_VM_IRQSOFF 844 def_bool DEBUG_VM && !PREEMPT_RT 845 846config DEBUG_VM 847 bool "Debug VM" 848 depends on DEBUG_KERNEL 849 help 850 Enable this to turn on extended checks in the virtual-memory system 851 that may impact performance. 852 853 If unsure, say N. 854 855config DEBUG_VM_MAPLE_TREE 856 bool "Debug VM maple trees" 857 depends on DEBUG_VM 858 select DEBUG_MAPLE_TREE 859 help 860 Enable VM maple tree debugging information and extra validations. 861 862 If unsure, say N. 863 864config DEBUG_VM_RB 865 bool "Debug VM red-black trees" 866 depends on DEBUG_VM 867 help 868 Enable VM red-black tree debugging information and extra validations. 869 870 If unsure, say N. 871 872config DEBUG_VM_PGFLAGS 873 bool "Debug page-flags operations" 874 depends on DEBUG_VM 875 help 876 Enables extra validation on page flags operations. 877 878 If unsure, say N. 879 880config DEBUG_VM_PGTABLE 881 bool "Debug arch page table for semantics compliance" 882 depends on MMU 883 depends on ARCH_HAS_DEBUG_VM_PGTABLE 884 default y if DEBUG_VM 885 help 886 This option provides a debug method which can be used to test 887 architecture page table helper functions on various platforms in 888 verifying if they comply with expected generic MM semantics. This 889 will help architecture code in making sure that any changes or 890 new additions of these helpers still conform to expected 891 semantics of the generic MM. Platforms will have to opt in for 892 this through ARCH_HAS_DEBUG_VM_PGTABLE. 893 894 If unsure, say N. 895 896config ARCH_HAS_DEBUG_VIRTUAL 897 bool 898 899config DEBUG_VIRTUAL 900 bool "Debug VM translations" 901 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 902 help 903 Enable some costly sanity checks in virtual to page code. This can 904 catch mistakes with virt_to_page() and friends. 905 906 If unsure, say N. 907 908config DEBUG_NOMMU_REGIONS 909 bool "Debug the global anon/private NOMMU mapping region tree" 910 depends on DEBUG_KERNEL && !MMU 911 help 912 This option causes the global tree of anonymous and private mapping 913 regions to be regularly checked for invalid topology. 914 915config DEBUG_MEMORY_INIT 916 bool "Debug memory initialisation" if EXPERT 917 default !EXPERT 918 help 919 Enable this for additional checks during memory initialisation. 920 The sanity checks verify aspects of the VM such as the memory model 921 and other information provided by the architecture. Verbose 922 information will be printed at KERN_DEBUG loglevel depending 923 on the mminit_loglevel= command-line option. 924 925 If unsure, say Y 926 927config MEMORY_NOTIFIER_ERROR_INJECT 928 tristate "Memory hotplug notifier error injection module" 929 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 930 help 931 This option provides the ability to inject artificial errors to 932 memory hotplug notifier chain callbacks. It is controlled through 933 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 934 935 If the notifier call chain should be failed with some events 936 notified, write the error code to "actions/<notifier event>/error". 937 938 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 939 940 # cd /sys/kernel/debug/notifier-error-inject/memory 941 # echo -12 > actions/MEM_GOING_OFFLINE/error 942 # echo offline > /sys/devices/system/memory/memoryXXX/state 943 bash: echo: write error: Cannot allocate memory 944 945 To compile this code as a module, choose M here: the module will 946 be called memory-notifier-error-inject. 947 948 If unsure, say N. 949 950config DEBUG_PER_CPU_MAPS 951 bool "Debug access to per_cpu maps" 952 depends on DEBUG_KERNEL 953 depends on SMP 954 help 955 Say Y to verify that the per_cpu map being accessed has 956 been set up. This adds a fair amount of code to kernel memory 957 and decreases performance. 958 959 Say N if unsure. 960 961config DEBUG_KMAP_LOCAL 962 bool "Debug kmap_local temporary mappings" 963 depends on DEBUG_KERNEL && KMAP_LOCAL 964 help 965 This option enables additional error checking for the kmap_local 966 infrastructure. Disable for production use. 967 968config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 969 bool 970 971config DEBUG_KMAP_LOCAL_FORCE_MAP 972 bool "Enforce kmap_local temporary mappings" 973 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 974 select KMAP_LOCAL 975 select DEBUG_KMAP_LOCAL 976 help 977 This option enforces temporary mappings through the kmap_local 978 mechanism for non-highmem pages and on non-highmem systems. 979 Disable this for production systems! 980 981config DEBUG_HIGHMEM 982 bool "Highmem debugging" 983 depends on DEBUG_KERNEL && HIGHMEM 984 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 985 select DEBUG_KMAP_LOCAL 986 help 987 This option enables additional error checking for high memory 988 systems. Disable for production systems. 989 990config HAVE_DEBUG_STACKOVERFLOW 991 bool 992 993config DEBUG_STACKOVERFLOW 994 bool "Check for stack overflows" 995 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 996 help 997 Say Y here if you want to check for overflows of kernel, IRQ 998 and exception stacks (if your architecture uses them). This 999 option will show detailed messages if free stack space drops 1000 below a certain limit. 1001 1002 These kinds of bugs usually occur when call-chains in the 1003 kernel get too deep, especially when interrupts are 1004 involved. 1005 1006 Use this in cases where you see apparently random memory 1007 corruption, especially if it appears in 'struct thread_info' 1008 1009 If in doubt, say "N". 1010 1011source "lib/Kconfig.kasan" 1012source "lib/Kconfig.kfence" 1013source "lib/Kconfig.kmsan" 1014 1015endmenu # "Memory Debugging" 1016 1017config DEBUG_SHIRQ 1018 bool "Debug shared IRQ handlers" 1019 depends on DEBUG_KERNEL 1020 help 1021 Enable this to generate a spurious interrupt just before a shared 1022 interrupt handler is deregistered (generating one when registering 1023 is currently disabled). Drivers need to handle this correctly. Some 1024 don't and need to be caught. 1025 1026menu "Debug Oops, Lockups and Hangs" 1027 1028config PANIC_ON_OOPS 1029 bool "Panic on Oops" 1030 help 1031 Say Y here to enable the kernel to panic when it oopses. This 1032 has the same effect as setting oops=panic on the kernel command 1033 line. 1034 1035 This feature is useful to ensure that the kernel does not do 1036 anything erroneous after an oops which could result in data 1037 corruption or other issues. 1038 1039 Say N if unsure. 1040 1041config PANIC_ON_OOPS_VALUE 1042 int 1043 range 0 1 1044 default 0 if !PANIC_ON_OOPS 1045 default 1 if PANIC_ON_OOPS 1046 1047config PANIC_TIMEOUT 1048 int "panic timeout" 1049 default 0 1050 help 1051 Set the timeout value (in seconds) until a reboot occurs when 1052 the kernel panics. If n = 0, then we wait forever. A timeout 1053 value n > 0 will wait n seconds before rebooting, while a timeout 1054 value n < 0 will reboot immediately. 1055 1056config LOCKUP_DETECTOR 1057 bool 1058 1059config SOFTLOCKUP_DETECTOR 1060 bool "Detect Soft Lockups" 1061 depends on DEBUG_KERNEL && !S390 1062 select LOCKUP_DETECTOR 1063 help 1064 Say Y here to enable the kernel to act as a watchdog to detect 1065 soft lockups. 1066 1067 Softlockups are bugs that cause the kernel to loop in kernel 1068 mode for more than 20 seconds, without giving other tasks a 1069 chance to run. The current stack trace is displayed upon 1070 detection and the system will stay locked up. 1071 1072config BOOTPARAM_SOFTLOCKUP_PANIC 1073 bool "Panic (Reboot) On Soft Lockups" 1074 depends on SOFTLOCKUP_DETECTOR 1075 help 1076 Say Y here to enable the kernel to panic on "soft lockups", 1077 which are bugs that cause the kernel to loop in kernel 1078 mode for more than 20 seconds (configurable using the watchdog_thresh 1079 sysctl), without giving other tasks a chance to run. 1080 1081 The panic can be used in combination with panic_timeout, 1082 to cause the system to reboot automatically after a 1083 lockup has been detected. This feature is useful for 1084 high-availability systems that have uptime guarantees and 1085 where a lockup must be resolved ASAP. 1086 1087 Say N if unsure. 1088 1089config HARDLOCKUP_DETECTOR_PERF 1090 bool 1091 select SOFTLOCKUP_DETECTOR 1092 1093# 1094# Enables a timestamp based low pass filter to compensate for perf based 1095# hard lockup detection which runs too fast due to turbo modes. 1096# 1097config HARDLOCKUP_CHECK_TIMESTAMP 1098 bool 1099 1100# 1101# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1102# lockup detector rather than the perf based detector. 1103# 1104config HARDLOCKUP_DETECTOR 1105 bool "Detect Hard Lockups" 1106 depends on DEBUG_KERNEL && !S390 1107 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1108 select LOCKUP_DETECTOR 1109 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1110 help 1111 Say Y here to enable the kernel to act as a watchdog to detect 1112 hard lockups. 1113 1114 Hardlockups are bugs that cause the CPU to loop in kernel mode 1115 for more than 10 seconds, without letting other interrupts have a 1116 chance to run. The current stack trace is displayed upon detection 1117 and the system will stay locked up. 1118 1119config BOOTPARAM_HARDLOCKUP_PANIC 1120 bool "Panic (Reboot) On Hard Lockups" 1121 depends on HARDLOCKUP_DETECTOR 1122 help 1123 Say Y here to enable the kernel to panic on "hard lockups", 1124 which are bugs that cause the kernel to loop in kernel 1125 mode with interrupts disabled for more than 10 seconds (configurable 1126 using the watchdog_thresh sysctl). 1127 1128 Say N if unsure. 1129 1130config DETECT_HUNG_TASK 1131 bool "Detect Hung Tasks" 1132 depends on DEBUG_KERNEL 1133 default SOFTLOCKUP_DETECTOR 1134 help 1135 Say Y here to enable the kernel to detect "hung tasks", 1136 which are bugs that cause the task to be stuck in 1137 uninterruptible "D" state indefinitely. 1138 1139 When a hung task is detected, the kernel will print the 1140 current stack trace (which you should report), but the 1141 task will stay in uninterruptible state. If lockdep is 1142 enabled then all held locks will also be reported. This 1143 feature has negligible overhead. 1144 1145config DEFAULT_HUNG_TASK_TIMEOUT 1146 int "Default timeout for hung task detection (in seconds)" 1147 depends on DETECT_HUNG_TASK 1148 default 120 1149 help 1150 This option controls the default timeout (in seconds) used 1151 to determine when a task has become non-responsive and should 1152 be considered hung. 1153 1154 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1155 sysctl or by writing a value to 1156 /proc/sys/kernel/hung_task_timeout_secs. 1157 1158 A timeout of 0 disables the check. The default is two minutes. 1159 Keeping the default should be fine in most cases. 1160 1161config BOOTPARAM_HUNG_TASK_PANIC 1162 bool "Panic (Reboot) On Hung Tasks" 1163 depends on DETECT_HUNG_TASK 1164 help 1165 Say Y here to enable the kernel to panic on "hung tasks", 1166 which are bugs that cause the kernel to leave a task stuck 1167 in uninterruptible "D" state. 1168 1169 The panic can be used in combination with panic_timeout, 1170 to cause the system to reboot automatically after a 1171 hung task has been detected. This feature is useful for 1172 high-availability systems that have uptime guarantees and 1173 where a hung tasks must be resolved ASAP. 1174 1175 Say N if unsure. 1176 1177config WQ_WATCHDOG 1178 bool "Detect Workqueue Stalls" 1179 depends on DEBUG_KERNEL 1180 help 1181 Say Y here to enable stall detection on workqueues. If a 1182 worker pool doesn't make forward progress on a pending work 1183 item for over a given amount of time, 30s by default, a 1184 warning message is printed along with dump of workqueue 1185 state. This can be configured through kernel parameter 1186 "workqueue.watchdog_thresh" and its sysfs counterpart. 1187 1188config TEST_LOCKUP 1189 tristate "Test module to generate lockups" 1190 depends on m 1191 help 1192 This builds the "test_lockup" module that helps to make sure 1193 that watchdogs and lockup detectors are working properly. 1194 1195 Depending on module parameters it could emulate soft or hard 1196 lockup, "hung task", or locking arbitrary lock for a long time. 1197 Also it could generate series of lockups with cooling-down periods. 1198 1199 If unsure, say N. 1200 1201endmenu # "Debug lockups and hangs" 1202 1203menu "Scheduler Debugging" 1204 1205config SCHED_DEBUG 1206 bool "Collect scheduler debugging info" 1207 depends on DEBUG_KERNEL && PROC_FS 1208 default y 1209 help 1210 If you say Y here, the /proc/sched_debug file will be provided 1211 that can help debug the scheduler. The runtime overhead of this 1212 option is minimal. 1213 1214config SCHED_INFO 1215 bool 1216 default n 1217 1218config SCHEDSTATS 1219 bool "Collect scheduler statistics" 1220 depends on DEBUG_KERNEL && PROC_FS 1221 select SCHED_INFO 1222 help 1223 If you say Y here, additional code will be inserted into the 1224 scheduler and related routines to collect statistics about 1225 scheduler behavior and provide them in /proc/schedstat. These 1226 stats may be useful for both tuning and debugging the scheduler 1227 If you aren't debugging the scheduler or trying to tune a specific 1228 application, you can say N to avoid the very slight overhead 1229 this adds. 1230 1231endmenu 1232 1233config DEBUG_TIMEKEEPING 1234 bool "Enable extra timekeeping sanity checking" 1235 help 1236 This option will enable additional timekeeping sanity checks 1237 which may be helpful when diagnosing issues where timekeeping 1238 problems are suspected. 1239 1240 This may include checks in the timekeeping hotpaths, so this 1241 option may have a (very small) performance impact to some 1242 workloads. 1243 1244 If unsure, say N. 1245 1246config DEBUG_PREEMPT 1247 bool "Debug preemptible kernel" 1248 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1249 default y 1250 help 1251 If you say Y here then the kernel will use a debug variant of the 1252 commonly used smp_processor_id() function and will print warnings 1253 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1254 will detect preemption count underflows. 1255 1256menu "Lock Debugging (spinlocks, mutexes, etc...)" 1257 1258config LOCK_DEBUGGING_SUPPORT 1259 bool 1260 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1261 default y 1262 1263config PROVE_LOCKING 1264 bool "Lock debugging: prove locking correctness" 1265 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1266 select LOCKDEP 1267 select DEBUG_SPINLOCK 1268 select DEBUG_MUTEXES if !PREEMPT_RT 1269 select DEBUG_RT_MUTEXES if RT_MUTEXES 1270 select DEBUG_RWSEMS 1271 select DEBUG_WW_MUTEX_SLOWPATH 1272 select DEBUG_LOCK_ALLOC 1273 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1274 select TRACE_IRQFLAGS 1275 default n 1276 help 1277 This feature enables the kernel to prove that all locking 1278 that occurs in the kernel runtime is mathematically 1279 correct: that under no circumstance could an arbitrary (and 1280 not yet triggered) combination of observed locking 1281 sequences (on an arbitrary number of CPUs, running an 1282 arbitrary number of tasks and interrupt contexts) cause a 1283 deadlock. 1284 1285 In short, this feature enables the kernel to report locking 1286 related deadlocks before they actually occur. 1287 1288 The proof does not depend on how hard and complex a 1289 deadlock scenario would be to trigger: how many 1290 participant CPUs, tasks and irq-contexts would be needed 1291 for it to trigger. The proof also does not depend on 1292 timing: if a race and a resulting deadlock is possible 1293 theoretically (no matter how unlikely the race scenario 1294 is), it will be proven so and will immediately be 1295 reported by the kernel (once the event is observed that 1296 makes the deadlock theoretically possible). 1297 1298 If a deadlock is impossible (i.e. the locking rules, as 1299 observed by the kernel, are mathematically correct), the 1300 kernel reports nothing. 1301 1302 NOTE: this feature can also be enabled for rwlocks, mutexes 1303 and rwsems - in which case all dependencies between these 1304 different locking variants are observed and mapped too, and 1305 the proof of observed correctness is also maintained for an 1306 arbitrary combination of these separate locking variants. 1307 1308 For more details, see Documentation/locking/lockdep-design.rst. 1309 1310config PROVE_RAW_LOCK_NESTING 1311 bool "Enable raw_spinlock - spinlock nesting checks" 1312 depends on PROVE_LOCKING 1313 default n 1314 help 1315 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1316 that the lock nesting rules for PREEMPT_RT enabled kernels are 1317 not violated. 1318 1319 NOTE: There are known nesting problems. So if you enable this 1320 option expect lockdep splats until these problems have been fully 1321 addressed which is work in progress. This config switch allows to 1322 identify and analyze these problems. It will be removed and the 1323 check permanently enabled once the main issues have been fixed. 1324 1325 If unsure, select N. 1326 1327config LOCK_STAT 1328 bool "Lock usage statistics" 1329 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1330 select LOCKDEP 1331 select DEBUG_SPINLOCK 1332 select DEBUG_MUTEXES if !PREEMPT_RT 1333 select DEBUG_RT_MUTEXES if RT_MUTEXES 1334 select DEBUG_LOCK_ALLOC 1335 default n 1336 help 1337 This feature enables tracking lock contention points 1338 1339 For more details, see Documentation/locking/lockstat.rst 1340 1341 This also enables lock events required by "perf lock", 1342 subcommand of perf. 1343 If you want to use "perf lock", you also need to turn on 1344 CONFIG_EVENT_TRACING. 1345 1346 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1347 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1348 1349config DEBUG_RT_MUTEXES 1350 bool "RT Mutex debugging, deadlock detection" 1351 depends on DEBUG_KERNEL && RT_MUTEXES 1352 help 1353 This allows rt mutex semantics violations and rt mutex related 1354 deadlocks (lockups) to be detected and reported automatically. 1355 1356config DEBUG_SPINLOCK 1357 bool "Spinlock and rw-lock debugging: basic checks" 1358 depends on DEBUG_KERNEL 1359 select UNINLINE_SPIN_UNLOCK 1360 help 1361 Say Y here and build SMP to catch missing spinlock initialization 1362 and certain other kinds of spinlock errors commonly made. This is 1363 best used in conjunction with the NMI watchdog so that spinlock 1364 deadlocks are also debuggable. 1365 1366config DEBUG_MUTEXES 1367 bool "Mutex debugging: basic checks" 1368 depends on DEBUG_KERNEL && !PREEMPT_RT 1369 help 1370 This feature allows mutex semantics violations to be detected and 1371 reported. 1372 1373config DEBUG_WW_MUTEX_SLOWPATH 1374 bool "Wait/wound mutex debugging: Slowpath testing" 1375 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1376 select DEBUG_LOCK_ALLOC 1377 select DEBUG_SPINLOCK 1378 select DEBUG_MUTEXES if !PREEMPT_RT 1379 select DEBUG_RT_MUTEXES if PREEMPT_RT 1380 help 1381 This feature enables slowpath testing for w/w mutex users by 1382 injecting additional -EDEADLK wound/backoff cases. Together with 1383 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1384 will test all possible w/w mutex interface abuse with the 1385 exception of simply not acquiring all the required locks. 1386 Note that this feature can introduce significant overhead, so 1387 it really should not be enabled in a production or distro kernel, 1388 even a debug kernel. If you are a driver writer, enable it. If 1389 you are a distro, do not. 1390 1391config DEBUG_RWSEMS 1392 bool "RW Semaphore debugging: basic checks" 1393 depends on DEBUG_KERNEL 1394 help 1395 This debugging feature allows mismatched rw semaphore locks 1396 and unlocks to be detected and reported. 1397 1398config DEBUG_LOCK_ALLOC 1399 bool "Lock debugging: detect incorrect freeing of live locks" 1400 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1401 select DEBUG_SPINLOCK 1402 select DEBUG_MUTEXES if !PREEMPT_RT 1403 select DEBUG_RT_MUTEXES if RT_MUTEXES 1404 select LOCKDEP 1405 help 1406 This feature will check whether any held lock (spinlock, rwlock, 1407 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1408 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1409 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1410 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1411 held during task exit. 1412 1413config LOCKDEP 1414 bool 1415 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1416 select STACKTRACE 1417 select KALLSYMS 1418 select KALLSYMS_ALL 1419 1420config LOCKDEP_SMALL 1421 bool 1422 1423config LOCKDEP_BITS 1424 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1425 depends on LOCKDEP && !LOCKDEP_SMALL 1426 range 10 30 1427 default 15 1428 help 1429 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1430 1431config LOCKDEP_CHAINS_BITS 1432 int "Bitsize for MAX_LOCKDEP_CHAINS" 1433 depends on LOCKDEP && !LOCKDEP_SMALL 1434 range 10 30 1435 default 16 1436 help 1437 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1438 1439config LOCKDEP_STACK_TRACE_BITS 1440 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1441 depends on LOCKDEP && !LOCKDEP_SMALL 1442 range 10 30 1443 default 19 1444 help 1445 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1446 1447config LOCKDEP_STACK_TRACE_HASH_BITS 1448 int "Bitsize for STACK_TRACE_HASH_SIZE" 1449 depends on LOCKDEP && !LOCKDEP_SMALL 1450 range 10 30 1451 default 14 1452 help 1453 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1454 1455config LOCKDEP_CIRCULAR_QUEUE_BITS 1456 int "Bitsize for elements in circular_queue struct" 1457 depends on LOCKDEP 1458 range 10 30 1459 default 12 1460 help 1461 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1462 1463config DEBUG_LOCKDEP 1464 bool "Lock dependency engine debugging" 1465 depends on DEBUG_KERNEL && LOCKDEP 1466 select DEBUG_IRQFLAGS 1467 help 1468 If you say Y here, the lock dependency engine will do 1469 additional runtime checks to debug itself, at the price 1470 of more runtime overhead. 1471 1472config DEBUG_ATOMIC_SLEEP 1473 bool "Sleep inside atomic section checking" 1474 select PREEMPT_COUNT 1475 depends on DEBUG_KERNEL 1476 depends on !ARCH_NO_PREEMPT 1477 help 1478 If you say Y here, various routines which may sleep will become very 1479 noisy if they are called inside atomic sections: when a spinlock is 1480 held, inside an rcu read side critical section, inside preempt disabled 1481 sections, inside an interrupt, etc... 1482 1483config DEBUG_LOCKING_API_SELFTESTS 1484 bool "Locking API boot-time self-tests" 1485 depends on DEBUG_KERNEL 1486 help 1487 Say Y here if you want the kernel to run a short self-test during 1488 bootup. The self-test checks whether common types of locking bugs 1489 are detected by debugging mechanisms or not. (if you disable 1490 lock debugging then those bugs won't be detected of course.) 1491 The following locking APIs are covered: spinlocks, rwlocks, 1492 mutexes and rwsems. 1493 1494config LOCK_TORTURE_TEST 1495 tristate "torture tests for locking" 1496 depends on DEBUG_KERNEL 1497 select TORTURE_TEST 1498 help 1499 This option provides a kernel module that runs torture tests 1500 on kernel locking primitives. The kernel module may be built 1501 after the fact on the running kernel to be tested, if desired. 1502 1503 Say Y here if you want kernel locking-primitive torture tests 1504 to be built into the kernel. 1505 Say M if you want these torture tests to build as a module. 1506 Say N if you are unsure. 1507 1508config WW_MUTEX_SELFTEST 1509 tristate "Wait/wound mutex selftests" 1510 help 1511 This option provides a kernel module that runs tests on the 1512 on the struct ww_mutex locking API. 1513 1514 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1515 with this test harness. 1516 1517 Say M if you want these self tests to build as a module. 1518 Say N if you are unsure. 1519 1520config SCF_TORTURE_TEST 1521 tristate "torture tests for smp_call_function*()" 1522 depends on DEBUG_KERNEL 1523 select TORTURE_TEST 1524 help 1525 This option provides a kernel module that runs torture tests 1526 on the smp_call_function() family of primitives. The kernel 1527 module may be built after the fact on the running kernel to 1528 be tested, if desired. 1529 1530config CSD_LOCK_WAIT_DEBUG 1531 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1532 depends on DEBUG_KERNEL 1533 depends on 64BIT 1534 default n 1535 help 1536 This option enables debug prints when CPUs are slow to respond 1537 to the smp_call_function*() IPI wrappers. These debug prints 1538 include the IPI handler function currently executing (if any) 1539 and relevant stack traces. 1540 1541endmenu # lock debugging 1542 1543config TRACE_IRQFLAGS 1544 depends on TRACE_IRQFLAGS_SUPPORT 1545 bool 1546 help 1547 Enables hooks to interrupt enabling and disabling for 1548 either tracing or lock debugging. 1549 1550config TRACE_IRQFLAGS_NMI 1551 def_bool y 1552 depends on TRACE_IRQFLAGS 1553 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1554 1555config DEBUG_IRQFLAGS 1556 bool "Debug IRQ flag manipulation" 1557 help 1558 Enables checks for potentially unsafe enabling or disabling of 1559 interrupts, such as calling raw_local_irq_restore() when interrupts 1560 are enabled. 1561 1562config STACKTRACE 1563 bool "Stack backtrace support" 1564 depends on STACKTRACE_SUPPORT 1565 help 1566 This option causes the kernel to create a /proc/pid/stack for 1567 every process, showing its current stack trace. 1568 It is also used by various kernel debugging features that require 1569 stack trace generation. 1570 1571config WARN_ALL_UNSEEDED_RANDOM 1572 bool "Warn for all uses of unseeded randomness" 1573 default n 1574 help 1575 Some parts of the kernel contain bugs relating to their use of 1576 cryptographically secure random numbers before it's actually possible 1577 to generate those numbers securely. This setting ensures that these 1578 flaws don't go unnoticed, by enabling a message, should this ever 1579 occur. This will allow people with obscure setups to know when things 1580 are going wrong, so that they might contact developers about fixing 1581 it. 1582 1583 Unfortunately, on some models of some architectures getting 1584 a fully seeded CRNG is extremely difficult, and so this can 1585 result in dmesg getting spammed for a surprisingly long 1586 time. This is really bad from a security perspective, and 1587 so architecture maintainers really need to do what they can 1588 to get the CRNG seeded sooner after the system is booted. 1589 However, since users cannot do anything actionable to 1590 address this, by default this option is disabled. 1591 1592 Say Y here if you want to receive warnings for all uses of 1593 unseeded randomness. This will be of use primarily for 1594 those developers interested in improving the security of 1595 Linux kernels running on their architecture (or 1596 subarchitecture). 1597 1598config DEBUG_KOBJECT 1599 bool "kobject debugging" 1600 depends on DEBUG_KERNEL 1601 help 1602 If you say Y here, some extra kobject debugging messages will be sent 1603 to the syslog. 1604 1605config DEBUG_KOBJECT_RELEASE 1606 bool "kobject release debugging" 1607 depends on DEBUG_OBJECTS_TIMERS 1608 help 1609 kobjects are reference counted objects. This means that their 1610 last reference count put is not predictable, and the kobject can 1611 live on past the point at which a driver decides to drop its 1612 initial reference to the kobject gained on allocation. An 1613 example of this would be a struct device which has just been 1614 unregistered. 1615 1616 However, some buggy drivers assume that after such an operation, 1617 the memory backing the kobject can be immediately freed. This 1618 goes completely against the principles of a refcounted object. 1619 1620 If you say Y here, the kernel will delay the release of kobjects 1621 on the last reference count to improve the visibility of this 1622 kind of kobject release bug. 1623 1624config HAVE_DEBUG_BUGVERBOSE 1625 bool 1626 1627menu "Debug kernel data structures" 1628 1629config DEBUG_LIST 1630 bool "Debug linked list manipulation" 1631 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1632 help 1633 Enable this to turn on extended checks in the linked-list 1634 walking routines. 1635 1636 If unsure, say N. 1637 1638config DEBUG_PLIST 1639 bool "Debug priority linked list manipulation" 1640 depends on DEBUG_KERNEL 1641 help 1642 Enable this to turn on extended checks in the priority-ordered 1643 linked-list (plist) walking routines. This checks the entire 1644 list multiple times during each manipulation. 1645 1646 If unsure, say N. 1647 1648config DEBUG_SG 1649 bool "Debug SG table operations" 1650 depends on DEBUG_KERNEL 1651 help 1652 Enable this to turn on checks on scatter-gather tables. This can 1653 help find problems with drivers that do not properly initialize 1654 their sg tables. 1655 1656 If unsure, say N. 1657 1658config DEBUG_NOTIFIERS 1659 bool "Debug notifier call chains" 1660 depends on DEBUG_KERNEL 1661 help 1662 Enable this to turn on sanity checking for notifier call chains. 1663 This is most useful for kernel developers to make sure that 1664 modules properly unregister themselves from notifier chains. 1665 This is a relatively cheap check but if you care about maximum 1666 performance, say N. 1667 1668config BUG_ON_DATA_CORRUPTION 1669 bool "Trigger a BUG when data corruption is detected" 1670 select DEBUG_LIST 1671 help 1672 Select this option if the kernel should BUG when it encounters 1673 data corruption in kernel memory structures when they get checked 1674 for validity. 1675 1676 If unsure, say N. 1677 1678config DEBUG_MAPLE_TREE 1679 bool "Debug maple trees" 1680 depends on DEBUG_KERNEL 1681 help 1682 Enable maple tree debugging information and extra validations. 1683 1684 If unsure, say N. 1685 1686endmenu 1687 1688config DEBUG_CREDENTIALS 1689 bool "Debug credential management" 1690 depends on DEBUG_KERNEL 1691 help 1692 Enable this to turn on some debug checking for credential 1693 management. The additional code keeps track of the number of 1694 pointers from task_structs to any given cred struct, and checks to 1695 see that this number never exceeds the usage count of the cred 1696 struct. 1697 1698 Furthermore, if SELinux is enabled, this also checks that the 1699 security pointer in the cred struct is never seen to be invalid. 1700 1701 If unsure, say N. 1702 1703source "kernel/rcu/Kconfig.debug" 1704 1705config DEBUG_WQ_FORCE_RR_CPU 1706 bool "Force round-robin CPU selection for unbound work items" 1707 depends on DEBUG_KERNEL 1708 default n 1709 help 1710 Workqueue used to implicitly guarantee that work items queued 1711 without explicit CPU specified are put on the local CPU. This 1712 guarantee is no longer true and while local CPU is still 1713 preferred work items may be put on foreign CPUs. Kernel 1714 parameter "workqueue.debug_force_rr_cpu" is added to force 1715 round-robin CPU selection to flush out usages which depend on the 1716 now broken guarantee. This config option enables the debug 1717 feature by default. When enabled, memory and cache locality will 1718 be impacted. 1719 1720config CPU_HOTPLUG_STATE_CONTROL 1721 bool "Enable CPU hotplug state control" 1722 depends on DEBUG_KERNEL 1723 depends on HOTPLUG_CPU 1724 default n 1725 help 1726 Allows to write steps between "offline" and "online" to the CPUs 1727 sysfs target file so states can be stepped granular. This is a debug 1728 option for now as the hotplug machinery cannot be stopped and 1729 restarted at arbitrary points yet. 1730 1731 Say N if your are unsure. 1732 1733config LATENCYTOP 1734 bool "Latency measuring infrastructure" 1735 depends on DEBUG_KERNEL 1736 depends on STACKTRACE_SUPPORT 1737 depends on PROC_FS 1738 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1739 select KALLSYMS 1740 select KALLSYMS_ALL 1741 select STACKTRACE 1742 select SCHEDSTATS 1743 help 1744 Enable this option if you want to use the LatencyTOP tool 1745 to find out which userspace is blocking on what kernel operations. 1746 1747config DEBUG_CGROUP_REF 1748 bool "Disable inlining of cgroup css reference count functions" 1749 depends on DEBUG_KERNEL 1750 depends on CGROUPS 1751 depends on KPROBES 1752 default n 1753 help 1754 Force cgroup css reference count functions to not be inlined so 1755 that they can be kprobed for debugging. 1756 1757source "kernel/trace/Kconfig" 1758 1759config PROVIDE_OHCI1394_DMA_INIT 1760 bool "Remote debugging over FireWire early on boot" 1761 depends on PCI && X86 1762 help 1763 If you want to debug problems which hang or crash the kernel early 1764 on boot and the crashing machine has a FireWire port, you can use 1765 this feature to remotely access the memory of the crashed machine 1766 over FireWire. This employs remote DMA as part of the OHCI1394 1767 specification which is now the standard for FireWire controllers. 1768 1769 With remote DMA, you can monitor the printk buffer remotely using 1770 firescope and access all memory below 4GB using fireproxy from gdb. 1771 Even controlling a kernel debugger is possible using remote DMA. 1772 1773 Usage: 1774 1775 If ohci1394_dma=early is used as boot parameter, it will initialize 1776 all OHCI1394 controllers which are found in the PCI config space. 1777 1778 As all changes to the FireWire bus such as enabling and disabling 1779 devices cause a bus reset and thereby disable remote DMA for all 1780 devices, be sure to have the cable plugged and FireWire enabled on 1781 the debugging host before booting the debug target for debugging. 1782 1783 This code (~1k) is freed after boot. By then, the firewire stack 1784 in charge of the OHCI-1394 controllers should be used instead. 1785 1786 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1787 1788source "samples/Kconfig" 1789 1790config ARCH_HAS_DEVMEM_IS_ALLOWED 1791 bool 1792 1793config STRICT_DEVMEM 1794 bool "Filter access to /dev/mem" 1795 depends on MMU && DEVMEM 1796 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1797 default y if PPC || X86 || ARM64 1798 help 1799 If this option is disabled, you allow userspace (root) access to all 1800 of memory, including kernel and userspace memory. Accidental 1801 access to this is obviously disastrous, but specific access can 1802 be used by people debugging the kernel. Note that with PAT support 1803 enabled, even in this case there are restrictions on /dev/mem 1804 use due to the cache aliasing requirements. 1805 1806 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1807 file only allows userspace access to PCI space and the BIOS code and 1808 data regions. This is sufficient for dosemu and X and all common 1809 users of /dev/mem. 1810 1811 If in doubt, say Y. 1812 1813config IO_STRICT_DEVMEM 1814 bool "Filter I/O access to /dev/mem" 1815 depends on STRICT_DEVMEM 1816 help 1817 If this option is disabled, you allow userspace (root) access to all 1818 io-memory regardless of whether a driver is actively using that 1819 range. Accidental access to this is obviously disastrous, but 1820 specific access can be used by people debugging kernel drivers. 1821 1822 If this option is switched on, the /dev/mem file only allows 1823 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1824 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1825 if the driver using a given range cannot be disabled. 1826 1827 If in doubt, say Y. 1828 1829menu "$(SRCARCH) Debugging" 1830 1831source "arch/$(SRCARCH)/Kconfig.debug" 1832 1833endmenu 1834 1835menu "Kernel Testing and Coverage" 1836 1837source "lib/kunit/Kconfig" 1838 1839config NOTIFIER_ERROR_INJECTION 1840 tristate "Notifier error injection" 1841 depends on DEBUG_KERNEL 1842 select DEBUG_FS 1843 help 1844 This option provides the ability to inject artificial errors to 1845 specified notifier chain callbacks. It is useful to test the error 1846 handling of notifier call chain failures. 1847 1848 Say N if unsure. 1849 1850config PM_NOTIFIER_ERROR_INJECT 1851 tristate "PM notifier error injection module" 1852 depends on PM && NOTIFIER_ERROR_INJECTION 1853 default m if PM_DEBUG 1854 help 1855 This option provides the ability to inject artificial errors to 1856 PM notifier chain callbacks. It is controlled through debugfs 1857 interface /sys/kernel/debug/notifier-error-inject/pm 1858 1859 If the notifier call chain should be failed with some events 1860 notified, write the error code to "actions/<notifier event>/error". 1861 1862 Example: Inject PM suspend error (-12 = -ENOMEM) 1863 1864 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1865 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1866 # echo mem > /sys/power/state 1867 bash: echo: write error: Cannot allocate memory 1868 1869 To compile this code as a module, choose M here: the module will 1870 be called pm-notifier-error-inject. 1871 1872 If unsure, say N. 1873 1874config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1875 tristate "OF reconfig notifier error injection module" 1876 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1877 help 1878 This option provides the ability to inject artificial errors to 1879 OF reconfig notifier chain callbacks. It is controlled 1880 through debugfs interface under 1881 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1882 1883 If the notifier call chain should be failed with some events 1884 notified, write the error code to "actions/<notifier event>/error". 1885 1886 To compile this code as a module, choose M here: the module will 1887 be called of-reconfig-notifier-error-inject. 1888 1889 If unsure, say N. 1890 1891config NETDEV_NOTIFIER_ERROR_INJECT 1892 tristate "Netdev notifier error injection module" 1893 depends on NET && NOTIFIER_ERROR_INJECTION 1894 help 1895 This option provides the ability to inject artificial errors to 1896 netdevice notifier chain callbacks. It is controlled through debugfs 1897 interface /sys/kernel/debug/notifier-error-inject/netdev 1898 1899 If the notifier call chain should be failed with some events 1900 notified, write the error code to "actions/<notifier event>/error". 1901 1902 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1903 1904 # cd /sys/kernel/debug/notifier-error-inject/netdev 1905 # echo -22 > actions/NETDEV_CHANGEMTU/error 1906 # ip link set eth0 mtu 1024 1907 RTNETLINK answers: Invalid argument 1908 1909 To compile this code as a module, choose M here: the module will 1910 be called netdev-notifier-error-inject. 1911 1912 If unsure, say N. 1913 1914config FUNCTION_ERROR_INJECTION 1915 bool "Fault-injections of functions" 1916 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1917 help 1918 Add fault injections into various functions that are annotated with 1919 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1920 value of these functions. This is useful to test error paths of code. 1921 1922 If unsure, say N 1923 1924config FAULT_INJECTION 1925 bool "Fault-injection framework" 1926 depends on DEBUG_KERNEL 1927 help 1928 Provide fault-injection framework. 1929 For more details, see Documentation/fault-injection/. 1930 1931config FAILSLAB 1932 bool "Fault-injection capability for kmalloc" 1933 depends on FAULT_INJECTION 1934 depends on SLAB || SLUB 1935 help 1936 Provide fault-injection capability for kmalloc. 1937 1938config FAIL_PAGE_ALLOC 1939 bool "Fault-injection capability for alloc_pages()" 1940 depends on FAULT_INJECTION 1941 help 1942 Provide fault-injection capability for alloc_pages(). 1943 1944config FAULT_INJECTION_USERCOPY 1945 bool "Fault injection capability for usercopy functions" 1946 depends on FAULT_INJECTION 1947 help 1948 Provides fault-injection capability to inject failures 1949 in usercopy functions (copy_from_user(), get_user(), ...). 1950 1951config FAIL_MAKE_REQUEST 1952 bool "Fault-injection capability for disk IO" 1953 depends on FAULT_INJECTION && BLOCK 1954 help 1955 Provide fault-injection capability for disk IO. 1956 1957config FAIL_IO_TIMEOUT 1958 bool "Fault-injection capability for faking disk interrupts" 1959 depends on FAULT_INJECTION && BLOCK 1960 help 1961 Provide fault-injection capability on end IO handling. This 1962 will make the block layer "forget" an interrupt as configured, 1963 thus exercising the error handling. 1964 1965 Only works with drivers that use the generic timeout handling, 1966 for others it won't do anything. 1967 1968config FAIL_FUTEX 1969 bool "Fault-injection capability for futexes" 1970 select DEBUG_FS 1971 depends on FAULT_INJECTION && FUTEX 1972 help 1973 Provide fault-injection capability for futexes. 1974 1975config FAULT_INJECTION_DEBUG_FS 1976 bool "Debugfs entries for fault-injection capabilities" 1977 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1978 help 1979 Enable configuration of fault-injection capabilities via debugfs. 1980 1981config FAIL_FUNCTION 1982 bool "Fault-injection capability for functions" 1983 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1984 help 1985 Provide function-based fault-injection capability. 1986 This will allow you to override a specific function with a return 1987 with given return value. As a result, function caller will see 1988 an error value and have to handle it. This is useful to test the 1989 error handling in various subsystems. 1990 1991config FAIL_MMC_REQUEST 1992 bool "Fault-injection capability for MMC IO" 1993 depends on FAULT_INJECTION_DEBUG_FS && MMC 1994 help 1995 Provide fault-injection capability for MMC IO. 1996 This will make the mmc core return data errors. This is 1997 useful to test the error handling in the mmc block device 1998 and to test how the mmc host driver handles retries from 1999 the block device. 2000 2001config FAIL_SUNRPC 2002 bool "Fault-injection capability for SunRPC" 2003 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2004 help 2005 Provide fault-injection capability for SunRPC and 2006 its consumers. 2007 2008config FAULT_INJECTION_STACKTRACE_FILTER 2009 bool "stacktrace filter for fault-injection capabilities" 2010 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 2011 select STACKTRACE 2012 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2013 help 2014 Provide stacktrace filter for fault-injection capabilities 2015 2016config ARCH_HAS_KCOV 2017 bool 2018 help 2019 An architecture should select this when it can successfully 2020 build and run with CONFIG_KCOV. This typically requires 2021 disabling instrumentation for some early boot code. 2022 2023config CC_HAS_SANCOV_TRACE_PC 2024 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2025 2026 2027config KCOV 2028 bool "Code coverage for fuzzing" 2029 depends on ARCH_HAS_KCOV 2030 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2031 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2032 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2033 select DEBUG_FS 2034 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2035 select OBJTOOL if HAVE_NOINSTR_HACK 2036 help 2037 KCOV exposes kernel code coverage information in a form suitable 2038 for coverage-guided fuzzing (randomized testing). 2039 2040 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2041 different machines and across reboots. If you need stable PC values, 2042 disable RANDOMIZE_BASE. 2043 2044 For more details, see Documentation/dev-tools/kcov.rst. 2045 2046config KCOV_ENABLE_COMPARISONS 2047 bool "Enable comparison operands collection by KCOV" 2048 depends on KCOV 2049 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2050 help 2051 KCOV also exposes operands of every comparison in the instrumented 2052 code along with operand sizes and PCs of the comparison instructions. 2053 These operands can be used by fuzzing engines to improve the quality 2054 of fuzzing coverage. 2055 2056config KCOV_INSTRUMENT_ALL 2057 bool "Instrument all code by default" 2058 depends on KCOV 2059 default y 2060 help 2061 If you are doing generic system call fuzzing (like e.g. syzkaller), 2062 then you will want to instrument the whole kernel and you should 2063 say y here. If you are doing more targeted fuzzing (like e.g. 2064 filesystem fuzzing with AFL) then you will want to enable coverage 2065 for more specific subsets of files, and should say n here. 2066 2067config KCOV_IRQ_AREA_SIZE 2068 hex "Size of interrupt coverage collection area in words" 2069 depends on KCOV 2070 default 0x40000 2071 help 2072 KCOV uses preallocated per-cpu areas to collect coverage from 2073 soft interrupts. This specifies the size of those areas in the 2074 number of unsigned long words. 2075 2076menuconfig RUNTIME_TESTING_MENU 2077 bool "Runtime Testing" 2078 def_bool y 2079 2080if RUNTIME_TESTING_MENU 2081 2082config LKDTM 2083 tristate "Linux Kernel Dump Test Tool Module" 2084 depends on DEBUG_FS 2085 help 2086 This module enables testing of the different dumping mechanisms by 2087 inducing system failures at predefined crash points. 2088 If you don't need it: say N 2089 Choose M here to compile this code as a module. The module will be 2090 called lkdtm. 2091 2092 Documentation on how to use the module can be found in 2093 Documentation/fault-injection/provoke-crashes.rst 2094 2095config CPUMASK_KUNIT_TEST 2096 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2097 depends on KUNIT 2098 default KUNIT_ALL_TESTS 2099 help 2100 Enable to turn on cpumask tests, running at boot or module load time. 2101 2102 For more information on KUnit and unit tests in general, please refer 2103 to the KUnit documentation in Documentation/dev-tools/kunit/. 2104 2105 If unsure, say N. 2106 2107config TEST_LIST_SORT 2108 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2109 depends on KUNIT 2110 default KUNIT_ALL_TESTS 2111 help 2112 Enable this to turn on 'list_sort()' function test. This test is 2113 executed only once during system boot (so affects only boot time), 2114 or at module load time. 2115 2116 If unsure, say N. 2117 2118config TEST_MIN_HEAP 2119 tristate "Min heap test" 2120 depends on DEBUG_KERNEL || m 2121 help 2122 Enable this to turn on min heap function tests. This test is 2123 executed only once during system boot (so affects only boot time), 2124 or at module load time. 2125 2126 If unsure, say N. 2127 2128config TEST_SORT 2129 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2130 depends on KUNIT 2131 default KUNIT_ALL_TESTS 2132 help 2133 This option enables the self-test function of 'sort()' at boot, 2134 or at module load time. 2135 2136 If unsure, say N. 2137 2138config TEST_DIV64 2139 tristate "64bit/32bit division and modulo test" 2140 depends on DEBUG_KERNEL || m 2141 help 2142 Enable this to turn on 'do_div()' function test. This test is 2143 executed only once during system boot (so affects only boot time), 2144 or at module load time. 2145 2146 If unsure, say N. 2147 2148config KPROBES_SANITY_TEST 2149 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2150 depends on DEBUG_KERNEL 2151 depends on KPROBES 2152 depends on KUNIT 2153 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2154 default KUNIT_ALL_TESTS 2155 help 2156 This option provides for testing basic kprobes functionality on 2157 boot. Samples of kprobe and kretprobe are inserted and 2158 verified for functionality. 2159 2160 Say N if you are unsure. 2161 2162config FPROBE_SANITY_TEST 2163 bool "Self test for fprobe" 2164 depends on DEBUG_KERNEL 2165 depends on FPROBE 2166 depends on KUNIT=y 2167 help 2168 This option will enable testing the fprobe when the system boot. 2169 A series of tests are made to verify that the fprobe is functioning 2170 properly. 2171 2172 Say N if you are unsure. 2173 2174config BACKTRACE_SELF_TEST 2175 tristate "Self test for the backtrace code" 2176 depends on DEBUG_KERNEL 2177 help 2178 This option provides a kernel module that can be used to test 2179 the kernel stack backtrace code. This option is not useful 2180 for distributions or general kernels, but only for kernel 2181 developers working on architecture code. 2182 2183 Note that if you want to also test saved backtraces, you will 2184 have to enable STACKTRACE as well. 2185 2186 Say N if you are unsure. 2187 2188config TEST_REF_TRACKER 2189 tristate "Self test for reference tracker" 2190 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2191 select REF_TRACKER 2192 help 2193 This option provides a kernel module performing tests 2194 using reference tracker infrastructure. 2195 2196 Say N if you are unsure. 2197 2198config RBTREE_TEST 2199 tristate "Red-Black tree test" 2200 depends on DEBUG_KERNEL 2201 help 2202 A benchmark measuring the performance of the rbtree library. 2203 Also includes rbtree invariant checks. 2204 2205config REED_SOLOMON_TEST 2206 tristate "Reed-Solomon library test" 2207 depends on DEBUG_KERNEL || m 2208 select REED_SOLOMON 2209 select REED_SOLOMON_ENC16 2210 select REED_SOLOMON_DEC16 2211 help 2212 This option enables the self-test function of rslib at boot, 2213 or at module load time. 2214 2215 If unsure, say N. 2216 2217config INTERVAL_TREE_TEST 2218 tristate "Interval tree test" 2219 depends on DEBUG_KERNEL 2220 select INTERVAL_TREE 2221 help 2222 A benchmark measuring the performance of the interval tree library 2223 2224config PERCPU_TEST 2225 tristate "Per cpu operations test" 2226 depends on m && DEBUG_KERNEL 2227 help 2228 Enable this option to build test module which validates per-cpu 2229 operations. 2230 2231 If unsure, say N. 2232 2233config ATOMIC64_SELFTEST 2234 tristate "Perform an atomic64_t self-test" 2235 help 2236 Enable this option to test the atomic64_t functions at boot or 2237 at module load time. 2238 2239 If unsure, say N. 2240 2241config ASYNC_RAID6_TEST 2242 tristate "Self test for hardware accelerated raid6 recovery" 2243 depends on ASYNC_RAID6_RECOV 2244 select ASYNC_MEMCPY 2245 help 2246 This is a one-shot self test that permutes through the 2247 recovery of all the possible two disk failure scenarios for a 2248 N-disk array. Recovery is performed with the asynchronous 2249 raid6 recovery routines, and will optionally use an offload 2250 engine if one is available. 2251 2252 If unsure, say N. 2253 2254config TEST_HEXDUMP 2255 tristate "Test functions located in the hexdump module at runtime" 2256 2257config STRING_SELFTEST 2258 tristate "Test string functions at runtime" 2259 2260config TEST_STRING_HELPERS 2261 tristate "Test functions located in the string_helpers module at runtime" 2262 2263config TEST_KSTRTOX 2264 tristate "Test kstrto*() family of functions at runtime" 2265 2266config TEST_PRINTF 2267 tristate "Test printf() family of functions at runtime" 2268 2269config TEST_SCANF 2270 tristate "Test scanf() family of functions at runtime" 2271 2272config TEST_BITMAP 2273 tristate "Test bitmap_*() family of functions at runtime" 2274 help 2275 Enable this option to test the bitmap functions at boot. 2276 2277 If unsure, say N. 2278 2279config TEST_UUID 2280 tristate "Test functions located in the uuid module at runtime" 2281 2282config TEST_XARRAY 2283 tristate "Test the XArray code at runtime" 2284 2285config TEST_MAPLE_TREE 2286 depends on DEBUG_KERNEL 2287 select DEBUG_MAPLE_TREE 2288 tristate "Test the Maple Tree code at runtime" 2289 2290config TEST_RHASHTABLE 2291 tristate "Perform selftest on resizable hash table" 2292 help 2293 Enable this option to test the rhashtable functions at boot. 2294 2295 If unsure, say N. 2296 2297config TEST_IDA 2298 tristate "Perform selftest on IDA functions" 2299 2300config TEST_PARMAN 2301 tristate "Perform selftest on priority array manager" 2302 depends on PARMAN 2303 help 2304 Enable this option to test priority array manager on boot 2305 (or module load). 2306 2307 If unsure, say N. 2308 2309config TEST_IRQ_TIMINGS 2310 bool "IRQ timings selftest" 2311 depends on IRQ_TIMINGS 2312 help 2313 Enable this option to test the irq timings code on boot. 2314 2315 If unsure, say N. 2316 2317config TEST_LKM 2318 tristate "Test module loading with 'hello world' module" 2319 depends on m 2320 help 2321 This builds the "test_module" module that emits "Hello, world" 2322 on printk when loaded. It is designed to be used for basic 2323 evaluation of the module loading subsystem (for example when 2324 validating module verification). It lacks any extra dependencies, 2325 and will not normally be loaded by the system unless explicitly 2326 requested by name. 2327 2328 If unsure, say N. 2329 2330config TEST_BITOPS 2331 tristate "Test module for compilation of bitops operations" 2332 depends on m 2333 help 2334 This builds the "test_bitops" module that is much like the 2335 TEST_LKM module except that it does a basic exercise of the 2336 set/clear_bit macros and get_count_order/long to make sure there are 2337 no compiler warnings from C=1 sparse checker or -Wextra 2338 compilations. It has no dependencies and doesn't run or load unless 2339 explicitly requested by name. for example: modprobe test_bitops. 2340 2341 If unsure, say N. 2342 2343config TEST_VMALLOC 2344 tristate "Test module for stress/performance analysis of vmalloc allocator" 2345 default n 2346 depends on MMU 2347 depends on m 2348 help 2349 This builds the "test_vmalloc" module that should be used for 2350 stress and performance analysis. So, any new change for vmalloc 2351 subsystem can be evaluated from performance and stability point 2352 of view. 2353 2354 If unsure, say N. 2355 2356config TEST_USER_COPY 2357 tristate "Test user/kernel boundary protections" 2358 depends on m 2359 help 2360 This builds the "test_user_copy" module that runs sanity checks 2361 on the copy_to/from_user infrastructure, making sure basic 2362 user/kernel boundary testing is working. If it fails to load, 2363 a regression has been detected in the user/kernel memory boundary 2364 protections. 2365 2366 If unsure, say N. 2367 2368config TEST_BPF 2369 tristate "Test BPF filter functionality" 2370 depends on m && NET 2371 help 2372 This builds the "test_bpf" module that runs various test vectors 2373 against the BPF interpreter or BPF JIT compiler depending on the 2374 current setting. This is in particular useful for BPF JIT compiler 2375 development, but also to run regression tests against changes in 2376 the interpreter code. It also enables test stubs for eBPF maps and 2377 verifier used by user space verifier testsuite. 2378 2379 If unsure, say N. 2380 2381config TEST_BLACKHOLE_DEV 2382 tristate "Test blackhole netdev functionality" 2383 depends on m && NET 2384 help 2385 This builds the "test_blackhole_dev" module that validates the 2386 data path through this blackhole netdev. 2387 2388 If unsure, say N. 2389 2390config FIND_BIT_BENCHMARK 2391 tristate "Test find_bit functions" 2392 help 2393 This builds the "test_find_bit" module that measure find_*_bit() 2394 functions performance. 2395 2396 If unsure, say N. 2397 2398config TEST_FIRMWARE 2399 tristate "Test firmware loading via userspace interface" 2400 depends on FW_LOADER 2401 help 2402 This builds the "test_firmware" module that creates a userspace 2403 interface for testing firmware loading. This can be used to 2404 control the triggering of firmware loading without needing an 2405 actual firmware-using device. The contents can be rechecked by 2406 userspace. 2407 2408 If unsure, say N. 2409 2410config TEST_SYSCTL 2411 tristate "sysctl test driver" 2412 depends on PROC_SYSCTL 2413 help 2414 This builds the "test_sysctl" module. This driver enables to test the 2415 proc sysctl interfaces available to drivers safely without affecting 2416 production knobs which might alter system functionality. 2417 2418 If unsure, say N. 2419 2420config BITFIELD_KUNIT 2421 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2422 depends on KUNIT 2423 default KUNIT_ALL_TESTS 2424 help 2425 Enable this option to test the bitfield functions at boot. 2426 2427 KUnit tests run during boot and output the results to the debug log 2428 in TAP format (http://testanything.org/). Only useful for kernel devs 2429 running the KUnit test harness, and not intended for inclusion into a 2430 production build. 2431 2432 For more information on KUnit and unit tests in general please refer 2433 to the KUnit documentation in Documentation/dev-tools/kunit/. 2434 2435 If unsure, say N. 2436 2437config HASH_KUNIT_TEST 2438 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2439 depends on KUNIT 2440 default KUNIT_ALL_TESTS 2441 help 2442 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2443 integer (<linux/hash.h>) hash functions on boot. 2444 2445 KUnit tests run during boot and output the results to the debug log 2446 in TAP format (https://testanything.org/). Only useful for kernel devs 2447 running the KUnit test harness, and not intended for inclusion into a 2448 production build. 2449 2450 For more information on KUnit and unit tests in general please refer 2451 to the KUnit documentation in Documentation/dev-tools/kunit/. 2452 2453 This is intended to help people writing architecture-specific 2454 optimized versions. If unsure, say N. 2455 2456config RESOURCE_KUNIT_TEST 2457 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2458 depends on KUNIT 2459 default KUNIT_ALL_TESTS 2460 help 2461 This builds the resource API unit test. 2462 Tests the logic of API provided by resource.c and ioport.h. 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 SYSCTL_KUNIT_TEST 2469 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2470 depends on KUNIT 2471 default KUNIT_ALL_TESTS 2472 help 2473 This builds the proc sysctl unit test, which runs on boot. 2474 Tests the API contract and implementation correctness of sysctl. 2475 For more information on KUnit and unit tests in general please refer 2476 to the KUnit documentation in Documentation/dev-tools/kunit/. 2477 2478 If unsure, say N. 2479 2480config LIST_KUNIT_TEST 2481 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2482 depends on KUNIT 2483 default KUNIT_ALL_TESTS 2484 help 2485 This builds the linked list KUnit test suite. 2486 It tests that the API and basic functionality of the list_head type 2487 and associated macros. 2488 2489 KUnit tests run during boot and output the results to the debug log 2490 in TAP format (https://testanything.org/). Only useful for kernel devs 2491 running the KUnit test harness, and not intended for inclusion into a 2492 production build. 2493 2494 For more information on KUnit and unit tests in general please refer 2495 to the KUnit documentation in Documentation/dev-tools/kunit/. 2496 2497 If unsure, say N. 2498 2499config LINEAR_RANGES_TEST 2500 tristate "KUnit test for linear_ranges" 2501 depends on KUNIT 2502 select LINEAR_RANGES 2503 help 2504 This builds the linear_ranges unit test, which runs on boot. 2505 Tests the linear_ranges logic correctness. 2506 For more information on KUnit and unit tests in general please refer 2507 to the KUnit documentation in Documentation/dev-tools/kunit/. 2508 2509 If unsure, say N. 2510 2511config CMDLINE_KUNIT_TEST 2512 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2513 depends on KUNIT 2514 default KUNIT_ALL_TESTS 2515 help 2516 This builds the cmdline API unit test. 2517 Tests the logic of API provided by cmdline.c. 2518 For more information on KUnit and unit tests in general please refer 2519 to the KUnit documentation in Documentation/dev-tools/kunit/. 2520 2521 If unsure, say N. 2522 2523config BITS_TEST 2524 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2525 depends on KUNIT 2526 default KUNIT_ALL_TESTS 2527 help 2528 This builds the bits unit test. 2529 Tests the logic of macros defined in bits.h. 2530 For more information on KUnit and unit tests in general please refer 2531 to the KUnit documentation in Documentation/dev-tools/kunit/. 2532 2533 If unsure, say N. 2534 2535config SLUB_KUNIT_TEST 2536 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2537 depends on SLUB_DEBUG && KUNIT 2538 default KUNIT_ALL_TESTS 2539 help 2540 This builds SLUB allocator unit test. 2541 Tests SLUB cache debugging functionality. 2542 For more information on KUnit and unit tests in general please refer 2543 to the KUnit documentation in Documentation/dev-tools/kunit/. 2544 2545 If unsure, say N. 2546 2547config RATIONAL_KUNIT_TEST 2548 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2549 depends on KUNIT && RATIONAL 2550 default KUNIT_ALL_TESTS 2551 help 2552 This builds the rational math unit test. 2553 For more information on KUnit and unit tests in general please refer 2554 to the KUnit documentation in Documentation/dev-tools/kunit/. 2555 2556 If unsure, say N. 2557 2558config MEMCPY_KUNIT_TEST 2559 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2560 depends on KUNIT 2561 default KUNIT_ALL_TESTS 2562 help 2563 Builds unit tests for memcpy(), memmove(), and memset() functions. 2564 For more information on KUnit and unit tests in general please refer 2565 to the KUnit documentation in Documentation/dev-tools/kunit/. 2566 2567 If unsure, say N. 2568 2569config MEMCPY_SLOW_KUNIT_TEST 2570 bool "Include exhaustive memcpy tests" 2571 depends on MEMCPY_KUNIT_TEST 2572 default y 2573 help 2574 Some memcpy tests are quite exhaustive in checking for overlaps 2575 and bit ranges. These can be very slow, so they are split out 2576 as a separate config, in case they need to be disabled. 2577 2578config IS_SIGNED_TYPE_KUNIT_TEST 2579 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2580 depends on KUNIT 2581 default KUNIT_ALL_TESTS 2582 help 2583 Builds unit tests for the is_signed_type() macro. 2584 2585 For more information on KUnit and unit tests in general please refer 2586 to the KUnit documentation in Documentation/dev-tools/kunit/. 2587 2588 If unsure, say N. 2589 2590config OVERFLOW_KUNIT_TEST 2591 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2592 depends on KUNIT 2593 default KUNIT_ALL_TESTS 2594 help 2595 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2596 related functions. 2597 2598 For more information on KUnit and unit tests in general please refer 2599 to the KUnit documentation in Documentation/dev-tools/kunit/. 2600 2601 If unsure, say N. 2602 2603config STACKINIT_KUNIT_TEST 2604 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2605 depends on KUNIT 2606 default KUNIT_ALL_TESTS 2607 help 2608 Test if the kernel is zero-initializing stack variables and 2609 padding. Coverage is controlled by compiler flags, 2610 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2611 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2612 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2613 2614config FORTIFY_KUNIT_TEST 2615 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2616 depends on KUNIT && FORTIFY_SOURCE 2617 default KUNIT_ALL_TESTS 2618 help 2619 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2620 by the str*() and mem*() family of functions. For testing runtime 2621 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2622 2623config HW_BREAKPOINT_KUNIT_TEST 2624 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2625 depends on HAVE_HW_BREAKPOINT 2626 depends on KUNIT=y 2627 default KUNIT_ALL_TESTS 2628 help 2629 Tests for hw_breakpoint constraints accounting. 2630 2631 If unsure, say N. 2632 2633config STRSCPY_KUNIT_TEST 2634 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2635 depends on KUNIT 2636 default KUNIT_ALL_TESTS 2637 2638config SIPHASH_KUNIT_TEST 2639 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2640 depends on KUNIT 2641 default KUNIT_ALL_TESTS 2642 help 2643 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2644 functions on boot (or module load). 2645 2646 This is intended to help people writing architecture-specific 2647 optimized versions. If unsure, say N. 2648 2649config TEST_UDELAY 2650 tristate "udelay test driver" 2651 help 2652 This builds the "udelay_test" module that helps to make sure 2653 that udelay() is working properly. 2654 2655 If unsure, say N. 2656 2657config TEST_STATIC_KEYS 2658 tristate "Test static keys" 2659 depends on m 2660 help 2661 Test the static key interfaces. 2662 2663 If unsure, say N. 2664 2665config TEST_DYNAMIC_DEBUG 2666 tristate "Test DYNAMIC_DEBUG" 2667 depends on DYNAMIC_DEBUG 2668 help 2669 This module registers a tracer callback to count enabled 2670 pr_debugs in a 'do_debugging' function, then alters their 2671 enablements, calls the function, and compares counts. 2672 2673 If unsure, say N. 2674 2675config TEST_KMOD 2676 tristate "kmod stress tester" 2677 depends on m 2678 depends on NETDEVICES && NET_CORE && INET # for TUN 2679 depends on BLOCK 2680 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2681 select TEST_LKM 2682 select XFS_FS 2683 select TUN 2684 select BTRFS_FS 2685 help 2686 Test the kernel's module loading mechanism: kmod. kmod implements 2687 support to load modules using the Linux kernel's usermode helper. 2688 This test provides a series of tests against kmod. 2689 2690 Although technically you can either build test_kmod as a module or 2691 into the kernel we disallow building it into the kernel since 2692 it stress tests request_module() and this will very likely cause 2693 some issues by taking over precious threads available from other 2694 module load requests, ultimately this could be fatal. 2695 2696 To run tests run: 2697 2698 tools/testing/selftests/kmod/kmod.sh --help 2699 2700 If unsure, say N. 2701 2702config TEST_DEBUG_VIRTUAL 2703 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2704 depends on DEBUG_VIRTUAL 2705 help 2706 Test the kernel's ability to detect incorrect calls to 2707 virt_to_phys() done against the non-linear part of the 2708 kernel's virtual address map. 2709 2710 If unsure, say N. 2711 2712config TEST_MEMCAT_P 2713 tristate "Test memcat_p() helper function" 2714 help 2715 Test the memcat_p() helper for correctly merging two 2716 pointer arrays together. 2717 2718 If unsure, say N. 2719 2720config TEST_LIVEPATCH 2721 tristate "Test livepatching" 2722 default n 2723 depends on DYNAMIC_DEBUG 2724 depends on LIVEPATCH 2725 depends on m 2726 help 2727 Test kernel livepatching features for correctness. The tests will 2728 load test modules that will be livepatched in various scenarios. 2729 2730 To run all the livepatching tests: 2731 2732 make -C tools/testing/selftests TARGETS=livepatch run_tests 2733 2734 Alternatively, individual tests may be invoked: 2735 2736 tools/testing/selftests/livepatch/test-callbacks.sh 2737 tools/testing/selftests/livepatch/test-livepatch.sh 2738 tools/testing/selftests/livepatch/test-shadow-vars.sh 2739 2740 If unsure, say N. 2741 2742config TEST_OBJAGG 2743 tristate "Perform selftest on object aggreration manager" 2744 default n 2745 depends on OBJAGG 2746 help 2747 Enable this option to test object aggregation manager on boot 2748 (or module load). 2749 2750config TEST_MEMINIT 2751 tristate "Test heap/page initialization" 2752 help 2753 Test if the kernel is zero-initializing heap and page allocations. 2754 This can be useful to test init_on_alloc and init_on_free features. 2755 2756 If unsure, say N. 2757 2758config TEST_HMM 2759 tristate "Test HMM (Heterogeneous Memory Management)" 2760 depends on TRANSPARENT_HUGEPAGE 2761 depends on DEVICE_PRIVATE 2762 select HMM_MIRROR 2763 select MMU_NOTIFIER 2764 help 2765 This is a pseudo device driver solely for testing HMM. 2766 Say M here if you want to build the HMM test module. 2767 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2768 2769 If unsure, say N. 2770 2771config TEST_FREE_PAGES 2772 tristate "Test freeing pages" 2773 help 2774 Test that a memory leak does not occur due to a race between 2775 freeing a block of pages and a speculative page reference. 2776 Loading this module is safe if your kernel has the bug fixed. 2777 If the bug is not fixed, it will leak gigabytes of memory and 2778 probably OOM your system. 2779 2780config TEST_FPU 2781 tristate "Test floating point operations in kernel space" 2782 depends on X86 && !KCOV_INSTRUMENT_ALL 2783 help 2784 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2785 which will trigger a sequence of floating point operations. This is used 2786 for self-testing floating point control register setting in 2787 kernel_fpu_begin(). 2788 2789 If unsure, say N. 2790 2791config TEST_CLOCKSOURCE_WATCHDOG 2792 tristate "Test clocksource watchdog in kernel space" 2793 depends on CLOCKSOURCE_WATCHDOG 2794 help 2795 Enable this option to create a kernel module that will trigger 2796 a test of the clocksource watchdog. This module may be loaded 2797 via modprobe or insmod in which case it will run upon being 2798 loaded, or it may be built in, in which case it will run 2799 shortly after boot. 2800 2801 If unsure, say N. 2802 2803endif # RUNTIME_TESTING_MENU 2804 2805config ARCH_USE_MEMTEST 2806 bool 2807 help 2808 An architecture should select this when it uses early_memtest() 2809 during boot process. 2810 2811config MEMTEST 2812 bool "Memtest" 2813 depends on ARCH_USE_MEMTEST 2814 help 2815 This option adds a kernel parameter 'memtest', which allows memtest 2816 to be set and executed. 2817 memtest=0, mean disabled; -- default 2818 memtest=1, mean do 1 test pattern; 2819 ... 2820 memtest=17, mean do 17 test patterns. 2821 If you are unsure how to answer this question, answer N. 2822 2823 2824 2825config HYPERV_TESTING 2826 bool "Microsoft Hyper-V driver testing" 2827 default n 2828 depends on HYPERV && DEBUG_FS 2829 help 2830 Select this option to enable Hyper-V vmbus testing. 2831 2832endmenu # "Kernel Testing and Coverage" 2833 2834menu "Rust hacking" 2835 2836config RUST_DEBUG_ASSERTIONS 2837 bool "Debug assertions" 2838 depends on RUST 2839 help 2840 Enables rustc's `-Cdebug-assertions` codegen option. 2841 2842 This flag lets you turn `cfg(debug_assertions)` conditional 2843 compilation on or off. This can be used to enable extra debugging 2844 code in development but not in production. For example, it controls 2845 the behavior of the standard library's `debug_assert!` macro. 2846 2847 Note that this will apply to all Rust code, including `core`. 2848 2849 If unsure, say N. 2850 2851config RUST_OVERFLOW_CHECKS 2852 bool "Overflow checks" 2853 default y 2854 depends on RUST 2855 help 2856 Enables rustc's `-Coverflow-checks` codegen option. 2857 2858 This flag allows you to control the behavior of runtime integer 2859 overflow. When overflow-checks are enabled, a Rust panic will occur 2860 on overflow. 2861 2862 Note that this will apply to all Rust code, including `core`. 2863 2864 If unsure, say Y. 2865 2866config RUST_BUILD_ASSERT_ALLOW 2867 bool "Allow unoptimized build-time assertions" 2868 depends on RUST 2869 help 2870 Controls how are `build_error!` and `build_assert!` handled during build. 2871 2872 If calls to them exist in the binary, it may indicate a violated invariant 2873 or that the optimizer failed to verify the invariant during compilation. 2874 2875 This should not happen, thus by default the build is aborted. However, 2876 as an escape hatch, you can choose Y here to ignore them during build 2877 and let the check be carried at runtime (with `panic!` being called if 2878 the check fails). 2879 2880 If unsure, say N. 2881 2882endmenu # "Rust" 2883 2884source "Documentation/Kconfig" 2885 2886endmenu # Kernel hacking 2887