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 select STACKDEPOT_ALWAYS_INIT if !DEBUG_KMEMLEAK_DEFAULT_OFF 758 help 759 Say Y here if you want to enable the memory leak 760 detector. The memory allocation/freeing is traced in a way 761 similar to the Boehm's conservative garbage collector, the 762 difference being that the orphan objects are not freed but 763 only shown in /sys/kernel/debug/kmemleak. Enabling this 764 feature will introduce an overhead to memory 765 allocations. See Documentation/dev-tools/kmemleak.rst for more 766 details. 767 768 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 769 of finding leaks due to the slab objects poisoning. 770 771 In order to access the kmemleak file, debugfs needs to be 772 mounted (usually at /sys/kernel/debug). 773 774config DEBUG_KMEMLEAK_MEM_POOL_SIZE 775 int "Kmemleak memory pool size" 776 depends on DEBUG_KMEMLEAK 777 range 200 1000000 778 default 16000 779 help 780 Kmemleak must track all the memory allocations to avoid 781 reporting false positives. Since memory may be allocated or 782 freed before kmemleak is fully initialised, use a static pool 783 of metadata objects to track such callbacks. After kmemleak is 784 fully initialised, this memory pool acts as an emergency one 785 if slab allocations fail. 786 787config DEBUG_KMEMLEAK_TEST 788 tristate "Simple test for the kernel memory leak detector" 789 depends on DEBUG_KMEMLEAK && m 790 help 791 This option enables a module that explicitly leaks memory. 792 793 If unsure, say N. 794 795config DEBUG_KMEMLEAK_DEFAULT_OFF 796 bool "Default kmemleak to off" 797 depends on DEBUG_KMEMLEAK 798 help 799 Say Y here to disable kmemleak by default. It can then be enabled 800 on the command line via kmemleak=on. 801 802config DEBUG_KMEMLEAK_AUTO_SCAN 803 bool "Enable kmemleak auto scan thread on boot up" 804 default y 805 depends on DEBUG_KMEMLEAK 806 help 807 Depending on the cpu, kmemleak scan may be cpu intensive and can 808 stall user tasks at times. This option enables/disables automatic 809 kmemleak scan at boot up. 810 811 Say N here to disable kmemleak auto scan thread to stop automatic 812 scanning. Disabling this option disables automatic reporting of 813 memory leaks. 814 815 If unsure, say Y. 816 817config DEBUG_STACK_USAGE 818 bool "Stack utilization instrumentation" 819 depends on DEBUG_KERNEL && !IA64 820 help 821 Enables the display of the minimum amount of free stack which each 822 task has ever had available in the sysrq-T and sysrq-P debug output. 823 824 This option will slow down process creation somewhat. 825 826config SCHED_STACK_END_CHECK 827 bool "Detect stack corruption on calls to schedule()" 828 depends on DEBUG_KERNEL 829 default n 830 help 831 This option checks for a stack overrun on calls to schedule(). 832 If the stack end location is found to be over written always panic as 833 the content of the corrupted region can no longer be trusted. 834 This is to ensure no erroneous behaviour occurs which could result in 835 data corruption or a sporadic crash at a later stage once the region 836 is examined. The runtime overhead introduced is minimal. 837 838config ARCH_HAS_DEBUG_VM_PGTABLE 839 bool 840 help 841 An architecture should select this when it can successfully 842 build and run DEBUG_VM_PGTABLE. 843 844config DEBUG_VM_IRQSOFF 845 def_bool DEBUG_VM && !PREEMPT_RT 846 847config DEBUG_VM 848 bool "Debug VM" 849 depends on DEBUG_KERNEL 850 help 851 Enable this to turn on extended checks in the virtual-memory system 852 that may impact performance. 853 854 If unsure, say N. 855 856config DEBUG_VM_MAPLE_TREE 857 bool "Debug VM maple trees" 858 depends on DEBUG_VM 859 select DEBUG_MAPLE_TREE 860 help 861 Enable VM maple tree debugging information and extra validations. 862 863 If unsure, say N. 864 865config DEBUG_VM_RB 866 bool "Debug VM red-black trees" 867 depends on DEBUG_VM 868 help 869 Enable VM red-black tree debugging information and extra validations. 870 871 If unsure, say N. 872 873config DEBUG_VM_PGFLAGS 874 bool "Debug page-flags operations" 875 depends on DEBUG_VM 876 help 877 Enables extra validation on page flags operations. 878 879 If unsure, say N. 880 881config DEBUG_VM_PGTABLE 882 bool "Debug arch page table for semantics compliance" 883 depends on MMU 884 depends on ARCH_HAS_DEBUG_VM_PGTABLE 885 default y if DEBUG_VM 886 help 887 This option provides a debug method which can be used to test 888 architecture page table helper functions on various platforms in 889 verifying if they comply with expected generic MM semantics. This 890 will help architecture code in making sure that any changes or 891 new additions of these helpers still conform to expected 892 semantics of the generic MM. Platforms will have to opt in for 893 this through ARCH_HAS_DEBUG_VM_PGTABLE. 894 895 If unsure, say N. 896 897config ARCH_HAS_DEBUG_VIRTUAL 898 bool 899 900config DEBUG_VIRTUAL 901 bool "Debug VM translations" 902 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 903 help 904 Enable some costly sanity checks in virtual to page code. This can 905 catch mistakes with virt_to_page() and friends. 906 907 If unsure, say N. 908 909config DEBUG_NOMMU_REGIONS 910 bool "Debug the global anon/private NOMMU mapping region tree" 911 depends on DEBUG_KERNEL && !MMU 912 help 913 This option causes the global tree of anonymous and private mapping 914 regions to be regularly checked for invalid topology. 915 916config DEBUG_MEMORY_INIT 917 bool "Debug memory initialisation" if EXPERT 918 default !EXPERT 919 help 920 Enable this for additional checks during memory initialisation. 921 The sanity checks verify aspects of the VM such as the memory model 922 and other information provided by the architecture. Verbose 923 information will be printed at KERN_DEBUG loglevel depending 924 on the mminit_loglevel= command-line option. 925 926 If unsure, say Y 927 928config MEMORY_NOTIFIER_ERROR_INJECT 929 tristate "Memory hotplug notifier error injection module" 930 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 931 help 932 This option provides the ability to inject artificial errors to 933 memory hotplug notifier chain callbacks. It is controlled through 934 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 935 936 If the notifier call chain should be failed with some events 937 notified, write the error code to "actions/<notifier event>/error". 938 939 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 940 941 # cd /sys/kernel/debug/notifier-error-inject/memory 942 # echo -12 > actions/MEM_GOING_OFFLINE/error 943 # echo offline > /sys/devices/system/memory/memoryXXX/state 944 bash: echo: write error: Cannot allocate memory 945 946 To compile this code as a module, choose M here: the module will 947 be called memory-notifier-error-inject. 948 949 If unsure, say N. 950 951config DEBUG_PER_CPU_MAPS 952 bool "Debug access to per_cpu maps" 953 depends on DEBUG_KERNEL 954 depends on SMP 955 help 956 Say Y to verify that the per_cpu map being accessed has 957 been set up. This adds a fair amount of code to kernel memory 958 and decreases performance. 959 960 Say N if unsure. 961 962config DEBUG_KMAP_LOCAL 963 bool "Debug kmap_local temporary mappings" 964 depends on DEBUG_KERNEL && KMAP_LOCAL 965 help 966 This option enables additional error checking for the kmap_local 967 infrastructure. Disable for production use. 968 969config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 970 bool 971 972config DEBUG_KMAP_LOCAL_FORCE_MAP 973 bool "Enforce kmap_local temporary mappings" 974 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 975 select KMAP_LOCAL 976 select DEBUG_KMAP_LOCAL 977 help 978 This option enforces temporary mappings through the kmap_local 979 mechanism for non-highmem pages and on non-highmem systems. 980 Disable this for production systems! 981 982config DEBUG_HIGHMEM 983 bool "Highmem debugging" 984 depends on DEBUG_KERNEL && HIGHMEM 985 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 986 select DEBUG_KMAP_LOCAL 987 help 988 This option enables additional error checking for high memory 989 systems. Disable for production systems. 990 991config HAVE_DEBUG_STACKOVERFLOW 992 bool 993 994config DEBUG_STACKOVERFLOW 995 bool "Check for stack overflows" 996 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 997 help 998 Say Y here if you want to check for overflows of kernel, IRQ 999 and exception stacks (if your architecture uses them). This 1000 option will show detailed messages if free stack space drops 1001 below a certain limit. 1002 1003 These kinds of bugs usually occur when call-chains in the 1004 kernel get too deep, especially when interrupts are 1005 involved. 1006 1007 Use this in cases where you see apparently random memory 1008 corruption, especially if it appears in 'struct thread_info' 1009 1010 If in doubt, say "N". 1011 1012source "lib/Kconfig.kasan" 1013source "lib/Kconfig.kfence" 1014source "lib/Kconfig.kmsan" 1015 1016endmenu # "Memory Debugging" 1017 1018config DEBUG_SHIRQ 1019 bool "Debug shared IRQ handlers" 1020 depends on DEBUG_KERNEL 1021 help 1022 Enable this to generate a spurious interrupt just before a shared 1023 interrupt handler is deregistered (generating one when registering 1024 is currently disabled). Drivers need to handle this correctly. Some 1025 don't and need to be caught. 1026 1027menu "Debug Oops, Lockups and Hangs" 1028 1029config PANIC_ON_OOPS 1030 bool "Panic on Oops" 1031 help 1032 Say Y here to enable the kernel to panic when it oopses. This 1033 has the same effect as setting oops=panic on the kernel command 1034 line. 1035 1036 This feature is useful to ensure that the kernel does not do 1037 anything erroneous after an oops which could result in data 1038 corruption or other issues. 1039 1040 Say N if unsure. 1041 1042config PANIC_ON_OOPS_VALUE 1043 int 1044 range 0 1 1045 default 0 if !PANIC_ON_OOPS 1046 default 1 if PANIC_ON_OOPS 1047 1048config PANIC_TIMEOUT 1049 int "panic timeout" 1050 default 0 1051 help 1052 Set the timeout value (in seconds) until a reboot occurs when 1053 the kernel panics. If n = 0, then we wait forever. A timeout 1054 value n > 0 will wait n seconds before rebooting, while a timeout 1055 value n < 0 will reboot immediately. 1056 1057config LOCKUP_DETECTOR 1058 bool 1059 1060config SOFTLOCKUP_DETECTOR 1061 bool "Detect Soft Lockups" 1062 depends on DEBUG_KERNEL && !S390 1063 select LOCKUP_DETECTOR 1064 help 1065 Say Y here to enable the kernel to act as a watchdog to detect 1066 soft lockups. 1067 1068 Softlockups are bugs that cause the kernel to loop in kernel 1069 mode for more than 20 seconds, without giving other tasks a 1070 chance to run. The current stack trace is displayed upon 1071 detection and the system will stay locked up. 1072 1073config BOOTPARAM_SOFTLOCKUP_PANIC 1074 bool "Panic (Reboot) On Soft Lockups" 1075 depends on SOFTLOCKUP_DETECTOR 1076 help 1077 Say Y here to enable the kernel to panic on "soft lockups", 1078 which are bugs that cause the kernel to loop in kernel 1079 mode for more than 20 seconds (configurable using the watchdog_thresh 1080 sysctl), without giving other tasks a chance to run. 1081 1082 The panic can be used in combination with panic_timeout, 1083 to cause the system to reboot automatically after a 1084 lockup has been detected. This feature is useful for 1085 high-availability systems that have uptime guarantees and 1086 where a lockup must be resolved ASAP. 1087 1088 Say N if unsure. 1089 1090config HARDLOCKUP_DETECTOR_PERF 1091 bool 1092 select SOFTLOCKUP_DETECTOR 1093 1094# 1095# Enables a timestamp based low pass filter to compensate for perf based 1096# hard lockup detection which runs too fast due to turbo modes. 1097# 1098config HARDLOCKUP_CHECK_TIMESTAMP 1099 bool 1100 1101# 1102# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1103# lockup detector rather than the perf based detector. 1104# 1105config HARDLOCKUP_DETECTOR 1106 bool "Detect Hard Lockups" 1107 depends on DEBUG_KERNEL && !S390 1108 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1109 select LOCKUP_DETECTOR 1110 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1111 help 1112 Say Y here to enable the kernel to act as a watchdog to detect 1113 hard lockups. 1114 1115 Hardlockups are bugs that cause the CPU to loop in kernel mode 1116 for more than 10 seconds, without letting other interrupts have a 1117 chance to run. The current stack trace is displayed upon detection 1118 and the system will stay locked up. 1119 1120config BOOTPARAM_HARDLOCKUP_PANIC 1121 bool "Panic (Reboot) On Hard Lockups" 1122 depends on HARDLOCKUP_DETECTOR 1123 help 1124 Say Y here to enable the kernel to panic on "hard lockups", 1125 which are bugs that cause the kernel to loop in kernel 1126 mode with interrupts disabled for more than 10 seconds (configurable 1127 using the watchdog_thresh sysctl). 1128 1129 Say N if unsure. 1130 1131config DETECT_HUNG_TASK 1132 bool "Detect Hung Tasks" 1133 depends on DEBUG_KERNEL 1134 default SOFTLOCKUP_DETECTOR 1135 help 1136 Say Y here to enable the kernel to detect "hung tasks", 1137 which are bugs that cause the task to be stuck in 1138 uninterruptible "D" state indefinitely. 1139 1140 When a hung task is detected, the kernel will print the 1141 current stack trace (which you should report), but the 1142 task will stay in uninterruptible state. If lockdep is 1143 enabled then all held locks will also be reported. This 1144 feature has negligible overhead. 1145 1146config DEFAULT_HUNG_TASK_TIMEOUT 1147 int "Default timeout for hung task detection (in seconds)" 1148 depends on DETECT_HUNG_TASK 1149 default 120 1150 help 1151 This option controls the default timeout (in seconds) used 1152 to determine when a task has become non-responsive and should 1153 be considered hung. 1154 1155 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1156 sysctl or by writing a value to 1157 /proc/sys/kernel/hung_task_timeout_secs. 1158 1159 A timeout of 0 disables the check. The default is two minutes. 1160 Keeping the default should be fine in most cases. 1161 1162config BOOTPARAM_HUNG_TASK_PANIC 1163 bool "Panic (Reboot) On Hung Tasks" 1164 depends on DETECT_HUNG_TASK 1165 help 1166 Say Y here to enable the kernel to panic on "hung tasks", 1167 which are bugs that cause the kernel to leave a task stuck 1168 in uninterruptible "D" state. 1169 1170 The panic can be used in combination with panic_timeout, 1171 to cause the system to reboot automatically after a 1172 hung task has been detected. This feature is useful for 1173 high-availability systems that have uptime guarantees and 1174 where a hung tasks must be resolved ASAP. 1175 1176 Say N if unsure. 1177 1178config WQ_WATCHDOG 1179 bool "Detect Workqueue Stalls" 1180 depends on DEBUG_KERNEL 1181 help 1182 Say Y here to enable stall detection on workqueues. If a 1183 worker pool doesn't make forward progress on a pending work 1184 item for over a given amount of time, 30s by default, a 1185 warning message is printed along with dump of workqueue 1186 state. This can be configured through kernel parameter 1187 "workqueue.watchdog_thresh" and its sysfs counterpart. 1188 1189config TEST_LOCKUP 1190 tristate "Test module to generate lockups" 1191 depends on m 1192 help 1193 This builds the "test_lockup" module that helps to make sure 1194 that watchdogs and lockup detectors are working properly. 1195 1196 Depending on module parameters it could emulate soft or hard 1197 lockup, "hung task", or locking arbitrary lock for a long time. 1198 Also it could generate series of lockups with cooling-down periods. 1199 1200 If unsure, say N. 1201 1202endmenu # "Debug lockups and hangs" 1203 1204menu "Scheduler Debugging" 1205 1206config SCHED_DEBUG 1207 bool "Collect scheduler debugging info" 1208 depends on DEBUG_KERNEL && PROC_FS 1209 default y 1210 help 1211 If you say Y here, the /sys/kernel/debug/sched file will be provided 1212 that can help debug the scheduler. The runtime overhead of this 1213 option is minimal. 1214 1215config SCHED_INFO 1216 bool 1217 default n 1218 1219config SCHEDSTATS 1220 bool "Collect scheduler statistics" 1221 depends on DEBUG_KERNEL && PROC_FS 1222 select SCHED_INFO 1223 help 1224 If you say Y here, additional code will be inserted into the 1225 scheduler and related routines to collect statistics about 1226 scheduler behavior and provide them in /proc/schedstat. These 1227 stats may be useful for both tuning and debugging the scheduler 1228 If you aren't debugging the scheduler or trying to tune a specific 1229 application, you can say N to avoid the very slight overhead 1230 this adds. 1231 1232endmenu 1233 1234config DEBUG_TIMEKEEPING 1235 bool "Enable extra timekeeping sanity checking" 1236 help 1237 This option will enable additional timekeeping sanity checks 1238 which may be helpful when diagnosing issues where timekeeping 1239 problems are suspected. 1240 1241 This may include checks in the timekeeping hotpaths, so this 1242 option may have a (very small) performance impact to some 1243 workloads. 1244 1245 If unsure, say N. 1246 1247config DEBUG_PREEMPT 1248 bool "Debug preemptible kernel" 1249 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1250 default y 1251 help 1252 If you say Y here then the kernel will use a debug variant of the 1253 commonly used smp_processor_id() function and will print warnings 1254 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1255 will detect preemption count underflows. 1256 1257menu "Lock Debugging (spinlocks, mutexes, etc...)" 1258 1259config LOCK_DEBUGGING_SUPPORT 1260 bool 1261 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1262 default y 1263 1264config PROVE_LOCKING 1265 bool "Lock debugging: prove locking correctness" 1266 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1267 select LOCKDEP 1268 select DEBUG_SPINLOCK 1269 select DEBUG_MUTEXES if !PREEMPT_RT 1270 select DEBUG_RT_MUTEXES if RT_MUTEXES 1271 select DEBUG_RWSEMS 1272 select DEBUG_WW_MUTEX_SLOWPATH 1273 select DEBUG_LOCK_ALLOC 1274 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1275 select TRACE_IRQFLAGS 1276 default n 1277 help 1278 This feature enables the kernel to prove that all locking 1279 that occurs in the kernel runtime is mathematically 1280 correct: that under no circumstance could an arbitrary (and 1281 not yet triggered) combination of observed locking 1282 sequences (on an arbitrary number of CPUs, running an 1283 arbitrary number of tasks and interrupt contexts) cause a 1284 deadlock. 1285 1286 In short, this feature enables the kernel to report locking 1287 related deadlocks before they actually occur. 1288 1289 The proof does not depend on how hard and complex a 1290 deadlock scenario would be to trigger: how many 1291 participant CPUs, tasks and irq-contexts would be needed 1292 for it to trigger. The proof also does not depend on 1293 timing: if a race and a resulting deadlock is possible 1294 theoretically (no matter how unlikely the race scenario 1295 is), it will be proven so and will immediately be 1296 reported by the kernel (once the event is observed that 1297 makes the deadlock theoretically possible). 1298 1299 If a deadlock is impossible (i.e. the locking rules, as 1300 observed by the kernel, are mathematically correct), the 1301 kernel reports nothing. 1302 1303 NOTE: this feature can also be enabled for rwlocks, mutexes 1304 and rwsems - in which case all dependencies between these 1305 different locking variants are observed and mapped too, and 1306 the proof of observed correctness is also maintained for an 1307 arbitrary combination of these separate locking variants. 1308 1309 For more details, see Documentation/locking/lockdep-design.rst. 1310 1311config PROVE_RAW_LOCK_NESTING 1312 bool "Enable raw_spinlock - spinlock nesting checks" 1313 depends on PROVE_LOCKING 1314 default n 1315 help 1316 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1317 that the lock nesting rules for PREEMPT_RT enabled kernels are 1318 not violated. 1319 1320 NOTE: There are known nesting problems. So if you enable this 1321 option expect lockdep splats until these problems have been fully 1322 addressed which is work in progress. This config switch allows to 1323 identify and analyze these problems. It will be removed and the 1324 check permanently enabled once the main issues have been fixed. 1325 1326 If unsure, select N. 1327 1328config LOCK_STAT 1329 bool "Lock usage statistics" 1330 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1331 select LOCKDEP 1332 select DEBUG_SPINLOCK 1333 select DEBUG_MUTEXES if !PREEMPT_RT 1334 select DEBUG_RT_MUTEXES if RT_MUTEXES 1335 select DEBUG_LOCK_ALLOC 1336 default n 1337 help 1338 This feature enables tracking lock contention points 1339 1340 For more details, see Documentation/locking/lockstat.rst 1341 1342 This also enables lock events required by "perf lock", 1343 subcommand of perf. 1344 If you want to use "perf lock", you also need to turn on 1345 CONFIG_EVENT_TRACING. 1346 1347 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1348 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1349 1350config DEBUG_RT_MUTEXES 1351 bool "RT Mutex debugging, deadlock detection" 1352 depends on DEBUG_KERNEL && RT_MUTEXES 1353 help 1354 This allows rt mutex semantics violations and rt mutex related 1355 deadlocks (lockups) to be detected and reported automatically. 1356 1357config DEBUG_SPINLOCK 1358 bool "Spinlock and rw-lock debugging: basic checks" 1359 depends on DEBUG_KERNEL 1360 select UNINLINE_SPIN_UNLOCK 1361 help 1362 Say Y here and build SMP to catch missing spinlock initialization 1363 and certain other kinds of spinlock errors commonly made. This is 1364 best used in conjunction with the NMI watchdog so that spinlock 1365 deadlocks are also debuggable. 1366 1367config DEBUG_MUTEXES 1368 bool "Mutex debugging: basic checks" 1369 depends on DEBUG_KERNEL && !PREEMPT_RT 1370 help 1371 This feature allows mutex semantics violations to be detected and 1372 reported. 1373 1374config DEBUG_WW_MUTEX_SLOWPATH 1375 bool "Wait/wound mutex debugging: Slowpath testing" 1376 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1377 select DEBUG_LOCK_ALLOC 1378 select DEBUG_SPINLOCK 1379 select DEBUG_MUTEXES if !PREEMPT_RT 1380 select DEBUG_RT_MUTEXES if PREEMPT_RT 1381 help 1382 This feature enables slowpath testing for w/w mutex users by 1383 injecting additional -EDEADLK wound/backoff cases. Together with 1384 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1385 will test all possible w/w mutex interface abuse with the 1386 exception of simply not acquiring all the required locks. 1387 Note that this feature can introduce significant overhead, so 1388 it really should not be enabled in a production or distro kernel, 1389 even a debug kernel. If you are a driver writer, enable it. If 1390 you are a distro, do not. 1391 1392config DEBUG_RWSEMS 1393 bool "RW Semaphore debugging: basic checks" 1394 depends on DEBUG_KERNEL 1395 help 1396 This debugging feature allows mismatched rw semaphore locks 1397 and unlocks to be detected and reported. 1398 1399config DEBUG_LOCK_ALLOC 1400 bool "Lock debugging: detect incorrect freeing of live locks" 1401 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1402 select DEBUG_SPINLOCK 1403 select DEBUG_MUTEXES if !PREEMPT_RT 1404 select DEBUG_RT_MUTEXES if RT_MUTEXES 1405 select LOCKDEP 1406 help 1407 This feature will check whether any held lock (spinlock, rwlock, 1408 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1409 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1410 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1411 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1412 held during task exit. 1413 1414config LOCKDEP 1415 bool 1416 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1417 select STACKTRACE 1418 select KALLSYMS 1419 select KALLSYMS_ALL 1420 1421config LOCKDEP_SMALL 1422 bool 1423 1424config LOCKDEP_BITS 1425 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1426 depends on LOCKDEP && !LOCKDEP_SMALL 1427 range 10 30 1428 default 15 1429 help 1430 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1431 1432config LOCKDEP_CHAINS_BITS 1433 int "Bitsize for MAX_LOCKDEP_CHAINS" 1434 depends on LOCKDEP && !LOCKDEP_SMALL 1435 range 10 30 1436 default 16 1437 help 1438 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1439 1440config LOCKDEP_STACK_TRACE_BITS 1441 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1442 depends on LOCKDEP && !LOCKDEP_SMALL 1443 range 10 30 1444 default 19 1445 help 1446 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1447 1448config LOCKDEP_STACK_TRACE_HASH_BITS 1449 int "Bitsize for STACK_TRACE_HASH_SIZE" 1450 depends on LOCKDEP && !LOCKDEP_SMALL 1451 range 10 30 1452 default 14 1453 help 1454 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1455 1456config LOCKDEP_CIRCULAR_QUEUE_BITS 1457 int "Bitsize for elements in circular_queue struct" 1458 depends on LOCKDEP 1459 range 10 30 1460 default 12 1461 help 1462 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1463 1464config DEBUG_LOCKDEP 1465 bool "Lock dependency engine debugging" 1466 depends on DEBUG_KERNEL && LOCKDEP 1467 select DEBUG_IRQFLAGS 1468 help 1469 If you say Y here, the lock dependency engine will do 1470 additional runtime checks to debug itself, at the price 1471 of more runtime overhead. 1472 1473config DEBUG_ATOMIC_SLEEP 1474 bool "Sleep inside atomic section checking" 1475 select PREEMPT_COUNT 1476 depends on DEBUG_KERNEL 1477 depends on !ARCH_NO_PREEMPT 1478 help 1479 If you say Y here, various routines which may sleep will become very 1480 noisy if they are called inside atomic sections: when a spinlock is 1481 held, inside an rcu read side critical section, inside preempt disabled 1482 sections, inside an interrupt, etc... 1483 1484config DEBUG_LOCKING_API_SELFTESTS 1485 bool "Locking API boot-time self-tests" 1486 depends on DEBUG_KERNEL 1487 help 1488 Say Y here if you want the kernel to run a short self-test during 1489 bootup. The self-test checks whether common types of locking bugs 1490 are detected by debugging mechanisms or not. (if you disable 1491 lock debugging then those bugs won't be detected of course.) 1492 The following locking APIs are covered: spinlocks, rwlocks, 1493 mutexes and rwsems. 1494 1495config LOCK_TORTURE_TEST 1496 tristate "torture tests for locking" 1497 depends on DEBUG_KERNEL 1498 select TORTURE_TEST 1499 help 1500 This option provides a kernel module that runs torture tests 1501 on kernel locking primitives. The kernel module may be built 1502 after the fact on the running kernel to be tested, if desired. 1503 1504 Say Y here if you want kernel locking-primitive torture tests 1505 to be built into the kernel. 1506 Say M if you want these torture tests to build as a module. 1507 Say N if you are unsure. 1508 1509config WW_MUTEX_SELFTEST 1510 tristate "Wait/wound mutex selftests" 1511 help 1512 This option provides a kernel module that runs tests on the 1513 on the struct ww_mutex locking API. 1514 1515 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1516 with this test harness. 1517 1518 Say M if you want these self tests to build as a module. 1519 Say N if you are unsure. 1520 1521config SCF_TORTURE_TEST 1522 tristate "torture tests for smp_call_function*()" 1523 depends on DEBUG_KERNEL 1524 select TORTURE_TEST 1525 help 1526 This option provides a kernel module that runs torture tests 1527 on the smp_call_function() family of primitives. The kernel 1528 module may be built after the fact on the running kernel to 1529 be tested, if desired. 1530 1531config CSD_LOCK_WAIT_DEBUG 1532 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1533 depends on DEBUG_KERNEL 1534 depends on 64BIT 1535 default n 1536 help 1537 This option enables debug prints when CPUs are slow to respond 1538 to the smp_call_function*() IPI wrappers. These debug prints 1539 include the IPI handler function currently executing (if any) 1540 and relevant stack traces. 1541 1542endmenu # lock debugging 1543 1544config TRACE_IRQFLAGS 1545 depends on TRACE_IRQFLAGS_SUPPORT 1546 bool 1547 help 1548 Enables hooks to interrupt enabling and disabling for 1549 either tracing or lock debugging. 1550 1551config TRACE_IRQFLAGS_NMI 1552 def_bool y 1553 depends on TRACE_IRQFLAGS 1554 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1555 1556config DEBUG_IRQFLAGS 1557 bool "Debug IRQ flag manipulation" 1558 help 1559 Enables checks for potentially unsafe enabling or disabling of 1560 interrupts, such as calling raw_local_irq_restore() when interrupts 1561 are enabled. 1562 1563config STACKTRACE 1564 bool "Stack backtrace support" 1565 depends on STACKTRACE_SUPPORT 1566 help 1567 This option causes the kernel to create a /proc/pid/stack for 1568 every process, showing its current stack trace. 1569 It is also used by various kernel debugging features that require 1570 stack trace generation. 1571 1572config WARN_ALL_UNSEEDED_RANDOM 1573 bool "Warn for all uses of unseeded randomness" 1574 default n 1575 help 1576 Some parts of the kernel contain bugs relating to their use of 1577 cryptographically secure random numbers before it's actually possible 1578 to generate those numbers securely. This setting ensures that these 1579 flaws don't go unnoticed, by enabling a message, should this ever 1580 occur. This will allow people with obscure setups to know when things 1581 are going wrong, so that they might contact developers about fixing 1582 it. 1583 1584 Unfortunately, on some models of some architectures getting 1585 a fully seeded CRNG is extremely difficult, and so this can 1586 result in dmesg getting spammed for a surprisingly long 1587 time. This is really bad from a security perspective, and 1588 so architecture maintainers really need to do what they can 1589 to get the CRNG seeded sooner after the system is booted. 1590 However, since users cannot do anything actionable to 1591 address this, by default this option is disabled. 1592 1593 Say Y here if you want to receive warnings for all uses of 1594 unseeded randomness. This will be of use primarily for 1595 those developers interested in improving the security of 1596 Linux kernels running on their architecture (or 1597 subarchitecture). 1598 1599config DEBUG_KOBJECT 1600 bool "kobject debugging" 1601 depends on DEBUG_KERNEL 1602 help 1603 If you say Y here, some extra kobject debugging messages will be sent 1604 to the syslog. 1605 1606config DEBUG_KOBJECT_RELEASE 1607 bool "kobject release debugging" 1608 depends on DEBUG_OBJECTS_TIMERS 1609 help 1610 kobjects are reference counted objects. This means that their 1611 last reference count put is not predictable, and the kobject can 1612 live on past the point at which a driver decides to drop its 1613 initial reference to the kobject gained on allocation. An 1614 example of this would be a struct device which has just been 1615 unregistered. 1616 1617 However, some buggy drivers assume that after such an operation, 1618 the memory backing the kobject can be immediately freed. This 1619 goes completely against the principles of a refcounted object. 1620 1621 If you say Y here, the kernel will delay the release of kobjects 1622 on the last reference count to improve the visibility of this 1623 kind of kobject release bug. 1624 1625config HAVE_DEBUG_BUGVERBOSE 1626 bool 1627 1628menu "Debug kernel data structures" 1629 1630config DEBUG_LIST 1631 bool "Debug linked list manipulation" 1632 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1633 help 1634 Enable this to turn on extended checks in the linked-list 1635 walking routines. 1636 1637 If unsure, say N. 1638 1639config DEBUG_PLIST 1640 bool "Debug priority linked list manipulation" 1641 depends on DEBUG_KERNEL 1642 help 1643 Enable this to turn on extended checks in the priority-ordered 1644 linked-list (plist) walking routines. This checks the entire 1645 list multiple times during each manipulation. 1646 1647 If unsure, say N. 1648 1649config DEBUG_SG 1650 bool "Debug SG table operations" 1651 depends on DEBUG_KERNEL 1652 help 1653 Enable this to turn on checks on scatter-gather tables. This can 1654 help find problems with drivers that do not properly initialize 1655 their sg tables. 1656 1657 If unsure, say N. 1658 1659config DEBUG_NOTIFIERS 1660 bool "Debug notifier call chains" 1661 depends on DEBUG_KERNEL 1662 help 1663 Enable this to turn on sanity checking for notifier call chains. 1664 This is most useful for kernel developers to make sure that 1665 modules properly unregister themselves from notifier chains. 1666 This is a relatively cheap check but if you care about maximum 1667 performance, say N. 1668 1669config BUG_ON_DATA_CORRUPTION 1670 bool "Trigger a BUG when data corruption is detected" 1671 select DEBUG_LIST 1672 help 1673 Select this option if the kernel should BUG when it encounters 1674 data corruption in kernel memory structures when they get checked 1675 for validity. 1676 1677 If unsure, say N. 1678 1679config DEBUG_MAPLE_TREE 1680 bool "Debug maple trees" 1681 depends on DEBUG_KERNEL 1682 help 1683 Enable maple tree debugging information and extra validations. 1684 1685 If unsure, say N. 1686 1687endmenu 1688 1689config DEBUG_CREDENTIALS 1690 bool "Debug credential management" 1691 depends on DEBUG_KERNEL 1692 help 1693 Enable this to turn on some debug checking for credential 1694 management. The additional code keeps track of the number of 1695 pointers from task_structs to any given cred struct, and checks to 1696 see that this number never exceeds the usage count of the cred 1697 struct. 1698 1699 Furthermore, if SELinux is enabled, this also checks that the 1700 security pointer in the cred struct is never seen to be invalid. 1701 1702 If unsure, say N. 1703 1704source "kernel/rcu/Kconfig.debug" 1705 1706config DEBUG_WQ_FORCE_RR_CPU 1707 bool "Force round-robin CPU selection for unbound work items" 1708 depends on DEBUG_KERNEL 1709 default n 1710 help 1711 Workqueue used to implicitly guarantee that work items queued 1712 without explicit CPU specified are put on the local CPU. This 1713 guarantee is no longer true and while local CPU is still 1714 preferred work items may be put on foreign CPUs. Kernel 1715 parameter "workqueue.debug_force_rr_cpu" is added to force 1716 round-robin CPU selection to flush out usages which depend on the 1717 now broken guarantee. This config option enables the debug 1718 feature by default. When enabled, memory and cache locality will 1719 be impacted. 1720 1721config CPU_HOTPLUG_STATE_CONTROL 1722 bool "Enable CPU hotplug state control" 1723 depends on DEBUG_KERNEL 1724 depends on HOTPLUG_CPU 1725 default n 1726 help 1727 Allows to write steps between "offline" and "online" to the CPUs 1728 sysfs target file so states can be stepped granular. This is a debug 1729 option for now as the hotplug machinery cannot be stopped and 1730 restarted at arbitrary points yet. 1731 1732 Say N if your are unsure. 1733 1734config LATENCYTOP 1735 bool "Latency measuring infrastructure" 1736 depends on DEBUG_KERNEL 1737 depends on STACKTRACE_SUPPORT 1738 depends on PROC_FS 1739 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1740 select KALLSYMS 1741 select KALLSYMS_ALL 1742 select STACKTRACE 1743 select SCHEDSTATS 1744 help 1745 Enable this option if you want to use the LatencyTOP tool 1746 to find out which userspace is blocking on what kernel operations. 1747 1748config DEBUG_CGROUP_REF 1749 bool "Disable inlining of cgroup css reference count functions" 1750 depends on DEBUG_KERNEL 1751 depends on CGROUPS 1752 depends on KPROBES 1753 default n 1754 help 1755 Force cgroup css reference count functions to not be inlined so 1756 that they can be kprobed for debugging. 1757 1758source "kernel/trace/Kconfig" 1759 1760config PROVIDE_OHCI1394_DMA_INIT 1761 bool "Remote debugging over FireWire early on boot" 1762 depends on PCI && X86 1763 help 1764 If you want to debug problems which hang or crash the kernel early 1765 on boot and the crashing machine has a FireWire port, you can use 1766 this feature to remotely access the memory of the crashed machine 1767 over FireWire. This employs remote DMA as part of the OHCI1394 1768 specification which is now the standard for FireWire controllers. 1769 1770 With remote DMA, you can monitor the printk buffer remotely using 1771 firescope and access all memory below 4GB using fireproxy from gdb. 1772 Even controlling a kernel debugger is possible using remote DMA. 1773 1774 Usage: 1775 1776 If ohci1394_dma=early is used as boot parameter, it will initialize 1777 all OHCI1394 controllers which are found in the PCI config space. 1778 1779 As all changes to the FireWire bus such as enabling and disabling 1780 devices cause a bus reset and thereby disable remote DMA for all 1781 devices, be sure to have the cable plugged and FireWire enabled on 1782 the debugging host before booting the debug target for debugging. 1783 1784 This code (~1k) is freed after boot. By then, the firewire stack 1785 in charge of the OHCI-1394 controllers should be used instead. 1786 1787 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1788 1789source "samples/Kconfig" 1790 1791config ARCH_HAS_DEVMEM_IS_ALLOWED 1792 bool 1793 1794config STRICT_DEVMEM 1795 bool "Filter access to /dev/mem" 1796 depends on MMU && DEVMEM 1797 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1798 default y if PPC || X86 || ARM64 1799 help 1800 If this option is disabled, you allow userspace (root) access to all 1801 of memory, including kernel and userspace memory. Accidental 1802 access to this is obviously disastrous, but specific access can 1803 be used by people debugging the kernel. Note that with PAT support 1804 enabled, even in this case there are restrictions on /dev/mem 1805 use due to the cache aliasing requirements. 1806 1807 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1808 file only allows userspace access to PCI space and the BIOS code and 1809 data regions. This is sufficient for dosemu and X and all common 1810 users of /dev/mem. 1811 1812 If in doubt, say Y. 1813 1814config IO_STRICT_DEVMEM 1815 bool "Filter I/O access to /dev/mem" 1816 depends on STRICT_DEVMEM 1817 help 1818 If this option is disabled, you allow userspace (root) access to all 1819 io-memory regardless of whether a driver is actively using that 1820 range. Accidental access to this is obviously disastrous, but 1821 specific access can be used by people debugging kernel drivers. 1822 1823 If this option is switched on, the /dev/mem file only allows 1824 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1825 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1826 if the driver using a given range cannot be disabled. 1827 1828 If in doubt, say Y. 1829 1830menu "$(SRCARCH) Debugging" 1831 1832source "arch/$(SRCARCH)/Kconfig.debug" 1833 1834endmenu 1835 1836menu "Kernel Testing and Coverage" 1837 1838source "lib/kunit/Kconfig" 1839 1840config NOTIFIER_ERROR_INJECTION 1841 tristate "Notifier error injection" 1842 depends on DEBUG_KERNEL 1843 select DEBUG_FS 1844 help 1845 This option provides the ability to inject artificial errors to 1846 specified notifier chain callbacks. It is useful to test the error 1847 handling of notifier call chain failures. 1848 1849 Say N if unsure. 1850 1851config PM_NOTIFIER_ERROR_INJECT 1852 tristate "PM notifier error injection module" 1853 depends on PM && NOTIFIER_ERROR_INJECTION 1854 default m if PM_DEBUG 1855 help 1856 This option provides the ability to inject artificial errors to 1857 PM notifier chain callbacks. It is controlled through debugfs 1858 interface /sys/kernel/debug/notifier-error-inject/pm 1859 1860 If the notifier call chain should be failed with some events 1861 notified, write the error code to "actions/<notifier event>/error". 1862 1863 Example: Inject PM suspend error (-12 = -ENOMEM) 1864 1865 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1866 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1867 # echo mem > /sys/power/state 1868 bash: echo: write error: Cannot allocate memory 1869 1870 To compile this code as a module, choose M here: the module will 1871 be called pm-notifier-error-inject. 1872 1873 If unsure, say N. 1874 1875config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1876 tristate "OF reconfig notifier error injection module" 1877 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1878 help 1879 This option provides the ability to inject artificial errors to 1880 OF reconfig notifier chain callbacks. It is controlled 1881 through debugfs interface under 1882 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1883 1884 If the notifier call chain should be failed with some events 1885 notified, write the error code to "actions/<notifier event>/error". 1886 1887 To compile this code as a module, choose M here: the module will 1888 be called of-reconfig-notifier-error-inject. 1889 1890 If unsure, say N. 1891 1892config NETDEV_NOTIFIER_ERROR_INJECT 1893 tristate "Netdev notifier error injection module" 1894 depends on NET && NOTIFIER_ERROR_INJECTION 1895 help 1896 This option provides the ability to inject artificial errors to 1897 netdevice notifier chain callbacks. It is controlled through debugfs 1898 interface /sys/kernel/debug/notifier-error-inject/netdev 1899 1900 If the notifier call chain should be failed with some events 1901 notified, write the error code to "actions/<notifier event>/error". 1902 1903 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1904 1905 # cd /sys/kernel/debug/notifier-error-inject/netdev 1906 # echo -22 > actions/NETDEV_CHANGEMTU/error 1907 # ip link set eth0 mtu 1024 1908 RTNETLINK answers: Invalid argument 1909 1910 To compile this code as a module, choose M here: the module will 1911 be called netdev-notifier-error-inject. 1912 1913 If unsure, say N. 1914 1915config FUNCTION_ERROR_INJECTION 1916 bool "Fault-injections of functions" 1917 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1918 help 1919 Add fault injections into various functions that are annotated with 1920 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1921 value of theses functions. This is useful to test error paths of code. 1922 1923 If unsure, say N 1924 1925config FAULT_INJECTION 1926 bool "Fault-injection framework" 1927 depends on DEBUG_KERNEL 1928 help 1929 Provide fault-injection framework. 1930 For more details, see Documentation/fault-injection/. 1931 1932config FAILSLAB 1933 bool "Fault-injection capability for kmalloc" 1934 depends on FAULT_INJECTION 1935 depends on SLAB || SLUB 1936 help 1937 Provide fault-injection capability for kmalloc. 1938 1939config FAIL_PAGE_ALLOC 1940 bool "Fault-injection capability for alloc_pages()" 1941 depends on FAULT_INJECTION 1942 help 1943 Provide fault-injection capability for alloc_pages(). 1944 1945config FAULT_INJECTION_USERCOPY 1946 bool "Fault injection capability for usercopy functions" 1947 depends on FAULT_INJECTION 1948 help 1949 Provides fault-injection capability to inject failures 1950 in usercopy functions (copy_from_user(), get_user(), ...). 1951 1952config FAIL_MAKE_REQUEST 1953 bool "Fault-injection capability for disk IO" 1954 depends on FAULT_INJECTION && BLOCK 1955 help 1956 Provide fault-injection capability for disk IO. 1957 1958config FAIL_IO_TIMEOUT 1959 bool "Fault-injection capability for faking disk interrupts" 1960 depends on FAULT_INJECTION && BLOCK 1961 help 1962 Provide fault-injection capability on end IO handling. This 1963 will make the block layer "forget" an interrupt as configured, 1964 thus exercising the error handling. 1965 1966 Only works with drivers that use the generic timeout handling, 1967 for others it won't do anything. 1968 1969config FAIL_FUTEX 1970 bool "Fault-injection capability for futexes" 1971 select DEBUG_FS 1972 depends on FAULT_INJECTION && FUTEX 1973 help 1974 Provide fault-injection capability for futexes. 1975 1976config FAULT_INJECTION_DEBUG_FS 1977 bool "Debugfs entries for fault-injection capabilities" 1978 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1979 help 1980 Enable configuration of fault-injection capabilities via debugfs. 1981 1982config FAIL_FUNCTION 1983 bool "Fault-injection capability for functions" 1984 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1985 help 1986 Provide function-based fault-injection capability. 1987 This will allow you to override a specific function with a return 1988 with given return value. As a result, function caller will see 1989 an error value and have to handle it. This is useful to test the 1990 error handling in various subsystems. 1991 1992config FAIL_MMC_REQUEST 1993 bool "Fault-injection capability for MMC IO" 1994 depends on FAULT_INJECTION_DEBUG_FS && MMC 1995 help 1996 Provide fault-injection capability for MMC IO. 1997 This will make the mmc core return data errors. This is 1998 useful to test the error handling in the mmc block device 1999 and to test how the mmc host driver handles retries from 2000 the block device. 2001 2002config FAIL_SUNRPC 2003 bool "Fault-injection capability for SunRPC" 2004 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 2005 help 2006 Provide fault-injection capability for SunRPC and 2007 its consumers. 2008 2009config FAULT_INJECTION_STACKTRACE_FILTER 2010 bool "stacktrace filter for fault-injection capabilities" 2011 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 2012 select STACKTRACE 2013 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 2014 help 2015 Provide stacktrace filter for fault-injection capabilities 2016 2017config ARCH_HAS_KCOV 2018 bool 2019 help 2020 An architecture should select this when it can successfully 2021 build and run with CONFIG_KCOV. This typically requires 2022 disabling instrumentation for some early boot code. 2023 2024config CC_HAS_SANCOV_TRACE_PC 2025 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2026 2027 2028config KCOV 2029 bool "Code coverage for fuzzing" 2030 depends on ARCH_HAS_KCOV 2031 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2032 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2033 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2034 select DEBUG_FS 2035 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2036 select OBJTOOL if HAVE_NOINSTR_HACK 2037 help 2038 KCOV exposes kernel code coverage information in a form suitable 2039 for coverage-guided fuzzing (randomized testing). 2040 2041 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2042 different machines and across reboots. If you need stable PC values, 2043 disable RANDOMIZE_BASE. 2044 2045 For more details, see Documentation/dev-tools/kcov.rst. 2046 2047config KCOV_ENABLE_COMPARISONS 2048 bool "Enable comparison operands collection by KCOV" 2049 depends on KCOV 2050 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2051 help 2052 KCOV also exposes operands of every comparison in the instrumented 2053 code along with operand sizes and PCs of the comparison instructions. 2054 These operands can be used by fuzzing engines to improve the quality 2055 of fuzzing coverage. 2056 2057config KCOV_INSTRUMENT_ALL 2058 bool "Instrument all code by default" 2059 depends on KCOV 2060 default y 2061 help 2062 If you are doing generic system call fuzzing (like e.g. syzkaller), 2063 then you will want to instrument the whole kernel and you should 2064 say y here. If you are doing more targeted fuzzing (like e.g. 2065 filesystem fuzzing with AFL) then you will want to enable coverage 2066 for more specific subsets of files, and should say n here. 2067 2068config KCOV_IRQ_AREA_SIZE 2069 hex "Size of interrupt coverage collection area in words" 2070 depends on KCOV 2071 default 0x40000 2072 help 2073 KCOV uses preallocated per-cpu areas to collect coverage from 2074 soft interrupts. This specifies the size of those areas in the 2075 number of unsigned long words. 2076 2077menuconfig RUNTIME_TESTING_MENU 2078 bool "Runtime Testing" 2079 def_bool y 2080 2081if RUNTIME_TESTING_MENU 2082 2083config LKDTM 2084 tristate "Linux Kernel Dump Test Tool Module" 2085 depends on DEBUG_FS 2086 help 2087 This module enables testing of the different dumping mechanisms by 2088 inducing system failures at predefined crash points. 2089 If you don't need it: say N 2090 Choose M here to compile this code as a module. The module will be 2091 called lkdtm. 2092 2093 Documentation on how to use the module can be found in 2094 Documentation/fault-injection/provoke-crashes.rst 2095 2096config CPUMASK_KUNIT_TEST 2097 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2098 depends on KUNIT 2099 default KUNIT_ALL_TESTS 2100 help 2101 Enable to turn on cpumask tests, running at boot or module load time. 2102 2103 For more information on KUnit and unit tests in general, please refer 2104 to the KUnit documentation in Documentation/dev-tools/kunit/. 2105 2106 If unsure, say N. 2107 2108config TEST_LIST_SORT 2109 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2110 depends on KUNIT 2111 default KUNIT_ALL_TESTS 2112 help 2113 Enable this to turn on 'list_sort()' function test. This test is 2114 executed only once during system boot (so affects only boot time), 2115 or at module load time. 2116 2117 If unsure, say N. 2118 2119config TEST_MIN_HEAP 2120 tristate "Min heap test" 2121 depends on DEBUG_KERNEL || m 2122 help 2123 Enable this to turn on min heap function tests. This test is 2124 executed only once during system boot (so affects only boot time), 2125 or at module load time. 2126 2127 If unsure, say N. 2128 2129config TEST_SORT 2130 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2131 depends on KUNIT 2132 default KUNIT_ALL_TESTS 2133 help 2134 This option enables the self-test function of 'sort()' at boot, 2135 or at module load time. 2136 2137 If unsure, say N. 2138 2139config TEST_DIV64 2140 tristate "64bit/32bit division and modulo test" 2141 depends on DEBUG_KERNEL || m 2142 help 2143 Enable this to turn on 'do_div()' function test. This test is 2144 executed only once during system boot (so affects only boot time), 2145 or at module load time. 2146 2147 If unsure, say N. 2148 2149config KPROBES_SANITY_TEST 2150 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2151 depends on DEBUG_KERNEL 2152 depends on KPROBES 2153 depends on KUNIT 2154 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2155 default KUNIT_ALL_TESTS 2156 help 2157 This option provides for testing basic kprobes functionality on 2158 boot. Samples of kprobe and kretprobe are inserted and 2159 verified for functionality. 2160 2161 Say N if you are unsure. 2162 2163config FPROBE_SANITY_TEST 2164 bool "Self test for fprobe" 2165 depends on DEBUG_KERNEL 2166 depends on FPROBE 2167 depends on KUNIT=y 2168 help 2169 This option will enable testing the fprobe when the system boot. 2170 A series of tests are made to verify that the fprobe is functioning 2171 properly. 2172 2173 Say N if you are unsure. 2174 2175config BACKTRACE_SELF_TEST 2176 tristate "Self test for the backtrace code" 2177 depends on DEBUG_KERNEL 2178 help 2179 This option provides a kernel module that can be used to test 2180 the kernel stack backtrace code. This option is not useful 2181 for distributions or general kernels, but only for kernel 2182 developers working on architecture code. 2183 2184 Note that if you want to also test saved backtraces, you will 2185 have to enable STACKTRACE as well. 2186 2187 Say N if you are unsure. 2188 2189config TEST_REF_TRACKER 2190 tristate "Self test for reference tracker" 2191 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2192 select REF_TRACKER 2193 help 2194 This option provides a kernel module performing tests 2195 using reference tracker infrastructure. 2196 2197 Say N if you are unsure. 2198 2199config RBTREE_TEST 2200 tristate "Red-Black tree test" 2201 depends on DEBUG_KERNEL 2202 help 2203 A benchmark measuring the performance of the rbtree library. 2204 Also includes rbtree invariant checks. 2205 2206config REED_SOLOMON_TEST 2207 tristate "Reed-Solomon library test" 2208 depends on DEBUG_KERNEL || m 2209 select REED_SOLOMON 2210 select REED_SOLOMON_ENC16 2211 select REED_SOLOMON_DEC16 2212 help 2213 This option enables the self-test function of rslib at boot, 2214 or at module load time. 2215 2216 If unsure, say N. 2217 2218config INTERVAL_TREE_TEST 2219 tristate "Interval tree test" 2220 depends on DEBUG_KERNEL 2221 select INTERVAL_TREE 2222 help 2223 A benchmark measuring the performance of the interval tree library 2224 2225config PERCPU_TEST 2226 tristate "Per cpu operations test" 2227 depends on m && DEBUG_KERNEL 2228 help 2229 Enable this option to build test module which validates per-cpu 2230 operations. 2231 2232 If unsure, say N. 2233 2234config ATOMIC64_SELFTEST 2235 tristate "Perform an atomic64_t self-test" 2236 help 2237 Enable this option to test the atomic64_t functions at boot or 2238 at module load time. 2239 2240 If unsure, say N. 2241 2242config ASYNC_RAID6_TEST 2243 tristate "Self test for hardware accelerated raid6 recovery" 2244 depends on ASYNC_RAID6_RECOV 2245 select ASYNC_MEMCPY 2246 help 2247 This is a one-shot self test that permutes through the 2248 recovery of all the possible two disk failure scenarios for a 2249 N-disk array. Recovery is performed with the asynchronous 2250 raid6 recovery routines, and will optionally use an offload 2251 engine if one is available. 2252 2253 If unsure, say N. 2254 2255config TEST_HEXDUMP 2256 tristate "Test functions located in the hexdump module at runtime" 2257 2258config STRING_SELFTEST 2259 tristate "Test string functions at runtime" 2260 2261config TEST_STRING_HELPERS 2262 tristate "Test functions located in the string_helpers module at runtime" 2263 2264config TEST_KSTRTOX 2265 tristate "Test kstrto*() family of functions at runtime" 2266 2267config TEST_PRINTF 2268 tristate "Test printf() family of functions at runtime" 2269 2270config TEST_SCANF 2271 tristate "Test scanf() family of functions at runtime" 2272 2273config TEST_BITMAP 2274 tristate "Test bitmap_*() family of functions at runtime" 2275 help 2276 Enable this option to test the bitmap functions at boot. 2277 2278 If unsure, say N. 2279 2280config TEST_UUID 2281 tristate "Test functions located in the uuid module at runtime" 2282 2283config TEST_XARRAY 2284 tristate "Test the XArray code at runtime" 2285 2286config TEST_MAPLE_TREE 2287 depends on DEBUG_KERNEL 2288 select DEBUG_MAPLE_TREE 2289 tristate "Test the Maple Tree code at runtime" 2290 2291config TEST_RHASHTABLE 2292 tristate "Perform selftest on resizable hash table" 2293 help 2294 Enable this option to test the rhashtable functions at boot. 2295 2296 If unsure, say N. 2297 2298config TEST_IDA 2299 tristate "Perform selftest on IDA functions" 2300 2301config TEST_PARMAN 2302 tristate "Perform selftest on priority array manager" 2303 depends on PARMAN 2304 help 2305 Enable this option to test priority array manager on boot 2306 (or module load). 2307 2308 If unsure, say N. 2309 2310config TEST_IRQ_TIMINGS 2311 bool "IRQ timings selftest" 2312 depends on IRQ_TIMINGS 2313 help 2314 Enable this option to test the irq timings code on boot. 2315 2316 If unsure, say N. 2317 2318config TEST_LKM 2319 tristate "Test module loading with 'hello world' module" 2320 depends on m 2321 help 2322 This builds the "test_module" module that emits "Hello, world" 2323 on printk when loaded. It is designed to be used for basic 2324 evaluation of the module loading subsystem (for example when 2325 validating module verification). It lacks any extra dependencies, 2326 and will not normally be loaded by the system unless explicitly 2327 requested by name. 2328 2329 If unsure, say N. 2330 2331config TEST_BITOPS 2332 tristate "Test module for compilation of bitops operations" 2333 depends on m 2334 help 2335 This builds the "test_bitops" module that is much like the 2336 TEST_LKM module except that it does a basic exercise of the 2337 set/clear_bit macros and get_count_order/long to make sure there are 2338 no compiler warnings from C=1 sparse checker or -Wextra 2339 compilations. It has no dependencies and doesn't run or load unless 2340 explicitly requested by name. for example: modprobe test_bitops. 2341 2342 If unsure, say N. 2343 2344config TEST_VMALLOC 2345 tristate "Test module for stress/performance analysis of vmalloc allocator" 2346 default n 2347 depends on MMU 2348 depends on m 2349 help 2350 This builds the "test_vmalloc" module that should be used for 2351 stress and performance analysis. So, any new change for vmalloc 2352 subsystem can be evaluated from performance and stability point 2353 of view. 2354 2355 If unsure, say N. 2356 2357config TEST_USER_COPY 2358 tristate "Test user/kernel boundary protections" 2359 depends on m 2360 help 2361 This builds the "test_user_copy" module that runs sanity checks 2362 on the copy_to/from_user infrastructure, making sure basic 2363 user/kernel boundary testing is working. If it fails to load, 2364 a regression has been detected in the user/kernel memory boundary 2365 protections. 2366 2367 If unsure, say N. 2368 2369config TEST_BPF 2370 tristate "Test BPF filter functionality" 2371 depends on m && NET 2372 help 2373 This builds the "test_bpf" module that runs various test vectors 2374 against the BPF interpreter or BPF JIT compiler depending on the 2375 current setting. This is in particular useful for BPF JIT compiler 2376 development, but also to run regression tests against changes in 2377 the interpreter code. It also enables test stubs for eBPF maps and 2378 verifier used by user space verifier testsuite. 2379 2380 If unsure, say N. 2381 2382config TEST_BLACKHOLE_DEV 2383 tristate "Test blackhole netdev functionality" 2384 depends on m && NET 2385 help 2386 This builds the "test_blackhole_dev" module that validates the 2387 data path through this blackhole netdev. 2388 2389 If unsure, say N. 2390 2391config FIND_BIT_BENCHMARK 2392 tristate "Test find_bit functions" 2393 help 2394 This builds the "test_find_bit" module that measure find_*_bit() 2395 functions performance. 2396 2397 If unsure, say N. 2398 2399config TEST_FIRMWARE 2400 tristate "Test firmware loading via userspace interface" 2401 depends on FW_LOADER 2402 help 2403 This builds the "test_firmware" module that creates a userspace 2404 interface for testing firmware loading. This can be used to 2405 control the triggering of firmware loading without needing an 2406 actual firmware-using device. The contents can be rechecked by 2407 userspace. 2408 2409 If unsure, say N. 2410 2411config TEST_SYSCTL 2412 tristate "sysctl test driver" 2413 depends on PROC_SYSCTL 2414 help 2415 This builds the "test_sysctl" module. This driver enables to test the 2416 proc sysctl interfaces available to drivers safely without affecting 2417 production knobs which might alter system functionality. 2418 2419 If unsure, say N. 2420 2421config BITFIELD_KUNIT 2422 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2423 depends on KUNIT 2424 default KUNIT_ALL_TESTS 2425 help 2426 Enable this option to test the bitfield functions at boot. 2427 2428 KUnit tests run during boot and output the results to the debug log 2429 in TAP format (http://testanything.org/). Only useful for kernel devs 2430 running the KUnit test harness, and not intended for inclusion into a 2431 production build. 2432 2433 For more information on KUnit and unit tests in general please refer 2434 to the KUnit documentation in Documentation/dev-tools/kunit/. 2435 2436 If unsure, say N. 2437 2438config HASH_KUNIT_TEST 2439 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2440 depends on KUNIT 2441 default KUNIT_ALL_TESTS 2442 help 2443 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2444 integer (<linux/hash.h>) hash functions on boot. 2445 2446 KUnit tests run during boot and output the results to the debug log 2447 in TAP format (https://testanything.org/). Only useful for kernel devs 2448 running the KUnit test harness, and not intended for inclusion into a 2449 production build. 2450 2451 For more information on KUnit and unit tests in general please refer 2452 to the KUnit documentation in Documentation/dev-tools/kunit/. 2453 2454 This is intended to help people writing architecture-specific 2455 optimized versions. If unsure, say N. 2456 2457config RESOURCE_KUNIT_TEST 2458 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2459 depends on KUNIT 2460 default KUNIT_ALL_TESTS 2461 help 2462 This builds the resource API unit test. 2463 Tests the logic of API provided by resource.c and ioport.h. 2464 For more information on KUnit and unit tests in general please refer 2465 to the KUnit documentation in Documentation/dev-tools/kunit/. 2466 2467 If unsure, say N. 2468 2469config SYSCTL_KUNIT_TEST 2470 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2471 depends on KUNIT 2472 default KUNIT_ALL_TESTS 2473 help 2474 This builds the proc sysctl unit test, which runs on boot. 2475 Tests the API contract and implementation correctness of sysctl. 2476 For more information on KUnit and unit tests in general please refer 2477 to the KUnit documentation in Documentation/dev-tools/kunit/. 2478 2479 If unsure, say N. 2480 2481config LIST_KUNIT_TEST 2482 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2483 depends on KUNIT 2484 default KUNIT_ALL_TESTS 2485 help 2486 This builds the linked list KUnit test suite. 2487 It tests that the API and basic functionality of the list_head type 2488 and associated macros. 2489 2490 KUnit tests run during boot and output the results to the debug log 2491 in TAP format (https://testanything.org/). Only useful for kernel devs 2492 running the KUnit test harness, and not intended for inclusion into a 2493 production build. 2494 2495 For more information on KUnit and unit tests in general please refer 2496 to the KUnit documentation in Documentation/dev-tools/kunit/. 2497 2498 If unsure, say N. 2499 2500config LINEAR_RANGES_TEST 2501 tristate "KUnit test for linear_ranges" 2502 depends on KUNIT 2503 select LINEAR_RANGES 2504 help 2505 This builds the linear_ranges unit test, which runs on boot. 2506 Tests the linear_ranges logic correctness. 2507 For more information on KUnit and unit tests in general please refer 2508 to the KUnit documentation in Documentation/dev-tools/kunit/. 2509 2510 If unsure, say N. 2511 2512config CMDLINE_KUNIT_TEST 2513 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2514 depends on KUNIT 2515 default KUNIT_ALL_TESTS 2516 help 2517 This builds the cmdline API unit test. 2518 Tests the logic of API provided by cmdline.c. 2519 For more information on KUnit and unit tests in general please refer 2520 to the KUnit documentation in Documentation/dev-tools/kunit/. 2521 2522 If unsure, say N. 2523 2524config BITS_TEST 2525 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2526 depends on KUNIT 2527 default KUNIT_ALL_TESTS 2528 help 2529 This builds the bits unit test. 2530 Tests the logic of macros defined in bits.h. 2531 For more information on KUnit and unit tests in general please refer 2532 to the KUnit documentation in Documentation/dev-tools/kunit/. 2533 2534 If unsure, say N. 2535 2536config SLUB_KUNIT_TEST 2537 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2538 depends on SLUB_DEBUG && KUNIT 2539 default KUNIT_ALL_TESTS 2540 help 2541 This builds SLUB allocator unit test. 2542 Tests SLUB cache debugging functionality. 2543 For more information on KUnit and unit tests in general please refer 2544 to the KUnit documentation in Documentation/dev-tools/kunit/. 2545 2546 If unsure, say N. 2547 2548config RATIONAL_KUNIT_TEST 2549 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2550 depends on KUNIT && RATIONAL 2551 default KUNIT_ALL_TESTS 2552 help 2553 This builds the rational math unit test. 2554 For more information on KUnit and unit tests in general please refer 2555 to the KUnit documentation in Documentation/dev-tools/kunit/. 2556 2557 If unsure, say N. 2558 2559config MEMCPY_KUNIT_TEST 2560 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2561 depends on KUNIT 2562 default KUNIT_ALL_TESTS 2563 help 2564 Builds unit tests for memcpy(), memmove(), and memset() functions. 2565 For more information on KUnit and unit tests in general please refer 2566 to the KUnit documentation in Documentation/dev-tools/kunit/. 2567 2568 If unsure, say N. 2569 2570config IS_SIGNED_TYPE_KUNIT_TEST 2571 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2572 depends on KUNIT 2573 default KUNIT_ALL_TESTS 2574 help 2575 Builds unit tests for the is_signed_type() macro. 2576 2577 For more information on KUnit and unit tests in general please refer 2578 to the KUnit documentation in Documentation/dev-tools/kunit/. 2579 2580 If unsure, say N. 2581 2582config OVERFLOW_KUNIT_TEST 2583 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2584 depends on KUNIT 2585 default KUNIT_ALL_TESTS 2586 help 2587 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2588 related functions. 2589 2590 For more information on KUnit and unit tests in general please refer 2591 to the KUnit documentation in Documentation/dev-tools/kunit/. 2592 2593 If unsure, say N. 2594 2595config STACKINIT_KUNIT_TEST 2596 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2597 depends on KUNIT 2598 default KUNIT_ALL_TESTS 2599 help 2600 Test if the kernel is zero-initializing stack variables and 2601 padding. Coverage is controlled by compiler flags, 2602 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2603 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2604 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2605 2606config FORTIFY_KUNIT_TEST 2607 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2608 depends on KUNIT && FORTIFY_SOURCE 2609 default KUNIT_ALL_TESTS 2610 help 2611 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2612 by the str*() and mem*() family of functions. For testing runtime 2613 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2614 2615config HW_BREAKPOINT_KUNIT_TEST 2616 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2617 depends on HAVE_HW_BREAKPOINT 2618 depends on KUNIT=y 2619 default KUNIT_ALL_TESTS 2620 help 2621 Tests for hw_breakpoint constraints accounting. 2622 2623 If unsure, say N. 2624 2625config STRSCPY_KUNIT_TEST 2626 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2627 depends on KUNIT 2628 default KUNIT_ALL_TESTS 2629 2630config SIPHASH_KUNIT_TEST 2631 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2632 depends on KUNIT 2633 default KUNIT_ALL_TESTS 2634 help 2635 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2636 functions on boot (or module load). 2637 2638 This is intended to help people writing architecture-specific 2639 optimized versions. If unsure, say N. 2640 2641config TEST_UDELAY 2642 tristate "udelay test driver" 2643 help 2644 This builds the "udelay_test" module that helps to make sure 2645 that udelay() is working properly. 2646 2647 If unsure, say N. 2648 2649config TEST_STATIC_KEYS 2650 tristate "Test static keys" 2651 depends on m 2652 help 2653 Test the static key interfaces. 2654 2655 If unsure, say N. 2656 2657config TEST_DYNAMIC_DEBUG 2658 tristate "Test DYNAMIC_DEBUG" 2659 depends on DYNAMIC_DEBUG 2660 help 2661 This module registers a tracer callback to count enabled 2662 pr_debugs in a 'do_debugging' function, then alters their 2663 enablements, calls the function, and compares counts. 2664 2665 If unsure, say N. 2666 2667config TEST_KMOD 2668 tristate "kmod stress tester" 2669 depends on m 2670 depends on NETDEVICES && NET_CORE && INET # for TUN 2671 depends on BLOCK 2672 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2673 select TEST_LKM 2674 select XFS_FS 2675 select TUN 2676 select BTRFS_FS 2677 help 2678 Test the kernel's module loading mechanism: kmod. kmod implements 2679 support to load modules using the Linux kernel's usermode helper. 2680 This test provides a series of tests against kmod. 2681 2682 Although technically you can either build test_kmod as a module or 2683 into the kernel we disallow building it into the kernel since 2684 it stress tests request_module() and this will very likely cause 2685 some issues by taking over precious threads available from other 2686 module load requests, ultimately this could be fatal. 2687 2688 To run tests run: 2689 2690 tools/testing/selftests/kmod/kmod.sh --help 2691 2692 If unsure, say N. 2693 2694config TEST_DEBUG_VIRTUAL 2695 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2696 depends on DEBUG_VIRTUAL 2697 help 2698 Test the kernel's ability to detect incorrect calls to 2699 virt_to_phys() done against the non-linear part of the 2700 kernel's virtual address map. 2701 2702 If unsure, say N. 2703 2704config TEST_MEMCAT_P 2705 tristate "Test memcat_p() helper function" 2706 help 2707 Test the memcat_p() helper for correctly merging two 2708 pointer arrays together. 2709 2710 If unsure, say N. 2711 2712config TEST_LIVEPATCH 2713 tristate "Test livepatching" 2714 default n 2715 depends on DYNAMIC_DEBUG 2716 depends on LIVEPATCH 2717 depends on m 2718 help 2719 Test kernel livepatching features for correctness. The tests will 2720 load test modules that will be livepatched in various scenarios. 2721 2722 To run all the livepatching tests: 2723 2724 make -C tools/testing/selftests TARGETS=livepatch run_tests 2725 2726 Alternatively, individual tests may be invoked: 2727 2728 tools/testing/selftests/livepatch/test-callbacks.sh 2729 tools/testing/selftests/livepatch/test-livepatch.sh 2730 tools/testing/selftests/livepatch/test-shadow-vars.sh 2731 2732 If unsure, say N. 2733 2734config TEST_OBJAGG 2735 tristate "Perform selftest on object aggreration manager" 2736 default n 2737 depends on OBJAGG 2738 help 2739 Enable this option to test object aggregation manager on boot 2740 (or module load). 2741 2742config TEST_MEMINIT 2743 tristate "Test heap/page initialization" 2744 help 2745 Test if the kernel is zero-initializing heap and page allocations. 2746 This can be useful to test init_on_alloc and init_on_free features. 2747 2748 If unsure, say N. 2749 2750config TEST_HMM 2751 tristate "Test HMM (Heterogeneous Memory Management)" 2752 depends on TRANSPARENT_HUGEPAGE 2753 depends on DEVICE_PRIVATE 2754 select HMM_MIRROR 2755 select MMU_NOTIFIER 2756 help 2757 This is a pseudo device driver solely for testing HMM. 2758 Say M here if you want to build the HMM test module. 2759 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2760 2761 If unsure, say N. 2762 2763config TEST_FREE_PAGES 2764 tristate "Test freeing pages" 2765 help 2766 Test that a memory leak does not occur due to a race between 2767 freeing a block of pages and a speculative page reference. 2768 Loading this module is safe if your kernel has the bug fixed. 2769 If the bug is not fixed, it will leak gigabytes of memory and 2770 probably OOM your system. 2771 2772config TEST_FPU 2773 tristate "Test floating point operations in kernel space" 2774 depends on X86 && !KCOV_INSTRUMENT_ALL 2775 help 2776 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2777 which will trigger a sequence of floating point operations. This is used 2778 for self-testing floating point control register setting in 2779 kernel_fpu_begin(). 2780 2781 If unsure, say N. 2782 2783config TEST_CLOCKSOURCE_WATCHDOG 2784 tristate "Test clocksource watchdog in kernel space" 2785 depends on CLOCKSOURCE_WATCHDOG 2786 help 2787 Enable this option to create a kernel module that will trigger 2788 a test of the clocksource watchdog. This module may be loaded 2789 via modprobe or insmod in which case it will run upon being 2790 loaded, or it may be built in, in which case it will run 2791 shortly after boot. 2792 2793 If unsure, say N. 2794 2795endif # RUNTIME_TESTING_MENU 2796 2797config ARCH_USE_MEMTEST 2798 bool 2799 help 2800 An architecture should select this when it uses early_memtest() 2801 during boot process. 2802 2803config MEMTEST 2804 bool "Memtest" 2805 depends on ARCH_USE_MEMTEST 2806 help 2807 This option adds a kernel parameter 'memtest', which allows memtest 2808 to be set and executed. 2809 memtest=0, mean disabled; -- default 2810 memtest=1, mean do 1 test pattern; 2811 ... 2812 memtest=17, mean do 17 test patterns. 2813 If you are unsure how to answer this question, answer N. 2814 2815 2816 2817config HYPERV_TESTING 2818 bool "Microsoft Hyper-V driver testing" 2819 default n 2820 depends on HYPERV && DEBUG_FS 2821 help 2822 Select this option to enable Hyper-V vmbus testing. 2823 2824endmenu # "Kernel Testing and Coverage" 2825 2826menu "Rust hacking" 2827 2828config RUST_DEBUG_ASSERTIONS 2829 bool "Debug assertions" 2830 depends on RUST 2831 help 2832 Enables rustc's `-Cdebug-assertions` codegen option. 2833 2834 This flag lets you turn `cfg(debug_assertions)` conditional 2835 compilation on or off. This can be used to enable extra debugging 2836 code in development but not in production. For example, it controls 2837 the behavior of the standard library's `debug_assert!` macro. 2838 2839 Note that this will apply to all Rust code, including `core`. 2840 2841 If unsure, say N. 2842 2843config RUST_OVERFLOW_CHECKS 2844 bool "Overflow checks" 2845 default y 2846 depends on RUST 2847 help 2848 Enables rustc's `-Coverflow-checks` codegen option. 2849 2850 This flag allows you to control the behavior of runtime integer 2851 overflow. When overflow-checks are enabled, a Rust panic will occur 2852 on overflow. 2853 2854 Note that this will apply to all Rust code, including `core`. 2855 2856 If unsure, say Y. 2857 2858config RUST_BUILD_ASSERT_ALLOW 2859 bool "Allow unoptimized build-time assertions" 2860 depends on RUST 2861 help 2862 Controls how are `build_error!` and `build_assert!` handled during build. 2863 2864 If calls to them exist in the binary, it may indicate a violated invariant 2865 or that the optimizer failed to verify the invariant during compilation. 2866 2867 This should not happen, thus by default the build is aborted. However, 2868 as an escape hatch, you can choose Y here to ignore them during build 2869 and let the check be carried at runtime (with `panic!` being called if 2870 the check fails). 2871 2872 If unsure, say N. 2873 2874endmenu # "Rust" 2875 2876source "Documentation/Kconfig" 2877 2878endmenu # Kernel hacking 2879