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 315config DEBUG_INFO_COMPRESSED 316 bool "Compressed debugging information" 317 depends on $(cc-option,-gz=zlib) 318 depends on $(ld-option,--compress-debug-sections=zlib) 319 help 320 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 321 5.0+, binutils 2.26+, and zlib. 322 323 Users of dpkg-deb via scripts/package/builddeb may find an increase in 324 size of their debug .deb packages with this config set, due to the 325 debug info being compressed with zlib, then the object files being 326 recompressed with a different compression scheme. But this is still 327 preferable to setting $KDEB_COMPRESS to "none" which would be even 328 larger. 329 330config DEBUG_INFO_SPLIT 331 bool "Produce split debuginfo in .dwo files" 332 depends on $(cc-option,-gsplit-dwarf) 333 help 334 Generate debug info into separate .dwo files. This significantly 335 reduces the build directory size for builds with DEBUG_INFO, 336 because it stores the information only once on disk in .dwo 337 files instead of multiple times in object files and executables. 338 In addition the debug information is also compressed. 339 340 Requires recent gcc (4.7+) and recent gdb/binutils. 341 Any tool that packages or reads debug information would need 342 to know about the .dwo files and include them. 343 Incompatible with older versions of ccache. 344 345config DEBUG_INFO_BTF 346 bool "Generate BTF typeinfo" 347 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 348 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 349 depends on BPF_SYSCALL 350 depends on !DEBUG_INFO_DWARF5 || PAHOLE_VERSION >= 121 351 help 352 Generate deduplicated BTF type information from DWARF debug info. 353 Turning this on expects presence of pahole tool, which will convert 354 DWARF type info into equivalent deduplicated BTF type info. 355 356config PAHOLE_HAS_SPLIT_BTF 357 def_bool PAHOLE_VERSION >= 119 358 359config PAHOLE_HAS_BTF_TAG 360 def_bool PAHOLE_VERSION >= 123 361 depends on CC_IS_CLANG 362 help 363 Decide whether pahole emits btf_tag attributes (btf_type_tag and 364 btf_decl_tag) or not. Currently only clang compiler implements 365 these attributes, so make the config depend on CC_IS_CLANG. 366 367config DEBUG_INFO_BTF_MODULES 368 def_bool y 369 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 370 help 371 Generate compact split BTF type information for kernel modules. 372 373config MODULE_ALLOW_BTF_MISMATCH 374 bool "Allow loading modules with non-matching BTF type info" 375 depends on DEBUG_INFO_BTF_MODULES 376 help 377 For modules whose split BTF does not match vmlinux, load without 378 BTF rather than refusing to load. The default behavior with 379 module BTF enabled is to reject modules with such mismatches; 380 this option will still load module BTF where possible but ignore 381 it when a mismatch is found. 382 383config GDB_SCRIPTS 384 bool "Provide GDB scripts for kernel debugging" 385 help 386 This creates the required links to GDB helper scripts in the 387 build directory. If you load vmlinux into gdb, the helper 388 scripts will be automatically imported by gdb as well, and 389 additional functions are available to analyze a Linux kernel 390 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 391 for further details. 392 393endif # DEBUG_INFO 394 395config FRAME_WARN 396 int "Warn for stack frames larger than" 397 range 0 8192 398 default 0 if KMSAN 399 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 400 default 2048 if PARISC 401 default 1536 if (!64BIT && XTENSA) 402 default 1280 if KASAN && !64BIT 403 default 1024 if !64BIT 404 default 2048 if 64BIT 405 help 406 Tell the compiler to warn at build time for stack frames larger than this. 407 Setting this too low will cause a lot of warnings. 408 Setting it to 0 disables the warning. 409 410config STRIP_ASM_SYMS 411 bool "Strip assembler-generated symbols during link" 412 default n 413 help 414 Strip internal assembler-generated symbols during a link (symbols 415 that look like '.Lxxx') so they don't pollute the output of 416 get_wchan() and suchlike. 417 418config READABLE_ASM 419 bool "Generate readable assembler code" 420 depends on DEBUG_KERNEL 421 depends on CC_IS_GCC 422 help 423 Disable some compiler optimizations that tend to generate human unreadable 424 assembler output. This may make the kernel slightly slower, but it helps 425 to keep kernel developers who have to stare a lot at assembler listings 426 sane. 427 428config HEADERS_INSTALL 429 bool "Install uapi headers to usr/include" 430 depends on !UML 431 help 432 This option will install uapi headers (headers exported to user-space) 433 into the usr/include directory for use during the kernel build. 434 This is unneeded for building the kernel itself, but needed for some 435 user-space program samples. It is also needed by some features such 436 as uapi header sanity checks. 437 438config DEBUG_SECTION_MISMATCH 439 bool "Enable full Section mismatch analysis" 440 depends on CC_IS_GCC 441 help 442 The section mismatch analysis checks if there are illegal 443 references from one section to another section. 444 During linktime or runtime, some sections are dropped; 445 any use of code/data previously in these sections would 446 most likely result in an oops. 447 In the code, functions and variables are annotated with 448 __init,, etc. (see the full list in include/linux/init.h), 449 which results in the code/data being placed in specific sections. 450 The section mismatch analysis is always performed after a full 451 kernel build, and enabling this option causes the following 452 additional step to occur: 453 - Add the option -fno-inline-functions-called-once to gcc commands. 454 When inlining a function annotated with __init in a non-init 455 function, we would lose the section information and thus 456 the analysis would not catch the illegal reference. 457 This option tells gcc to inline less (but it does result in 458 a larger kernel). 459 460config SECTION_MISMATCH_WARN_ONLY 461 bool "Make section mismatch errors non-fatal" 462 default y 463 help 464 If you say N here, the build process will fail if there are any 465 section mismatch, instead of just throwing warnings. 466 467 If unsure, say Y. 468 469config DEBUG_FORCE_FUNCTION_ALIGN_64B 470 bool "Force all function address 64B aligned" 471 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC) 472 select FUNCTION_ALIGNMENT_64B 473 help 474 There are cases that a commit from one domain changes the function 475 address alignment of other domains, and cause magic performance 476 bump (regression or improvement). Enable this option will help to 477 verify if the bump is caused by function alignment changes, while 478 it will slightly increase the kernel size and affect icache usage. 479 480 It is mainly for debug and performance tuning use. 481 482# 483# Select this config option from the architecture Kconfig, if it 484# is preferred to always offer frame pointers as a config 485# option on the architecture (regardless of KERNEL_DEBUG): 486# 487config ARCH_WANT_FRAME_POINTERS 488 bool 489 490config FRAME_POINTER 491 bool "Compile the kernel with frame pointers" 492 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 493 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 494 help 495 If you say Y here the resulting kernel image will be slightly 496 larger and slower, but it gives very useful debugging information 497 in case of kernel bugs. (precise oopses/stacktraces/warnings) 498 499config OBJTOOL 500 bool 501 502config STACK_VALIDATION 503 bool "Compile-time stack metadata validation" 504 depends on HAVE_STACK_VALIDATION && UNWINDER_FRAME_POINTER 505 select OBJTOOL 506 default n 507 help 508 Validate frame pointer rules at compile-time. This helps ensure that 509 runtime stack traces are more reliable. 510 511 For more information, see 512 tools/objtool/Documentation/objtool.txt. 513 514config NOINSTR_VALIDATION 515 bool 516 depends on HAVE_NOINSTR_VALIDATION && DEBUG_ENTRY 517 select OBJTOOL 518 default y 519 520config VMLINUX_MAP 521 bool "Generate vmlinux.map file when linking" 522 depends on EXPERT 523 help 524 Selecting this option will pass "-Map=vmlinux.map" to ld 525 when linking vmlinux. That file can be useful for verifying 526 and debugging magic section games, and for seeing which 527 pieces of code get eliminated with 528 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 529 530config DEBUG_FORCE_WEAK_PER_CPU 531 bool "Force weak per-cpu definitions" 532 depends on DEBUG_KERNEL 533 help 534 s390 and alpha require percpu variables in modules to be 535 defined weak to work around addressing range issue which 536 puts the following two restrictions on percpu variable 537 definitions. 538 539 1. percpu symbols must be unique whether static or not 540 2. percpu variables can't be defined inside a function 541 542 To ensure that generic code follows the above rules, this 543 option forces all percpu variables to be defined as weak. 544 545endmenu # "Compiler options" 546 547menu "Generic Kernel Debugging Instruments" 548 549config MAGIC_SYSRQ 550 bool "Magic SysRq key" 551 depends on !UML 552 help 553 If you say Y here, you will have some control over the system even 554 if the system crashes for example during kernel debugging (e.g., you 555 will be able to flush the buffer cache to disk, reboot the system 556 immediately or dump some status information). This is accomplished 557 by pressing various keys while holding SysRq (Alt+PrintScreen). It 558 also works on a serial console (on PC hardware at least), if you 559 send a BREAK and then within 5 seconds a command keypress. The 560 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 561 Don't say Y unless you really know what this hack does. 562 563config MAGIC_SYSRQ_DEFAULT_ENABLE 564 hex "Enable magic SysRq key functions by default" 565 depends on MAGIC_SYSRQ 566 default 0x1 567 help 568 Specifies which SysRq key functions are enabled by default. 569 This may be set to 1 or 0 to enable or disable them all, or 570 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 571 572config MAGIC_SYSRQ_SERIAL 573 bool "Enable magic SysRq key over serial" 574 depends on MAGIC_SYSRQ 575 default y 576 help 577 Many embedded boards have a disconnected TTL level serial which can 578 generate some garbage that can lead to spurious false sysrq detects. 579 This option allows you to decide whether you want to enable the 580 magic SysRq key. 581 582config MAGIC_SYSRQ_SERIAL_SEQUENCE 583 string "Char sequence that enables magic SysRq over serial" 584 depends on MAGIC_SYSRQ_SERIAL 585 default "" 586 help 587 Specifies a sequence of characters that can follow BREAK to enable 588 SysRq on a serial console. 589 590 If unsure, leave an empty string and the option will not be enabled. 591 592config DEBUG_FS 593 bool "Debug Filesystem" 594 help 595 debugfs is a virtual file system that kernel developers use to put 596 debugging files into. Enable this option to be able to read and 597 write to these files. 598 599 For detailed documentation on the debugfs API, see 600 Documentation/filesystems/. 601 602 If unsure, say N. 603 604choice 605 prompt "Debugfs default access" 606 depends on DEBUG_FS 607 default DEBUG_FS_ALLOW_ALL 608 help 609 This selects the default access restrictions for debugfs. 610 It can be overridden with kernel command line option 611 debugfs=[on,no-mount,off]. The restrictions apply for API access 612 and filesystem registration. 613 614config DEBUG_FS_ALLOW_ALL 615 bool "Access normal" 616 help 617 No restrictions apply. Both API and filesystem registration 618 is on. This is the normal default operation. 619 620config DEBUG_FS_DISALLOW_MOUNT 621 bool "Do not register debugfs as filesystem" 622 help 623 The API is open but filesystem is not loaded. Clients can still do 624 their work and read with debug tools that do not need 625 debugfs filesystem. 626 627config DEBUG_FS_ALLOW_NONE 628 bool "No access" 629 help 630 Access is off. Clients get -PERM when trying to create nodes in 631 debugfs tree and debugfs is not registered as a filesystem. 632 Client can then back-off or continue without debugfs access. 633 634endchoice 635 636source "lib/Kconfig.kgdb" 637source "lib/Kconfig.ubsan" 638source "lib/Kconfig.kcsan" 639 640endmenu 641 642menu "Networking Debugging" 643 644source "net/Kconfig.debug" 645 646endmenu # "Networking Debugging" 647 648menu "Memory Debugging" 649 650source "mm/Kconfig.debug" 651 652config DEBUG_OBJECTS 653 bool "Debug object operations" 654 depends on DEBUG_KERNEL 655 help 656 If you say Y here, additional code will be inserted into the 657 kernel to track the life time of various objects and validate 658 the operations on those objects. 659 660config DEBUG_OBJECTS_SELFTEST 661 bool "Debug objects selftest" 662 depends on DEBUG_OBJECTS 663 help 664 This enables the selftest of the object debug code. 665 666config DEBUG_OBJECTS_FREE 667 bool "Debug objects in freed memory" 668 depends on DEBUG_OBJECTS 669 help 670 This enables checks whether a k/v free operation frees an area 671 which contains an object which has not been deactivated 672 properly. This can make kmalloc/kfree-intensive workloads 673 much slower. 674 675config DEBUG_OBJECTS_TIMERS 676 bool "Debug timer objects" 677 depends on DEBUG_OBJECTS 678 help 679 If you say Y here, additional code will be inserted into the 680 timer routines to track the life time of timer objects and 681 validate the timer operations. 682 683config DEBUG_OBJECTS_WORK 684 bool "Debug work objects" 685 depends on DEBUG_OBJECTS 686 help 687 If you say Y here, additional code will be inserted into the 688 work queue routines to track the life time of work objects and 689 validate the work operations. 690 691config DEBUG_OBJECTS_RCU_HEAD 692 bool "Debug RCU callbacks objects" 693 depends on DEBUG_OBJECTS 694 help 695 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 696 697config DEBUG_OBJECTS_PERCPU_COUNTER 698 bool "Debug percpu counter objects" 699 depends on DEBUG_OBJECTS 700 help 701 If you say Y here, additional code will be inserted into the 702 percpu counter routines to track the life time of percpu counter 703 objects and validate the percpu counter operations. 704 705config DEBUG_OBJECTS_ENABLE_DEFAULT 706 int "debug_objects bootup default value (0-1)" 707 range 0 1 708 default "1" 709 depends on DEBUG_OBJECTS 710 help 711 Debug objects boot parameter default value 712 713config SHRINKER_DEBUG 714 bool "Enable shrinker debugging support" 715 depends on DEBUG_FS 716 help 717 Say Y to enable the shrinker debugfs interface which provides 718 visibility into the kernel memory shrinkers subsystem. 719 Disable it to avoid an extra memory footprint. 720 721config HAVE_DEBUG_KMEMLEAK 722 bool 723 724config DEBUG_KMEMLEAK 725 bool "Kernel memory leak detector" 726 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 727 select DEBUG_FS 728 select STACKTRACE if STACKTRACE_SUPPORT 729 select KALLSYMS 730 select CRC32 731 select STACKDEPOT 732 help 733 Say Y here if you want to enable the memory leak 734 detector. The memory allocation/freeing is traced in a way 735 similar to the Boehm's conservative garbage collector, the 736 difference being that the orphan objects are not freed but 737 only shown in /sys/kernel/debug/kmemleak. Enabling this 738 feature will introduce an overhead to memory 739 allocations. See Documentation/dev-tools/kmemleak.rst for more 740 details. 741 742 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 743 of finding leaks due to the slab objects poisoning. 744 745 In order to access the kmemleak file, debugfs needs to be 746 mounted (usually at /sys/kernel/debug). 747 748config DEBUG_KMEMLEAK_MEM_POOL_SIZE 749 int "Kmemleak memory pool size" 750 depends on DEBUG_KMEMLEAK 751 range 200 1000000 752 default 16000 753 help 754 Kmemleak must track all the memory allocations to avoid 755 reporting false positives. Since memory may be allocated or 756 freed before kmemleak is fully initialised, use a static pool 757 of metadata objects to track such callbacks. After kmemleak is 758 fully initialised, this memory pool acts as an emergency one 759 if slab allocations fail. 760 761config DEBUG_KMEMLEAK_TEST 762 tristate "Simple test for the kernel memory leak detector" 763 depends on DEBUG_KMEMLEAK && m 764 help 765 This option enables a module that explicitly leaks memory. 766 767 If unsure, say N. 768 769config DEBUG_KMEMLEAK_DEFAULT_OFF 770 bool "Default kmemleak to off" 771 depends on DEBUG_KMEMLEAK 772 help 773 Say Y here to disable kmemleak by default. It can then be enabled 774 on the command line via kmemleak=on. 775 776config DEBUG_KMEMLEAK_AUTO_SCAN 777 bool "Enable kmemleak auto scan thread on boot up" 778 default y 779 depends on DEBUG_KMEMLEAK 780 help 781 Depending on the cpu, kmemleak scan may be cpu intensive and can 782 stall user tasks at times. This option enables/disables automatic 783 kmemleak scan at boot up. 784 785 Say N here to disable kmemleak auto scan thread to stop automatic 786 scanning. Disabling this option disables automatic reporting of 787 memory leaks. 788 789 If unsure, say Y. 790 791config DEBUG_STACK_USAGE 792 bool "Stack utilization instrumentation" 793 depends on DEBUG_KERNEL && !IA64 794 help 795 Enables the display of the minimum amount of free stack which each 796 task has ever had available in the sysrq-T and sysrq-P debug output. 797 798 This option will slow down process creation somewhat. 799 800config SCHED_STACK_END_CHECK 801 bool "Detect stack corruption on calls to schedule()" 802 depends on DEBUG_KERNEL 803 default n 804 help 805 This option checks for a stack overrun on calls to schedule(). 806 If the stack end location is found to be over written always panic as 807 the content of the corrupted region can no longer be trusted. 808 This is to ensure no erroneous behaviour occurs which could result in 809 data corruption or a sporadic crash at a later stage once the region 810 is examined. The runtime overhead introduced is minimal. 811 812config ARCH_HAS_DEBUG_VM_PGTABLE 813 bool 814 help 815 An architecture should select this when it can successfully 816 build and run DEBUG_VM_PGTABLE. 817 818config DEBUG_VM_IRQSOFF 819 def_bool DEBUG_VM && !PREEMPT_RT 820 821config DEBUG_VM 822 bool "Debug VM" 823 depends on DEBUG_KERNEL 824 help 825 Enable this to turn on extended checks in the virtual-memory system 826 that may impact performance. 827 828 If unsure, say N. 829 830config DEBUG_VM_MAPLE_TREE 831 bool "Debug VM maple trees" 832 depends on DEBUG_VM 833 select DEBUG_MAPLE_TREE 834 help 835 Enable VM maple tree debugging information and extra validations. 836 837 If unsure, say N. 838 839config DEBUG_VM_RB 840 bool "Debug VM red-black trees" 841 depends on DEBUG_VM 842 help 843 Enable VM red-black tree debugging information and extra validations. 844 845 If unsure, say N. 846 847config DEBUG_VM_PGFLAGS 848 bool "Debug page-flags operations" 849 depends on DEBUG_VM 850 help 851 Enables extra validation on page flags operations. 852 853 If unsure, say N. 854 855config DEBUG_VM_PGTABLE 856 bool "Debug arch page table for semantics compliance" 857 depends on MMU 858 depends on ARCH_HAS_DEBUG_VM_PGTABLE 859 default y if DEBUG_VM 860 help 861 This option provides a debug method which can be used to test 862 architecture page table helper functions on various platforms in 863 verifying if they comply with expected generic MM semantics. This 864 will help architecture code in making sure that any changes or 865 new additions of these helpers still conform to expected 866 semantics of the generic MM. Platforms will have to opt in for 867 this through ARCH_HAS_DEBUG_VM_PGTABLE. 868 869 If unsure, say N. 870 871config ARCH_HAS_DEBUG_VIRTUAL 872 bool 873 874config DEBUG_VIRTUAL 875 bool "Debug VM translations" 876 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 877 help 878 Enable some costly sanity checks in virtual to page code. This can 879 catch mistakes with virt_to_page() and friends. 880 881 If unsure, say N. 882 883config DEBUG_NOMMU_REGIONS 884 bool "Debug the global anon/private NOMMU mapping region tree" 885 depends on DEBUG_KERNEL && !MMU 886 help 887 This option causes the global tree of anonymous and private mapping 888 regions to be regularly checked for invalid topology. 889 890config DEBUG_MEMORY_INIT 891 bool "Debug memory initialisation" if EXPERT 892 default !EXPERT 893 help 894 Enable this for additional checks during memory initialisation. 895 The sanity checks verify aspects of the VM such as the memory model 896 and other information provided by the architecture. Verbose 897 information will be printed at KERN_DEBUG loglevel depending 898 on the mminit_loglevel= command-line option. 899 900 If unsure, say Y 901 902config MEMORY_NOTIFIER_ERROR_INJECT 903 tristate "Memory hotplug notifier error injection module" 904 depends on MEMORY_HOTPLUG && NOTIFIER_ERROR_INJECTION 905 help 906 This option provides the ability to inject artificial errors to 907 memory hotplug notifier chain callbacks. It is controlled through 908 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 909 910 If the notifier call chain should be failed with some events 911 notified, write the error code to "actions/<notifier event>/error". 912 913 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 914 915 # cd /sys/kernel/debug/notifier-error-inject/memory 916 # echo -12 > actions/MEM_GOING_OFFLINE/error 917 # echo offline > /sys/devices/system/memory/memoryXXX/state 918 bash: echo: write error: Cannot allocate memory 919 920 To compile this code as a module, choose M here: the module will 921 be called memory-notifier-error-inject. 922 923 If unsure, say N. 924 925config DEBUG_PER_CPU_MAPS 926 bool "Debug access to per_cpu maps" 927 depends on DEBUG_KERNEL 928 depends on SMP 929 help 930 Say Y to verify that the per_cpu map being accessed has 931 been set up. This adds a fair amount of code to kernel memory 932 and decreases performance. 933 934 Say N if unsure. 935 936config DEBUG_KMAP_LOCAL 937 bool "Debug kmap_local temporary mappings" 938 depends on DEBUG_KERNEL && KMAP_LOCAL 939 help 940 This option enables additional error checking for the kmap_local 941 infrastructure. Disable for production use. 942 943config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 944 bool 945 946config DEBUG_KMAP_LOCAL_FORCE_MAP 947 bool "Enforce kmap_local temporary mappings" 948 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 949 select KMAP_LOCAL 950 select DEBUG_KMAP_LOCAL 951 help 952 This option enforces temporary mappings through the kmap_local 953 mechanism for non-highmem pages and on non-highmem systems. 954 Disable this for production systems! 955 956config DEBUG_HIGHMEM 957 bool "Highmem debugging" 958 depends on DEBUG_KERNEL && HIGHMEM 959 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 960 select DEBUG_KMAP_LOCAL 961 help 962 This option enables additional error checking for high memory 963 systems. Disable for production systems. 964 965config HAVE_DEBUG_STACKOVERFLOW 966 bool 967 968config DEBUG_STACKOVERFLOW 969 bool "Check for stack overflows" 970 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 971 help 972 Say Y here if you want to check for overflows of kernel, IRQ 973 and exception stacks (if your architecture uses them). This 974 option will show detailed messages if free stack space drops 975 below a certain limit. 976 977 These kinds of bugs usually occur when call-chains in the 978 kernel get too deep, especially when interrupts are 979 involved. 980 981 Use this in cases where you see apparently random memory 982 corruption, especially if it appears in 'struct thread_info' 983 984 If in doubt, say "N". 985 986source "lib/Kconfig.kasan" 987source "lib/Kconfig.kfence" 988source "lib/Kconfig.kmsan" 989 990endmenu # "Memory Debugging" 991 992config DEBUG_SHIRQ 993 bool "Debug shared IRQ handlers" 994 depends on DEBUG_KERNEL 995 help 996 Enable this to generate a spurious interrupt just before a shared 997 interrupt handler is deregistered (generating one when registering 998 is currently disabled). Drivers need to handle this correctly. Some 999 don't and need to be caught. 1000 1001menu "Debug Oops, Lockups and Hangs" 1002 1003config PANIC_ON_OOPS 1004 bool "Panic on Oops" 1005 help 1006 Say Y here to enable the kernel to panic when it oopses. This 1007 has the same effect as setting oops=panic on the kernel command 1008 line. 1009 1010 This feature is useful to ensure that the kernel does not do 1011 anything erroneous after an oops which could result in data 1012 corruption or other issues. 1013 1014 Say N if unsure. 1015 1016config PANIC_ON_OOPS_VALUE 1017 int 1018 range 0 1 1019 default 0 if !PANIC_ON_OOPS 1020 default 1 if PANIC_ON_OOPS 1021 1022config PANIC_TIMEOUT 1023 int "panic timeout" 1024 default 0 1025 help 1026 Set the timeout value (in seconds) until a reboot occurs when 1027 the kernel panics. If n = 0, then we wait forever. A timeout 1028 value n > 0 will wait n seconds before rebooting, while a timeout 1029 value n < 0 will reboot immediately. 1030 1031config LOCKUP_DETECTOR 1032 bool 1033 1034config SOFTLOCKUP_DETECTOR 1035 bool "Detect Soft Lockups" 1036 depends on DEBUG_KERNEL && !S390 1037 select LOCKUP_DETECTOR 1038 help 1039 Say Y here to enable the kernel to act as a watchdog to detect 1040 soft lockups. 1041 1042 Softlockups are bugs that cause the kernel to loop in kernel 1043 mode for more than 20 seconds, without giving other tasks a 1044 chance to run. The current stack trace is displayed upon 1045 detection and the system will stay locked up. 1046 1047config BOOTPARAM_SOFTLOCKUP_PANIC 1048 bool "Panic (Reboot) On Soft Lockups" 1049 depends on SOFTLOCKUP_DETECTOR 1050 help 1051 Say Y here to enable the kernel to panic on "soft lockups", 1052 which are bugs that cause the kernel to loop in kernel 1053 mode for more than 20 seconds (configurable using the watchdog_thresh 1054 sysctl), without giving other tasks a chance to run. 1055 1056 The panic can be used in combination with panic_timeout, 1057 to cause the system to reboot automatically after a 1058 lockup has been detected. This feature is useful for 1059 high-availability systems that have uptime guarantees and 1060 where a lockup must be resolved ASAP. 1061 1062 Say N if unsure. 1063 1064config HARDLOCKUP_DETECTOR_PERF 1065 bool 1066 select SOFTLOCKUP_DETECTOR 1067 1068# 1069# Enables a timestamp based low pass filter to compensate for perf based 1070# hard lockup detection which runs too fast due to turbo modes. 1071# 1072config HARDLOCKUP_CHECK_TIMESTAMP 1073 bool 1074 1075# 1076# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1077# lockup detector rather than the perf based detector. 1078# 1079config HARDLOCKUP_DETECTOR 1080 bool "Detect Hard Lockups" 1081 depends on DEBUG_KERNEL && !S390 1082 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1083 select LOCKUP_DETECTOR 1084 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1085 help 1086 Say Y here to enable the kernel to act as a watchdog to detect 1087 hard lockups. 1088 1089 Hardlockups are bugs that cause the CPU to loop in kernel mode 1090 for more than 10 seconds, without letting other interrupts have a 1091 chance to run. The current stack trace is displayed upon detection 1092 and the system will stay locked up. 1093 1094config BOOTPARAM_HARDLOCKUP_PANIC 1095 bool "Panic (Reboot) On Hard Lockups" 1096 depends on HARDLOCKUP_DETECTOR 1097 help 1098 Say Y here to enable the kernel to panic on "hard lockups", 1099 which are bugs that cause the kernel to loop in kernel 1100 mode with interrupts disabled for more than 10 seconds (configurable 1101 using the watchdog_thresh sysctl). 1102 1103 Say N if unsure. 1104 1105config DETECT_HUNG_TASK 1106 bool "Detect Hung Tasks" 1107 depends on DEBUG_KERNEL 1108 default SOFTLOCKUP_DETECTOR 1109 help 1110 Say Y here to enable the kernel to detect "hung tasks", 1111 which are bugs that cause the task to be stuck in 1112 uninterruptible "D" state indefinitely. 1113 1114 When a hung task is detected, the kernel will print the 1115 current stack trace (which you should report), but the 1116 task will stay in uninterruptible state. If lockdep is 1117 enabled then all held locks will also be reported. This 1118 feature has negligible overhead. 1119 1120config DEFAULT_HUNG_TASK_TIMEOUT 1121 int "Default timeout for hung task detection (in seconds)" 1122 depends on DETECT_HUNG_TASK 1123 default 120 1124 help 1125 This option controls the default timeout (in seconds) used 1126 to determine when a task has become non-responsive and should 1127 be considered hung. 1128 1129 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1130 sysctl or by writing a value to 1131 /proc/sys/kernel/hung_task_timeout_secs. 1132 1133 A timeout of 0 disables the check. The default is two minutes. 1134 Keeping the default should be fine in most cases. 1135 1136config BOOTPARAM_HUNG_TASK_PANIC 1137 bool "Panic (Reboot) On Hung Tasks" 1138 depends on DETECT_HUNG_TASK 1139 help 1140 Say Y here to enable the kernel to panic on "hung tasks", 1141 which are bugs that cause the kernel to leave a task stuck 1142 in uninterruptible "D" state. 1143 1144 The panic can be used in combination with panic_timeout, 1145 to cause the system to reboot automatically after a 1146 hung task has been detected. This feature is useful for 1147 high-availability systems that have uptime guarantees and 1148 where a hung tasks must be resolved ASAP. 1149 1150 Say N if unsure. 1151 1152config WQ_WATCHDOG 1153 bool "Detect Workqueue Stalls" 1154 depends on DEBUG_KERNEL 1155 help 1156 Say Y here to enable stall detection on workqueues. If a 1157 worker pool doesn't make forward progress on a pending work 1158 item for over a given amount of time, 30s by default, a 1159 warning message is printed along with dump of workqueue 1160 state. This can be configured through kernel parameter 1161 "workqueue.watchdog_thresh" and its sysfs counterpart. 1162 1163config TEST_LOCKUP 1164 tristate "Test module to generate lockups" 1165 depends on m 1166 help 1167 This builds the "test_lockup" module that helps to make sure 1168 that watchdogs and lockup detectors are working properly. 1169 1170 Depending on module parameters it could emulate soft or hard 1171 lockup, "hung task", or locking arbitrary lock for a long time. 1172 Also it could generate series of lockups with cooling-down periods. 1173 1174 If unsure, say N. 1175 1176endmenu # "Debug lockups and hangs" 1177 1178menu "Scheduler Debugging" 1179 1180config SCHED_DEBUG 1181 bool "Collect scheduler debugging info" 1182 depends on DEBUG_KERNEL && PROC_FS 1183 default y 1184 help 1185 If you say Y here, the /proc/sched_debug file will be provided 1186 that can help debug the scheduler. The runtime overhead of this 1187 option is minimal. 1188 1189config SCHED_INFO 1190 bool 1191 default n 1192 1193config SCHEDSTATS 1194 bool "Collect scheduler statistics" 1195 depends on DEBUG_KERNEL && PROC_FS 1196 select SCHED_INFO 1197 help 1198 If you say Y here, additional code will be inserted into the 1199 scheduler and related routines to collect statistics about 1200 scheduler behavior and provide them in /proc/schedstat. These 1201 stats may be useful for both tuning and debugging the scheduler 1202 If you aren't debugging the scheduler or trying to tune a specific 1203 application, you can say N to avoid the very slight overhead 1204 this adds. 1205 1206endmenu 1207 1208config DEBUG_TIMEKEEPING 1209 bool "Enable extra timekeeping sanity checking" 1210 help 1211 This option will enable additional timekeeping sanity checks 1212 which may be helpful when diagnosing issues where timekeeping 1213 problems are suspected. 1214 1215 This may include checks in the timekeeping hotpaths, so this 1216 option may have a (very small) performance impact to some 1217 workloads. 1218 1219 If unsure, say N. 1220 1221config DEBUG_PREEMPT 1222 bool "Debug preemptible kernel" 1223 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1224 default y 1225 help 1226 If you say Y here then the kernel will use a debug variant of the 1227 commonly used smp_processor_id() function and will print warnings 1228 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1229 will detect preemption count underflows. 1230 1231menu "Lock Debugging (spinlocks, mutexes, etc...)" 1232 1233config LOCK_DEBUGGING_SUPPORT 1234 bool 1235 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1236 default y 1237 1238config PROVE_LOCKING 1239 bool "Lock debugging: prove locking correctness" 1240 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1241 select LOCKDEP 1242 select DEBUG_SPINLOCK 1243 select DEBUG_MUTEXES if !PREEMPT_RT 1244 select DEBUG_RT_MUTEXES if RT_MUTEXES 1245 select DEBUG_RWSEMS 1246 select DEBUG_WW_MUTEX_SLOWPATH 1247 select DEBUG_LOCK_ALLOC 1248 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1249 select TRACE_IRQFLAGS 1250 default n 1251 help 1252 This feature enables the kernel to prove that all locking 1253 that occurs in the kernel runtime is mathematically 1254 correct: that under no circumstance could an arbitrary (and 1255 not yet triggered) combination of observed locking 1256 sequences (on an arbitrary number of CPUs, running an 1257 arbitrary number of tasks and interrupt contexts) cause a 1258 deadlock. 1259 1260 In short, this feature enables the kernel to report locking 1261 related deadlocks before they actually occur. 1262 1263 The proof does not depend on how hard and complex a 1264 deadlock scenario would be to trigger: how many 1265 participant CPUs, tasks and irq-contexts would be needed 1266 for it to trigger. The proof also does not depend on 1267 timing: if a race and a resulting deadlock is possible 1268 theoretically (no matter how unlikely the race scenario 1269 is), it will be proven so and will immediately be 1270 reported by the kernel (once the event is observed that 1271 makes the deadlock theoretically possible). 1272 1273 If a deadlock is impossible (i.e. the locking rules, as 1274 observed by the kernel, are mathematically correct), the 1275 kernel reports nothing. 1276 1277 NOTE: this feature can also be enabled for rwlocks, mutexes 1278 and rwsems - in which case all dependencies between these 1279 different locking variants are observed and mapped too, and 1280 the proof of observed correctness is also maintained for an 1281 arbitrary combination of these separate locking variants. 1282 1283 For more details, see Documentation/locking/lockdep-design.rst. 1284 1285config PROVE_RAW_LOCK_NESTING 1286 bool "Enable raw_spinlock - spinlock nesting checks" 1287 depends on PROVE_LOCKING 1288 default n 1289 help 1290 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1291 that the lock nesting rules for PREEMPT_RT enabled kernels are 1292 not violated. 1293 1294 NOTE: There are known nesting problems. So if you enable this 1295 option expect lockdep splats until these problems have been fully 1296 addressed which is work in progress. This config switch allows to 1297 identify and analyze these problems. It will be removed and the 1298 check permanently enabled once the main issues have been fixed. 1299 1300 If unsure, select N. 1301 1302config LOCK_STAT 1303 bool "Lock usage statistics" 1304 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1305 select LOCKDEP 1306 select DEBUG_SPINLOCK 1307 select DEBUG_MUTEXES if !PREEMPT_RT 1308 select DEBUG_RT_MUTEXES if RT_MUTEXES 1309 select DEBUG_LOCK_ALLOC 1310 default n 1311 help 1312 This feature enables tracking lock contention points 1313 1314 For more details, see Documentation/locking/lockstat.rst 1315 1316 This also enables lock events required by "perf lock", 1317 subcommand of perf. 1318 If you want to use "perf lock", you also need to turn on 1319 CONFIG_EVENT_TRACING. 1320 1321 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1322 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1323 1324config DEBUG_RT_MUTEXES 1325 bool "RT Mutex debugging, deadlock detection" 1326 depends on DEBUG_KERNEL && RT_MUTEXES 1327 help 1328 This allows rt mutex semantics violations and rt mutex related 1329 deadlocks (lockups) to be detected and reported automatically. 1330 1331config DEBUG_SPINLOCK 1332 bool "Spinlock and rw-lock debugging: basic checks" 1333 depends on DEBUG_KERNEL 1334 select UNINLINE_SPIN_UNLOCK 1335 help 1336 Say Y here and build SMP to catch missing spinlock initialization 1337 and certain other kinds of spinlock errors commonly made. This is 1338 best used in conjunction with the NMI watchdog so that spinlock 1339 deadlocks are also debuggable. 1340 1341config DEBUG_MUTEXES 1342 bool "Mutex debugging: basic checks" 1343 depends on DEBUG_KERNEL && !PREEMPT_RT 1344 help 1345 This feature allows mutex semantics violations to be detected and 1346 reported. 1347 1348config DEBUG_WW_MUTEX_SLOWPATH 1349 bool "Wait/wound mutex debugging: Slowpath testing" 1350 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1351 select DEBUG_LOCK_ALLOC 1352 select DEBUG_SPINLOCK 1353 select DEBUG_MUTEXES if !PREEMPT_RT 1354 select DEBUG_RT_MUTEXES if PREEMPT_RT 1355 help 1356 This feature enables slowpath testing for w/w mutex users by 1357 injecting additional -EDEADLK wound/backoff cases. Together with 1358 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1359 will test all possible w/w mutex interface abuse with the 1360 exception of simply not acquiring all the required locks. 1361 Note that this feature can introduce significant overhead, so 1362 it really should not be enabled in a production or distro kernel, 1363 even a debug kernel. If you are a driver writer, enable it. If 1364 you are a distro, do not. 1365 1366config DEBUG_RWSEMS 1367 bool "RW Semaphore debugging: basic checks" 1368 depends on DEBUG_KERNEL 1369 help 1370 This debugging feature allows mismatched rw semaphore locks 1371 and unlocks to be detected and reported. 1372 1373config DEBUG_LOCK_ALLOC 1374 bool "Lock debugging: detect incorrect freeing of live locks" 1375 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1376 select DEBUG_SPINLOCK 1377 select DEBUG_MUTEXES if !PREEMPT_RT 1378 select DEBUG_RT_MUTEXES if RT_MUTEXES 1379 select LOCKDEP 1380 help 1381 This feature will check whether any held lock (spinlock, rwlock, 1382 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1383 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1384 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1385 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1386 held during task exit. 1387 1388config LOCKDEP 1389 bool 1390 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1391 select STACKTRACE 1392 select KALLSYMS 1393 select KALLSYMS_ALL 1394 1395config LOCKDEP_SMALL 1396 bool 1397 1398config LOCKDEP_BITS 1399 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1400 depends on LOCKDEP && !LOCKDEP_SMALL 1401 range 10 30 1402 default 15 1403 help 1404 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1405 1406config LOCKDEP_CHAINS_BITS 1407 int "Bitsize for MAX_LOCKDEP_CHAINS" 1408 depends on LOCKDEP && !LOCKDEP_SMALL 1409 range 10 30 1410 default 16 1411 help 1412 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1413 1414config LOCKDEP_STACK_TRACE_BITS 1415 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1416 depends on LOCKDEP && !LOCKDEP_SMALL 1417 range 10 30 1418 default 19 1419 help 1420 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1421 1422config LOCKDEP_STACK_TRACE_HASH_BITS 1423 int "Bitsize for STACK_TRACE_HASH_SIZE" 1424 depends on LOCKDEP && !LOCKDEP_SMALL 1425 range 10 30 1426 default 14 1427 help 1428 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1429 1430config LOCKDEP_CIRCULAR_QUEUE_BITS 1431 int "Bitsize for elements in circular_queue struct" 1432 depends on LOCKDEP 1433 range 10 30 1434 default 12 1435 help 1436 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1437 1438config DEBUG_LOCKDEP 1439 bool "Lock dependency engine debugging" 1440 depends on DEBUG_KERNEL && LOCKDEP 1441 select DEBUG_IRQFLAGS 1442 help 1443 If you say Y here, the lock dependency engine will do 1444 additional runtime checks to debug itself, at the price 1445 of more runtime overhead. 1446 1447config DEBUG_ATOMIC_SLEEP 1448 bool "Sleep inside atomic section checking" 1449 select PREEMPT_COUNT 1450 depends on DEBUG_KERNEL 1451 depends on !ARCH_NO_PREEMPT 1452 help 1453 If you say Y here, various routines which may sleep will become very 1454 noisy if they are called inside atomic sections: when a spinlock is 1455 held, inside an rcu read side critical section, inside preempt disabled 1456 sections, inside an interrupt, etc... 1457 1458config DEBUG_LOCKING_API_SELFTESTS 1459 bool "Locking API boot-time self-tests" 1460 depends on DEBUG_KERNEL 1461 help 1462 Say Y here if you want the kernel to run a short self-test during 1463 bootup. The self-test checks whether common types of locking bugs 1464 are detected by debugging mechanisms or not. (if you disable 1465 lock debugging then those bugs won't be detected of course.) 1466 The following locking APIs are covered: spinlocks, rwlocks, 1467 mutexes and rwsems. 1468 1469config LOCK_TORTURE_TEST 1470 tristate "torture tests for locking" 1471 depends on DEBUG_KERNEL 1472 select TORTURE_TEST 1473 help 1474 This option provides a kernel module that runs torture tests 1475 on kernel locking primitives. The kernel module may be built 1476 after the fact on the running kernel to be tested, if desired. 1477 1478 Say Y here if you want kernel locking-primitive torture tests 1479 to be built into the kernel. 1480 Say M if you want these torture tests to build as a module. 1481 Say N if you are unsure. 1482 1483config WW_MUTEX_SELFTEST 1484 tristate "Wait/wound mutex selftests" 1485 help 1486 This option provides a kernel module that runs tests on the 1487 on the struct ww_mutex locking API. 1488 1489 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1490 with this test harness. 1491 1492 Say M if you want these self tests to build as a module. 1493 Say N if you are unsure. 1494 1495config SCF_TORTURE_TEST 1496 tristate "torture tests for smp_call_function*()" 1497 depends on DEBUG_KERNEL 1498 select TORTURE_TEST 1499 help 1500 This option provides a kernel module that runs torture tests 1501 on the smp_call_function() family of primitives. The kernel 1502 module may be built after the fact on the running kernel to 1503 be tested, if desired. 1504 1505config CSD_LOCK_WAIT_DEBUG 1506 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1507 depends on DEBUG_KERNEL 1508 depends on 64BIT 1509 default n 1510 help 1511 This option enables debug prints when CPUs are slow to respond 1512 to the smp_call_function*() IPI wrappers. These debug prints 1513 include the IPI handler function currently executing (if any) 1514 and relevant stack traces. 1515 1516endmenu # lock debugging 1517 1518config TRACE_IRQFLAGS 1519 depends on TRACE_IRQFLAGS_SUPPORT 1520 bool 1521 help 1522 Enables hooks to interrupt enabling and disabling for 1523 either tracing or lock debugging. 1524 1525config TRACE_IRQFLAGS_NMI 1526 def_bool y 1527 depends on TRACE_IRQFLAGS 1528 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1529 1530config DEBUG_IRQFLAGS 1531 bool "Debug IRQ flag manipulation" 1532 help 1533 Enables checks for potentially unsafe enabling or disabling of 1534 interrupts, such as calling raw_local_irq_restore() when interrupts 1535 are enabled. 1536 1537config STACKTRACE 1538 bool "Stack backtrace support" 1539 depends on STACKTRACE_SUPPORT 1540 help 1541 This option causes the kernel to create a /proc/pid/stack for 1542 every process, showing its current stack trace. 1543 It is also used by various kernel debugging features that require 1544 stack trace generation. 1545 1546config WARN_ALL_UNSEEDED_RANDOM 1547 bool "Warn for all uses of unseeded randomness" 1548 default n 1549 help 1550 Some parts of the kernel contain bugs relating to their use of 1551 cryptographically secure random numbers before it's actually possible 1552 to generate those numbers securely. This setting ensures that these 1553 flaws don't go unnoticed, by enabling a message, should this ever 1554 occur. This will allow people with obscure setups to know when things 1555 are going wrong, so that they might contact developers about fixing 1556 it. 1557 1558 Unfortunately, on some models of some architectures getting 1559 a fully seeded CRNG is extremely difficult, and so this can 1560 result in dmesg getting spammed for a surprisingly long 1561 time. This is really bad from a security perspective, and 1562 so architecture maintainers really need to do what they can 1563 to get the CRNG seeded sooner after the system is booted. 1564 However, since users cannot do anything actionable to 1565 address this, by default this option is disabled. 1566 1567 Say Y here if you want to receive warnings for all uses of 1568 unseeded randomness. This will be of use primarily for 1569 those developers interested in improving the security of 1570 Linux kernels running on their architecture (or 1571 subarchitecture). 1572 1573config DEBUG_KOBJECT 1574 bool "kobject debugging" 1575 depends on DEBUG_KERNEL 1576 help 1577 If you say Y here, some extra kobject debugging messages will be sent 1578 to the syslog. 1579 1580config DEBUG_KOBJECT_RELEASE 1581 bool "kobject release debugging" 1582 depends on DEBUG_OBJECTS_TIMERS 1583 help 1584 kobjects are reference counted objects. This means that their 1585 last reference count put is not predictable, and the kobject can 1586 live on past the point at which a driver decides to drop its 1587 initial reference to the kobject gained on allocation. An 1588 example of this would be a struct device which has just been 1589 unregistered. 1590 1591 However, some buggy drivers assume that after such an operation, 1592 the memory backing the kobject can be immediately freed. This 1593 goes completely against the principles of a refcounted object. 1594 1595 If you say Y here, the kernel will delay the release of kobjects 1596 on the last reference count to improve the visibility of this 1597 kind of kobject release bug. 1598 1599config HAVE_DEBUG_BUGVERBOSE 1600 bool 1601 1602menu "Debug kernel data structures" 1603 1604config DEBUG_LIST 1605 bool "Debug linked list manipulation" 1606 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1607 help 1608 Enable this to turn on extended checks in the linked-list 1609 walking routines. 1610 1611 If unsure, say N. 1612 1613config DEBUG_PLIST 1614 bool "Debug priority linked list manipulation" 1615 depends on DEBUG_KERNEL 1616 help 1617 Enable this to turn on extended checks in the priority-ordered 1618 linked-list (plist) walking routines. This checks the entire 1619 list multiple times during each manipulation. 1620 1621 If unsure, say N. 1622 1623config DEBUG_SG 1624 bool "Debug SG table operations" 1625 depends on DEBUG_KERNEL 1626 help 1627 Enable this to turn on checks on scatter-gather tables. This can 1628 help find problems with drivers that do not properly initialize 1629 their sg tables. 1630 1631 If unsure, say N. 1632 1633config DEBUG_NOTIFIERS 1634 bool "Debug notifier call chains" 1635 depends on DEBUG_KERNEL 1636 help 1637 Enable this to turn on sanity checking for notifier call chains. 1638 This is most useful for kernel developers to make sure that 1639 modules properly unregister themselves from notifier chains. 1640 This is a relatively cheap check but if you care about maximum 1641 performance, say N. 1642 1643config BUG_ON_DATA_CORRUPTION 1644 bool "Trigger a BUG when data corruption is detected" 1645 select DEBUG_LIST 1646 help 1647 Select this option if the kernel should BUG when it encounters 1648 data corruption in kernel memory structures when they get checked 1649 for validity. 1650 1651 If unsure, say N. 1652 1653config DEBUG_MAPLE_TREE 1654 bool "Debug maple trees" 1655 depends on DEBUG_KERNEL 1656 help 1657 Enable maple tree debugging information and extra validations. 1658 1659 If unsure, say N. 1660 1661endmenu 1662 1663config DEBUG_CREDENTIALS 1664 bool "Debug credential management" 1665 depends on DEBUG_KERNEL 1666 help 1667 Enable this to turn on some debug checking for credential 1668 management. The additional code keeps track of the number of 1669 pointers from task_structs to any given cred struct, and checks to 1670 see that this number never exceeds the usage count of the cred 1671 struct. 1672 1673 Furthermore, if SELinux is enabled, this also checks that the 1674 security pointer in the cred struct is never seen to be invalid. 1675 1676 If unsure, say N. 1677 1678source "kernel/rcu/Kconfig.debug" 1679 1680config DEBUG_WQ_FORCE_RR_CPU 1681 bool "Force round-robin CPU selection for unbound work items" 1682 depends on DEBUG_KERNEL 1683 default n 1684 help 1685 Workqueue used to implicitly guarantee that work items queued 1686 without explicit CPU specified are put on the local CPU. This 1687 guarantee is no longer true and while local CPU is still 1688 preferred work items may be put on foreign CPUs. Kernel 1689 parameter "workqueue.debug_force_rr_cpu" is added to force 1690 round-robin CPU selection to flush out usages which depend on the 1691 now broken guarantee. This config option enables the debug 1692 feature by default. When enabled, memory and cache locality will 1693 be impacted. 1694 1695config CPU_HOTPLUG_STATE_CONTROL 1696 bool "Enable CPU hotplug state control" 1697 depends on DEBUG_KERNEL 1698 depends on HOTPLUG_CPU 1699 default n 1700 help 1701 Allows to write steps between "offline" and "online" to the CPUs 1702 sysfs target file so states can be stepped granular. This is a debug 1703 option for now as the hotplug machinery cannot be stopped and 1704 restarted at arbitrary points yet. 1705 1706 Say N if your are unsure. 1707 1708config LATENCYTOP 1709 bool "Latency measuring infrastructure" 1710 depends on DEBUG_KERNEL 1711 depends on STACKTRACE_SUPPORT 1712 depends on PROC_FS 1713 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1714 select KALLSYMS 1715 select KALLSYMS_ALL 1716 select STACKTRACE 1717 select SCHEDSTATS 1718 help 1719 Enable this option if you want to use the LatencyTOP tool 1720 to find out which userspace is blocking on what kernel operations. 1721 1722config DEBUG_CGROUP_REF 1723 bool "Disable inlining of cgroup css reference count functions" 1724 depends on DEBUG_KERNEL 1725 depends on CGROUPS 1726 depends on KPROBES 1727 default n 1728 help 1729 Force cgroup css reference count functions to not be inlined so 1730 that they can be kprobed for debugging. 1731 1732source "kernel/trace/Kconfig" 1733 1734config PROVIDE_OHCI1394_DMA_INIT 1735 bool "Remote debugging over FireWire early on boot" 1736 depends on PCI && X86 1737 help 1738 If you want to debug problems which hang or crash the kernel early 1739 on boot and the crashing machine has a FireWire port, you can use 1740 this feature to remotely access the memory of the crashed machine 1741 over FireWire. This employs remote DMA as part of the OHCI1394 1742 specification which is now the standard for FireWire controllers. 1743 1744 With remote DMA, you can monitor the printk buffer remotely using 1745 firescope and access all memory below 4GB using fireproxy from gdb. 1746 Even controlling a kernel debugger is possible using remote DMA. 1747 1748 Usage: 1749 1750 If ohci1394_dma=early is used as boot parameter, it will initialize 1751 all OHCI1394 controllers which are found in the PCI config space. 1752 1753 As all changes to the FireWire bus such as enabling and disabling 1754 devices cause a bus reset and thereby disable remote DMA for all 1755 devices, be sure to have the cable plugged and FireWire enabled on 1756 the debugging host before booting the debug target for debugging. 1757 1758 This code (~1k) is freed after boot. By then, the firewire stack 1759 in charge of the OHCI-1394 controllers should be used instead. 1760 1761 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1762 1763source "samples/Kconfig" 1764 1765config ARCH_HAS_DEVMEM_IS_ALLOWED 1766 bool 1767 1768config STRICT_DEVMEM 1769 bool "Filter access to /dev/mem" 1770 depends on MMU && DEVMEM 1771 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1772 default y if PPC || X86 || ARM64 1773 help 1774 If this option is disabled, you allow userspace (root) access to all 1775 of memory, including kernel and userspace memory. Accidental 1776 access to this is obviously disastrous, but specific access can 1777 be used by people debugging the kernel. Note that with PAT support 1778 enabled, even in this case there are restrictions on /dev/mem 1779 use due to the cache aliasing requirements. 1780 1781 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1782 file only allows userspace access to PCI space and the BIOS code and 1783 data regions. This is sufficient for dosemu and X and all common 1784 users of /dev/mem. 1785 1786 If in doubt, say Y. 1787 1788config IO_STRICT_DEVMEM 1789 bool "Filter I/O access to /dev/mem" 1790 depends on STRICT_DEVMEM 1791 help 1792 If this option is disabled, you allow userspace (root) access to all 1793 io-memory regardless of whether a driver is actively using that 1794 range. Accidental access to this is obviously disastrous, but 1795 specific access can be used by people debugging kernel drivers. 1796 1797 If this option is switched on, the /dev/mem file only allows 1798 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1799 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1800 if the driver using a given range cannot be disabled. 1801 1802 If in doubt, say Y. 1803 1804menu "$(SRCARCH) Debugging" 1805 1806source "arch/$(SRCARCH)/Kconfig.debug" 1807 1808endmenu 1809 1810menu "Kernel Testing and Coverage" 1811 1812source "lib/kunit/Kconfig" 1813 1814config NOTIFIER_ERROR_INJECTION 1815 tristate "Notifier error injection" 1816 depends on DEBUG_KERNEL 1817 select DEBUG_FS 1818 help 1819 This option provides the ability to inject artificial errors to 1820 specified notifier chain callbacks. It is useful to test the error 1821 handling of notifier call chain failures. 1822 1823 Say N if unsure. 1824 1825config PM_NOTIFIER_ERROR_INJECT 1826 tristate "PM notifier error injection module" 1827 depends on PM && NOTIFIER_ERROR_INJECTION 1828 default m if PM_DEBUG 1829 help 1830 This option provides the ability to inject artificial errors to 1831 PM notifier chain callbacks. It is controlled through debugfs 1832 interface /sys/kernel/debug/notifier-error-inject/pm 1833 1834 If the notifier call chain should be failed with some events 1835 notified, write the error code to "actions/<notifier event>/error". 1836 1837 Example: Inject PM suspend error (-12 = -ENOMEM) 1838 1839 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1840 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1841 # echo mem > /sys/power/state 1842 bash: echo: write error: Cannot allocate memory 1843 1844 To compile this code as a module, choose M here: the module will 1845 be called pm-notifier-error-inject. 1846 1847 If unsure, say N. 1848 1849config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1850 tristate "OF reconfig notifier error injection module" 1851 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1852 help 1853 This option provides the ability to inject artificial errors to 1854 OF reconfig notifier chain callbacks. It is controlled 1855 through debugfs interface under 1856 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1857 1858 If the notifier call chain should be failed with some events 1859 notified, write the error code to "actions/<notifier event>/error". 1860 1861 To compile this code as a module, choose M here: the module will 1862 be called of-reconfig-notifier-error-inject. 1863 1864 If unsure, say N. 1865 1866config NETDEV_NOTIFIER_ERROR_INJECT 1867 tristate "Netdev notifier error injection module" 1868 depends on NET && NOTIFIER_ERROR_INJECTION 1869 help 1870 This option provides the ability to inject artificial errors to 1871 netdevice notifier chain callbacks. It is controlled through debugfs 1872 interface /sys/kernel/debug/notifier-error-inject/netdev 1873 1874 If the notifier call chain should be failed with some events 1875 notified, write the error code to "actions/<notifier event>/error". 1876 1877 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1878 1879 # cd /sys/kernel/debug/notifier-error-inject/netdev 1880 # echo -22 > actions/NETDEV_CHANGEMTU/error 1881 # ip link set eth0 mtu 1024 1882 RTNETLINK answers: Invalid argument 1883 1884 To compile this code as a module, choose M here: the module will 1885 be called netdev-notifier-error-inject. 1886 1887 If unsure, say N. 1888 1889config FUNCTION_ERROR_INJECTION 1890 bool "Fault-injections of functions" 1891 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1892 help 1893 Add fault injections into various functions that are annotated with 1894 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return 1895 value of theses functions. This is useful to test error paths of code. 1896 1897 If unsure, say N 1898 1899config FAULT_INJECTION 1900 bool "Fault-injection framework" 1901 depends on DEBUG_KERNEL 1902 help 1903 Provide fault-injection framework. 1904 For more details, see Documentation/fault-injection/. 1905 1906config FAILSLAB 1907 bool "Fault-injection capability for kmalloc" 1908 depends on FAULT_INJECTION 1909 depends on SLAB || SLUB 1910 help 1911 Provide fault-injection capability for kmalloc. 1912 1913config FAIL_PAGE_ALLOC 1914 bool "Fault-injection capability for alloc_pages()" 1915 depends on FAULT_INJECTION 1916 help 1917 Provide fault-injection capability for alloc_pages(). 1918 1919config FAULT_INJECTION_USERCOPY 1920 bool "Fault injection capability for usercopy functions" 1921 depends on FAULT_INJECTION 1922 help 1923 Provides fault-injection capability to inject failures 1924 in usercopy functions (copy_from_user(), get_user(), ...). 1925 1926config FAIL_MAKE_REQUEST 1927 bool "Fault-injection capability for disk IO" 1928 depends on FAULT_INJECTION && BLOCK 1929 help 1930 Provide fault-injection capability for disk IO. 1931 1932config FAIL_IO_TIMEOUT 1933 bool "Fault-injection capability for faking disk interrupts" 1934 depends on FAULT_INJECTION && BLOCK 1935 help 1936 Provide fault-injection capability on end IO handling. This 1937 will make the block layer "forget" an interrupt as configured, 1938 thus exercising the error handling. 1939 1940 Only works with drivers that use the generic timeout handling, 1941 for others it won't do anything. 1942 1943config FAIL_FUTEX 1944 bool "Fault-injection capability for futexes" 1945 select DEBUG_FS 1946 depends on FAULT_INJECTION && FUTEX 1947 help 1948 Provide fault-injection capability for futexes. 1949 1950config FAULT_INJECTION_DEBUG_FS 1951 bool "Debugfs entries for fault-injection capabilities" 1952 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1953 help 1954 Enable configuration of fault-injection capabilities via debugfs. 1955 1956config FAIL_FUNCTION 1957 bool "Fault-injection capability for functions" 1958 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1959 help 1960 Provide function-based fault-injection capability. 1961 This will allow you to override a specific function with a return 1962 with given return value. As a result, function caller will see 1963 an error value and have to handle it. This is useful to test the 1964 error handling in various subsystems. 1965 1966config FAIL_MMC_REQUEST 1967 bool "Fault-injection capability for MMC IO" 1968 depends on FAULT_INJECTION_DEBUG_FS && MMC 1969 help 1970 Provide fault-injection capability for MMC IO. 1971 This will make the mmc core return data errors. This is 1972 useful to test the error handling in the mmc block device 1973 and to test how the mmc host driver handles retries from 1974 the block device. 1975 1976config FAIL_SUNRPC 1977 bool "Fault-injection capability for SunRPC" 1978 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1979 help 1980 Provide fault-injection capability for SunRPC and 1981 its consumers. 1982 1983config FAULT_INJECTION_STACKTRACE_FILTER 1984 bool "stacktrace filter for fault-injection capabilities" 1985 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1986 select STACKTRACE 1987 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1988 help 1989 Provide stacktrace filter for fault-injection capabilities 1990 1991config ARCH_HAS_KCOV 1992 bool 1993 help 1994 An architecture should select this when it can successfully 1995 build and run with CONFIG_KCOV. This typically requires 1996 disabling instrumentation for some early boot code. 1997 1998config CC_HAS_SANCOV_TRACE_PC 1999 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 2000 2001 2002config KCOV 2003 bool "Code coverage for fuzzing" 2004 depends on ARCH_HAS_KCOV 2005 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 2006 depends on !ARCH_WANTS_NO_INSTR || HAVE_NOINSTR_HACK || \ 2007 GCC_VERSION >= 120000 || CLANG_VERSION >= 130000 2008 select DEBUG_FS 2009 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 2010 select OBJTOOL if HAVE_NOINSTR_HACK 2011 help 2012 KCOV exposes kernel code coverage information in a form suitable 2013 for coverage-guided fuzzing (randomized testing). 2014 2015 If RANDOMIZE_BASE is enabled, PC values will not be stable across 2016 different machines and across reboots. If you need stable PC values, 2017 disable RANDOMIZE_BASE. 2018 2019 For more details, see Documentation/dev-tools/kcov.rst. 2020 2021config KCOV_ENABLE_COMPARISONS 2022 bool "Enable comparison operands collection by KCOV" 2023 depends on KCOV 2024 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 2025 help 2026 KCOV also exposes operands of every comparison in the instrumented 2027 code along with operand sizes and PCs of the comparison instructions. 2028 These operands can be used by fuzzing engines to improve the quality 2029 of fuzzing coverage. 2030 2031config KCOV_INSTRUMENT_ALL 2032 bool "Instrument all code by default" 2033 depends on KCOV 2034 default y 2035 help 2036 If you are doing generic system call fuzzing (like e.g. syzkaller), 2037 then you will want to instrument the whole kernel and you should 2038 say y here. If you are doing more targeted fuzzing (like e.g. 2039 filesystem fuzzing with AFL) then you will want to enable coverage 2040 for more specific subsets of files, and should say n here. 2041 2042config KCOV_IRQ_AREA_SIZE 2043 hex "Size of interrupt coverage collection area in words" 2044 depends on KCOV 2045 default 0x40000 2046 help 2047 KCOV uses preallocated per-cpu areas to collect coverage from 2048 soft interrupts. This specifies the size of those areas in the 2049 number of unsigned long words. 2050 2051menuconfig RUNTIME_TESTING_MENU 2052 bool "Runtime Testing" 2053 def_bool y 2054 2055if RUNTIME_TESTING_MENU 2056 2057config LKDTM 2058 tristate "Linux Kernel Dump Test Tool Module" 2059 depends on DEBUG_FS 2060 help 2061 This module enables testing of the different dumping mechanisms by 2062 inducing system failures at predefined crash points. 2063 If you don't need it: say N 2064 Choose M here to compile this code as a module. The module will be 2065 called lkdtm. 2066 2067 Documentation on how to use the module can be found in 2068 Documentation/fault-injection/provoke-crashes.rst 2069 2070config CPUMASK_KUNIT_TEST 2071 tristate "KUnit test for cpumask" if !KUNIT_ALL_TESTS 2072 depends on KUNIT 2073 default KUNIT_ALL_TESTS 2074 help 2075 Enable to turn on cpumask tests, running at boot or module load time. 2076 2077 For more information on KUnit and unit tests in general, please refer 2078 to the KUnit documentation in Documentation/dev-tools/kunit/. 2079 2080 If unsure, say N. 2081 2082config TEST_LIST_SORT 2083 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2084 depends on KUNIT 2085 default KUNIT_ALL_TESTS 2086 help 2087 Enable this to turn on 'list_sort()' function test. This test is 2088 executed only once during system boot (so affects only boot time), 2089 or at module load time. 2090 2091 If unsure, say N. 2092 2093config TEST_MIN_HEAP 2094 tristate "Min heap test" 2095 depends on DEBUG_KERNEL || m 2096 help 2097 Enable this to turn on min heap function tests. This test is 2098 executed only once during system boot (so affects only boot time), 2099 or at module load time. 2100 2101 If unsure, say N. 2102 2103config TEST_SORT 2104 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2105 depends on KUNIT 2106 default KUNIT_ALL_TESTS 2107 help 2108 This option enables the self-test function of 'sort()' at boot, 2109 or at module load time. 2110 2111 If unsure, say N. 2112 2113config TEST_DIV64 2114 tristate "64bit/32bit division and modulo test" 2115 depends on DEBUG_KERNEL || m 2116 help 2117 Enable this to turn on 'do_div()' function test. This test is 2118 executed only once during system boot (so affects only boot time), 2119 or at module load time. 2120 2121 If unsure, say N. 2122 2123config KPROBES_SANITY_TEST 2124 tristate "Kprobes sanity tests" if !KUNIT_ALL_TESTS 2125 depends on DEBUG_KERNEL 2126 depends on KPROBES 2127 depends on KUNIT 2128 select STACKTRACE if ARCH_CORRECT_STACKTRACE_ON_KRETPROBE 2129 default KUNIT_ALL_TESTS 2130 help 2131 This option provides for testing basic kprobes functionality on 2132 boot. Samples of kprobe and kretprobe are inserted and 2133 verified for functionality. 2134 2135 Say N if you are unsure. 2136 2137config FPROBE_SANITY_TEST 2138 bool "Self test for fprobe" 2139 depends on DEBUG_KERNEL 2140 depends on FPROBE 2141 depends on KUNIT=y 2142 help 2143 This option will enable testing the fprobe when the system boot. 2144 A series of tests are made to verify that the fprobe is functioning 2145 properly. 2146 2147 Say N if you are unsure. 2148 2149config BACKTRACE_SELF_TEST 2150 tristate "Self test for the backtrace code" 2151 depends on DEBUG_KERNEL 2152 help 2153 This option provides a kernel module that can be used to test 2154 the kernel stack backtrace code. This option is not useful 2155 for distributions or general kernels, but only for kernel 2156 developers working on architecture code. 2157 2158 Note that if you want to also test saved backtraces, you will 2159 have to enable STACKTRACE as well. 2160 2161 Say N if you are unsure. 2162 2163config TEST_REF_TRACKER 2164 tristate "Self test for reference tracker" 2165 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT 2166 select REF_TRACKER 2167 help 2168 This option provides a kernel module performing tests 2169 using reference tracker infrastructure. 2170 2171 Say N if you are unsure. 2172 2173config RBTREE_TEST 2174 tristate "Red-Black tree test" 2175 depends on DEBUG_KERNEL 2176 help 2177 A benchmark measuring the performance of the rbtree library. 2178 Also includes rbtree invariant checks. 2179 2180config REED_SOLOMON_TEST 2181 tristate "Reed-Solomon library test" 2182 depends on DEBUG_KERNEL || m 2183 select REED_SOLOMON 2184 select REED_SOLOMON_ENC16 2185 select REED_SOLOMON_DEC16 2186 help 2187 This option enables the self-test function of rslib at boot, 2188 or at module load time. 2189 2190 If unsure, say N. 2191 2192config INTERVAL_TREE_TEST 2193 tristate "Interval tree test" 2194 depends on DEBUG_KERNEL 2195 select INTERVAL_TREE 2196 help 2197 A benchmark measuring the performance of the interval tree library 2198 2199config PERCPU_TEST 2200 tristate "Per cpu operations test" 2201 depends on m && DEBUG_KERNEL 2202 help 2203 Enable this option to build test module which validates per-cpu 2204 operations. 2205 2206 If unsure, say N. 2207 2208config ATOMIC64_SELFTEST 2209 tristate "Perform an atomic64_t self-test" 2210 help 2211 Enable this option to test the atomic64_t functions at boot or 2212 at module load time. 2213 2214 If unsure, say N. 2215 2216config ASYNC_RAID6_TEST 2217 tristate "Self test for hardware accelerated raid6 recovery" 2218 depends on ASYNC_RAID6_RECOV 2219 select ASYNC_MEMCPY 2220 help 2221 This is a one-shot self test that permutes through the 2222 recovery of all the possible two disk failure scenarios for a 2223 N-disk array. Recovery is performed with the asynchronous 2224 raid6 recovery routines, and will optionally use an offload 2225 engine if one is available. 2226 2227 If unsure, say N. 2228 2229config TEST_HEXDUMP 2230 tristate "Test functions located in the hexdump module at runtime" 2231 2232config STRING_SELFTEST 2233 tristate "Test string functions at runtime" 2234 2235config TEST_STRING_HELPERS 2236 tristate "Test functions located in the string_helpers module at runtime" 2237 2238config TEST_KSTRTOX 2239 tristate "Test kstrto*() family of functions at runtime" 2240 2241config TEST_PRINTF 2242 tristate "Test printf() family of functions at runtime" 2243 2244config TEST_SCANF 2245 tristate "Test scanf() family of functions at runtime" 2246 2247config TEST_BITMAP 2248 tristate "Test bitmap_*() family of functions at runtime" 2249 help 2250 Enable this option to test the bitmap functions at boot. 2251 2252 If unsure, say N. 2253 2254config TEST_UUID 2255 tristate "Test functions located in the uuid module at runtime" 2256 2257config TEST_XARRAY 2258 tristate "Test the XArray code at runtime" 2259 2260config TEST_MAPLE_TREE 2261 depends on DEBUG_KERNEL 2262 select DEBUG_MAPLE_TREE 2263 tristate "Test the Maple Tree code at runtime" 2264 2265config TEST_RHASHTABLE 2266 tristate "Perform selftest on resizable hash table" 2267 help 2268 Enable this option to test the rhashtable functions at boot. 2269 2270 If unsure, say N. 2271 2272config TEST_IDA 2273 tristate "Perform selftest on IDA functions" 2274 2275config TEST_PARMAN 2276 tristate "Perform selftest on priority array manager" 2277 depends on PARMAN 2278 help 2279 Enable this option to test priority array manager on boot 2280 (or module load). 2281 2282 If unsure, say N. 2283 2284config TEST_IRQ_TIMINGS 2285 bool "IRQ timings selftest" 2286 depends on IRQ_TIMINGS 2287 help 2288 Enable this option to test the irq timings code on boot. 2289 2290 If unsure, say N. 2291 2292config TEST_LKM 2293 tristate "Test module loading with 'hello world' module" 2294 depends on m 2295 help 2296 This builds the "test_module" module that emits "Hello, world" 2297 on printk when loaded. It is designed to be used for basic 2298 evaluation of the module loading subsystem (for example when 2299 validating module verification). It lacks any extra dependencies, 2300 and will not normally be loaded by the system unless explicitly 2301 requested by name. 2302 2303 If unsure, say N. 2304 2305config TEST_BITOPS 2306 tristate "Test module for compilation of bitops operations" 2307 depends on m 2308 help 2309 This builds the "test_bitops" module that is much like the 2310 TEST_LKM module except that it does a basic exercise of the 2311 set/clear_bit macros and get_count_order/long to make sure there are 2312 no compiler warnings from C=1 sparse checker or -Wextra 2313 compilations. It has no dependencies and doesn't run or load unless 2314 explicitly requested by name. for example: modprobe test_bitops. 2315 2316 If unsure, say N. 2317 2318config TEST_VMALLOC 2319 tristate "Test module for stress/performance analysis of vmalloc allocator" 2320 default n 2321 depends on MMU 2322 depends on m 2323 help 2324 This builds the "test_vmalloc" module that should be used for 2325 stress and performance analysis. So, any new change for vmalloc 2326 subsystem can be evaluated from performance and stability point 2327 of view. 2328 2329 If unsure, say N. 2330 2331config TEST_USER_COPY 2332 tristate "Test user/kernel boundary protections" 2333 depends on m 2334 help 2335 This builds the "test_user_copy" module that runs sanity checks 2336 on the copy_to/from_user infrastructure, making sure basic 2337 user/kernel boundary testing is working. If it fails to load, 2338 a regression has been detected in the user/kernel memory boundary 2339 protections. 2340 2341 If unsure, say N. 2342 2343config TEST_BPF 2344 tristate "Test BPF filter functionality" 2345 depends on m && NET 2346 help 2347 This builds the "test_bpf" module that runs various test vectors 2348 against the BPF interpreter or BPF JIT compiler depending on the 2349 current setting. This is in particular useful for BPF JIT compiler 2350 development, but also to run regression tests against changes in 2351 the interpreter code. It also enables test stubs for eBPF maps and 2352 verifier used by user space verifier testsuite. 2353 2354 If unsure, say N. 2355 2356config TEST_BLACKHOLE_DEV 2357 tristate "Test blackhole netdev functionality" 2358 depends on m && NET 2359 help 2360 This builds the "test_blackhole_dev" module that validates the 2361 data path through this blackhole netdev. 2362 2363 If unsure, say N. 2364 2365config FIND_BIT_BENCHMARK 2366 tristate "Test find_bit functions" 2367 help 2368 This builds the "test_find_bit" module that measure find_*_bit() 2369 functions performance. 2370 2371 If unsure, say N. 2372 2373config TEST_FIRMWARE 2374 tristate "Test firmware loading via userspace interface" 2375 depends on FW_LOADER 2376 help 2377 This builds the "test_firmware" module that creates a userspace 2378 interface for testing firmware loading. This can be used to 2379 control the triggering of firmware loading without needing an 2380 actual firmware-using device. The contents can be rechecked by 2381 userspace. 2382 2383 If unsure, say N. 2384 2385config TEST_SYSCTL 2386 tristate "sysctl test driver" 2387 depends on PROC_SYSCTL 2388 help 2389 This builds the "test_sysctl" module. This driver enables to test the 2390 proc sysctl interfaces available to drivers safely without affecting 2391 production knobs which might alter system functionality. 2392 2393 If unsure, say N. 2394 2395config BITFIELD_KUNIT 2396 tristate "KUnit test bitfield functions at runtime" if !KUNIT_ALL_TESTS 2397 depends on KUNIT 2398 default KUNIT_ALL_TESTS 2399 help 2400 Enable this option to test the bitfield functions at boot. 2401 2402 KUnit tests run during boot and output the results to the debug log 2403 in TAP format (http://testanything.org/). Only useful for kernel devs 2404 running the KUnit test harness, and not intended for inclusion into a 2405 production build. 2406 2407 For more information on KUnit and unit tests in general please refer 2408 to the KUnit documentation in Documentation/dev-tools/kunit/. 2409 2410 If unsure, say N. 2411 2412config HASH_KUNIT_TEST 2413 tristate "KUnit Test for integer hash functions" if !KUNIT_ALL_TESTS 2414 depends on KUNIT 2415 default KUNIT_ALL_TESTS 2416 help 2417 Enable this option to test the kernel's string (<linux/stringhash.h>), and 2418 integer (<linux/hash.h>) hash functions on boot. 2419 2420 KUnit tests run during boot and output the results to the debug log 2421 in TAP format (https://testanything.org/). Only useful for kernel devs 2422 running the KUnit test harness, and not intended for inclusion into a 2423 production build. 2424 2425 For more information on KUnit and unit tests in general please refer 2426 to the KUnit documentation in Documentation/dev-tools/kunit/. 2427 2428 This is intended to help people writing architecture-specific 2429 optimized versions. If unsure, say N. 2430 2431config RESOURCE_KUNIT_TEST 2432 tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS 2433 depends on KUNIT 2434 default KUNIT_ALL_TESTS 2435 help 2436 This builds the resource API unit test. 2437 Tests the logic of API provided by resource.c and ioport.h. 2438 For more information on KUnit and unit tests in general please refer 2439 to the KUnit documentation in Documentation/dev-tools/kunit/. 2440 2441 If unsure, say N. 2442 2443config SYSCTL_KUNIT_TEST 2444 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2445 depends on KUNIT 2446 default KUNIT_ALL_TESTS 2447 help 2448 This builds the proc sysctl unit test, which runs on boot. 2449 Tests the API contract and implementation correctness of sysctl. 2450 For more information on KUnit and unit tests in general please refer 2451 to the KUnit documentation in Documentation/dev-tools/kunit/. 2452 2453 If unsure, say N. 2454 2455config LIST_KUNIT_TEST 2456 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2457 depends on KUNIT 2458 default KUNIT_ALL_TESTS 2459 help 2460 This builds the linked list KUnit test suite. 2461 It tests that the API and basic functionality of the list_head type 2462 and associated macros. 2463 2464 KUnit tests run during boot and output the results to the debug log 2465 in TAP format (https://testanything.org/). Only useful for kernel devs 2466 running the KUnit test harness, and not intended for inclusion into a 2467 production build. 2468 2469 For more information on KUnit and unit tests in general please refer 2470 to the KUnit documentation in Documentation/dev-tools/kunit/. 2471 2472 If unsure, say N. 2473 2474config LINEAR_RANGES_TEST 2475 tristate "KUnit test for linear_ranges" 2476 depends on KUNIT 2477 select LINEAR_RANGES 2478 help 2479 This builds the linear_ranges unit test, which runs on boot. 2480 Tests the linear_ranges logic correctness. 2481 For more information on KUnit and unit tests in general please refer 2482 to the KUnit documentation in Documentation/dev-tools/kunit/. 2483 2484 If unsure, say N. 2485 2486config CMDLINE_KUNIT_TEST 2487 tristate "KUnit test for cmdline API" if !KUNIT_ALL_TESTS 2488 depends on KUNIT 2489 default KUNIT_ALL_TESTS 2490 help 2491 This builds the cmdline API unit test. 2492 Tests the logic of API provided by cmdline.c. 2493 For more information on KUnit and unit tests in general please refer 2494 to the KUnit documentation in Documentation/dev-tools/kunit/. 2495 2496 If unsure, say N. 2497 2498config BITS_TEST 2499 tristate "KUnit test for bits.h" if !KUNIT_ALL_TESTS 2500 depends on KUNIT 2501 default KUNIT_ALL_TESTS 2502 help 2503 This builds the bits unit test. 2504 Tests the logic of macros defined in bits.h. 2505 For more information on KUnit and unit tests in general please refer 2506 to the KUnit documentation in Documentation/dev-tools/kunit/. 2507 2508 If unsure, say N. 2509 2510config SLUB_KUNIT_TEST 2511 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2512 depends on SLUB_DEBUG && KUNIT 2513 default KUNIT_ALL_TESTS 2514 help 2515 This builds SLUB allocator unit test. 2516 Tests SLUB cache debugging functionality. 2517 For more information on KUnit and unit tests in general please refer 2518 to the KUnit documentation in Documentation/dev-tools/kunit/. 2519 2520 If unsure, say N. 2521 2522config RATIONAL_KUNIT_TEST 2523 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2524 depends on KUNIT && RATIONAL 2525 default KUNIT_ALL_TESTS 2526 help 2527 This builds the rational math unit test. 2528 For more information on KUnit and unit tests in general please refer 2529 to the KUnit documentation in Documentation/dev-tools/kunit/. 2530 2531 If unsure, say N. 2532 2533config MEMCPY_KUNIT_TEST 2534 tristate "Test memcpy(), memmove(), and memset() functions at runtime" if !KUNIT_ALL_TESTS 2535 depends on KUNIT 2536 default KUNIT_ALL_TESTS 2537 help 2538 Builds unit tests for memcpy(), memmove(), and memset() functions. 2539 For more information on KUnit and unit tests in general please refer 2540 to the KUnit documentation in Documentation/dev-tools/kunit/. 2541 2542 If unsure, say N. 2543 2544config IS_SIGNED_TYPE_KUNIT_TEST 2545 tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS 2546 depends on KUNIT 2547 default KUNIT_ALL_TESTS 2548 help 2549 Builds unit tests for the is_signed_type() macro. 2550 2551 For more information on KUnit and unit tests in general please refer 2552 to the KUnit documentation in Documentation/dev-tools/kunit/. 2553 2554 If unsure, say N. 2555 2556config OVERFLOW_KUNIT_TEST 2557 tristate "Test check_*_overflow() functions at runtime" if !KUNIT_ALL_TESTS 2558 depends on KUNIT 2559 default KUNIT_ALL_TESTS 2560 help 2561 Builds unit tests for the check_*_overflow(), size_*(), allocation, and 2562 related functions. 2563 2564 For more information on KUnit and unit tests in general please refer 2565 to the KUnit documentation in Documentation/dev-tools/kunit/. 2566 2567 If unsure, say N. 2568 2569config STACKINIT_KUNIT_TEST 2570 tristate "Test level of stack variable initialization" if !KUNIT_ALL_TESTS 2571 depends on KUNIT 2572 default KUNIT_ALL_TESTS 2573 help 2574 Test if the kernel is zero-initializing stack variables and 2575 padding. Coverage is controlled by compiler flags, 2576 CONFIG_INIT_STACK_ALL_PATTERN, CONFIG_INIT_STACK_ALL_ZERO, 2577 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2578 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2579 2580config FORTIFY_KUNIT_TEST 2581 tristate "Test fortified str*() and mem*() function internals at runtime" if !KUNIT_ALL_TESTS 2582 depends on KUNIT && FORTIFY_SOURCE 2583 default KUNIT_ALL_TESTS 2584 help 2585 Builds unit tests for checking internals of FORTIFY_SOURCE as used 2586 by the str*() and mem*() family of functions. For testing runtime 2587 traps of FORTIFY_SOURCE, see LKDTM's "FORTIFY_*" tests. 2588 2589config HW_BREAKPOINT_KUNIT_TEST 2590 bool "Test hw_breakpoint constraints accounting" if !KUNIT_ALL_TESTS 2591 depends on HAVE_HW_BREAKPOINT 2592 depends on KUNIT=y 2593 default KUNIT_ALL_TESTS 2594 help 2595 Tests for hw_breakpoint constraints accounting. 2596 2597 If unsure, say N. 2598 2599config STRSCPY_KUNIT_TEST 2600 tristate "Test strscpy*() family of functions at runtime" if !KUNIT_ALL_TESTS 2601 depends on KUNIT 2602 default KUNIT_ALL_TESTS 2603 2604config SIPHASH_KUNIT_TEST 2605 tristate "Perform selftest on siphash functions" if !KUNIT_ALL_TESTS 2606 depends on KUNIT 2607 default KUNIT_ALL_TESTS 2608 help 2609 Enable this option to test the kernel's siphash (<linux/siphash.h>) hash 2610 functions on boot (or module load). 2611 2612 This is intended to help people writing architecture-specific 2613 optimized versions. If unsure, say N. 2614 2615config TEST_UDELAY 2616 tristate "udelay test driver" 2617 help 2618 This builds the "udelay_test" module that helps to make sure 2619 that udelay() is working properly. 2620 2621 If unsure, say N. 2622 2623config TEST_STATIC_KEYS 2624 tristate "Test static keys" 2625 depends on m 2626 help 2627 Test the static key interfaces. 2628 2629 If unsure, say N. 2630 2631config TEST_DYNAMIC_DEBUG 2632 tristate "Test DYNAMIC_DEBUG" 2633 depends on DYNAMIC_DEBUG 2634 help 2635 This module registers a tracer callback to count enabled 2636 pr_debugs in a 'do_debugging' function, then alters their 2637 enablements, calls the function, and compares counts. 2638 2639 If unsure, say N. 2640 2641config TEST_KMOD 2642 tristate "kmod stress tester" 2643 depends on m 2644 depends on NETDEVICES && NET_CORE && INET # for TUN 2645 depends on BLOCK 2646 depends on PAGE_SIZE_LESS_THAN_256KB # for BTRFS 2647 select TEST_LKM 2648 select XFS_FS 2649 select TUN 2650 select BTRFS_FS 2651 help 2652 Test the kernel's module loading mechanism: kmod. kmod implements 2653 support to load modules using the Linux kernel's usermode helper. 2654 This test provides a series of tests against kmod. 2655 2656 Although technically you can either build test_kmod as a module or 2657 into the kernel we disallow building it into the kernel since 2658 it stress tests request_module() and this will very likely cause 2659 some issues by taking over precious threads available from other 2660 module load requests, ultimately this could be fatal. 2661 2662 To run tests run: 2663 2664 tools/testing/selftests/kmod/kmod.sh --help 2665 2666 If unsure, say N. 2667 2668config TEST_DEBUG_VIRTUAL 2669 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2670 depends on DEBUG_VIRTUAL 2671 help 2672 Test the kernel's ability to detect incorrect calls to 2673 virt_to_phys() done against the non-linear part of the 2674 kernel's virtual address map. 2675 2676 If unsure, say N. 2677 2678config TEST_MEMCAT_P 2679 tristate "Test memcat_p() helper function" 2680 help 2681 Test the memcat_p() helper for correctly merging two 2682 pointer arrays together. 2683 2684 If unsure, say N. 2685 2686config TEST_LIVEPATCH 2687 tristate "Test livepatching" 2688 default n 2689 depends on DYNAMIC_DEBUG 2690 depends on LIVEPATCH 2691 depends on m 2692 help 2693 Test kernel livepatching features for correctness. The tests will 2694 load test modules that will be livepatched in various scenarios. 2695 2696 To run all the livepatching tests: 2697 2698 make -C tools/testing/selftests TARGETS=livepatch run_tests 2699 2700 Alternatively, individual tests may be invoked: 2701 2702 tools/testing/selftests/livepatch/test-callbacks.sh 2703 tools/testing/selftests/livepatch/test-livepatch.sh 2704 tools/testing/selftests/livepatch/test-shadow-vars.sh 2705 2706 If unsure, say N. 2707 2708config TEST_OBJAGG 2709 tristate "Perform selftest on object aggreration manager" 2710 default n 2711 depends on OBJAGG 2712 help 2713 Enable this option to test object aggregation manager on boot 2714 (or module load). 2715 2716config TEST_MEMINIT 2717 tristate "Test heap/page initialization" 2718 help 2719 Test if the kernel is zero-initializing heap and page allocations. 2720 This can be useful to test init_on_alloc and init_on_free features. 2721 2722 If unsure, say N. 2723 2724config TEST_HMM 2725 tristate "Test HMM (Heterogeneous Memory Management)" 2726 depends on TRANSPARENT_HUGEPAGE 2727 depends on DEVICE_PRIVATE 2728 select HMM_MIRROR 2729 select MMU_NOTIFIER 2730 help 2731 This is a pseudo device driver solely for testing HMM. 2732 Say M here if you want to build the HMM test module. 2733 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2734 2735 If unsure, say N. 2736 2737config TEST_FREE_PAGES 2738 tristate "Test freeing pages" 2739 help 2740 Test that a memory leak does not occur due to a race between 2741 freeing a block of pages and a speculative page reference. 2742 Loading this module is safe if your kernel has the bug fixed. 2743 If the bug is not fixed, it will leak gigabytes of memory and 2744 probably OOM your system. 2745 2746config TEST_FPU 2747 tristate "Test floating point operations in kernel space" 2748 depends on X86 && !KCOV_INSTRUMENT_ALL 2749 help 2750 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2751 which will trigger a sequence of floating point operations. This is used 2752 for self-testing floating point control register setting in 2753 kernel_fpu_begin(). 2754 2755 If unsure, say N. 2756 2757config TEST_CLOCKSOURCE_WATCHDOG 2758 tristate "Test clocksource watchdog in kernel space" 2759 depends on CLOCKSOURCE_WATCHDOG 2760 help 2761 Enable this option to create a kernel module that will trigger 2762 a test of the clocksource watchdog. This module may be loaded 2763 via modprobe or insmod in which case it will run upon being 2764 loaded, or it may be built in, in which case it will run 2765 shortly after boot. 2766 2767 If unsure, say N. 2768 2769endif # RUNTIME_TESTING_MENU 2770 2771config ARCH_USE_MEMTEST 2772 bool 2773 help 2774 An architecture should select this when it uses early_memtest() 2775 during boot process. 2776 2777config MEMTEST 2778 bool "Memtest" 2779 depends on ARCH_USE_MEMTEST 2780 help 2781 This option adds a kernel parameter 'memtest', which allows memtest 2782 to be set and executed. 2783 memtest=0, mean disabled; -- default 2784 memtest=1, mean do 1 test pattern; 2785 ... 2786 memtest=17, mean do 17 test patterns. 2787 If you are unsure how to answer this question, answer N. 2788 2789 2790 2791config HYPERV_TESTING 2792 bool "Microsoft Hyper-V driver testing" 2793 default n 2794 depends on HYPERV && DEBUG_FS 2795 help 2796 Select this option to enable Hyper-V vmbus testing. 2797 2798endmenu # "Kernel Testing and Coverage" 2799 2800menu "Rust hacking" 2801 2802config RUST_DEBUG_ASSERTIONS 2803 bool "Debug assertions" 2804 depends on RUST 2805 help 2806 Enables rustc's `-Cdebug-assertions` codegen option. 2807 2808 This flag lets you turn `cfg(debug_assertions)` conditional 2809 compilation on or off. This can be used to enable extra debugging 2810 code in development but not in production. For example, it controls 2811 the behavior of the standard library's `debug_assert!` macro. 2812 2813 Note that this will apply to all Rust code, including `core`. 2814 2815 If unsure, say N. 2816 2817config RUST_OVERFLOW_CHECKS 2818 bool "Overflow checks" 2819 default y 2820 depends on RUST 2821 help 2822 Enables rustc's `-Coverflow-checks` codegen option. 2823 2824 This flag allows you to control the behavior of runtime integer 2825 overflow. When overflow-checks are enabled, a Rust panic will occur 2826 on overflow. 2827 2828 Note that this will apply to all Rust code, including `core`. 2829 2830 If unsure, say Y. 2831 2832config RUST_BUILD_ASSERT_ALLOW 2833 bool "Allow unoptimized build-time assertions" 2834 depends on RUST 2835 help 2836 Controls how are `build_error!` and `build_assert!` handled during build. 2837 2838 If calls to them exist in the binary, it may indicate a violated invariant 2839 or that the optimizer failed to verify the invariant during compilation. 2840 2841 This should not happen, thus by default the build is aborted. However, 2842 as an escape hatch, you can choose Y here to ignore them during build 2843 and let the check be carried at runtime (with `panic!` being called if 2844 the check fails). 2845 2846 If unsure, say N. 2847 2848endmenu # "Rust" 2849 2850source "Documentation/Kconfig" 2851 2852endmenu # Kernel hacking 2853