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 211menu "Compile-time checks and compiler options" 212 213config DEBUG_INFO 214 bool "Compile the kernel with debug info" 215 depends on DEBUG_KERNEL && !COMPILE_TEST 216 help 217 If you say Y here the resulting kernel image will include 218 debugging info resulting in a larger kernel image. 219 This adds debug symbols to the kernel and modules (gcc -g), and 220 is needed if you intend to use kernel crashdump or binary object 221 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 222 Say Y here only if you plan to debug the kernel. 223 224 If unsure, say N. 225 226if DEBUG_INFO 227 228config DEBUG_INFO_REDUCED 229 bool "Reduce debugging information" 230 help 231 If you say Y here gcc is instructed to generate less debugging 232 information for structure types. This means that tools that 233 need full debugging information (like kgdb or systemtap) won't 234 be happy. But if you merely need debugging information to 235 resolve line numbers there is no loss. Advantage is that 236 build directory object sizes shrink dramatically over a full 237 DEBUG_INFO build and compile times are reduced too. 238 Only works with newer gcc versions. 239 240config DEBUG_INFO_COMPRESSED 241 bool "Compressed debugging information" 242 depends on $(cc-option,-gz=zlib) 243 depends on $(ld-option,--compress-debug-sections=zlib) 244 help 245 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 246 5.0+, binutils 2.26+, and zlib. 247 248 Users of dpkg-deb via scripts/package/builddeb may find an increase in 249 size of their debug .deb packages with this config set, due to the 250 debug info being compressed with zlib, then the object files being 251 recompressed with a different compression scheme. But this is still 252 preferable to setting $KDEB_COMPRESS to "none" which would be even 253 larger. 254 255config DEBUG_INFO_SPLIT 256 bool "Produce split debuginfo in .dwo files" 257 depends on $(cc-option,-gsplit-dwarf) 258 help 259 Generate debug info into separate .dwo files. This significantly 260 reduces the build directory size for builds with DEBUG_INFO, 261 because it stores the information only once on disk in .dwo 262 files instead of multiple times in object files and executables. 263 In addition the debug information is also compressed. 264 265 Requires recent gcc (4.7+) and recent gdb/binutils. 266 Any tool that packages or reads debug information would need 267 to know about the .dwo files and include them. 268 Incompatible with older versions of ccache. 269 270choice 271 prompt "DWARF version" 272 help 273 Which version of DWARF debug info to emit. 274 275config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT 276 bool "Rely on the toolchain's implicit default DWARF version" 277 help 278 The implicit default version of DWARF debug info produced by a 279 toolchain changes over time. 280 281 This can break consumers of the debug info that haven't upgraded to 282 support newer revisions, and prevent testing newer versions, but 283 those should be less common scenarios. 284 285 If unsure, say Y. 286 287config DEBUG_INFO_DWARF4 288 bool "Generate DWARF Version 4 debuginfo" 289 help 290 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+. 291 292 If you have consumers of DWARF debug info that are not ready for 293 newer revisions of DWARF, you may wish to choose this or have your 294 config select this. 295 296config DEBUG_INFO_DWARF5 297 bool "Generate DWARF Version 5 debuginfo" 298 depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) 299 depends on !DEBUG_INFO_BTF 300 help 301 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc 302 5.0+ accepts the -gdwarf-5 flag but only had partial support for some 303 draft features until 7.0), and gdb 8.0+. 304 305 Changes to the structure of debug info in Version 5 allow for around 306 15-18% savings in resulting image and debug info section sizes as 307 compared to DWARF Version 4. DWARF Version 5 standardizes previous 308 extensions such as accelerators for symbol indexing and the format 309 for fission (.dwo/.dwp) files. Users may not want to select this 310 config if they rely on tooling that has not yet been updated to 311 support DWARF Version 5. 312 313endchoice # "DWARF version" 314 315config DEBUG_INFO_BTF 316 bool "Generate BTF typeinfo" 317 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 318 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 319 help 320 Generate deduplicated BTF type information from DWARF debug info. 321 Turning this on expects presence of pahole tool, which will convert 322 DWARF type info into equivalent deduplicated BTF type info. 323 324config PAHOLE_HAS_SPLIT_BTF 325 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119") 326 327config DEBUG_INFO_BTF_MODULES 328 def_bool y 329 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 330 help 331 Generate compact split BTF type information for kernel modules. 332 333config GDB_SCRIPTS 334 bool "Provide GDB scripts for kernel debugging" 335 help 336 This creates the required links to GDB helper scripts in the 337 build directory. If you load vmlinux into gdb, the helper 338 scripts will be automatically imported by gdb as well, and 339 additional functions are available to analyze a Linux kernel 340 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 341 for further details. 342 343endif # DEBUG_INFO 344 345config FRAME_WARN 346 int "Warn for stack frames larger than" 347 range 0 8192 348 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 349 default 1536 if (!64BIT && (PARISC || XTENSA)) 350 default 1024 if (!64BIT && !PARISC) 351 default 2048 if 64BIT 352 help 353 Tell gcc to warn at build time for stack frames larger than this. 354 Setting this too low will cause a lot of warnings. 355 Setting it to 0 disables the warning. 356 357config STRIP_ASM_SYMS 358 bool "Strip assembler-generated symbols during link" 359 default n 360 help 361 Strip internal assembler-generated symbols during a link (symbols 362 that look like '.Lxxx') so they don't pollute the output of 363 get_wchan() and suchlike. 364 365config READABLE_ASM 366 bool "Generate readable assembler code" 367 depends on DEBUG_KERNEL 368 depends on CC_IS_GCC 369 help 370 Disable some compiler optimizations that tend to generate human unreadable 371 assembler output. This may make the kernel slightly slower, but it helps 372 to keep kernel developers who have to stare a lot at assembler listings 373 sane. 374 375config HEADERS_INSTALL 376 bool "Install uapi headers to usr/include" 377 depends on !UML 378 help 379 This option will install uapi headers (headers exported to user-space) 380 into the usr/include directory for use during the kernel build. 381 This is unneeded for building the kernel itself, but needed for some 382 user-space program samples. It is also needed by some features such 383 as uapi header sanity checks. 384 385config DEBUG_SECTION_MISMATCH 386 bool "Enable full Section mismatch analysis" 387 depends on CC_IS_GCC 388 help 389 The section mismatch analysis checks if there are illegal 390 references from one section to another section. 391 During linktime or runtime, some sections are dropped; 392 any use of code/data previously in these sections would 393 most likely result in an oops. 394 In the code, functions and variables are annotated with 395 __init,, etc. (see the full list in include/linux/init.h), 396 which results in the code/data being placed in specific sections. 397 The section mismatch analysis is always performed after a full 398 kernel build, and enabling this option causes the following 399 additional step to occur: 400 - Add the option -fno-inline-functions-called-once to gcc commands. 401 When inlining a function annotated with __init in a non-init 402 function, we would lose the section information and thus 403 the analysis would not catch the illegal reference. 404 This option tells gcc to inline less (but it does result in 405 a larger kernel). 406 407config SECTION_MISMATCH_WARN_ONLY 408 bool "Make section mismatch errors non-fatal" 409 default y 410 help 411 If you say N here, the build process will fail if there are any 412 section mismatch, instead of just throwing warnings. 413 414 If unsure, say Y. 415 416config DEBUG_FORCE_FUNCTION_ALIGN_64B 417 bool "Force all function address 64B aligned" if EXPERT 418 help 419 There are cases that a commit from one domain changes the function 420 address alignment of other domains, and cause magic performance 421 bump (regression or improvement). Enable this option will help to 422 verify if the bump is caused by function alignment changes, while 423 it will slightly increase the kernel size and affect icache usage. 424 425 It is mainly for debug and performance tuning use. 426 427# 428# Select this config option from the architecture Kconfig, if it 429# is preferred to always offer frame pointers as a config 430# option on the architecture (regardless of KERNEL_DEBUG): 431# 432config ARCH_WANT_FRAME_POINTERS 433 bool 434 435config FRAME_POINTER 436 bool "Compile the kernel with frame pointers" 437 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 438 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 439 help 440 If you say Y here the resulting kernel image will be slightly 441 larger and slower, but it gives very useful debugging information 442 in case of kernel bugs. (precise oopses/stacktraces/warnings) 443 444config STACK_VALIDATION 445 bool "Compile-time stack metadata validation" 446 depends on HAVE_STACK_VALIDATION 447 default n 448 help 449 Add compile-time checks to validate stack metadata, including frame 450 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure 451 that runtime stack traces are more reliable. 452 453 This is also a prerequisite for generation of ORC unwind data, which 454 is needed for CONFIG_UNWINDER_ORC. 455 456 For more information, see 457 tools/objtool/Documentation/stack-validation.txt. 458 459config VMLINUX_VALIDATION 460 bool 461 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT 462 default y 463 464config VMLINUX_MAP 465 bool "Generate vmlinux.map file when linking" 466 depends on EXPERT 467 help 468 Selecting this option will pass "-Map=vmlinux.map" to ld 469 when linking vmlinux. That file can be useful for verifying 470 and debugging magic section games, and for seeing which 471 pieces of code get eliminated with 472 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION. 473 474config DEBUG_FORCE_WEAK_PER_CPU 475 bool "Force weak per-cpu definitions" 476 depends on DEBUG_KERNEL 477 help 478 s390 and alpha require percpu variables in modules to be 479 defined weak to work around addressing range issue which 480 puts the following two restrictions on percpu variable 481 definitions. 482 483 1. percpu symbols must be unique whether static or not 484 2. percpu variables can't be defined inside a function 485 486 To ensure that generic code follows the above rules, this 487 option forces all percpu variables to be defined as weak. 488 489endmenu # "Compiler options" 490 491menu "Generic Kernel Debugging Instruments" 492 493config MAGIC_SYSRQ 494 bool "Magic SysRq key" 495 depends on !UML 496 help 497 If you say Y here, you will have some control over the system even 498 if the system crashes for example during kernel debugging (e.g., you 499 will be able to flush the buffer cache to disk, reboot the system 500 immediately or dump some status information). This is accomplished 501 by pressing various keys while holding SysRq (Alt+PrintScreen). It 502 also works on a serial console (on PC hardware at least), if you 503 send a BREAK and then within 5 seconds a command keypress. The 504 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 505 Don't say Y unless you really know what this hack does. 506 507config MAGIC_SYSRQ_DEFAULT_ENABLE 508 hex "Enable magic SysRq key functions by default" 509 depends on MAGIC_SYSRQ 510 default 0x1 511 help 512 Specifies which SysRq key functions are enabled by default. 513 This may be set to 1 or 0 to enable or disable them all, or 514 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 515 516config MAGIC_SYSRQ_SERIAL 517 bool "Enable magic SysRq key over serial" 518 depends on MAGIC_SYSRQ 519 default y 520 help 521 Many embedded boards have a disconnected TTL level serial which can 522 generate some garbage that can lead to spurious false sysrq detects. 523 This option allows you to decide whether you want to enable the 524 magic SysRq key. 525 526config MAGIC_SYSRQ_SERIAL_SEQUENCE 527 string "Char sequence that enables magic SysRq over serial" 528 depends on MAGIC_SYSRQ_SERIAL 529 default "" 530 help 531 Specifies a sequence of characters that can follow BREAK to enable 532 SysRq on a serial console. 533 534 If unsure, leave an empty string and the option will not be enabled. 535 536config DEBUG_FS 537 bool "Debug Filesystem" 538 help 539 debugfs is a virtual file system that kernel developers use to put 540 debugging files into. Enable this option to be able to read and 541 write to these files. 542 543 For detailed documentation on the debugfs API, see 544 Documentation/filesystems/. 545 546 If unsure, say N. 547 548choice 549 prompt "Debugfs default access" 550 depends on DEBUG_FS 551 default DEBUG_FS_ALLOW_ALL 552 help 553 This selects the default access restrictions for debugfs. 554 It can be overridden with kernel command line option 555 debugfs=[on,no-mount,off]. The restrictions apply for API access 556 and filesystem registration. 557 558config DEBUG_FS_ALLOW_ALL 559 bool "Access normal" 560 help 561 No restrictions apply. Both API and filesystem registration 562 is on. This is the normal default operation. 563 564config DEBUG_FS_DISALLOW_MOUNT 565 bool "Do not register debugfs as filesystem" 566 help 567 The API is open but filesystem is not loaded. Clients can still do 568 their work and read with debug tools that do not need 569 debugfs filesystem. 570 571config DEBUG_FS_ALLOW_NONE 572 bool "No access" 573 help 574 Access is off. Clients get -PERM when trying to create nodes in 575 debugfs tree and debugfs is not registered as a filesystem. 576 Client can then back-off or continue without debugfs access. 577 578endchoice 579 580source "lib/Kconfig.kgdb" 581source "lib/Kconfig.ubsan" 582source "lib/Kconfig.kcsan" 583 584endmenu 585 586config DEBUG_KERNEL 587 bool "Kernel debugging" 588 help 589 Say Y here if you are developing drivers or trying to debug and 590 identify kernel problems. 591 592config DEBUG_MISC 593 bool "Miscellaneous debug code" 594 default DEBUG_KERNEL 595 depends on DEBUG_KERNEL 596 help 597 Say Y here if you need to enable miscellaneous debug code that should 598 be under a more specific debug option but isn't. 599 600 601menu "Memory Debugging" 602 603source "mm/Kconfig.debug" 604 605config DEBUG_OBJECTS 606 bool "Debug object operations" 607 depends on DEBUG_KERNEL 608 help 609 If you say Y here, additional code will be inserted into the 610 kernel to track the life time of various objects and validate 611 the operations on those objects. 612 613config DEBUG_OBJECTS_SELFTEST 614 bool "Debug objects selftest" 615 depends on DEBUG_OBJECTS 616 help 617 This enables the selftest of the object debug code. 618 619config DEBUG_OBJECTS_FREE 620 bool "Debug objects in freed memory" 621 depends on DEBUG_OBJECTS 622 help 623 This enables checks whether a k/v free operation frees an area 624 which contains an object which has not been deactivated 625 properly. This can make kmalloc/kfree-intensive workloads 626 much slower. 627 628config DEBUG_OBJECTS_TIMERS 629 bool "Debug timer objects" 630 depends on DEBUG_OBJECTS 631 help 632 If you say Y here, additional code will be inserted into the 633 timer routines to track the life time of timer objects and 634 validate the timer operations. 635 636config DEBUG_OBJECTS_WORK 637 bool "Debug work objects" 638 depends on DEBUG_OBJECTS 639 help 640 If you say Y here, additional code will be inserted into the 641 work queue routines to track the life time of work objects and 642 validate the work operations. 643 644config DEBUG_OBJECTS_RCU_HEAD 645 bool "Debug RCU callbacks objects" 646 depends on DEBUG_OBJECTS 647 help 648 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 649 650config DEBUG_OBJECTS_PERCPU_COUNTER 651 bool "Debug percpu counter objects" 652 depends on DEBUG_OBJECTS 653 help 654 If you say Y here, additional code will be inserted into the 655 percpu counter routines to track the life time of percpu counter 656 objects and validate the percpu counter operations. 657 658config DEBUG_OBJECTS_ENABLE_DEFAULT 659 int "debug_objects bootup default value (0-1)" 660 range 0 1 661 default "1" 662 depends on DEBUG_OBJECTS 663 help 664 Debug objects boot parameter default value 665 666config DEBUG_SLAB 667 bool "Debug slab memory allocations" 668 depends on DEBUG_KERNEL && SLAB 669 help 670 Say Y here to have the kernel do limited verification on memory 671 allocation as well as poisoning memory on free to catch use of freed 672 memory. This can make kmalloc/kfree-intensive workloads much slower. 673 674config SLUB_DEBUG_ON 675 bool "SLUB debugging on by default" 676 depends on SLUB && SLUB_DEBUG 677 default n 678 help 679 Boot with debugging on by default. SLUB boots by default with 680 the runtime debug capabilities switched off. Enabling this is 681 equivalent to specifying the "slub_debug" parameter on boot. 682 There is no support for more fine grained debug control like 683 possible with slub_debug=xxx. SLUB debugging may be switched 684 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 685 "slub_debug=-". 686 687config SLUB_STATS 688 default n 689 bool "Enable SLUB performance statistics" 690 depends on SLUB && SYSFS 691 help 692 SLUB statistics are useful to debug SLUBs allocation behavior in 693 order find ways to optimize the allocator. This should never be 694 enabled for production use since keeping statistics slows down 695 the allocator by a few percentage points. The slabinfo command 696 supports the determination of the most active slabs to figure 697 out which slabs are relevant to a particular load. 698 Try running: slabinfo -DA 699 700config HAVE_DEBUG_KMEMLEAK 701 bool 702 703config DEBUG_KMEMLEAK 704 bool "Kernel memory leak detector" 705 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 706 select DEBUG_FS 707 select STACKTRACE if STACKTRACE_SUPPORT 708 select KALLSYMS 709 select CRC32 710 help 711 Say Y here if you want to enable the memory leak 712 detector. The memory allocation/freeing is traced in a way 713 similar to the Boehm's conservative garbage collector, the 714 difference being that the orphan objects are not freed but 715 only shown in /sys/kernel/debug/kmemleak. Enabling this 716 feature will introduce an overhead to memory 717 allocations. See Documentation/dev-tools/kmemleak.rst for more 718 details. 719 720 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 721 of finding leaks due to the slab objects poisoning. 722 723 In order to access the kmemleak file, debugfs needs to be 724 mounted (usually at /sys/kernel/debug). 725 726config DEBUG_KMEMLEAK_MEM_POOL_SIZE 727 int "Kmemleak memory pool size" 728 depends on DEBUG_KMEMLEAK 729 range 200 1000000 730 default 16000 731 help 732 Kmemleak must track all the memory allocations to avoid 733 reporting false positives. Since memory may be allocated or 734 freed before kmemleak is fully initialised, use a static pool 735 of metadata objects to track such callbacks. After kmemleak is 736 fully initialised, this memory pool acts as an emergency one 737 if slab allocations fail. 738 739config DEBUG_KMEMLEAK_TEST 740 tristate "Simple test for the kernel memory leak detector" 741 depends on DEBUG_KMEMLEAK && m 742 help 743 This option enables a module that explicitly leaks memory. 744 745 If unsure, say N. 746 747config DEBUG_KMEMLEAK_DEFAULT_OFF 748 bool "Default kmemleak to off" 749 depends on DEBUG_KMEMLEAK 750 help 751 Say Y here to disable kmemleak by default. It can then be enabled 752 on the command line via kmemleak=on. 753 754config DEBUG_KMEMLEAK_AUTO_SCAN 755 bool "Enable kmemleak auto scan thread on boot up" 756 default y 757 depends on DEBUG_KMEMLEAK 758 help 759 Depending on the cpu, kmemleak scan may be cpu intensive and can 760 stall user tasks at times. This option enables/disables automatic 761 kmemleak scan at boot up. 762 763 Say N here to disable kmemleak auto scan thread to stop automatic 764 scanning. Disabling this option disables automatic reporting of 765 memory leaks. 766 767 If unsure, say Y. 768 769config DEBUG_STACK_USAGE 770 bool "Stack utilization instrumentation" 771 depends on DEBUG_KERNEL && !IA64 772 help 773 Enables the display of the minimum amount of free stack which each 774 task has ever had available in the sysrq-T and sysrq-P debug output. 775 776 This option will slow down process creation somewhat. 777 778config SCHED_STACK_END_CHECK 779 bool "Detect stack corruption on calls to schedule()" 780 depends on DEBUG_KERNEL 781 default n 782 help 783 This option checks for a stack overrun on calls to schedule(). 784 If the stack end location is found to be over written always panic as 785 the content of the corrupted region can no longer be trusted. 786 This is to ensure no erroneous behaviour occurs which could result in 787 data corruption or a sporadic crash at a later stage once the region 788 is examined. The runtime overhead introduced is minimal. 789 790config ARCH_HAS_DEBUG_VM_PGTABLE 791 bool 792 help 793 An architecture should select this when it can successfully 794 build and run DEBUG_VM_PGTABLE. 795 796config DEBUG_VM 797 bool "Debug VM" 798 depends on DEBUG_KERNEL 799 help 800 Enable this to turn on extended checks in the virtual-memory system 801 that may impact performance. 802 803 If unsure, say N. 804 805config DEBUG_VM_VMACACHE 806 bool "Debug VMA caching" 807 depends on DEBUG_VM 808 help 809 Enable this to turn on VMA caching debug information. Doing so 810 can cause significant overhead, so only enable it in non-production 811 environments. 812 813 If unsure, say N. 814 815config DEBUG_VM_RB 816 bool "Debug VM red-black trees" 817 depends on DEBUG_VM 818 help 819 Enable VM red-black tree debugging information and extra validations. 820 821 If unsure, say N. 822 823config DEBUG_VM_PGFLAGS 824 bool "Debug page-flags operations" 825 depends on DEBUG_VM 826 help 827 Enables extra validation on page flags operations. 828 829 If unsure, say N. 830 831config DEBUG_VM_PGTABLE 832 bool "Debug arch page table for semantics compliance" 833 depends on MMU 834 depends on ARCH_HAS_DEBUG_VM_PGTABLE 835 default y if DEBUG_VM 836 help 837 This option provides a debug method which can be used to test 838 architecture page table helper functions on various platforms in 839 verifying if they comply with expected generic MM semantics. This 840 will help architecture code in making sure that any changes or 841 new additions of these helpers still conform to expected 842 semantics of the generic MM. Platforms will have to opt in for 843 this through ARCH_HAS_DEBUG_VM_PGTABLE. 844 845 If unsure, say N. 846 847config ARCH_HAS_DEBUG_VIRTUAL 848 bool 849 850config DEBUG_VIRTUAL 851 bool "Debug VM translations" 852 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 853 help 854 Enable some costly sanity checks in virtual to page code. This can 855 catch mistakes with virt_to_page() and friends. 856 857 If unsure, say N. 858 859config DEBUG_NOMMU_REGIONS 860 bool "Debug the global anon/private NOMMU mapping region tree" 861 depends on DEBUG_KERNEL && !MMU 862 help 863 This option causes the global tree of anonymous and private mapping 864 regions to be regularly checked for invalid topology. 865 866config DEBUG_MEMORY_INIT 867 bool "Debug memory initialisation" if EXPERT 868 default !EXPERT 869 help 870 Enable this for additional checks during memory initialisation. 871 The sanity checks verify aspects of the VM such as the memory model 872 and other information provided by the architecture. Verbose 873 information will be printed at KERN_DEBUG loglevel depending 874 on the mminit_loglevel= command-line option. 875 876 If unsure, say Y 877 878config MEMORY_NOTIFIER_ERROR_INJECT 879 tristate "Memory hotplug notifier error injection module" 880 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION 881 help 882 This option provides the ability to inject artificial errors to 883 memory hotplug notifier chain callbacks. It is controlled through 884 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 885 886 If the notifier call chain should be failed with some events 887 notified, write the error code to "actions/<notifier event>/error". 888 889 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 890 891 # cd /sys/kernel/debug/notifier-error-inject/memory 892 # echo -12 > actions/MEM_GOING_OFFLINE/error 893 # echo offline > /sys/devices/system/memory/memoryXXX/state 894 bash: echo: write error: Cannot allocate memory 895 896 To compile this code as a module, choose M here: the module will 897 be called memory-notifier-error-inject. 898 899 If unsure, say N. 900 901config DEBUG_PER_CPU_MAPS 902 bool "Debug access to per_cpu maps" 903 depends on DEBUG_KERNEL 904 depends on SMP 905 help 906 Say Y to verify that the per_cpu map being accessed has 907 been set up. This adds a fair amount of code to kernel memory 908 and decreases performance. 909 910 Say N if unsure. 911 912config DEBUG_KMAP_LOCAL 913 bool "Debug kmap_local temporary mappings" 914 depends on DEBUG_KERNEL && KMAP_LOCAL 915 help 916 This option enables additional error checking for the kmap_local 917 infrastructure. Disable for production use. 918 919config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 920 bool 921 922config DEBUG_KMAP_LOCAL_FORCE_MAP 923 bool "Enforce kmap_local temporary mappings" 924 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 925 select KMAP_LOCAL 926 select DEBUG_KMAP_LOCAL 927 help 928 This option enforces temporary mappings through the kmap_local 929 mechanism for non-highmem pages and on non-highmem systems. 930 Disable this for production systems! 931 932config DEBUG_HIGHMEM 933 bool "Highmem debugging" 934 depends on DEBUG_KERNEL && HIGHMEM 935 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP 936 select DEBUG_KMAP_LOCAL 937 help 938 This option enables additional error checking for high memory 939 systems. Disable for production systems. 940 941config HAVE_DEBUG_STACKOVERFLOW 942 bool 943 944config DEBUG_STACKOVERFLOW 945 bool "Check for stack overflows" 946 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 947 help 948 Say Y here if you want to check for overflows of kernel, IRQ 949 and exception stacks (if your architecture uses them). This 950 option will show detailed messages if free stack space drops 951 below a certain limit. 952 953 These kinds of bugs usually occur when call-chains in the 954 kernel get too deep, especially when interrupts are 955 involved. 956 957 Use this in cases where you see apparently random memory 958 corruption, especially if it appears in 'struct thread_info' 959 960 If in doubt, say "N". 961 962source "lib/Kconfig.kasan" 963source "lib/Kconfig.kfence" 964 965endmenu # "Memory Debugging" 966 967config DEBUG_SHIRQ 968 bool "Debug shared IRQ handlers" 969 depends on DEBUG_KERNEL 970 help 971 Enable this to generate a spurious interrupt just before a shared 972 interrupt handler is deregistered (generating one when registering 973 is currently disabled). Drivers need to handle this correctly. Some 974 don't and need to be caught. 975 976menu "Debug Oops, Lockups and Hangs" 977 978config PANIC_ON_OOPS 979 bool "Panic on Oops" 980 help 981 Say Y here to enable the kernel to panic when it oopses. This 982 has the same effect as setting oops=panic on the kernel command 983 line. 984 985 This feature is useful to ensure that the kernel does not do 986 anything erroneous after an oops which could result in data 987 corruption or other issues. 988 989 Say N if unsure. 990 991config PANIC_ON_OOPS_VALUE 992 int 993 range 0 1 994 default 0 if !PANIC_ON_OOPS 995 default 1 if PANIC_ON_OOPS 996 997config PANIC_TIMEOUT 998 int "panic timeout" 999 default 0 1000 help 1001 Set the timeout value (in seconds) until a reboot occurs when 1002 the kernel panics. If n = 0, then we wait forever. A timeout 1003 value n > 0 will wait n seconds before rebooting, while a timeout 1004 value n < 0 will reboot immediately. 1005 1006config LOCKUP_DETECTOR 1007 bool 1008 1009config SOFTLOCKUP_DETECTOR 1010 bool "Detect Soft Lockups" 1011 depends on DEBUG_KERNEL && !S390 1012 select LOCKUP_DETECTOR 1013 help 1014 Say Y here to enable the kernel to act as a watchdog to detect 1015 soft lockups. 1016 1017 Softlockups are bugs that cause the kernel to loop in kernel 1018 mode for more than 20 seconds, without giving other tasks a 1019 chance to run. The current stack trace is displayed upon 1020 detection and the system will stay locked up. 1021 1022config BOOTPARAM_SOFTLOCKUP_PANIC 1023 bool "Panic (Reboot) On Soft Lockups" 1024 depends on SOFTLOCKUP_DETECTOR 1025 help 1026 Say Y here to enable the kernel to panic on "soft lockups", 1027 which are bugs that cause the kernel to loop in kernel 1028 mode for more than 20 seconds (configurable using the watchdog_thresh 1029 sysctl), without giving other tasks a chance to run. 1030 1031 The panic can be used in combination with panic_timeout, 1032 to cause the system to reboot automatically after a 1033 lockup has been detected. This feature is useful for 1034 high-availability systems that have uptime guarantees and 1035 where a lockup must be resolved ASAP. 1036 1037 Say N if unsure. 1038 1039config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 1040 int 1041 depends on SOFTLOCKUP_DETECTOR 1042 range 0 1 1043 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 1044 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 1045 1046config HARDLOCKUP_DETECTOR_PERF 1047 bool 1048 select SOFTLOCKUP_DETECTOR 1049 1050# 1051# Enables a timestamp based low pass filter to compensate for perf based 1052# hard lockup detection which runs too fast due to turbo modes. 1053# 1054config HARDLOCKUP_CHECK_TIMESTAMP 1055 bool 1056 1057# 1058# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 1059# lockup detector rather than the perf based detector. 1060# 1061config HARDLOCKUP_DETECTOR 1062 bool "Detect Hard Lockups" 1063 depends on DEBUG_KERNEL && !S390 1064 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 1065 select LOCKUP_DETECTOR 1066 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 1067 help 1068 Say Y here to enable the kernel to act as a watchdog to detect 1069 hard lockups. 1070 1071 Hardlockups are bugs that cause the CPU to loop in kernel mode 1072 for more than 10 seconds, without letting other interrupts have a 1073 chance to run. The current stack trace is displayed upon detection 1074 and the system will stay locked up. 1075 1076config BOOTPARAM_HARDLOCKUP_PANIC 1077 bool "Panic (Reboot) On Hard Lockups" 1078 depends on HARDLOCKUP_DETECTOR 1079 help 1080 Say Y here to enable the kernel to panic on "hard lockups", 1081 which are bugs that cause the kernel to loop in kernel 1082 mode with interrupts disabled for more than 10 seconds (configurable 1083 using the watchdog_thresh sysctl). 1084 1085 Say N if unsure. 1086 1087config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1088 int 1089 depends on HARDLOCKUP_DETECTOR 1090 range 0 1 1091 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1092 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1093 1094config DETECT_HUNG_TASK 1095 bool "Detect Hung Tasks" 1096 depends on DEBUG_KERNEL 1097 default SOFTLOCKUP_DETECTOR 1098 help 1099 Say Y here to enable the kernel to detect "hung tasks", 1100 which are bugs that cause the task to be stuck in 1101 uninterruptible "D" state indefinitely. 1102 1103 When a hung task is detected, the kernel will print the 1104 current stack trace (which you should report), but the 1105 task will stay in uninterruptible state. If lockdep is 1106 enabled then all held locks will also be reported. This 1107 feature has negligible overhead. 1108 1109config DEFAULT_HUNG_TASK_TIMEOUT 1110 int "Default timeout for hung task detection (in seconds)" 1111 depends on DETECT_HUNG_TASK 1112 default 120 1113 help 1114 This option controls the default timeout (in seconds) used 1115 to determine when a task has become non-responsive and should 1116 be considered hung. 1117 1118 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1119 sysctl or by writing a value to 1120 /proc/sys/kernel/hung_task_timeout_secs. 1121 1122 A timeout of 0 disables the check. The default is two minutes. 1123 Keeping the default should be fine in most cases. 1124 1125config BOOTPARAM_HUNG_TASK_PANIC 1126 bool "Panic (Reboot) On Hung Tasks" 1127 depends on DETECT_HUNG_TASK 1128 help 1129 Say Y here to enable the kernel to panic on "hung tasks", 1130 which are bugs that cause the kernel to leave a task stuck 1131 in uninterruptible "D" state. 1132 1133 The panic can be used in combination with panic_timeout, 1134 to cause the system to reboot automatically after a 1135 hung task has been detected. This feature is useful for 1136 high-availability systems that have uptime guarantees and 1137 where a hung tasks must be resolved ASAP. 1138 1139 Say N if unsure. 1140 1141config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1142 int 1143 depends on DETECT_HUNG_TASK 1144 range 0 1 1145 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1146 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1147 1148config WQ_WATCHDOG 1149 bool "Detect Workqueue Stalls" 1150 depends on DEBUG_KERNEL 1151 help 1152 Say Y here to enable stall detection on workqueues. If a 1153 worker pool doesn't make forward progress on a pending work 1154 item for over a given amount of time, 30s by default, a 1155 warning message is printed along with dump of workqueue 1156 state. This can be configured through kernel parameter 1157 "workqueue.watchdog_thresh" and its sysfs counterpart. 1158 1159config TEST_LOCKUP 1160 tristate "Test module to generate lockups" 1161 depends on m 1162 help 1163 This builds the "test_lockup" module that helps to make sure 1164 that watchdogs and lockup detectors are working properly. 1165 1166 Depending on module parameters it could emulate soft or hard 1167 lockup, "hung task", or locking arbitrary lock for a long time. 1168 Also it could generate series of lockups with cooling-down periods. 1169 1170 If unsure, say N. 1171 1172endmenu # "Debug lockups and hangs" 1173 1174menu "Scheduler Debugging" 1175 1176config SCHED_DEBUG 1177 bool "Collect scheduler debugging info" 1178 depends on DEBUG_KERNEL && PROC_FS 1179 default y 1180 help 1181 If you say Y here, the /proc/sched_debug file will be provided 1182 that can help debug the scheduler. The runtime overhead of this 1183 option is minimal. 1184 1185config SCHED_INFO 1186 bool 1187 default n 1188 1189config SCHEDSTATS 1190 bool "Collect scheduler statistics" 1191 depends on DEBUG_KERNEL && PROC_FS 1192 select SCHED_INFO 1193 help 1194 If you say Y here, additional code will be inserted into the 1195 scheduler and related routines to collect statistics about 1196 scheduler behavior and provide them in /proc/schedstat. These 1197 stats may be useful for both tuning and debugging the scheduler 1198 If you aren't debugging the scheduler or trying to tune a specific 1199 application, you can say N to avoid the very slight overhead 1200 this adds. 1201 1202endmenu 1203 1204config DEBUG_TIMEKEEPING 1205 bool "Enable extra timekeeping sanity checking" 1206 help 1207 This option will enable additional timekeeping sanity checks 1208 which may be helpful when diagnosing issues where timekeeping 1209 problems are suspected. 1210 1211 This may include checks in the timekeeping hotpaths, so this 1212 option may have a (very small) performance impact to some 1213 workloads. 1214 1215 If unsure, say N. 1216 1217config DEBUG_PREEMPT 1218 bool "Debug preemptible kernel" 1219 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1220 default y 1221 help 1222 If you say Y here then the kernel will use a debug variant of the 1223 commonly used smp_processor_id() function and will print warnings 1224 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1225 will detect preemption count underflows. 1226 1227menu "Lock Debugging (spinlocks, mutexes, etc...)" 1228 1229config LOCK_DEBUGGING_SUPPORT 1230 bool 1231 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1232 default y 1233 1234config PROVE_LOCKING 1235 bool "Lock debugging: prove locking correctness" 1236 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1237 select LOCKDEP 1238 select DEBUG_SPINLOCK 1239 select DEBUG_MUTEXES if !PREEMPT_RT 1240 select DEBUG_RT_MUTEXES if RT_MUTEXES 1241 select DEBUG_RWSEMS 1242 select DEBUG_WW_MUTEX_SLOWPATH 1243 select DEBUG_LOCK_ALLOC 1244 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1245 select TRACE_IRQFLAGS 1246 default n 1247 help 1248 This feature enables the kernel to prove that all locking 1249 that occurs in the kernel runtime is mathematically 1250 correct: that under no circumstance could an arbitrary (and 1251 not yet triggered) combination of observed locking 1252 sequences (on an arbitrary number of CPUs, running an 1253 arbitrary number of tasks and interrupt contexts) cause a 1254 deadlock. 1255 1256 In short, this feature enables the kernel to report locking 1257 related deadlocks before they actually occur. 1258 1259 The proof does not depend on how hard and complex a 1260 deadlock scenario would be to trigger: how many 1261 participant CPUs, tasks and irq-contexts would be needed 1262 for it to trigger. The proof also does not depend on 1263 timing: if a race and a resulting deadlock is possible 1264 theoretically (no matter how unlikely the race scenario 1265 is), it will be proven so and will immediately be 1266 reported by the kernel (once the event is observed that 1267 makes the deadlock theoretically possible). 1268 1269 If a deadlock is impossible (i.e. the locking rules, as 1270 observed by the kernel, are mathematically correct), the 1271 kernel reports nothing. 1272 1273 NOTE: this feature can also be enabled for rwlocks, mutexes 1274 and rwsems - in which case all dependencies between these 1275 different locking variants are observed and mapped too, and 1276 the proof of observed correctness is also maintained for an 1277 arbitrary combination of these separate locking variants. 1278 1279 For more details, see Documentation/locking/lockdep-design.rst. 1280 1281config PROVE_RAW_LOCK_NESTING 1282 bool "Enable raw_spinlock - spinlock nesting checks" 1283 depends on PROVE_LOCKING 1284 default n 1285 help 1286 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1287 that the lock nesting rules for PREEMPT_RT enabled kernels are 1288 not violated. 1289 1290 NOTE: There are known nesting problems. So if you enable this 1291 option expect lockdep splats until these problems have been fully 1292 addressed which is work in progress. This config switch allows to 1293 identify and analyze these problems. It will be removed and the 1294 check permanently enabled once the main issues have been fixed. 1295 1296 If unsure, select N. 1297 1298config LOCK_STAT 1299 bool "Lock usage statistics" 1300 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1301 select LOCKDEP 1302 select DEBUG_SPINLOCK 1303 select DEBUG_MUTEXES if !PREEMPT_RT 1304 select DEBUG_RT_MUTEXES if RT_MUTEXES 1305 select DEBUG_LOCK_ALLOC 1306 default n 1307 help 1308 This feature enables tracking lock contention points 1309 1310 For more details, see Documentation/locking/lockstat.rst 1311 1312 This also enables lock events required by "perf lock", 1313 subcommand of perf. 1314 If you want to use "perf lock", you also need to turn on 1315 CONFIG_EVENT_TRACING. 1316 1317 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1318 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1319 1320config DEBUG_RT_MUTEXES 1321 bool "RT Mutex debugging, deadlock detection" 1322 depends on DEBUG_KERNEL && RT_MUTEXES 1323 help 1324 This allows rt mutex semantics violations and rt mutex related 1325 deadlocks (lockups) to be detected and reported automatically. 1326 1327config DEBUG_SPINLOCK 1328 bool "Spinlock and rw-lock debugging: basic checks" 1329 depends on DEBUG_KERNEL 1330 select UNINLINE_SPIN_UNLOCK 1331 help 1332 Say Y here and build SMP to catch missing spinlock initialization 1333 and certain other kinds of spinlock errors commonly made. This is 1334 best used in conjunction with the NMI watchdog so that spinlock 1335 deadlocks are also debuggable. 1336 1337config DEBUG_MUTEXES 1338 bool "Mutex debugging: basic checks" 1339 depends on DEBUG_KERNEL && !PREEMPT_RT 1340 help 1341 This feature allows mutex semantics violations to be detected and 1342 reported. 1343 1344config DEBUG_WW_MUTEX_SLOWPATH 1345 bool "Wait/wound mutex debugging: Slowpath testing" 1346 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1347 select DEBUG_LOCK_ALLOC 1348 select DEBUG_SPINLOCK 1349 select DEBUG_MUTEXES if !PREEMPT_RT 1350 select DEBUG_RT_MUTEXES if PREEMPT_RT 1351 help 1352 This feature enables slowpath testing for w/w mutex users by 1353 injecting additional -EDEADLK wound/backoff cases. Together with 1354 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1355 will test all possible w/w mutex interface abuse with the 1356 exception of simply not acquiring all the required locks. 1357 Note that this feature can introduce significant overhead, so 1358 it really should not be enabled in a production or distro kernel, 1359 even a debug kernel. If you are a driver writer, enable it. If 1360 you are a distro, do not. 1361 1362config DEBUG_RWSEMS 1363 bool "RW Semaphore debugging: basic checks" 1364 depends on DEBUG_KERNEL 1365 help 1366 This debugging feature allows mismatched rw semaphore locks 1367 and unlocks to be detected and reported. 1368 1369config DEBUG_LOCK_ALLOC 1370 bool "Lock debugging: detect incorrect freeing of live locks" 1371 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1372 select DEBUG_SPINLOCK 1373 select DEBUG_MUTEXES if !PREEMPT_RT 1374 select DEBUG_RT_MUTEXES if RT_MUTEXES 1375 select LOCKDEP 1376 help 1377 This feature will check whether any held lock (spinlock, rwlock, 1378 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1379 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1380 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1381 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1382 held during task exit. 1383 1384config LOCKDEP 1385 bool 1386 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1387 select STACKTRACE 1388 select KALLSYMS 1389 select KALLSYMS_ALL 1390 1391config LOCKDEP_SMALL 1392 bool 1393 1394config LOCKDEP_BITS 1395 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1396 depends on LOCKDEP && !LOCKDEP_SMALL 1397 range 10 30 1398 default 15 1399 help 1400 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1401 1402config LOCKDEP_CHAINS_BITS 1403 int "Bitsize for MAX_LOCKDEP_CHAINS" 1404 depends on LOCKDEP && !LOCKDEP_SMALL 1405 range 10 30 1406 default 16 1407 help 1408 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1409 1410config LOCKDEP_STACK_TRACE_BITS 1411 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1412 depends on LOCKDEP && !LOCKDEP_SMALL 1413 range 10 30 1414 default 19 1415 help 1416 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1417 1418config LOCKDEP_STACK_TRACE_HASH_BITS 1419 int "Bitsize for STACK_TRACE_HASH_SIZE" 1420 depends on LOCKDEP && !LOCKDEP_SMALL 1421 range 10 30 1422 default 14 1423 help 1424 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1425 1426config LOCKDEP_CIRCULAR_QUEUE_BITS 1427 int "Bitsize for elements in circular_queue struct" 1428 depends on LOCKDEP 1429 range 10 30 1430 default 12 1431 help 1432 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1433 1434config DEBUG_LOCKDEP 1435 bool "Lock dependency engine debugging" 1436 depends on DEBUG_KERNEL && LOCKDEP 1437 select DEBUG_IRQFLAGS 1438 help 1439 If you say Y here, the lock dependency engine will do 1440 additional runtime checks to debug itself, at the price 1441 of more runtime overhead. 1442 1443config DEBUG_ATOMIC_SLEEP 1444 bool "Sleep inside atomic section checking" 1445 select PREEMPT_COUNT 1446 depends on DEBUG_KERNEL 1447 depends on !ARCH_NO_PREEMPT 1448 help 1449 If you say Y here, various routines which may sleep will become very 1450 noisy if they are called inside atomic sections: when a spinlock is 1451 held, inside an rcu read side critical section, inside preempt disabled 1452 sections, inside an interrupt, etc... 1453 1454config DEBUG_LOCKING_API_SELFTESTS 1455 bool "Locking API boot-time self-tests" 1456 depends on DEBUG_KERNEL 1457 help 1458 Say Y here if you want the kernel to run a short self-test during 1459 bootup. The self-test checks whether common types of locking bugs 1460 are detected by debugging mechanisms or not. (if you disable 1461 lock debugging then those bugs won't be detected of course.) 1462 The following locking APIs are covered: spinlocks, rwlocks, 1463 mutexes and rwsems. 1464 1465config LOCK_TORTURE_TEST 1466 tristate "torture tests for locking" 1467 depends on DEBUG_KERNEL 1468 select TORTURE_TEST 1469 help 1470 This option provides a kernel module that runs torture tests 1471 on kernel locking primitives. The kernel module may be built 1472 after the fact on the running kernel to be tested, if desired. 1473 1474 Say Y here if you want kernel locking-primitive torture tests 1475 to be built into the kernel. 1476 Say M if you want these torture tests to build as a module. 1477 Say N if you are unsure. 1478 1479config WW_MUTEX_SELFTEST 1480 tristate "Wait/wound mutex selftests" 1481 help 1482 This option provides a kernel module that runs tests on the 1483 on the struct ww_mutex locking API. 1484 1485 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1486 with this test harness. 1487 1488 Say M if you want these self tests to build as a module. 1489 Say N if you are unsure. 1490 1491config SCF_TORTURE_TEST 1492 tristate "torture tests for smp_call_function*()" 1493 depends on DEBUG_KERNEL 1494 select TORTURE_TEST 1495 help 1496 This option provides a kernel module that runs torture tests 1497 on the smp_call_function() family of primitives. The kernel 1498 module may be built after the fact on the running kernel to 1499 be tested, if desired. 1500 1501config CSD_LOCK_WAIT_DEBUG 1502 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1503 depends on DEBUG_KERNEL 1504 depends on 64BIT 1505 default n 1506 help 1507 This option enables debug prints when CPUs are slow to respond 1508 to the smp_call_function*() IPI wrappers. These debug prints 1509 include the IPI handler function currently executing (if any) 1510 and relevant stack traces. 1511 1512endmenu # lock debugging 1513 1514config TRACE_IRQFLAGS 1515 depends on TRACE_IRQFLAGS_SUPPORT 1516 bool 1517 help 1518 Enables hooks to interrupt enabling and disabling for 1519 either tracing or lock debugging. 1520 1521config TRACE_IRQFLAGS_NMI 1522 def_bool y 1523 depends on TRACE_IRQFLAGS 1524 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1525 1526config DEBUG_IRQFLAGS 1527 bool "Debug IRQ flag manipulation" 1528 help 1529 Enables checks for potentially unsafe enabling or disabling of 1530 interrupts, such as calling raw_local_irq_restore() when interrupts 1531 are enabled. 1532 1533config STACKTRACE 1534 bool "Stack backtrace support" 1535 depends on STACKTRACE_SUPPORT 1536 help 1537 This option causes the kernel to create a /proc/pid/stack for 1538 every process, showing its current stack trace. 1539 It is also used by various kernel debugging features that require 1540 stack trace generation. 1541 1542config WARN_ALL_UNSEEDED_RANDOM 1543 bool "Warn for all uses of unseeded randomness" 1544 default n 1545 help 1546 Some parts of the kernel contain bugs relating to their use of 1547 cryptographically secure random numbers before it's actually possible 1548 to generate those numbers securely. This setting ensures that these 1549 flaws don't go unnoticed, by enabling a message, should this ever 1550 occur. This will allow people with obscure setups to know when things 1551 are going wrong, so that they might contact developers about fixing 1552 it. 1553 1554 Unfortunately, on some models of some architectures getting 1555 a fully seeded CRNG is extremely difficult, and so this can 1556 result in dmesg getting spammed for a surprisingly long 1557 time. This is really bad from a security perspective, and 1558 so architecture maintainers really need to do what they can 1559 to get the CRNG seeded sooner after the system is booted. 1560 However, since users cannot do anything actionable to 1561 address this, by default the kernel will issue only a single 1562 warning for the first use of unseeded randomness. 1563 1564 Say Y here if you want to receive warnings for all uses of 1565 unseeded randomness. This will be of use primarily for 1566 those developers interested in improving the security of 1567 Linux kernels running on their architecture (or 1568 subarchitecture). 1569 1570config DEBUG_KOBJECT 1571 bool "kobject debugging" 1572 depends on DEBUG_KERNEL 1573 help 1574 If you say Y here, some extra kobject debugging messages will be sent 1575 to the syslog. 1576 1577config DEBUG_KOBJECT_RELEASE 1578 bool "kobject release debugging" 1579 depends on DEBUG_OBJECTS_TIMERS 1580 help 1581 kobjects are reference counted objects. This means that their 1582 last reference count put is not predictable, and the kobject can 1583 live on past the point at which a driver decides to drop it's 1584 initial reference to the kobject gained on allocation. An 1585 example of this would be a struct device which has just been 1586 unregistered. 1587 1588 However, some buggy drivers assume that after such an operation, 1589 the memory backing the kobject can be immediately freed. This 1590 goes completely against the principles of a refcounted object. 1591 1592 If you say Y here, the kernel will delay the release of kobjects 1593 on the last reference count to improve the visibility of this 1594 kind of kobject release bug. 1595 1596config HAVE_DEBUG_BUGVERBOSE 1597 bool 1598 1599menu "Debug kernel data structures" 1600 1601config DEBUG_LIST 1602 bool "Debug linked list manipulation" 1603 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1604 help 1605 Enable this to turn on extended checks in the linked-list 1606 walking routines. 1607 1608 If unsure, say N. 1609 1610config DEBUG_PLIST 1611 bool "Debug priority linked list manipulation" 1612 depends on DEBUG_KERNEL 1613 help 1614 Enable this to turn on extended checks in the priority-ordered 1615 linked-list (plist) walking routines. This checks the entire 1616 list multiple times during each manipulation. 1617 1618 If unsure, say N. 1619 1620config DEBUG_SG 1621 bool "Debug SG table operations" 1622 depends on DEBUG_KERNEL 1623 help 1624 Enable this to turn on checks on scatter-gather tables. This can 1625 help find problems with drivers that do not properly initialize 1626 their sg tables. 1627 1628 If unsure, say N. 1629 1630config DEBUG_NOTIFIERS 1631 bool "Debug notifier call chains" 1632 depends on DEBUG_KERNEL 1633 help 1634 Enable this to turn on sanity checking for notifier call chains. 1635 This is most useful for kernel developers to make sure that 1636 modules properly unregister themselves from notifier chains. 1637 This is a relatively cheap check but if you care about maximum 1638 performance, say N. 1639 1640config BUG_ON_DATA_CORRUPTION 1641 bool "Trigger a BUG when data corruption is detected" 1642 select DEBUG_LIST 1643 help 1644 Select this option if the kernel should BUG when it encounters 1645 data corruption in kernel memory structures when they get checked 1646 for validity. 1647 1648 If unsure, say N. 1649 1650endmenu 1651 1652config DEBUG_CREDENTIALS 1653 bool "Debug credential management" 1654 depends on DEBUG_KERNEL 1655 help 1656 Enable this to turn on some debug checking for credential 1657 management. The additional code keeps track of the number of 1658 pointers from task_structs to any given cred struct, and checks to 1659 see that this number never exceeds the usage count of the cred 1660 struct. 1661 1662 Furthermore, if SELinux is enabled, this also checks that the 1663 security pointer in the cred struct is never seen to be invalid. 1664 1665 If unsure, say N. 1666 1667source "kernel/rcu/Kconfig.debug" 1668 1669config DEBUG_WQ_FORCE_RR_CPU 1670 bool "Force round-robin CPU selection for unbound work items" 1671 depends on DEBUG_KERNEL 1672 default n 1673 help 1674 Workqueue used to implicitly guarantee that work items queued 1675 without explicit CPU specified are put on the local CPU. This 1676 guarantee is no longer true and while local CPU is still 1677 preferred work items may be put on foreign CPUs. Kernel 1678 parameter "workqueue.debug_force_rr_cpu" is added to force 1679 round-robin CPU selection to flush out usages which depend on the 1680 now broken guarantee. This config option enables the debug 1681 feature by default. When enabled, memory and cache locality will 1682 be impacted. 1683 1684config CPU_HOTPLUG_STATE_CONTROL 1685 bool "Enable CPU hotplug state control" 1686 depends on DEBUG_KERNEL 1687 depends on HOTPLUG_CPU 1688 default n 1689 help 1690 Allows to write steps between "offline" and "online" to the CPUs 1691 sysfs target file so states can be stepped granular. This is a debug 1692 option for now as the hotplug machinery cannot be stopped and 1693 restarted at arbitrary points yet. 1694 1695 Say N if your are unsure. 1696 1697config LATENCYTOP 1698 bool "Latency measuring infrastructure" 1699 depends on DEBUG_KERNEL 1700 depends on STACKTRACE_SUPPORT 1701 depends on PROC_FS 1702 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1703 select KALLSYMS 1704 select KALLSYMS_ALL 1705 select STACKTRACE 1706 select SCHEDSTATS 1707 help 1708 Enable this option if you want to use the LatencyTOP tool 1709 to find out which userspace is blocking on what kernel operations. 1710 1711source "kernel/trace/Kconfig" 1712 1713config PROVIDE_OHCI1394_DMA_INIT 1714 bool "Remote debugging over FireWire early on boot" 1715 depends on PCI && X86 1716 help 1717 If you want to debug problems which hang or crash the kernel early 1718 on boot and the crashing machine has a FireWire port, you can use 1719 this feature to remotely access the memory of the crashed machine 1720 over FireWire. This employs remote DMA as part of the OHCI1394 1721 specification which is now the standard for FireWire controllers. 1722 1723 With remote DMA, you can monitor the printk buffer remotely using 1724 firescope and access all memory below 4GB using fireproxy from gdb. 1725 Even controlling a kernel debugger is possible using remote DMA. 1726 1727 Usage: 1728 1729 If ohci1394_dma=early is used as boot parameter, it will initialize 1730 all OHCI1394 controllers which are found in the PCI config space. 1731 1732 As all changes to the FireWire bus such as enabling and disabling 1733 devices cause a bus reset and thereby disable remote DMA for all 1734 devices, be sure to have the cable plugged and FireWire enabled on 1735 the debugging host before booting the debug target for debugging. 1736 1737 This code (~1k) is freed after boot. By then, the firewire stack 1738 in charge of the OHCI-1394 controllers should be used instead. 1739 1740 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1741 1742source "samples/Kconfig" 1743 1744config ARCH_HAS_DEVMEM_IS_ALLOWED 1745 bool 1746 1747config STRICT_DEVMEM 1748 bool "Filter access to /dev/mem" 1749 depends on MMU && DEVMEM 1750 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1751 default y if PPC || X86 || ARM64 1752 help 1753 If this option is disabled, you allow userspace (root) access to all 1754 of memory, including kernel and userspace memory. Accidental 1755 access to this is obviously disastrous, but specific access can 1756 be used by people debugging the kernel. Note that with PAT support 1757 enabled, even in this case there are restrictions on /dev/mem 1758 use due to the cache aliasing requirements. 1759 1760 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1761 file only allows userspace access to PCI space and the BIOS code and 1762 data regions. This is sufficient for dosemu and X and all common 1763 users of /dev/mem. 1764 1765 If in doubt, say Y. 1766 1767config IO_STRICT_DEVMEM 1768 bool "Filter I/O access to /dev/mem" 1769 depends on STRICT_DEVMEM 1770 help 1771 If this option is disabled, you allow userspace (root) access to all 1772 io-memory regardless of whether a driver is actively using that 1773 range. Accidental access to this is obviously disastrous, but 1774 specific access can be used by people debugging kernel drivers. 1775 1776 If this option is switched on, the /dev/mem file only allows 1777 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1778 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1779 if the driver using a given range cannot be disabled. 1780 1781 If in doubt, say Y. 1782 1783menu "$(SRCARCH) Debugging" 1784 1785source "arch/$(SRCARCH)/Kconfig.debug" 1786 1787endmenu 1788 1789menu "Kernel Testing and Coverage" 1790 1791source "lib/kunit/Kconfig" 1792 1793config NOTIFIER_ERROR_INJECTION 1794 tristate "Notifier error injection" 1795 depends on DEBUG_KERNEL 1796 select DEBUG_FS 1797 help 1798 This option provides the ability to inject artificial errors to 1799 specified notifier chain callbacks. It is useful to test the error 1800 handling of notifier call chain failures. 1801 1802 Say N if unsure. 1803 1804config PM_NOTIFIER_ERROR_INJECT 1805 tristate "PM notifier error injection module" 1806 depends on PM && NOTIFIER_ERROR_INJECTION 1807 default m if PM_DEBUG 1808 help 1809 This option provides the ability to inject artificial errors to 1810 PM notifier chain callbacks. It is controlled through debugfs 1811 interface /sys/kernel/debug/notifier-error-inject/pm 1812 1813 If the notifier call chain should be failed with some events 1814 notified, write the error code to "actions/<notifier event>/error". 1815 1816 Example: Inject PM suspend error (-12 = -ENOMEM) 1817 1818 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1819 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1820 # echo mem > /sys/power/state 1821 bash: echo: write error: Cannot allocate memory 1822 1823 To compile this code as a module, choose M here: the module will 1824 be called pm-notifier-error-inject. 1825 1826 If unsure, say N. 1827 1828config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1829 tristate "OF reconfig notifier error injection module" 1830 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1831 help 1832 This option provides the ability to inject artificial errors to 1833 OF reconfig notifier chain callbacks. It is controlled 1834 through debugfs interface under 1835 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1836 1837 If the notifier call chain should be failed with some events 1838 notified, write the error code to "actions/<notifier event>/error". 1839 1840 To compile this code as a module, choose M here: the module will 1841 be called of-reconfig-notifier-error-inject. 1842 1843 If unsure, say N. 1844 1845config NETDEV_NOTIFIER_ERROR_INJECT 1846 tristate "Netdev notifier error injection module" 1847 depends on NET && NOTIFIER_ERROR_INJECTION 1848 help 1849 This option provides the ability to inject artificial errors to 1850 netdevice notifier chain callbacks. It is controlled through debugfs 1851 interface /sys/kernel/debug/notifier-error-inject/netdev 1852 1853 If the notifier call chain should be failed with some events 1854 notified, write the error code to "actions/<notifier event>/error". 1855 1856 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1857 1858 # cd /sys/kernel/debug/notifier-error-inject/netdev 1859 # echo -22 > actions/NETDEV_CHANGEMTU/error 1860 # ip link set eth0 mtu 1024 1861 RTNETLINK answers: Invalid argument 1862 1863 To compile this code as a module, choose M here: the module will 1864 be called netdev-notifier-error-inject. 1865 1866 If unsure, say N. 1867 1868config FUNCTION_ERROR_INJECTION 1869 def_bool y 1870 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1871 1872config FAULT_INJECTION 1873 bool "Fault-injection framework" 1874 depends on DEBUG_KERNEL 1875 help 1876 Provide fault-injection framework. 1877 For more details, see Documentation/fault-injection/. 1878 1879config FAILSLAB 1880 bool "Fault-injection capability for kmalloc" 1881 depends on FAULT_INJECTION 1882 depends on SLAB || SLUB 1883 help 1884 Provide fault-injection capability for kmalloc. 1885 1886config FAIL_PAGE_ALLOC 1887 bool "Fault-injection capability for alloc_pages()" 1888 depends on FAULT_INJECTION 1889 help 1890 Provide fault-injection capability for alloc_pages(). 1891 1892config FAULT_INJECTION_USERCOPY 1893 bool "Fault injection capability for usercopy functions" 1894 depends on FAULT_INJECTION 1895 help 1896 Provides fault-injection capability to inject failures 1897 in usercopy functions (copy_from_user(), get_user(), ...). 1898 1899config FAIL_MAKE_REQUEST 1900 bool "Fault-injection capability for disk IO" 1901 depends on FAULT_INJECTION && BLOCK 1902 help 1903 Provide fault-injection capability for disk IO. 1904 1905config FAIL_IO_TIMEOUT 1906 bool "Fault-injection capability for faking disk interrupts" 1907 depends on FAULT_INJECTION && BLOCK 1908 help 1909 Provide fault-injection capability on end IO handling. This 1910 will make the block layer "forget" an interrupt as configured, 1911 thus exercising the error handling. 1912 1913 Only works with drivers that use the generic timeout handling, 1914 for others it won't do anything. 1915 1916config FAIL_FUTEX 1917 bool "Fault-injection capability for futexes" 1918 select DEBUG_FS 1919 depends on FAULT_INJECTION && FUTEX 1920 help 1921 Provide fault-injection capability for futexes. 1922 1923config FAULT_INJECTION_DEBUG_FS 1924 bool "Debugfs entries for fault-injection capabilities" 1925 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1926 help 1927 Enable configuration of fault-injection capabilities via debugfs. 1928 1929config FAIL_FUNCTION 1930 bool "Fault-injection capability for functions" 1931 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1932 help 1933 Provide function-based fault-injection capability. 1934 This will allow you to override a specific function with a return 1935 with given return value. As a result, function caller will see 1936 an error value and have to handle it. This is useful to test the 1937 error handling in various subsystems. 1938 1939config FAIL_MMC_REQUEST 1940 bool "Fault-injection capability for MMC IO" 1941 depends on FAULT_INJECTION_DEBUG_FS && MMC 1942 help 1943 Provide fault-injection capability for MMC IO. 1944 This will make the mmc core return data errors. This is 1945 useful to test the error handling in the mmc block device 1946 and to test how the mmc host driver handles retries from 1947 the block device. 1948 1949config FAIL_SUNRPC 1950 bool "Fault-injection capability for SunRPC" 1951 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1952 help 1953 Provide fault-injection capability for SunRPC and 1954 its consumers. 1955 1956config FAULT_INJECTION_STACKTRACE_FILTER 1957 bool "stacktrace filter for fault-injection capabilities" 1958 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1959 depends on !X86_64 1960 select STACKTRACE 1961 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1962 help 1963 Provide stacktrace filter for fault-injection capabilities 1964 1965config ARCH_HAS_KCOV 1966 bool 1967 help 1968 An architecture should select this when it can successfully 1969 build and run with CONFIG_KCOV. This typically requires 1970 disabling instrumentation for some early boot code. 1971 1972config CC_HAS_SANCOV_TRACE_PC 1973 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1974 1975 1976config KCOV 1977 bool "Code coverage for fuzzing" 1978 depends on ARCH_HAS_KCOV 1979 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1980 select DEBUG_FS 1981 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1982 help 1983 KCOV exposes kernel code coverage information in a form suitable 1984 for coverage-guided fuzzing (randomized testing). 1985 1986 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1987 different machines and across reboots. If you need stable PC values, 1988 disable RANDOMIZE_BASE. 1989 1990 For more details, see Documentation/dev-tools/kcov.rst. 1991 1992config KCOV_ENABLE_COMPARISONS 1993 bool "Enable comparison operands collection by KCOV" 1994 depends on KCOV 1995 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 1996 help 1997 KCOV also exposes operands of every comparison in the instrumented 1998 code along with operand sizes and PCs of the comparison instructions. 1999 These operands can be used by fuzzing engines to improve the quality 2000 of fuzzing coverage. 2001 2002config KCOV_INSTRUMENT_ALL 2003 bool "Instrument all code by default" 2004 depends on KCOV 2005 default y 2006 help 2007 If you are doing generic system call fuzzing (like e.g. syzkaller), 2008 then you will want to instrument the whole kernel and you should 2009 say y here. If you are doing more targeted fuzzing (like e.g. 2010 filesystem fuzzing with AFL) then you will want to enable coverage 2011 for more specific subsets of files, and should say n here. 2012 2013config KCOV_IRQ_AREA_SIZE 2014 hex "Size of interrupt coverage collection area in words" 2015 depends on KCOV 2016 default 0x40000 2017 help 2018 KCOV uses preallocated per-cpu areas to collect coverage from 2019 soft interrupts. This specifies the size of those areas in the 2020 number of unsigned long words. 2021 2022menuconfig RUNTIME_TESTING_MENU 2023 bool "Runtime Testing" 2024 def_bool y 2025 2026if RUNTIME_TESTING_MENU 2027 2028config LKDTM 2029 tristate "Linux Kernel Dump Test Tool Module" 2030 depends on DEBUG_FS 2031 help 2032 This module enables testing of the different dumping mechanisms by 2033 inducing system failures at predefined crash points. 2034 If you don't need it: say N 2035 Choose M here to compile this code as a module. The module will be 2036 called lkdtm. 2037 2038 Documentation on how to use the module can be found in 2039 Documentation/fault-injection/provoke-crashes.rst 2040 2041config TEST_LIST_SORT 2042 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2043 depends on KUNIT 2044 default KUNIT_ALL_TESTS 2045 help 2046 Enable this to turn on 'list_sort()' function test. This test is 2047 executed only once during system boot (so affects only boot time), 2048 or at module load time. 2049 2050 If unsure, say N. 2051 2052config TEST_MIN_HEAP 2053 tristate "Min heap test" 2054 depends on DEBUG_KERNEL || m 2055 help 2056 Enable this to turn on min heap function tests. This test is 2057 executed only once during system boot (so affects only boot time), 2058 or at module load time. 2059 2060 If unsure, say N. 2061 2062config TEST_SORT 2063 tristate "Array-based sort test" if !KUNIT_ALL_TESTS 2064 depends on KUNIT 2065 default KUNIT_ALL_TESTS 2066 help 2067 This option enables the self-test function of 'sort()' at boot, 2068 or at module load time. 2069 2070 If unsure, say N. 2071 2072config TEST_DIV64 2073 tristate "64bit/32bit division and modulo test" 2074 depends on DEBUG_KERNEL || m 2075 help 2076 Enable this to turn on 'do_div()' function test. This test is 2077 executed only once during system boot (so affects only boot time), 2078 or at module load time. 2079 2080 If unsure, say N. 2081 2082config KPROBES_SANITY_TEST 2083 bool "Kprobes sanity tests" 2084 depends on DEBUG_KERNEL 2085 depends on KPROBES 2086 help 2087 This option provides for testing basic kprobes functionality on 2088 boot. Samples of kprobe and kretprobe are inserted and 2089 verified for functionality. 2090 2091 Say N if you are unsure. 2092 2093config BACKTRACE_SELF_TEST 2094 tristate "Self test for the backtrace code" 2095 depends on DEBUG_KERNEL 2096 help 2097 This option provides a kernel module that can be used to test 2098 the kernel stack backtrace code. This option is not useful 2099 for distributions or general kernels, but only for kernel 2100 developers working on architecture code. 2101 2102 Note that if you want to also test saved backtraces, you will 2103 have to enable STACKTRACE as well. 2104 2105 Say N if you are unsure. 2106 2107config RBTREE_TEST 2108 tristate "Red-Black tree test" 2109 depends on DEBUG_KERNEL 2110 help 2111 A benchmark measuring the performance of the rbtree library. 2112 Also includes rbtree invariant checks. 2113 2114config REED_SOLOMON_TEST 2115 tristate "Reed-Solomon library test" 2116 depends on DEBUG_KERNEL || m 2117 select REED_SOLOMON 2118 select REED_SOLOMON_ENC16 2119 select REED_SOLOMON_DEC16 2120 help 2121 This option enables the self-test function of rslib at boot, 2122 or at module load time. 2123 2124 If unsure, say N. 2125 2126config INTERVAL_TREE_TEST 2127 tristate "Interval tree test" 2128 depends on DEBUG_KERNEL 2129 select INTERVAL_TREE 2130 help 2131 A benchmark measuring the performance of the interval tree library 2132 2133config PERCPU_TEST 2134 tristate "Per cpu operations test" 2135 depends on m && DEBUG_KERNEL 2136 help 2137 Enable this option to build test module which validates per-cpu 2138 operations. 2139 2140 If unsure, say N. 2141 2142config ATOMIC64_SELFTEST 2143 tristate "Perform an atomic64_t self-test" 2144 help 2145 Enable this option to test the atomic64_t functions at boot or 2146 at module load time. 2147 2148 If unsure, say N. 2149 2150config ASYNC_RAID6_TEST 2151 tristate "Self test for hardware accelerated raid6 recovery" 2152 depends on ASYNC_RAID6_RECOV 2153 select ASYNC_MEMCPY 2154 help 2155 This is a one-shot self test that permutes through the 2156 recovery of all the possible two disk failure scenarios for a 2157 N-disk array. Recovery is performed with the asynchronous 2158 raid6 recovery routines, and will optionally use an offload 2159 engine if one is available. 2160 2161 If unsure, say N. 2162 2163config TEST_HEXDUMP 2164 tristate "Test functions located in the hexdump module at runtime" 2165 2166config STRING_SELFTEST 2167 tristate "Test string functions at runtime" 2168 2169config TEST_STRING_HELPERS 2170 tristate "Test functions located in the string_helpers module at runtime" 2171 2172config TEST_STRSCPY 2173 tristate "Test strscpy*() family of functions at runtime" 2174 2175config TEST_KSTRTOX 2176 tristate "Test kstrto*() family of functions at runtime" 2177 2178config TEST_PRINTF 2179 tristate "Test printf() family of functions at runtime" 2180 2181config TEST_SCANF 2182 tristate "Test scanf() family of functions at runtime" 2183 2184config TEST_BITMAP 2185 tristate "Test bitmap_*() family of functions at runtime" 2186 help 2187 Enable this option to test the bitmap functions at boot. 2188 2189 If unsure, say N. 2190 2191config TEST_UUID 2192 tristate "Test functions located in the uuid module at runtime" 2193 2194config TEST_XARRAY 2195 tristate "Test the XArray code at runtime" 2196 2197config TEST_OVERFLOW 2198 tristate "Test check_*_overflow() functions at runtime" 2199 2200config TEST_RHASHTABLE 2201 tristate "Perform selftest on resizable hash table" 2202 help 2203 Enable this option to test the rhashtable functions at boot. 2204 2205 If unsure, say N. 2206 2207config TEST_HASH 2208 tristate "Perform selftest on hash functions" 2209 help 2210 Enable this option to test the kernel's integer (<linux/hash.h>), 2211 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) 2212 hash functions on boot (or module load). 2213 2214 This is intended to help people writing architecture-specific 2215 optimized versions. If unsure, say N. 2216 2217config TEST_IDA 2218 tristate "Perform selftest on IDA functions" 2219 2220config TEST_PARMAN 2221 tristate "Perform selftest on priority array manager" 2222 depends on PARMAN 2223 help 2224 Enable this option to test priority array manager on boot 2225 (or module load). 2226 2227 If unsure, say N. 2228 2229config TEST_IRQ_TIMINGS 2230 bool "IRQ timings selftest" 2231 depends on IRQ_TIMINGS 2232 help 2233 Enable this option to test the irq timings code on boot. 2234 2235 If unsure, say N. 2236 2237config TEST_LKM 2238 tristate "Test module loading with 'hello world' module" 2239 depends on m 2240 help 2241 This builds the "test_module" module that emits "Hello, world" 2242 on printk when loaded. It is designed to be used for basic 2243 evaluation of the module loading subsystem (for example when 2244 validating module verification). It lacks any extra dependencies, 2245 and will not normally be loaded by the system unless explicitly 2246 requested by name. 2247 2248 If unsure, say N. 2249 2250config TEST_BITOPS 2251 tristate "Test module for compilation of bitops operations" 2252 depends on m 2253 help 2254 This builds the "test_bitops" module that is much like the 2255 TEST_LKM module except that it does a basic exercise of the 2256 set/clear_bit macros and get_count_order/long to make sure there are 2257 no compiler warnings from C=1 sparse checker or -Wextra 2258 compilations. It has no dependencies and doesn't run or load unless 2259 explicitly requested by name. for example: modprobe test_bitops. 2260 2261 If unsure, say N. 2262 2263config TEST_VMALLOC 2264 tristate "Test module for stress/performance analysis of vmalloc allocator" 2265 default n 2266 depends on MMU 2267 depends on m 2268 help 2269 This builds the "test_vmalloc" module that should be used for 2270 stress and performance analysis. So, any new change for vmalloc 2271 subsystem can be evaluated from performance and stability point 2272 of view. 2273 2274 If unsure, say N. 2275 2276config TEST_USER_COPY 2277 tristate "Test user/kernel boundary protections" 2278 depends on m 2279 help 2280 This builds the "test_user_copy" module that runs sanity checks 2281 on the copy_to/from_user infrastructure, making sure basic 2282 user/kernel boundary testing is working. If it fails to load, 2283 a regression has been detected in the user/kernel memory boundary 2284 protections. 2285 2286 If unsure, say N. 2287 2288config TEST_BPF 2289 tristate "Test BPF filter functionality" 2290 depends on m && NET 2291 help 2292 This builds the "test_bpf" module that runs various test vectors 2293 against the BPF interpreter or BPF JIT compiler depending on the 2294 current setting. This is in particular useful for BPF JIT compiler 2295 development, but also to run regression tests against changes in 2296 the interpreter code. It also enables test stubs for eBPF maps and 2297 verifier used by user space verifier testsuite. 2298 2299 If unsure, say N. 2300 2301config TEST_BLACKHOLE_DEV 2302 tristate "Test blackhole netdev functionality" 2303 depends on m && NET 2304 help 2305 This builds the "test_blackhole_dev" module that validates the 2306 data path through this blackhole netdev. 2307 2308 If unsure, say N. 2309 2310config FIND_BIT_BENCHMARK 2311 tristate "Test find_bit functions" 2312 help 2313 This builds the "test_find_bit" module that measure find_*_bit() 2314 functions performance. 2315 2316 If unsure, say N. 2317 2318config TEST_FIRMWARE 2319 tristate "Test firmware loading via userspace interface" 2320 depends on FW_LOADER 2321 help 2322 This builds the "test_firmware" module that creates a userspace 2323 interface for testing firmware loading. This can be used to 2324 control the triggering of firmware loading without needing an 2325 actual firmware-using device. The contents can be rechecked by 2326 userspace. 2327 2328 If unsure, say N. 2329 2330config TEST_SYSCTL 2331 tristate "sysctl test driver" 2332 depends on PROC_SYSCTL 2333 help 2334 This builds the "test_sysctl" module. This driver enables to test the 2335 proc sysctl interfaces available to drivers safely without affecting 2336 production knobs which might alter system functionality. 2337 2338 If unsure, say N. 2339 2340config BITFIELD_KUNIT 2341 tristate "KUnit test bitfield functions at runtime" 2342 depends on KUNIT 2343 help 2344 Enable this option to test the bitfield functions at boot. 2345 2346 KUnit tests run during boot and output the results to the debug log 2347 in TAP format (http://testanything.org/). Only useful for kernel devs 2348 running the KUnit test harness, and not intended for inclusion into a 2349 production build. 2350 2351 For more information on KUnit and unit tests in general please refer 2352 to the KUnit documentation in Documentation/dev-tools/kunit/. 2353 2354 If unsure, say N. 2355 2356config RESOURCE_KUNIT_TEST 2357 tristate "KUnit test for resource API" 2358 depends on KUNIT 2359 help 2360 This builds the resource API unit test. 2361 Tests the logic of API provided by resource.c and ioport.h. 2362 For more information on KUnit and unit tests in general please refer 2363 to the KUnit documentation in Documentation/dev-tools/kunit/. 2364 2365 If unsure, say N. 2366 2367config SYSCTL_KUNIT_TEST 2368 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2369 depends on KUNIT 2370 default KUNIT_ALL_TESTS 2371 help 2372 This builds the proc sysctl unit test, which runs on boot. 2373 Tests the API contract and implementation correctness of sysctl. 2374 For more information on KUnit and unit tests in general please refer 2375 to the KUnit documentation in Documentation/dev-tools/kunit/. 2376 2377 If unsure, say N. 2378 2379config LIST_KUNIT_TEST 2380 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2381 depends on KUNIT 2382 default KUNIT_ALL_TESTS 2383 help 2384 This builds the linked list KUnit test suite. 2385 It tests that the API and basic functionality of the list_head type 2386 and associated macros. 2387 2388 KUnit tests run during boot and output the results to the debug log 2389 in TAP format (https://testanything.org/). Only useful for kernel devs 2390 running the KUnit test harness, and not intended for inclusion into a 2391 production build. 2392 2393 For more information on KUnit and unit tests in general please refer 2394 to the KUnit documentation in Documentation/dev-tools/kunit/. 2395 2396 If unsure, say N. 2397 2398config LINEAR_RANGES_TEST 2399 tristate "KUnit test for linear_ranges" 2400 depends on KUNIT 2401 select LINEAR_RANGES 2402 help 2403 This builds the linear_ranges unit test, which runs on boot. 2404 Tests the linear_ranges logic correctness. 2405 For more information on KUnit and unit tests in general please refer 2406 to the KUnit documentation in Documentation/dev-tools/kunit/. 2407 2408 If unsure, say N. 2409 2410config CMDLINE_KUNIT_TEST 2411 tristate "KUnit test for cmdline API" 2412 depends on KUNIT 2413 help 2414 This builds the cmdline API unit test. 2415 Tests the logic of API provided by cmdline.c. 2416 For more information on KUnit and unit tests in general please refer 2417 to the KUnit documentation in Documentation/dev-tools/kunit/. 2418 2419 If unsure, say N. 2420 2421config BITS_TEST 2422 tristate "KUnit test for bits.h" 2423 depends on KUNIT 2424 help 2425 This builds the bits unit test. 2426 Tests the logic of macros defined in bits.h. 2427 For more information on KUnit and unit tests in general please refer 2428 to the KUnit documentation in Documentation/dev-tools/kunit/. 2429 2430 If unsure, say N. 2431 2432config SLUB_KUNIT_TEST 2433 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS 2434 depends on SLUB_DEBUG && KUNIT 2435 default KUNIT_ALL_TESTS 2436 help 2437 This builds SLUB allocator unit test. 2438 Tests SLUB cache debugging functionality. 2439 For more information on KUnit and unit tests in general please refer 2440 to the KUnit documentation in Documentation/dev-tools/kunit/. 2441 2442 If unsure, say N. 2443 2444config RATIONAL_KUNIT_TEST 2445 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS 2446 depends on KUNIT && RATIONAL 2447 default KUNIT_ALL_TESTS 2448 help 2449 This builds the rational math unit test. 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 TEST_UDELAY 2456 tristate "udelay test driver" 2457 help 2458 This builds the "udelay_test" module that helps to make sure 2459 that udelay() is working properly. 2460 2461 If unsure, say N. 2462 2463config TEST_STATIC_KEYS 2464 tristate "Test static keys" 2465 depends on m 2466 help 2467 Test the static key interfaces. 2468 2469 If unsure, say N. 2470 2471config TEST_KMOD 2472 tristate "kmod stress tester" 2473 depends on m 2474 depends on NETDEVICES && NET_CORE && INET # for TUN 2475 depends on BLOCK 2476 select TEST_LKM 2477 select XFS_FS 2478 select TUN 2479 select BTRFS_FS 2480 help 2481 Test the kernel's module loading mechanism: kmod. kmod implements 2482 support to load modules using the Linux kernel's usermode helper. 2483 This test provides a series of tests against kmod. 2484 2485 Although technically you can either build test_kmod as a module or 2486 into the kernel we disallow building it into the kernel since 2487 it stress tests request_module() and this will very likely cause 2488 some issues by taking over precious threads available from other 2489 module load requests, ultimately this could be fatal. 2490 2491 To run tests run: 2492 2493 tools/testing/selftests/kmod/kmod.sh --help 2494 2495 If unsure, say N. 2496 2497config TEST_DEBUG_VIRTUAL 2498 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2499 depends on DEBUG_VIRTUAL 2500 help 2501 Test the kernel's ability to detect incorrect calls to 2502 virt_to_phys() done against the non-linear part of the 2503 kernel's virtual address map. 2504 2505 If unsure, say N. 2506 2507config TEST_MEMCAT_P 2508 tristate "Test memcat_p() helper function" 2509 help 2510 Test the memcat_p() helper for correctly merging two 2511 pointer arrays together. 2512 2513 If unsure, say N. 2514 2515config TEST_LIVEPATCH 2516 tristate "Test livepatching" 2517 default n 2518 depends on DYNAMIC_DEBUG 2519 depends on LIVEPATCH 2520 depends on m 2521 help 2522 Test kernel livepatching features for correctness. The tests will 2523 load test modules that will be livepatched in various scenarios. 2524 2525 To run all the livepatching tests: 2526 2527 make -C tools/testing/selftests TARGETS=livepatch run_tests 2528 2529 Alternatively, individual tests may be invoked: 2530 2531 tools/testing/selftests/livepatch/test-callbacks.sh 2532 tools/testing/selftests/livepatch/test-livepatch.sh 2533 tools/testing/selftests/livepatch/test-shadow-vars.sh 2534 2535 If unsure, say N. 2536 2537config TEST_OBJAGG 2538 tristate "Perform selftest on object aggreration manager" 2539 default n 2540 depends on OBJAGG 2541 help 2542 Enable this option to test object aggregation manager on boot 2543 (or module load). 2544 2545 2546config TEST_STACKINIT 2547 tristate "Test level of stack variable initialization" 2548 help 2549 Test if the kernel is zero-initializing stack variables and 2550 padding. Coverage is controlled by compiler flags, 2551 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2552 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2553 2554 If unsure, say N. 2555 2556config TEST_MEMINIT 2557 tristate "Test heap/page initialization" 2558 help 2559 Test if the kernel is zero-initializing heap and page allocations. 2560 This can be useful to test init_on_alloc and init_on_free features. 2561 2562 If unsure, say N. 2563 2564config TEST_HMM 2565 tristate "Test HMM (Heterogeneous Memory Management)" 2566 depends on TRANSPARENT_HUGEPAGE 2567 depends on DEVICE_PRIVATE 2568 select HMM_MIRROR 2569 select MMU_NOTIFIER 2570 help 2571 This is a pseudo device driver solely for testing HMM. 2572 Say M here if you want to build the HMM test module. 2573 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2574 2575 If unsure, say N. 2576 2577config TEST_FREE_PAGES 2578 tristate "Test freeing pages" 2579 help 2580 Test that a memory leak does not occur due to a race between 2581 freeing a block of pages and a speculative page reference. 2582 Loading this module is safe if your kernel has the bug fixed. 2583 If the bug is not fixed, it will leak gigabytes of memory and 2584 probably OOM your system. 2585 2586config TEST_FPU 2587 tristate "Test floating point operations in kernel space" 2588 depends on X86 && !KCOV_INSTRUMENT_ALL 2589 help 2590 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2591 which will trigger a sequence of floating point operations. This is used 2592 for self-testing floating point control register setting in 2593 kernel_fpu_begin(). 2594 2595 If unsure, say N. 2596 2597config TEST_CLOCKSOURCE_WATCHDOG 2598 tristate "Test clocksource watchdog in kernel space" 2599 depends on CLOCKSOURCE_WATCHDOG 2600 help 2601 Enable this option to create a kernel module that will trigger 2602 a test of the clocksource watchdog. This module may be loaded 2603 via modprobe or insmod in which case it will run upon being 2604 loaded, or it may be built in, in which case it will run 2605 shortly after boot. 2606 2607 If unsure, say N. 2608 2609endif # RUNTIME_TESTING_MENU 2610 2611config ARCH_USE_MEMTEST 2612 bool 2613 help 2614 An architecture should select this when it uses early_memtest() 2615 during boot process. 2616 2617config MEMTEST 2618 bool "Memtest" 2619 depends on ARCH_USE_MEMTEST 2620 help 2621 This option adds a kernel parameter 'memtest', which allows memtest 2622 to be set and executed. 2623 memtest=0, mean disabled; -- default 2624 memtest=1, mean do 1 test pattern; 2625 ... 2626 memtest=17, mean do 17 test patterns. 2627 If you are unsure how to answer this question, answer N. 2628 2629 2630 2631config HYPERV_TESTING 2632 bool "Microsoft Hyper-V driver testing" 2633 default n 2634 depends on HYPERV && DEBUG_FS 2635 help 2636 Select this option to enable Hyper-V vmbus testing. 2637 2638endmenu # "Kernel Testing and Coverage" 2639 2640source "Documentation/Kconfig" 2641 2642endmenu # Kernel hacking 2643