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 GCC_VERSION >= 50000 || (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) 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 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH 1068 help 1069 Say Y here to enable the kernel to act as a watchdog to detect 1070 hard lockups. 1071 1072 Hardlockups are bugs that cause the CPU to loop in kernel mode 1073 for more than 10 seconds, without letting other interrupts have a 1074 chance to run. The current stack trace is displayed upon detection 1075 and the system will stay locked up. 1076 1077config BOOTPARAM_HARDLOCKUP_PANIC 1078 bool "Panic (Reboot) On Hard Lockups" 1079 depends on HARDLOCKUP_DETECTOR 1080 help 1081 Say Y here to enable the kernel to panic on "hard lockups", 1082 which are bugs that cause the kernel to loop in kernel 1083 mode with interrupts disabled for more than 10 seconds (configurable 1084 using the watchdog_thresh sysctl). 1085 1086 Say N if unsure. 1087 1088config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1089 int 1090 depends on HARDLOCKUP_DETECTOR 1091 range 0 1 1092 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1093 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1094 1095config DETECT_HUNG_TASK 1096 bool "Detect Hung Tasks" 1097 depends on DEBUG_KERNEL 1098 default SOFTLOCKUP_DETECTOR 1099 help 1100 Say Y here to enable the kernel to detect "hung tasks", 1101 which are bugs that cause the task to be stuck in 1102 uninterruptible "D" state indefinitely. 1103 1104 When a hung task is detected, the kernel will print the 1105 current stack trace (which you should report), but the 1106 task will stay in uninterruptible state. If lockdep is 1107 enabled then all held locks will also be reported. This 1108 feature has negligible overhead. 1109 1110config DEFAULT_HUNG_TASK_TIMEOUT 1111 int "Default timeout for hung task detection (in seconds)" 1112 depends on DETECT_HUNG_TASK 1113 default 120 1114 help 1115 This option controls the default timeout (in seconds) used 1116 to determine when a task has become non-responsive and should 1117 be considered hung. 1118 1119 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1120 sysctl or by writing a value to 1121 /proc/sys/kernel/hung_task_timeout_secs. 1122 1123 A timeout of 0 disables the check. The default is two minutes. 1124 Keeping the default should be fine in most cases. 1125 1126config BOOTPARAM_HUNG_TASK_PANIC 1127 bool "Panic (Reboot) On Hung Tasks" 1128 depends on DETECT_HUNG_TASK 1129 help 1130 Say Y here to enable the kernel to panic on "hung tasks", 1131 which are bugs that cause the kernel to leave a task stuck 1132 in uninterruptible "D" state. 1133 1134 The panic can be used in combination with panic_timeout, 1135 to cause the system to reboot automatically after a 1136 hung task has been detected. This feature is useful for 1137 high-availability systems that have uptime guarantees and 1138 where a hung tasks must be resolved ASAP. 1139 1140 Say N if unsure. 1141 1142config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1143 int 1144 depends on DETECT_HUNG_TASK 1145 range 0 1 1146 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1147 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1148 1149config WQ_WATCHDOG 1150 bool "Detect Workqueue Stalls" 1151 depends on DEBUG_KERNEL 1152 help 1153 Say Y here to enable stall detection on workqueues. If a 1154 worker pool doesn't make forward progress on a pending work 1155 item for over a given amount of time, 30s by default, a 1156 warning message is printed along with dump of workqueue 1157 state. This can be configured through kernel parameter 1158 "workqueue.watchdog_thresh" and its sysfs counterpart. 1159 1160config TEST_LOCKUP 1161 tristate "Test module to generate lockups" 1162 depends on m 1163 help 1164 This builds the "test_lockup" module that helps to make sure 1165 that watchdogs and lockup detectors are working properly. 1166 1167 Depending on module parameters it could emulate soft or hard 1168 lockup, "hung task", or locking arbitrary lock for a long time. 1169 Also it could generate series of lockups with cooling-down periods. 1170 1171 If unsure, say N. 1172 1173endmenu # "Debug lockups and hangs" 1174 1175menu "Scheduler Debugging" 1176 1177config SCHED_DEBUG 1178 bool "Collect scheduler debugging info" 1179 depends on DEBUG_KERNEL && PROC_FS 1180 default y 1181 help 1182 If you say Y here, the /proc/sched_debug file will be provided 1183 that can help debug the scheduler. The runtime overhead of this 1184 option is minimal. 1185 1186config SCHED_INFO 1187 bool 1188 default n 1189 1190config SCHEDSTATS 1191 bool "Collect scheduler statistics" 1192 depends on DEBUG_KERNEL && PROC_FS 1193 select SCHED_INFO 1194 help 1195 If you say Y here, additional code will be inserted into the 1196 scheduler and related routines to collect statistics about 1197 scheduler behavior and provide them in /proc/schedstat. These 1198 stats may be useful for both tuning and debugging the scheduler 1199 If you aren't debugging the scheduler or trying to tune a specific 1200 application, you can say N to avoid the very slight overhead 1201 this adds. 1202 1203endmenu 1204 1205config DEBUG_TIMEKEEPING 1206 bool "Enable extra timekeeping sanity checking" 1207 help 1208 This option will enable additional timekeeping sanity checks 1209 which may be helpful when diagnosing issues where timekeeping 1210 problems are suspected. 1211 1212 This may include checks in the timekeeping hotpaths, so this 1213 option may have a (very small) performance impact to some 1214 workloads. 1215 1216 If unsure, say N. 1217 1218config DEBUG_PREEMPT 1219 bool "Debug preemptible kernel" 1220 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1221 default y 1222 help 1223 If you say Y here then the kernel will use a debug variant of the 1224 commonly used smp_processor_id() function and will print warnings 1225 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1226 will detect preemption count underflows. 1227 1228menu "Lock Debugging (spinlocks, mutexes, etc...)" 1229 1230config LOCK_DEBUGGING_SUPPORT 1231 bool 1232 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1233 default y 1234 1235config PROVE_LOCKING 1236 bool "Lock debugging: prove locking correctness" 1237 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1238 select LOCKDEP 1239 select DEBUG_SPINLOCK 1240 select DEBUG_MUTEXES if !PREEMPT_RT 1241 select DEBUG_RT_MUTEXES if RT_MUTEXES 1242 select DEBUG_RWSEMS 1243 select DEBUG_WW_MUTEX_SLOWPATH 1244 select DEBUG_LOCK_ALLOC 1245 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1246 select TRACE_IRQFLAGS 1247 default n 1248 help 1249 This feature enables the kernel to prove that all locking 1250 that occurs in the kernel runtime is mathematically 1251 correct: that under no circumstance could an arbitrary (and 1252 not yet triggered) combination of observed locking 1253 sequences (on an arbitrary number of CPUs, running an 1254 arbitrary number of tasks and interrupt contexts) cause a 1255 deadlock. 1256 1257 In short, this feature enables the kernel to report locking 1258 related deadlocks before they actually occur. 1259 1260 The proof does not depend on how hard and complex a 1261 deadlock scenario would be to trigger: how many 1262 participant CPUs, tasks and irq-contexts would be needed 1263 for it to trigger. The proof also does not depend on 1264 timing: if a race and a resulting deadlock is possible 1265 theoretically (no matter how unlikely the race scenario 1266 is), it will be proven so and will immediately be 1267 reported by the kernel (once the event is observed that 1268 makes the deadlock theoretically possible). 1269 1270 If a deadlock is impossible (i.e. the locking rules, as 1271 observed by the kernel, are mathematically correct), the 1272 kernel reports nothing. 1273 1274 NOTE: this feature can also be enabled for rwlocks, mutexes 1275 and rwsems - in which case all dependencies between these 1276 different locking variants are observed and mapped too, and 1277 the proof of observed correctness is also maintained for an 1278 arbitrary combination of these separate locking variants. 1279 1280 For more details, see Documentation/locking/lockdep-design.rst. 1281 1282config PROVE_RAW_LOCK_NESTING 1283 bool "Enable raw_spinlock - spinlock nesting checks" 1284 depends on PROVE_LOCKING 1285 default n 1286 help 1287 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1288 that the lock nesting rules for PREEMPT_RT enabled kernels are 1289 not violated. 1290 1291 NOTE: There are known nesting problems. So if you enable this 1292 option expect lockdep splats until these problems have been fully 1293 addressed which is work in progress. This config switch allows to 1294 identify and analyze these problems. It will be removed and the 1295 check permanently enabled once the main issues have been fixed. 1296 1297 If unsure, select N. 1298 1299config LOCK_STAT 1300 bool "Lock usage statistics" 1301 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1302 select LOCKDEP 1303 select DEBUG_SPINLOCK 1304 select DEBUG_MUTEXES if !PREEMPT_RT 1305 select DEBUG_RT_MUTEXES if RT_MUTEXES 1306 select DEBUG_LOCK_ALLOC 1307 default n 1308 help 1309 This feature enables tracking lock contention points 1310 1311 For more details, see Documentation/locking/lockstat.rst 1312 1313 This also enables lock events required by "perf lock", 1314 subcommand of perf. 1315 If you want to use "perf lock", you also need to turn on 1316 CONFIG_EVENT_TRACING. 1317 1318 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1319 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1320 1321config DEBUG_RT_MUTEXES 1322 bool "RT Mutex debugging, deadlock detection" 1323 depends on DEBUG_KERNEL && RT_MUTEXES 1324 help 1325 This allows rt mutex semantics violations and rt mutex related 1326 deadlocks (lockups) to be detected and reported automatically. 1327 1328config DEBUG_SPINLOCK 1329 bool "Spinlock and rw-lock debugging: basic checks" 1330 depends on DEBUG_KERNEL 1331 select UNINLINE_SPIN_UNLOCK 1332 help 1333 Say Y here and build SMP to catch missing spinlock initialization 1334 and certain other kinds of spinlock errors commonly made. This is 1335 best used in conjunction with the NMI watchdog so that spinlock 1336 deadlocks are also debuggable. 1337 1338config DEBUG_MUTEXES 1339 bool "Mutex debugging: basic checks" 1340 depends on DEBUG_KERNEL && !PREEMPT_RT 1341 help 1342 This feature allows mutex semantics violations to be detected and 1343 reported. 1344 1345config DEBUG_WW_MUTEX_SLOWPATH 1346 bool "Wait/wound mutex debugging: Slowpath testing" 1347 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1348 select DEBUG_LOCK_ALLOC 1349 select DEBUG_SPINLOCK 1350 select DEBUG_MUTEXES if !PREEMPT_RT 1351 select DEBUG_RT_MUTEXES if PREEMPT_RT 1352 help 1353 This feature enables slowpath testing for w/w mutex users by 1354 injecting additional -EDEADLK wound/backoff cases. Together with 1355 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1356 will test all possible w/w mutex interface abuse with the 1357 exception of simply not acquiring all the required locks. 1358 Note that this feature can introduce significant overhead, so 1359 it really should not be enabled in a production or distro kernel, 1360 even a debug kernel. If you are a driver writer, enable it. If 1361 you are a distro, do not. 1362 1363config DEBUG_RWSEMS 1364 bool "RW Semaphore debugging: basic checks" 1365 depends on DEBUG_KERNEL 1366 help 1367 This debugging feature allows mismatched rw semaphore locks 1368 and unlocks to be detected and reported. 1369 1370config DEBUG_LOCK_ALLOC 1371 bool "Lock debugging: detect incorrect freeing of live locks" 1372 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1373 select DEBUG_SPINLOCK 1374 select DEBUG_MUTEXES if !PREEMPT_RT 1375 select DEBUG_RT_MUTEXES if RT_MUTEXES 1376 select LOCKDEP 1377 help 1378 This feature will check whether any held lock (spinlock, rwlock, 1379 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1380 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1381 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1382 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1383 held during task exit. 1384 1385config LOCKDEP 1386 bool 1387 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1388 select STACKTRACE 1389 select KALLSYMS 1390 select KALLSYMS_ALL 1391 1392config LOCKDEP_SMALL 1393 bool 1394 1395config LOCKDEP_BITS 1396 int "Bitsize for MAX_LOCKDEP_ENTRIES" 1397 depends on LOCKDEP && !LOCKDEP_SMALL 1398 range 10 30 1399 default 15 1400 help 1401 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message. 1402 1403config LOCKDEP_CHAINS_BITS 1404 int "Bitsize for MAX_LOCKDEP_CHAINS" 1405 depends on LOCKDEP && !LOCKDEP_SMALL 1406 range 10 30 1407 default 16 1408 help 1409 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message. 1410 1411config LOCKDEP_STACK_TRACE_BITS 1412 int "Bitsize for MAX_STACK_TRACE_ENTRIES" 1413 depends on LOCKDEP && !LOCKDEP_SMALL 1414 range 10 30 1415 default 19 1416 help 1417 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message. 1418 1419config LOCKDEP_STACK_TRACE_HASH_BITS 1420 int "Bitsize for STACK_TRACE_HASH_SIZE" 1421 depends on LOCKDEP && !LOCKDEP_SMALL 1422 range 10 30 1423 default 14 1424 help 1425 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES. 1426 1427config LOCKDEP_CIRCULAR_QUEUE_BITS 1428 int "Bitsize for elements in circular_queue struct" 1429 depends on LOCKDEP 1430 range 10 30 1431 default 12 1432 help 1433 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure. 1434 1435config DEBUG_LOCKDEP 1436 bool "Lock dependency engine debugging" 1437 depends on DEBUG_KERNEL && LOCKDEP 1438 select DEBUG_IRQFLAGS 1439 help 1440 If you say Y here, the lock dependency engine will do 1441 additional runtime checks to debug itself, at the price 1442 of more runtime overhead. 1443 1444config DEBUG_ATOMIC_SLEEP 1445 bool "Sleep inside atomic section checking" 1446 select PREEMPT_COUNT 1447 depends on DEBUG_KERNEL 1448 depends on !ARCH_NO_PREEMPT 1449 help 1450 If you say Y here, various routines which may sleep will become very 1451 noisy if they are called inside atomic sections: when a spinlock is 1452 held, inside an rcu read side critical section, inside preempt disabled 1453 sections, inside an interrupt, etc... 1454 1455config DEBUG_LOCKING_API_SELFTESTS 1456 bool "Locking API boot-time self-tests" 1457 depends on DEBUG_KERNEL 1458 help 1459 Say Y here if you want the kernel to run a short self-test during 1460 bootup. The self-test checks whether common types of locking bugs 1461 are detected by debugging mechanisms or not. (if you disable 1462 lock debugging then those bugs won't be detected of course.) 1463 The following locking APIs are covered: spinlocks, rwlocks, 1464 mutexes and rwsems. 1465 1466config LOCK_TORTURE_TEST 1467 tristate "torture tests for locking" 1468 depends on DEBUG_KERNEL 1469 select TORTURE_TEST 1470 help 1471 This option provides a kernel module that runs torture tests 1472 on kernel locking primitives. The kernel module may be built 1473 after the fact on the running kernel to be tested, if desired. 1474 1475 Say Y here if you want kernel locking-primitive torture tests 1476 to be built into the kernel. 1477 Say M if you want these torture tests to build as a module. 1478 Say N if you are unsure. 1479 1480config WW_MUTEX_SELFTEST 1481 tristate "Wait/wound mutex selftests" 1482 help 1483 This option provides a kernel module that runs tests on the 1484 on the struct ww_mutex locking API. 1485 1486 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1487 with this test harness. 1488 1489 Say M if you want these self tests to build as a module. 1490 Say N if you are unsure. 1491 1492config SCF_TORTURE_TEST 1493 tristate "torture tests for smp_call_function*()" 1494 depends on DEBUG_KERNEL 1495 select TORTURE_TEST 1496 help 1497 This option provides a kernel module that runs torture tests 1498 on the smp_call_function() family of primitives. The kernel 1499 module may be built after the fact on the running kernel to 1500 be tested, if desired. 1501 1502config CSD_LOCK_WAIT_DEBUG 1503 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1504 depends on DEBUG_KERNEL 1505 depends on 64BIT 1506 default n 1507 help 1508 This option enables debug prints when CPUs are slow to respond 1509 to the smp_call_function*() IPI wrappers. These debug prints 1510 include the IPI handler function currently executing (if any) 1511 and relevant stack traces. 1512 1513endmenu # lock debugging 1514 1515config TRACE_IRQFLAGS 1516 depends on TRACE_IRQFLAGS_SUPPORT 1517 bool 1518 help 1519 Enables hooks to interrupt enabling and disabling for 1520 either tracing or lock debugging. 1521 1522config TRACE_IRQFLAGS_NMI 1523 def_bool y 1524 depends on TRACE_IRQFLAGS 1525 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1526 1527config DEBUG_IRQFLAGS 1528 bool "Debug IRQ flag manipulation" 1529 help 1530 Enables checks for potentially unsafe enabling or disabling of 1531 interrupts, such as calling raw_local_irq_restore() when interrupts 1532 are enabled. 1533 1534config STACKTRACE 1535 bool "Stack backtrace support" 1536 depends on STACKTRACE_SUPPORT 1537 help 1538 This option causes the kernel to create a /proc/pid/stack for 1539 every process, showing its current stack trace. 1540 It is also used by various kernel debugging features that require 1541 stack trace generation. 1542 1543config WARN_ALL_UNSEEDED_RANDOM 1544 bool "Warn for all uses of unseeded randomness" 1545 default n 1546 help 1547 Some parts of the kernel contain bugs relating to their use of 1548 cryptographically secure random numbers before it's actually possible 1549 to generate those numbers securely. This setting ensures that these 1550 flaws don't go unnoticed, by enabling a message, should this ever 1551 occur. This will allow people with obscure setups to know when things 1552 are going wrong, so that they might contact developers about fixing 1553 it. 1554 1555 Unfortunately, on some models of some architectures getting 1556 a fully seeded CRNG is extremely difficult, and so this can 1557 result in dmesg getting spammed for a surprisingly long 1558 time. This is really bad from a security perspective, and 1559 so architecture maintainers really need to do what they can 1560 to get the CRNG seeded sooner after the system is booted. 1561 However, since users cannot do anything actionable to 1562 address this, by default the kernel will issue only a single 1563 warning for the first use of unseeded randomness. 1564 1565 Say Y here if you want to receive warnings for all uses of 1566 unseeded randomness. This will be of use primarily for 1567 those developers interested in improving the security of 1568 Linux kernels running on their architecture (or 1569 subarchitecture). 1570 1571config DEBUG_KOBJECT 1572 bool "kobject debugging" 1573 depends on DEBUG_KERNEL 1574 help 1575 If you say Y here, some extra kobject debugging messages will be sent 1576 to the syslog. 1577 1578config DEBUG_KOBJECT_RELEASE 1579 bool "kobject release debugging" 1580 depends on DEBUG_OBJECTS_TIMERS 1581 help 1582 kobjects are reference counted objects. This means that their 1583 last reference count put is not predictable, and the kobject can 1584 live on past the point at which a driver decides to drop it's 1585 initial reference to the kobject gained on allocation. An 1586 example of this would be a struct device which has just been 1587 unregistered. 1588 1589 However, some buggy drivers assume that after such an operation, 1590 the memory backing the kobject can be immediately freed. This 1591 goes completely against the principles of a refcounted object. 1592 1593 If you say Y here, the kernel will delay the release of kobjects 1594 on the last reference count to improve the visibility of this 1595 kind of kobject release bug. 1596 1597config HAVE_DEBUG_BUGVERBOSE 1598 bool 1599 1600menu "Debug kernel data structures" 1601 1602config DEBUG_LIST 1603 bool "Debug linked list manipulation" 1604 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1605 help 1606 Enable this to turn on extended checks in the linked-list 1607 walking routines. 1608 1609 If unsure, say N. 1610 1611config DEBUG_PLIST 1612 bool "Debug priority linked list manipulation" 1613 depends on DEBUG_KERNEL 1614 help 1615 Enable this to turn on extended checks in the priority-ordered 1616 linked-list (plist) walking routines. This checks the entire 1617 list multiple times during each manipulation. 1618 1619 If unsure, say N. 1620 1621config DEBUG_SG 1622 bool "Debug SG table operations" 1623 depends on DEBUG_KERNEL 1624 help 1625 Enable this to turn on checks on scatter-gather tables. This can 1626 help find problems with drivers that do not properly initialize 1627 their sg tables. 1628 1629 If unsure, say N. 1630 1631config DEBUG_NOTIFIERS 1632 bool "Debug notifier call chains" 1633 depends on DEBUG_KERNEL 1634 help 1635 Enable this to turn on sanity checking for notifier call chains. 1636 This is most useful for kernel developers to make sure that 1637 modules properly unregister themselves from notifier chains. 1638 This is a relatively cheap check but if you care about maximum 1639 performance, say N. 1640 1641config BUG_ON_DATA_CORRUPTION 1642 bool "Trigger a BUG when data corruption is detected" 1643 select DEBUG_LIST 1644 help 1645 Select this option if the kernel should BUG when it encounters 1646 data corruption in kernel memory structures when they get checked 1647 for validity. 1648 1649 If unsure, say N. 1650 1651endmenu 1652 1653config DEBUG_CREDENTIALS 1654 bool "Debug credential management" 1655 depends on DEBUG_KERNEL 1656 help 1657 Enable this to turn on some debug checking for credential 1658 management. The additional code keeps track of the number of 1659 pointers from task_structs to any given cred struct, and checks to 1660 see that this number never exceeds the usage count of the cred 1661 struct. 1662 1663 Furthermore, if SELinux is enabled, this also checks that the 1664 security pointer in the cred struct is never seen to be invalid. 1665 1666 If unsure, say N. 1667 1668source "kernel/rcu/Kconfig.debug" 1669 1670config DEBUG_WQ_FORCE_RR_CPU 1671 bool "Force round-robin CPU selection for unbound work items" 1672 depends on DEBUG_KERNEL 1673 default n 1674 help 1675 Workqueue used to implicitly guarantee that work items queued 1676 without explicit CPU specified are put on the local CPU. This 1677 guarantee is no longer true and while local CPU is still 1678 preferred work items may be put on foreign CPUs. Kernel 1679 parameter "workqueue.debug_force_rr_cpu" is added to force 1680 round-robin CPU selection to flush out usages which depend on the 1681 now broken guarantee. This config option enables the debug 1682 feature by default. When enabled, memory and cache locality will 1683 be impacted. 1684 1685config CPU_HOTPLUG_STATE_CONTROL 1686 bool "Enable CPU hotplug state control" 1687 depends on DEBUG_KERNEL 1688 depends on HOTPLUG_CPU 1689 default n 1690 help 1691 Allows to write steps between "offline" and "online" to the CPUs 1692 sysfs target file so states can be stepped granular. This is a debug 1693 option for now as the hotplug machinery cannot be stopped and 1694 restarted at arbitrary points yet. 1695 1696 Say N if your are unsure. 1697 1698config LATENCYTOP 1699 bool "Latency measuring infrastructure" 1700 depends on DEBUG_KERNEL 1701 depends on STACKTRACE_SUPPORT 1702 depends on PROC_FS 1703 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1704 select KALLSYMS 1705 select KALLSYMS_ALL 1706 select STACKTRACE 1707 select SCHEDSTATS 1708 help 1709 Enable this option if you want to use the LatencyTOP tool 1710 to find out which userspace is blocking on what kernel operations. 1711 1712source "kernel/trace/Kconfig" 1713 1714config PROVIDE_OHCI1394_DMA_INIT 1715 bool "Remote debugging over FireWire early on boot" 1716 depends on PCI && X86 1717 help 1718 If you want to debug problems which hang or crash the kernel early 1719 on boot and the crashing machine has a FireWire port, you can use 1720 this feature to remotely access the memory of the crashed machine 1721 over FireWire. This employs remote DMA as part of the OHCI1394 1722 specification which is now the standard for FireWire controllers. 1723 1724 With remote DMA, you can monitor the printk buffer remotely using 1725 firescope and access all memory below 4GB using fireproxy from gdb. 1726 Even controlling a kernel debugger is possible using remote DMA. 1727 1728 Usage: 1729 1730 If ohci1394_dma=early is used as boot parameter, it will initialize 1731 all OHCI1394 controllers which are found in the PCI config space. 1732 1733 As all changes to the FireWire bus such as enabling and disabling 1734 devices cause a bus reset and thereby disable remote DMA for all 1735 devices, be sure to have the cable plugged and FireWire enabled on 1736 the debugging host before booting the debug target for debugging. 1737 1738 This code (~1k) is freed after boot. By then, the firewire stack 1739 in charge of the OHCI-1394 controllers should be used instead. 1740 1741 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1742 1743source "samples/Kconfig" 1744 1745config ARCH_HAS_DEVMEM_IS_ALLOWED 1746 bool 1747 1748config STRICT_DEVMEM 1749 bool "Filter access to /dev/mem" 1750 depends on MMU && DEVMEM 1751 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED 1752 default y if PPC || X86 || ARM64 1753 help 1754 If this option is disabled, you allow userspace (root) access to all 1755 of memory, including kernel and userspace memory. Accidental 1756 access to this is obviously disastrous, but specific access can 1757 be used by people debugging the kernel. Note that with PAT support 1758 enabled, even in this case there are restrictions on /dev/mem 1759 use due to the cache aliasing requirements. 1760 1761 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1762 file only allows userspace access to PCI space and the BIOS code and 1763 data regions. This is sufficient for dosemu and X and all common 1764 users of /dev/mem. 1765 1766 If in doubt, say Y. 1767 1768config IO_STRICT_DEVMEM 1769 bool "Filter I/O access to /dev/mem" 1770 depends on STRICT_DEVMEM 1771 help 1772 If this option is disabled, you allow userspace (root) access to all 1773 io-memory regardless of whether a driver is actively using that 1774 range. Accidental access to this is obviously disastrous, but 1775 specific access can be used by people debugging kernel drivers. 1776 1777 If this option is switched on, the /dev/mem file only allows 1778 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1779 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1780 if the driver using a given range cannot be disabled. 1781 1782 If in doubt, say Y. 1783 1784menu "$(SRCARCH) Debugging" 1785 1786source "arch/$(SRCARCH)/Kconfig.debug" 1787 1788endmenu 1789 1790menu "Kernel Testing and Coverage" 1791 1792source "lib/kunit/Kconfig" 1793 1794config NOTIFIER_ERROR_INJECTION 1795 tristate "Notifier error injection" 1796 depends on DEBUG_KERNEL 1797 select DEBUG_FS 1798 help 1799 This option provides the ability to inject artificial errors to 1800 specified notifier chain callbacks. It is useful to test the error 1801 handling of notifier call chain failures. 1802 1803 Say N if unsure. 1804 1805config PM_NOTIFIER_ERROR_INJECT 1806 tristate "PM notifier error injection module" 1807 depends on PM && NOTIFIER_ERROR_INJECTION 1808 default m if PM_DEBUG 1809 help 1810 This option provides the ability to inject artificial errors to 1811 PM notifier chain callbacks. It is controlled through debugfs 1812 interface /sys/kernel/debug/notifier-error-inject/pm 1813 1814 If the notifier call chain should be failed with some events 1815 notified, write the error code to "actions/<notifier event>/error". 1816 1817 Example: Inject PM suspend error (-12 = -ENOMEM) 1818 1819 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1820 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1821 # echo mem > /sys/power/state 1822 bash: echo: write error: Cannot allocate memory 1823 1824 To compile this code as a module, choose M here: the module will 1825 be called pm-notifier-error-inject. 1826 1827 If unsure, say N. 1828 1829config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1830 tristate "OF reconfig notifier error injection module" 1831 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1832 help 1833 This option provides the ability to inject artificial errors to 1834 OF reconfig notifier chain callbacks. It is controlled 1835 through debugfs interface under 1836 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1837 1838 If the notifier call chain should be failed with some events 1839 notified, write the error code to "actions/<notifier event>/error". 1840 1841 To compile this code as a module, choose M here: the module will 1842 be called of-reconfig-notifier-error-inject. 1843 1844 If unsure, say N. 1845 1846config NETDEV_NOTIFIER_ERROR_INJECT 1847 tristate "Netdev notifier error injection module" 1848 depends on NET && NOTIFIER_ERROR_INJECTION 1849 help 1850 This option provides the ability to inject artificial errors to 1851 netdevice notifier chain callbacks. It is controlled through debugfs 1852 interface /sys/kernel/debug/notifier-error-inject/netdev 1853 1854 If the notifier call chain should be failed with some events 1855 notified, write the error code to "actions/<notifier event>/error". 1856 1857 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1858 1859 # cd /sys/kernel/debug/notifier-error-inject/netdev 1860 # echo -22 > actions/NETDEV_CHANGEMTU/error 1861 # ip link set eth0 mtu 1024 1862 RTNETLINK answers: Invalid argument 1863 1864 To compile this code as a module, choose M here: the module will 1865 be called netdev-notifier-error-inject. 1866 1867 If unsure, say N. 1868 1869config FUNCTION_ERROR_INJECTION 1870 def_bool y 1871 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1872 1873config FAULT_INJECTION 1874 bool "Fault-injection framework" 1875 depends on DEBUG_KERNEL 1876 help 1877 Provide fault-injection framework. 1878 For more details, see Documentation/fault-injection/. 1879 1880config FAILSLAB 1881 bool "Fault-injection capability for kmalloc" 1882 depends on FAULT_INJECTION 1883 depends on SLAB || SLUB 1884 help 1885 Provide fault-injection capability for kmalloc. 1886 1887config FAIL_PAGE_ALLOC 1888 bool "Fault-injection capability for alloc_pages()" 1889 depends on FAULT_INJECTION 1890 help 1891 Provide fault-injection capability for alloc_pages(). 1892 1893config FAULT_INJECTION_USERCOPY 1894 bool "Fault injection capability for usercopy functions" 1895 depends on FAULT_INJECTION 1896 help 1897 Provides fault-injection capability to inject failures 1898 in usercopy functions (copy_from_user(), get_user(), ...). 1899 1900config FAIL_MAKE_REQUEST 1901 bool "Fault-injection capability for disk IO" 1902 depends on FAULT_INJECTION && BLOCK 1903 help 1904 Provide fault-injection capability for disk IO. 1905 1906config FAIL_IO_TIMEOUT 1907 bool "Fault-injection capability for faking disk interrupts" 1908 depends on FAULT_INJECTION && BLOCK 1909 help 1910 Provide fault-injection capability on end IO handling. This 1911 will make the block layer "forget" an interrupt as configured, 1912 thus exercising the error handling. 1913 1914 Only works with drivers that use the generic timeout handling, 1915 for others it won't do anything. 1916 1917config FAIL_FUTEX 1918 bool "Fault-injection capability for futexes" 1919 select DEBUG_FS 1920 depends on FAULT_INJECTION && FUTEX 1921 help 1922 Provide fault-injection capability for futexes. 1923 1924config FAULT_INJECTION_DEBUG_FS 1925 bool "Debugfs entries for fault-injection capabilities" 1926 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1927 help 1928 Enable configuration of fault-injection capabilities via debugfs. 1929 1930config FAIL_FUNCTION 1931 bool "Fault-injection capability for functions" 1932 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1933 help 1934 Provide function-based fault-injection capability. 1935 This will allow you to override a specific function with a return 1936 with given return value. As a result, function caller will see 1937 an error value and have to handle it. This is useful to test the 1938 error handling in various subsystems. 1939 1940config FAIL_MMC_REQUEST 1941 bool "Fault-injection capability for MMC IO" 1942 depends on FAULT_INJECTION_DEBUG_FS && MMC 1943 help 1944 Provide fault-injection capability for MMC IO. 1945 This will make the mmc core return data errors. This is 1946 useful to test the error handling in the mmc block device 1947 and to test how the mmc host driver handles retries from 1948 the block device. 1949 1950config FAIL_SUNRPC 1951 bool "Fault-injection capability for SunRPC" 1952 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG 1953 help 1954 Provide fault-injection capability for SunRPC and 1955 its consumers. 1956 1957config FAULT_INJECTION_STACKTRACE_FILTER 1958 bool "stacktrace filter for fault-injection capabilities" 1959 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1960 depends on !X86_64 1961 select STACKTRACE 1962 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86 1963 help 1964 Provide stacktrace filter for fault-injection capabilities 1965 1966config ARCH_HAS_KCOV 1967 bool 1968 help 1969 An architecture should select this when it can successfully 1970 build and run with CONFIG_KCOV. This typically requires 1971 disabling instrumentation for some early boot code. 1972 1973config CC_HAS_SANCOV_TRACE_PC 1974 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1975 1976 1977config KCOV 1978 bool "Code coverage for fuzzing" 1979 depends on ARCH_HAS_KCOV 1980 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1981 select DEBUG_FS 1982 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1983 help 1984 KCOV exposes kernel code coverage information in a form suitable 1985 for coverage-guided fuzzing (randomized testing). 1986 1987 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1988 different machines and across reboots. If you need stable PC values, 1989 disable RANDOMIZE_BASE. 1990 1991 For more details, see Documentation/dev-tools/kcov.rst. 1992 1993config KCOV_ENABLE_COMPARISONS 1994 bool "Enable comparison operands collection by KCOV" 1995 depends on KCOV 1996 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 1997 help 1998 KCOV also exposes operands of every comparison in the instrumented 1999 code along with operand sizes and PCs of the comparison instructions. 2000 These operands can be used by fuzzing engines to improve the quality 2001 of fuzzing coverage. 2002 2003config KCOV_INSTRUMENT_ALL 2004 bool "Instrument all code by default" 2005 depends on KCOV 2006 default y 2007 help 2008 If you are doing generic system call fuzzing (like e.g. syzkaller), 2009 then you will want to instrument the whole kernel and you should 2010 say y here. If you are doing more targeted fuzzing (like e.g. 2011 filesystem fuzzing with AFL) then you will want to enable coverage 2012 for more specific subsets of files, and should say n here. 2013 2014config KCOV_IRQ_AREA_SIZE 2015 hex "Size of interrupt coverage collection area in words" 2016 depends on KCOV 2017 default 0x40000 2018 help 2019 KCOV uses preallocated per-cpu areas to collect coverage from 2020 soft interrupts. This specifies the size of those areas in the 2021 number of unsigned long words. 2022 2023menuconfig RUNTIME_TESTING_MENU 2024 bool "Runtime Testing" 2025 def_bool y 2026 2027if RUNTIME_TESTING_MENU 2028 2029config LKDTM 2030 tristate "Linux Kernel Dump Test Tool Module" 2031 depends on DEBUG_FS 2032 help 2033 This module enables testing of the different dumping mechanisms by 2034 inducing system failures at predefined crash points. 2035 If you don't need it: say N 2036 Choose M here to compile this code as a module. The module will be 2037 called lkdtm. 2038 2039 Documentation on how to use the module can be found in 2040 Documentation/fault-injection/provoke-crashes.rst 2041 2042config TEST_LIST_SORT 2043 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS 2044 depends on KUNIT 2045 default KUNIT_ALL_TESTS 2046 help 2047 Enable this to turn on 'list_sort()' function test. This test is 2048 executed only once during system boot (so affects only boot time), 2049 or at module load time. 2050 2051 If unsure, say N. 2052 2053config TEST_MIN_HEAP 2054 tristate "Min heap test" 2055 depends on DEBUG_KERNEL || m 2056 help 2057 Enable this to turn on min heap function tests. This test is 2058 executed only once during system boot (so affects only boot time), 2059 or at module load time. 2060 2061 If unsure, say N. 2062 2063config TEST_SORT 2064 tristate "Array-based sort test" 2065 depends on DEBUG_KERNEL || m 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 2447 select RATIONAL 2448 default KUNIT_ALL_TESTS 2449 help 2450 This builds the rational math unit test. 2451 For more information on KUnit and unit tests in general please refer 2452 to the KUnit documentation in Documentation/dev-tools/kunit/. 2453 2454 If unsure, say N. 2455 2456config TEST_UDELAY 2457 tristate "udelay test driver" 2458 help 2459 This builds the "udelay_test" module that helps to make sure 2460 that udelay() is working properly. 2461 2462 If unsure, say N. 2463 2464config TEST_STATIC_KEYS 2465 tristate "Test static keys" 2466 depends on m 2467 help 2468 Test the static key interfaces. 2469 2470 If unsure, say N. 2471 2472config TEST_KMOD 2473 tristate "kmod stress tester" 2474 depends on m 2475 depends on NETDEVICES && NET_CORE && INET # for TUN 2476 depends on BLOCK 2477 select TEST_LKM 2478 select XFS_FS 2479 select TUN 2480 select BTRFS_FS 2481 help 2482 Test the kernel's module loading mechanism: kmod. kmod implements 2483 support to load modules using the Linux kernel's usermode helper. 2484 This test provides a series of tests against kmod. 2485 2486 Although technically you can either build test_kmod as a module or 2487 into the kernel we disallow building it into the kernel since 2488 it stress tests request_module() and this will very likely cause 2489 some issues by taking over precious threads available from other 2490 module load requests, ultimately this could be fatal. 2491 2492 To run tests run: 2493 2494 tools/testing/selftests/kmod/kmod.sh --help 2495 2496 If unsure, say N. 2497 2498config TEST_DEBUG_VIRTUAL 2499 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2500 depends on DEBUG_VIRTUAL 2501 help 2502 Test the kernel's ability to detect incorrect calls to 2503 virt_to_phys() done against the non-linear part of the 2504 kernel's virtual address map. 2505 2506 If unsure, say N. 2507 2508config TEST_MEMCAT_P 2509 tristate "Test memcat_p() helper function" 2510 help 2511 Test the memcat_p() helper for correctly merging two 2512 pointer arrays together. 2513 2514 If unsure, say N. 2515 2516config TEST_LIVEPATCH 2517 tristate "Test livepatching" 2518 default n 2519 depends on DYNAMIC_DEBUG 2520 depends on LIVEPATCH 2521 depends on m 2522 help 2523 Test kernel livepatching features for correctness. The tests will 2524 load test modules that will be livepatched in various scenarios. 2525 2526 To run all the livepatching tests: 2527 2528 make -C tools/testing/selftests TARGETS=livepatch run_tests 2529 2530 Alternatively, individual tests may be invoked: 2531 2532 tools/testing/selftests/livepatch/test-callbacks.sh 2533 tools/testing/selftests/livepatch/test-livepatch.sh 2534 tools/testing/selftests/livepatch/test-shadow-vars.sh 2535 2536 If unsure, say N. 2537 2538config TEST_OBJAGG 2539 tristate "Perform selftest on object aggreration manager" 2540 default n 2541 depends on OBJAGG 2542 help 2543 Enable this option to test object aggregation manager on boot 2544 (or module load). 2545 2546 2547config TEST_STACKINIT 2548 tristate "Test level of stack variable initialization" 2549 help 2550 Test if the kernel is zero-initializing stack variables and 2551 padding. Coverage is controlled by compiler flags, 2552 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2553 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2554 2555 If unsure, say N. 2556 2557config TEST_MEMINIT 2558 tristate "Test heap/page initialization" 2559 help 2560 Test if the kernel is zero-initializing heap and page allocations. 2561 This can be useful to test init_on_alloc and init_on_free features. 2562 2563 If unsure, say N. 2564 2565config TEST_HMM 2566 tristate "Test HMM (Heterogeneous Memory Management)" 2567 depends on TRANSPARENT_HUGEPAGE 2568 depends on DEVICE_PRIVATE 2569 select HMM_MIRROR 2570 select MMU_NOTIFIER 2571 help 2572 This is a pseudo device driver solely for testing HMM. 2573 Say M here if you want to build the HMM test module. 2574 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2575 2576 If unsure, say N. 2577 2578config TEST_FREE_PAGES 2579 tristate "Test freeing pages" 2580 help 2581 Test that a memory leak does not occur due to a race between 2582 freeing a block of pages and a speculative page reference. 2583 Loading this module is safe if your kernel has the bug fixed. 2584 If the bug is not fixed, it will leak gigabytes of memory and 2585 probably OOM your system. 2586 2587config TEST_FPU 2588 tristate "Test floating point operations in kernel space" 2589 depends on X86 && !KCOV_INSTRUMENT_ALL 2590 help 2591 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2592 which will trigger a sequence of floating point operations. This is used 2593 for self-testing floating point control register setting in 2594 kernel_fpu_begin(). 2595 2596 If unsure, say N. 2597 2598config TEST_CLOCKSOURCE_WATCHDOG 2599 tristate "Test clocksource watchdog in kernel space" 2600 depends on CLOCKSOURCE_WATCHDOG 2601 help 2602 Enable this option to create a kernel module that will trigger 2603 a test of the clocksource watchdog. This module may be loaded 2604 via modprobe or insmod in which case it will run upon being 2605 loaded, or it may be built in, in which case it will run 2606 shortly after boot. 2607 2608 If unsure, say N. 2609 2610endif # RUNTIME_TESTING_MENU 2611 2612config ARCH_USE_MEMTEST 2613 bool 2614 help 2615 An architecture should select this when it uses early_memtest() 2616 during boot process. 2617 2618config MEMTEST 2619 bool "Memtest" 2620 depends on ARCH_USE_MEMTEST 2621 help 2622 This option adds a kernel parameter 'memtest', which allows memtest 2623 to be set and executed. 2624 memtest=0, mean disabled; -- default 2625 memtest=1, mean do 1 test pattern; 2626 ... 2627 memtest=17, mean do 17 test patterns. 2628 If you are unsure how to answer this question, answer N. 2629 2630 2631 2632config HYPERV_TESTING 2633 bool "Microsoft Hyper-V driver testing" 2634 default n 2635 depends on HYPERV && DEBUG_FS 2636 help 2637 Select this option to enable Hyper-V vmbus testing. 2638 2639endmenu # "Kernel Testing and Coverage" 2640 2641source "Documentation/Kconfig" 2642 2643endmenu # Kernel hacking 2644