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 CONSOLE_LOGLEVEL_DEFAULT 39 int "Default console loglevel (1-15)" 40 range 1 15 41 default "7" 42 help 43 Default loglevel to determine what will be printed on the console. 44 45 Setting a default here is equivalent to passing in loglevel=<x> in 46 the kernel bootargs. loglevel=<x> continues to override whatever 47 value is specified here as well. 48 49 Note: This does not affect the log level of un-prefixed printk() 50 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT 51 option. 52 53config CONSOLE_LOGLEVEL_QUIET 54 int "quiet console loglevel (1-15)" 55 range 1 15 56 default "4" 57 help 58 loglevel to use when "quiet" is passed on the kernel commandline. 59 60 When "quiet" is passed on the kernel commandline this loglevel 61 will be used as the loglevel. IOW passing "quiet" will be the 62 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>" 63 64config MESSAGE_LOGLEVEL_DEFAULT 65 int "Default message log level (1-7)" 66 range 1 7 67 default "4" 68 help 69 Default log level for printk statements with no specified priority. 70 71 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks 72 that are auditing their logs closely may want to set it to a lower 73 priority. 74 75 Note: This does not affect what message level gets printed on the console 76 by default. To change that, use loglevel=<x> in the kernel bootargs, 77 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value. 78 79config BOOT_PRINTK_DELAY 80 bool "Delay each boot printk message by N milliseconds" 81 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY 82 help 83 This build option allows you to read kernel boot messages 84 by inserting a short delay after each one. The delay is 85 specified in milliseconds on the kernel command line, 86 using "boot_delay=N". 87 88 It is likely that you would also need to use "lpj=M" to preset 89 the "loops per jiffie" value. 90 See a previous boot log for the "lpj" value to use for your 91 system, and then set "lpj=M" before setting "boot_delay=N". 92 NOTE: Using this option may adversely affect SMP systems. 93 I.e., processors other than the first one may not boot up. 94 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect 95 what it believes to be lockup conditions. 96 97config DYNAMIC_DEBUG 98 bool "Enable dynamic printk() support" 99 default n 100 depends on PRINTK 101 depends on (DEBUG_FS || PROC_FS) 102 select DYNAMIC_DEBUG_CORE 103 help 104 105 Compiles debug level messages into the kernel, which would not 106 otherwise be available at runtime. These messages can then be 107 enabled/disabled based on various levels of scope - per source file, 108 function, module, format string, and line number. This mechanism 109 implicitly compiles in all pr_debug() and dev_dbg() calls, which 110 enlarges the kernel text size by about 2%. 111 112 If a source file is compiled with DEBUG flag set, any 113 pr_debug() calls in it are enabled by default, but can be 114 disabled at runtime as below. Note that DEBUG flag is 115 turned on by many CONFIG_*DEBUG* options. 116 117 Usage: 118 119 Dynamic debugging is controlled via the 'dynamic_debug/control' file, 120 which is contained in the 'debugfs' filesystem or procfs. 121 Thus, the debugfs or procfs filesystem must first be mounted before 122 making use of this feature. 123 We refer the control file as: <debugfs>/dynamic_debug/control. This 124 file contains a list of the debug statements that can be enabled. The 125 format for each line of the file is: 126 127 filename:lineno [module]function flags format 128 129 filename : source file of the debug statement 130 lineno : line number of the debug statement 131 module : module that contains the debug statement 132 function : function that contains the debug statement 133 flags : '=p' means the line is turned 'on' for printing 134 format : the format used for the debug statement 135 136 From a live system: 137 138 nullarbor:~ # cat <debugfs>/dynamic_debug/control 139 # filename:lineno [module]function flags format 140 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012" 141 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012" 142 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012" 143 144 Example usage: 145 146 // enable the message at line 1603 of file svcsock.c 147 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > 148 <debugfs>/dynamic_debug/control 149 150 // enable all the messages in file svcsock.c 151 nullarbor:~ # echo -n 'file svcsock.c +p' > 152 <debugfs>/dynamic_debug/control 153 154 // enable all the messages in the NFS server module 155 nullarbor:~ # echo -n 'module nfsd +p' > 156 <debugfs>/dynamic_debug/control 157 158 // enable all 12 messages in the function svc_process() 159 nullarbor:~ # echo -n 'func svc_process +p' > 160 <debugfs>/dynamic_debug/control 161 162 // disable all 12 messages in the function svc_process() 163 nullarbor:~ # echo -n 'func svc_process -p' > 164 <debugfs>/dynamic_debug/control 165 166 See Documentation/admin-guide/dynamic-debug-howto.rst for additional 167 information. 168 169config DYNAMIC_DEBUG_CORE 170 bool "Enable core function of dynamic debug support" 171 depends on PRINTK 172 depends on (DEBUG_FS || PROC_FS) 173 help 174 Enable core functional support of dynamic debug. It is useful 175 when you want to tie dynamic debug to your kernel modules with 176 DYNAMIC_DEBUG_MODULE defined for each of them, especially for 177 the case of embedded system where the kernel image size is 178 sensitive for people. 179 180config SYMBOLIC_ERRNAME 181 bool "Support symbolic error names in printf" 182 default y if PRINTK 183 help 184 If you say Y here, the kernel's printf implementation will 185 be able to print symbolic error names such as ENOSPC instead 186 of the number 28. It makes the kernel image slightly larger 187 (about 3KB), but can make the kernel logs easier to read. 188 189config DEBUG_BUGVERBOSE 190 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT 191 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE) 192 default y 193 help 194 Say Y here to make BUG() panics output the file name and line number 195 of the BUG call as well as the EIP and oops trace. This aids 196 debugging but costs about 70-100K of memory. 197 198endmenu # "printk and dmesg options" 199 200menu "Compile-time checks and compiler options" 201 202config DEBUG_INFO 203 bool "Compile the kernel with debug info" 204 depends on DEBUG_KERNEL && !COMPILE_TEST 205 help 206 If you say Y here the resulting kernel image will include 207 debugging info resulting in a larger kernel image. 208 This adds debug symbols to the kernel and modules (gcc -g), and 209 is needed if you intend to use kernel crashdump or binary object 210 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 211 Say Y here only if you plan to debug the kernel. 212 213 If unsure, say N. 214 215if DEBUG_INFO 216 217config DEBUG_INFO_REDUCED 218 bool "Reduce debugging information" 219 help 220 If you say Y here gcc is instructed to generate less debugging 221 information for structure types. This means that tools that 222 need full debugging information (like kgdb or systemtap) won't 223 be happy. But if you merely need debugging information to 224 resolve line numbers there is no loss. Advantage is that 225 build directory object sizes shrink dramatically over a full 226 DEBUG_INFO build and compile times are reduced too. 227 Only works with newer gcc versions. 228 229config DEBUG_INFO_COMPRESSED 230 bool "Compressed debugging information" 231 depends on $(cc-option,-gz=zlib) 232 depends on $(ld-option,--compress-debug-sections=zlib) 233 help 234 Compress the debug information using zlib. Requires GCC 5.0+ or Clang 235 5.0+, binutils 2.26+, and zlib. 236 237 Users of dpkg-deb via scripts/package/builddeb may find an increase in 238 size of their debug .deb packages with this config set, due to the 239 debug info being compressed with zlib, then the object files being 240 recompressed with a different compression scheme. But this is still 241 preferable to setting $KDEB_COMPRESS to "none" which would be even 242 larger. 243 244config DEBUG_INFO_SPLIT 245 bool "Produce split debuginfo in .dwo files" 246 depends on $(cc-option,-gsplit-dwarf) 247 help 248 Generate debug info into separate .dwo files. This significantly 249 reduces the build directory size for builds with DEBUG_INFO, 250 because it stores the information only once on disk in .dwo 251 files instead of multiple times in object files and executables. 252 In addition the debug information is also compressed. 253 254 Requires recent gcc (4.7+) and recent gdb/binutils. 255 Any tool that packages or reads debug information would need 256 to know about the .dwo files and include them. 257 Incompatible with older versions of ccache. 258 259config DEBUG_INFO_DWARF4 260 bool "Generate dwarf4 debuginfo" 261 depends on $(cc-option,-gdwarf-4) 262 help 263 Generate dwarf4 debug info. This requires recent versions 264 of gcc and gdb. It makes the debug information larger. 265 But it significantly improves the success of resolving 266 variables in gdb on optimized code. 267 268config DEBUG_INFO_BTF 269 bool "Generate BTF typeinfo" 270 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED 271 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST 272 help 273 Generate deduplicated BTF type information from DWARF debug info. 274 Turning this on expects presence of pahole tool, which will convert 275 DWARF type info into equivalent deduplicated BTF type info. 276 277config GDB_SCRIPTS 278 bool "Provide GDB scripts for kernel debugging" 279 help 280 This creates the required links to GDB helper scripts in the 281 build directory. If you load vmlinux into gdb, the helper 282 scripts will be automatically imported by gdb as well, and 283 additional functions are available to analyze a Linux kernel 284 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 285 for further details. 286 287endif # DEBUG_INFO 288 289config ENABLE_MUST_CHECK 290 bool "Enable __must_check logic" 291 default y 292 help 293 Enable the __must_check logic in the kernel build. Disable this to 294 suppress the "warning: ignoring return value of 'foo', declared with 295 attribute warn_unused_result" messages. 296 297config FRAME_WARN 298 int "Warn for stack frames larger than" 299 range 0 8192 300 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 301 default 1280 if (!64BIT && PARISC) 302 default 1024 if (!64BIT && !PARISC) 303 default 2048 if 64BIT 304 help 305 Tell gcc to warn at build time for stack frames larger than this. 306 Setting this too low will cause a lot of warnings. 307 Setting it to 0 disables the warning. 308 309config STRIP_ASM_SYMS 310 bool "Strip assembler-generated symbols during link" 311 default n 312 help 313 Strip internal assembler-generated symbols during a link (symbols 314 that look like '.Lxxx') so they don't pollute the output of 315 get_wchan() and suchlike. 316 317config READABLE_ASM 318 bool "Generate readable assembler code" 319 depends on DEBUG_KERNEL 320 help 321 Disable some compiler optimizations that tend to generate human unreadable 322 assembler output. This may make the kernel slightly slower, but it helps 323 to keep kernel developers who have to stare a lot at assembler listings 324 sane. 325 326config HEADERS_INSTALL 327 bool "Install uapi headers to usr/include" 328 depends on !UML 329 help 330 This option will install uapi headers (headers exported to user-space) 331 into the usr/include directory for use during the kernel build. 332 This is unneeded for building the kernel itself, but needed for some 333 user-space program samples. It is also needed by some features such 334 as uapi header sanity checks. 335 336config DEBUG_SECTION_MISMATCH 337 bool "Enable full Section mismatch analysis" 338 help 339 The section mismatch analysis checks if there are illegal 340 references from one section to another section. 341 During linktime or runtime, some sections are dropped; 342 any use of code/data previously in these sections would 343 most likely result in an oops. 344 In the code, functions and variables are annotated with 345 __init,, etc. (see the full list in include/linux/init.h), 346 which results in the code/data being placed in specific sections. 347 The section mismatch analysis is always performed after a full 348 kernel build, and enabling this option causes the following 349 additional step to occur: 350 - Add the option -fno-inline-functions-called-once to gcc commands. 351 When inlining a function annotated with __init in a non-init 352 function, we would lose the section information and thus 353 the analysis would not catch the illegal reference. 354 This option tells gcc to inline less (but it does result in 355 a larger kernel). 356 357config SECTION_MISMATCH_WARN_ONLY 358 bool "Make section mismatch errors non-fatal" 359 default y 360 help 361 If you say N here, the build process will fail if there are any 362 section mismatch, instead of just throwing warnings. 363 364 If unsure, say Y. 365 366config DEBUG_FORCE_FUNCTION_ALIGN_32B 367 bool "Force all function address 32B aligned" if EXPERT 368 help 369 There are cases that a commit from one domain changes the function 370 address alignment of other domains, and cause magic performance 371 bump (regression or improvement). Enable this option will help to 372 verify if the bump is caused by function alignment changes, while 373 it will slightly increase the kernel size and affect icache usage. 374 375 It is mainly for debug and performance tuning use. 376 377# 378# Select this config option from the architecture Kconfig, if it 379# is preferred to always offer frame pointers as a config 380# option on the architecture (regardless of KERNEL_DEBUG): 381# 382config ARCH_WANT_FRAME_POINTERS 383 bool 384 385config FRAME_POINTER 386 bool "Compile the kernel with frame pointers" 387 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 388 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 389 help 390 If you say Y here the resulting kernel image will be slightly 391 larger and slower, but it gives very useful debugging information 392 in case of kernel bugs. (precise oopses/stacktraces/warnings) 393 394config STACK_VALIDATION 395 bool "Compile-time stack metadata validation" 396 depends on HAVE_STACK_VALIDATION 397 default n 398 help 399 Add compile-time checks to validate stack metadata, including frame 400 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure 401 that runtime stack traces are more reliable. 402 403 This is also a prerequisite for generation of ORC unwind data, which 404 is needed for CONFIG_UNWINDER_ORC. 405 406 For more information, see 407 tools/objtool/Documentation/stack-validation.txt. 408 409config VMLINUX_VALIDATION 410 bool 411 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT 412 default y 413 414config DEBUG_FORCE_WEAK_PER_CPU 415 bool "Force weak per-cpu definitions" 416 depends on DEBUG_KERNEL 417 help 418 s390 and alpha require percpu variables in modules to be 419 defined weak to work around addressing range issue which 420 puts the following two restrictions on percpu variable 421 definitions. 422 423 1. percpu symbols must be unique whether static or not 424 2. percpu variables can't be defined inside a function 425 426 To ensure that generic code follows the above rules, this 427 option forces all percpu variables to be defined as weak. 428 429endmenu # "Compiler options" 430 431menu "Generic Kernel Debugging Instruments" 432 433config MAGIC_SYSRQ 434 bool "Magic SysRq key" 435 depends on !UML 436 help 437 If you say Y here, you will have some control over the system even 438 if the system crashes for example during kernel debugging (e.g., you 439 will be able to flush the buffer cache to disk, reboot the system 440 immediately or dump some status information). This is accomplished 441 by pressing various keys while holding SysRq (Alt+PrintScreen). It 442 also works on a serial console (on PC hardware at least), if you 443 send a BREAK and then within 5 seconds a command keypress. The 444 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 445 Don't say Y unless you really know what this hack does. 446 447config MAGIC_SYSRQ_DEFAULT_ENABLE 448 hex "Enable magic SysRq key functions by default" 449 depends on MAGIC_SYSRQ 450 default 0x1 451 help 452 Specifies which SysRq key functions are enabled by default. 453 This may be set to 1 or 0 to enable or disable them all, or 454 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 455 456config MAGIC_SYSRQ_SERIAL 457 bool "Enable magic SysRq key over serial" 458 depends on MAGIC_SYSRQ 459 default y 460 help 461 Many embedded boards have a disconnected TTL level serial which can 462 generate some garbage that can lead to spurious false sysrq detects. 463 This option allows you to decide whether you want to enable the 464 magic SysRq key. 465 466config MAGIC_SYSRQ_SERIAL_SEQUENCE 467 string "Char sequence that enables magic SysRq over serial" 468 depends on MAGIC_SYSRQ_SERIAL 469 default "" 470 help 471 Specifies a sequence of characters that can follow BREAK to enable 472 SysRq on a serial console. 473 474 If unsure, leave an empty string and the option will not be enabled. 475 476config DEBUG_FS 477 bool "Debug Filesystem" 478 help 479 debugfs is a virtual file system that kernel developers use to put 480 debugging files into. Enable this option to be able to read and 481 write to these files. 482 483 For detailed documentation on the debugfs API, see 484 Documentation/filesystems/. 485 486 If unsure, say N. 487 488choice 489 prompt "Debugfs default access" 490 depends on DEBUG_FS 491 default DEBUG_FS_ALLOW_ALL 492 help 493 This selects the default access restrictions for debugfs. 494 It can be overridden with kernel command line option 495 debugfs=[on,no-mount,off]. The restrictions apply for API access 496 and filesystem registration. 497 498config DEBUG_FS_ALLOW_ALL 499 bool "Access normal" 500 help 501 No restrictions apply. Both API and filesystem registration 502 is on. This is the normal default operation. 503 504config DEBUG_FS_DISALLOW_MOUNT 505 bool "Do not register debugfs as filesystem" 506 help 507 The API is open but filesystem is not loaded. Clients can still do 508 their work and read with debug tools that do not need 509 debugfs filesystem. 510 511config DEBUG_FS_ALLOW_NONE 512 bool "No access" 513 help 514 Access is off. Clients get -PERM when trying to create nodes in 515 debugfs tree and debugfs is not registered as a filesystem. 516 Client can then back-off or continue without debugfs access. 517 518endchoice 519 520source "lib/Kconfig.kgdb" 521source "lib/Kconfig.ubsan" 522source "lib/Kconfig.kcsan" 523 524endmenu 525 526config DEBUG_KERNEL 527 bool "Kernel debugging" 528 help 529 Say Y here if you are developing drivers or trying to debug and 530 identify kernel problems. 531 532config DEBUG_MISC 533 bool "Miscellaneous debug code" 534 default DEBUG_KERNEL 535 depends on DEBUG_KERNEL 536 help 537 Say Y here if you need to enable miscellaneous debug code that should 538 be under a more specific debug option but isn't. 539 540 541menu "Memory Debugging" 542 543source "mm/Kconfig.debug" 544 545config DEBUG_OBJECTS 546 bool "Debug object operations" 547 depends on DEBUG_KERNEL 548 help 549 If you say Y here, additional code will be inserted into the 550 kernel to track the life time of various objects and validate 551 the operations on those objects. 552 553config DEBUG_OBJECTS_SELFTEST 554 bool "Debug objects selftest" 555 depends on DEBUG_OBJECTS 556 help 557 This enables the selftest of the object debug code. 558 559config DEBUG_OBJECTS_FREE 560 bool "Debug objects in freed memory" 561 depends on DEBUG_OBJECTS 562 help 563 This enables checks whether a k/v free operation frees an area 564 which contains an object which has not been deactivated 565 properly. This can make kmalloc/kfree-intensive workloads 566 much slower. 567 568config DEBUG_OBJECTS_TIMERS 569 bool "Debug timer objects" 570 depends on DEBUG_OBJECTS 571 help 572 If you say Y here, additional code will be inserted into the 573 timer routines to track the life time of timer objects and 574 validate the timer operations. 575 576config DEBUG_OBJECTS_WORK 577 bool "Debug work objects" 578 depends on DEBUG_OBJECTS 579 help 580 If you say Y here, additional code will be inserted into the 581 work queue routines to track the life time of work objects and 582 validate the work operations. 583 584config DEBUG_OBJECTS_RCU_HEAD 585 bool "Debug RCU callbacks objects" 586 depends on DEBUG_OBJECTS 587 help 588 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 589 590config DEBUG_OBJECTS_PERCPU_COUNTER 591 bool "Debug percpu counter objects" 592 depends on DEBUG_OBJECTS 593 help 594 If you say Y here, additional code will be inserted into the 595 percpu counter routines to track the life time of percpu counter 596 objects and validate the percpu counter operations. 597 598config DEBUG_OBJECTS_ENABLE_DEFAULT 599 int "debug_objects bootup default value (0-1)" 600 range 0 1 601 default "1" 602 depends on DEBUG_OBJECTS 603 help 604 Debug objects boot parameter default value 605 606config DEBUG_SLAB 607 bool "Debug slab memory allocations" 608 depends on DEBUG_KERNEL && SLAB 609 help 610 Say Y here to have the kernel do limited verification on memory 611 allocation as well as poisoning memory on free to catch use of freed 612 memory. This can make kmalloc/kfree-intensive workloads much slower. 613 614config SLUB_DEBUG_ON 615 bool "SLUB debugging on by default" 616 depends on SLUB && SLUB_DEBUG 617 default n 618 help 619 Boot with debugging on by default. SLUB boots by default with 620 the runtime debug capabilities switched off. Enabling this is 621 equivalent to specifying the "slub_debug" parameter on boot. 622 There is no support for more fine grained debug control like 623 possible with slub_debug=xxx. SLUB debugging may be switched 624 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 625 "slub_debug=-". 626 627config SLUB_STATS 628 default n 629 bool "Enable SLUB performance statistics" 630 depends on SLUB && SYSFS 631 help 632 SLUB statistics are useful to debug SLUBs allocation behavior in 633 order find ways to optimize the allocator. This should never be 634 enabled for production use since keeping statistics slows down 635 the allocator by a few percentage points. The slabinfo command 636 supports the determination of the most active slabs to figure 637 out which slabs are relevant to a particular load. 638 Try running: slabinfo -DA 639 640config HAVE_DEBUG_KMEMLEAK 641 bool 642 643config DEBUG_KMEMLEAK 644 bool "Kernel memory leak detector" 645 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 646 select DEBUG_FS 647 select STACKTRACE if STACKTRACE_SUPPORT 648 select KALLSYMS 649 select CRC32 650 help 651 Say Y here if you want to enable the memory leak 652 detector. The memory allocation/freeing is traced in a way 653 similar to the Boehm's conservative garbage collector, the 654 difference being that the orphan objects are not freed but 655 only shown in /sys/kernel/debug/kmemleak. Enabling this 656 feature will introduce an overhead to memory 657 allocations. See Documentation/dev-tools/kmemleak.rst for more 658 details. 659 660 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 661 of finding leaks due to the slab objects poisoning. 662 663 In order to access the kmemleak file, debugfs needs to be 664 mounted (usually at /sys/kernel/debug). 665 666config DEBUG_KMEMLEAK_MEM_POOL_SIZE 667 int "Kmemleak memory pool size" 668 depends on DEBUG_KMEMLEAK 669 range 200 1000000 670 default 16000 671 help 672 Kmemleak must track all the memory allocations to avoid 673 reporting false positives. Since memory may be allocated or 674 freed before kmemleak is fully initialised, use a static pool 675 of metadata objects to track such callbacks. After kmemleak is 676 fully initialised, this memory pool acts as an emergency one 677 if slab allocations fail. 678 679config DEBUG_KMEMLEAK_TEST 680 tristate "Simple test for the kernel memory leak detector" 681 depends on DEBUG_KMEMLEAK && m 682 help 683 This option enables a module that explicitly leaks memory. 684 685 If unsure, say N. 686 687config DEBUG_KMEMLEAK_DEFAULT_OFF 688 bool "Default kmemleak to off" 689 depends on DEBUG_KMEMLEAK 690 help 691 Say Y here to disable kmemleak by default. It can then be enabled 692 on the command line via kmemleak=on. 693 694config DEBUG_KMEMLEAK_AUTO_SCAN 695 bool "Enable kmemleak auto scan thread on boot up" 696 default y 697 depends on DEBUG_KMEMLEAK 698 help 699 Depending on the cpu, kmemleak scan may be cpu intensive and can 700 stall user tasks at times. This option enables/disables automatic 701 kmemleak scan at boot up. 702 703 Say N here to disable kmemleak auto scan thread to stop automatic 704 scanning. Disabling this option disables automatic reporting of 705 memory leaks. 706 707 If unsure, say Y. 708 709config DEBUG_STACK_USAGE 710 bool "Stack utilization instrumentation" 711 depends on DEBUG_KERNEL && !IA64 712 help 713 Enables the display of the minimum amount of free stack which each 714 task has ever had available in the sysrq-T and sysrq-P debug output. 715 716 This option will slow down process creation somewhat. 717 718config SCHED_STACK_END_CHECK 719 bool "Detect stack corruption on calls to schedule()" 720 depends on DEBUG_KERNEL 721 default n 722 help 723 This option checks for a stack overrun on calls to schedule(). 724 If the stack end location is found to be over written always panic as 725 the content of the corrupted region can no longer be trusted. 726 This is to ensure no erroneous behaviour occurs which could result in 727 data corruption or a sporadic crash at a later stage once the region 728 is examined. The runtime overhead introduced is minimal. 729 730config ARCH_HAS_DEBUG_VM_PGTABLE 731 bool 732 help 733 An architecture should select this when it can successfully 734 build and run DEBUG_VM_PGTABLE. 735 736config DEBUG_VM 737 bool "Debug VM" 738 depends on DEBUG_KERNEL 739 help 740 Enable this to turn on extended checks in the virtual-memory system 741 that may impact performance. 742 743 If unsure, say N. 744 745config DEBUG_VM_VMACACHE 746 bool "Debug VMA caching" 747 depends on DEBUG_VM 748 help 749 Enable this to turn on VMA caching debug information. Doing so 750 can cause significant overhead, so only enable it in non-production 751 environments. 752 753 If unsure, say N. 754 755config DEBUG_VM_RB 756 bool "Debug VM red-black trees" 757 depends on DEBUG_VM 758 help 759 Enable VM red-black tree debugging information and extra validations. 760 761 If unsure, say N. 762 763config DEBUG_VM_PGFLAGS 764 bool "Debug page-flags operations" 765 depends on DEBUG_VM 766 help 767 Enables extra validation on page flags operations. 768 769 If unsure, say N. 770 771config DEBUG_VM_PGTABLE 772 bool "Debug arch page table for semantics compliance" 773 depends on MMU 774 depends on ARCH_HAS_DEBUG_VM_PGTABLE 775 default y if DEBUG_VM 776 help 777 This option provides a debug method which can be used to test 778 architecture page table helper functions on various platforms in 779 verifying if they comply with expected generic MM semantics. This 780 will help architecture code in making sure that any changes or 781 new additions of these helpers still conform to expected 782 semantics of the generic MM. Platforms will have to opt in for 783 this through ARCH_HAS_DEBUG_VM_PGTABLE. 784 785 If unsure, say N. 786 787config ARCH_HAS_DEBUG_VIRTUAL 788 bool 789 790config DEBUG_VIRTUAL 791 bool "Debug VM translations" 792 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 793 help 794 Enable some costly sanity checks in virtual to page code. This can 795 catch mistakes with virt_to_page() and friends. 796 797 If unsure, say N. 798 799config DEBUG_NOMMU_REGIONS 800 bool "Debug the global anon/private NOMMU mapping region tree" 801 depends on DEBUG_KERNEL && !MMU 802 help 803 This option causes the global tree of anonymous and private mapping 804 regions to be regularly checked for invalid topology. 805 806config DEBUG_MEMORY_INIT 807 bool "Debug memory initialisation" if EXPERT 808 default !EXPERT 809 help 810 Enable this for additional checks during memory initialisation. 811 The sanity checks verify aspects of the VM such as the memory model 812 and other information provided by the architecture. Verbose 813 information will be printed at KERN_DEBUG loglevel depending 814 on the mminit_loglevel= command-line option. 815 816 If unsure, say Y 817 818config MEMORY_NOTIFIER_ERROR_INJECT 819 tristate "Memory hotplug notifier error injection module" 820 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION 821 help 822 This option provides the ability to inject artificial errors to 823 memory hotplug notifier chain callbacks. It is controlled through 824 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 825 826 If the notifier call chain should be failed with some events 827 notified, write the error code to "actions/<notifier event>/error". 828 829 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 830 831 # cd /sys/kernel/debug/notifier-error-inject/memory 832 # echo -12 > actions/MEM_GOING_OFFLINE/error 833 # echo offline > /sys/devices/system/memory/memoryXXX/state 834 bash: echo: write error: Cannot allocate memory 835 836 To compile this code as a module, choose M here: the module will 837 be called memory-notifier-error-inject. 838 839 If unsure, say N. 840 841config DEBUG_PER_CPU_MAPS 842 bool "Debug access to per_cpu maps" 843 depends on DEBUG_KERNEL 844 depends on SMP 845 help 846 Say Y to verify that the per_cpu map being accessed has 847 been set up. This adds a fair amount of code to kernel memory 848 and decreases performance. 849 850 Say N if unsure. 851 852config DEBUG_HIGHMEM 853 bool "Highmem debugging" 854 depends on DEBUG_KERNEL && HIGHMEM 855 help 856 This option enables additional error checking for high memory 857 systems. Disable for production systems. 858 859config HAVE_DEBUG_STACKOVERFLOW 860 bool 861 862config DEBUG_STACKOVERFLOW 863 bool "Check for stack overflows" 864 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 865 help 866 Say Y here if you want to check for overflows of kernel, IRQ 867 and exception stacks (if your architecture uses them). This 868 option will show detailed messages if free stack space drops 869 below a certain limit. 870 871 These kinds of bugs usually occur when call-chains in the 872 kernel get too deep, especially when interrupts are 873 involved. 874 875 Use this in cases where you see apparently random memory 876 corruption, especially if it appears in 'struct thread_info' 877 878 If in doubt, say "N". 879 880source "lib/Kconfig.kasan" 881 882endmenu # "Memory Debugging" 883 884config DEBUG_SHIRQ 885 bool "Debug shared IRQ handlers" 886 depends on DEBUG_KERNEL 887 help 888 Enable this to generate a spurious interrupt just before a shared 889 interrupt handler is deregistered (generating one when registering 890 is currently disabled). Drivers need to handle this correctly. Some 891 don't and need to be caught. 892 893menu "Debug Oops, Lockups and Hangs" 894 895config PANIC_ON_OOPS 896 bool "Panic on Oops" 897 help 898 Say Y here to enable the kernel to panic when it oopses. This 899 has the same effect as setting oops=panic on the kernel command 900 line. 901 902 This feature is useful to ensure that the kernel does not do 903 anything erroneous after an oops which could result in data 904 corruption or other issues. 905 906 Say N if unsure. 907 908config PANIC_ON_OOPS_VALUE 909 int 910 range 0 1 911 default 0 if !PANIC_ON_OOPS 912 default 1 if PANIC_ON_OOPS 913 914config PANIC_TIMEOUT 915 int "panic timeout" 916 default 0 917 help 918 Set the timeout value (in seconds) until a reboot occurs when 919 the kernel panics. If n = 0, then we wait forever. A timeout 920 value n > 0 will wait n seconds before rebooting, while a timeout 921 value n < 0 will reboot immediately. 922 923config LOCKUP_DETECTOR 924 bool 925 926config SOFTLOCKUP_DETECTOR 927 bool "Detect Soft Lockups" 928 depends on DEBUG_KERNEL && !S390 929 select LOCKUP_DETECTOR 930 help 931 Say Y here to enable the kernel to act as a watchdog to detect 932 soft lockups. 933 934 Softlockups are bugs that cause the kernel to loop in kernel 935 mode for more than 20 seconds, without giving other tasks a 936 chance to run. The current stack trace is displayed upon 937 detection and the system will stay locked up. 938 939config BOOTPARAM_SOFTLOCKUP_PANIC 940 bool "Panic (Reboot) On Soft Lockups" 941 depends on SOFTLOCKUP_DETECTOR 942 help 943 Say Y here to enable the kernel to panic on "soft lockups", 944 which are bugs that cause the kernel to loop in kernel 945 mode for more than 20 seconds (configurable using the watchdog_thresh 946 sysctl), without giving other tasks a chance to run. 947 948 The panic can be used in combination with panic_timeout, 949 to cause the system to reboot automatically after a 950 lockup has been detected. This feature is useful for 951 high-availability systems that have uptime guarantees and 952 where a lockup must be resolved ASAP. 953 954 Say N if unsure. 955 956config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 957 int 958 depends on SOFTLOCKUP_DETECTOR 959 range 0 1 960 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 961 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 962 963config HARDLOCKUP_DETECTOR_PERF 964 bool 965 select SOFTLOCKUP_DETECTOR 966 967# 968# Enables a timestamp based low pass filter to compensate for perf based 969# hard lockup detection which runs too fast due to turbo modes. 970# 971config HARDLOCKUP_CHECK_TIMESTAMP 972 bool 973 974# 975# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 976# lockup detector rather than the perf based detector. 977# 978config HARDLOCKUP_DETECTOR 979 bool "Detect Hard Lockups" 980 depends on DEBUG_KERNEL && !S390 981 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 982 select LOCKUP_DETECTOR 983 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 984 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH 985 help 986 Say Y here to enable the kernel to act as a watchdog to detect 987 hard lockups. 988 989 Hardlockups are bugs that cause the CPU to loop in kernel mode 990 for more than 10 seconds, without letting other interrupts have a 991 chance to run. The current stack trace is displayed upon detection 992 and the system will stay locked up. 993 994config BOOTPARAM_HARDLOCKUP_PANIC 995 bool "Panic (Reboot) On Hard Lockups" 996 depends on HARDLOCKUP_DETECTOR 997 help 998 Say Y here to enable the kernel to panic on "hard lockups", 999 which are bugs that cause the kernel to loop in kernel 1000 mode with interrupts disabled for more than 10 seconds (configurable 1001 using the watchdog_thresh sysctl). 1002 1003 Say N if unsure. 1004 1005config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1006 int 1007 depends on HARDLOCKUP_DETECTOR 1008 range 0 1 1009 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1010 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1011 1012config DETECT_HUNG_TASK 1013 bool "Detect Hung Tasks" 1014 depends on DEBUG_KERNEL 1015 default SOFTLOCKUP_DETECTOR 1016 help 1017 Say Y here to enable the kernel to detect "hung tasks", 1018 which are bugs that cause the task to be stuck in 1019 uninterruptible "D" state indefinitely. 1020 1021 When a hung task is detected, the kernel will print the 1022 current stack trace (which you should report), but the 1023 task will stay in uninterruptible state. If lockdep is 1024 enabled then all held locks will also be reported. This 1025 feature has negligible overhead. 1026 1027config DEFAULT_HUNG_TASK_TIMEOUT 1028 int "Default timeout for hung task detection (in seconds)" 1029 depends on DETECT_HUNG_TASK 1030 default 120 1031 help 1032 This option controls the default timeout (in seconds) used 1033 to determine when a task has become non-responsive and should 1034 be considered hung. 1035 1036 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1037 sysctl or by writing a value to 1038 /proc/sys/kernel/hung_task_timeout_secs. 1039 1040 A timeout of 0 disables the check. The default is two minutes. 1041 Keeping the default should be fine in most cases. 1042 1043config BOOTPARAM_HUNG_TASK_PANIC 1044 bool "Panic (Reboot) On Hung Tasks" 1045 depends on DETECT_HUNG_TASK 1046 help 1047 Say Y here to enable the kernel to panic on "hung tasks", 1048 which are bugs that cause the kernel to leave a task stuck 1049 in uninterruptible "D" state. 1050 1051 The panic can be used in combination with panic_timeout, 1052 to cause the system to reboot automatically after a 1053 hung task has been detected. This feature is useful for 1054 high-availability systems that have uptime guarantees and 1055 where a hung tasks must be resolved ASAP. 1056 1057 Say N if unsure. 1058 1059config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1060 int 1061 depends on DETECT_HUNG_TASK 1062 range 0 1 1063 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1064 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1065 1066config WQ_WATCHDOG 1067 bool "Detect Workqueue Stalls" 1068 depends on DEBUG_KERNEL 1069 help 1070 Say Y here to enable stall detection on workqueues. If a 1071 worker pool doesn't make forward progress on a pending work 1072 item for over a given amount of time, 30s by default, a 1073 warning message is printed along with dump of workqueue 1074 state. This can be configured through kernel parameter 1075 "workqueue.watchdog_thresh" and its sysfs counterpart. 1076 1077config TEST_LOCKUP 1078 tristate "Test module to generate lockups" 1079 depends on m 1080 help 1081 This builds the "test_lockup" module that helps to make sure 1082 that watchdogs and lockup detectors are working properly. 1083 1084 Depending on module parameters it could emulate soft or hard 1085 lockup, "hung task", or locking arbitrary lock for a long time. 1086 Also it could generate series of lockups with cooling-down periods. 1087 1088 If unsure, say N. 1089 1090endmenu # "Debug lockups and hangs" 1091 1092menu "Scheduler Debugging" 1093 1094config SCHED_DEBUG 1095 bool "Collect scheduler debugging info" 1096 depends on DEBUG_KERNEL && PROC_FS 1097 default y 1098 help 1099 If you say Y here, the /proc/sched_debug file will be provided 1100 that can help debug the scheduler. The runtime overhead of this 1101 option is minimal. 1102 1103config SCHED_INFO 1104 bool 1105 default n 1106 1107config SCHEDSTATS 1108 bool "Collect scheduler statistics" 1109 depends on DEBUG_KERNEL && PROC_FS 1110 select SCHED_INFO 1111 help 1112 If you say Y here, additional code will be inserted into the 1113 scheduler and related routines to collect statistics about 1114 scheduler behavior and provide them in /proc/schedstat. These 1115 stats may be useful for both tuning and debugging the scheduler 1116 If you aren't debugging the scheduler or trying to tune a specific 1117 application, you can say N to avoid the very slight overhead 1118 this adds. 1119 1120endmenu 1121 1122config DEBUG_TIMEKEEPING 1123 bool "Enable extra timekeeping sanity checking" 1124 help 1125 This option will enable additional timekeeping sanity checks 1126 which may be helpful when diagnosing issues where timekeeping 1127 problems are suspected. 1128 1129 This may include checks in the timekeeping hotpaths, so this 1130 option may have a (very small) performance impact to some 1131 workloads. 1132 1133 If unsure, say N. 1134 1135config DEBUG_PREEMPT 1136 bool "Debug preemptible kernel" 1137 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1138 default y 1139 help 1140 If you say Y here then the kernel will use a debug variant of the 1141 commonly used smp_processor_id() function and will print warnings 1142 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1143 will detect preemption count underflows. 1144 1145menu "Lock Debugging (spinlocks, mutexes, etc...)" 1146 1147config LOCK_DEBUGGING_SUPPORT 1148 bool 1149 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1150 default y 1151 1152config PROVE_LOCKING 1153 bool "Lock debugging: prove locking correctness" 1154 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1155 select LOCKDEP 1156 select DEBUG_SPINLOCK 1157 select DEBUG_MUTEXES 1158 select DEBUG_RT_MUTEXES if RT_MUTEXES 1159 select DEBUG_RWSEMS 1160 select DEBUG_WW_MUTEX_SLOWPATH 1161 select DEBUG_LOCK_ALLOC 1162 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1163 select TRACE_IRQFLAGS 1164 default n 1165 help 1166 This feature enables the kernel to prove that all locking 1167 that occurs in the kernel runtime is mathematically 1168 correct: that under no circumstance could an arbitrary (and 1169 not yet triggered) combination of observed locking 1170 sequences (on an arbitrary number of CPUs, running an 1171 arbitrary number of tasks and interrupt contexts) cause a 1172 deadlock. 1173 1174 In short, this feature enables the kernel to report locking 1175 related deadlocks before they actually occur. 1176 1177 The proof does not depend on how hard and complex a 1178 deadlock scenario would be to trigger: how many 1179 participant CPUs, tasks and irq-contexts would be needed 1180 for it to trigger. The proof also does not depend on 1181 timing: if a race and a resulting deadlock is possible 1182 theoretically (no matter how unlikely the race scenario 1183 is), it will be proven so and will immediately be 1184 reported by the kernel (once the event is observed that 1185 makes the deadlock theoretically possible). 1186 1187 If a deadlock is impossible (i.e. the locking rules, as 1188 observed by the kernel, are mathematically correct), the 1189 kernel reports nothing. 1190 1191 NOTE: this feature can also be enabled for rwlocks, mutexes 1192 and rwsems - in which case all dependencies between these 1193 different locking variants are observed and mapped too, and 1194 the proof of observed correctness is also maintained for an 1195 arbitrary combination of these separate locking variants. 1196 1197 For more details, see Documentation/locking/lockdep-design.rst. 1198 1199config PROVE_RAW_LOCK_NESTING 1200 bool "Enable raw_spinlock - spinlock nesting checks" 1201 depends on PROVE_LOCKING 1202 default n 1203 help 1204 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1205 that the lock nesting rules for PREEMPT_RT enabled kernels are 1206 not violated. 1207 1208 NOTE: There are known nesting problems. So if you enable this 1209 option expect lockdep splats until these problems have been fully 1210 addressed which is work in progress. This config switch allows to 1211 identify and analyze these problems. It will be removed and the 1212 check permanentely enabled once the main issues have been fixed. 1213 1214 If unsure, select N. 1215 1216config LOCK_STAT 1217 bool "Lock usage statistics" 1218 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1219 select LOCKDEP 1220 select DEBUG_SPINLOCK 1221 select DEBUG_MUTEXES 1222 select DEBUG_RT_MUTEXES if RT_MUTEXES 1223 select DEBUG_LOCK_ALLOC 1224 default n 1225 help 1226 This feature enables tracking lock contention points 1227 1228 For more details, see Documentation/locking/lockstat.rst 1229 1230 This also enables lock events required by "perf lock", 1231 subcommand of perf. 1232 If you want to use "perf lock", you also need to turn on 1233 CONFIG_EVENT_TRACING. 1234 1235 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1236 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1237 1238config DEBUG_RT_MUTEXES 1239 bool "RT Mutex debugging, deadlock detection" 1240 depends on DEBUG_KERNEL && RT_MUTEXES 1241 help 1242 This allows rt mutex semantics violations and rt mutex related 1243 deadlocks (lockups) to be detected and reported automatically. 1244 1245config DEBUG_SPINLOCK 1246 bool "Spinlock and rw-lock debugging: basic checks" 1247 depends on DEBUG_KERNEL 1248 select UNINLINE_SPIN_UNLOCK 1249 help 1250 Say Y here and build SMP to catch missing spinlock initialization 1251 and certain other kinds of spinlock errors commonly made. This is 1252 best used in conjunction with the NMI watchdog so that spinlock 1253 deadlocks are also debuggable. 1254 1255config DEBUG_MUTEXES 1256 bool "Mutex debugging: basic checks" 1257 depends on DEBUG_KERNEL 1258 help 1259 This feature allows mutex semantics violations to be detected and 1260 reported. 1261 1262config DEBUG_WW_MUTEX_SLOWPATH 1263 bool "Wait/wound mutex debugging: Slowpath testing" 1264 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1265 select DEBUG_LOCK_ALLOC 1266 select DEBUG_SPINLOCK 1267 select DEBUG_MUTEXES 1268 help 1269 This feature enables slowpath testing for w/w mutex users by 1270 injecting additional -EDEADLK wound/backoff cases. Together with 1271 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1272 will test all possible w/w mutex interface abuse with the 1273 exception of simply not acquiring all the required locks. 1274 Note that this feature can introduce significant overhead, so 1275 it really should not be enabled in a production or distro kernel, 1276 even a debug kernel. If you are a driver writer, enable it. If 1277 you are a distro, do not. 1278 1279config DEBUG_RWSEMS 1280 bool "RW Semaphore debugging: basic checks" 1281 depends on DEBUG_KERNEL 1282 help 1283 This debugging feature allows mismatched rw semaphore locks 1284 and unlocks to be detected and reported. 1285 1286config DEBUG_LOCK_ALLOC 1287 bool "Lock debugging: detect incorrect freeing of live locks" 1288 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1289 select DEBUG_SPINLOCK 1290 select DEBUG_MUTEXES 1291 select DEBUG_RT_MUTEXES if RT_MUTEXES 1292 select LOCKDEP 1293 help 1294 This feature will check whether any held lock (spinlock, rwlock, 1295 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1296 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1297 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1298 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1299 held during task exit. 1300 1301config LOCKDEP 1302 bool 1303 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1304 select STACKTRACE 1305 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 1306 select KALLSYMS 1307 select KALLSYMS_ALL 1308 1309config LOCKDEP_SMALL 1310 bool 1311 1312config DEBUG_LOCKDEP 1313 bool "Lock dependency engine debugging" 1314 depends on DEBUG_KERNEL && LOCKDEP 1315 help 1316 If you say Y here, the lock dependency engine will do 1317 additional runtime checks to debug itself, at the price 1318 of more runtime overhead. 1319 1320config DEBUG_ATOMIC_SLEEP 1321 bool "Sleep inside atomic section checking" 1322 select PREEMPT_COUNT 1323 depends on DEBUG_KERNEL 1324 depends on !ARCH_NO_PREEMPT 1325 help 1326 If you say Y here, various routines which may sleep will become very 1327 noisy if they are called inside atomic sections: when a spinlock is 1328 held, inside an rcu read side critical section, inside preempt disabled 1329 sections, inside an interrupt, etc... 1330 1331config DEBUG_LOCKING_API_SELFTESTS 1332 bool "Locking API boot-time self-tests" 1333 depends on DEBUG_KERNEL 1334 help 1335 Say Y here if you want the kernel to run a short self-test during 1336 bootup. The self-test checks whether common types of locking bugs 1337 are detected by debugging mechanisms or not. (if you disable 1338 lock debugging then those bugs wont be detected of course.) 1339 The following locking APIs are covered: spinlocks, rwlocks, 1340 mutexes and rwsems. 1341 1342config LOCK_TORTURE_TEST 1343 tristate "torture tests for locking" 1344 depends on DEBUG_KERNEL 1345 select TORTURE_TEST 1346 help 1347 This option provides a kernel module that runs torture tests 1348 on kernel locking primitives. The kernel module may be built 1349 after the fact on the running kernel to be tested, if desired. 1350 1351 Say Y here if you want kernel locking-primitive torture tests 1352 to be built into the kernel. 1353 Say M if you want these torture tests to build as a module. 1354 Say N if you are unsure. 1355 1356config WW_MUTEX_SELFTEST 1357 tristate "Wait/wound mutex selftests" 1358 help 1359 This option provides a kernel module that runs tests on the 1360 on the struct ww_mutex locking API. 1361 1362 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1363 with this test harness. 1364 1365 Say M if you want these self tests to build as a module. 1366 Say N if you are unsure. 1367 1368config SCF_TORTURE_TEST 1369 tristate "torture tests for smp_call_function*()" 1370 depends on DEBUG_KERNEL 1371 select TORTURE_TEST 1372 help 1373 This option provides a kernel module that runs torture tests 1374 on the smp_call_function() family of primitives. The kernel 1375 module may be built after the fact on the running kernel to 1376 be tested, if desired. 1377 1378config CSD_LOCK_WAIT_DEBUG 1379 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1380 depends on DEBUG_KERNEL 1381 depends on 64BIT 1382 default n 1383 help 1384 This option enables debug prints when CPUs are slow to respond 1385 to the smp_call_function*() IPI wrappers. These debug prints 1386 include the IPI handler function currently executing (if any) 1387 and relevant stack traces. 1388 1389endmenu # lock debugging 1390 1391config TRACE_IRQFLAGS 1392 depends on TRACE_IRQFLAGS_SUPPORT 1393 bool 1394 help 1395 Enables hooks to interrupt enabling and disabling for 1396 either tracing or lock debugging. 1397 1398config TRACE_IRQFLAGS_NMI 1399 def_bool y 1400 depends on TRACE_IRQFLAGS 1401 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1402 1403config STACKTRACE 1404 bool "Stack backtrace support" 1405 depends on STACKTRACE_SUPPORT 1406 help 1407 This option causes the kernel to create a /proc/pid/stack for 1408 every process, showing its current stack trace. 1409 It is also used by various kernel debugging features that require 1410 stack trace generation. 1411 1412config WARN_ALL_UNSEEDED_RANDOM 1413 bool "Warn for all uses of unseeded randomness" 1414 default n 1415 help 1416 Some parts of the kernel contain bugs relating to their use of 1417 cryptographically secure random numbers before it's actually possible 1418 to generate those numbers securely. This setting ensures that these 1419 flaws don't go unnoticed, by enabling a message, should this ever 1420 occur. This will allow people with obscure setups to know when things 1421 are going wrong, so that they might contact developers about fixing 1422 it. 1423 1424 Unfortunately, on some models of some architectures getting 1425 a fully seeded CRNG is extremely difficult, and so this can 1426 result in dmesg getting spammed for a surprisingly long 1427 time. This is really bad from a security perspective, and 1428 so architecture maintainers really need to do what they can 1429 to get the CRNG seeded sooner after the system is booted. 1430 However, since users cannot do anything actionable to 1431 address this, by default the kernel will issue only a single 1432 warning for the first use of unseeded randomness. 1433 1434 Say Y here if you want to receive warnings for all uses of 1435 unseeded randomness. This will be of use primarily for 1436 those developers interested in improving the security of 1437 Linux kernels running on their architecture (or 1438 subarchitecture). 1439 1440config DEBUG_KOBJECT 1441 bool "kobject debugging" 1442 depends on DEBUG_KERNEL 1443 help 1444 If you say Y here, some extra kobject debugging messages will be sent 1445 to the syslog. 1446 1447config DEBUG_KOBJECT_RELEASE 1448 bool "kobject release debugging" 1449 depends on DEBUG_OBJECTS_TIMERS 1450 help 1451 kobjects are reference counted objects. This means that their 1452 last reference count put is not predictable, and the kobject can 1453 live on past the point at which a driver decides to drop it's 1454 initial reference to the kobject gained on allocation. An 1455 example of this would be a struct device which has just been 1456 unregistered. 1457 1458 However, some buggy drivers assume that after such an operation, 1459 the memory backing the kobject can be immediately freed. This 1460 goes completely against the principles of a refcounted object. 1461 1462 If you say Y here, the kernel will delay the release of kobjects 1463 on the last reference count to improve the visibility of this 1464 kind of kobject release bug. 1465 1466config HAVE_DEBUG_BUGVERBOSE 1467 bool 1468 1469menu "Debug kernel data structures" 1470 1471config DEBUG_LIST 1472 bool "Debug linked list manipulation" 1473 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1474 help 1475 Enable this to turn on extended checks in the linked-list 1476 walking routines. 1477 1478 If unsure, say N. 1479 1480config DEBUG_PLIST 1481 bool "Debug priority linked list manipulation" 1482 depends on DEBUG_KERNEL 1483 help 1484 Enable this to turn on extended checks in the priority-ordered 1485 linked-list (plist) walking routines. This checks the entire 1486 list multiple times during each manipulation. 1487 1488 If unsure, say N. 1489 1490config DEBUG_SG 1491 bool "Debug SG table operations" 1492 depends on DEBUG_KERNEL 1493 help 1494 Enable this to turn on checks on scatter-gather tables. This can 1495 help find problems with drivers that do not properly initialize 1496 their sg tables. 1497 1498 If unsure, say N. 1499 1500config DEBUG_NOTIFIERS 1501 bool "Debug notifier call chains" 1502 depends on DEBUG_KERNEL 1503 help 1504 Enable this to turn on sanity checking for notifier call chains. 1505 This is most useful for kernel developers to make sure that 1506 modules properly unregister themselves from notifier chains. 1507 This is a relatively cheap check but if you care about maximum 1508 performance, say N. 1509 1510config BUG_ON_DATA_CORRUPTION 1511 bool "Trigger a BUG when data corruption is detected" 1512 select DEBUG_LIST 1513 help 1514 Select this option if the kernel should BUG when it encounters 1515 data corruption in kernel memory structures when they get checked 1516 for validity. 1517 1518 If unsure, say N. 1519 1520endmenu 1521 1522config DEBUG_CREDENTIALS 1523 bool "Debug credential management" 1524 depends on DEBUG_KERNEL 1525 help 1526 Enable this to turn on some debug checking for credential 1527 management. The additional code keeps track of the number of 1528 pointers from task_structs to any given cred struct, and checks to 1529 see that this number never exceeds the usage count of the cred 1530 struct. 1531 1532 Furthermore, if SELinux is enabled, this also checks that the 1533 security pointer in the cred struct is never seen to be invalid. 1534 1535 If unsure, say N. 1536 1537source "kernel/rcu/Kconfig.debug" 1538 1539config DEBUG_WQ_FORCE_RR_CPU 1540 bool "Force round-robin CPU selection for unbound work items" 1541 depends on DEBUG_KERNEL 1542 default n 1543 help 1544 Workqueue used to implicitly guarantee that work items queued 1545 without explicit CPU specified are put on the local CPU. This 1546 guarantee is no longer true and while local CPU is still 1547 preferred work items may be put on foreign CPUs. Kernel 1548 parameter "workqueue.debug_force_rr_cpu" is added to force 1549 round-robin CPU selection to flush out usages which depend on the 1550 now broken guarantee. This config option enables the debug 1551 feature by default. When enabled, memory and cache locality will 1552 be impacted. 1553 1554config DEBUG_BLOCK_EXT_DEVT 1555 bool "Force extended block device numbers and spread them" 1556 depends on DEBUG_KERNEL 1557 depends on BLOCK 1558 default n 1559 help 1560 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON 1561 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT 1562 YOU ARE DOING. Distros, please enable this and fix whatever 1563 is broken. 1564 1565 Conventionally, block device numbers are allocated from 1566 predetermined contiguous area. However, extended block area 1567 may introduce non-contiguous block device numbers. This 1568 option forces most block device numbers to be allocated from 1569 the extended space and spreads them to discover kernel or 1570 userland code paths which assume predetermined contiguous 1571 device number allocation. 1572 1573 Note that turning on this debug option shuffles all the 1574 device numbers for all IDE and SCSI devices including libata 1575 ones, so root partition specified using device number 1576 directly (via rdev or root=MAJ:MIN) won't work anymore. 1577 Textual device names (root=/dev/sdXn) will continue to work. 1578 1579 Say N if you are unsure. 1580 1581config CPU_HOTPLUG_STATE_CONTROL 1582 bool "Enable CPU hotplug state control" 1583 depends on DEBUG_KERNEL 1584 depends on HOTPLUG_CPU 1585 default n 1586 help 1587 Allows to write steps between "offline" and "online" to the CPUs 1588 sysfs target file so states can be stepped granular. This is a debug 1589 option for now as the hotplug machinery cannot be stopped and 1590 restarted at arbitrary points yet. 1591 1592 Say N if your are unsure. 1593 1594config LATENCYTOP 1595 bool "Latency measuring infrastructure" 1596 depends on DEBUG_KERNEL 1597 depends on STACKTRACE_SUPPORT 1598 depends on PROC_FS 1599 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 1600 select KALLSYMS 1601 select KALLSYMS_ALL 1602 select STACKTRACE 1603 select SCHEDSTATS 1604 select SCHED_DEBUG 1605 help 1606 Enable this option if you want to use the LatencyTOP tool 1607 to find out which userspace is blocking on what kernel operations. 1608 1609source "kernel/trace/Kconfig" 1610 1611config PROVIDE_OHCI1394_DMA_INIT 1612 bool "Remote debugging over FireWire early on boot" 1613 depends on PCI && X86 1614 help 1615 If you want to debug problems which hang or crash the kernel early 1616 on boot and the crashing machine has a FireWire port, you can use 1617 this feature to remotely access the memory of the crashed machine 1618 over FireWire. This employs remote DMA as part of the OHCI1394 1619 specification which is now the standard for FireWire controllers. 1620 1621 With remote DMA, you can monitor the printk buffer remotely using 1622 firescope and access all memory below 4GB using fireproxy from gdb. 1623 Even controlling a kernel debugger is possible using remote DMA. 1624 1625 Usage: 1626 1627 If ohci1394_dma=early is used as boot parameter, it will initialize 1628 all OHCI1394 controllers which are found in the PCI config space. 1629 1630 As all changes to the FireWire bus such as enabling and disabling 1631 devices cause a bus reset and thereby disable remote DMA for all 1632 devices, be sure to have the cable plugged and FireWire enabled on 1633 the debugging host before booting the debug target for debugging. 1634 1635 This code (~1k) is freed after boot. By then, the firewire stack 1636 in charge of the OHCI-1394 controllers should be used instead. 1637 1638 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1639 1640source "samples/Kconfig" 1641 1642config ARCH_HAS_DEVMEM_IS_ALLOWED 1643 bool 1644 1645config STRICT_DEVMEM 1646 bool "Filter access to /dev/mem" 1647 depends on MMU && DEVMEM 1648 depends on ARCH_HAS_DEVMEM_IS_ALLOWED 1649 default y if PPC || X86 || ARM64 1650 help 1651 If this option is disabled, you allow userspace (root) access to all 1652 of memory, including kernel and userspace memory. Accidental 1653 access to this is obviously disastrous, but specific access can 1654 be used by people debugging the kernel. Note that with PAT support 1655 enabled, even in this case there are restrictions on /dev/mem 1656 use due to the cache aliasing requirements. 1657 1658 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1659 file only allows userspace access to PCI space and the BIOS code and 1660 data regions. This is sufficient for dosemu and X and all common 1661 users of /dev/mem. 1662 1663 If in doubt, say Y. 1664 1665config IO_STRICT_DEVMEM 1666 bool "Filter I/O access to /dev/mem" 1667 depends on STRICT_DEVMEM 1668 help 1669 If this option is disabled, you allow userspace (root) access to all 1670 io-memory regardless of whether a driver is actively using that 1671 range. Accidental access to this is obviously disastrous, but 1672 specific access can be used by people debugging kernel drivers. 1673 1674 If this option is switched on, the /dev/mem file only allows 1675 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1676 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1677 if the driver using a given range cannot be disabled. 1678 1679 If in doubt, say Y. 1680 1681menu "$(SRCARCH) Debugging" 1682 1683source "arch/$(SRCARCH)/Kconfig.debug" 1684 1685endmenu 1686 1687menu "Kernel Testing and Coverage" 1688 1689source "lib/kunit/Kconfig" 1690 1691config NOTIFIER_ERROR_INJECTION 1692 tristate "Notifier error injection" 1693 depends on DEBUG_KERNEL 1694 select DEBUG_FS 1695 help 1696 This option provides the ability to inject artificial errors to 1697 specified notifier chain callbacks. It is useful to test the error 1698 handling of notifier call chain failures. 1699 1700 Say N if unsure. 1701 1702config PM_NOTIFIER_ERROR_INJECT 1703 tristate "PM notifier error injection module" 1704 depends on PM && NOTIFIER_ERROR_INJECTION 1705 default m if PM_DEBUG 1706 help 1707 This option provides the ability to inject artificial errors to 1708 PM notifier chain callbacks. It is controlled through debugfs 1709 interface /sys/kernel/debug/notifier-error-inject/pm 1710 1711 If the notifier call chain should be failed with some events 1712 notified, write the error code to "actions/<notifier event>/error". 1713 1714 Example: Inject PM suspend error (-12 = -ENOMEM) 1715 1716 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1717 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1718 # echo mem > /sys/power/state 1719 bash: echo: write error: Cannot allocate memory 1720 1721 To compile this code as a module, choose M here: the module will 1722 be called pm-notifier-error-inject. 1723 1724 If unsure, say N. 1725 1726config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1727 tristate "OF reconfig notifier error injection module" 1728 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1729 help 1730 This option provides the ability to inject artificial errors to 1731 OF reconfig notifier chain callbacks. It is controlled 1732 through debugfs interface under 1733 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1734 1735 If the notifier call chain should be failed with some events 1736 notified, write the error code to "actions/<notifier event>/error". 1737 1738 To compile this code as a module, choose M here: the module will 1739 be called of-reconfig-notifier-error-inject. 1740 1741 If unsure, say N. 1742 1743config NETDEV_NOTIFIER_ERROR_INJECT 1744 tristate "Netdev notifier error injection module" 1745 depends on NET && NOTIFIER_ERROR_INJECTION 1746 help 1747 This option provides the ability to inject artificial errors to 1748 netdevice notifier chain callbacks. It is controlled through debugfs 1749 interface /sys/kernel/debug/notifier-error-inject/netdev 1750 1751 If the notifier call chain should be failed with some events 1752 notified, write the error code to "actions/<notifier event>/error". 1753 1754 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1755 1756 # cd /sys/kernel/debug/notifier-error-inject/netdev 1757 # echo -22 > actions/NETDEV_CHANGEMTU/error 1758 # ip link set eth0 mtu 1024 1759 RTNETLINK answers: Invalid argument 1760 1761 To compile this code as a module, choose M here: the module will 1762 be called netdev-notifier-error-inject. 1763 1764 If unsure, say N. 1765 1766config FUNCTION_ERROR_INJECTION 1767 def_bool y 1768 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1769 1770config FAULT_INJECTION 1771 bool "Fault-injection framework" 1772 depends on DEBUG_KERNEL 1773 help 1774 Provide fault-injection framework. 1775 For more details, see Documentation/fault-injection/. 1776 1777config FAILSLAB 1778 bool "Fault-injection capability for kmalloc" 1779 depends on FAULT_INJECTION 1780 depends on SLAB || SLUB 1781 help 1782 Provide fault-injection capability for kmalloc. 1783 1784config FAIL_PAGE_ALLOC 1785 bool "Fault-injection capability for alloc_pages()" 1786 depends on FAULT_INJECTION 1787 help 1788 Provide fault-injection capability for alloc_pages(). 1789 1790config FAULT_INJECTION_USERCOPY 1791 bool "Fault injection capability for usercopy functions" 1792 depends on FAULT_INJECTION 1793 help 1794 Provides fault-injection capability to inject failures 1795 in usercopy functions (copy_from_user(), get_user(), ...). 1796 1797config FAIL_MAKE_REQUEST 1798 bool "Fault-injection capability for disk IO" 1799 depends on FAULT_INJECTION && BLOCK 1800 help 1801 Provide fault-injection capability for disk IO. 1802 1803config FAIL_IO_TIMEOUT 1804 bool "Fault-injection capability for faking disk interrupts" 1805 depends on FAULT_INJECTION && BLOCK 1806 help 1807 Provide fault-injection capability on end IO handling. This 1808 will make the block layer "forget" an interrupt as configured, 1809 thus exercising the error handling. 1810 1811 Only works with drivers that use the generic timeout handling, 1812 for others it wont do anything. 1813 1814config FAIL_FUTEX 1815 bool "Fault-injection capability for futexes" 1816 select DEBUG_FS 1817 depends on FAULT_INJECTION && FUTEX 1818 help 1819 Provide fault-injection capability for futexes. 1820 1821config FAULT_INJECTION_DEBUG_FS 1822 bool "Debugfs entries for fault-injection capabilities" 1823 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1824 help 1825 Enable configuration of fault-injection capabilities via debugfs. 1826 1827config FAIL_FUNCTION 1828 bool "Fault-injection capability for functions" 1829 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1830 help 1831 Provide function-based fault-injection capability. 1832 This will allow you to override a specific function with a return 1833 with given return value. As a result, function caller will see 1834 an error value and have to handle it. This is useful to test the 1835 error handling in various subsystems. 1836 1837config FAIL_MMC_REQUEST 1838 bool "Fault-injection capability for MMC IO" 1839 depends on FAULT_INJECTION_DEBUG_FS && MMC 1840 help 1841 Provide fault-injection capability for MMC IO. 1842 This will make the mmc core return data errors. This is 1843 useful to test the error handling in the mmc block device 1844 and to test how the mmc host driver handles retries from 1845 the block device. 1846 1847config FAULT_INJECTION_STACKTRACE_FILTER 1848 bool "stacktrace filter for fault-injection capabilities" 1849 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1850 depends on !X86_64 1851 select STACKTRACE 1852 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 1853 help 1854 Provide stacktrace filter for fault-injection capabilities 1855 1856config ARCH_HAS_KCOV 1857 bool 1858 help 1859 An architecture should select this when it can successfully 1860 build and run with CONFIG_KCOV. This typically requires 1861 disabling instrumentation for some early boot code. 1862 1863config CC_HAS_SANCOV_TRACE_PC 1864 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1865 1866 1867config KCOV 1868 bool "Code coverage for fuzzing" 1869 depends on ARCH_HAS_KCOV 1870 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1871 select DEBUG_FS 1872 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1873 help 1874 KCOV exposes kernel code coverage information in a form suitable 1875 for coverage-guided fuzzing (randomized testing). 1876 1877 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1878 different machines and across reboots. If you need stable PC values, 1879 disable RANDOMIZE_BASE. 1880 1881 For more details, see Documentation/dev-tools/kcov.rst. 1882 1883config KCOV_ENABLE_COMPARISONS 1884 bool "Enable comparison operands collection by KCOV" 1885 depends on KCOV 1886 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 1887 help 1888 KCOV also exposes operands of every comparison in the instrumented 1889 code along with operand sizes and PCs of the comparison instructions. 1890 These operands can be used by fuzzing engines to improve the quality 1891 of fuzzing coverage. 1892 1893config KCOV_INSTRUMENT_ALL 1894 bool "Instrument all code by default" 1895 depends on KCOV 1896 default y 1897 help 1898 If you are doing generic system call fuzzing (like e.g. syzkaller), 1899 then you will want to instrument the whole kernel and you should 1900 say y here. If you are doing more targeted fuzzing (like e.g. 1901 filesystem fuzzing with AFL) then you will want to enable coverage 1902 for more specific subsets of files, and should say n here. 1903 1904config KCOV_IRQ_AREA_SIZE 1905 hex "Size of interrupt coverage collection area in words" 1906 depends on KCOV 1907 default 0x40000 1908 help 1909 KCOV uses preallocated per-cpu areas to collect coverage from 1910 soft interrupts. This specifies the size of those areas in the 1911 number of unsigned long words. 1912 1913menuconfig RUNTIME_TESTING_MENU 1914 bool "Runtime Testing" 1915 def_bool y 1916 1917if RUNTIME_TESTING_MENU 1918 1919config LKDTM 1920 tristate "Linux Kernel Dump Test Tool Module" 1921 depends on DEBUG_FS 1922 help 1923 This module enables testing of the different dumping mechanisms by 1924 inducing system failures at predefined crash points. 1925 If you don't need it: say N 1926 Choose M here to compile this code as a module. The module will be 1927 called lkdtm. 1928 1929 Documentation on how to use the module can be found in 1930 Documentation/fault-injection/provoke-crashes.rst 1931 1932config TEST_LIST_SORT 1933 tristate "Linked list sorting test" 1934 depends on DEBUG_KERNEL || m 1935 help 1936 Enable this to turn on 'list_sort()' function test. This test is 1937 executed only once during system boot (so affects only boot time), 1938 or at module load time. 1939 1940 If unsure, say N. 1941 1942config TEST_MIN_HEAP 1943 tristate "Min heap test" 1944 depends on DEBUG_KERNEL || m 1945 help 1946 Enable this to turn on min heap function tests. This test is 1947 executed only once during system boot (so affects only boot time), 1948 or at module load time. 1949 1950 If unsure, say N. 1951 1952config TEST_SORT 1953 tristate "Array-based sort test" 1954 depends on DEBUG_KERNEL || m 1955 help 1956 This option enables the self-test function of 'sort()' at boot, 1957 or at module load time. 1958 1959 If unsure, say N. 1960 1961config KPROBES_SANITY_TEST 1962 bool "Kprobes sanity tests" 1963 depends on DEBUG_KERNEL 1964 depends on KPROBES 1965 help 1966 This option provides for testing basic kprobes functionality on 1967 boot. Samples of kprobe and kretprobe are inserted and 1968 verified for functionality. 1969 1970 Say N if you are unsure. 1971 1972config BACKTRACE_SELF_TEST 1973 tristate "Self test for the backtrace code" 1974 depends on DEBUG_KERNEL 1975 help 1976 This option provides a kernel module that can be used to test 1977 the kernel stack backtrace code. This option is not useful 1978 for distributions or general kernels, but only for kernel 1979 developers working on architecture code. 1980 1981 Note that if you want to also test saved backtraces, you will 1982 have to enable STACKTRACE as well. 1983 1984 Say N if you are unsure. 1985 1986config RBTREE_TEST 1987 tristate "Red-Black tree test" 1988 depends on DEBUG_KERNEL 1989 help 1990 A benchmark measuring the performance of the rbtree library. 1991 Also includes rbtree invariant checks. 1992 1993config REED_SOLOMON_TEST 1994 tristate "Reed-Solomon library test" 1995 depends on DEBUG_KERNEL || m 1996 select REED_SOLOMON 1997 select REED_SOLOMON_ENC16 1998 select REED_SOLOMON_DEC16 1999 help 2000 This option enables the self-test function of rslib at boot, 2001 or at module load time. 2002 2003 If unsure, say N. 2004 2005config INTERVAL_TREE_TEST 2006 tristate "Interval tree test" 2007 depends on DEBUG_KERNEL 2008 select INTERVAL_TREE 2009 help 2010 A benchmark measuring the performance of the interval tree library 2011 2012config PERCPU_TEST 2013 tristate "Per cpu operations test" 2014 depends on m && DEBUG_KERNEL 2015 help 2016 Enable this option to build test module which validates per-cpu 2017 operations. 2018 2019 If unsure, say N. 2020 2021config ATOMIC64_SELFTEST 2022 tristate "Perform an atomic64_t self-test" 2023 help 2024 Enable this option to test the atomic64_t functions at boot or 2025 at module load time. 2026 2027 If unsure, say N. 2028 2029config ASYNC_RAID6_TEST 2030 tristate "Self test for hardware accelerated raid6 recovery" 2031 depends on ASYNC_RAID6_RECOV 2032 select ASYNC_MEMCPY 2033 help 2034 This is a one-shot self test that permutes through the 2035 recovery of all the possible two disk failure scenarios for a 2036 N-disk array. Recovery is performed with the asynchronous 2037 raid6 recovery routines, and will optionally use an offload 2038 engine if one is available. 2039 2040 If unsure, say N. 2041 2042config TEST_HEXDUMP 2043 tristate "Test functions located in the hexdump module at runtime" 2044 2045config TEST_STRING_HELPERS 2046 tristate "Test functions located in the string_helpers module at runtime" 2047 2048config TEST_STRSCPY 2049 tristate "Test strscpy*() family of functions at runtime" 2050 2051config TEST_KSTRTOX 2052 tristate "Test kstrto*() family of functions at runtime" 2053 2054config TEST_PRINTF 2055 tristate "Test printf() family of functions at runtime" 2056 2057config TEST_BITMAP 2058 tristate "Test bitmap_*() family of functions at runtime" 2059 help 2060 Enable this option to test the bitmap functions at boot. 2061 2062 If unsure, say N. 2063 2064config TEST_UUID 2065 tristate "Test functions located in the uuid module at runtime" 2066 2067config TEST_XARRAY 2068 tristate "Test the XArray code at runtime" 2069 2070config TEST_OVERFLOW 2071 tristate "Test check_*_overflow() functions at runtime" 2072 2073config TEST_RHASHTABLE 2074 tristate "Perform selftest on resizable hash table" 2075 help 2076 Enable this option to test the rhashtable functions at boot. 2077 2078 If unsure, say N. 2079 2080config TEST_HASH 2081 tristate "Perform selftest on hash functions" 2082 help 2083 Enable this option to test the kernel's integer (<linux/hash.h>), 2084 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) 2085 hash functions on boot (or module load). 2086 2087 This is intended to help people writing architecture-specific 2088 optimized versions. If unsure, say N. 2089 2090config TEST_IDA 2091 tristate "Perform selftest on IDA functions" 2092 2093config TEST_PARMAN 2094 tristate "Perform selftest on priority array manager" 2095 depends on PARMAN 2096 help 2097 Enable this option to test priority array manager on boot 2098 (or module load). 2099 2100 If unsure, say N. 2101 2102config TEST_IRQ_TIMINGS 2103 bool "IRQ timings selftest" 2104 depends on IRQ_TIMINGS 2105 help 2106 Enable this option to test the irq timings code on boot. 2107 2108 If unsure, say N. 2109 2110config TEST_LKM 2111 tristate "Test module loading with 'hello world' module" 2112 depends on m 2113 help 2114 This builds the "test_module" module that emits "Hello, world" 2115 on printk when loaded. It is designed to be used for basic 2116 evaluation of the module loading subsystem (for example when 2117 validating module verification). It lacks any extra dependencies, 2118 and will not normally be loaded by the system unless explicitly 2119 requested by name. 2120 2121 If unsure, say N. 2122 2123config TEST_BITOPS 2124 tristate "Test module for compilation of bitops operations" 2125 depends on m 2126 help 2127 This builds the "test_bitops" module that is much like the 2128 TEST_LKM module except that it does a basic exercise of the 2129 set/clear_bit macros and get_count_order/long to make sure there are 2130 no compiler warnings from C=1 sparse checker or -Wextra 2131 compilations. It has no dependencies and doesn't run or load unless 2132 explicitly requested by name. for example: modprobe test_bitops. 2133 2134 If unsure, say N. 2135 2136config TEST_VMALLOC 2137 tristate "Test module for stress/performance analysis of vmalloc allocator" 2138 default n 2139 depends on MMU 2140 depends on m 2141 help 2142 This builds the "test_vmalloc" module that should be used for 2143 stress and performance analysis. So, any new change for vmalloc 2144 subsystem can be evaluated from performance and stability point 2145 of view. 2146 2147 If unsure, say N. 2148 2149config TEST_USER_COPY 2150 tristate "Test user/kernel boundary protections" 2151 depends on m 2152 help 2153 This builds the "test_user_copy" module that runs sanity checks 2154 on the copy_to/from_user infrastructure, making sure basic 2155 user/kernel boundary testing is working. If it fails to load, 2156 a regression has been detected in the user/kernel memory boundary 2157 protections. 2158 2159 If unsure, say N. 2160 2161config TEST_BPF 2162 tristate "Test BPF filter functionality" 2163 depends on m && NET 2164 help 2165 This builds the "test_bpf" module that runs various test vectors 2166 against the BPF interpreter or BPF JIT compiler depending on the 2167 current setting. This is in particular useful for BPF JIT compiler 2168 development, but also to run regression tests against changes in 2169 the interpreter code. It also enables test stubs for eBPF maps and 2170 verifier used by user space verifier testsuite. 2171 2172 If unsure, say N. 2173 2174config TEST_BLACKHOLE_DEV 2175 tristate "Test blackhole netdev functionality" 2176 depends on m && NET 2177 help 2178 This builds the "test_blackhole_dev" module that validates the 2179 data path through this blackhole netdev. 2180 2181 If unsure, say N. 2182 2183config FIND_BIT_BENCHMARK 2184 tristate "Test find_bit functions" 2185 help 2186 This builds the "test_find_bit" module that measure find_*_bit() 2187 functions performance. 2188 2189 If unsure, say N. 2190 2191config TEST_FIRMWARE 2192 tristate "Test firmware loading via userspace interface" 2193 depends on FW_LOADER 2194 help 2195 This builds the "test_firmware" module that creates a userspace 2196 interface for testing firmware loading. This can be used to 2197 control the triggering of firmware loading without needing an 2198 actual firmware-using device. The contents can be rechecked by 2199 userspace. 2200 2201 If unsure, say N. 2202 2203config TEST_SYSCTL 2204 tristate "sysctl test driver" 2205 depends on PROC_SYSCTL 2206 help 2207 This builds the "test_sysctl" module. This driver enables to test the 2208 proc sysctl interfaces available to drivers safely without affecting 2209 production knobs which might alter system functionality. 2210 2211 If unsure, say N. 2212 2213config BITFIELD_KUNIT 2214 tristate "KUnit test bitfield functions at runtime" 2215 depends on KUNIT 2216 help 2217 Enable this option to test the bitfield functions at boot. 2218 2219 KUnit tests run during boot and output the results to the debug log 2220 in TAP format (http://testanything.org/). Only useful for kernel devs 2221 running the KUnit test harness, and not intended for inclusion into a 2222 production build. 2223 2224 For more information on KUnit and unit tests in general please refer 2225 to the KUnit documentation in Documentation/dev-tools/kunit/. 2226 2227 If unsure, say N. 2228 2229config SYSCTL_KUNIT_TEST 2230 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2231 depends on KUNIT 2232 default KUNIT_ALL_TESTS 2233 help 2234 This builds the proc sysctl unit test, which runs on boot. 2235 Tests the API contract and implementation correctness of sysctl. 2236 For more information on KUnit and unit tests in general please refer 2237 to the KUnit documentation in Documentation/dev-tools/kunit/. 2238 2239 If unsure, say N. 2240 2241config LIST_KUNIT_TEST 2242 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2243 depends on KUNIT 2244 default KUNIT_ALL_TESTS 2245 help 2246 This builds the linked list KUnit test suite. 2247 It tests that the API and basic functionality of the list_head type 2248 and associated macros. 2249 2250 KUnit tests run during boot and output the results to the debug log 2251 in TAP format (https://testanything.org/). Only useful for kernel devs 2252 running the KUnit test harness, and not intended for inclusion into a 2253 production build. 2254 2255 For more information on KUnit and unit tests in general please refer 2256 to the KUnit documentation in Documentation/dev-tools/kunit/. 2257 2258 If unsure, say N. 2259 2260config LINEAR_RANGES_TEST 2261 tristate "KUnit test for linear_ranges" 2262 depends on KUNIT 2263 select LINEAR_RANGES 2264 help 2265 This builds the linear_ranges unit test, which runs on boot. 2266 Tests the linear_ranges logic correctness. 2267 For more information on KUnit and unit tests in general please refer 2268 to the KUnit documentation in Documentation/dev-tools/kunit/. 2269 2270 If unsure, say N. 2271 2272config BITS_TEST 2273 tristate "KUnit test for bits.h" 2274 depends on KUNIT 2275 help 2276 This builds the bits unit test. 2277 Tests the logic of macros defined in bits.h. 2278 For more information on KUnit and unit tests in general please refer 2279 to the KUnit documentation in Documentation/dev-tools/kunit/. 2280 2281 If unsure, say N. 2282 2283config TEST_UDELAY 2284 tristate "udelay test driver" 2285 help 2286 This builds the "udelay_test" module that helps to make sure 2287 that udelay() is working properly. 2288 2289 If unsure, say N. 2290 2291config TEST_STATIC_KEYS 2292 tristate "Test static keys" 2293 depends on m 2294 help 2295 Test the static key interfaces. 2296 2297 If unsure, say N. 2298 2299config TEST_KMOD 2300 tristate "kmod stress tester" 2301 depends on m 2302 depends on NETDEVICES && NET_CORE && INET # for TUN 2303 depends on BLOCK 2304 select TEST_LKM 2305 select XFS_FS 2306 select TUN 2307 select BTRFS_FS 2308 help 2309 Test the kernel's module loading mechanism: kmod. kmod implements 2310 support to load modules using the Linux kernel's usermode helper. 2311 This test provides a series of tests against kmod. 2312 2313 Although technically you can either build test_kmod as a module or 2314 into the kernel we disallow building it into the kernel since 2315 it stress tests request_module() and this will very likely cause 2316 some issues by taking over precious threads available from other 2317 module load requests, ultimately this could be fatal. 2318 2319 To run tests run: 2320 2321 tools/testing/selftests/kmod/kmod.sh --help 2322 2323 If unsure, say N. 2324 2325config TEST_DEBUG_VIRTUAL 2326 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2327 depends on DEBUG_VIRTUAL 2328 help 2329 Test the kernel's ability to detect incorrect calls to 2330 virt_to_phys() done against the non-linear part of the 2331 kernel's virtual address map. 2332 2333 If unsure, say N. 2334 2335config TEST_MEMCAT_P 2336 tristate "Test memcat_p() helper function" 2337 help 2338 Test the memcat_p() helper for correctly merging two 2339 pointer arrays together. 2340 2341 If unsure, say N. 2342 2343config TEST_LIVEPATCH 2344 tristate "Test livepatching" 2345 default n 2346 depends on DYNAMIC_DEBUG 2347 depends on LIVEPATCH 2348 depends on m 2349 help 2350 Test kernel livepatching features for correctness. The tests will 2351 load test modules that will be livepatched in various scenarios. 2352 2353 To run all the livepatching tests: 2354 2355 make -C tools/testing/selftests TARGETS=livepatch run_tests 2356 2357 Alternatively, individual tests may be invoked: 2358 2359 tools/testing/selftests/livepatch/test-callbacks.sh 2360 tools/testing/selftests/livepatch/test-livepatch.sh 2361 tools/testing/selftests/livepatch/test-shadow-vars.sh 2362 2363 If unsure, say N. 2364 2365config TEST_OBJAGG 2366 tristate "Perform selftest on object aggreration manager" 2367 default n 2368 depends on OBJAGG 2369 help 2370 Enable this option to test object aggregation manager on boot 2371 (or module load). 2372 2373 2374config TEST_STACKINIT 2375 tristate "Test level of stack variable initialization" 2376 help 2377 Test if the kernel is zero-initializing stack variables and 2378 padding. Coverage is controlled by compiler flags, 2379 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2380 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2381 2382 If unsure, say N. 2383 2384config TEST_MEMINIT 2385 tristate "Test heap/page initialization" 2386 help 2387 Test if the kernel is zero-initializing heap and page allocations. 2388 This can be useful to test init_on_alloc and init_on_free features. 2389 2390 If unsure, say N. 2391 2392config TEST_HMM 2393 tristate "Test HMM (Heterogeneous Memory Management)" 2394 depends on TRANSPARENT_HUGEPAGE 2395 depends on DEVICE_PRIVATE 2396 select HMM_MIRROR 2397 select MMU_NOTIFIER 2398 help 2399 This is a pseudo device driver solely for testing HMM. 2400 Say M here if you want to build the HMM test module. 2401 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2402 2403 If unsure, say N. 2404 2405config TEST_FREE_PAGES 2406 tristate "Test freeing pages" 2407 help 2408 Test that a memory leak does not occur due to a race between 2409 freeing a block of pages and a speculative page reference. 2410 Loading this module is safe if your kernel has the bug fixed. 2411 If the bug is not fixed, it will leak gigabytes of memory and 2412 probably OOM your system. 2413 2414config TEST_FPU 2415 tristate "Test floating point operations in kernel space" 2416 depends on X86 && !KCOV_INSTRUMENT_ALL 2417 help 2418 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2419 which will trigger a sequence of floating point operations. This is used 2420 for self-testing floating point control register setting in 2421 kernel_fpu_begin(). 2422 2423 If unsure, say N. 2424 2425endif # RUNTIME_TESTING_MENU 2426 2427config MEMTEST 2428 bool "Memtest" 2429 help 2430 This option adds a kernel parameter 'memtest', which allows memtest 2431 to be set. 2432 memtest=0, mean disabled; -- default 2433 memtest=1, mean do 1 test pattern; 2434 ... 2435 memtest=17, mean do 17 test patterns. 2436 If you are unsure how to answer this question, answer N. 2437 2438 2439 2440config HYPERV_TESTING 2441 bool "Microsoft Hyper-V driver testing" 2442 default n 2443 depends on HYPERV && DEBUG_FS 2444 help 2445 Select this option to enable Hyper-V vmbus testing. 2446 2447endmenu # "Kernel Testing and Coverage" 2448 2449source "Documentation/Kconfig" 2450 2451endmenu # Kernel hacking 2452