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 PAHOLE_HAS_SPLIT_BTF 278 def_bool $(success, test `$(PAHOLE) --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/'` -ge "119") 279 280config DEBUG_INFO_BTF_MODULES 281 def_bool y 282 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF 283 help 284 Generate compact split BTF type information for kernel modules. 285 286config GDB_SCRIPTS 287 bool "Provide GDB scripts for kernel debugging" 288 help 289 This creates the required links to GDB helper scripts in the 290 build directory. If you load vmlinux into gdb, the helper 291 scripts will be automatically imported by gdb as well, and 292 additional functions are available to analyze a Linux kernel 293 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst 294 for further details. 295 296endif # DEBUG_INFO 297 298config ENABLE_MUST_CHECK 299 bool "Enable __must_check logic" 300 default y 301 help 302 Enable the __must_check logic in the kernel build. Disable this to 303 suppress the "warning: ignoring return value of 'foo', declared with 304 attribute warn_unused_result" messages. 305 306config FRAME_WARN 307 int "Warn for stack frames larger than" 308 range 0 8192 309 default 2048 if GCC_PLUGIN_LATENT_ENTROPY 310 default 1280 if (!64BIT && PARISC) 311 default 1024 if (!64BIT && !PARISC) 312 default 2048 if 64BIT 313 help 314 Tell gcc to warn at build time for stack frames larger than this. 315 Setting this too low will cause a lot of warnings. 316 Setting it to 0 disables the warning. 317 318config STRIP_ASM_SYMS 319 bool "Strip assembler-generated symbols during link" 320 default n 321 help 322 Strip internal assembler-generated symbols during a link (symbols 323 that look like '.Lxxx') so they don't pollute the output of 324 get_wchan() and suchlike. 325 326config READABLE_ASM 327 bool "Generate readable assembler code" 328 depends on DEBUG_KERNEL 329 help 330 Disable some compiler optimizations that tend to generate human unreadable 331 assembler output. This may make the kernel slightly slower, but it helps 332 to keep kernel developers who have to stare a lot at assembler listings 333 sane. 334 335config HEADERS_INSTALL 336 bool "Install uapi headers to usr/include" 337 depends on !UML 338 help 339 This option will install uapi headers (headers exported to user-space) 340 into the usr/include directory for use during the kernel build. 341 This is unneeded for building the kernel itself, but needed for some 342 user-space program samples. It is also needed by some features such 343 as uapi header sanity checks. 344 345config DEBUG_SECTION_MISMATCH 346 bool "Enable full Section mismatch analysis" 347 help 348 The section mismatch analysis checks if there are illegal 349 references from one section to another section. 350 During linktime or runtime, some sections are dropped; 351 any use of code/data previously in these sections would 352 most likely result in an oops. 353 In the code, functions and variables are annotated with 354 __init,, etc. (see the full list in include/linux/init.h), 355 which results in the code/data being placed in specific sections. 356 The section mismatch analysis is always performed after a full 357 kernel build, and enabling this option causes the following 358 additional step to occur: 359 - Add the option -fno-inline-functions-called-once to gcc commands. 360 When inlining a function annotated with __init in a non-init 361 function, we would lose the section information and thus 362 the analysis would not catch the illegal reference. 363 This option tells gcc to inline less (but it does result in 364 a larger kernel). 365 366config SECTION_MISMATCH_WARN_ONLY 367 bool "Make section mismatch errors non-fatal" 368 default y 369 help 370 If you say N here, the build process will fail if there are any 371 section mismatch, instead of just throwing warnings. 372 373 If unsure, say Y. 374 375config DEBUG_FORCE_FUNCTION_ALIGN_32B 376 bool "Force all function address 32B aligned" if EXPERT 377 help 378 There are cases that a commit from one domain changes the function 379 address alignment of other domains, and cause magic performance 380 bump (regression or improvement). Enable this option will help to 381 verify if the bump is caused by function alignment changes, while 382 it will slightly increase the kernel size and affect icache usage. 383 384 It is mainly for debug and performance tuning use. 385 386# 387# Select this config option from the architecture Kconfig, if it 388# is preferred to always offer frame pointers as a config 389# option on the architecture (regardless of KERNEL_DEBUG): 390# 391config ARCH_WANT_FRAME_POINTERS 392 bool 393 394config FRAME_POINTER 395 bool "Compile the kernel with frame pointers" 396 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS 397 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 398 help 399 If you say Y here the resulting kernel image will be slightly 400 larger and slower, but it gives very useful debugging information 401 in case of kernel bugs. (precise oopses/stacktraces/warnings) 402 403config STACK_VALIDATION 404 bool "Compile-time stack metadata validation" 405 depends on HAVE_STACK_VALIDATION 406 default n 407 help 408 Add compile-time checks to validate stack metadata, including frame 409 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure 410 that runtime stack traces are more reliable. 411 412 This is also a prerequisite for generation of ORC unwind data, which 413 is needed for CONFIG_UNWINDER_ORC. 414 415 For more information, see 416 tools/objtool/Documentation/stack-validation.txt. 417 418config VMLINUX_VALIDATION 419 bool 420 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT 421 default y 422 423config DEBUG_FORCE_WEAK_PER_CPU 424 bool "Force weak per-cpu definitions" 425 depends on DEBUG_KERNEL 426 help 427 s390 and alpha require percpu variables in modules to be 428 defined weak to work around addressing range issue which 429 puts the following two restrictions on percpu variable 430 definitions. 431 432 1. percpu symbols must be unique whether static or not 433 2. percpu variables can't be defined inside a function 434 435 To ensure that generic code follows the above rules, this 436 option forces all percpu variables to be defined as weak. 437 438endmenu # "Compiler options" 439 440menu "Generic Kernel Debugging Instruments" 441 442config MAGIC_SYSRQ 443 bool "Magic SysRq key" 444 depends on !UML 445 help 446 If you say Y here, you will have some control over the system even 447 if the system crashes for example during kernel debugging (e.g., you 448 will be able to flush the buffer cache to disk, reboot the system 449 immediately or dump some status information). This is accomplished 450 by pressing various keys while holding SysRq (Alt+PrintScreen). It 451 also works on a serial console (on PC hardware at least), if you 452 send a BREAK and then within 5 seconds a command keypress. The 453 keys are documented in <file:Documentation/admin-guide/sysrq.rst>. 454 Don't say Y unless you really know what this hack does. 455 456config MAGIC_SYSRQ_DEFAULT_ENABLE 457 hex "Enable magic SysRq key functions by default" 458 depends on MAGIC_SYSRQ 459 default 0x1 460 help 461 Specifies which SysRq key functions are enabled by default. 462 This may be set to 1 or 0 to enable or disable them all, or 463 to a bitmask as described in Documentation/admin-guide/sysrq.rst. 464 465config MAGIC_SYSRQ_SERIAL 466 bool "Enable magic SysRq key over serial" 467 depends on MAGIC_SYSRQ 468 default y 469 help 470 Many embedded boards have a disconnected TTL level serial which can 471 generate some garbage that can lead to spurious false sysrq detects. 472 This option allows you to decide whether you want to enable the 473 magic SysRq key. 474 475config MAGIC_SYSRQ_SERIAL_SEQUENCE 476 string "Char sequence that enables magic SysRq over serial" 477 depends on MAGIC_SYSRQ_SERIAL 478 default "" 479 help 480 Specifies a sequence of characters that can follow BREAK to enable 481 SysRq on a serial console. 482 483 If unsure, leave an empty string and the option will not be enabled. 484 485config DEBUG_FS 486 bool "Debug Filesystem" 487 help 488 debugfs is a virtual file system that kernel developers use to put 489 debugging files into. Enable this option to be able to read and 490 write to these files. 491 492 For detailed documentation on the debugfs API, see 493 Documentation/filesystems/. 494 495 If unsure, say N. 496 497choice 498 prompt "Debugfs default access" 499 depends on DEBUG_FS 500 default DEBUG_FS_ALLOW_ALL 501 help 502 This selects the default access restrictions for debugfs. 503 It can be overridden with kernel command line option 504 debugfs=[on,no-mount,off]. The restrictions apply for API access 505 and filesystem registration. 506 507config DEBUG_FS_ALLOW_ALL 508 bool "Access normal" 509 help 510 No restrictions apply. Both API and filesystem registration 511 is on. This is the normal default operation. 512 513config DEBUG_FS_DISALLOW_MOUNT 514 bool "Do not register debugfs as filesystem" 515 help 516 The API is open but filesystem is not loaded. Clients can still do 517 their work and read with debug tools that do not need 518 debugfs filesystem. 519 520config DEBUG_FS_ALLOW_NONE 521 bool "No access" 522 help 523 Access is off. Clients get -PERM when trying to create nodes in 524 debugfs tree and debugfs is not registered as a filesystem. 525 Client can then back-off or continue without debugfs access. 526 527endchoice 528 529source "lib/Kconfig.kgdb" 530source "lib/Kconfig.ubsan" 531source "lib/Kconfig.kcsan" 532 533endmenu 534 535config DEBUG_KERNEL 536 bool "Kernel debugging" 537 help 538 Say Y here if you are developing drivers or trying to debug and 539 identify kernel problems. 540 541config DEBUG_MISC 542 bool "Miscellaneous debug code" 543 default DEBUG_KERNEL 544 depends on DEBUG_KERNEL 545 help 546 Say Y here if you need to enable miscellaneous debug code that should 547 be under a more specific debug option but isn't. 548 549 550menu "Memory Debugging" 551 552source "mm/Kconfig.debug" 553 554config DEBUG_OBJECTS 555 bool "Debug object operations" 556 depends on DEBUG_KERNEL 557 help 558 If you say Y here, additional code will be inserted into the 559 kernel to track the life time of various objects and validate 560 the operations on those objects. 561 562config DEBUG_OBJECTS_SELFTEST 563 bool "Debug objects selftest" 564 depends on DEBUG_OBJECTS 565 help 566 This enables the selftest of the object debug code. 567 568config DEBUG_OBJECTS_FREE 569 bool "Debug objects in freed memory" 570 depends on DEBUG_OBJECTS 571 help 572 This enables checks whether a k/v free operation frees an area 573 which contains an object which has not been deactivated 574 properly. This can make kmalloc/kfree-intensive workloads 575 much slower. 576 577config DEBUG_OBJECTS_TIMERS 578 bool "Debug timer objects" 579 depends on DEBUG_OBJECTS 580 help 581 If you say Y here, additional code will be inserted into the 582 timer routines to track the life time of timer objects and 583 validate the timer operations. 584 585config DEBUG_OBJECTS_WORK 586 bool "Debug work objects" 587 depends on DEBUG_OBJECTS 588 help 589 If you say Y here, additional code will be inserted into the 590 work queue routines to track the life time of work objects and 591 validate the work operations. 592 593config DEBUG_OBJECTS_RCU_HEAD 594 bool "Debug RCU callbacks objects" 595 depends on DEBUG_OBJECTS 596 help 597 Enable this to turn on debugging of RCU list heads (call_rcu() usage). 598 599config DEBUG_OBJECTS_PERCPU_COUNTER 600 bool "Debug percpu counter objects" 601 depends on DEBUG_OBJECTS 602 help 603 If you say Y here, additional code will be inserted into the 604 percpu counter routines to track the life time of percpu counter 605 objects and validate the percpu counter operations. 606 607config DEBUG_OBJECTS_ENABLE_DEFAULT 608 int "debug_objects bootup default value (0-1)" 609 range 0 1 610 default "1" 611 depends on DEBUG_OBJECTS 612 help 613 Debug objects boot parameter default value 614 615config DEBUG_SLAB 616 bool "Debug slab memory allocations" 617 depends on DEBUG_KERNEL && SLAB 618 help 619 Say Y here to have the kernel do limited verification on memory 620 allocation as well as poisoning memory on free to catch use of freed 621 memory. This can make kmalloc/kfree-intensive workloads much slower. 622 623config SLUB_DEBUG_ON 624 bool "SLUB debugging on by default" 625 depends on SLUB && SLUB_DEBUG 626 default n 627 help 628 Boot with debugging on by default. SLUB boots by default with 629 the runtime debug capabilities switched off. Enabling this is 630 equivalent to specifying the "slub_debug" parameter on boot. 631 There is no support for more fine grained debug control like 632 possible with slub_debug=xxx. SLUB debugging may be switched 633 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 634 "slub_debug=-". 635 636config SLUB_STATS 637 default n 638 bool "Enable SLUB performance statistics" 639 depends on SLUB && SYSFS 640 help 641 SLUB statistics are useful to debug SLUBs allocation behavior in 642 order find ways to optimize the allocator. This should never be 643 enabled for production use since keeping statistics slows down 644 the allocator by a few percentage points. The slabinfo command 645 supports the determination of the most active slabs to figure 646 out which slabs are relevant to a particular load. 647 Try running: slabinfo -DA 648 649config HAVE_DEBUG_KMEMLEAK 650 bool 651 652config DEBUG_KMEMLEAK 653 bool "Kernel memory leak detector" 654 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK 655 select DEBUG_FS 656 select STACKTRACE if STACKTRACE_SUPPORT 657 select KALLSYMS 658 select CRC32 659 help 660 Say Y here if you want to enable the memory leak 661 detector. The memory allocation/freeing is traced in a way 662 similar to the Boehm's conservative garbage collector, the 663 difference being that the orphan objects are not freed but 664 only shown in /sys/kernel/debug/kmemleak. Enabling this 665 feature will introduce an overhead to memory 666 allocations. See Documentation/dev-tools/kmemleak.rst for more 667 details. 668 669 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 670 of finding leaks due to the slab objects poisoning. 671 672 In order to access the kmemleak file, debugfs needs to be 673 mounted (usually at /sys/kernel/debug). 674 675config DEBUG_KMEMLEAK_MEM_POOL_SIZE 676 int "Kmemleak memory pool size" 677 depends on DEBUG_KMEMLEAK 678 range 200 1000000 679 default 16000 680 help 681 Kmemleak must track all the memory allocations to avoid 682 reporting false positives. Since memory may be allocated or 683 freed before kmemleak is fully initialised, use a static pool 684 of metadata objects to track such callbacks. After kmemleak is 685 fully initialised, this memory pool acts as an emergency one 686 if slab allocations fail. 687 688config DEBUG_KMEMLEAK_TEST 689 tristate "Simple test for the kernel memory leak detector" 690 depends on DEBUG_KMEMLEAK && m 691 help 692 This option enables a module that explicitly leaks memory. 693 694 If unsure, say N. 695 696config DEBUG_KMEMLEAK_DEFAULT_OFF 697 bool "Default kmemleak to off" 698 depends on DEBUG_KMEMLEAK 699 help 700 Say Y here to disable kmemleak by default. It can then be enabled 701 on the command line via kmemleak=on. 702 703config DEBUG_KMEMLEAK_AUTO_SCAN 704 bool "Enable kmemleak auto scan thread on boot up" 705 default y 706 depends on DEBUG_KMEMLEAK 707 help 708 Depending on the cpu, kmemleak scan may be cpu intensive and can 709 stall user tasks at times. This option enables/disables automatic 710 kmemleak scan at boot up. 711 712 Say N here to disable kmemleak auto scan thread to stop automatic 713 scanning. Disabling this option disables automatic reporting of 714 memory leaks. 715 716 If unsure, say Y. 717 718config DEBUG_STACK_USAGE 719 bool "Stack utilization instrumentation" 720 depends on DEBUG_KERNEL && !IA64 721 help 722 Enables the display of the minimum amount of free stack which each 723 task has ever had available in the sysrq-T and sysrq-P debug output. 724 725 This option will slow down process creation somewhat. 726 727config SCHED_STACK_END_CHECK 728 bool "Detect stack corruption on calls to schedule()" 729 depends on DEBUG_KERNEL 730 default n 731 help 732 This option checks for a stack overrun on calls to schedule(). 733 If the stack end location is found to be over written always panic as 734 the content of the corrupted region can no longer be trusted. 735 This is to ensure no erroneous behaviour occurs which could result in 736 data corruption or a sporadic crash at a later stage once the region 737 is examined. The runtime overhead introduced is minimal. 738 739config ARCH_HAS_DEBUG_VM_PGTABLE 740 bool 741 help 742 An architecture should select this when it can successfully 743 build and run DEBUG_VM_PGTABLE. 744 745config DEBUG_VM 746 bool "Debug VM" 747 depends on DEBUG_KERNEL 748 help 749 Enable this to turn on extended checks in the virtual-memory system 750 that may impact performance. 751 752 If unsure, say N. 753 754config DEBUG_VM_VMACACHE 755 bool "Debug VMA caching" 756 depends on DEBUG_VM 757 help 758 Enable this to turn on VMA caching debug information. Doing so 759 can cause significant overhead, so only enable it in non-production 760 environments. 761 762 If unsure, say N. 763 764config DEBUG_VM_RB 765 bool "Debug VM red-black trees" 766 depends on DEBUG_VM 767 help 768 Enable VM red-black tree debugging information and extra validations. 769 770 If unsure, say N. 771 772config DEBUG_VM_PGFLAGS 773 bool "Debug page-flags operations" 774 depends on DEBUG_VM 775 help 776 Enables extra validation on page flags operations. 777 778 If unsure, say N. 779 780config DEBUG_VM_PGTABLE 781 bool "Debug arch page table for semantics compliance" 782 depends on MMU 783 depends on ARCH_HAS_DEBUG_VM_PGTABLE 784 default y if DEBUG_VM 785 help 786 This option provides a debug method which can be used to test 787 architecture page table helper functions on various platforms in 788 verifying if they comply with expected generic MM semantics. This 789 will help architecture code in making sure that any changes or 790 new additions of these helpers still conform to expected 791 semantics of the generic MM. Platforms will have to opt in for 792 this through ARCH_HAS_DEBUG_VM_PGTABLE. 793 794 If unsure, say N. 795 796config ARCH_HAS_DEBUG_VIRTUAL 797 bool 798 799config DEBUG_VIRTUAL 800 bool "Debug VM translations" 801 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL 802 help 803 Enable some costly sanity checks in virtual to page code. This can 804 catch mistakes with virt_to_page() and friends. 805 806 If unsure, say N. 807 808config DEBUG_NOMMU_REGIONS 809 bool "Debug the global anon/private NOMMU mapping region tree" 810 depends on DEBUG_KERNEL && !MMU 811 help 812 This option causes the global tree of anonymous and private mapping 813 regions to be regularly checked for invalid topology. 814 815config DEBUG_MEMORY_INIT 816 bool "Debug memory initialisation" if EXPERT 817 default !EXPERT 818 help 819 Enable this for additional checks during memory initialisation. 820 The sanity checks verify aspects of the VM such as the memory model 821 and other information provided by the architecture. Verbose 822 information will be printed at KERN_DEBUG loglevel depending 823 on the mminit_loglevel= command-line option. 824 825 If unsure, say Y 826 827config MEMORY_NOTIFIER_ERROR_INJECT 828 tristate "Memory hotplug notifier error injection module" 829 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION 830 help 831 This option provides the ability to inject artificial errors to 832 memory hotplug notifier chain callbacks. It is controlled through 833 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory 834 835 If the notifier call chain should be failed with some events 836 notified, write the error code to "actions/<notifier event>/error". 837 838 Example: Inject memory hotplug offline error (-12 == -ENOMEM) 839 840 # cd /sys/kernel/debug/notifier-error-inject/memory 841 # echo -12 > actions/MEM_GOING_OFFLINE/error 842 # echo offline > /sys/devices/system/memory/memoryXXX/state 843 bash: echo: write error: Cannot allocate memory 844 845 To compile this code as a module, choose M here: the module will 846 be called memory-notifier-error-inject. 847 848 If unsure, say N. 849 850config DEBUG_PER_CPU_MAPS 851 bool "Debug access to per_cpu maps" 852 depends on DEBUG_KERNEL 853 depends on SMP 854 help 855 Say Y to verify that the per_cpu map being accessed has 856 been set up. This adds a fair amount of code to kernel memory 857 and decreases performance. 858 859 Say N if unsure. 860 861config DEBUG_HIGHMEM 862 bool "Highmem debugging" 863 depends on DEBUG_KERNEL && HIGHMEM 864 help 865 This option enables additional error checking for high memory 866 systems. Disable for production systems. 867 868config HAVE_DEBUG_STACKOVERFLOW 869 bool 870 871config DEBUG_STACKOVERFLOW 872 bool "Check for stack overflows" 873 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW 874 help 875 Say Y here if you want to check for overflows of kernel, IRQ 876 and exception stacks (if your architecture uses them). This 877 option will show detailed messages if free stack space drops 878 below a certain limit. 879 880 These kinds of bugs usually occur when call-chains in the 881 kernel get too deep, especially when interrupts are 882 involved. 883 884 Use this in cases where you see apparently random memory 885 corruption, especially if it appears in 'struct thread_info' 886 887 If in doubt, say "N". 888 889source "lib/Kconfig.kasan" 890 891endmenu # "Memory Debugging" 892 893config DEBUG_SHIRQ 894 bool "Debug shared IRQ handlers" 895 depends on DEBUG_KERNEL 896 help 897 Enable this to generate a spurious interrupt just before a shared 898 interrupt handler is deregistered (generating one when registering 899 is currently disabled). Drivers need to handle this correctly. Some 900 don't and need to be caught. 901 902menu "Debug Oops, Lockups and Hangs" 903 904config PANIC_ON_OOPS 905 bool "Panic on Oops" 906 help 907 Say Y here to enable the kernel to panic when it oopses. This 908 has the same effect as setting oops=panic on the kernel command 909 line. 910 911 This feature is useful to ensure that the kernel does not do 912 anything erroneous after an oops which could result in data 913 corruption or other issues. 914 915 Say N if unsure. 916 917config PANIC_ON_OOPS_VALUE 918 int 919 range 0 1 920 default 0 if !PANIC_ON_OOPS 921 default 1 if PANIC_ON_OOPS 922 923config PANIC_TIMEOUT 924 int "panic timeout" 925 default 0 926 help 927 Set the timeout value (in seconds) until a reboot occurs when 928 the kernel panics. If n = 0, then we wait forever. A timeout 929 value n > 0 will wait n seconds before rebooting, while a timeout 930 value n < 0 will reboot immediately. 931 932config LOCKUP_DETECTOR 933 bool 934 935config SOFTLOCKUP_DETECTOR 936 bool "Detect Soft Lockups" 937 depends on DEBUG_KERNEL && !S390 938 select LOCKUP_DETECTOR 939 help 940 Say Y here to enable the kernel to act as a watchdog to detect 941 soft lockups. 942 943 Softlockups are bugs that cause the kernel to loop in kernel 944 mode for more than 20 seconds, without giving other tasks a 945 chance to run. The current stack trace is displayed upon 946 detection and the system will stay locked up. 947 948config BOOTPARAM_SOFTLOCKUP_PANIC 949 bool "Panic (Reboot) On Soft Lockups" 950 depends on SOFTLOCKUP_DETECTOR 951 help 952 Say Y here to enable the kernel to panic on "soft lockups", 953 which are bugs that cause the kernel to loop in kernel 954 mode for more than 20 seconds (configurable using the watchdog_thresh 955 sysctl), without giving other tasks a chance to run. 956 957 The panic can be used in combination with panic_timeout, 958 to cause the system to reboot automatically after a 959 lockup has been detected. This feature is useful for 960 high-availability systems that have uptime guarantees and 961 where a lockup must be resolved ASAP. 962 963 Say N if unsure. 964 965config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 966 int 967 depends on SOFTLOCKUP_DETECTOR 968 range 0 1 969 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 970 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 971 972config HARDLOCKUP_DETECTOR_PERF 973 bool 974 select SOFTLOCKUP_DETECTOR 975 976# 977# Enables a timestamp based low pass filter to compensate for perf based 978# hard lockup detection which runs too fast due to turbo modes. 979# 980config HARDLOCKUP_CHECK_TIMESTAMP 981 bool 982 983# 984# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard 985# lockup detector rather than the perf based detector. 986# 987config HARDLOCKUP_DETECTOR 988 bool "Detect Hard Lockups" 989 depends on DEBUG_KERNEL && !S390 990 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH 991 select LOCKUP_DETECTOR 992 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF 993 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH 994 help 995 Say Y here to enable the kernel to act as a watchdog to detect 996 hard lockups. 997 998 Hardlockups are bugs that cause the CPU to loop in kernel mode 999 for more than 10 seconds, without letting other interrupts have a 1000 chance to run. The current stack trace is displayed upon detection 1001 and the system will stay locked up. 1002 1003config BOOTPARAM_HARDLOCKUP_PANIC 1004 bool "Panic (Reboot) On Hard Lockups" 1005 depends on HARDLOCKUP_DETECTOR 1006 help 1007 Say Y here to enable the kernel to panic on "hard lockups", 1008 which are bugs that cause the kernel to loop in kernel 1009 mode with interrupts disabled for more than 10 seconds (configurable 1010 using the watchdog_thresh sysctl). 1011 1012 Say N if unsure. 1013 1014config BOOTPARAM_HARDLOCKUP_PANIC_VALUE 1015 int 1016 depends on HARDLOCKUP_DETECTOR 1017 range 0 1 1018 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC 1019 default 1 if BOOTPARAM_HARDLOCKUP_PANIC 1020 1021config DETECT_HUNG_TASK 1022 bool "Detect Hung Tasks" 1023 depends on DEBUG_KERNEL 1024 default SOFTLOCKUP_DETECTOR 1025 help 1026 Say Y here to enable the kernel to detect "hung tasks", 1027 which are bugs that cause the task to be stuck in 1028 uninterruptible "D" state indefinitely. 1029 1030 When a hung task is detected, the kernel will print the 1031 current stack trace (which you should report), but the 1032 task will stay in uninterruptible state. If lockdep is 1033 enabled then all held locks will also be reported. This 1034 feature has negligible overhead. 1035 1036config DEFAULT_HUNG_TASK_TIMEOUT 1037 int "Default timeout for hung task detection (in seconds)" 1038 depends on DETECT_HUNG_TASK 1039 default 120 1040 help 1041 This option controls the default timeout (in seconds) used 1042 to determine when a task has become non-responsive and should 1043 be considered hung. 1044 1045 It can be adjusted at runtime via the kernel.hung_task_timeout_secs 1046 sysctl or by writing a value to 1047 /proc/sys/kernel/hung_task_timeout_secs. 1048 1049 A timeout of 0 disables the check. The default is two minutes. 1050 Keeping the default should be fine in most cases. 1051 1052config BOOTPARAM_HUNG_TASK_PANIC 1053 bool "Panic (Reboot) On Hung Tasks" 1054 depends on DETECT_HUNG_TASK 1055 help 1056 Say Y here to enable the kernel to panic on "hung tasks", 1057 which are bugs that cause the kernel to leave a task stuck 1058 in uninterruptible "D" state. 1059 1060 The panic can be used in combination with panic_timeout, 1061 to cause the system to reboot automatically after a 1062 hung task has been detected. This feature is useful for 1063 high-availability systems that have uptime guarantees and 1064 where a hung tasks must be resolved ASAP. 1065 1066 Say N if unsure. 1067 1068config BOOTPARAM_HUNG_TASK_PANIC_VALUE 1069 int 1070 depends on DETECT_HUNG_TASK 1071 range 0 1 1072 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 1073 default 1 if BOOTPARAM_HUNG_TASK_PANIC 1074 1075config WQ_WATCHDOG 1076 bool "Detect Workqueue Stalls" 1077 depends on DEBUG_KERNEL 1078 help 1079 Say Y here to enable stall detection on workqueues. If a 1080 worker pool doesn't make forward progress on a pending work 1081 item for over a given amount of time, 30s by default, a 1082 warning message is printed along with dump of workqueue 1083 state. This can be configured through kernel parameter 1084 "workqueue.watchdog_thresh" and its sysfs counterpart. 1085 1086config TEST_LOCKUP 1087 tristate "Test module to generate lockups" 1088 depends on m 1089 help 1090 This builds the "test_lockup" module that helps to make sure 1091 that watchdogs and lockup detectors are working properly. 1092 1093 Depending on module parameters it could emulate soft or hard 1094 lockup, "hung task", or locking arbitrary lock for a long time. 1095 Also it could generate series of lockups with cooling-down periods. 1096 1097 If unsure, say N. 1098 1099endmenu # "Debug lockups and hangs" 1100 1101menu "Scheduler Debugging" 1102 1103config SCHED_DEBUG 1104 bool "Collect scheduler debugging info" 1105 depends on DEBUG_KERNEL && PROC_FS 1106 default y 1107 help 1108 If you say Y here, the /proc/sched_debug file will be provided 1109 that can help debug the scheduler. The runtime overhead of this 1110 option is minimal. 1111 1112config SCHED_INFO 1113 bool 1114 default n 1115 1116config SCHEDSTATS 1117 bool "Collect scheduler statistics" 1118 depends on DEBUG_KERNEL && PROC_FS 1119 select SCHED_INFO 1120 help 1121 If you say Y here, additional code will be inserted into the 1122 scheduler and related routines to collect statistics about 1123 scheduler behavior and provide them in /proc/schedstat. These 1124 stats may be useful for both tuning and debugging the scheduler 1125 If you aren't debugging the scheduler or trying to tune a specific 1126 application, you can say N to avoid the very slight overhead 1127 this adds. 1128 1129endmenu 1130 1131config DEBUG_TIMEKEEPING 1132 bool "Enable extra timekeeping sanity checking" 1133 help 1134 This option will enable additional timekeeping sanity checks 1135 which may be helpful when diagnosing issues where timekeeping 1136 problems are suspected. 1137 1138 This may include checks in the timekeeping hotpaths, so this 1139 option may have a (very small) performance impact to some 1140 workloads. 1141 1142 If unsure, say N. 1143 1144config DEBUG_PREEMPT 1145 bool "Debug preemptible kernel" 1146 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT 1147 default y 1148 help 1149 If you say Y here then the kernel will use a debug variant of the 1150 commonly used smp_processor_id() function and will print warnings 1151 if kernel code uses it in a preemption-unsafe way. Also, the kernel 1152 will detect preemption count underflows. 1153 1154menu "Lock Debugging (spinlocks, mutexes, etc...)" 1155 1156config LOCK_DEBUGGING_SUPPORT 1157 bool 1158 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 1159 default y 1160 1161config PROVE_LOCKING 1162 bool "Lock debugging: prove locking correctness" 1163 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1164 select LOCKDEP 1165 select DEBUG_SPINLOCK 1166 select DEBUG_MUTEXES 1167 select DEBUG_RT_MUTEXES if RT_MUTEXES 1168 select DEBUG_RWSEMS 1169 select DEBUG_WW_MUTEX_SLOWPATH 1170 select DEBUG_LOCK_ALLOC 1171 select PREEMPT_COUNT if !ARCH_NO_PREEMPT 1172 select TRACE_IRQFLAGS 1173 default n 1174 help 1175 This feature enables the kernel to prove that all locking 1176 that occurs in the kernel runtime is mathematically 1177 correct: that under no circumstance could an arbitrary (and 1178 not yet triggered) combination of observed locking 1179 sequences (on an arbitrary number of CPUs, running an 1180 arbitrary number of tasks and interrupt contexts) cause a 1181 deadlock. 1182 1183 In short, this feature enables the kernel to report locking 1184 related deadlocks before they actually occur. 1185 1186 The proof does not depend on how hard and complex a 1187 deadlock scenario would be to trigger: how many 1188 participant CPUs, tasks and irq-contexts would be needed 1189 for it to trigger. The proof also does not depend on 1190 timing: if a race and a resulting deadlock is possible 1191 theoretically (no matter how unlikely the race scenario 1192 is), it will be proven so and will immediately be 1193 reported by the kernel (once the event is observed that 1194 makes the deadlock theoretically possible). 1195 1196 If a deadlock is impossible (i.e. the locking rules, as 1197 observed by the kernel, are mathematically correct), the 1198 kernel reports nothing. 1199 1200 NOTE: this feature can also be enabled for rwlocks, mutexes 1201 and rwsems - in which case all dependencies between these 1202 different locking variants are observed and mapped too, and 1203 the proof of observed correctness is also maintained for an 1204 arbitrary combination of these separate locking variants. 1205 1206 For more details, see Documentation/locking/lockdep-design.rst. 1207 1208config PROVE_RAW_LOCK_NESTING 1209 bool "Enable raw_spinlock - spinlock nesting checks" 1210 depends on PROVE_LOCKING 1211 default n 1212 help 1213 Enable the raw_spinlock vs. spinlock nesting checks which ensure 1214 that the lock nesting rules for PREEMPT_RT enabled kernels are 1215 not violated. 1216 1217 NOTE: There are known nesting problems. So if you enable this 1218 option expect lockdep splats until these problems have been fully 1219 addressed which is work in progress. This config switch allows to 1220 identify and analyze these problems. It will be removed and the 1221 check permanentely enabled once the main issues have been fixed. 1222 1223 If unsure, select N. 1224 1225config LOCK_STAT 1226 bool "Lock usage statistics" 1227 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1228 select LOCKDEP 1229 select DEBUG_SPINLOCK 1230 select DEBUG_MUTEXES 1231 select DEBUG_RT_MUTEXES if RT_MUTEXES 1232 select DEBUG_LOCK_ALLOC 1233 default n 1234 help 1235 This feature enables tracking lock contention points 1236 1237 For more details, see Documentation/locking/lockstat.rst 1238 1239 This also enables lock events required by "perf lock", 1240 subcommand of perf. 1241 If you want to use "perf lock", you also need to turn on 1242 CONFIG_EVENT_TRACING. 1243 1244 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 1245 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 1246 1247config DEBUG_RT_MUTEXES 1248 bool "RT Mutex debugging, deadlock detection" 1249 depends on DEBUG_KERNEL && RT_MUTEXES 1250 help 1251 This allows rt mutex semantics violations and rt mutex related 1252 deadlocks (lockups) to be detected and reported automatically. 1253 1254config DEBUG_SPINLOCK 1255 bool "Spinlock and rw-lock debugging: basic checks" 1256 depends on DEBUG_KERNEL 1257 select UNINLINE_SPIN_UNLOCK 1258 help 1259 Say Y here and build SMP to catch missing spinlock initialization 1260 and certain other kinds of spinlock errors commonly made. This is 1261 best used in conjunction with the NMI watchdog so that spinlock 1262 deadlocks are also debuggable. 1263 1264config DEBUG_MUTEXES 1265 bool "Mutex debugging: basic checks" 1266 depends on DEBUG_KERNEL 1267 help 1268 This feature allows mutex semantics violations to be detected and 1269 reported. 1270 1271config DEBUG_WW_MUTEX_SLOWPATH 1272 bool "Wait/wound mutex debugging: Slowpath testing" 1273 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1274 select DEBUG_LOCK_ALLOC 1275 select DEBUG_SPINLOCK 1276 select DEBUG_MUTEXES 1277 help 1278 This feature enables slowpath testing for w/w mutex users by 1279 injecting additional -EDEADLK wound/backoff cases. Together with 1280 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this 1281 will test all possible w/w mutex interface abuse with the 1282 exception of simply not acquiring all the required locks. 1283 Note that this feature can introduce significant overhead, so 1284 it really should not be enabled in a production or distro kernel, 1285 even a debug kernel. If you are a driver writer, enable it. If 1286 you are a distro, do not. 1287 1288config DEBUG_RWSEMS 1289 bool "RW Semaphore debugging: basic checks" 1290 depends on DEBUG_KERNEL 1291 help 1292 This debugging feature allows mismatched rw semaphore locks 1293 and unlocks to be detected and reported. 1294 1295config DEBUG_LOCK_ALLOC 1296 bool "Lock debugging: detect incorrect freeing of live locks" 1297 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1298 select DEBUG_SPINLOCK 1299 select DEBUG_MUTEXES 1300 select DEBUG_RT_MUTEXES if RT_MUTEXES 1301 select LOCKDEP 1302 help 1303 This feature will check whether any held lock (spinlock, rwlock, 1304 mutex or rwsem) is incorrectly freed by the kernel, via any of the 1305 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 1306 vfree(), etc.), whether a live lock is incorrectly reinitialized via 1307 spin_lock_init()/mutex_init()/etc., or whether there is any lock 1308 held during task exit. 1309 1310config LOCKDEP 1311 bool 1312 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT 1313 select STACKTRACE 1314 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86 1315 select KALLSYMS 1316 select KALLSYMS_ALL 1317 1318config LOCKDEP_SMALL 1319 bool 1320 1321config DEBUG_LOCKDEP 1322 bool "Lock dependency engine debugging" 1323 depends on DEBUG_KERNEL && LOCKDEP 1324 help 1325 If you say Y here, the lock dependency engine will do 1326 additional runtime checks to debug itself, at the price 1327 of more runtime overhead. 1328 1329config DEBUG_ATOMIC_SLEEP 1330 bool "Sleep inside atomic section checking" 1331 select PREEMPT_COUNT 1332 depends on DEBUG_KERNEL 1333 depends on !ARCH_NO_PREEMPT 1334 help 1335 If you say Y here, various routines which may sleep will become very 1336 noisy if they are called inside atomic sections: when a spinlock is 1337 held, inside an rcu read side critical section, inside preempt disabled 1338 sections, inside an interrupt, etc... 1339 1340config DEBUG_LOCKING_API_SELFTESTS 1341 bool "Locking API boot-time self-tests" 1342 depends on DEBUG_KERNEL 1343 help 1344 Say Y here if you want the kernel to run a short self-test during 1345 bootup. The self-test checks whether common types of locking bugs 1346 are detected by debugging mechanisms or not. (if you disable 1347 lock debugging then those bugs wont be detected of course.) 1348 The following locking APIs are covered: spinlocks, rwlocks, 1349 mutexes and rwsems. 1350 1351config LOCK_TORTURE_TEST 1352 tristate "torture tests for locking" 1353 depends on DEBUG_KERNEL 1354 select TORTURE_TEST 1355 help 1356 This option provides a kernel module that runs torture tests 1357 on kernel locking primitives. The kernel module may be built 1358 after the fact on the running kernel to be tested, if desired. 1359 1360 Say Y here if you want kernel locking-primitive torture tests 1361 to be built into the kernel. 1362 Say M if you want these torture tests to build as a module. 1363 Say N if you are unsure. 1364 1365config WW_MUTEX_SELFTEST 1366 tristate "Wait/wound mutex selftests" 1367 help 1368 This option provides a kernel module that runs tests on the 1369 on the struct ww_mutex locking API. 1370 1371 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction 1372 with this test harness. 1373 1374 Say M if you want these self tests to build as a module. 1375 Say N if you are unsure. 1376 1377config SCF_TORTURE_TEST 1378 tristate "torture tests for smp_call_function*()" 1379 depends on DEBUG_KERNEL 1380 select TORTURE_TEST 1381 help 1382 This option provides a kernel module that runs torture tests 1383 on the smp_call_function() family of primitives. The kernel 1384 module may be built after the fact on the running kernel to 1385 be tested, if desired. 1386 1387config CSD_LOCK_WAIT_DEBUG 1388 bool "Debugging for csd_lock_wait(), called from smp_call_function*()" 1389 depends on DEBUG_KERNEL 1390 depends on 64BIT 1391 default n 1392 help 1393 This option enables debug prints when CPUs are slow to respond 1394 to the smp_call_function*() IPI wrappers. These debug prints 1395 include the IPI handler function currently executing (if any) 1396 and relevant stack traces. 1397 1398endmenu # lock debugging 1399 1400config TRACE_IRQFLAGS 1401 depends on TRACE_IRQFLAGS_SUPPORT 1402 bool 1403 help 1404 Enables hooks to interrupt enabling and disabling for 1405 either tracing or lock debugging. 1406 1407config TRACE_IRQFLAGS_NMI 1408 def_bool y 1409 depends on TRACE_IRQFLAGS 1410 depends on TRACE_IRQFLAGS_NMI_SUPPORT 1411 1412config STACKTRACE 1413 bool "Stack backtrace support" 1414 depends on STACKTRACE_SUPPORT 1415 help 1416 This option causes the kernel to create a /proc/pid/stack for 1417 every process, showing its current stack trace. 1418 It is also used by various kernel debugging features that require 1419 stack trace generation. 1420 1421config WARN_ALL_UNSEEDED_RANDOM 1422 bool "Warn for all uses of unseeded randomness" 1423 default n 1424 help 1425 Some parts of the kernel contain bugs relating to their use of 1426 cryptographically secure random numbers before it's actually possible 1427 to generate those numbers securely. This setting ensures that these 1428 flaws don't go unnoticed, by enabling a message, should this ever 1429 occur. This will allow people with obscure setups to know when things 1430 are going wrong, so that they might contact developers about fixing 1431 it. 1432 1433 Unfortunately, on some models of some architectures getting 1434 a fully seeded CRNG is extremely difficult, and so this can 1435 result in dmesg getting spammed for a surprisingly long 1436 time. This is really bad from a security perspective, and 1437 so architecture maintainers really need to do what they can 1438 to get the CRNG seeded sooner after the system is booted. 1439 However, since users cannot do anything actionable to 1440 address this, by default the kernel will issue only a single 1441 warning for the first use of unseeded randomness. 1442 1443 Say Y here if you want to receive warnings for all uses of 1444 unseeded randomness. This will be of use primarily for 1445 those developers interested in improving the security of 1446 Linux kernels running on their architecture (or 1447 subarchitecture). 1448 1449config DEBUG_KOBJECT 1450 bool "kobject debugging" 1451 depends on DEBUG_KERNEL 1452 help 1453 If you say Y here, some extra kobject debugging messages will be sent 1454 to the syslog. 1455 1456config DEBUG_KOBJECT_RELEASE 1457 bool "kobject release debugging" 1458 depends on DEBUG_OBJECTS_TIMERS 1459 help 1460 kobjects are reference counted objects. This means that their 1461 last reference count put is not predictable, and the kobject can 1462 live on past the point at which a driver decides to drop it's 1463 initial reference to the kobject gained on allocation. An 1464 example of this would be a struct device which has just been 1465 unregistered. 1466 1467 However, some buggy drivers assume that after such an operation, 1468 the memory backing the kobject can be immediately freed. This 1469 goes completely against the principles of a refcounted object. 1470 1471 If you say Y here, the kernel will delay the release of kobjects 1472 on the last reference count to improve the visibility of this 1473 kind of kobject release bug. 1474 1475config HAVE_DEBUG_BUGVERBOSE 1476 bool 1477 1478menu "Debug kernel data structures" 1479 1480config DEBUG_LIST 1481 bool "Debug linked list manipulation" 1482 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION 1483 help 1484 Enable this to turn on extended checks in the linked-list 1485 walking routines. 1486 1487 If unsure, say N. 1488 1489config DEBUG_PLIST 1490 bool "Debug priority linked list manipulation" 1491 depends on DEBUG_KERNEL 1492 help 1493 Enable this to turn on extended checks in the priority-ordered 1494 linked-list (plist) walking routines. This checks the entire 1495 list multiple times during each manipulation. 1496 1497 If unsure, say N. 1498 1499config DEBUG_SG 1500 bool "Debug SG table operations" 1501 depends on DEBUG_KERNEL 1502 help 1503 Enable this to turn on checks on scatter-gather tables. This can 1504 help find problems with drivers that do not properly initialize 1505 their sg tables. 1506 1507 If unsure, say N. 1508 1509config DEBUG_NOTIFIERS 1510 bool "Debug notifier call chains" 1511 depends on DEBUG_KERNEL 1512 help 1513 Enable this to turn on sanity checking for notifier call chains. 1514 This is most useful for kernel developers to make sure that 1515 modules properly unregister themselves from notifier chains. 1516 This is a relatively cheap check but if you care about maximum 1517 performance, say N. 1518 1519config BUG_ON_DATA_CORRUPTION 1520 bool "Trigger a BUG when data corruption is detected" 1521 select DEBUG_LIST 1522 help 1523 Select this option if the kernel should BUG when it encounters 1524 data corruption in kernel memory structures when they get checked 1525 for validity. 1526 1527 If unsure, say N. 1528 1529endmenu 1530 1531config DEBUG_CREDENTIALS 1532 bool "Debug credential management" 1533 depends on DEBUG_KERNEL 1534 help 1535 Enable this to turn on some debug checking for credential 1536 management. The additional code keeps track of the number of 1537 pointers from task_structs to any given cred struct, and checks to 1538 see that this number never exceeds the usage count of the cred 1539 struct. 1540 1541 Furthermore, if SELinux is enabled, this also checks that the 1542 security pointer in the cred struct is never seen to be invalid. 1543 1544 If unsure, say N. 1545 1546source "kernel/rcu/Kconfig.debug" 1547 1548config DEBUG_WQ_FORCE_RR_CPU 1549 bool "Force round-robin CPU selection for unbound work items" 1550 depends on DEBUG_KERNEL 1551 default n 1552 help 1553 Workqueue used to implicitly guarantee that work items queued 1554 without explicit CPU specified are put on the local CPU. This 1555 guarantee is no longer true and while local CPU is still 1556 preferred work items may be put on foreign CPUs. Kernel 1557 parameter "workqueue.debug_force_rr_cpu" is added to force 1558 round-robin CPU selection to flush out usages which depend on the 1559 now broken guarantee. This config option enables the debug 1560 feature by default. When enabled, memory and cache locality will 1561 be impacted. 1562 1563config DEBUG_BLOCK_EXT_DEVT 1564 bool "Force extended block device numbers and spread them" 1565 depends on DEBUG_KERNEL 1566 depends on BLOCK 1567 default n 1568 help 1569 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON 1570 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT 1571 YOU ARE DOING. Distros, please enable this and fix whatever 1572 is broken. 1573 1574 Conventionally, block device numbers are allocated from 1575 predetermined contiguous area. However, extended block area 1576 may introduce non-contiguous block device numbers. This 1577 option forces most block device numbers to be allocated from 1578 the extended space and spreads them to discover kernel or 1579 userland code paths which assume predetermined contiguous 1580 device number allocation. 1581 1582 Note that turning on this debug option shuffles all the 1583 device numbers for all IDE and SCSI devices including libata 1584 ones, so root partition specified using device number 1585 directly (via rdev or root=MAJ:MIN) won't work anymore. 1586 Textual device names (root=/dev/sdXn) will continue to work. 1587 1588 Say N if you are unsure. 1589 1590config CPU_HOTPLUG_STATE_CONTROL 1591 bool "Enable CPU hotplug state control" 1592 depends on DEBUG_KERNEL 1593 depends on HOTPLUG_CPU 1594 default n 1595 help 1596 Allows to write steps between "offline" and "online" to the CPUs 1597 sysfs target file so states can be stepped granular. This is a debug 1598 option for now as the hotplug machinery cannot be stopped and 1599 restarted at arbitrary points yet. 1600 1601 Say N if your are unsure. 1602 1603config LATENCYTOP 1604 bool "Latency measuring infrastructure" 1605 depends on DEBUG_KERNEL 1606 depends on STACKTRACE_SUPPORT 1607 depends on PROC_FS 1608 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 1609 select KALLSYMS 1610 select KALLSYMS_ALL 1611 select STACKTRACE 1612 select SCHEDSTATS 1613 select SCHED_DEBUG 1614 help 1615 Enable this option if you want to use the LatencyTOP tool 1616 to find out which userspace is blocking on what kernel operations. 1617 1618source "kernel/trace/Kconfig" 1619 1620config PROVIDE_OHCI1394_DMA_INIT 1621 bool "Remote debugging over FireWire early on boot" 1622 depends on PCI && X86 1623 help 1624 If you want to debug problems which hang or crash the kernel early 1625 on boot and the crashing machine has a FireWire port, you can use 1626 this feature to remotely access the memory of the crashed machine 1627 over FireWire. This employs remote DMA as part of the OHCI1394 1628 specification which is now the standard for FireWire controllers. 1629 1630 With remote DMA, you can monitor the printk buffer remotely using 1631 firescope and access all memory below 4GB using fireproxy from gdb. 1632 Even controlling a kernel debugger is possible using remote DMA. 1633 1634 Usage: 1635 1636 If ohci1394_dma=early is used as boot parameter, it will initialize 1637 all OHCI1394 controllers which are found in the PCI config space. 1638 1639 As all changes to the FireWire bus such as enabling and disabling 1640 devices cause a bus reset and thereby disable remote DMA for all 1641 devices, be sure to have the cable plugged and FireWire enabled on 1642 the debugging host before booting the debug target for debugging. 1643 1644 This code (~1k) is freed after boot. By then, the firewire stack 1645 in charge of the OHCI-1394 controllers should be used instead. 1646 1647 See Documentation/core-api/debugging-via-ohci1394.rst for more information. 1648 1649source "samples/Kconfig" 1650 1651config ARCH_HAS_DEVMEM_IS_ALLOWED 1652 bool 1653 1654config STRICT_DEVMEM 1655 bool "Filter access to /dev/mem" 1656 depends on MMU && DEVMEM 1657 depends on ARCH_HAS_DEVMEM_IS_ALLOWED 1658 default y if PPC || X86 || ARM64 1659 help 1660 If this option is disabled, you allow userspace (root) access to all 1661 of memory, including kernel and userspace memory. Accidental 1662 access to this is obviously disastrous, but specific access can 1663 be used by people debugging the kernel. Note that with PAT support 1664 enabled, even in this case there are restrictions on /dev/mem 1665 use due to the cache aliasing requirements. 1666 1667 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem 1668 file only allows userspace access to PCI space and the BIOS code and 1669 data regions. This is sufficient for dosemu and X and all common 1670 users of /dev/mem. 1671 1672 If in doubt, say Y. 1673 1674config IO_STRICT_DEVMEM 1675 bool "Filter I/O access to /dev/mem" 1676 depends on STRICT_DEVMEM 1677 help 1678 If this option is disabled, you allow userspace (root) access to all 1679 io-memory regardless of whether a driver is actively using that 1680 range. Accidental access to this is obviously disastrous, but 1681 specific access can be used by people debugging kernel drivers. 1682 1683 If this option is switched on, the /dev/mem file only allows 1684 userspace access to *idle* io-memory ranges (see /proc/iomem) This 1685 may break traditional users of /dev/mem (dosemu, legacy X, etc...) 1686 if the driver using a given range cannot be disabled. 1687 1688 If in doubt, say Y. 1689 1690menu "$(SRCARCH) Debugging" 1691 1692source "arch/$(SRCARCH)/Kconfig.debug" 1693 1694endmenu 1695 1696menu "Kernel Testing and Coverage" 1697 1698source "lib/kunit/Kconfig" 1699 1700config NOTIFIER_ERROR_INJECTION 1701 tristate "Notifier error injection" 1702 depends on DEBUG_KERNEL 1703 select DEBUG_FS 1704 help 1705 This option provides the ability to inject artificial errors to 1706 specified notifier chain callbacks. It is useful to test the error 1707 handling of notifier call chain failures. 1708 1709 Say N if unsure. 1710 1711config PM_NOTIFIER_ERROR_INJECT 1712 tristate "PM notifier error injection module" 1713 depends on PM && NOTIFIER_ERROR_INJECTION 1714 default m if PM_DEBUG 1715 help 1716 This option provides the ability to inject artificial errors to 1717 PM notifier chain callbacks. It is controlled through debugfs 1718 interface /sys/kernel/debug/notifier-error-inject/pm 1719 1720 If the notifier call chain should be failed with some events 1721 notified, write the error code to "actions/<notifier event>/error". 1722 1723 Example: Inject PM suspend error (-12 = -ENOMEM) 1724 1725 # cd /sys/kernel/debug/notifier-error-inject/pm/ 1726 # echo -12 > actions/PM_SUSPEND_PREPARE/error 1727 # echo mem > /sys/power/state 1728 bash: echo: write error: Cannot allocate memory 1729 1730 To compile this code as a module, choose M here: the module will 1731 be called pm-notifier-error-inject. 1732 1733 If unsure, say N. 1734 1735config OF_RECONFIG_NOTIFIER_ERROR_INJECT 1736 tristate "OF reconfig notifier error injection module" 1737 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION 1738 help 1739 This option provides the ability to inject artificial errors to 1740 OF reconfig notifier chain callbacks. It is controlled 1741 through debugfs interface under 1742 /sys/kernel/debug/notifier-error-inject/OF-reconfig/ 1743 1744 If the notifier call chain should be failed with some events 1745 notified, write the error code to "actions/<notifier event>/error". 1746 1747 To compile this code as a module, choose M here: the module will 1748 be called of-reconfig-notifier-error-inject. 1749 1750 If unsure, say N. 1751 1752config NETDEV_NOTIFIER_ERROR_INJECT 1753 tristate "Netdev notifier error injection module" 1754 depends on NET && NOTIFIER_ERROR_INJECTION 1755 help 1756 This option provides the ability to inject artificial errors to 1757 netdevice notifier chain callbacks. It is controlled through debugfs 1758 interface /sys/kernel/debug/notifier-error-inject/netdev 1759 1760 If the notifier call chain should be failed with some events 1761 notified, write the error code to "actions/<notifier event>/error". 1762 1763 Example: Inject netdevice mtu change error (-22 = -EINVAL) 1764 1765 # cd /sys/kernel/debug/notifier-error-inject/netdev 1766 # echo -22 > actions/NETDEV_CHANGEMTU/error 1767 # ip link set eth0 mtu 1024 1768 RTNETLINK answers: Invalid argument 1769 1770 To compile this code as a module, choose M here: the module will 1771 be called netdev-notifier-error-inject. 1772 1773 If unsure, say N. 1774 1775config FUNCTION_ERROR_INJECTION 1776 def_bool y 1777 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES 1778 1779config FAULT_INJECTION 1780 bool "Fault-injection framework" 1781 depends on DEBUG_KERNEL 1782 help 1783 Provide fault-injection framework. 1784 For more details, see Documentation/fault-injection/. 1785 1786config FAILSLAB 1787 bool "Fault-injection capability for kmalloc" 1788 depends on FAULT_INJECTION 1789 depends on SLAB || SLUB 1790 help 1791 Provide fault-injection capability for kmalloc. 1792 1793config FAIL_PAGE_ALLOC 1794 bool "Fault-injection capability for alloc_pages()" 1795 depends on FAULT_INJECTION 1796 help 1797 Provide fault-injection capability for alloc_pages(). 1798 1799config FAULT_INJECTION_USERCOPY 1800 bool "Fault injection capability for usercopy functions" 1801 depends on FAULT_INJECTION 1802 help 1803 Provides fault-injection capability to inject failures 1804 in usercopy functions (copy_from_user(), get_user(), ...). 1805 1806config FAIL_MAKE_REQUEST 1807 bool "Fault-injection capability for disk IO" 1808 depends on FAULT_INJECTION && BLOCK 1809 help 1810 Provide fault-injection capability for disk IO. 1811 1812config FAIL_IO_TIMEOUT 1813 bool "Fault-injection capability for faking disk interrupts" 1814 depends on FAULT_INJECTION && BLOCK 1815 help 1816 Provide fault-injection capability on end IO handling. This 1817 will make the block layer "forget" an interrupt as configured, 1818 thus exercising the error handling. 1819 1820 Only works with drivers that use the generic timeout handling, 1821 for others it wont do anything. 1822 1823config FAIL_FUTEX 1824 bool "Fault-injection capability for futexes" 1825 select DEBUG_FS 1826 depends on FAULT_INJECTION && FUTEX 1827 help 1828 Provide fault-injection capability for futexes. 1829 1830config FAULT_INJECTION_DEBUG_FS 1831 bool "Debugfs entries for fault-injection capabilities" 1832 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 1833 help 1834 Enable configuration of fault-injection capabilities via debugfs. 1835 1836config FAIL_FUNCTION 1837 bool "Fault-injection capability for functions" 1838 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION 1839 help 1840 Provide function-based fault-injection capability. 1841 This will allow you to override a specific function with a return 1842 with given return value. As a result, function caller will see 1843 an error value and have to handle it. This is useful to test the 1844 error handling in various subsystems. 1845 1846config FAIL_MMC_REQUEST 1847 bool "Fault-injection capability for MMC IO" 1848 depends on FAULT_INJECTION_DEBUG_FS && MMC 1849 help 1850 Provide fault-injection capability for MMC IO. 1851 This will make the mmc core return data errors. This is 1852 useful to test the error handling in the mmc block device 1853 and to test how the mmc host driver handles retries from 1854 the block device. 1855 1856config FAULT_INJECTION_STACKTRACE_FILTER 1857 bool "stacktrace filter for fault-injection capabilities" 1858 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 1859 depends on !X86_64 1860 select STACKTRACE 1861 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86 1862 help 1863 Provide stacktrace filter for fault-injection capabilities 1864 1865config ARCH_HAS_KCOV 1866 bool 1867 help 1868 An architecture should select this when it can successfully 1869 build and run with CONFIG_KCOV. This typically requires 1870 disabling instrumentation for some early boot code. 1871 1872config CC_HAS_SANCOV_TRACE_PC 1873 def_bool $(cc-option,-fsanitize-coverage=trace-pc) 1874 1875 1876config KCOV 1877 bool "Code coverage for fuzzing" 1878 depends on ARCH_HAS_KCOV 1879 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS 1880 select DEBUG_FS 1881 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC 1882 help 1883 KCOV exposes kernel code coverage information in a form suitable 1884 for coverage-guided fuzzing (randomized testing). 1885 1886 If RANDOMIZE_BASE is enabled, PC values will not be stable across 1887 different machines and across reboots. If you need stable PC values, 1888 disable RANDOMIZE_BASE. 1889 1890 For more details, see Documentation/dev-tools/kcov.rst. 1891 1892config KCOV_ENABLE_COMPARISONS 1893 bool "Enable comparison operands collection by KCOV" 1894 depends on KCOV 1895 depends on $(cc-option,-fsanitize-coverage=trace-cmp) 1896 help 1897 KCOV also exposes operands of every comparison in the instrumented 1898 code along with operand sizes and PCs of the comparison instructions. 1899 These operands can be used by fuzzing engines to improve the quality 1900 of fuzzing coverage. 1901 1902config KCOV_INSTRUMENT_ALL 1903 bool "Instrument all code by default" 1904 depends on KCOV 1905 default y 1906 help 1907 If you are doing generic system call fuzzing (like e.g. syzkaller), 1908 then you will want to instrument the whole kernel and you should 1909 say y here. If you are doing more targeted fuzzing (like e.g. 1910 filesystem fuzzing with AFL) then you will want to enable coverage 1911 for more specific subsets of files, and should say n here. 1912 1913config KCOV_IRQ_AREA_SIZE 1914 hex "Size of interrupt coverage collection area in words" 1915 depends on KCOV 1916 default 0x40000 1917 help 1918 KCOV uses preallocated per-cpu areas to collect coverage from 1919 soft interrupts. This specifies the size of those areas in the 1920 number of unsigned long words. 1921 1922menuconfig RUNTIME_TESTING_MENU 1923 bool "Runtime Testing" 1924 def_bool y 1925 1926if RUNTIME_TESTING_MENU 1927 1928config LKDTM 1929 tristate "Linux Kernel Dump Test Tool Module" 1930 depends on DEBUG_FS 1931 help 1932 This module enables testing of the different dumping mechanisms by 1933 inducing system failures at predefined crash points. 1934 If you don't need it: say N 1935 Choose M here to compile this code as a module. The module will be 1936 called lkdtm. 1937 1938 Documentation on how to use the module can be found in 1939 Documentation/fault-injection/provoke-crashes.rst 1940 1941config TEST_LIST_SORT 1942 tristate "Linked list sorting test" 1943 depends on DEBUG_KERNEL || m 1944 help 1945 Enable this to turn on 'list_sort()' function test. This test is 1946 executed only once during system boot (so affects only boot time), 1947 or at module load time. 1948 1949 If unsure, say N. 1950 1951config TEST_MIN_HEAP 1952 tristate "Min heap test" 1953 depends on DEBUG_KERNEL || m 1954 help 1955 Enable this to turn on min heap function tests. This test is 1956 executed only once during system boot (so affects only boot time), 1957 or at module load time. 1958 1959 If unsure, say N. 1960 1961config TEST_SORT 1962 tristate "Array-based sort test" 1963 depends on DEBUG_KERNEL || m 1964 help 1965 This option enables the self-test function of 'sort()' at boot, 1966 or at module load time. 1967 1968 If unsure, say N. 1969 1970config KPROBES_SANITY_TEST 1971 bool "Kprobes sanity tests" 1972 depends on DEBUG_KERNEL 1973 depends on KPROBES 1974 help 1975 This option provides for testing basic kprobes functionality on 1976 boot. Samples of kprobe and kretprobe are inserted and 1977 verified for functionality. 1978 1979 Say N if you are unsure. 1980 1981config BACKTRACE_SELF_TEST 1982 tristate "Self test for the backtrace code" 1983 depends on DEBUG_KERNEL 1984 help 1985 This option provides a kernel module that can be used to test 1986 the kernel stack backtrace code. This option is not useful 1987 for distributions or general kernels, but only for kernel 1988 developers working on architecture code. 1989 1990 Note that if you want to also test saved backtraces, you will 1991 have to enable STACKTRACE as well. 1992 1993 Say N if you are unsure. 1994 1995config RBTREE_TEST 1996 tristate "Red-Black tree test" 1997 depends on DEBUG_KERNEL 1998 help 1999 A benchmark measuring the performance of the rbtree library. 2000 Also includes rbtree invariant checks. 2001 2002config REED_SOLOMON_TEST 2003 tristate "Reed-Solomon library test" 2004 depends on DEBUG_KERNEL || m 2005 select REED_SOLOMON 2006 select REED_SOLOMON_ENC16 2007 select REED_SOLOMON_DEC16 2008 help 2009 This option enables the self-test function of rslib at boot, 2010 or at module load time. 2011 2012 If unsure, say N. 2013 2014config INTERVAL_TREE_TEST 2015 tristate "Interval tree test" 2016 depends on DEBUG_KERNEL 2017 select INTERVAL_TREE 2018 help 2019 A benchmark measuring the performance of the interval tree library 2020 2021config PERCPU_TEST 2022 tristate "Per cpu operations test" 2023 depends on m && DEBUG_KERNEL 2024 help 2025 Enable this option to build test module which validates per-cpu 2026 operations. 2027 2028 If unsure, say N. 2029 2030config ATOMIC64_SELFTEST 2031 tristate "Perform an atomic64_t self-test" 2032 help 2033 Enable this option to test the atomic64_t functions at boot or 2034 at module load time. 2035 2036 If unsure, say N. 2037 2038config ASYNC_RAID6_TEST 2039 tristate "Self test for hardware accelerated raid6 recovery" 2040 depends on ASYNC_RAID6_RECOV 2041 select ASYNC_MEMCPY 2042 help 2043 This is a one-shot self test that permutes through the 2044 recovery of all the possible two disk failure scenarios for a 2045 N-disk array. Recovery is performed with the asynchronous 2046 raid6 recovery routines, and will optionally use an offload 2047 engine if one is available. 2048 2049 If unsure, say N. 2050 2051config TEST_HEXDUMP 2052 tristate "Test functions located in the hexdump module at runtime" 2053 2054config TEST_STRING_HELPERS 2055 tristate "Test functions located in the string_helpers module at runtime" 2056 2057config TEST_STRSCPY 2058 tristate "Test strscpy*() family of functions at runtime" 2059 2060config TEST_KSTRTOX 2061 tristate "Test kstrto*() family of functions at runtime" 2062 2063config TEST_PRINTF 2064 tristate "Test printf() family of functions at runtime" 2065 2066config TEST_BITMAP 2067 tristate "Test bitmap_*() family of functions at runtime" 2068 help 2069 Enable this option to test the bitmap functions at boot. 2070 2071 If unsure, say N. 2072 2073config TEST_UUID 2074 tristate "Test functions located in the uuid module at runtime" 2075 2076config TEST_XARRAY 2077 tristate "Test the XArray code at runtime" 2078 2079config TEST_OVERFLOW 2080 tristate "Test check_*_overflow() functions at runtime" 2081 2082config TEST_RHASHTABLE 2083 tristate "Perform selftest on resizable hash table" 2084 help 2085 Enable this option to test the rhashtable functions at boot. 2086 2087 If unsure, say N. 2088 2089config TEST_HASH 2090 tristate "Perform selftest on hash functions" 2091 help 2092 Enable this option to test the kernel's integer (<linux/hash.h>), 2093 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>) 2094 hash functions on boot (or module load). 2095 2096 This is intended to help people writing architecture-specific 2097 optimized versions. If unsure, say N. 2098 2099config TEST_IDA 2100 tristate "Perform selftest on IDA functions" 2101 2102config TEST_PARMAN 2103 tristate "Perform selftest on priority array manager" 2104 depends on PARMAN 2105 help 2106 Enable this option to test priority array manager on boot 2107 (or module load). 2108 2109 If unsure, say N. 2110 2111config TEST_IRQ_TIMINGS 2112 bool "IRQ timings selftest" 2113 depends on IRQ_TIMINGS 2114 help 2115 Enable this option to test the irq timings code on boot. 2116 2117 If unsure, say N. 2118 2119config TEST_LKM 2120 tristate "Test module loading with 'hello world' module" 2121 depends on m 2122 help 2123 This builds the "test_module" module that emits "Hello, world" 2124 on printk when loaded. It is designed to be used for basic 2125 evaluation of the module loading subsystem (for example when 2126 validating module verification). It lacks any extra dependencies, 2127 and will not normally be loaded by the system unless explicitly 2128 requested by name. 2129 2130 If unsure, say N. 2131 2132config TEST_BITOPS 2133 tristate "Test module for compilation of bitops operations" 2134 depends on m 2135 help 2136 This builds the "test_bitops" module that is much like the 2137 TEST_LKM module except that it does a basic exercise of the 2138 set/clear_bit macros and get_count_order/long to make sure there are 2139 no compiler warnings from C=1 sparse checker or -Wextra 2140 compilations. It has no dependencies and doesn't run or load unless 2141 explicitly requested by name. for example: modprobe test_bitops. 2142 2143 If unsure, say N. 2144 2145config TEST_VMALLOC 2146 tristate "Test module for stress/performance analysis of vmalloc allocator" 2147 default n 2148 depends on MMU 2149 depends on m 2150 help 2151 This builds the "test_vmalloc" module that should be used for 2152 stress and performance analysis. So, any new change for vmalloc 2153 subsystem can be evaluated from performance and stability point 2154 of view. 2155 2156 If unsure, say N. 2157 2158config TEST_USER_COPY 2159 tristate "Test user/kernel boundary protections" 2160 depends on m 2161 help 2162 This builds the "test_user_copy" module that runs sanity checks 2163 on the copy_to/from_user infrastructure, making sure basic 2164 user/kernel boundary testing is working. If it fails to load, 2165 a regression has been detected in the user/kernel memory boundary 2166 protections. 2167 2168 If unsure, say N. 2169 2170config TEST_BPF 2171 tristate "Test BPF filter functionality" 2172 depends on m && NET 2173 help 2174 This builds the "test_bpf" module that runs various test vectors 2175 against the BPF interpreter or BPF JIT compiler depending on the 2176 current setting. This is in particular useful for BPF JIT compiler 2177 development, but also to run regression tests against changes in 2178 the interpreter code. It also enables test stubs for eBPF maps and 2179 verifier used by user space verifier testsuite. 2180 2181 If unsure, say N. 2182 2183config TEST_BLACKHOLE_DEV 2184 tristate "Test blackhole netdev functionality" 2185 depends on m && NET 2186 help 2187 This builds the "test_blackhole_dev" module that validates the 2188 data path through this blackhole netdev. 2189 2190 If unsure, say N. 2191 2192config FIND_BIT_BENCHMARK 2193 tristate "Test find_bit functions" 2194 help 2195 This builds the "test_find_bit" module that measure find_*_bit() 2196 functions performance. 2197 2198 If unsure, say N. 2199 2200config TEST_FIRMWARE 2201 tristate "Test firmware loading via userspace interface" 2202 depends on FW_LOADER 2203 help 2204 This builds the "test_firmware" module that creates a userspace 2205 interface for testing firmware loading. This can be used to 2206 control the triggering of firmware loading without needing an 2207 actual firmware-using device. The contents can be rechecked by 2208 userspace. 2209 2210 If unsure, say N. 2211 2212config TEST_SYSCTL 2213 tristate "sysctl test driver" 2214 depends on PROC_SYSCTL 2215 help 2216 This builds the "test_sysctl" module. This driver enables to test the 2217 proc sysctl interfaces available to drivers safely without affecting 2218 production knobs which might alter system functionality. 2219 2220 If unsure, say N. 2221 2222config BITFIELD_KUNIT 2223 tristate "KUnit test bitfield functions at runtime" 2224 depends on KUNIT 2225 help 2226 Enable this option to test the bitfield functions at boot. 2227 2228 KUnit tests run during boot and output the results to the debug log 2229 in TAP format (http://testanything.org/). Only useful for kernel devs 2230 running the KUnit test harness, and not intended for inclusion into a 2231 production build. 2232 2233 For more information on KUnit and unit tests in general please refer 2234 to the KUnit documentation in Documentation/dev-tools/kunit/. 2235 2236 If unsure, say N. 2237 2238config SYSCTL_KUNIT_TEST 2239 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS 2240 depends on KUNIT 2241 default KUNIT_ALL_TESTS 2242 help 2243 This builds the proc sysctl unit test, which runs on boot. 2244 Tests the API contract and implementation correctness of sysctl. 2245 For more information on KUnit and unit tests in general please refer 2246 to the KUnit documentation in Documentation/dev-tools/kunit/. 2247 2248 If unsure, say N. 2249 2250config LIST_KUNIT_TEST 2251 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS 2252 depends on KUNIT 2253 default KUNIT_ALL_TESTS 2254 help 2255 This builds the linked list KUnit test suite. 2256 It tests that the API and basic functionality of the list_head type 2257 and associated macros. 2258 2259 KUnit tests run during boot and output the results to the debug log 2260 in TAP format (https://testanything.org/). Only useful for kernel devs 2261 running the KUnit test harness, and not intended for inclusion into a 2262 production build. 2263 2264 For more information on KUnit and unit tests in general please refer 2265 to the KUnit documentation in Documentation/dev-tools/kunit/. 2266 2267 If unsure, say N. 2268 2269config LINEAR_RANGES_TEST 2270 tristate "KUnit test for linear_ranges" 2271 depends on KUNIT 2272 select LINEAR_RANGES 2273 help 2274 This builds the linear_ranges unit test, which runs on boot. 2275 Tests the linear_ranges logic correctness. 2276 For more information on KUnit and unit tests in general please refer 2277 to the KUnit documentation in Documentation/dev-tools/kunit/. 2278 2279 If unsure, say N. 2280 2281config BITS_TEST 2282 tristate "KUnit test for bits.h" 2283 depends on KUNIT 2284 help 2285 This builds the bits unit test. 2286 Tests the logic of macros defined in bits.h. 2287 For more information on KUnit and unit tests in general please refer 2288 to the KUnit documentation in Documentation/dev-tools/kunit/. 2289 2290 If unsure, say N. 2291 2292config TEST_UDELAY 2293 tristate "udelay test driver" 2294 help 2295 This builds the "udelay_test" module that helps to make sure 2296 that udelay() is working properly. 2297 2298 If unsure, say N. 2299 2300config TEST_STATIC_KEYS 2301 tristate "Test static keys" 2302 depends on m 2303 help 2304 Test the static key interfaces. 2305 2306 If unsure, say N. 2307 2308config TEST_KMOD 2309 tristate "kmod stress tester" 2310 depends on m 2311 depends on NETDEVICES && NET_CORE && INET # for TUN 2312 depends on BLOCK 2313 select TEST_LKM 2314 select XFS_FS 2315 select TUN 2316 select BTRFS_FS 2317 help 2318 Test the kernel's module loading mechanism: kmod. kmod implements 2319 support to load modules using the Linux kernel's usermode helper. 2320 This test provides a series of tests against kmod. 2321 2322 Although technically you can either build test_kmod as a module or 2323 into the kernel we disallow building it into the kernel since 2324 it stress tests request_module() and this will very likely cause 2325 some issues by taking over precious threads available from other 2326 module load requests, ultimately this could be fatal. 2327 2328 To run tests run: 2329 2330 tools/testing/selftests/kmod/kmod.sh --help 2331 2332 If unsure, say N. 2333 2334config TEST_DEBUG_VIRTUAL 2335 tristate "Test CONFIG_DEBUG_VIRTUAL feature" 2336 depends on DEBUG_VIRTUAL 2337 help 2338 Test the kernel's ability to detect incorrect calls to 2339 virt_to_phys() done against the non-linear part of the 2340 kernel's virtual address map. 2341 2342 If unsure, say N. 2343 2344config TEST_MEMCAT_P 2345 tristate "Test memcat_p() helper function" 2346 help 2347 Test the memcat_p() helper for correctly merging two 2348 pointer arrays together. 2349 2350 If unsure, say N. 2351 2352config TEST_LIVEPATCH 2353 tristate "Test livepatching" 2354 default n 2355 depends on DYNAMIC_DEBUG 2356 depends on LIVEPATCH 2357 depends on m 2358 help 2359 Test kernel livepatching features for correctness. The tests will 2360 load test modules that will be livepatched in various scenarios. 2361 2362 To run all the livepatching tests: 2363 2364 make -C tools/testing/selftests TARGETS=livepatch run_tests 2365 2366 Alternatively, individual tests may be invoked: 2367 2368 tools/testing/selftests/livepatch/test-callbacks.sh 2369 tools/testing/selftests/livepatch/test-livepatch.sh 2370 tools/testing/selftests/livepatch/test-shadow-vars.sh 2371 2372 If unsure, say N. 2373 2374config TEST_OBJAGG 2375 tristate "Perform selftest on object aggreration manager" 2376 default n 2377 depends on OBJAGG 2378 help 2379 Enable this option to test object aggregation manager on boot 2380 (or module load). 2381 2382 2383config TEST_STACKINIT 2384 tristate "Test level of stack variable initialization" 2385 help 2386 Test if the kernel is zero-initializing stack variables and 2387 padding. Coverage is controlled by compiler flags, 2388 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF, 2389 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL. 2390 2391 If unsure, say N. 2392 2393config TEST_MEMINIT 2394 tristate "Test heap/page initialization" 2395 help 2396 Test if the kernel is zero-initializing heap and page allocations. 2397 This can be useful to test init_on_alloc and init_on_free features. 2398 2399 If unsure, say N. 2400 2401config TEST_HMM 2402 tristate "Test HMM (Heterogeneous Memory Management)" 2403 depends on TRANSPARENT_HUGEPAGE 2404 depends on DEVICE_PRIVATE 2405 select HMM_MIRROR 2406 select MMU_NOTIFIER 2407 help 2408 This is a pseudo device driver solely for testing HMM. 2409 Say M here if you want to build the HMM test module. 2410 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests. 2411 2412 If unsure, say N. 2413 2414config TEST_FREE_PAGES 2415 tristate "Test freeing pages" 2416 help 2417 Test that a memory leak does not occur due to a race between 2418 freeing a block of pages and a speculative page reference. 2419 Loading this module is safe if your kernel has the bug fixed. 2420 If the bug is not fixed, it will leak gigabytes of memory and 2421 probably OOM your system. 2422 2423config TEST_FPU 2424 tristate "Test floating point operations in kernel space" 2425 depends on X86 && !KCOV_INSTRUMENT_ALL 2426 help 2427 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu 2428 which will trigger a sequence of floating point operations. This is used 2429 for self-testing floating point control register setting in 2430 kernel_fpu_begin(). 2431 2432 If unsure, say N. 2433 2434endif # RUNTIME_TESTING_MENU 2435 2436config MEMTEST 2437 bool "Memtest" 2438 help 2439 This option adds a kernel parameter 'memtest', which allows memtest 2440 to be set. 2441 memtest=0, mean disabled; -- default 2442 memtest=1, mean do 1 test pattern; 2443 ... 2444 memtest=17, mean do 17 test patterns. 2445 If you are unsure how to answer this question, answer N. 2446 2447 2448 2449config HYPERV_TESTING 2450 bool "Microsoft Hyper-V driver testing" 2451 default n 2452 depends on HYPERV && DEBUG_FS 2453 help 2454 Select this option to enable Hyper-V vmbus testing. 2455 2456endmenu # "Kernel Testing and Coverage" 2457 2458source "Documentation/Kconfig" 2459 2460endmenu # Kernel hacking 2461