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