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