lib/Kconfig.debug

   1 # SPDX-License-Identifier: GPL-2.0-only
   2 menu "Kernel hacking"
   3
   4 menu "printk and dmesg options"
   5
   6 config 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
  21 config 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
  38 config 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
  53 config 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
  64 config 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
  79 config 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
  97 config DYNAMIC_DEBUG
  98         bool "Enable dynamic printk() support"
  99         default n
 100         depends on PRINTK
 101         depends on (DEBUG_FS || PROC_FS)
 102         help
 103
 104           Compiles debug level messages into the kernel, which would not
 105           otherwise be available at runtime. These messages can then be
 106           enabled/disabled based on various levels of scope - per source file,
 107           function, module, format string, and line number. This mechanism
 108           implicitly compiles in all pr_debug() and dev_dbg() calls, which
 109           enlarges the kernel text size by about 2%.
 110
 111           If a source file is compiled with DEBUG flag set, any
 112           pr_debug() calls in it are enabled by default, but can be
 113           disabled at runtime as below.  Note that DEBUG flag is
 114           turned on by many CONFIG_*DEBUG* options.
 115
 116           Usage:
 117
 118           Dynamic debugging is controlled via the 'dynamic_debug/control' file,
 119           which is contained in the 'debugfs' filesystem or procfs.
 120           Thus, the debugfs or procfs filesystem must first be mounted before
 121           making use of this feature.
 122           We refer the control file as: <debugfs>/dynamic_debug/control. This
 123           file contains a list of the debug statements that can be enabled. The
 124           format for each line of the file is:
 125
 126                 filename:lineno [module]function flags format
 127
 128           filename : source file of the debug statement
 129           lineno : line number of the debug statement
 130           module : module that contains the debug statement
 131           function : function that contains the debug statement
 132           flags : '=p' means the line is turned 'on' for printing
 133           format : the format used for the debug statement
 134
 135           From a live system:
 136
 137                 nullarbor:~ # cat <debugfs>/dynamic_debug/control
 138                 # filename:lineno [module]function flags format
 139                 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
 140                 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
 141                 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
 142
 143           Example usage:
 144
 145                 // enable the message at line 1603 of file svcsock.c
 146                 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
 147                                                 <debugfs>/dynamic_debug/control
 148
 149                 // enable all the messages in file svcsock.c
 150                 nullarbor:~ # echo -n 'file svcsock.c +p' >
 151                                                 <debugfs>/dynamic_debug/control
 152
 153                 // enable all the messages in the NFS server module
 154                 nullarbor:~ # echo -n 'module nfsd +p' >
 155                                                 <debugfs>/dynamic_debug/control
 156
 157                 // enable all 12 messages in the function svc_process()
 158                 nullarbor:~ # echo -n 'func svc_process +p' >
 159                                                 <debugfs>/dynamic_debug/control
 160
 161                 // disable all 12 messages in the function svc_process()
 162                 nullarbor:~ # echo -n 'func svc_process -p' >
 163                                                 <debugfs>/dynamic_debug/control
 164
 165           See Documentation/admin-guide/dynamic-debug-howto.rst for additional
 166           information.
 167
 168 config SYMBOLIC_ERRNAME
 169         bool "Support symbolic error names in printf"
 170         default y if PRINTK
 171         help
 172           If you say Y here, the kernel's printf implementation will
 173           be able to print symbolic error names such as ENOSPC instead
 174           of the number 28. It makes the kernel image slightly larger
 175           (about 3KB), but can make the kernel logs easier to read.
 176
 177 config DEBUG_BUGVERBOSE
 178         bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
 179         depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
 180         default y
 181         help
 182           Say Y here to make BUG() panics output the file name and line number
 183           of the BUG call as well as the EIP and oops trace.  This aids
 184           debugging but costs about 70-100K of memory.
 185
 186 endmenu # "printk and dmesg options"
 187
 188 menu "Compile-time checks and compiler options"
 189
 190 config DEBUG_INFO
 191         bool "Compile the kernel with debug info"
 192         depends on DEBUG_KERNEL && !COMPILE_TEST
 193         help
 194           If you say Y here the resulting kernel image will include
 195           debugging info resulting in a larger kernel image.
 196           This adds debug symbols to the kernel and modules (gcc -g), and
 197           is needed if you intend to use kernel crashdump or binary object
 198           tools like crash, kgdb, LKCD, gdb, etc on the kernel.
 199           Say Y here only if you plan to debug the kernel.
 200
 201           If unsure, say N.
 202
 203 config DEBUG_INFO_REDUCED
 204         bool "Reduce debugging information"
 205         depends on DEBUG_INFO
 206         help
 207           If you say Y here gcc is instructed to generate less debugging
 208           information for structure types. This means that tools that
 209           need full debugging information (like kgdb or systemtap) won't
 210           be happy. But if you merely need debugging information to
 211           resolve line numbers there is no loss. Advantage is that
 212           build directory object sizes shrink dramatically over a full
 213           DEBUG_INFO build and compile times are reduced too.
 214           Only works with newer gcc versions.
 215
 216 config DEBUG_INFO_SPLIT
 217         bool "Produce split debuginfo in .dwo files"
 218         depends on DEBUG_INFO
 219         depends on $(cc-option,-gsplit-dwarf)
 220         help
 221           Generate debug info into separate .dwo files. This significantly
 222           reduces the build directory size for builds with DEBUG_INFO,
 223           because it stores the information only once on disk in .dwo
 224           files instead of multiple times in object files and executables.
 225           In addition the debug information is also compressed.
 226
 227           Requires recent gcc (4.7+) and recent gdb/binutils.
 228           Any tool that packages or reads debug information would need
 229           to know about the .dwo files and include them.
 230           Incompatible with older versions of ccache.
 231
 232 config DEBUG_INFO_DWARF4
 233         bool "Generate dwarf4 debuginfo"
 234         depends on DEBUG_INFO
 235         depends on $(cc-option,-gdwarf-4)
 236         help
 237           Generate dwarf4 debug info. This requires recent versions
 238           of gcc and gdb. It makes the debug information larger.
 239           But it significantly improves the success of resolving
 240           variables in gdb on optimized code.
 241
 242 config DEBUG_INFO_BTF
 243         bool "Generate BTF typeinfo"
 244         depends on DEBUG_INFO
 245         depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
 246         depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
 247         help
 248           Generate deduplicated BTF type information from DWARF debug info.
 249           Turning this on expects presence of pahole tool, which will convert
 250           DWARF type info into equivalent deduplicated BTF type info.
 251
 252 config GDB_SCRIPTS
 253         bool "Provide GDB scripts for kernel debugging"
 254         depends on DEBUG_INFO
 255         help
 256           This creates the required links to GDB helper scripts in the
 257           build directory. If you load vmlinux into gdb, the helper
 258           scripts will be automatically imported by gdb as well, and
 259           additional functions are available to analyze a Linux kernel
 260           instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
 261           for further details.
 262
 263 config ENABLE_MUST_CHECK
 264         bool "Enable __must_check logic"
 265         default y
 266         help
 267           Enable the __must_check logic in the kernel build.  Disable this to
 268           suppress the "warning: ignoring return value of 'foo', declared with
 269           attribute warn_unused_result" messages.
 270
 271 config FRAME_WARN
 272         int "Warn for stack frames larger than"
 273         range 0 8192
 274         default 2048 if GCC_PLUGIN_LATENT_ENTROPY
 275         default 1280 if (!64BIT && PARISC)
 276         default 1024 if (!64BIT && !PARISC)
 277         default 2048 if 64BIT
 278         help
 279           Tell gcc to warn at build time for stack frames larger than this.
 280           Setting this too low will cause a lot of warnings.
 281           Setting it to 0 disables the warning.
 282
 283 config STRIP_ASM_SYMS
 284         bool "Strip assembler-generated symbols during link"
 285         default n
 286         help
 287           Strip internal assembler-generated symbols during a link (symbols
 288           that look like '.Lxxx') so they don't pollute the output of
 289           get_wchan() and suchlike.
 290
 291 config READABLE_ASM
 292         bool "Generate readable assembler code"
 293         depends on DEBUG_KERNEL
 294         help
 295           Disable some compiler optimizations that tend to generate human unreadable
 296           assembler output. This may make the kernel slightly slower, but it helps
 297           to keep kernel developers who have to stare a lot at assembler listings
 298           sane.
 299
 300 config HEADERS_INSTALL
 301         bool "Install uapi headers to usr/include"
 302         depends on !UML
 303         help
 304           This option will install uapi headers (headers exported to user-space)
 305           into the usr/include directory for use during the kernel build.
 306           This is unneeded for building the kernel itself, but needed for some
 307           user-space program samples. It is also needed by some features such
 308           as uapi header sanity checks.
 309
 310 config DEBUG_SECTION_MISMATCH
 311         bool "Enable full Section mismatch analysis"
 312         help
 313           The section mismatch analysis checks if there are illegal
 314           references from one section to another section.
 315           During linktime or runtime, some sections are dropped;
 316           any use of code/data previously in these sections would
 317           most likely result in an oops.
 318           In the code, functions and variables are annotated with
 319           __init,, etc. (see the full list in include/linux/init.h),
 320           which results in the code/data being placed in specific sections.
 321           The section mismatch analysis is always performed after a full
 322           kernel build, and enabling this option causes the following
 323           additional step to occur:
 324           - Add the option -fno-inline-functions-called-once to gcc commands.
 325             When inlining a function annotated with __init in a non-init
 326             function, we would lose the section information and thus
 327             the analysis would not catch the illegal reference.
 328             This option tells gcc to inline less (but it does result in
 329             a larger kernel).
 330
 331 config SECTION_MISMATCH_WARN_ONLY
 332         bool "Make section mismatch errors non-fatal"
 333         default y
 334         help
 335           If you say N here, the build process will fail if there are any
 336           section mismatch, instead of just throwing warnings.
 337
 338           If unsure, say Y.
 339
 340 #
 341 # Select this config option from the architecture Kconfig, if it
 342 # is preferred to always offer frame pointers as a config
 343 # option on the architecture (regardless of KERNEL_DEBUG):
 344 #
 345 config ARCH_WANT_FRAME_POINTERS
 346         bool
 347
 348 config FRAME_POINTER
 349         bool "Compile the kernel with frame pointers"
 350         depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
 351         default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
 352         help
 353           If you say Y here the resulting kernel image will be slightly
 354           larger and slower, but it gives very useful debugging information
 355           in case of kernel bugs. (precise oopses/stacktraces/warnings)
 356
 357 config STACK_VALIDATION
 358         bool "Compile-time stack metadata validation"
 359         depends on HAVE_STACK_VALIDATION
 360         default n
 361         help
 362           Add compile-time checks to validate stack metadata, including frame
 363           pointers (if CONFIG_FRAME_POINTER is enabled).  This helps ensure
 364           that runtime stack traces are more reliable.
 365
 366           This is also a prerequisite for generation of ORC unwind data, which
 367           is needed for CONFIG_UNWINDER_ORC.
 368
 369           For more information, see
 370           tools/objtool/Documentation/stack-validation.txt.
 371
 372 config DEBUG_FORCE_WEAK_PER_CPU
 373         bool "Force weak per-cpu definitions"
 374         depends on DEBUG_KERNEL
 375         help
 376           s390 and alpha require percpu variables in modules to be
 377           defined weak to work around addressing range issue which
 378           puts the following two restrictions on percpu variable
 379           definitions.
 380
 381           1. percpu symbols must be unique whether static or not
 382           2. percpu variables can't be defined inside a function
 383
 384           To ensure that generic code follows the above rules, this
 385           option forces all percpu variables to be defined as weak.
 386
 387 endmenu # "Compiler options"
 388
 389 menu "Generic Kernel Debugging Instruments"
 390
 391 config MAGIC_SYSRQ
 392         bool "Magic SysRq key"
 393         depends on !UML
 394         help
 395           If you say Y here, you will have some control over the system even
 396           if the system crashes for example during kernel debugging (e.g., you
 397           will be able to flush the buffer cache to disk, reboot the system
 398           immediately or dump some status information). This is accomplished
 399           by pressing various keys while holding SysRq (Alt+PrintScreen). It
 400           also works on a serial console (on PC hardware at least), if you
 401           send a BREAK and then within 5 seconds a command keypress. The
 402           keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
 403           Don't say Y unless you really know what this hack does.
 404
 405 config MAGIC_SYSRQ_DEFAULT_ENABLE
 406         hex "Enable magic SysRq key functions by default"
 407         depends on MAGIC_SYSRQ
 408         default 0x1
 409         help
 410           Specifies which SysRq key functions are enabled by default.
 411           This may be set to 1 or 0 to enable or disable them all, or
 412           to a bitmask as described in Documentation/admin-guide/sysrq.rst.
 413
 414 config MAGIC_SYSRQ_SERIAL
 415         bool "Enable magic SysRq key over serial"
 416         depends on MAGIC_SYSRQ
 417         default y
 418         help
 419           Many embedded boards have a disconnected TTL level serial which can
 420           generate some garbage that can lead to spurious false sysrq detects.
 421           This option allows you to decide whether you want to enable the
 422           magic SysRq key.
 423
 424 config MAGIC_SYSRQ_SERIAL_SEQUENCE
 425         string "Char sequence that enables magic SysRq over serial"
 426         depends on MAGIC_SYSRQ_SERIAL
 427         default ""
 428         help
 429           Specifies a sequence of characters that can follow BREAK to enable
 430           SysRq on a serial console.
 431
 432           If unsure, leave an empty string and the option will not be enabled.
 433
 434 config DEBUG_FS
 435         bool "Debug Filesystem"
 436         help
 437           debugfs is a virtual file system that kernel developers use to put
 438           debugging files into.  Enable this option to be able to read and
 439           write to these files.
 440
 441           For detailed documentation on the debugfs API, see
 442           Documentation/filesystems/.
 443
 444           If unsure, say N.
 445
 446 source "lib/Kconfig.kgdb"
 447
 448 source "lib/Kconfig.ubsan"
 449
 450 endmenu
 451
 452 config DEBUG_KERNEL
 453         bool "Kernel debugging"
 454         help
 455           Say Y here if you are developing drivers or trying to debug and
 456           identify kernel problems.
 457
 458 config DEBUG_MISC
 459         bool "Miscellaneous debug code"
 460         default DEBUG_KERNEL
 461         depends on DEBUG_KERNEL
 462         help
 463           Say Y here if you need to enable miscellaneous debug code that should
 464           be under a more specific debug option but isn't.
 465
 466
 467 menu "Memory Debugging"
 468
 469 source "mm/Kconfig.debug"
 470
 471 config DEBUG_OBJECTS
 472         bool "Debug object operations"
 473         depends on DEBUG_KERNEL
 474         help
 475           If you say Y here, additional code will be inserted into the
 476           kernel to track the life time of various objects and validate
 477           the operations on those objects.
 478
 479 config DEBUG_OBJECTS_SELFTEST
 480         bool "Debug objects selftest"
 481         depends on DEBUG_OBJECTS
 482         help
 483           This enables the selftest of the object debug code.
 484
 485 config DEBUG_OBJECTS_FREE
 486         bool "Debug objects in freed memory"
 487         depends on DEBUG_OBJECTS
 488         help
 489           This enables checks whether a k/v free operation frees an area
 490           which contains an object which has not been deactivated
 491           properly. This can make kmalloc/kfree-intensive workloads
 492           much slower.
 493
 494 config DEBUG_OBJECTS_TIMERS
 495         bool "Debug timer objects"
 496         depends on DEBUG_OBJECTS
 497         help
 498           If you say Y here, additional code will be inserted into the
 499           timer routines to track the life time of timer objects and
 500           validate the timer operations.
 501
 502 config DEBUG_OBJECTS_WORK
 503         bool "Debug work objects"
 504         depends on DEBUG_OBJECTS
 505         help
 506           If you say Y here, additional code will be inserted into the
 507           work queue routines to track the life time of work objects and
 508           validate the work operations.
 509
 510 config DEBUG_OBJECTS_RCU_HEAD
 511         bool "Debug RCU callbacks objects"
 512         depends on DEBUG_OBJECTS
 513         help
 514           Enable this to turn on debugging of RCU list heads (call_rcu() usage).
 515
 516 config DEBUG_OBJECTS_PERCPU_COUNTER
 517         bool "Debug percpu counter objects"
 518         depends on DEBUG_OBJECTS
 519         help
 520           If you say Y here, additional code will be inserted into the
 521           percpu counter routines to track the life time of percpu counter
 522           objects and validate the percpu counter operations.
 523
 524 config DEBUG_OBJECTS_ENABLE_DEFAULT
 525         int "debug_objects bootup default value (0-1)"
 526         range 0 1
 527         default "1"
 528         depends on DEBUG_OBJECTS
 529         help
 530           Debug objects boot parameter default value
 531
 532 config DEBUG_SLAB
 533         bool "Debug slab memory allocations"
 534         depends on DEBUG_KERNEL && SLAB
 535         help
 536           Say Y here to have the kernel do limited verification on memory
 537           allocation as well as poisoning memory on free to catch use of freed
 538           memory. This can make kmalloc/kfree-intensive workloads much slower.
 539
 540 config SLUB_DEBUG_ON
 541         bool "SLUB debugging on by default"
 542         depends on SLUB && SLUB_DEBUG
 543         default n
 544         help
 545           Boot with debugging on by default. SLUB boots by default with
 546           the runtime debug capabilities switched off. Enabling this is
 547           equivalent to specifying the "slub_debug" parameter on boot.
 548           There is no support for more fine grained debug control like
 549           possible with slub_debug=xxx. SLUB debugging may be switched
 550           off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
 551           "slub_debug=-".
 552
 553 config SLUB_STATS
 554         default n
 555         bool "Enable SLUB performance statistics"
 556         depends on SLUB && SYSFS
 557         help
 558           SLUB statistics are useful to debug SLUBs allocation behavior in
 559           order find ways to optimize the allocator. This should never be
 560           enabled for production use since keeping statistics slows down
 561           the allocator by a few percentage points. The slabinfo command
 562           supports the determination of the most active slabs to figure
 563           out which slabs are relevant to a particular load.
 564           Try running: slabinfo -DA
 565
 566 config HAVE_DEBUG_KMEMLEAK
 567         bool
 568
 569 config DEBUG_KMEMLEAK
 570         bool "Kernel memory leak detector"
 571         depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
 572         select DEBUG_FS
 573         select STACKTRACE if STACKTRACE_SUPPORT
 574         select KALLSYMS
 575         select CRC32
 576         help
 577           Say Y here if you want to enable the memory leak
 578           detector. The memory allocation/freeing is traced in a way
 579           similar to the Boehm's conservative garbage collector, the
 580           difference being that the orphan objects are not freed but
 581           only shown in /sys/kernel/debug/kmemleak. Enabling this
 582           feature will introduce an overhead to memory
 583           allocations. See Documentation/dev-tools/kmemleak.rst for more
 584           details.
 585
 586           Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
 587           of finding leaks due to the slab objects poisoning.
 588
 589           In order to access the kmemleak file, debugfs needs to be
 590           mounted (usually at /sys/kernel/debug).
 591
 592 config DEBUG_KMEMLEAK_MEM_POOL_SIZE
 593         int "Kmemleak memory pool size"
 594         depends on DEBUG_KMEMLEAK
 595         range 200 1000000
 596         default 16000
 597         help
 598           Kmemleak must track all the memory allocations to avoid
 599           reporting false positives. Since memory may be allocated or
 600           freed before kmemleak is fully initialised, use a static pool
 601           of metadata objects to track such callbacks. After kmemleak is
 602           fully initialised, this memory pool acts as an emergency one
 603           if slab allocations fail.
 604
 605 config DEBUG_KMEMLEAK_TEST
 606         tristate "Simple test for the kernel memory leak detector"
 607         depends on DEBUG_KMEMLEAK && m
 608         help
 609           This option enables a module that explicitly leaks memory.
 610
 611           If unsure, say N.
 612
 613 config DEBUG_KMEMLEAK_DEFAULT_OFF
 614         bool "Default kmemleak to off"
 615         depends on DEBUG_KMEMLEAK
 616         help
 617           Say Y here to disable kmemleak by default. It can then be enabled
 618           on the command line via kmemleak=on.
 619
 620 config DEBUG_KMEMLEAK_AUTO_SCAN
 621         bool "Enable kmemleak auto scan thread on boot up"
 622         default y
 623         depends on DEBUG_KMEMLEAK
 624         help
 625           Depending on the cpu, kmemleak scan may be cpu intensive and can
 626           stall user tasks at times. This option enables/disables automatic
 627           kmemleak scan at boot up.
 628
 629           Say N here to disable kmemleak auto scan thread to stop automatic
 630           scanning. Disabling this option disables automatic reporting of
 631           memory leaks.
 632
 633           If unsure, say Y.
 634
 635 config DEBUG_STACK_USAGE
 636         bool "Stack utilization instrumentation"
 637         depends on DEBUG_KERNEL && !IA64
 638         help
 639           Enables the display of the minimum amount of free stack which each
 640           task has ever had available in the sysrq-T and sysrq-P debug output.
 641
 642           This option will slow down process creation somewhat.
 643
 644 config SCHED_STACK_END_CHECK
 645         bool "Detect stack corruption on calls to schedule()"
 646         depends on DEBUG_KERNEL
 647         default n
 648         help
 649           This option checks for a stack overrun on calls to schedule().
 650           If the stack end location is found to be over written always panic as
 651           the content of the corrupted region can no longer be trusted.
 652           This is to ensure no erroneous behaviour occurs which could result in
 653           data corruption or a sporadic crash at a later stage once the region
 654           is examined. The runtime overhead introduced is minimal.
 655
 656 config DEBUG_VM
 657         bool "Debug VM"
 658         depends on DEBUG_KERNEL
 659         help
 660           Enable this to turn on extended checks in the virtual-memory system
 661           that may impact performance.
 662
 663           If unsure, say N.
 664
 665 config DEBUG_VM_VMACACHE
 666         bool "Debug VMA caching"
 667         depends on DEBUG_VM
 668         help
 669           Enable this to turn on VMA caching debug information. Doing so
 670           can cause significant overhead, so only enable it in non-production
 671           environments.
 672
 673           If unsure, say N.
 674
 675 config DEBUG_VM_RB
 676         bool "Debug VM red-black trees"
 677         depends on DEBUG_VM
 678         help
 679           Enable VM red-black tree debugging information and extra validations.
 680
 681           If unsure, say N.
 682
 683 config DEBUG_VM_PGFLAGS
 684         bool "Debug page-flags operations"
 685         depends on DEBUG_VM
 686         help
 687           Enables extra validation on page flags operations.
 688
 689           If unsure, say N.
 690
 691 config ARCH_HAS_DEBUG_VIRTUAL
 692         bool
 693
 694 config DEBUG_VIRTUAL
 695         bool "Debug VM translations"
 696         depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
 697         help
 698           Enable some costly sanity checks in virtual to page code. This can
 699           catch mistakes with virt_to_page() and friends.
 700
 701           If unsure, say N.
 702
 703 config DEBUG_NOMMU_REGIONS
 704         bool "Debug the global anon/private NOMMU mapping region tree"
 705         depends on DEBUG_KERNEL && !MMU
 706         help
 707           This option causes the global tree of anonymous and private mapping
 708           regions to be regularly checked for invalid topology.
 709
 710 config DEBUG_MEMORY_INIT
 711         bool "Debug memory initialisation" if EXPERT
 712         default !EXPERT
 713         help
 714           Enable this for additional checks during memory initialisation.
 715           The sanity checks verify aspects of the VM such as the memory model
 716           and other information provided by the architecture. Verbose
 717           information will be printed at KERN_DEBUG loglevel depending
 718           on the mminit_loglevel= command-line option.
 719
 720           If unsure, say Y
 721
 722 config MEMORY_NOTIFIER_ERROR_INJECT
 723         tristate "Memory hotplug notifier error injection module"
 724         depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
 725         help
 726           This option provides the ability to inject artificial errors to
 727           memory hotplug notifier chain callbacks.  It is controlled through
 728           debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
 729
 730           If the notifier call chain should be failed with some events
 731           notified, write the error code to "actions/<notifier event>/error".
 732
 733           Example: Inject memory hotplug offline error (-12 == -ENOMEM)
 734
 735           # cd /sys/kernel/debug/notifier-error-inject/memory
 736           # echo -12 > actions/MEM_GOING_OFFLINE/error
 737           # echo offline > /sys/devices/system/memory/memoryXXX/state
 738           bash: echo: write error: Cannot allocate memory
 739
 740           To compile this code as a module, choose M here: the module will
 741           be called memory-notifier-error-inject.
 742
 743           If unsure, say N.
 744
 745 config DEBUG_PER_CPU_MAPS
 746         bool "Debug access to per_cpu maps"
 747         depends on DEBUG_KERNEL
 748         depends on SMP
 749         help
 750           Say Y to verify that the per_cpu map being accessed has
 751           been set up. This adds a fair amount of code to kernel memory
 752           and decreases performance.
 753
 754           Say N if unsure.
 755
 756 config DEBUG_HIGHMEM
 757         bool "Highmem debugging"
 758         depends on DEBUG_KERNEL && HIGHMEM
 759         help
 760           This option enables additional error checking for high memory
 761           systems.  Disable for production systems.
 762
 763 config HAVE_DEBUG_STACKOVERFLOW
 764         bool
 765
 766 config DEBUG_STACKOVERFLOW
 767         bool "Check for stack overflows"
 768         depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
 769         ---help---
 770           Say Y here if you want to check for overflows of kernel, IRQ
 771           and exception stacks (if your architecture uses them). This
 772           option will show detailed messages if free stack space drops
 773           below a certain limit.
 774
 775           These kinds of bugs usually occur when call-chains in the
 776           kernel get too deep, especially when interrupts are
 777           involved.
 778
 779           Use this in cases where you see apparently random memory
 780           corruption, especially if it appears in 'struct thread_info'
 781
 782           If in doubt, say "N".
 783
 784 source "lib/Kconfig.kasan"
 785
 786 endmenu # "Memory Debugging"
 787
 788 config DEBUG_SHIRQ
 789         bool "Debug shared IRQ handlers"
 790         depends on DEBUG_KERNEL
 791         help
 792           Enable this to generate a spurious interrupt as soon as a shared
 793           interrupt handler is registered, and just before one is deregistered.
 794           Drivers ought to be able to handle interrupts coming in at those
 795           points; some don't and need to be caught.
 796
 797 menu "Debug Oops, Lockups and Hangs"
 798
 799 config PANIC_ON_OOPS
 800         bool "Panic on Oops"
 801         help
 802           Say Y here to enable the kernel to panic when it oopses. This
 803           has the same effect as setting oops=panic on the kernel command
 804           line.
 805
 806           This feature is useful to ensure that the kernel does not do
 807           anything erroneous after an oops which could result in data
 808           corruption or other issues.
 809
 810           Say N if unsure.
 811
 812 config PANIC_ON_OOPS_VALUE
 813         int
 814         range 0 1
 815         default 0 if !PANIC_ON_OOPS
 816         default 1 if PANIC_ON_OOPS
 817
 818 config PANIC_TIMEOUT
 819         int "panic timeout"
 820         default 0
 821         help
 822           Set the timeout value (in seconds) until a reboot occurs when the
 823           the kernel panics. If n = 0, then we wait forever. A timeout
 824           value n > 0 will wait n seconds before rebooting, while a timeout
 825           value n < 0 will reboot immediately.
 826
 827 config LOCKUP_DETECTOR
 828         bool
 829
 830 config SOFTLOCKUP_DETECTOR
 831         bool "Detect Soft Lockups"
 832         depends on DEBUG_KERNEL && !S390
 833         select LOCKUP_DETECTOR
 834         help
 835           Say Y here to enable the kernel to act as a watchdog to detect
 836           soft lockups.
 837
 838           Softlockups are bugs that cause the kernel to loop in kernel
 839           mode for more than 20 seconds, without giving other tasks a
 840           chance to run.  The current stack trace is displayed upon
 841           detection and the system will stay locked up.
 842
 843 config BOOTPARAM_SOFTLOCKUP_PANIC
 844         bool "Panic (Reboot) On Soft Lockups"
 845         depends on SOFTLOCKUP_DETECTOR
 846         help
 847           Say Y here to enable the kernel to panic on "soft lockups",
 848           which are bugs that cause the kernel to loop in kernel
 849           mode for more than 20 seconds (configurable using the watchdog_thresh
 850           sysctl), without giving other tasks a chance to run.
 851
 852           The panic can be used in combination with panic_timeout,
 853           to cause the system to reboot automatically after a
 854           lockup has been detected. This feature is useful for
 855           high-availability systems that have uptime guarantees and
 856           where a lockup must be resolved ASAP.
 857
 858           Say N if unsure.
 859
 860 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
 861         int
 862         depends on SOFTLOCKUP_DETECTOR
 863         range 0 1
 864         default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
 865         default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
 866
 867 config HARDLOCKUP_DETECTOR_PERF
 868         bool
 869         select SOFTLOCKUP_DETECTOR
 870
 871 #
 872 # Enables a timestamp based low pass filter to compensate for perf based
 873 # hard lockup detection which runs too fast due to turbo modes.
 874 #
 875 config HARDLOCKUP_CHECK_TIMESTAMP
 876         bool
 877
 878 #
 879 # arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
 880 # lockup detector rather than the perf based detector.
 881 #
 882 config HARDLOCKUP_DETECTOR
 883         bool "Detect Hard Lockups"
 884         depends on DEBUG_KERNEL && !S390
 885         depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
 886         select LOCKUP_DETECTOR
 887         select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
 888         select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
 889         help
 890           Say Y here to enable the kernel to act as a watchdog to detect
 891           hard lockups.
 892
 893           Hardlockups are bugs that cause the CPU to loop in kernel mode
 894           for more than 10 seconds, without letting other interrupts have a
 895           chance to run.  The current stack trace is displayed upon detection
 896           and the system will stay locked up.
 897
 898 config BOOTPARAM_HARDLOCKUP_PANIC
 899         bool "Panic (Reboot) On Hard Lockups"
 900         depends on HARDLOCKUP_DETECTOR
 901         help
 902           Say Y here to enable the kernel to panic on "hard lockups",
 903           which are bugs that cause the kernel to loop in kernel
 904           mode with interrupts disabled for more than 10 seconds (configurable
 905           using the watchdog_thresh sysctl).
 906
 907           Say N if unsure.
 908
 909 config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
 910         int
 911         depends on HARDLOCKUP_DETECTOR
 912         range 0 1
 913         default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
 914         default 1 if BOOTPARAM_HARDLOCKUP_PANIC
 915
 916 config DETECT_HUNG_TASK
 917         bool "Detect Hung Tasks"
 918         depends on DEBUG_KERNEL
 919         default SOFTLOCKUP_DETECTOR
 920         help
 921           Say Y here to enable the kernel to detect "hung tasks",
 922           which are bugs that cause the task to be stuck in
 923           uninterruptible "D" state indefinitely.
 924
 925           When a hung task is detected, the kernel will print the
 926           current stack trace (which you should report), but the
 927           task will stay in uninterruptible state. If lockdep is
 928           enabled then all held locks will also be reported. This
 929           feature has negligible overhead.
 930
 931 config DEFAULT_HUNG_TASK_TIMEOUT
 932         int "Default timeout for hung task detection (in seconds)"
 933         depends on DETECT_HUNG_TASK
 934         default 120
 935         help
 936           This option controls the default timeout (in seconds) used
 937           to determine when a task has become non-responsive and should
 938           be considered hung.
 939
 940           It can be adjusted at runtime via the kernel.hung_task_timeout_secs
 941           sysctl or by writing a value to
 942           /proc/sys/kernel/hung_task_timeout_secs.
 943
 944           A timeout of 0 disables the check.  The default is two minutes.
 945           Keeping the default should be fine in most cases.
 946
 947 config BOOTPARAM_HUNG_TASK_PANIC
 948         bool "Panic (Reboot) On Hung Tasks"
 949         depends on DETECT_HUNG_TASK
 950         help
 951           Say Y here to enable the kernel to panic on "hung tasks",
 952           which are bugs that cause the kernel to leave a task stuck
 953           in uninterruptible "D" state.
 954
 955           The panic can be used in combination with panic_timeout,
 956           to cause the system to reboot automatically after a
 957           hung task has been detected. This feature is useful for
 958           high-availability systems that have uptime guarantees and
 959           where a hung tasks must be resolved ASAP.
 960
 961           Say N if unsure.
 962
 963 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
 964         int
 965         depends on DETECT_HUNG_TASK
 966         range 0 1
 967         default 0 if !BOOTPARAM_HUNG_TASK_PANIC
 968         default 1 if BOOTPARAM_HUNG_TASK_PANIC
 969
 970 config WQ_WATCHDOG
 971         bool "Detect Workqueue Stalls"
 972         depends on DEBUG_KERNEL
 973         help
 974           Say Y here to enable stall detection on workqueues.  If a
 975           worker pool doesn't make forward progress on a pending work
 976           item for over a given amount of time, 30s by default, a
 977           warning message is printed along with dump of workqueue
 978           state.  This can be configured through kernel parameter
 979           "workqueue.watchdog_thresh" and its sysfs counterpart.
 980
 981 config TEST_LOCKUP
 982         tristate "Test module to generate lockups"
 983         help
 984           This builds the "test_lockup" module that helps to make sure
 985           that watchdogs and lockup detectors are working properly.
 986
 987           Depending on module parameters it could emulate soft or hard
 988           lockup, "hung task", or locking arbitrary lock for a long time.
 989           Also it could generate series of lockups with cooling-down periods.
 990
 991           If unsure, say N.
 992
 993 endmenu # "Debug lockups and hangs"
 994
 995 menu "Scheduler Debugging"
 996
 997 config SCHED_DEBUG
 998         bool "Collect scheduler debugging info"
 999         depends on DEBUG_KERNEL && PROC_FS
1000         default y
1001         help
1002           If you say Y here, the /proc/sched_debug file will be provided
1003           that can help debug the scheduler. The runtime overhead of this
1004           option is minimal.
1005
1006 config SCHED_INFO
1007         bool
1008         default n
1009
1010 config SCHEDSTATS
1011         bool "Collect scheduler statistics"
1012         depends on DEBUG_KERNEL && PROC_FS
1013         select SCHED_INFO
1014         help
1015           If you say Y here, additional code will be inserted into the
1016           scheduler and related routines to collect statistics about
1017           scheduler behavior and provide them in /proc/schedstat.  These
1018           stats may be useful for both tuning and debugging the scheduler
1019           If you aren't debugging the scheduler or trying to tune a specific
1020           application, you can say N to avoid the very slight overhead
1021           this adds.
1022
1023 endmenu
1024
1025 config DEBUG_TIMEKEEPING
1026         bool "Enable extra timekeeping sanity checking"
1027         help
1028           This option will enable additional timekeeping sanity checks
1029           which may be helpful when diagnosing issues where timekeeping
1030           problems are suspected.
1031
1032           This may include checks in the timekeeping hotpaths, so this
1033           option may have a (very small) performance impact to some
1034           workloads.
1035
1036           If unsure, say N.
1037
1038 config DEBUG_PREEMPT
1039         bool "Debug preemptible kernel"
1040         depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1041         default y
1042         help
1043           If you say Y here then the kernel will use a debug variant of the
1044           commonly used smp_processor_id() function and will print warnings
1045           if kernel code uses it in a preemption-unsafe way. Also, the kernel
1046           will detect preemption count underflows.
1047
1048 menu "Lock Debugging (spinlocks, mutexes, etc...)"
1049
1050 config LOCK_DEBUGGING_SUPPORT
1051         bool
1052         depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1053         default y
1054
1055 config PROVE_LOCKING
1056         bool "Lock debugging: prove locking correctness"
1057         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1058         select LOCKDEP
1059         select DEBUG_SPINLOCK
1060         select DEBUG_MUTEXES
1061         select DEBUG_RT_MUTEXES if RT_MUTEXES
1062         select DEBUG_RWSEMS
1063         select DEBUG_WW_MUTEX_SLOWPATH
1064         select DEBUG_LOCK_ALLOC
1065         select TRACE_IRQFLAGS
1066         default n
1067         help
1068          This feature enables the kernel to prove that all locking
1069          that occurs in the kernel runtime is mathematically
1070          correct: that under no circumstance could an arbitrary (and
1071          not yet triggered) combination of observed locking
1072          sequences (on an arbitrary number of CPUs, running an
1073          arbitrary number of tasks and interrupt contexts) cause a
1074          deadlock.
1075
1076          In short, this feature enables the kernel to report locking
1077          related deadlocks before they actually occur.
1078
1079          The proof does not depend on how hard and complex a
1080          deadlock scenario would be to trigger: how many
1081          participant CPUs, tasks and irq-contexts would be needed
1082          for it to trigger. The proof also does not depend on
1083          timing: if a race and a resulting deadlock is possible
1084          theoretically (no matter how unlikely the race scenario
1085          is), it will be proven so and will immediately be
1086          reported by the kernel (once the event is observed that
1087          makes the deadlock theoretically possible).
1088
1089          If a deadlock is impossible (i.e. the locking rules, as
1090          observed by the kernel, are mathematically correct), the
1091          kernel reports nothing.
1092
1093          NOTE: this feature can also be enabled for rwlocks, mutexes
1094          and rwsems - in which case all dependencies between these
1095          different locking variants are observed and mapped too, and
1096          the proof of observed correctness is also maintained for an
1097          arbitrary combination of these separate locking variants.
1098
1099          For more details, see Documentation/locking/lockdep-design.rst.
1100
1101 config PROVE_RAW_LOCK_NESTING
1102         bool "Enable raw_spinlock - spinlock nesting checks"
1103         depends on PROVE_LOCKING
1104         default n
1105         help
1106          Enable the raw_spinlock vs. spinlock nesting checks which ensure
1107          that the lock nesting rules for PREEMPT_RT enabled kernels are
1108          not violated.
1109
1110          NOTE: There are known nesting problems. So if you enable this
1111          option expect lockdep splats until these problems have been fully
1112          addressed which is work in progress. This config switch allows to
1113          identify and analyze these problems. It will be removed and the
1114          check permanentely enabled once the main issues have been fixed.
1115
1116          If unsure, select N.
1117
1118 config LOCK_STAT
1119         bool "Lock usage statistics"
1120         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1121         select LOCKDEP
1122         select DEBUG_SPINLOCK
1123         select DEBUG_MUTEXES
1124         select DEBUG_RT_MUTEXES if RT_MUTEXES
1125         select DEBUG_LOCK_ALLOC
1126         default n
1127         help
1128          This feature enables tracking lock contention points
1129
1130          For more details, see Documentation/locking/lockstat.rst
1131
1132          This also enables lock events required by "perf lock",
1133          subcommand of perf.
1134          If you want to use "perf lock", you also need to turn on
1135          CONFIG_EVENT_TRACING.
1136
1137          CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1138          (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1139
1140 config DEBUG_RT_MUTEXES
1141         bool "RT Mutex debugging, deadlock detection"
1142         depends on DEBUG_KERNEL && RT_MUTEXES
1143         help
1144          This allows rt mutex semantics violations and rt mutex related
1145          deadlocks (lockups) to be detected and reported automatically.
1146
1147 config DEBUG_SPINLOCK
1148         bool "Spinlock and rw-lock debugging: basic checks"
1149         depends on DEBUG_KERNEL
1150         select UNINLINE_SPIN_UNLOCK
1151         help
1152           Say Y here and build SMP to catch missing spinlock initialization
1153           and certain other kinds of spinlock errors commonly made.  This is
1154           best used in conjunction with the NMI watchdog so that spinlock
1155           deadlocks are also debuggable.
1156
1157 config DEBUG_MUTEXES
1158         bool "Mutex debugging: basic checks"
1159         depends on DEBUG_KERNEL
1160         help
1161          This feature allows mutex semantics violations to be detected and
1162          reported.
1163
1164 config DEBUG_WW_MUTEX_SLOWPATH
1165         bool "Wait/wound mutex debugging: Slowpath testing"
1166         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1167         select DEBUG_LOCK_ALLOC
1168         select DEBUG_SPINLOCK
1169         select DEBUG_MUTEXES
1170         help
1171          This feature enables slowpath testing for w/w mutex users by
1172          injecting additional -EDEADLK wound/backoff cases. Together with
1173          the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1174          will test all possible w/w mutex interface abuse with the
1175          exception of simply not acquiring all the required locks.
1176          Note that this feature can introduce significant overhead, so
1177          it really should not be enabled in a production or distro kernel,
1178          even a debug kernel.  If you are a driver writer, enable it.  If
1179          you are a distro, do not.
1180
1181 config DEBUG_RWSEMS
1182         bool "RW Semaphore debugging: basic checks"
1183         depends on DEBUG_KERNEL
1184         help
1185           This debugging feature allows mismatched rw semaphore locks
1186           and unlocks to be detected and reported.
1187
1188 config DEBUG_LOCK_ALLOC
1189         bool "Lock debugging: detect incorrect freeing of live locks"
1190         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1191         select DEBUG_SPINLOCK
1192         select DEBUG_MUTEXES
1193         select DEBUG_RT_MUTEXES if RT_MUTEXES
1194         select LOCKDEP
1195         help
1196          This feature will check whether any held lock (spinlock, rwlock,
1197          mutex or rwsem) is incorrectly freed by the kernel, via any of the
1198          memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1199          vfree(), etc.), whether a live lock is incorrectly reinitialized via
1200          spin_lock_init()/mutex_init()/etc., or whether there is any lock
1201          held during task exit.
1202
1203 config LOCKDEP
1204         bool
1205         depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1206         select STACKTRACE
1207         select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
1208         select KALLSYMS
1209         select KALLSYMS_ALL
1210
1211 config LOCKDEP_SMALL
1212         bool
1213
1214 config DEBUG_LOCKDEP
1215         bool "Lock dependency engine debugging"
1216         depends on DEBUG_KERNEL && LOCKDEP
1217         help
1218           If you say Y here, the lock dependency engine will do
1219           additional runtime checks to debug itself, at the price
1220           of more runtime overhead.
1221
1222 config DEBUG_ATOMIC_SLEEP
1223         bool "Sleep inside atomic section checking"
1224         select PREEMPT_COUNT
1225         depends on DEBUG_KERNEL
1226         depends on !ARCH_NO_PREEMPT
1227         help
1228           If you say Y here, various routines which may sleep will become very
1229           noisy if they are called inside atomic sections: when a spinlock is
1230           held, inside an rcu read side critical section, inside preempt disabled
1231           sections, inside an interrupt, etc...
1232
1233 config DEBUG_LOCKING_API_SELFTESTS
1234         bool "Locking API boot-time self-tests"
1235         depends on DEBUG_KERNEL
1236         help
1237           Say Y here if you want the kernel to run a short self-test during
1238           bootup. The self-test checks whether common types of locking bugs
1239           are detected by debugging mechanisms or not. (if you disable
1240           lock debugging then those bugs wont be detected of course.)
1241           The following locking APIs are covered: spinlocks, rwlocks,
1242           mutexes and rwsems.
1243
1244 config LOCK_TORTURE_TEST
1245         tristate "torture tests for locking"
1246         depends on DEBUG_KERNEL
1247         select TORTURE_TEST
1248         help
1249           This option provides a kernel module that runs torture tests
1250           on kernel locking primitives.  The kernel module may be built
1251           after the fact on the running kernel to be tested, if desired.
1252
1253           Say Y here if you want kernel locking-primitive torture tests
1254           to be built into the kernel.
1255           Say M if you want these torture tests to build as a module.
1256           Say N if you are unsure.
1257
1258 config WW_MUTEX_SELFTEST
1259         tristate "Wait/wound mutex selftests"
1260         help
1261           This option provides a kernel module that runs tests on the
1262           on the struct ww_mutex locking API.
1263
1264           It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1265           with this test harness.
1266
1267           Say M if you want these self tests to build as a module.
1268           Say N if you are unsure.
1269
1270 endmenu # lock debugging
1271
1272 config TRACE_IRQFLAGS
1273         bool
1274         help
1275           Enables hooks to interrupt enabling and disabling for
1276           either tracing or lock debugging.
1277
1278 config STACKTRACE
1279         bool "Stack backtrace support"
1280         depends on STACKTRACE_SUPPORT
1281         help
1282           This option causes the kernel to create a /proc/pid/stack for
1283           every process, showing its current stack trace.
1284           It is also used by various kernel debugging features that require
1285           stack trace generation.
1286
1287 config WARN_ALL_UNSEEDED_RANDOM
1288         bool "Warn for all uses of unseeded randomness"
1289         default n
1290         help
1291           Some parts of the kernel contain bugs relating to their use of
1292           cryptographically secure random numbers before it's actually possible
1293           to generate those numbers securely. This setting ensures that these
1294           flaws don't go unnoticed, by enabling a message, should this ever
1295           occur. This will allow people with obscure setups to know when things
1296           are going wrong, so that they might contact developers about fixing
1297           it.
1298
1299           Unfortunately, on some models of some architectures getting
1300           a fully seeded CRNG is extremely difficult, and so this can
1301           result in dmesg getting spammed for a surprisingly long
1302           time.  This is really bad from a security perspective, and
1303           so architecture maintainers really need to do what they can
1304           to get the CRNG seeded sooner after the system is booted.
1305           However, since users cannot do anything actionable to
1306           address this, by default the kernel will issue only a single
1307           warning for the first use of unseeded randomness.
1308
1309           Say Y here if you want to receive warnings for all uses of
1310           unseeded randomness.  This will be of use primarily for
1311           those developers interested in improving the security of
1312           Linux kernels running on their architecture (or
1313           subarchitecture).
1314
1315 config DEBUG_KOBJECT
1316         bool "kobject debugging"
1317         depends on DEBUG_KERNEL
1318         help
1319           If you say Y here, some extra kobject debugging messages will be sent
1320           to the syslog.
1321
1322 config DEBUG_KOBJECT_RELEASE
1323         bool "kobject release debugging"
1324         depends on DEBUG_OBJECTS_TIMERS
1325         help
1326           kobjects are reference counted objects.  This means that their
1327           last reference count put is not predictable, and the kobject can
1328           live on past the point at which a driver decides to drop it's
1329           initial reference to the kobject gained on allocation.  An
1330           example of this would be a struct device which has just been
1331           unregistered.
1332
1333           However, some buggy drivers assume that after such an operation,
1334           the memory backing the kobject can be immediately freed.  This
1335           goes completely against the principles of a refcounted object.
1336
1337           If you say Y here, the kernel will delay the release of kobjects
1338           on the last reference count to improve the visibility of this
1339           kind of kobject release bug.
1340
1341 config HAVE_DEBUG_BUGVERBOSE
1342         bool
1343
1344 menu "Debug kernel data structures"
1345
1346 config DEBUG_LIST
1347         bool "Debug linked list manipulation"
1348         depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
1349         help
1350           Enable this to turn on extended checks in the linked-list
1351           walking routines.
1352
1353           If unsure, say N.
1354
1355 config DEBUG_PLIST
1356         bool "Debug priority linked list manipulation"
1357         depends on DEBUG_KERNEL
1358         help
1359           Enable this to turn on extended checks in the priority-ordered
1360           linked-list (plist) walking routines.  This checks the entire
1361           list multiple times during each manipulation.
1362
1363           If unsure, say N.
1364
1365 config DEBUG_SG
1366         bool "Debug SG table operations"
1367         depends on DEBUG_KERNEL
1368         help
1369           Enable this to turn on checks on scatter-gather tables. This can
1370           help find problems with drivers that do not properly initialize
1371           their sg tables.
1372
1373           If unsure, say N.
1374
1375 config DEBUG_NOTIFIERS
1376         bool "Debug notifier call chains"
1377         depends on DEBUG_KERNEL
1378         help
1379           Enable this to turn on sanity checking for notifier call chains.
1380           This is most useful for kernel developers to make sure that
1381           modules properly unregister themselves from notifier chains.
1382           This is a relatively cheap check but if you care about maximum
1383           performance, say N.
1384
1385 config BUG_ON_DATA_CORRUPTION
1386         bool "Trigger a BUG when data corruption is detected"
1387         select DEBUG_LIST
1388         help
1389           Select this option if the kernel should BUG when it encounters
1390           data corruption in kernel memory structures when they get checked
1391           for validity.
1392
1393           If unsure, say N.
1394
1395 endmenu
1396
1397 config DEBUG_CREDENTIALS
1398         bool "Debug credential management"
1399         depends on DEBUG_KERNEL
1400         help
1401           Enable this to turn on some debug checking for credential
1402           management.  The additional code keeps track of the number of
1403           pointers from task_structs to any given cred struct, and checks to
1404           see that this number never exceeds the usage count of the cred
1405           struct.
1406
1407           Furthermore, if SELinux is enabled, this also checks that the
1408           security pointer in the cred struct is never seen to be invalid.
1409
1410           If unsure, say N.
1411
1412 source "kernel/rcu/Kconfig.debug"
1413
1414 config DEBUG_WQ_FORCE_RR_CPU
1415         bool "Force round-robin CPU selection for unbound work items"
1416         depends on DEBUG_KERNEL
1417         default n
1418         help
1419           Workqueue used to implicitly guarantee that work items queued
1420           without explicit CPU specified are put on the local CPU.  This
1421           guarantee is no longer true and while local CPU is still
1422           preferred work items may be put on foreign CPUs.  Kernel
1423           parameter "workqueue.debug_force_rr_cpu" is added to force
1424           round-robin CPU selection to flush out usages which depend on the
1425           now broken guarantee.  This config option enables the debug
1426           feature by default.  When enabled, memory and cache locality will
1427           be impacted.
1428
1429 config DEBUG_BLOCK_EXT_DEVT
1430         bool "Force extended block device numbers and spread them"
1431         depends on DEBUG_KERNEL
1432         depends on BLOCK
1433         default n
1434         help
1435           BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1436           SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1437           YOU ARE DOING.  Distros, please enable this and fix whatever
1438           is broken.
1439
1440           Conventionally, block device numbers are allocated from
1441           predetermined contiguous area.  However, extended block area
1442           may introduce non-contiguous block device numbers.  This
1443           option forces most block device numbers to be allocated from
1444           the extended space and spreads them to discover kernel or
1445           userland code paths which assume predetermined contiguous
1446           device number allocation.
1447
1448           Note that turning on this debug option shuffles all the
1449           device numbers for all IDE and SCSI devices including libata
1450           ones, so root partition specified using device number
1451           directly (via rdev or root=MAJ:MIN) won't work anymore.
1452           Textual device names (root=/dev/sdXn) will continue to work.
1453
1454           Say N if you are unsure.
1455
1456 config CPU_HOTPLUG_STATE_CONTROL
1457         bool "Enable CPU hotplug state control"
1458         depends on DEBUG_KERNEL
1459         depends on HOTPLUG_CPU
1460         default n
1461         help
1462           Allows to write steps between "offline" and "online" to the CPUs
1463           sysfs target file so states can be stepped granular. This is a debug
1464           option for now as the hotplug machinery cannot be stopped and
1465           restarted at arbitrary points yet.
1466
1467           Say N if your are unsure.
1468
1469 config LATENCYTOP
1470         bool "Latency measuring infrastructure"
1471         depends on DEBUG_KERNEL
1472         depends on STACKTRACE_SUPPORT
1473         depends on PROC_FS
1474         select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1475         select KALLSYMS
1476         select KALLSYMS_ALL
1477         select STACKTRACE
1478         select SCHEDSTATS
1479         select SCHED_DEBUG
1480         help
1481           Enable this option if you want to use the LatencyTOP tool
1482           to find out which userspace is blocking on what kernel operations.
1483
1484 source "kernel/trace/Kconfig"
1485
1486 config PROVIDE_OHCI1394_DMA_INIT
1487         bool "Remote debugging over FireWire early on boot"
1488         depends on PCI && X86
1489         help
1490           If you want to debug problems which hang or crash the kernel early
1491           on boot and the crashing machine has a FireWire port, you can use
1492           this feature to remotely access the memory of the crashed machine
1493           over FireWire. This employs remote DMA as part of the OHCI1394
1494           specification which is now the standard for FireWire controllers.
1495
1496           With remote DMA, you can monitor the printk buffer remotely using
1497           firescope and access all memory below 4GB using fireproxy from gdb.
1498           Even controlling a kernel debugger is possible using remote DMA.
1499
1500           Usage:
1501
1502           If ohci1394_dma=early is used as boot parameter, it will initialize
1503           all OHCI1394 controllers which are found in the PCI config space.
1504
1505           As all changes to the FireWire bus such as enabling and disabling
1506           devices cause a bus reset and thereby disable remote DMA for all
1507           devices, be sure to have the cable plugged and FireWire enabled on
1508           the debugging host before booting the debug target for debugging.
1509
1510           This code (~1k) is freed after boot. By then, the firewire stack
1511           in charge of the OHCI-1394 controllers should be used instead.
1512
1513           See Documentation/debugging-via-ohci1394.txt for more information.
1514
1515 source "samples/Kconfig"
1516
1517 config ARCH_HAS_DEVMEM_IS_ALLOWED
1518         bool
1519
1520 config STRICT_DEVMEM
1521         bool "Filter access to /dev/mem"
1522         depends on MMU && DEVMEM
1523         depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1524         default y if PPC || X86 || ARM64
1525         help
1526           If this option is disabled, you allow userspace (root) access to all
1527           of memory, including kernel and userspace memory. Accidental
1528           access to this is obviously disastrous, but specific access can
1529           be used by people debugging the kernel. Note that with PAT support
1530           enabled, even in this case there are restrictions on /dev/mem
1531           use due to the cache aliasing requirements.
1532
1533           If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1534           file only allows userspace access to PCI space and the BIOS code and
1535           data regions.  This is sufficient for dosemu and X and all common
1536           users of /dev/mem.
1537
1538           If in doubt, say Y.
1539
1540 config IO_STRICT_DEVMEM
1541         bool "Filter I/O access to /dev/mem"
1542         depends on STRICT_DEVMEM
1543         help
1544           If this option is disabled, you allow userspace (root) access to all
1545           io-memory regardless of whether a driver is actively using that
1546           range.  Accidental access to this is obviously disastrous, but
1547           specific access can be used by people debugging kernel drivers.
1548
1549           If this option is switched on, the /dev/mem file only allows
1550           userspace access to *idle* io-memory ranges (see /proc/iomem) This
1551           may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1552           if the driver using a given range cannot be disabled.
1553
1554           If in doubt, say Y.
1555
1556 menu "$(SRCARCH) Debugging"
1557
1558 source "arch/$(SRCARCH)/Kconfig.debug"
1559
1560 endmenu
1561
1562 menu "Kernel Testing and Coverage"
1563
1564 source "lib/kunit/Kconfig"
1565
1566 config NOTIFIER_ERROR_INJECTION
1567         tristate "Notifier error injection"
1568         depends on DEBUG_KERNEL
1569         select DEBUG_FS
1570         help
1571           This option provides the ability to inject artificial errors to
1572           specified notifier chain callbacks. It is useful to test the error
1573           handling of notifier call chain failures.
1574
1575           Say N if unsure.
1576
1577 config PM_NOTIFIER_ERROR_INJECT
1578         tristate "PM notifier error injection module"
1579         depends on PM && NOTIFIER_ERROR_INJECTION
1580         default m if PM_DEBUG
1581         help
1582           This option provides the ability to inject artificial errors to
1583           PM notifier chain callbacks.  It is controlled through debugfs
1584           interface /sys/kernel/debug/notifier-error-inject/pm
1585
1586           If the notifier call chain should be failed with some events
1587           notified, write the error code to "actions/<notifier event>/error".
1588
1589           Example: Inject PM suspend error (-12 = -ENOMEM)
1590
1591           # cd /sys/kernel/debug/notifier-error-inject/pm/
1592           # echo -12 > actions/PM_SUSPEND_PREPARE/error
1593           # echo mem > /sys/power/state
1594           bash: echo: write error: Cannot allocate memory
1595
1596           To compile this code as a module, choose M here: the module will
1597           be called pm-notifier-error-inject.
1598
1599           If unsure, say N.
1600
1601 config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1602         tristate "OF reconfig notifier error injection module"
1603         depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
1604         help
1605           This option provides the ability to inject artificial errors to
1606           OF reconfig notifier chain callbacks.  It is controlled
1607           through debugfs interface under
1608           /sys/kernel/debug/notifier-error-inject/OF-reconfig/
1609
1610           If the notifier call chain should be failed with some events
1611           notified, write the error code to "actions/<notifier event>/error".
1612
1613           To compile this code as a module, choose M here: the module will
1614           be called of-reconfig-notifier-error-inject.
1615
1616           If unsure, say N.
1617
1618 config NETDEV_NOTIFIER_ERROR_INJECT
1619         tristate "Netdev notifier error injection module"
1620         depends on NET && NOTIFIER_ERROR_INJECTION
1621         help
1622           This option provides the ability to inject artificial errors to
1623           netdevice notifier chain callbacks.  It is controlled through debugfs
1624           interface /sys/kernel/debug/notifier-error-inject/netdev
1625
1626           If the notifier call chain should be failed with some events
1627           notified, write the error code to "actions/<notifier event>/error".
1628
1629           Example: Inject netdevice mtu change error (-22 = -EINVAL)
1630
1631           # cd /sys/kernel/debug/notifier-error-inject/netdev
1632           # echo -22 > actions/NETDEV_CHANGEMTU/error
1633           # ip link set eth0 mtu 1024
1634           RTNETLINK answers: Invalid argument
1635
1636           To compile this code as a module, choose M here: the module will
1637           be called netdev-notifier-error-inject.
1638
1639           If unsure, say N.
1640
1641 config FUNCTION_ERROR_INJECTION
1642         def_bool y
1643         depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1644
1645 config FAULT_INJECTION
1646         bool "Fault-injection framework"
1647         depends on DEBUG_KERNEL
1648         help
1649           Provide fault-injection framework.
1650           For more details, see Documentation/fault-injection/.
1651
1652 config FAILSLAB
1653         bool "Fault-injection capability for kmalloc"
1654         depends on FAULT_INJECTION
1655         depends on SLAB || SLUB
1656         help
1657           Provide fault-injection capability for kmalloc.
1658
1659 config FAIL_PAGE_ALLOC
1660         bool "Fault-injection capability for alloc_pages()"
1661         depends on FAULT_INJECTION
1662         help
1663           Provide fault-injection capability for alloc_pages().
1664
1665 config FAIL_MAKE_REQUEST
1666         bool "Fault-injection capability for disk IO"
1667         depends on FAULT_INJECTION && BLOCK
1668         help
1669           Provide fault-injection capability for disk IO.
1670
1671 config FAIL_IO_TIMEOUT
1672         bool "Fault-injection capability for faking disk interrupts"
1673         depends on FAULT_INJECTION && BLOCK
1674         help
1675           Provide fault-injection capability on end IO handling. This
1676           will make the block layer "forget" an interrupt as configured,
1677           thus exercising the error handling.
1678
1679           Only works with drivers that use the generic timeout handling,
1680           for others it wont do anything.
1681
1682 config FAIL_FUTEX
1683         bool "Fault-injection capability for futexes"
1684         select DEBUG_FS
1685         depends on FAULT_INJECTION && FUTEX
1686         help
1687           Provide fault-injection capability for futexes.
1688
1689 config FAULT_INJECTION_DEBUG_FS
1690         bool "Debugfs entries for fault-injection capabilities"
1691         depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1692         help
1693           Enable configuration of fault-injection capabilities via debugfs.
1694
1695 config FAIL_FUNCTION
1696         bool "Fault-injection capability for functions"
1697         depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1698         help
1699           Provide function-based fault-injection capability.
1700           This will allow you to override a specific function with a return
1701           with given return value. As a result, function caller will see
1702           an error value and have to handle it. This is useful to test the
1703           error handling in various subsystems.
1704
1705 config FAIL_MMC_REQUEST
1706         bool "Fault-injection capability for MMC IO"
1707         depends on FAULT_INJECTION_DEBUG_FS && MMC
1708         help
1709           Provide fault-injection capability for MMC IO.
1710           This will make the mmc core return data errors. This is
1711           useful to test the error handling in the mmc block device
1712           and to test how the mmc host driver handles retries from
1713           the block device.
1714
1715 config FAULT_INJECTION_STACKTRACE_FILTER
1716         bool "stacktrace filter for fault-injection capabilities"
1717         depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
1718         depends on !X86_64
1719         select STACKTRACE
1720         select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1721         help
1722           Provide stacktrace filter for fault-injection capabilities
1723
1724 config ARCH_HAS_KCOV
1725         bool
1726         help
1727           An architecture should select this when it can successfully
1728           build and run with CONFIG_KCOV. This typically requires
1729           disabling instrumentation for some early boot code.
1730
1731 config CC_HAS_SANCOV_TRACE_PC
1732         def_bool $(cc-option,-fsanitize-coverage=trace-pc)
1733
1734
1735 config KCOV
1736         bool "Code coverage for fuzzing"
1737         depends on ARCH_HAS_KCOV
1738         depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1739         select DEBUG_FS
1740         select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1741         help
1742           KCOV exposes kernel code coverage information in a form suitable
1743           for coverage-guided fuzzing (randomized testing).
1744
1745           If RANDOMIZE_BASE is enabled, PC values will not be stable across
1746           different machines and across reboots. If you need stable PC values,
1747           disable RANDOMIZE_BASE.
1748
1749           For more details, see Documentation/dev-tools/kcov.rst.
1750
1751 config KCOV_ENABLE_COMPARISONS
1752         bool "Enable comparison operands collection by KCOV"
1753         depends on KCOV
1754         depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1755         help
1756           KCOV also exposes operands of every comparison in the instrumented
1757           code along with operand sizes and PCs of the comparison instructions.
1758           These operands can be used by fuzzing engines to improve the quality
1759           of fuzzing coverage.
1760
1761 config KCOV_INSTRUMENT_ALL
1762         bool "Instrument all code by default"
1763         depends on KCOV
1764         default y
1765         help
1766           If you are doing generic system call fuzzing (like e.g. syzkaller),
1767           then you will want to instrument the whole kernel and you should
1768           say y here. If you are doing more targeted fuzzing (like e.g.
1769           filesystem fuzzing with AFL) then you will want to enable coverage
1770           for more specific subsets of files, and should say n here.
1771
1772 menuconfig RUNTIME_TESTING_MENU
1773         bool "Runtime Testing"
1774         def_bool y
1775
1776 if RUNTIME_TESTING_MENU
1777
1778 config LKDTM
1779         tristate "Linux Kernel Dump Test Tool Module"
1780         depends on DEBUG_FS
1781         help
1782         This module enables testing of the different dumping mechanisms by
1783         inducing system failures at predefined crash points.
1784         If you don't need it: say N
1785         Choose M here to compile this code as a module. The module will be
1786         called lkdtm.
1787
1788         Documentation on how to use the module can be found in
1789         Documentation/fault-injection/provoke-crashes.rst
1790
1791 config TEST_LIST_SORT
1792         tristate "Linked list sorting test"
1793         depends on DEBUG_KERNEL || m
1794         help
1795           Enable this to turn on 'list_sort()' function test. This test is
1796           executed only once during system boot (so affects only boot time),
1797           or at module load time.
1798
1799           If unsure, say N.
1800
1801 config TEST_MIN_HEAP
1802         tristate "Min heap test"
1803         depends on DEBUG_KERNEL || m
1804         help
1805           Enable this to turn on min heap function tests. This test is
1806           executed only once during system boot (so affects only boot time),
1807           or at module load time.
1808
1809           If unsure, say N.
1810
1811 config TEST_SORT
1812         tristate "Array-based sort test"
1813         depends on DEBUG_KERNEL || m
1814         help
1815           This option enables the self-test function of 'sort()' at boot,
1816           or at module load time.
1817
1818           If unsure, say N.
1819
1820 config KPROBES_SANITY_TEST
1821         bool "Kprobes sanity tests"
1822         depends on DEBUG_KERNEL
1823         depends on KPROBES
1824         help
1825           This option provides for testing basic kprobes functionality on
1826           boot. Samples of kprobe and kretprobe are inserted and
1827           verified for functionality.
1828
1829           Say N if you are unsure.
1830
1831 config BACKTRACE_SELF_TEST
1832         tristate "Self test for the backtrace code"
1833         depends on DEBUG_KERNEL
1834         help
1835           This option provides a kernel module that can be used to test
1836           the kernel stack backtrace code. This option is not useful
1837           for distributions or general kernels, but only for kernel
1838           developers working on architecture code.
1839
1840           Note that if you want to also test saved backtraces, you will
1841           have to enable STACKTRACE as well.
1842
1843           Say N if you are unsure.
1844
1845 config RBTREE_TEST
1846         tristate "Red-Black tree test"
1847         depends on DEBUG_KERNEL
1848         help
1849           A benchmark measuring the performance of the rbtree library.
1850           Also includes rbtree invariant checks.
1851
1852 config REED_SOLOMON_TEST
1853         tristate "Reed-Solomon library test"
1854         depends on DEBUG_KERNEL || m
1855         select REED_SOLOMON
1856         select REED_SOLOMON_ENC16
1857         select REED_SOLOMON_DEC16
1858         help
1859           This option enables the self-test function of rslib at boot,
1860           or at module load time.
1861
1862           If unsure, say N.
1863
1864 config INTERVAL_TREE_TEST
1865         tristate "Interval tree test"
1866         depends on DEBUG_KERNEL
1867         select INTERVAL_TREE
1868         help
1869           A benchmark measuring the performance of the interval tree library
1870
1871 config PERCPU_TEST
1872         tristate "Per cpu operations test"
1873         depends on m && DEBUG_KERNEL
1874         help
1875           Enable this option to build test module which validates per-cpu
1876           operations.
1877
1878           If unsure, say N.
1879
1880 config ATOMIC64_SELFTEST
1881         tristate "Perform an atomic64_t self-test"
1882         help
1883           Enable this option to test the atomic64_t functions at boot or
1884           at module load time.
1885
1886           If unsure, say N.
1887
1888 config ASYNC_RAID6_TEST
1889         tristate "Self test for hardware accelerated raid6 recovery"
1890         depends on ASYNC_RAID6_RECOV
1891         select ASYNC_MEMCPY
1892         ---help---
1893           This is a one-shot self test that permutes through the
1894           recovery of all the possible two disk failure scenarios for a
1895           N-disk array.  Recovery is performed with the asynchronous
1896           raid6 recovery routines, and will optionally use an offload
1897           engine if one is available.
1898
1899           If unsure, say N.
1900
1901 config TEST_HEXDUMP
1902         tristate "Test functions located in the hexdump module at runtime"
1903
1904 config TEST_STRING_HELPERS
1905         tristate "Test functions located in the string_helpers module at runtime"
1906
1907 config TEST_STRSCPY
1908         tristate "Test strscpy*() family of functions at runtime"
1909
1910 config TEST_KSTRTOX
1911         tristate "Test kstrto*() family of functions at runtime"
1912
1913 config TEST_PRINTF
1914         tristate "Test printf() family of functions at runtime"
1915
1916 config TEST_BITMAP
1917         tristate "Test bitmap_*() family of functions at runtime"
1918         help
1919           Enable this option to test the bitmap functions at boot.
1920
1921           If unsure, say N.
1922
1923 config TEST_BITFIELD
1924         tristate "Test bitfield functions at runtime"
1925         help
1926           Enable this option to test the bitfield functions at boot.
1927
1928           If unsure, say N.
1929
1930 config TEST_UUID
1931         tristate "Test functions located in the uuid module at runtime"
1932
1933 config TEST_XARRAY
1934         tristate "Test the XArray code at runtime"
1935
1936 config TEST_OVERFLOW
1937         tristate "Test check_*_overflow() functions at runtime"
1938
1939 config TEST_RHASHTABLE
1940         tristate "Perform selftest on resizable hash table"
1941         help
1942           Enable this option to test the rhashtable functions at boot.
1943
1944           If unsure, say N.
1945
1946 config TEST_HASH
1947         tristate "Perform selftest on hash functions"
1948         help
1949           Enable this option to test the kernel's integer (<linux/hash.h>),
1950           string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1951           hash functions on boot (or module load).
1952
1953           This is intended to help people writing architecture-specific
1954           optimized versions.  If unsure, say N.
1955
1956 config TEST_IDA
1957         tristate "Perform selftest on IDA functions"
1958
1959 config TEST_PARMAN
1960         tristate "Perform selftest on priority array manager"
1961         depends on PARMAN
1962         help
1963           Enable this option to test priority array manager on boot
1964           (or module load).
1965
1966           If unsure, say N.
1967
1968 config TEST_IRQ_TIMINGS
1969         bool "IRQ timings selftest"
1970         depends on IRQ_TIMINGS
1971         help
1972           Enable this option to test the irq timings code on boot.
1973
1974           If unsure, say N.
1975
1976 config TEST_LKM
1977         tristate "Test module loading with 'hello world' module"
1978         depends on m
1979         help
1980           This builds the "test_module" module that emits "Hello, world"
1981           on printk when loaded. It is designed to be used for basic
1982           evaluation of the module loading subsystem (for example when
1983           validating module verification). It lacks any extra dependencies,
1984           and will not normally be loaded by the system unless explicitly
1985           requested by name.
1986
1987           If unsure, say N.
1988
1989 config TEST_VMALLOC
1990         tristate "Test module for stress/performance analysis of vmalloc allocator"
1991         default n
1992        depends on MMU
1993         depends on m
1994         help
1995           This builds the "test_vmalloc" module that should be used for
1996           stress and performance analysis. So, any new change for vmalloc
1997           subsystem can be evaluated from performance and stability point
1998           of view.
1999
2000           If unsure, say N.
2001
2002 config TEST_USER_COPY
2003         tristate "Test user/kernel boundary protections"
2004         depends on m
2005         help
2006           This builds the "test_user_copy" module that runs sanity checks
2007           on the copy_to/from_user infrastructure, making sure basic
2008           user/kernel boundary testing is working. If it fails to load,
2009           a regression has been detected in the user/kernel memory boundary
2010           protections.
2011
2012           If unsure, say N.
2013
2014 config TEST_BPF
2015         tristate "Test BPF filter functionality"
2016         depends on m && NET
2017         help
2018           This builds the "test_bpf" module that runs various test vectors
2019           against the BPF interpreter or BPF JIT compiler depending on the
2020           current setting. This is in particular useful for BPF JIT compiler
2021           development, but also to run regression tests against changes in
2022           the interpreter code. It also enables test stubs for eBPF maps and
2023           verifier used by user space verifier testsuite.
2024
2025           If unsure, say N.
2026
2027 config TEST_BLACKHOLE_DEV
2028         tristate "Test blackhole netdev functionality"
2029         depends on m && NET
2030         help
2031           This builds the "test_blackhole_dev" module that validates the
2032           data path through this blackhole netdev.
2033
2034           If unsure, say N.
2035
2036 config FIND_BIT_BENCHMARK
2037         tristate "Test find_bit functions"
2038         help
2039           This builds the "test_find_bit" module that measure find_*_bit()
2040           functions performance.
2041
2042           If unsure, say N.
2043
2044 config TEST_FIRMWARE
2045         tristate "Test firmware loading via userspace interface"
2046         depends on FW_LOADER
2047         help
2048           This builds the "test_firmware" module that creates a userspace
2049           interface for testing firmware loading. This can be used to
2050           control the triggering of firmware loading without needing an
2051           actual firmware-using device. The contents can be rechecked by
2052           userspace.
2053
2054           If unsure, say N.
2055
2056 config TEST_SYSCTL
2057         tristate "sysctl test driver"
2058         depends on PROC_SYSCTL
2059         help
2060           This builds the "test_sysctl" module. This driver enables to test the
2061           proc sysctl interfaces available to drivers safely without affecting
2062           production knobs which might alter system functionality.
2063
2064           If unsure, say N.
2065
2066 config SYSCTL_KUNIT_TEST
2067         tristate "KUnit test for sysctl"
2068         depends on KUNIT
2069         help
2070           This builds the proc sysctl unit test, which runs on boot.
2071           Tests the API contract and implementation correctness of sysctl.
2072           For more information on KUnit and unit tests in general please refer
2073           to the KUnit documentation in Documentation/dev-tools/kunit/.
2074
2075           If unsure, say N.
2076
2077 config LIST_KUNIT_TEST
2078         tristate "KUnit Test for Kernel Linked-list structures"
2079         depends on KUNIT
2080         help
2081           This builds the linked list KUnit test suite.
2082           It tests that the API and basic functionality of the list_head type
2083           and associated macros.
2084
2085           KUnit tests run during boot and output the results to the debug log
2086           in TAP format (http://testanything.org/). Only useful for kernel devs
2087           running the KUnit test harness, and not intended for inclusion into a
2088           production build.
2089
2090           For more information on KUnit and unit tests in general please refer
2091           to the KUnit documentation in Documentation/dev-tools/kunit/.
2092
2093           If unsure, say N.
2094
2095 config TEST_UDELAY
2096         tristate "udelay test driver"
2097         help
2098           This builds the "udelay_test" module that helps to make sure
2099           that udelay() is working properly.
2100
2101           If unsure, say N.
2102
2103 config TEST_STATIC_KEYS
2104         tristate "Test static keys"
2105         depends on m
2106         help
2107           Test the static key interfaces.
2108
2109           If unsure, say N.
2110
2111 config TEST_KMOD
2112         tristate "kmod stress tester"
2113         depends on m
2114         depends on NETDEVICES && NET_CORE && INET # for TUN
2115         depends on BLOCK
2116         select TEST_LKM
2117         select XFS_FS
2118         select TUN
2119         select BTRFS_FS
2120         help
2121           Test the kernel's module loading mechanism: kmod. kmod implements
2122           support to load modules using the Linux kernel's usermode helper.
2123           This test provides a series of tests against kmod.
2124
2125           Although technically you can either build test_kmod as a module or
2126           into the kernel we disallow building it into the kernel since
2127           it stress tests request_module() and this will very likely cause
2128           some issues by taking over precious threads available from other
2129           module load requests, ultimately this could be fatal.
2130
2131           To run tests run:
2132
2133           tools/testing/selftests/kmod/kmod.sh --help
2134
2135           If unsure, say N.
2136
2137 config TEST_DEBUG_VIRTUAL
2138         tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2139         depends on DEBUG_VIRTUAL
2140         help
2141           Test the kernel's ability to detect incorrect calls to
2142           virt_to_phys() done against the non-linear part of the
2143           kernel's virtual address map.
2144
2145           If unsure, say N.
2146
2147 config TEST_MEMCAT_P
2148         tristate "Test memcat_p() helper function"
2149         help
2150           Test the memcat_p() helper for correctly merging two
2151           pointer arrays together.
2152
2153           If unsure, say N.
2154
2155 config TEST_LIVEPATCH
2156         tristate "Test livepatching"
2157         default n
2158         depends on DYNAMIC_DEBUG
2159         depends on LIVEPATCH
2160         depends on m
2161         help
2162           Test kernel livepatching features for correctness.  The tests will
2163           load test modules that will be livepatched in various scenarios.
2164
2165           To run all the livepatching tests:
2166
2167           make -C tools/testing/selftests TARGETS=livepatch run_tests
2168
2169           Alternatively, individual tests may be invoked:
2170
2171           tools/testing/selftests/livepatch/test-callbacks.sh
2172           tools/testing/selftests/livepatch/test-livepatch.sh
2173           tools/testing/selftests/livepatch/test-shadow-vars.sh
2174
2175           If unsure, say N.
2176
2177 config TEST_OBJAGG
2178         tristate "Perform selftest on object aggreration manager"
2179         default n
2180         depends on OBJAGG
2181         help
2182           Enable this option to test object aggregation manager on boot
2183           (or module load).
2184
2185
2186 config TEST_STACKINIT
2187         tristate "Test level of stack variable initialization"
2188         help
2189           Test if the kernel is zero-initializing stack variables and
2190           padding. Coverage is controlled by compiler flags,
2191           CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2192           or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2193
2194           If unsure, say N.
2195
2196 config TEST_MEMINIT
2197         tristate "Test heap/page initialization"
2198         help
2199           Test if the kernel is zero-initializing heap and page allocations.
2200           This can be useful to test init_on_alloc and init_on_free features.
2201
2202           If unsure, say N.
2203
2204 endif # RUNTIME_TESTING_MENU
2205
2206 config MEMTEST
2207         bool "Memtest"
2208         ---help---
2209           This option adds a kernel parameter 'memtest', which allows memtest
2210           to be set.
2211                 memtest=0, mean disabled; -- default
2212                 memtest=1, mean do 1 test pattern;
2213                 ...
2214                 memtest=17, mean do 17 test patterns.
2215           If you are unsure how to answer this question, answer N.
2216
2217
2218
2219 config HYPERV_TESTING
2220         bool "Microsoft Hyper-V driver testing"
2221         default n
2222         depends on HYPERV && DEBUG_FS
2223         help
2224           Select this option to enable Hyper-V vmbus testing.
2225
2226 endmenu # "Kernel Testing and Coverage"
2227
2228 endmenu # Kernel hacking