Kconfig.debug 37.4 KB
Newer Older
L
Linus Torvalds 已提交
1 2 3

config PRINTK_TIME
	bool "Show timing information on printks"
4
	depends on PRINTK
L
Linus Torvalds 已提交
5 6 7 8 9 10 11
	help
	  Selecting this option causes timing information to be
	  included in printk output.  This allows you to measure
	  the interval between kernel operations, including bootup
	  operations.  This is useful for identifying long delays
	  in kernel startup.

12 13 14 15 16 17 18 19
config ENABLE_WARN_DEPRECATED
	bool "Enable __deprecated logic"
	default y
	help
	  Enable the __deprecated logic in the kernel build.
	  Disable this to suppress the "warning: 'foo' is deprecated
	  (declared at kernel/power/somefile.c:1234)" messages.

A
Andrew Morton 已提交
20 21 22 23 24 25 26
config ENABLE_MUST_CHECK
	bool "Enable __must_check logic"
	default y
	help
	  Enable the __must_check logic in the kernel build.  Disable this to
	  suppress the "warning: ignoring return value of 'foo', declared with
	  attribute warn_unused_result" messages.
L
Linus Torvalds 已提交
27

28 29 30 31 32 33 34 35 36 37 38
config FRAME_WARN
	int "Warn for stack frames larger than (needs gcc 4.4)"
	range 0 8192
	default 1024 if !64BIT
	default 2048 if 64BIT
	help
	  Tell gcc to warn at build time for stack frames larger than this.
	  Setting this too low will cause a lot of warnings.
	  Setting it to 0 disables the warning.
	  Requires gcc 4.4

L
Linus Torvalds 已提交
39 40
config MAGIC_SYSRQ
	bool "Magic SysRq key"
41
	depends on !UML
L
Linus Torvalds 已提交
42 43 44 45 46 47 48 49 50 51 52
	help
	  If you say Y here, you will have some control over the system even
	  if the system crashes for example during kernel debugging (e.g., you
	  will be able to flush the buffer cache to disk, reboot the system
	  immediately or dump some status information). This is accomplished
	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
	  also works on a serial console (on PC hardware at least), if you
	  send a BREAK and then within 5 seconds a command keypress. The
	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
	  unless you really know what this hack does.

53 54 55 56 57 58 59 60
config STRIP_ASM_SYMS
	bool "Strip assembler-generated symbols during link"
	default n
	help
	  Strip internal assembler-generated symbols during a link (symbols
	  that look like '.Lxxx') so they don't pollute the output of
	  get_wchan() and suchlike.

61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
config UNUSED_SYMBOLS
	bool "Enable unused/obsolete exported symbols"
	default y if X86
	help
	  Unused but exported symbols make the kernel needlessly bigger.  For
	  that reason most of these unused exports will soon be removed.  This
	  option is provided temporarily to provide a transition period in case
	  some external kernel module needs one of these symbols anyway. If you
	  encounter such a case in your module, consider if you are actually
	  using the right API.  (rationale: since nobody in the kernel is using
	  this in a module, there is a pretty good chance it's actually the
	  wrong interface to use).  If you really need the symbol, please send a
	  mail to the linux kernel mailing list mentioning the symbol and why
	  you really need it, and what the merge plan to the mainline kernel for
	  your module is.

77 78 79 80 81 82 83 84
config DEBUG_FS
	bool "Debug Filesystem"
	depends on SYSFS
	help
	  debugfs is a virtual file system that kernel developers use to put
	  debugging files into.  Enable this option to be able to read and
	  write to these files.

85 86 87
	  For detailed documentation on the debugfs API, see
	  Documentation/DocBook/filesystems.

88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103
	  If unsure, say N.

config HEADERS_CHECK
	bool "Run 'make headers_check' when building vmlinux"
	depends on !UML
	help
	  This option will extract the user-visible kernel headers whenever
	  building the kernel, and will run basic sanity checks on them to
	  ensure that exported files do not attempt to include files which
	  were not exported, etc.

	  If you're making modifications to header files which are
	  relevant for userspace, say 'Y', and check the headers
	  exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
	  your build tree), to make sure they're suitable.

104 105
config DEBUG_SECTION_MISMATCH
	bool "Enable full Section mismatch analysis"
106
	depends on UNDEFINED
107
	# This option is on purpose disabled for now.
108
	# It will be enabled when we are down to a reasonable number
109
	# of section mismatch warnings (< 10 for an allyesconfig build)
110 111 112 113 114 115 116 117
	help
	  The section mismatch analysis checks if there are illegal
	  references from one section to another section.
	  Linux will during link or during runtime drop some sections
	  and any use of code/data previously in these sections will
	  most likely result in an oops.
	  In the code functions and variables are annotated with
	  __init, __devinit etc. (see full list in include/linux/init.h)
118 119 120
	  which results in the code/data being placed in specific sections.
	  The section mismatch analysis is always done after a full
	  kernel build but enabling this option will in addition
121 122 123
	  do the following:
	  - Add the option -fno-inline-functions-called-once to gcc
	    When inlining a function annotated __init in a non-init
124
	    function we would lose the section information and thus
125
	    the analysis would not catch the illegal reference.
126
	    This option tells gcc to inline less but will also
127 128 129
	    result in a larger kernel.
	  - Run the section mismatch analysis for each module/built-in.o
	    When we run the section mismatch analysis on vmlinux.o we
130
	    lose valueble information about where the mismatch was
131 132 133 134 135
	    introduced.
	    Running the analysis for each module/built-in.o file
	    will tell where the mismatch happens much closer to the
	    source. The drawback is that we will report the same
	    mismatch at least twice.
136 137
	  - Enable verbose reporting from modpost to help solving
	    the section mismatches reported.
138

139 140 141 142 143 144
config DEBUG_KERNEL
	bool "Kernel debugging"
	help
	  Say Y here if you are developing drivers or trying to debug and
	  identify kernel problems.

D
David Woodhouse 已提交
145 146 147 148 149 150 151 152 153
config DEBUG_SHIRQ
	bool "Debug shared IRQ handlers"
	depends on DEBUG_KERNEL && GENERIC_HARDIRQS
	help
	  Enable this to generate a spurious interrupt as soon as a shared
	  interrupt handler is registered, and just before one is deregistered.
	  Drivers ought to be able to handle interrupts coming in at those
	  points; some don't and need to be caught.

I
Ingo Molnar 已提交
154 155
config DETECT_SOFTLOCKUP
	bool "Detect Soft Lockups"
156
	depends on DEBUG_KERNEL && !S390
I
Ingo Molnar 已提交
157 158 159 160
	default y
	help
	  Say Y here to enable the kernel to detect "soft lockups",
	  which are bugs that cause the kernel to loop in kernel
I
Ingo Molnar 已提交
161
	  mode for more than 60 seconds, without giving other tasks a
I
Ingo Molnar 已提交
162 163 164 165 166 167 168 169 170 171 172
	  chance to run.

	  When a soft-lockup is detected, the kernel will print the
	  current stack trace (which you should report), but the
	  system will stay locked up. This feature has negligible
	  overhead.

	  (Note that "hard lockups" are separate type of bugs that
	   can be detected via the NMI-watchdog, on platforms that
	   support it.)

I
Ingo Molnar 已提交
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196
config BOOTPARAM_SOFTLOCKUP_PANIC
	bool "Panic (Reboot) On Soft Lockups"
	depends on DETECT_SOFTLOCKUP
	help
	  Say Y here to enable the kernel to panic on "soft lockups",
	  which are bugs that cause the kernel to loop in kernel
	  mode for more than 60 seconds, without giving other tasks a
	  chance to run.

	  The panic can be used in combination with panic_timeout,
	  to cause the system to reboot automatically after a
	  lockup has been detected. This feature is useful for
	  high-availability systems that have uptime guarantees and
	  where a lockup must be resolved ASAP.

	  Say N if unsure.

config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
	int
	depends on DETECT_SOFTLOCKUP
	range 0 1
	default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
	default 1 if BOOTPARAM_SOFTLOCKUP_PANIC

197 198 199
config DETECT_HUNG_TASK
	bool "Detect Hung Tasks"
	depends on DEBUG_KERNEL
200
	default DETECT_SOFTLOCKUP
201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234
	help
	  Say Y here to enable the kernel to detect "hung tasks",
	  which are bugs that cause the task to be stuck in
	  uninterruptible "D" state indefinitiley.

	  When a hung task is detected, the kernel will print the
	  current stack trace (which you should report), but the
	  task will stay in uninterruptible state. If lockdep is
	  enabled then all held locks will also be reported. This
	  feature has negligible overhead.

config BOOTPARAM_HUNG_TASK_PANIC
	bool "Panic (Reboot) On Hung Tasks"
	depends on DETECT_HUNG_TASK
	help
	  Say Y here to enable the kernel to panic on "hung tasks",
	  which are bugs that cause the kernel to leave a task stuck
	  in uninterruptible "D" state.

	  The panic can be used in combination with panic_timeout,
	  to cause the system to reboot automatically after a
	  hung task has been detected. This feature is useful for
	  high-availability systems that have uptime guarantees and
	  where a hung tasks must be resolved ASAP.

	  Say N if unsure.

config BOOTPARAM_HUNG_TASK_PANIC_VALUE
	int
	depends on DETECT_HUNG_TASK
	range 0 1
	default 0 if !BOOTPARAM_HUNG_TASK_PANIC
	default 1 if BOOTPARAM_HUNG_TASK_PANIC

235 236 237 238 239 240 241 242 243
config SCHED_DEBUG
	bool "Collect scheduler debugging info"
	depends on DEBUG_KERNEL && PROC_FS
	default y
	help
	  If you say Y here, the /proc/sched_debug file will be provided
	  that can help debug the scheduler. The runtime overhead of this
	  option is minimal.

L
Linus Torvalds 已提交
244 245 246 247 248 249 250 251 252 253 254 255
config SCHEDSTATS
	bool "Collect scheduler statistics"
	depends on DEBUG_KERNEL && PROC_FS
	help
	  If you say Y here, additional code will be inserted into the
	  scheduler and related routines to collect statistics about
	  scheduler behavior and provide them in /proc/schedstat.  These
	  stats may be useful for both tuning and debugging the scheduler
	  If you aren't debugging the scheduler or trying to tune a specific
	  application, you can say N to avoid the very slight overhead
	  this adds.

256 257 258 259 260 261 262 263 264
config TIMER_STATS
	bool "Collect kernel timers statistics"
	depends on DEBUG_KERNEL && PROC_FS
	help
	  If you say Y here, additional code will be inserted into the
	  timer routines to collect statistics about kernel timers being
	  reprogrammed. The statistics can be read from /proc/timer_stats.
	  The statistics collection is started by writing 1 to /proc/timer_stats,
	  writing 0 stops it. This feature is useful to collect information
I
Ingo Molnar 已提交
265 266 267 268
	  about timer usage patterns in kernel and userspace. This feature
	  is lightweight if enabled in the kernel config but not activated
	  (it defaults to deactivated on bootup and will only be activated
	  if some application like powertop activates it explicitly).
269

270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292
config DEBUG_OBJECTS
	bool "Debug object operations"
	depends on DEBUG_KERNEL
	help
	  If you say Y here, additional code will be inserted into the
	  kernel to track the life time of various objects and validate
	  the operations on those objects.

config DEBUG_OBJECTS_SELFTEST
	bool "Debug objects selftest"
	depends on DEBUG_OBJECTS
	help
	  This enables the selftest of the object debug code.

config DEBUG_OBJECTS_FREE
	bool "Debug objects in freed memory"
	depends on DEBUG_OBJECTS
	help
	  This enables checks whether a k/v free operation frees an area
	  which contains an object which has not been deactivated
	  properly. This can make kmalloc/kfree-intensive workloads
	  much slower.

293 294 295 296 297 298 299 300
config DEBUG_OBJECTS_TIMERS
	bool "Debug timer objects"
	depends on DEBUG_OBJECTS
	help
	  If you say Y here, additional code will be inserted into the
	  timer routines to track the life time of timer objects and
	  validate the timer operations.

301 302 303 304 305 306 307 308
config DEBUG_OBJECTS_WORK
	bool "Debug work objects"
	depends on DEBUG_OBJECTS
	help
	  If you say Y here, additional code will be inserted into the
	  work queue routines to track the life time of work objects and
	  validate the work operations.

309 310 311 312 313 314 315 316
config DEBUG_OBJECTS_ENABLE_DEFAULT
	int "debug_objects bootup default value (0-1)"
        range 0 1
        default "1"
        depends on DEBUG_OBJECTS
        help
          Debug objects boot parameter default value

L
Linus Torvalds 已提交
317
config DEBUG_SLAB
318
	bool "Debug slab memory allocations"
319
	depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
L
Linus Torvalds 已提交
320 321 322 323 324
	help
	  Say Y here to have the kernel do limited verification on memory
	  allocation as well as poisoning memory on free to catch use of freed
	  memory. This can make kmalloc/kfree-intensive workloads much slower.

325 326 327 328
config DEBUG_SLAB_LEAK
	bool "Memory leak debugging"
	depends on DEBUG_SLAB

329 330
config SLUB_DEBUG_ON
	bool "SLUB debugging on by default"
331
	depends on SLUB && SLUB_DEBUG && !KMEMCHECK
332 333 334 335 336 337 338 339 340 341
	default n
	help
	  Boot with debugging on by default. SLUB boots by default with
	  the runtime debug capabilities switched off. Enabling this is
	  equivalent to specifying the "slub_debug" parameter on boot.
	  There is no support for more fine grained debug control like
	  possible with slub_debug=xxx. SLUB debugging may be switched
	  off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
	  "slub_debug=-".

342 343 344
config SLUB_STATS
	default n
	bool "Enable SLUB performance statistics"
345
	depends on SLUB && SLUB_DEBUG && SYSFS
346 347 348 349 350 351 352 353 354
	help
	  SLUB statistics are useful to debug SLUBs allocation behavior in
	  order find ways to optimize the allocator. This should never be
	  enabled for production use since keeping statistics slows down
	  the allocator by a few percentage points. The slabinfo command
	  supports the determination of the most active slabs to figure
	  out which slabs are relevant to a particular load.
	  Try running: slabinfo -DA

355 356
config DEBUG_KMEMLEAK
	bool "Kernel memory leak detector"
H
Heiko Carstens 已提交
357
	depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
C
Chris Smith 已提交
358
		(X86 || ARM || PPC || S390 || SUPERH)
H
Heiko Carstens 已提交
359

360 361 362
	select DEBUG_FS if SYSFS
	select STACKTRACE if STACKTRACE_SUPPORT
	select KALLSYMS
363
	select CRC32
364 365 366 367 368 369 370 371 372 373
	help
	  Say Y here if you want to enable the memory leak
	  detector. The memory allocation/freeing is traced in a way
	  similar to the Boehm's conservative garbage collector, the
	  difference being that the orphan objects are not freed but
	  only shown in /sys/kernel/debug/kmemleak. Enabling this
	  feature will introduce an overhead to memory
	  allocations. See Documentation/kmemleak.txt for more
	  details.

374 375 376
	  Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
	  of finding leaks due to the slab objects poisoning.

377 378 379
	  In order to access the kmemleak file, debugfs needs to be
	  mounted (usually at /sys/kernel/debug).

380 381 382
config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
	int "Maximum kmemleak early log entries"
	depends on DEBUG_KMEMLEAK
H
Heiko Carstens 已提交
383
	range 200 40000
384 385 386 387 388 389 390 391
	default 400
	help
	  Kmemleak must track all the memory allocations to avoid
	  reporting false positives. Since memory may be allocated or
	  freed before kmemleak is initialised, an early log buffer is
	  used to store these actions. If kmemleak reports "early log
	  buffer exceeded", please increase this value.

392 393 394 395 396 397 398 399 400 401
config DEBUG_KMEMLEAK_TEST
	tristate "Simple test for the kernel memory leak detector"
	depends on DEBUG_KMEMLEAK
	help
	  Say Y or M here to build a test for the kernel memory leak
	  detector. This option enables a module that explicitly leaks
	  memory.

	  If unsure, say N.

L
Linus Torvalds 已提交
402 403
config DEBUG_PREEMPT
	bool "Debug preemptible kernel"
404
	depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
L
Linus Torvalds 已提交
405 406 407 408 409 410 411
	default y
	help
	  If you say Y here then the kernel will use a debug variant of the
	  commonly used smp_processor_id() function and will print warnings
	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
	  will detect preemption count underflows.

I
Ingo Molnar 已提交
412 413 414 415 416 417 418 419 420 421 422 423
config DEBUG_RT_MUTEXES
	bool "RT Mutex debugging, deadlock detection"
	depends on DEBUG_KERNEL && RT_MUTEXES
	help
	 This allows rt mutex semantics violations and rt mutex related
	 deadlocks (lockups) to be detected and reported automatically.

config DEBUG_PI_LIST
	bool
	default y
	depends on DEBUG_RT_MUTEXES

424 425
config RT_MUTEX_TESTER
	bool "Built-in scriptable tester for rt-mutexes"
426
	depends on DEBUG_KERNEL && RT_MUTEXES
427 428 429
	help
	  This option enables a rt-mutex tester.

L
Linus Torvalds 已提交
430
config DEBUG_SPINLOCK
I
Ingo Molnar 已提交
431
	bool "Spinlock and rw-lock debugging: basic checks"
L
Linus Torvalds 已提交
432 433 434 435 436 437 438
	depends on DEBUG_KERNEL
	help
	  Say Y here and build SMP to catch missing spinlock initialization
	  and certain other kinds of spinlock errors commonly made.  This is
	  best used in conjunction with the NMI watchdog so that spinlock
	  deadlocks are also debuggable.

I
Ingo Molnar 已提交
439 440 441 442 443 444 445 446 447
config DEBUG_MUTEXES
	bool "Mutex debugging: basic checks"
	depends on DEBUG_KERNEL
	help
	 This feature allows mutex semantics violations to be detected and
	 reported.

config DEBUG_LOCK_ALLOC
	bool "Lock debugging: detect incorrect freeing of live locks"
448
	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
I
Ingo Molnar 已提交
449 450 451 452 453 454 455 456 457 458 459 460 461
	select DEBUG_SPINLOCK
	select DEBUG_MUTEXES
	select LOCKDEP
	help
	 This feature will check whether any held lock (spinlock, rwlock,
	 mutex or rwsem) is incorrectly freed by the kernel, via any of the
	 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
	 vfree(), etc.), whether a live lock is incorrectly reinitialized via
	 spin_lock_init()/mutex_init()/etc., or whether there is any lock
	 held during task exit.

config PROVE_LOCKING
	bool "Lock debugging: prove locking correctness"
462
	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
I
Ingo Molnar 已提交
463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501
	select LOCKDEP
	select DEBUG_SPINLOCK
	select DEBUG_MUTEXES
	select DEBUG_LOCK_ALLOC
	default n
	help
	 This feature enables the kernel to prove that all locking
	 that occurs in the kernel runtime is mathematically
	 correct: that under no circumstance could an arbitrary (and
	 not yet triggered) combination of observed locking
	 sequences (on an arbitrary number of CPUs, running an
	 arbitrary number of tasks and interrupt contexts) cause a
	 deadlock.

	 In short, this feature enables the kernel to report locking
	 related deadlocks before they actually occur.

	 The proof does not depend on how hard and complex a
	 deadlock scenario would be to trigger: how many
	 participant CPUs, tasks and irq-contexts would be needed
	 for it to trigger. The proof also does not depend on
	 timing: if a race and a resulting deadlock is possible
	 theoretically (no matter how unlikely the race scenario
	 is), it will be proven so and will immediately be
	 reported by the kernel (once the event is observed that
	 makes the deadlock theoretically possible).

	 If a deadlock is impossible (i.e. the locking rules, as
	 observed by the kernel, are mathematically correct), the
	 kernel reports nothing.

	 NOTE: this feature can also be enabled for rwlocks, mutexes
	 and rwsems - in which case all dependencies between these
	 different locking variants are observed and mapped too, and
	 the proof of observed correctness is also maintained for an
	 arbitrary combination of these separate locking variants.

	 For more details, see Documentation/lockdep-design.txt.

502 503 504 505 506 507 508 509 510 511 512 513
config PROVE_RCU
	bool "RCU debugging: prove RCU correctness"
	depends on PROVE_LOCKING
	default n
	help
	 This feature enables lockdep extensions that check for correct
	 use of RCU APIs.  This is currently under development.  Say Y
	 if you want to debug RCU usage or help work on the PROVE_RCU
	 feature.

	 Say N if you are unsure.

I
Ingo Molnar 已提交
514 515
config LOCKDEP
	bool
516
	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
I
Ingo Molnar 已提交
517
	select STACKTRACE
518
	select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
I
Ingo Molnar 已提交
519 520 521
	select KALLSYMS
	select KALLSYMS_ALL

P
Peter Zijlstra 已提交
522
config LOCK_STAT
D
Danny ter Haar 已提交
523
	bool "Lock usage statistics"
P
Peter Zijlstra 已提交
524 525 526 527 528 529 530 531 532
	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
	select LOCKDEP
	select DEBUG_SPINLOCK
	select DEBUG_MUTEXES
	select DEBUG_LOCK_ALLOC
	default n
	help
	 This feature enables tracking lock contention points

P
Peter Zijlstra 已提交
533 534
	 For more details, see Documentation/lockstat.txt

535 536 537 538
	 This also enables lock events required by "perf lock",
	 subcommand of perf.
	 If you want to use "perf lock", you also need to turn on
	 CONFIG_EVENT_TRACING.
539 540

	 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
541
	 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
542

I
Ingo Molnar 已提交
543 544
config DEBUG_LOCKDEP
	bool "Lock dependency engine debugging"
545
	depends on DEBUG_KERNEL && LOCKDEP
I
Ingo Molnar 已提交
546 547 548 549 550 551
	help
	  If you say Y here, the lock dependency engine will do
	  additional runtime checks to debug itself, at the price
	  of more runtime overhead.

config TRACE_IRQFLAGS
552
	depends on DEBUG_KERNEL
I
Ingo Molnar 已提交
553 554 555 556 557
	bool
	default y
	depends on TRACE_IRQFLAGS_SUPPORT
	depends on PROVE_LOCKING

L
Linus Torvalds 已提交
558
config DEBUG_SPINLOCK_SLEEP
I
Ingo Molnar 已提交
559
	bool "Spinlock debugging: sleep-inside-spinlock checking"
L
Linus Torvalds 已提交
560 561 562 563 564
	depends on DEBUG_KERNEL
	help
	  If you say Y here, various routines which may sleep will become very
	  noisy if they are called with a spinlock held.

565 566 567 568 569 570 571 572 573 574 575
config DEBUG_LOCKING_API_SELFTESTS
	bool "Locking API boot-time self-tests"
	depends on DEBUG_KERNEL
	help
	  Say Y here if you want the kernel to run a short self-test during
	  bootup. The self-test checks whether common types of locking bugs
	  are detected by debugging mechanisms or not. (if you disable
	  lock debugging then those bugs wont be detected of course.)
	  The following locking APIs are covered: spinlocks, rwlocks,
	  mutexes and rwsems.

576 577 578 579
config STACKTRACE
	bool
	depends on STACKTRACE_SUPPORT

L
Linus Torvalds 已提交
580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595
config DEBUG_KOBJECT
	bool "kobject debugging"
	depends on DEBUG_KERNEL
	help
	  If you say Y here, some extra kobject debugging messages will be sent
	  to the syslog. 

config DEBUG_HIGHMEM
	bool "Highmem debugging"
	depends on DEBUG_KERNEL && HIGHMEM
	help
	  This options enables addition error checking for high memory systems.
	  Disable for production systems.

config DEBUG_BUGVERBOSE
	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
M
Matt Mackall 已提交
596
	depends on BUG
597 598
	depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
		   FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
599
	default y
L
Linus Torvalds 已提交
600 601 602 603 604 605 606 607 608 609 610
	help
	  Say Y here to make BUG() panics output the file name and line number
	  of the BUG call as well as the EIP and oops trace.  This aids
	  debugging but costs about 70-100K of memory.

config DEBUG_INFO
	bool "Compile the kernel with debug info"
	depends on DEBUG_KERNEL
	help
          If you say Y here the resulting kernel image will include
	  debugging info resulting in a larger kernel image.
611 612 613
	  This adds debug symbols to the kernel and modules (gcc -g), and
	  is needed if you intend to use kernel crashdump or binary object
	  tools like crash, kgdb, LKCD, gdb, etc on the kernel.
L
Linus Torvalds 已提交
614 615 616 617
	  Say Y here only if you plan to debug the kernel.

	  If unsure, say N.

618 619 620 621
config DEBUG_VM
	bool "Debug VM"
	depends on DEBUG_KERNEL
	help
N
Nick Piggin 已提交
622 623
	  Enable this to turn on extended checks in the virtual-memory system
          that may impact performance.
624 625 626

	  If unsure, say N.

J
Jiri Slaby 已提交
627 628 629 630 631 632 633 634 635
config DEBUG_VIRTUAL
	bool "Debug VM translations"
	depends on DEBUG_KERNEL && X86
	help
	  Enable some costly sanity checks in virtual to page code. This can
	  catch mistakes with virt_to_page() and friends.

	  If unsure, say N.

636 637 638 639 640 641 642
config DEBUG_NOMMU_REGIONS
	bool "Debug the global anon/private NOMMU mapping region tree"
	depends on DEBUG_KERNEL && !MMU
	help
	  This option causes the global tree of anonymous and private mapping
	  regions to be regularly checked for invalid topology.

643 644 645 646 647 648 649 650 651 652
config DEBUG_WRITECOUNT
	bool "Debug filesystem writers count"
	depends on DEBUG_KERNEL
	help
	  Enable this to catch wrong use of the writers count in struct
	  vfsmount.  This will increase the size of each file struct by
	  32 bits.

	  If unsure, say N.

653 654 655 656 657 658 659 660 661 662 663 664
config DEBUG_MEMORY_INIT
	bool "Debug memory initialisation" if EMBEDDED
	default !EMBEDDED
	help
	  Enable this for additional checks during memory initialisation.
	  The sanity checks verify aspects of the VM such as the memory model
	  and other information provided by the architecture. Verbose
	  information will be printed at KERN_DEBUG loglevel depending
	  on the mminit_loglevel= command-line option.

	  If unsure, say Y

665 666 667 668 669 670 671 672 673
config DEBUG_LIST
	bool "Debug linked list manipulation"
	depends on DEBUG_KERNEL
	help
	  Enable this to turn on extended checks in the linked-list
	  walking routines.

	  If unsure, say N.

J
Jens Axboe 已提交
674 675 676 677 678 679 680 681 682 683
config DEBUG_SG
	bool "Debug SG table operations"
	depends on DEBUG_KERNEL
	help
	  Enable this to turn on checks on scatter-gather tables. This can
	  help find problems with drivers that do not properly initialize
	  their sg tables.

	  If unsure, say N.

684 685 686 687 688 689 690 691 692 693
config DEBUG_NOTIFIERS
	bool "Debug notifier call chains"
	depends on DEBUG_KERNEL
	help
	  Enable this to turn on sanity checking for notifier call chains.
	  This is most useful for kernel developers to make sure that
	  modules properly unregister themselves from notifier chains.
	  This is a relatively cheap check but if you care about maximum
	  performance, say N.

694 695 696 697 698 699 700 701 702 703 704 705 706 707 708
config DEBUG_CREDENTIALS
	bool "Debug credential management"
	depends on DEBUG_KERNEL
	help
	  Enable this to turn on some debug checking for credential
	  management.  The additional code keeps track of the number of
	  pointers from task_structs to any given cred struct, and checks to
	  see that this number never exceeds the usage count of the cred
	  struct.

	  Furthermore, if SELinux is enabled, this also checks that the
	  security pointer in the cred struct is never seen to be invalid.

	  If unsure, say N.

709 710 711 712 713 714 715 716 717
#
# Select this config option from the architecture Kconfig, if it
# it is preferred to always offer frame pointers as a config
# option on the architecture (regardless of KERNEL_DEBUG):
#
config ARCH_WANT_FRAME_POINTERS
	bool
	help

L
Linus Torvalds 已提交
718 719
config FRAME_POINTER
	bool "Compile the kernel with frame pointers"
720
	depends on DEBUG_KERNEL && \
721
		(CRIS || M68K || M68KNOMMU || FRV || UML || \
722 723 724 725 726 727 728
		 AVR32 || SUPERH || BLACKFIN || MN10300) || \
		ARCH_WANT_FRAME_POINTERS
	default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
	help
	  If you say Y here the resulting kernel image will be slightly
	  larger and slower, but it gives very useful debugging information
	  in case of kernel bugs. (precise oopses/stacktraces/warnings)
L
Linus Torvalds 已提交
729

R
Randy Dunlap 已提交
730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747
config BOOT_PRINTK_DELAY
	bool "Delay each boot printk message by N milliseconds"
	depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
	help
	  This build option allows you to read kernel boot messages
	  by inserting a short delay after each one.  The delay is
	  specified in milliseconds on the kernel command line,
	  using "boot_delay=N".

	  It is likely that you would also need to use "lpj=M" to preset
	  the "loops per jiffie" value.
	  See a previous boot log for the "lpj" value to use for your
	  system, and then set "lpj=M" before setting "boot_delay=N".
	  NOTE:  Using this option may adversely affect SMP systems.
	  I.e., processors other than the first one may not boot up.
	  BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
	  what it believes to be lockup conditions.

748 749 750 751 752 753 754 755 756
config RCU_TORTURE_TEST
	tristate "torture tests for RCU"
	depends on DEBUG_KERNEL
	default n
	help
	  This option provides a kernel module that runs torture tests
	  on the RCU infrastructure.  The kernel module may be built
	  after the fact on the running kernel to be tested, if desired.

757 758
	  Say Y here if you want RCU torture tests to be built into
	  the kernel.
759 760
	  Say M if you want the RCU torture tests to build as a module.
	  Say N if you are unsure.
761

762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778
config RCU_TORTURE_TEST_RUNNABLE
	bool "torture tests for RCU runnable by default"
	depends on RCU_TORTURE_TEST = y
	default n
	help
	  This option provides a way to build the RCU torture tests
	  directly into the kernel without them starting up at boot
	  time.  You can use /proc/sys/kernel/rcutorture_runnable
	  to manually override this setting.  This /proc file is
	  available only when the RCU torture tests have been built
	  into the kernel.

	  Say Y here if you want the RCU torture tests to start during
	  boot (you probably don't).
	  Say N here if you want the RCU torture tests to start only
	  after being manually enabled via /proc.

779 780
config RCU_CPU_STALL_DETECTOR
	bool "Check for stalled CPUs delaying RCU grace periods"
781
	depends on TREE_RCU || TREE_PREEMPT_RCU
782
	default y
783 784 785 786
	help
	  This option causes RCU to printk information on which
	  CPUs are delaying the current grace period, but only when
	  the grace period extends for excessive time periods.
787

788
	  Say N if you want to disable such checks.
789

790
	  Say Y if you are unsure.
791

792 793 794 795 796 797 798
config RCU_CPU_STALL_VERBOSE
	bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
	depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
	default n
	help
	  This option causes RCU to printk detailed per-task information
	  for any tasks that are stalling the current RCU grace period.
799 800 801

	  Say N if you are unsure.

802 803
	  Say Y if you want to enable such checks.

804 805 806 807 808 809 810 811 812 813 814 815
config KPROBES_SANITY_TEST
	bool "Kprobes sanity tests"
	depends on DEBUG_KERNEL
	depends on KPROBES
	default n
	help
	  This option provides for testing basic kprobes functionality on
	  boot. A sample kprobe, jprobe and kretprobe are inserted and
	  verified for functionality.

	  Say N if you are unsure.

816 817 818 819 820 821 822 823 824 825
config BACKTRACE_SELF_TEST
	tristate "Self test for the backtrace code"
	depends on DEBUG_KERNEL
	default n
	help
	  This option provides a kernel module that can be used to test
	  the kernel stack backtrace code. This option is not useful
	  for distributions or general kernels, but only for kernel
	  developers working on architecture code.

826 827 828
	  Note that if you want to also test saved backtraces, you will
	  have to enable STACKTRACE as well.

829 830
	  Say N if you are unsure.

831 832 833 834
config DEBUG_BLOCK_EXT_DEVT
        bool "Force extended block device numbers and spread them"
	depends on DEBUG_KERNEL
	depends on BLOCK
835
	default n
836
	help
837 838 839 840 841
	  BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
	  SOME DISTRIBUTIONS.  DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
	  YOU ARE DOING.  Distros, please enable this and fix whatever
	  is broken.

842 843 844 845 846 847 848 849
	  Conventionally, block device numbers are allocated from
	  predetermined contiguous area.  However, extended block area
	  may introduce non-contiguous block device numbers.  This
	  option forces most block device numbers to be allocated from
	  the extended space and spreads them to discover kernel or
	  userland code paths which assume predetermined contiguous
	  device number allocation.

850 851 852 853 854 855
	  Note that turning on this debug option shuffles all the
	  device numbers for all IDE and SCSI devices including libata
	  ones, so root partition specified using device number
	  directly (via rdev or root=MAJ:MIN) won't work anymore.
	  Textual device names (root=/dev/sdXn) will continue to work.

856 857
	  Say N if you are unsure.

858 859 860 861 862 863 864 865 866 867 868 869 870 871 872
config DEBUG_FORCE_WEAK_PER_CPU
	bool "Force weak per-cpu definitions"
	depends on DEBUG_KERNEL
	help
	  s390 and alpha require percpu variables in modules to be
	  defined weak to work around addressing range issue which
	  puts the following two restrictions on percpu variable
	  definitions.

	  1. percpu symbols must be unique whether static or not
	  2. percpu variables can't be defined inside a function

	  To ensure that generic code follows the above rules, this
	  option forces all percpu variables to be defined as weak.

873 874
config LKDTM
	tristate "Linux Kernel Dump Test Tool Module"
875
	depends on DEBUG_FS
C
Chris Snook 已提交
876
	depends on BLOCK
877 878 879 880 881 882 883 884 885
	default n
	help
	This module enables testing of the different dumping mechanisms by
	inducing system failures at predefined crash points.
	If you don't need it: say N
	Choose M here to compile this code as a module. The module will be
	called lkdtm.

	Documentation on how to use the module can be found in
886
	Documentation/fault-injection/provoke-crashes.txt
887 888

config FAULT_INJECTION
889 890
	bool "Fault-injection framework"
	depends on DEBUG_KERNEL
891 892 893
	help
	  Provide fault-injection framework.
	  For more details, see Documentation/fault-injection/.
894

895
config FAILSLAB
896 897
	bool "Fault-injection capability for kmalloc"
	depends on FAULT_INJECTION
A
Akinobu Mita 已提交
898
	depends on SLAB || SLUB
899
	help
900
	  Provide fault-injection capability for kmalloc.
901

902 903
config FAIL_PAGE_ALLOC
	bool "Fault-injection capabilitiy for alloc_pages()"
904
	depends on FAULT_INJECTION
905
	help
906
	  Provide fault-injection capability for alloc_pages().
907

908
config FAIL_MAKE_REQUEST
D
Dave Jones 已提交
909
	bool "Fault-injection capability for disk IO"
910
	depends on FAULT_INJECTION && BLOCK
911
	help
912
	  Provide fault-injection capability for disk IO.
913

914 915 916 917 918 919 920 921 922 923 924
config FAIL_IO_TIMEOUT
	bool "Faul-injection capability for faking disk interrupts"
	depends on FAULT_INJECTION && BLOCK
	help
	  Provide fault-injection capability on end IO handling. This
	  will make the block layer "forget" an interrupt as configured,
	  thus exercising the error handling.

	  Only works with drivers that use the generic timeout handling,
	  for others it wont do anything.

925 926
config FAULT_INJECTION_DEBUG_FS
	bool "Debugfs entries for fault-injection capabilities"
927
	depends on FAULT_INJECTION && SYSFS && DEBUG_FS
928
	help
929
	  Enable configuration of fault-injection capabilities via debugfs.
930 931 932 933

config FAULT_INJECTION_STACKTRACE_FILTER
	bool "stacktrace filter for fault-injection capabilities"
	depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
934
	depends on !X86_64
935
	select STACKTRACE
936
	select FRAME_POINTER if !PPC && !S390
937 938
	help
	  Provide stacktrace filter for fault-injection capabilities
M
Mathieu Desnoyers 已提交
939

A
Arjan van de Ven 已提交
940 941
config LATENCYTOP
	bool "Latency measuring infrastructure"
942
	select FRAME_POINTER if !MIPS && !PPC && !S390
A
Arjan van de Ven 已提交
943 944 945 946 947
	select KALLSYMS
	select KALLSYMS_ALL
	select STACKTRACE
	select SCHEDSTATS
	select SCHED_DEBUG
948
	depends on HAVE_LATENCYTOP_SUPPORT
A
Arjan van de Ven 已提交
949 950 951 952
	help
	  Enable this option if you want to use the LatencyTOP tool
	  to find out which userspace is blocking on what kernel operations.

953 954
config SYSCTL_SYSCALL_CHECK
	bool "Sysctl checks"
955
	depends on SYSCTL
956 957 958 959 960
	---help---
	  sys_sysctl uses binary paths that have been found challenging
	  to properly maintain and use. This enables checks that help
	  you to keep things correct.

A
Akinobu Mita 已提交
961
source mm/Kconfig.debug
962 963
source kernel/trace/Kconfig

964
config PROVIDE_OHCI1394_DMA_INIT
965
	bool "Remote debugging over FireWire early on boot"
966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991
	depends on PCI && X86
	help
	  If you want to debug problems which hang or crash the kernel early
	  on boot and the crashing machine has a FireWire port, you can use
	  this feature to remotely access the memory of the crashed machine
	  over FireWire. This employs remote DMA as part of the OHCI1394
	  specification which is now the standard for FireWire controllers.

	  With remote DMA, you can monitor the printk buffer remotely using
	  firescope and access all memory below 4GB using fireproxy from gdb.
	  Even controlling a kernel debugger is possible using remote DMA.

	  Usage:

	  If ohci1394_dma=early is used as boot parameter, it will initialize
	  all OHCI1394 controllers which are found in the PCI config space.

	  As all changes to the FireWire bus such as enabling and disabling
	  devices cause a bus reset and thereby disable remote DMA for all
	  devices, be sure to have the cable plugged and FireWire enabled on
	  the debugging host before booting the debug target for debugging.

	  This code (~1k) is freed after boot. By then, the firewire stack
	  in charge of the OHCI-1394 controllers should be used instead.

	  See Documentation/debugging-via-ohci1394.txt for more information.
A
Arjan van de Ven 已提交
992

993 994 995 996 997 998 999 1000 1001 1002 1003
config FIREWIRE_OHCI_REMOTE_DMA
	bool "Remote debugging over FireWire with firewire-ohci"
	depends on FIREWIRE_OHCI
	help
	  This option lets you use the FireWire bus for remote debugging
	  with help of the firewire-ohci driver. It enables unfiltered
	  remote DMA in firewire-ohci.
	  See Documentation/debugging-via-ohci1394.txt for more information.

	  If unsure, say N.

1004
config BUILD_DOCSRC
1005 1006 1007 1008 1009 1010 1011 1012
	bool "Build targets in Documentation/ tree"
	depends on HEADERS_CHECK
	help
	  This option attempts to build objects from the source files in the
	  kernel Documentation/ tree.

	  Say N if you are unsure.

1013
config DYNAMIC_DEBUG
J
Jason Baron 已提交
1014
	bool "Enable dynamic printk() support"
1015 1016
	default n
	depends on PRINTK
J
Jason Baron 已提交
1017
	depends on DEBUG_FS
1018 1019 1020 1021
	help

	  Compiles debug level messages into the kernel, which would not
	  otherwise be available at runtime. These messages can then be
J
Jason Baron 已提交
1022 1023 1024 1025
	  enabled/disabled based on various levels of scope - per source file,
	  function, module, format string, and line number. This mechanism
	  implicitly enables all pr_debug() and dev_dbg() calls. The impact of
	  this compile option is a larger kernel text size of about 2%.
1026 1027 1028

	  Usage:

J
Jason Baron 已提交
1029 1030 1031 1032 1033 1034
	  Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
	  which is contained in the 'debugfs' filesystem. Thus, the debugfs
	  filesystem must first be mounted before making use of this feature.
	  We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
	  file contains a list of the debug statements that can be enabled. The
	  format for each line of the file is:
1035

J
Jason Baron 已提交
1036
		filename:lineno [module]function flags format
1037

J
Jason Baron 已提交
1038 1039 1040 1041 1042 1043
	  filename : source file of the debug statement
	  lineno : line number of the debug statement
	  module : module that contains the debug statement
	  function : function that contains the debug statement
          flags : 'p' means the line is turned 'on' for printing
          format : the format used for the debug statement
1044 1045 1046

	  From a live system:

J
Jason Baron 已提交
1047 1048 1049 1050 1051
		nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
		# filename:lineno [module]function flags format
		fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
		fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
		fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
1052

J
Jason Baron 已提交
1053
	  Example usage:
1054

J
Jason Baron 已提交
1055 1056 1057
		// enable the message at line 1603 of file svcsock.c
		nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
						<debugfs>/dynamic_debug/ddebug
1058

J
Jason Baron 已提交
1059 1060 1061
		// enable all the messages in file svcsock.c
		nullarbor:~ # echo -n 'file svcsock.c +p' >
						<debugfs>/dynamic_debug/ddebug
1062

J
Jason Baron 已提交
1063 1064 1065
		// enable all the messages in the NFS server module
		nullarbor:~ # echo -n 'module nfsd +p' >
						<debugfs>/dynamic_debug/ddebug
1066

J
Jason Baron 已提交
1067 1068 1069
		// enable all 12 messages in the function svc_process()
		nullarbor:~ # echo -n 'func svc_process +p' >
						<debugfs>/dynamic_debug/ddebug
1070

J
Jason Baron 已提交
1071 1072 1073
		// disable all 12 messages in the function svc_process()
		nullarbor:~ # echo -n 'func svc_process -p' >
						<debugfs>/dynamic_debug/ddebug
1074

J
Jason Baron 已提交
1075
	  See Documentation/dynamic-debug-howto.txt for additional information.
1076

J
Joerg Roedel 已提交
1077 1078 1079 1080 1081 1082 1083 1084 1085 1086
config DMA_API_DEBUG
	bool "Enable debugging of DMA-API usage"
	depends on HAVE_DMA_API_DEBUG
	help
	  Enable this option to debug the use of the DMA API by device drivers.
	  With this option you will be able to detect common bugs in device
	  drivers like double-freeing of DMA mappings or freeing mappings that
	  were never allocated.
	  This option causes a performance degredation.  Use only if you want
	  to debug device drivers. If unsure, say N.
1087

M
Mathieu Desnoyers 已提交
1088
source "samples/Kconfig"
J
Jason Wessel 已提交
1089 1090

source "lib/Kconfig.kgdb"
1091 1092

source "lib/Kconfig.kmemcheck"