Kconfig.debug 50 KB

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  1. config PRINTK_TIME
  2. bool "Show timing information on printks"
  3. depends on PRINTK
  4. help
  5. Selecting this option causes time stamps of the printk()
  6. messages to be added to the output of the syslog() system
  7. call and at the console.
  8. The timestamp is always recorded internally, and exported
  9. to /dev/kmsg. This flag just specifies if the timestamp should
  10. be included, not that the timestamp is recorded.
  11. The behavior is also controlled by the kernel command line
  12. parameter printk.time=1. See Documentation/kernel-parameters.txt
  13. config DEFAULT_MESSAGE_LOGLEVEL
  14. int "Default message log level (1-7)"
  15. range 1 7
  16. default "4"
  17. help
  18. Default log level for printk statements with no specified priority.
  19. This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
  20. that are auditing their logs closely may want to set it to a lower
  21. priority.
  22. config ENABLE_WARN_DEPRECATED
  23. bool "Enable __deprecated logic"
  24. default y
  25. help
  26. Enable the __deprecated logic in the kernel build.
  27. Disable this to suppress the "warning: 'foo' is deprecated
  28. (declared at kernel/power/somefile.c:1234)" messages.
  29. config ENABLE_MUST_CHECK
  30. bool "Enable __must_check logic"
  31. default y
  32. help
  33. Enable the __must_check logic in the kernel build. Disable this to
  34. suppress the "warning: ignoring return value of 'foo', declared with
  35. attribute warn_unused_result" messages.
  36. config FRAME_WARN
  37. int "Warn for stack frames larger than (needs gcc 4.4)"
  38. range 0 8192
  39. default 1024 if !64BIT
  40. default 2048 if 64BIT
  41. help
  42. Tell gcc to warn at build time for stack frames larger than this.
  43. Setting this too low will cause a lot of warnings.
  44. Setting it to 0 disables the warning.
  45. Requires gcc 4.4
  46. config MAGIC_SYSRQ
  47. bool "Magic SysRq key"
  48. depends on !UML
  49. help
  50. If you say Y here, you will have some control over the system even
  51. if the system crashes for example during kernel debugging (e.g., you
  52. will be able to flush the buffer cache to disk, reboot the system
  53. immediately or dump some status information). This is accomplished
  54. by pressing various keys while holding SysRq (Alt+PrintScreen). It
  55. also works on a serial console (on PC hardware at least), if you
  56. send a BREAK and then within 5 seconds a command keypress. The
  57. keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
  58. unless you really know what this hack does.
  59. config STRIP_ASM_SYMS
  60. bool "Strip assembler-generated symbols during link"
  61. default n
  62. help
  63. Strip internal assembler-generated symbols during a link (symbols
  64. that look like '.Lxxx') so they don't pollute the output of
  65. get_wchan() and suchlike.
  66. config READABLE_ASM
  67. bool "Generate readable assembler code"
  68. depends on DEBUG_KERNEL
  69. help
  70. Disable some compiler optimizations that tend to generate human unreadable
  71. assembler output. This may make the kernel slightly slower, but it helps
  72. to keep kernel developers who have to stare a lot at assembler listings
  73. sane.
  74. config UNUSED_SYMBOLS
  75. bool "Enable unused/obsolete exported symbols"
  76. default y if X86
  77. help
  78. Unused but exported symbols make the kernel needlessly bigger. For
  79. that reason most of these unused exports will soon be removed. This
  80. option is provided temporarily to provide a transition period in case
  81. some external kernel module needs one of these symbols anyway. If you
  82. encounter such a case in your module, consider if you are actually
  83. using the right API. (rationale: since nobody in the kernel is using
  84. this in a module, there is a pretty good chance it's actually the
  85. wrong interface to use). If you really need the symbol, please send a
  86. mail to the linux kernel mailing list mentioning the symbol and why
  87. you really need it, and what the merge plan to the mainline kernel for
  88. your module is.
  89. config DEBUG_FS
  90. bool "Debug Filesystem"
  91. help
  92. debugfs is a virtual file system that kernel developers use to put
  93. debugging files into. Enable this option to be able to read and
  94. write to these files.
  95. For detailed documentation on the debugfs API, see
  96. Documentation/DocBook/filesystems.
  97. If unsure, say N.
  98. config HEADERS_CHECK
  99. bool "Run 'make headers_check' when building vmlinux"
  100. depends on !UML
  101. help
  102. This option will extract the user-visible kernel headers whenever
  103. building the kernel, and will run basic sanity checks on them to
  104. ensure that exported files do not attempt to include files which
  105. were not exported, etc.
  106. If you're making modifications to header files which are
  107. relevant for userspace, say 'Y', and check the headers
  108. exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
  109. your build tree), to make sure they're suitable.
  110. config DEBUG_SECTION_MISMATCH
  111. bool "Enable full Section mismatch analysis"
  112. help
  113. The section mismatch analysis checks if there are illegal
  114. references from one section to another section.
  115. During linktime or runtime, some sections are dropped;
  116. any use of code/data previously in these sections would
  117. most likely result in an oops.
  118. In the code, functions and variables are annotated with
  119. __init, __devinit, etc. (see the full list in include/linux/init.h),
  120. which results in the code/data being placed in specific sections.
  121. The section mismatch analysis is always performed after a full
  122. kernel build, and enabling this option causes the following
  123. additional steps to occur:
  124. - Add the option -fno-inline-functions-called-once to gcc commands.
  125. When inlining a function annotated with __init in a non-init
  126. function, we would lose the section information and thus
  127. the analysis would not catch the illegal reference.
  128. This option tells gcc to inline less (but it does result in
  129. a larger kernel).
  130. - Run the section mismatch analysis for each module/built-in.o file.
  131. When we run the section mismatch analysis on vmlinux.o, we
  132. lose valueble information about where the mismatch was
  133. introduced.
  134. Running the analysis for each module/built-in.o file
  135. tells where the mismatch happens much closer to the
  136. source. The drawback is that the same mismatch is
  137. reported at least twice.
  138. - Enable verbose reporting from modpost in order to help resolve
  139. the section mismatches that are reported.
  140. config DEBUG_KERNEL
  141. bool "Kernel debugging"
  142. help
  143. Say Y here if you are developing drivers or trying to debug and
  144. identify kernel problems.
  145. config DEBUG_SHIRQ
  146. bool "Debug shared IRQ handlers"
  147. depends on DEBUG_KERNEL && GENERIC_HARDIRQS
  148. help
  149. Enable this to generate a spurious interrupt as soon as a shared
  150. interrupt handler is registered, and just before one is deregistered.
  151. Drivers ought to be able to handle interrupts coming in at those
  152. points; some don't and need to be caught.
  153. config LOCKUP_DETECTOR
  154. bool "Detect Hard and Soft Lockups"
  155. depends on DEBUG_KERNEL && !S390
  156. help
  157. Say Y here to enable the kernel to act as a watchdog to detect
  158. hard and soft lockups.
  159. Softlockups are bugs that cause the kernel to loop in kernel
  160. mode for more than 20 seconds, without giving other tasks a
  161. chance to run. The current stack trace is displayed upon
  162. detection and the system will stay locked up.
  163. Hardlockups are bugs that cause the CPU to loop in kernel mode
  164. for more than 10 seconds, without letting other interrupts have a
  165. chance to run. The current stack trace is displayed upon detection
  166. and the system will stay locked up.
  167. The overhead should be minimal. A periodic hrtimer runs to
  168. generate interrupts and kick the watchdog task every 4 seconds.
  169. An NMI is generated every 10 seconds or so to check for hardlockups.
  170. The frequency of hrtimer and NMI events and the soft and hard lockup
  171. thresholds can be controlled through the sysctl watchdog_thresh.
  172. config HARDLOCKUP_DETECTOR
  173. def_bool y
  174. depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
  175. depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
  176. config BOOTPARAM_HARDLOCKUP_PANIC
  177. bool "Panic (Reboot) On Hard Lockups"
  178. depends on HARDLOCKUP_DETECTOR
  179. help
  180. Say Y here to enable the kernel to panic on "hard lockups",
  181. which are bugs that cause the kernel to loop in kernel
  182. mode with interrupts disabled for more than 10 seconds (configurable
  183. using the watchdog_thresh sysctl).
  184. Say N if unsure.
  185. config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
  186. int
  187. depends on HARDLOCKUP_DETECTOR
  188. range 0 1
  189. default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
  190. default 1 if BOOTPARAM_HARDLOCKUP_PANIC
  191. config BOOTPARAM_SOFTLOCKUP_PANIC
  192. bool "Panic (Reboot) On Soft Lockups"
  193. depends on LOCKUP_DETECTOR
  194. help
  195. Say Y here to enable the kernel to panic on "soft lockups",
  196. which are bugs that cause the kernel to loop in kernel
  197. mode for more than 20 seconds (configurable using the watchdog_thresh
  198. sysctl), without giving other tasks a chance to run.
  199. The panic can be used in combination with panic_timeout,
  200. to cause the system to reboot automatically after a
  201. lockup has been detected. This feature is useful for
  202. high-availability systems that have uptime guarantees and
  203. where a lockup must be resolved ASAP.
  204. Say N if unsure.
  205. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  206. int
  207. depends on LOCKUP_DETECTOR
  208. range 0 1
  209. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  210. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  211. config PANIC_ON_OOPS
  212. bool "Panic on Oops" if EXPERT
  213. default n
  214. help
  215. Say Y here to enable the kernel to panic when it oopses. This
  216. has the same effect as setting oops=panic on the kernel command
  217. line.
  218. This feature is useful to ensure that the kernel does not do
  219. anything erroneous after an oops which could result in data
  220. corruption or other issues.
  221. Say N if unsure.
  222. config PANIC_ON_OOPS_VALUE
  223. int
  224. range 0 1
  225. default 0 if !PANIC_ON_OOPS
  226. default 1 if PANIC_ON_OOPS
  227. config DETECT_HUNG_TASK
  228. bool "Detect Hung Tasks"
  229. depends on DEBUG_KERNEL
  230. default LOCKUP_DETECTOR
  231. help
  232. Say Y here to enable the kernel to detect "hung tasks",
  233. which are bugs that cause the task to be stuck in
  234. uninterruptible "D" state indefinitiley.
  235. When a hung task is detected, the kernel will print the
  236. current stack trace (which you should report), but the
  237. task will stay in uninterruptible state. If lockdep is
  238. enabled then all held locks will also be reported. This
  239. feature has negligible overhead.
  240. config DEFAULT_HUNG_TASK_TIMEOUT
  241. int "Default timeout for hung task detection (in seconds)"
  242. depends on DETECT_HUNG_TASK
  243. default 120
  244. help
  245. This option controls the default timeout (in seconds) used
  246. to determine when a task has become non-responsive and should
  247. be considered hung.
  248. It can be adjusted at runtime via the kernel.hung_task_timeout_secs
  249. sysctl or by writing a value to
  250. /proc/sys/kernel/hung_task_timeout_secs.
  251. A timeout of 0 disables the check. The default is two minutes.
  252. Keeping the default should be fine in most cases.
  253. config BOOTPARAM_HUNG_TASK_PANIC
  254. bool "Panic (Reboot) On Hung Tasks"
  255. depends on DETECT_HUNG_TASK
  256. help
  257. Say Y here to enable the kernel to panic on "hung tasks",
  258. which are bugs that cause the kernel to leave a task stuck
  259. in uninterruptible "D" state.
  260. The panic can be used in combination with panic_timeout,
  261. to cause the system to reboot automatically after a
  262. hung task has been detected. This feature is useful for
  263. high-availability systems that have uptime guarantees and
  264. where a hung tasks must be resolved ASAP.
  265. Say N if unsure.
  266. config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  267. int
  268. depends on DETECT_HUNG_TASK
  269. range 0 1
  270. default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  271. default 1 if BOOTPARAM_HUNG_TASK_PANIC
  272. config SCHED_DEBUG
  273. bool "Collect scheduler debugging info"
  274. depends on DEBUG_KERNEL && PROC_FS
  275. default y
  276. help
  277. If you say Y here, the /proc/sched_debug file will be provided
  278. that can help debug the scheduler. The runtime overhead of this
  279. option is minimal.
  280. config SCHEDSTATS
  281. bool "Collect scheduler statistics"
  282. depends on DEBUG_KERNEL && PROC_FS
  283. help
  284. If you say Y here, additional code will be inserted into the
  285. scheduler and related routines to collect statistics about
  286. scheduler behavior and provide them in /proc/schedstat. These
  287. stats may be useful for both tuning and debugging the scheduler
  288. If you aren't debugging the scheduler or trying to tune a specific
  289. application, you can say N to avoid the very slight overhead
  290. this adds.
  291. config TIMER_STATS
  292. bool "Collect kernel timers statistics"
  293. depends on DEBUG_KERNEL && PROC_FS
  294. help
  295. If you say Y here, additional code will be inserted into the
  296. timer routines to collect statistics about kernel timers being
  297. reprogrammed. The statistics can be read from /proc/timer_stats.
  298. The statistics collection is started by writing 1 to /proc/timer_stats,
  299. writing 0 stops it. This feature is useful to collect information
  300. about timer usage patterns in kernel and userspace. This feature
  301. is lightweight if enabled in the kernel config but not activated
  302. (it defaults to deactivated on bootup and will only be activated
  303. if some application like powertop activates it explicitly).
  304. config DEBUG_OBJECTS
  305. bool "Debug object operations"
  306. depends on DEBUG_KERNEL
  307. help
  308. If you say Y here, additional code will be inserted into the
  309. kernel to track the life time of various objects and validate
  310. the operations on those objects.
  311. config DEBUG_OBJECTS_SELFTEST
  312. bool "Debug objects selftest"
  313. depends on DEBUG_OBJECTS
  314. help
  315. This enables the selftest of the object debug code.
  316. config DEBUG_OBJECTS_FREE
  317. bool "Debug objects in freed memory"
  318. depends on DEBUG_OBJECTS
  319. help
  320. This enables checks whether a k/v free operation frees an area
  321. which contains an object which has not been deactivated
  322. properly. This can make kmalloc/kfree-intensive workloads
  323. much slower.
  324. config DEBUG_OBJECTS_TIMERS
  325. bool "Debug timer objects"
  326. depends on DEBUG_OBJECTS
  327. help
  328. If you say Y here, additional code will be inserted into the
  329. timer routines to track the life time of timer objects and
  330. validate the timer operations.
  331. config DEBUG_OBJECTS_WORK
  332. bool "Debug work objects"
  333. depends on DEBUG_OBJECTS
  334. help
  335. If you say Y here, additional code will be inserted into the
  336. work queue routines to track the life time of work objects and
  337. validate the work operations.
  338. config DEBUG_OBJECTS_RCU_HEAD
  339. bool "Debug RCU callbacks objects"
  340. depends on DEBUG_OBJECTS
  341. help
  342. Enable this to turn on debugging of RCU list heads (call_rcu() usage).
  343. config DEBUG_OBJECTS_PERCPU_COUNTER
  344. bool "Debug percpu counter objects"
  345. depends on DEBUG_OBJECTS
  346. help
  347. If you say Y here, additional code will be inserted into the
  348. percpu counter routines to track the life time of percpu counter
  349. objects and validate the percpu counter operations.
  350. config DEBUG_OBJECTS_ENABLE_DEFAULT
  351. int "debug_objects bootup default value (0-1)"
  352. range 0 1
  353. default "1"
  354. depends on DEBUG_OBJECTS
  355. help
  356. Debug objects boot parameter default value
  357. config DEBUG_SLAB
  358. bool "Debug slab memory allocations"
  359. depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
  360. help
  361. Say Y here to have the kernel do limited verification on memory
  362. allocation as well as poisoning memory on free to catch use of freed
  363. memory. This can make kmalloc/kfree-intensive workloads much slower.
  364. config DEBUG_SLAB_LEAK
  365. bool "Memory leak debugging"
  366. depends on DEBUG_SLAB
  367. config SLUB_DEBUG_ON
  368. bool "SLUB debugging on by default"
  369. depends on SLUB && SLUB_DEBUG && !KMEMCHECK
  370. default n
  371. help
  372. Boot with debugging on by default. SLUB boots by default with
  373. the runtime debug capabilities switched off. Enabling this is
  374. equivalent to specifying the "slub_debug" parameter on boot.
  375. There is no support for more fine grained debug control like
  376. possible with slub_debug=xxx. SLUB debugging may be switched
  377. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  378. "slub_debug=-".
  379. config SLUB_STATS
  380. default n
  381. bool "Enable SLUB performance statistics"
  382. depends on SLUB && SYSFS
  383. help
  384. SLUB statistics are useful to debug SLUBs allocation behavior in
  385. order find ways to optimize the allocator. This should never be
  386. enabled for production use since keeping statistics slows down
  387. the allocator by a few percentage points. The slabinfo command
  388. supports the determination of the most active slabs to figure
  389. out which slabs are relevant to a particular load.
  390. Try running: slabinfo -DA
  391. config HAVE_DEBUG_KMEMLEAK
  392. bool
  393. config DEBUG_KMEMLEAK
  394. bool "Kernel memory leak detector"
  395. depends on DEBUG_KERNEL && EXPERIMENTAL && HAVE_DEBUG_KMEMLEAK
  396. select DEBUG_FS
  397. select STACKTRACE if STACKTRACE_SUPPORT
  398. select KALLSYMS
  399. select CRC32
  400. help
  401. Say Y here if you want to enable the memory leak
  402. detector. The memory allocation/freeing is traced in a way
  403. similar to the Boehm's conservative garbage collector, the
  404. difference being that the orphan objects are not freed but
  405. only shown in /sys/kernel/debug/kmemleak. Enabling this
  406. feature will introduce an overhead to memory
  407. allocations. See Documentation/kmemleak.txt for more
  408. details.
  409. Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  410. of finding leaks due to the slab objects poisoning.
  411. In order to access the kmemleak file, debugfs needs to be
  412. mounted (usually at /sys/kernel/debug).
  413. config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
  414. int "Maximum kmemleak early log entries"
  415. depends on DEBUG_KMEMLEAK
  416. range 200 40000
  417. default 400
  418. help
  419. Kmemleak must track all the memory allocations to avoid
  420. reporting false positives. Since memory may be allocated or
  421. freed before kmemleak is initialised, an early log buffer is
  422. used to store these actions. If kmemleak reports "early log
  423. buffer exceeded", please increase this value.
  424. config DEBUG_KMEMLEAK_TEST
  425. tristate "Simple test for the kernel memory leak detector"
  426. depends on DEBUG_KMEMLEAK && m
  427. help
  428. This option enables a module that explicitly leaks memory.
  429. If unsure, say N.
  430. config DEBUG_KMEMLEAK_DEFAULT_OFF
  431. bool "Default kmemleak to off"
  432. depends on DEBUG_KMEMLEAK
  433. help
  434. Say Y here to disable kmemleak by default. It can then be enabled
  435. on the command line via kmemleak=on.
  436. config DEBUG_PREEMPT
  437. bool "Debug preemptible kernel"
  438. depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
  439. default y
  440. help
  441. If you say Y here then the kernel will use a debug variant of the
  442. commonly used smp_processor_id() function and will print warnings
  443. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  444. will detect preemption count underflows.
  445. config DEBUG_RT_MUTEXES
  446. bool "RT Mutex debugging, deadlock detection"
  447. depends on DEBUG_KERNEL && RT_MUTEXES
  448. help
  449. This allows rt mutex semantics violations and rt mutex related
  450. deadlocks (lockups) to be detected and reported automatically.
  451. config DEBUG_PI_LIST
  452. bool
  453. default y
  454. depends on DEBUG_RT_MUTEXES
  455. config RT_MUTEX_TESTER
  456. bool "Built-in scriptable tester for rt-mutexes"
  457. depends on DEBUG_KERNEL && RT_MUTEXES
  458. help
  459. This option enables a rt-mutex tester.
  460. config DEBUG_SPINLOCK
  461. bool "Spinlock and rw-lock debugging: basic checks"
  462. depends on DEBUG_KERNEL
  463. select UNINLINE_SPIN_UNLOCK
  464. help
  465. Say Y here and build SMP to catch missing spinlock initialization
  466. and certain other kinds of spinlock errors commonly made. This is
  467. best used in conjunction with the NMI watchdog so that spinlock
  468. deadlocks are also debuggable.
  469. config DEBUG_MUTEXES
  470. bool "Mutex debugging: basic checks"
  471. depends on DEBUG_KERNEL
  472. help
  473. This feature allows mutex semantics violations to be detected and
  474. reported.
  475. config DEBUG_LOCK_ALLOC
  476. bool "Lock debugging: detect incorrect freeing of live locks"
  477. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  478. select DEBUG_SPINLOCK
  479. select DEBUG_MUTEXES
  480. select LOCKDEP
  481. help
  482. This feature will check whether any held lock (spinlock, rwlock,
  483. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  484. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  485. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  486. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  487. held during task exit.
  488. config PROVE_LOCKING
  489. bool "Lock debugging: prove locking correctness"
  490. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  491. select LOCKDEP
  492. select DEBUG_SPINLOCK
  493. select DEBUG_MUTEXES
  494. select DEBUG_LOCK_ALLOC
  495. select TRACE_IRQFLAGS
  496. default n
  497. help
  498. This feature enables the kernel to prove that all locking
  499. that occurs in the kernel runtime is mathematically
  500. correct: that under no circumstance could an arbitrary (and
  501. not yet triggered) combination of observed locking
  502. sequences (on an arbitrary number of CPUs, running an
  503. arbitrary number of tasks and interrupt contexts) cause a
  504. deadlock.
  505. In short, this feature enables the kernel to report locking
  506. related deadlocks before they actually occur.
  507. The proof does not depend on how hard and complex a
  508. deadlock scenario would be to trigger: how many
  509. participant CPUs, tasks and irq-contexts would be needed
  510. for it to trigger. The proof also does not depend on
  511. timing: if a race and a resulting deadlock is possible
  512. theoretically (no matter how unlikely the race scenario
  513. is), it will be proven so and will immediately be
  514. reported by the kernel (once the event is observed that
  515. makes the deadlock theoretically possible).
  516. If a deadlock is impossible (i.e. the locking rules, as
  517. observed by the kernel, are mathematically correct), the
  518. kernel reports nothing.
  519. NOTE: this feature can also be enabled for rwlocks, mutexes
  520. and rwsems - in which case all dependencies between these
  521. different locking variants are observed and mapped too, and
  522. the proof of observed correctness is also maintained for an
  523. arbitrary combination of these separate locking variants.
  524. For more details, see Documentation/lockdep-design.txt.
  525. config PROVE_RCU
  526. bool "RCU debugging: prove RCU correctness"
  527. depends on PROVE_LOCKING
  528. default n
  529. help
  530. This feature enables lockdep extensions that check for correct
  531. use of RCU APIs. This is currently under development. Say Y
  532. if you want to debug RCU usage or help work on the PROVE_RCU
  533. feature.
  534. Say N if you are unsure.
  535. config PROVE_RCU_REPEATEDLY
  536. bool "RCU debugging: don't disable PROVE_RCU on first splat"
  537. depends on PROVE_RCU
  538. default n
  539. help
  540. By itself, PROVE_RCU will disable checking upon issuing the
  541. first warning (or "splat"). This feature prevents such
  542. disabling, allowing multiple RCU-lockdep warnings to be printed
  543. on a single reboot.
  544. Say Y to allow multiple RCU-lockdep warnings per boot.
  545. Say N if you are unsure.
  546. config PROVE_RCU_DELAY
  547. bool "RCU debugging: preemptible RCU race provocation"
  548. depends on DEBUG_KERNEL && PREEMPT_RCU
  549. default n
  550. help
  551. There is a class of races that involve an unlikely preemption
  552. of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
  553. been set to INT_MIN. This feature inserts a delay at that
  554. point to increase the probability of these races.
  555. Say Y to increase probability of preemption of __rcu_read_unlock().
  556. Say N if you are unsure.
  557. config SPARSE_RCU_POINTER
  558. bool "RCU debugging: sparse-based checks for pointer usage"
  559. default n
  560. help
  561. This feature enables the __rcu sparse annotation for
  562. RCU-protected pointers. This annotation will cause sparse
  563. to flag any non-RCU used of annotated pointers. This can be
  564. helpful when debugging RCU usage. Please note that this feature
  565. is not intended to enforce code cleanliness; it is instead merely
  566. a debugging aid.
  567. Say Y to make sparse flag questionable use of RCU-protected pointers
  568. Say N if you are unsure.
  569. config LOCKDEP
  570. bool
  571. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  572. select STACKTRACE
  573. select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
  574. select KALLSYMS
  575. select KALLSYMS_ALL
  576. config LOCK_STAT
  577. bool "Lock usage statistics"
  578. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  579. select LOCKDEP
  580. select DEBUG_SPINLOCK
  581. select DEBUG_MUTEXES
  582. select DEBUG_LOCK_ALLOC
  583. default n
  584. help
  585. This feature enables tracking lock contention points
  586. For more details, see Documentation/lockstat.txt
  587. This also enables lock events required by "perf lock",
  588. subcommand of perf.
  589. If you want to use "perf lock", you also need to turn on
  590. CONFIG_EVENT_TRACING.
  591. CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
  592. (CONFIG_LOCKDEP defines "acquire" and "release" events.)
  593. config DEBUG_LOCKDEP
  594. bool "Lock dependency engine debugging"
  595. depends on DEBUG_KERNEL && LOCKDEP
  596. help
  597. If you say Y here, the lock dependency engine will do
  598. additional runtime checks to debug itself, at the price
  599. of more runtime overhead.
  600. config TRACE_IRQFLAGS
  601. bool
  602. help
  603. Enables hooks to interrupt enabling and disabling for
  604. either tracing or lock debugging.
  605. config DEBUG_ATOMIC_SLEEP
  606. bool "Sleep inside atomic section checking"
  607. select PREEMPT_COUNT
  608. depends on DEBUG_KERNEL
  609. help
  610. If you say Y here, various routines which may sleep will become very
  611. noisy if they are called inside atomic sections: when a spinlock is
  612. held, inside an rcu read side critical section, inside preempt disabled
  613. sections, inside an interrupt, etc...
  614. config DEBUG_LOCKING_API_SELFTESTS
  615. bool "Locking API boot-time self-tests"
  616. depends on DEBUG_KERNEL
  617. help
  618. Say Y here if you want the kernel to run a short self-test during
  619. bootup. The self-test checks whether common types of locking bugs
  620. are detected by debugging mechanisms or not. (if you disable
  621. lock debugging then those bugs wont be detected of course.)
  622. The following locking APIs are covered: spinlocks, rwlocks,
  623. mutexes and rwsems.
  624. config STACKTRACE
  625. bool
  626. depends on STACKTRACE_SUPPORT
  627. config DEBUG_STACK_USAGE
  628. bool "Stack utilization instrumentation"
  629. depends on DEBUG_KERNEL && !IA64 && !PARISC
  630. help
  631. Enables the display of the minimum amount of free stack which each
  632. task has ever had available in the sysrq-T and sysrq-P debug output.
  633. This option will slow down process creation somewhat.
  634. config DEBUG_KOBJECT
  635. bool "kobject debugging"
  636. depends on DEBUG_KERNEL
  637. help
  638. If you say Y here, some extra kobject debugging messages will be sent
  639. to the syslog.
  640. config DEBUG_HIGHMEM
  641. bool "Highmem debugging"
  642. depends on DEBUG_KERNEL && HIGHMEM
  643. help
  644. This options enables addition error checking for high memory systems.
  645. Disable for production systems.
  646. config HAVE_DEBUG_BUGVERBOSE
  647. bool
  648. config DEBUG_BUGVERBOSE
  649. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
  650. depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
  651. default y
  652. help
  653. Say Y here to make BUG() panics output the file name and line number
  654. of the BUG call as well as the EIP and oops trace. This aids
  655. debugging but costs about 70-100K of memory.
  656. config DEBUG_INFO
  657. bool "Compile the kernel with debug info"
  658. depends on DEBUG_KERNEL
  659. help
  660. If you say Y here the resulting kernel image will include
  661. debugging info resulting in a larger kernel image.
  662. This adds debug symbols to the kernel and modules (gcc -g), and
  663. is needed if you intend to use kernel crashdump or binary object
  664. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  665. Say Y here only if you plan to debug the kernel.
  666. If unsure, say N.
  667. config DEBUG_INFO_REDUCED
  668. bool "Reduce debugging information"
  669. depends on DEBUG_INFO
  670. help
  671. If you say Y here gcc is instructed to generate less debugging
  672. information for structure types. This means that tools that
  673. need full debugging information (like kgdb or systemtap) won't
  674. be happy. But if you merely need debugging information to
  675. resolve line numbers there is no loss. Advantage is that
  676. build directory object sizes shrink dramatically over a full
  677. DEBUG_INFO build and compile times are reduced too.
  678. Only works with newer gcc versions.
  679. config DEBUG_VM
  680. bool "Debug VM"
  681. depends on DEBUG_KERNEL
  682. help
  683. Enable this to turn on extended checks in the virtual-memory system
  684. that may impact performance.
  685. If unsure, say N.
  686. config DEBUG_VM_RB
  687. bool "Debug VM red-black trees"
  688. depends on DEBUG_VM
  689. help
  690. Enable this to turn on more extended checks in the virtual-memory
  691. system that may impact performance.
  692. If unsure, say N.
  693. config DEBUG_VIRTUAL
  694. bool "Debug VM translations"
  695. depends on DEBUG_KERNEL && X86
  696. help
  697. Enable some costly sanity checks in virtual to page code. This can
  698. catch mistakes with virt_to_page() and friends.
  699. If unsure, say N.
  700. config DEBUG_NOMMU_REGIONS
  701. bool "Debug the global anon/private NOMMU mapping region tree"
  702. depends on DEBUG_KERNEL && !MMU
  703. help
  704. This option causes the global tree of anonymous and private mapping
  705. regions to be regularly checked for invalid topology.
  706. config DEBUG_WRITECOUNT
  707. bool "Debug filesystem writers count"
  708. depends on DEBUG_KERNEL
  709. help
  710. Enable this to catch wrong use of the writers count in struct
  711. vfsmount. This will increase the size of each file struct by
  712. 32 bits.
  713. If unsure, say N.
  714. config DEBUG_MEMORY_INIT
  715. bool "Debug memory initialisation" if EXPERT
  716. default !EXPERT
  717. help
  718. Enable this for additional checks during memory initialisation.
  719. The sanity checks verify aspects of the VM such as the memory model
  720. and other information provided by the architecture. Verbose
  721. information will be printed at KERN_DEBUG loglevel depending
  722. on the mminit_loglevel= command-line option.
  723. If unsure, say Y
  724. config DEBUG_LIST
  725. bool "Debug linked list manipulation"
  726. depends on DEBUG_KERNEL
  727. help
  728. Enable this to turn on extended checks in the linked-list
  729. walking routines.
  730. If unsure, say N.
  731. config TEST_LIST_SORT
  732. bool "Linked list sorting test"
  733. depends on DEBUG_KERNEL
  734. help
  735. Enable this to turn on 'list_sort()' function test. This test is
  736. executed only once during system boot, so affects only boot time.
  737. If unsure, say N.
  738. config DEBUG_SG
  739. bool "Debug SG table operations"
  740. depends on DEBUG_KERNEL
  741. help
  742. Enable this to turn on checks on scatter-gather tables. This can
  743. help find problems with drivers that do not properly initialize
  744. their sg tables.
  745. If unsure, say N.
  746. config DEBUG_NOTIFIERS
  747. bool "Debug notifier call chains"
  748. depends on DEBUG_KERNEL
  749. help
  750. Enable this to turn on sanity checking for notifier call chains.
  751. This is most useful for kernel developers to make sure that
  752. modules properly unregister themselves from notifier chains.
  753. This is a relatively cheap check but if you care about maximum
  754. performance, say N.
  755. config DEBUG_CREDENTIALS
  756. bool "Debug credential management"
  757. depends on DEBUG_KERNEL
  758. help
  759. Enable this to turn on some debug checking for credential
  760. management. The additional code keeps track of the number of
  761. pointers from task_structs to any given cred struct, and checks to
  762. see that this number never exceeds the usage count of the cred
  763. struct.
  764. Furthermore, if SELinux is enabled, this also checks that the
  765. security pointer in the cred struct is never seen to be invalid.
  766. If unsure, say N.
  767. #
  768. # Select this config option from the architecture Kconfig, if it
  769. # is preferred to always offer frame pointers as a config
  770. # option on the architecture (regardless of KERNEL_DEBUG):
  771. #
  772. config ARCH_WANT_FRAME_POINTERS
  773. bool
  774. help
  775. config FRAME_POINTER
  776. bool "Compile the kernel with frame pointers"
  777. depends on DEBUG_KERNEL && \
  778. (CRIS || M68K || FRV || UML || \
  779. AVR32 || SUPERH || BLACKFIN || MN10300) || \
  780. ARCH_WANT_FRAME_POINTERS
  781. default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
  782. help
  783. If you say Y here the resulting kernel image will be slightly
  784. larger and slower, but it gives very useful debugging information
  785. in case of kernel bugs. (precise oopses/stacktraces/warnings)
  786. config BOOT_PRINTK_DELAY
  787. bool "Delay each boot printk message by N milliseconds"
  788. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  789. help
  790. This build option allows you to read kernel boot messages
  791. by inserting a short delay after each one. The delay is
  792. specified in milliseconds on the kernel command line,
  793. using "boot_delay=N".
  794. It is likely that you would also need to use "lpj=M" to preset
  795. the "loops per jiffie" value.
  796. See a previous boot log for the "lpj" value to use for your
  797. system, and then set "lpj=M" before setting "boot_delay=N".
  798. NOTE: Using this option may adversely affect SMP systems.
  799. I.e., processors other than the first one may not boot up.
  800. BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
  801. what it believes to be lockup conditions.
  802. config RCU_TORTURE_TEST
  803. tristate "torture tests for RCU"
  804. depends on DEBUG_KERNEL
  805. default n
  806. help
  807. This option provides a kernel module that runs torture tests
  808. on the RCU infrastructure. The kernel module may be built
  809. after the fact on the running kernel to be tested, if desired.
  810. Say Y here if you want RCU torture tests to be built into
  811. the kernel.
  812. Say M if you want the RCU torture tests to build as a module.
  813. Say N if you are unsure.
  814. config RCU_TORTURE_TEST_RUNNABLE
  815. bool "torture tests for RCU runnable by default"
  816. depends on RCU_TORTURE_TEST = y
  817. default n
  818. help
  819. This option provides a way to build the RCU torture tests
  820. directly into the kernel without them starting up at boot
  821. time. You can use /proc/sys/kernel/rcutorture_runnable
  822. to manually override this setting. This /proc file is
  823. available only when the RCU torture tests have been built
  824. into the kernel.
  825. Say Y here if you want the RCU torture tests to start during
  826. boot (you probably don't).
  827. Say N here if you want the RCU torture tests to start only
  828. after being manually enabled via /proc.
  829. config RCU_CPU_STALL_TIMEOUT
  830. int "RCU CPU stall timeout in seconds"
  831. depends on TREE_RCU || TREE_PREEMPT_RCU
  832. range 3 300
  833. default 60
  834. help
  835. If a given RCU grace period extends more than the specified
  836. number of seconds, a CPU stall warning is printed. If the
  837. RCU grace period persists, additional CPU stall warnings are
  838. printed at more widely spaced intervals.
  839. config RCU_CPU_STALL_VERBOSE
  840. bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
  841. depends on TREE_PREEMPT_RCU
  842. default y
  843. help
  844. This option causes RCU to printk detailed per-task information
  845. for any tasks that are stalling the current RCU grace period.
  846. Say N if you are unsure.
  847. Say Y if you want to enable such checks.
  848. config RCU_CPU_STALL_INFO
  849. bool "Print additional diagnostics on RCU CPU stall"
  850. depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
  851. default n
  852. help
  853. For each stalled CPU that is aware of the current RCU grace
  854. period, print out additional per-CPU diagnostic information
  855. regarding scheduling-clock ticks, idle state, and,
  856. for RCU_FAST_NO_HZ kernels, idle-entry state.
  857. Say N if you are unsure.
  858. Say Y if you want to enable such diagnostics.
  859. config RCU_TRACE
  860. bool "Enable tracing for RCU"
  861. depends on DEBUG_KERNEL
  862. help
  863. This option provides tracing in RCU which presents stats
  864. in debugfs for debugging RCU implementation.
  865. Say Y here if you want to enable RCU tracing
  866. Say N if you are unsure.
  867. config KPROBES_SANITY_TEST
  868. bool "Kprobes sanity tests"
  869. depends on DEBUG_KERNEL
  870. depends on KPROBES
  871. default n
  872. help
  873. This option provides for testing basic kprobes functionality on
  874. boot. A sample kprobe, jprobe and kretprobe are inserted and
  875. verified for functionality.
  876. Say N if you are unsure.
  877. config BACKTRACE_SELF_TEST
  878. tristate "Self test for the backtrace code"
  879. depends on DEBUG_KERNEL
  880. default n
  881. help
  882. This option provides a kernel module that can be used to test
  883. the kernel stack backtrace code. This option is not useful
  884. for distributions or general kernels, but only for kernel
  885. developers working on architecture code.
  886. Note that if you want to also test saved backtraces, you will
  887. have to enable STACKTRACE as well.
  888. Say N if you are unsure.
  889. config DEBUG_BLOCK_EXT_DEVT
  890. bool "Force extended block device numbers and spread them"
  891. depends on DEBUG_KERNEL
  892. depends on BLOCK
  893. default n
  894. help
  895. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  896. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  897. YOU ARE DOING. Distros, please enable this and fix whatever
  898. is broken.
  899. Conventionally, block device numbers are allocated from
  900. predetermined contiguous area. However, extended block area
  901. may introduce non-contiguous block device numbers. This
  902. option forces most block device numbers to be allocated from
  903. the extended space and spreads them to discover kernel or
  904. userland code paths which assume predetermined contiguous
  905. device number allocation.
  906. Note that turning on this debug option shuffles all the
  907. device numbers for all IDE and SCSI devices including libata
  908. ones, so root partition specified using device number
  909. directly (via rdev or root=MAJ:MIN) won't work anymore.
  910. Textual device names (root=/dev/sdXn) will continue to work.
  911. Say N if you are unsure.
  912. config DEBUG_FORCE_WEAK_PER_CPU
  913. bool "Force weak per-cpu definitions"
  914. depends on DEBUG_KERNEL
  915. help
  916. s390 and alpha require percpu variables in modules to be
  917. defined weak to work around addressing range issue which
  918. puts the following two restrictions on percpu variable
  919. definitions.
  920. 1. percpu symbols must be unique whether static or not
  921. 2. percpu variables can't be defined inside a function
  922. To ensure that generic code follows the above rules, this
  923. option forces all percpu variables to be defined as weak.
  924. config DEBUG_PER_CPU_MAPS
  925. bool "Debug access to per_cpu maps"
  926. depends on DEBUG_KERNEL
  927. depends on SMP
  928. help
  929. Say Y to verify that the per_cpu map being accessed has
  930. been set up. This adds a fair amount of code to kernel memory
  931. and decreases performance.
  932. Say N if unsure.
  933. config LKDTM
  934. tristate "Linux Kernel Dump Test Tool Module"
  935. depends on DEBUG_FS
  936. depends on BLOCK
  937. default n
  938. help
  939. This module enables testing of the different dumping mechanisms by
  940. inducing system failures at predefined crash points.
  941. If you don't need it: say N
  942. Choose M here to compile this code as a module. The module will be
  943. called lkdtm.
  944. Documentation on how to use the module can be found in
  945. Documentation/fault-injection/provoke-crashes.txt
  946. config NOTIFIER_ERROR_INJECTION
  947. tristate "Notifier error injection"
  948. depends on DEBUG_KERNEL
  949. select DEBUG_FS
  950. help
  951. This option provides the ability to inject artifical errors to
  952. specified notifier chain callbacks. It is useful to test the error
  953. handling of notifier call chain failures.
  954. Say N if unsure.
  955. config CPU_NOTIFIER_ERROR_INJECT
  956. tristate "CPU notifier error injection module"
  957. depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
  958. help
  959. This option provides a kernel module that can be used to test
  960. the error handling of the cpu notifiers by injecting artifical
  961. errors to CPU notifier chain callbacks. It is controlled through
  962. debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
  963. If the notifier call chain should be failed with some events
  964. notified, write the error code to "actions/<notifier event>/error".
  965. Example: Inject CPU offline error (-1 == -EPERM)
  966. # cd /sys/kernel/debug/notifier-error-inject/cpu
  967. # echo -1 > actions/CPU_DOWN_PREPARE/error
  968. # echo 0 > /sys/devices/system/cpu/cpu1/online
  969. bash: echo: write error: Operation not permitted
  970. To compile this code as a module, choose M here: the module will
  971. be called cpu-notifier-error-inject.
  972. If unsure, say N.
  973. config PM_NOTIFIER_ERROR_INJECT
  974. tristate "PM notifier error injection module"
  975. depends on PM && NOTIFIER_ERROR_INJECTION
  976. default m if PM_DEBUG
  977. help
  978. This option provides the ability to inject artifical errors to
  979. PM notifier chain callbacks. It is controlled through debugfs
  980. interface /sys/kernel/debug/notifier-error-inject/pm
  981. If the notifier call chain should be failed with some events
  982. notified, write the error code to "actions/<notifier event>/error".
  983. Example: Inject PM suspend error (-12 = -ENOMEM)
  984. # cd /sys/kernel/debug/notifier-error-inject/pm/
  985. # echo -12 > actions/PM_SUSPEND_PREPARE/error
  986. # echo mem > /sys/power/state
  987. bash: echo: write error: Cannot allocate memory
  988. To compile this code as a module, choose M here: the module will
  989. be called pm-notifier-error-inject.
  990. If unsure, say N.
  991. config MEMORY_NOTIFIER_ERROR_INJECT
  992. tristate "Memory hotplug notifier error injection module"
  993. depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
  994. help
  995. This option provides the ability to inject artifical errors to
  996. memory hotplug notifier chain callbacks. It is controlled through
  997. debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
  998. If the notifier call chain should be failed with some events
  999. notified, write the error code to "actions/<notifier event>/error".
  1000. Example: Inject memory hotplug offline error (-12 == -ENOMEM)
  1001. # cd /sys/kernel/debug/notifier-error-inject/memory
  1002. # echo -12 > actions/MEM_GOING_OFFLINE/error
  1003. # echo offline > /sys/devices/system/memory/memoryXXX/state
  1004. bash: echo: write error: Cannot allocate memory
  1005. To compile this code as a module, choose M here: the module will
  1006. be called pSeries-reconfig-notifier-error-inject.
  1007. If unsure, say N.
  1008. config PSERIES_RECONFIG_NOTIFIER_ERROR_INJECT
  1009. tristate "pSeries reconfig notifier error injection module"
  1010. depends on PPC_PSERIES && NOTIFIER_ERROR_INJECTION
  1011. help
  1012. This option provides the ability to inject artifical errors to
  1013. pSeries reconfig notifier chain callbacks. It is controlled
  1014. through debugfs interface under
  1015. /sys/kernel/debug/notifier-error-inject/pSeries-reconfig/
  1016. If the notifier call chain should be failed with some events
  1017. notified, write the error code to "actions/<notifier event>/error".
  1018. To compile this code as a module, choose M here: the module will
  1019. be called memory-notifier-error-inject.
  1020. If unsure, say N.
  1021. config FAULT_INJECTION
  1022. bool "Fault-injection framework"
  1023. depends on DEBUG_KERNEL
  1024. help
  1025. Provide fault-injection framework.
  1026. For more details, see Documentation/fault-injection/.
  1027. config FAILSLAB
  1028. bool "Fault-injection capability for kmalloc"
  1029. depends on FAULT_INJECTION
  1030. depends on SLAB || SLUB
  1031. help
  1032. Provide fault-injection capability for kmalloc.
  1033. config FAIL_PAGE_ALLOC
  1034. bool "Fault-injection capabilitiy for alloc_pages()"
  1035. depends on FAULT_INJECTION
  1036. help
  1037. Provide fault-injection capability for alloc_pages().
  1038. config FAIL_MAKE_REQUEST
  1039. bool "Fault-injection capability for disk IO"
  1040. depends on FAULT_INJECTION && BLOCK
  1041. help
  1042. Provide fault-injection capability for disk IO.
  1043. config FAIL_IO_TIMEOUT
  1044. bool "Fault-injection capability for faking disk interrupts"
  1045. depends on FAULT_INJECTION && BLOCK
  1046. help
  1047. Provide fault-injection capability on end IO handling. This
  1048. will make the block layer "forget" an interrupt as configured,
  1049. thus exercising the error handling.
  1050. Only works with drivers that use the generic timeout handling,
  1051. for others it wont do anything.
  1052. config FAIL_MMC_REQUEST
  1053. bool "Fault-injection capability for MMC IO"
  1054. select DEBUG_FS
  1055. depends on FAULT_INJECTION && MMC
  1056. help
  1057. Provide fault-injection capability for MMC IO.
  1058. This will make the mmc core return data errors. This is
  1059. useful to test the error handling in the mmc block device
  1060. and to test how the mmc host driver handles retries from
  1061. the block device.
  1062. config FAULT_INJECTION_DEBUG_FS
  1063. bool "Debugfs entries for fault-injection capabilities"
  1064. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  1065. help
  1066. Enable configuration of fault-injection capabilities via debugfs.
  1067. config FAULT_INJECTION_STACKTRACE_FILTER
  1068. bool "stacktrace filter for fault-injection capabilities"
  1069. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  1070. depends on !X86_64
  1071. select STACKTRACE
  1072. select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  1073. help
  1074. Provide stacktrace filter for fault-injection capabilities
  1075. config LATENCYTOP
  1076. bool "Latency measuring infrastructure"
  1077. depends on HAVE_LATENCYTOP_SUPPORT
  1078. depends on DEBUG_KERNEL
  1079. depends on STACKTRACE_SUPPORT
  1080. depends on PROC_FS
  1081. select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  1082. select KALLSYMS
  1083. select KALLSYMS_ALL
  1084. select STACKTRACE
  1085. select SCHEDSTATS
  1086. select SCHED_DEBUG
  1087. help
  1088. Enable this option if you want to use the LatencyTOP tool
  1089. to find out which userspace is blocking on what kernel operations.
  1090. source mm/Kconfig.debug
  1091. source kernel/trace/Kconfig
  1092. config RBTREE_TEST
  1093. tristate "Red-Black tree test"
  1094. depends on m && DEBUG_KERNEL
  1095. help
  1096. A benchmark measuring the performance of the rbtree library.
  1097. Also includes rbtree invariant checks.
  1098. config INTERVAL_TREE_TEST
  1099. tristate "Interval tree test"
  1100. depends on m && DEBUG_KERNEL
  1101. help
  1102. A benchmark measuring the performance of the interval tree library
  1103. config PROVIDE_OHCI1394_DMA_INIT
  1104. bool "Remote debugging over FireWire early on boot"
  1105. depends on PCI && X86
  1106. help
  1107. If you want to debug problems which hang or crash the kernel early
  1108. on boot and the crashing machine has a FireWire port, you can use
  1109. this feature to remotely access the memory of the crashed machine
  1110. over FireWire. This employs remote DMA as part of the OHCI1394
  1111. specification which is now the standard for FireWire controllers.
  1112. With remote DMA, you can monitor the printk buffer remotely using
  1113. firescope and access all memory below 4GB using fireproxy from gdb.
  1114. Even controlling a kernel debugger is possible using remote DMA.
  1115. Usage:
  1116. If ohci1394_dma=early is used as boot parameter, it will initialize
  1117. all OHCI1394 controllers which are found in the PCI config space.
  1118. As all changes to the FireWire bus such as enabling and disabling
  1119. devices cause a bus reset and thereby disable remote DMA for all
  1120. devices, be sure to have the cable plugged and FireWire enabled on
  1121. the debugging host before booting the debug target for debugging.
  1122. This code (~1k) is freed after boot. By then, the firewire stack
  1123. in charge of the OHCI-1394 controllers should be used instead.
  1124. See Documentation/debugging-via-ohci1394.txt for more information.
  1125. config FIREWIRE_OHCI_REMOTE_DMA
  1126. bool "Remote debugging over FireWire with firewire-ohci"
  1127. depends on FIREWIRE_OHCI
  1128. help
  1129. This option lets you use the FireWire bus for remote debugging
  1130. with help of the firewire-ohci driver. It enables unfiltered
  1131. remote DMA in firewire-ohci.
  1132. See Documentation/debugging-via-ohci1394.txt for more information.
  1133. If unsure, say N.
  1134. config BUILD_DOCSRC
  1135. bool "Build targets in Documentation/ tree"
  1136. depends on HEADERS_CHECK
  1137. help
  1138. This option attempts to build objects from the source files in the
  1139. kernel Documentation/ tree.
  1140. Say N if you are unsure.
  1141. config DYNAMIC_DEBUG
  1142. bool "Enable dynamic printk() support"
  1143. default n
  1144. depends on PRINTK
  1145. depends on DEBUG_FS
  1146. help
  1147. Compiles debug level messages into the kernel, which would not
  1148. otherwise be available at runtime. These messages can then be
  1149. enabled/disabled based on various levels of scope - per source file,
  1150. function, module, format string, and line number. This mechanism
  1151. implicitly compiles in all pr_debug() and dev_dbg() calls, which
  1152. enlarges the kernel text size by about 2%.
  1153. If a source file is compiled with DEBUG flag set, any
  1154. pr_debug() calls in it are enabled by default, but can be
  1155. disabled at runtime as below. Note that DEBUG flag is
  1156. turned on by many CONFIG_*DEBUG* options.
  1157. Usage:
  1158. Dynamic debugging is controlled via the 'dynamic_debug/control' file,
  1159. which is contained in the 'debugfs' filesystem. Thus, the debugfs
  1160. filesystem must first be mounted before making use of this feature.
  1161. We refer the control file as: <debugfs>/dynamic_debug/control. This
  1162. file contains a list of the debug statements that can be enabled. The
  1163. format for each line of the file is:
  1164. filename:lineno [module]function flags format
  1165. filename : source file of the debug statement
  1166. lineno : line number of the debug statement
  1167. module : module that contains the debug statement
  1168. function : function that contains the debug statement
  1169. flags : '=p' means the line is turned 'on' for printing
  1170. format : the format used for the debug statement
  1171. From a live system:
  1172. nullarbor:~ # cat <debugfs>/dynamic_debug/control
  1173. # filename:lineno [module]function flags format
  1174. fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
  1175. fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
  1176. fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
  1177. Example usage:
  1178. // enable the message at line 1603 of file svcsock.c
  1179. nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
  1180. <debugfs>/dynamic_debug/control
  1181. // enable all the messages in file svcsock.c
  1182. nullarbor:~ # echo -n 'file svcsock.c +p' >
  1183. <debugfs>/dynamic_debug/control
  1184. // enable all the messages in the NFS server module
  1185. nullarbor:~ # echo -n 'module nfsd +p' >
  1186. <debugfs>/dynamic_debug/control
  1187. // enable all 12 messages in the function svc_process()
  1188. nullarbor:~ # echo -n 'func svc_process +p' >
  1189. <debugfs>/dynamic_debug/control
  1190. // disable all 12 messages in the function svc_process()
  1191. nullarbor:~ # echo -n 'func svc_process -p' >
  1192. <debugfs>/dynamic_debug/control
  1193. See Documentation/dynamic-debug-howto.txt for additional information.
  1194. config DMA_API_DEBUG
  1195. bool "Enable debugging of DMA-API usage"
  1196. depends on HAVE_DMA_API_DEBUG
  1197. help
  1198. Enable this option to debug the use of the DMA API by device drivers.
  1199. With this option you will be able to detect common bugs in device
  1200. drivers like double-freeing of DMA mappings or freeing mappings that
  1201. were never allocated.
  1202. This option causes a performance degredation. Use only if you want
  1203. to debug device drivers. If unsure, say N.
  1204. config ATOMIC64_SELFTEST
  1205. bool "Perform an atomic64_t self-test at boot"
  1206. help
  1207. Enable this option to test the atomic64_t functions at boot.
  1208. If unsure, say N.
  1209. config ASYNC_RAID6_TEST
  1210. tristate "Self test for hardware accelerated raid6 recovery"
  1211. depends on ASYNC_RAID6_RECOV
  1212. select ASYNC_MEMCPY
  1213. ---help---
  1214. This is a one-shot self test that permutes through the
  1215. recovery of all the possible two disk failure scenarios for a
  1216. N-disk array. Recovery is performed with the asynchronous
  1217. raid6 recovery routines, and will optionally use an offload
  1218. engine if one is available.
  1219. If unsure, say N.
  1220. source "samples/Kconfig"
  1221. source "lib/Kconfig.kgdb"
  1222. source "lib/Kconfig.kmemcheck"
  1223. config TEST_KSTRTOX
  1224. tristate "Test kstrto*() family of functions at runtime"