Kconfig.debug 45 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 LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
  174. !HAVE_NMI_WATCHDOG
  175. config BOOTPARAM_HARDLOCKUP_PANIC
  176. bool "Panic (Reboot) On Hard Lockups"
  177. depends on LOCKUP_DETECTOR
  178. help
  179. Say Y here to enable the kernel to panic on "hard lockups",
  180. which are bugs that cause the kernel to loop in kernel
  181. mode with interrupts disabled for more than 10 seconds (configurable
  182. using the watchdog_thresh sysctl).
  183. Say N if unsure.
  184. config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
  185. int
  186. depends on LOCKUP_DETECTOR
  187. range 0 1
  188. default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
  189. default 1 if BOOTPARAM_HARDLOCKUP_PANIC
  190. config BOOTPARAM_SOFTLOCKUP_PANIC
  191. bool "Panic (Reboot) On Soft Lockups"
  192. depends on LOCKUP_DETECTOR
  193. help
  194. Say Y here to enable the kernel to panic on "soft lockups",
  195. which are bugs that cause the kernel to loop in kernel
  196. mode for more than 20 seconds (configurable using the watchdog_thresh
  197. sysctl), without giving other tasks a chance to run.
  198. The panic can be used in combination with panic_timeout,
  199. to cause the system to reboot automatically after a
  200. lockup has been detected. This feature is useful for
  201. high-availability systems that have uptime guarantees and
  202. where a lockup must be resolved ASAP.
  203. Say N if unsure.
  204. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  205. int
  206. depends on LOCKUP_DETECTOR
  207. range 0 1
  208. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  209. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  210. config DETECT_HUNG_TASK
  211. bool "Detect Hung Tasks"
  212. depends on DEBUG_KERNEL
  213. default LOCKUP_DETECTOR
  214. help
  215. Say Y here to enable the kernel to detect "hung tasks",
  216. which are bugs that cause the task to be stuck in
  217. uninterruptible "D" state indefinitiley.
  218. When a hung task is detected, the kernel will print the
  219. current stack trace (which you should report), but the
  220. task will stay in uninterruptible state. If lockdep is
  221. enabled then all held locks will also be reported. This
  222. feature has negligible overhead.
  223. config DEFAULT_HUNG_TASK_TIMEOUT
  224. int "Default timeout for hung task detection (in seconds)"
  225. depends on DETECT_HUNG_TASK
  226. default 120
  227. help
  228. This option controls the default timeout (in seconds) used
  229. to determine when a task has become non-responsive and should
  230. be considered hung.
  231. It can be adjusted at runtime via the kernel.hung_task_timeout_secs
  232. sysctl or by writing a value to
  233. /proc/sys/kernel/hung_task_timeout_secs.
  234. A timeout of 0 disables the check. The default is two minutes.
  235. Keeping the default should be fine in most cases.
  236. config BOOTPARAM_HUNG_TASK_PANIC
  237. bool "Panic (Reboot) On Hung Tasks"
  238. depends on DETECT_HUNG_TASK
  239. help
  240. Say Y here to enable the kernel to panic on "hung tasks",
  241. which are bugs that cause the kernel to leave a task stuck
  242. in uninterruptible "D" state.
  243. The panic can be used in combination with panic_timeout,
  244. to cause the system to reboot automatically after a
  245. hung task has been detected. This feature is useful for
  246. high-availability systems that have uptime guarantees and
  247. where a hung tasks must be resolved ASAP.
  248. Say N if unsure.
  249. config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  250. int
  251. depends on DETECT_HUNG_TASK
  252. range 0 1
  253. default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  254. default 1 if BOOTPARAM_HUNG_TASK_PANIC
  255. config SCHED_DEBUG
  256. bool "Collect scheduler debugging info"
  257. depends on DEBUG_KERNEL && PROC_FS
  258. default y
  259. help
  260. If you say Y here, the /proc/sched_debug file will be provided
  261. that can help debug the scheduler. The runtime overhead of this
  262. option is minimal.
  263. config SCHEDSTATS
  264. bool "Collect scheduler statistics"
  265. depends on DEBUG_KERNEL && PROC_FS
  266. help
  267. If you say Y here, additional code will be inserted into the
  268. scheduler and related routines to collect statistics about
  269. scheduler behavior and provide them in /proc/schedstat. These
  270. stats may be useful for both tuning and debugging the scheduler
  271. If you aren't debugging the scheduler or trying to tune a specific
  272. application, you can say N to avoid the very slight overhead
  273. this adds.
  274. config TIMER_STATS
  275. bool "Collect kernel timers statistics"
  276. depends on DEBUG_KERNEL && PROC_FS
  277. help
  278. If you say Y here, additional code will be inserted into the
  279. timer routines to collect statistics about kernel timers being
  280. reprogrammed. The statistics can be read from /proc/timer_stats.
  281. The statistics collection is started by writing 1 to /proc/timer_stats,
  282. writing 0 stops it. This feature is useful to collect information
  283. about timer usage patterns in kernel and userspace. This feature
  284. is lightweight if enabled in the kernel config but not activated
  285. (it defaults to deactivated on bootup and will only be activated
  286. if some application like powertop activates it explicitly).
  287. config DEBUG_OBJECTS
  288. bool "Debug object operations"
  289. depends on DEBUG_KERNEL
  290. help
  291. If you say Y here, additional code will be inserted into the
  292. kernel to track the life time of various objects and validate
  293. the operations on those objects.
  294. config DEBUG_OBJECTS_SELFTEST
  295. bool "Debug objects selftest"
  296. depends on DEBUG_OBJECTS
  297. help
  298. This enables the selftest of the object debug code.
  299. config DEBUG_OBJECTS_FREE
  300. bool "Debug objects in freed memory"
  301. depends on DEBUG_OBJECTS
  302. help
  303. This enables checks whether a k/v free operation frees an area
  304. which contains an object which has not been deactivated
  305. properly. This can make kmalloc/kfree-intensive workloads
  306. much slower.
  307. config DEBUG_OBJECTS_TIMERS
  308. bool "Debug timer objects"
  309. depends on DEBUG_OBJECTS
  310. help
  311. If you say Y here, additional code will be inserted into the
  312. timer routines to track the life time of timer objects and
  313. validate the timer operations.
  314. config DEBUG_OBJECTS_WORK
  315. bool "Debug work objects"
  316. depends on DEBUG_OBJECTS
  317. help
  318. If you say Y here, additional code will be inserted into the
  319. work queue routines to track the life time of work objects and
  320. validate the work operations.
  321. config DEBUG_OBJECTS_RCU_HEAD
  322. bool "Debug RCU callbacks objects"
  323. depends on DEBUG_OBJECTS
  324. help
  325. Enable this to turn on debugging of RCU list heads (call_rcu() usage).
  326. config DEBUG_OBJECTS_PERCPU_COUNTER
  327. bool "Debug percpu counter objects"
  328. depends on DEBUG_OBJECTS
  329. help
  330. If you say Y here, additional code will be inserted into the
  331. percpu counter routines to track the life time of percpu counter
  332. objects and validate the percpu counter operations.
  333. config DEBUG_OBJECTS_ENABLE_DEFAULT
  334. int "debug_objects bootup default value (0-1)"
  335. range 0 1
  336. default "1"
  337. depends on DEBUG_OBJECTS
  338. help
  339. Debug objects boot parameter default value
  340. config DEBUG_SLAB
  341. bool "Debug slab memory allocations"
  342. depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
  343. help
  344. Say Y here to have the kernel do limited verification on memory
  345. allocation as well as poisoning memory on free to catch use of freed
  346. memory. This can make kmalloc/kfree-intensive workloads much slower.
  347. config DEBUG_SLAB_LEAK
  348. bool "Memory leak debugging"
  349. depends on DEBUG_SLAB
  350. config SLUB_DEBUG_ON
  351. bool "SLUB debugging on by default"
  352. depends on SLUB && SLUB_DEBUG && !KMEMCHECK
  353. default n
  354. help
  355. Boot with debugging on by default. SLUB boots by default with
  356. the runtime debug capabilities switched off. Enabling this is
  357. equivalent to specifying the "slub_debug" parameter on boot.
  358. There is no support for more fine grained debug control like
  359. possible with slub_debug=xxx. SLUB debugging may be switched
  360. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  361. "slub_debug=-".
  362. config SLUB_STATS
  363. default n
  364. bool "Enable SLUB performance statistics"
  365. depends on SLUB && SYSFS
  366. help
  367. SLUB statistics are useful to debug SLUBs allocation behavior in
  368. order find ways to optimize the allocator. This should never be
  369. enabled for production use since keeping statistics slows down
  370. the allocator by a few percentage points. The slabinfo command
  371. supports the determination of the most active slabs to figure
  372. out which slabs are relevant to a particular load.
  373. Try running: slabinfo -DA
  374. config DEBUG_KMEMLEAK
  375. bool "Kernel memory leak detector"
  376. depends on DEBUG_KERNEL && EXPERIMENTAL && \
  377. (X86 || ARM || PPC || MIPS || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
  378. select DEBUG_FS
  379. select STACKTRACE if STACKTRACE_SUPPORT
  380. select KALLSYMS
  381. select CRC32
  382. help
  383. Say Y here if you want to enable the memory leak
  384. detector. The memory allocation/freeing is traced in a way
  385. similar to the Boehm's conservative garbage collector, the
  386. difference being that the orphan objects are not freed but
  387. only shown in /sys/kernel/debug/kmemleak. Enabling this
  388. feature will introduce an overhead to memory
  389. allocations. See Documentation/kmemleak.txt for more
  390. details.
  391. Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  392. of finding leaks due to the slab objects poisoning.
  393. In order to access the kmemleak file, debugfs needs to be
  394. mounted (usually at /sys/kernel/debug).
  395. config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
  396. int "Maximum kmemleak early log entries"
  397. depends on DEBUG_KMEMLEAK
  398. range 200 40000
  399. default 400
  400. help
  401. Kmemleak must track all the memory allocations to avoid
  402. reporting false positives. Since memory may be allocated or
  403. freed before kmemleak is initialised, an early log buffer is
  404. used to store these actions. If kmemleak reports "early log
  405. buffer exceeded", please increase this value.
  406. config DEBUG_KMEMLEAK_TEST
  407. tristate "Simple test for the kernel memory leak detector"
  408. depends on DEBUG_KMEMLEAK && m
  409. help
  410. This option enables a module that explicitly leaks memory.
  411. If unsure, say N.
  412. config DEBUG_KMEMLEAK_DEFAULT_OFF
  413. bool "Default kmemleak to off"
  414. depends on DEBUG_KMEMLEAK
  415. help
  416. Say Y here to disable kmemleak by default. It can then be enabled
  417. on the command line via kmemleak=on.
  418. config DEBUG_PREEMPT
  419. bool "Debug preemptible kernel"
  420. depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
  421. default y
  422. help
  423. If you say Y here then the kernel will use a debug variant of the
  424. commonly used smp_processor_id() function and will print warnings
  425. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  426. will detect preemption count underflows.
  427. config DEBUG_RT_MUTEXES
  428. bool "RT Mutex debugging, deadlock detection"
  429. depends on DEBUG_KERNEL && RT_MUTEXES
  430. help
  431. This allows rt mutex semantics violations and rt mutex related
  432. deadlocks (lockups) to be detected and reported automatically.
  433. config DEBUG_PI_LIST
  434. bool
  435. default y
  436. depends on DEBUG_RT_MUTEXES
  437. config RT_MUTEX_TESTER
  438. bool "Built-in scriptable tester for rt-mutexes"
  439. depends on DEBUG_KERNEL && RT_MUTEXES
  440. help
  441. This option enables a rt-mutex tester.
  442. config DEBUG_SPINLOCK
  443. bool "Spinlock and rw-lock debugging: basic checks"
  444. depends on DEBUG_KERNEL
  445. select UNINLINE_SPIN_UNLOCK
  446. help
  447. Say Y here and build SMP to catch missing spinlock initialization
  448. and certain other kinds of spinlock errors commonly made. This is
  449. best used in conjunction with the NMI watchdog so that spinlock
  450. deadlocks are also debuggable.
  451. config DEBUG_MUTEXES
  452. bool "Mutex debugging: basic checks"
  453. depends on DEBUG_KERNEL
  454. help
  455. This feature allows mutex semantics violations to be detected and
  456. reported.
  457. config DEBUG_LOCK_ALLOC
  458. bool "Lock debugging: detect incorrect freeing of live locks"
  459. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  460. select DEBUG_SPINLOCK
  461. select DEBUG_MUTEXES
  462. select LOCKDEP
  463. help
  464. This feature will check whether any held lock (spinlock, rwlock,
  465. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  466. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  467. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  468. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  469. held during task exit.
  470. config PROVE_LOCKING
  471. bool "Lock debugging: prove locking correctness"
  472. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  473. select LOCKDEP
  474. select DEBUG_SPINLOCK
  475. select DEBUG_MUTEXES
  476. select DEBUG_LOCK_ALLOC
  477. select TRACE_IRQFLAGS
  478. default n
  479. help
  480. This feature enables the kernel to prove that all locking
  481. that occurs in the kernel runtime is mathematically
  482. correct: that under no circumstance could an arbitrary (and
  483. not yet triggered) combination of observed locking
  484. sequences (on an arbitrary number of CPUs, running an
  485. arbitrary number of tasks and interrupt contexts) cause a
  486. deadlock.
  487. In short, this feature enables the kernel to report locking
  488. related deadlocks before they actually occur.
  489. The proof does not depend on how hard and complex a
  490. deadlock scenario would be to trigger: how many
  491. participant CPUs, tasks and irq-contexts would be needed
  492. for it to trigger. The proof also does not depend on
  493. timing: if a race and a resulting deadlock is possible
  494. theoretically (no matter how unlikely the race scenario
  495. is), it will be proven so and will immediately be
  496. reported by the kernel (once the event is observed that
  497. makes the deadlock theoretically possible).
  498. If a deadlock is impossible (i.e. the locking rules, as
  499. observed by the kernel, are mathematically correct), the
  500. kernel reports nothing.
  501. NOTE: this feature can also be enabled for rwlocks, mutexes
  502. and rwsems - in which case all dependencies between these
  503. different locking variants are observed and mapped too, and
  504. the proof of observed correctness is also maintained for an
  505. arbitrary combination of these separate locking variants.
  506. For more details, see Documentation/lockdep-design.txt.
  507. config PROVE_RCU
  508. bool "RCU debugging: prove RCU correctness"
  509. depends on PROVE_LOCKING
  510. default n
  511. help
  512. This feature enables lockdep extensions that check for correct
  513. use of RCU APIs. This is currently under development. Say Y
  514. if you want to debug RCU usage or help work on the PROVE_RCU
  515. feature.
  516. Say N if you are unsure.
  517. config PROVE_RCU_REPEATEDLY
  518. bool "RCU debugging: don't disable PROVE_RCU on first splat"
  519. depends on PROVE_RCU
  520. default n
  521. help
  522. By itself, PROVE_RCU will disable checking upon issuing the
  523. first warning (or "splat"). This feature prevents such
  524. disabling, allowing multiple RCU-lockdep warnings to be printed
  525. on a single reboot.
  526. Say Y to allow multiple RCU-lockdep warnings per boot.
  527. Say N if you are unsure.
  528. config SPARSE_RCU_POINTER
  529. bool "RCU debugging: sparse-based checks for pointer usage"
  530. default n
  531. help
  532. This feature enables the __rcu sparse annotation for
  533. RCU-protected pointers. This annotation will cause sparse
  534. to flag any non-RCU used of annotated pointers. This can be
  535. helpful when debugging RCU usage. Please note that this feature
  536. is not intended to enforce code cleanliness; it is instead merely
  537. a debugging aid.
  538. Say Y to make sparse flag questionable use of RCU-protected pointers
  539. Say N if you are unsure.
  540. config LOCKDEP
  541. bool
  542. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  543. select STACKTRACE
  544. select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
  545. select KALLSYMS
  546. select KALLSYMS_ALL
  547. config LOCK_STAT
  548. bool "Lock usage statistics"
  549. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  550. select LOCKDEP
  551. select DEBUG_SPINLOCK
  552. select DEBUG_MUTEXES
  553. select DEBUG_LOCK_ALLOC
  554. default n
  555. help
  556. This feature enables tracking lock contention points
  557. For more details, see Documentation/lockstat.txt
  558. This also enables lock events required by "perf lock",
  559. subcommand of perf.
  560. If you want to use "perf lock", you also need to turn on
  561. CONFIG_EVENT_TRACING.
  562. CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
  563. (CONFIG_LOCKDEP defines "acquire" and "release" events.)
  564. config DEBUG_LOCKDEP
  565. bool "Lock dependency engine debugging"
  566. depends on DEBUG_KERNEL && LOCKDEP
  567. help
  568. If you say Y here, the lock dependency engine will do
  569. additional runtime checks to debug itself, at the price
  570. of more runtime overhead.
  571. config TRACE_IRQFLAGS
  572. bool
  573. help
  574. Enables hooks to interrupt enabling and disabling for
  575. either tracing or lock debugging.
  576. config DEBUG_ATOMIC_SLEEP
  577. bool "Sleep inside atomic section checking"
  578. select PREEMPT_COUNT
  579. depends on DEBUG_KERNEL
  580. help
  581. If you say Y here, various routines which may sleep will become very
  582. noisy if they are called inside atomic sections: when a spinlock is
  583. held, inside an rcu read side critical section, inside preempt disabled
  584. sections, inside an interrupt, etc...
  585. config DEBUG_LOCKING_API_SELFTESTS
  586. bool "Locking API boot-time self-tests"
  587. depends on DEBUG_KERNEL
  588. help
  589. Say Y here if you want the kernel to run a short self-test during
  590. bootup. The self-test checks whether common types of locking bugs
  591. are detected by debugging mechanisms or not. (if you disable
  592. lock debugging then those bugs wont be detected of course.)
  593. The following locking APIs are covered: spinlocks, rwlocks,
  594. mutexes and rwsems.
  595. config STACKTRACE
  596. bool
  597. depends on STACKTRACE_SUPPORT
  598. config DEBUG_STACK_USAGE
  599. bool "Stack utilization instrumentation"
  600. depends on DEBUG_KERNEL && !IA64 && !PARISC
  601. help
  602. Enables the display of the minimum amount of free stack which each
  603. task has ever had available in the sysrq-T and sysrq-P debug output.
  604. This option will slow down process creation somewhat.
  605. config DEBUG_KOBJECT
  606. bool "kobject debugging"
  607. depends on DEBUG_KERNEL
  608. help
  609. If you say Y here, some extra kobject debugging messages will be sent
  610. to the syslog.
  611. config DEBUG_HIGHMEM
  612. bool "Highmem debugging"
  613. depends on DEBUG_KERNEL && HIGHMEM
  614. help
  615. This options enables addition error checking for high memory systems.
  616. Disable for production systems.
  617. config DEBUG_BUGVERBOSE
  618. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
  619. depends on BUG
  620. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  621. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 || TILE
  622. default y
  623. help
  624. Say Y here to make BUG() panics output the file name and line number
  625. of the BUG call as well as the EIP and oops trace. This aids
  626. debugging but costs about 70-100K of memory.
  627. config DEBUG_INFO
  628. bool "Compile the kernel with debug info"
  629. depends on DEBUG_KERNEL
  630. help
  631. If you say Y here the resulting kernel image will include
  632. debugging info resulting in a larger kernel image.
  633. This adds debug symbols to the kernel and modules (gcc -g), and
  634. is needed if you intend to use kernel crashdump or binary object
  635. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  636. Say Y here only if you plan to debug the kernel.
  637. If unsure, say N.
  638. config DEBUG_INFO_REDUCED
  639. bool "Reduce debugging information"
  640. depends on DEBUG_INFO
  641. help
  642. If you say Y here gcc is instructed to generate less debugging
  643. information for structure types. This means that tools that
  644. need full debugging information (like kgdb or systemtap) won't
  645. be happy. But if you merely need debugging information to
  646. resolve line numbers there is no loss. Advantage is that
  647. build directory object sizes shrink dramatically over a full
  648. DEBUG_INFO build and compile times are reduced too.
  649. Only works with newer gcc versions.
  650. config DEBUG_VM
  651. bool "Debug VM"
  652. depends on DEBUG_KERNEL
  653. help
  654. Enable this to turn on extended checks in the virtual-memory system
  655. that may impact performance.
  656. If unsure, say N.
  657. config DEBUG_VIRTUAL
  658. bool "Debug VM translations"
  659. depends on DEBUG_KERNEL && X86
  660. help
  661. Enable some costly sanity checks in virtual to page code. This can
  662. catch mistakes with virt_to_page() and friends.
  663. If unsure, say N.
  664. config DEBUG_NOMMU_REGIONS
  665. bool "Debug the global anon/private NOMMU mapping region tree"
  666. depends on DEBUG_KERNEL && !MMU
  667. help
  668. This option causes the global tree of anonymous and private mapping
  669. regions to be regularly checked for invalid topology.
  670. config DEBUG_WRITECOUNT
  671. bool "Debug filesystem writers count"
  672. depends on DEBUG_KERNEL
  673. help
  674. Enable this to catch wrong use of the writers count in struct
  675. vfsmount. This will increase the size of each file struct by
  676. 32 bits.
  677. If unsure, say N.
  678. config DEBUG_MEMORY_INIT
  679. bool "Debug memory initialisation" if EXPERT
  680. default !EXPERT
  681. help
  682. Enable this for additional checks during memory initialisation.
  683. The sanity checks verify aspects of the VM such as the memory model
  684. and other information provided by the architecture. Verbose
  685. information will be printed at KERN_DEBUG loglevel depending
  686. on the mminit_loglevel= command-line option.
  687. If unsure, say Y
  688. config DEBUG_LIST
  689. bool "Debug linked list manipulation"
  690. depends on DEBUG_KERNEL
  691. help
  692. Enable this to turn on extended checks in the linked-list
  693. walking routines.
  694. If unsure, say N.
  695. config TEST_LIST_SORT
  696. bool "Linked list sorting test"
  697. depends on DEBUG_KERNEL
  698. help
  699. Enable this to turn on 'list_sort()' function test. This test is
  700. executed only once during system boot, so affects only boot time.
  701. If unsure, say N.
  702. config DEBUG_SG
  703. bool "Debug SG table operations"
  704. depends on DEBUG_KERNEL
  705. help
  706. Enable this to turn on checks on scatter-gather tables. This can
  707. help find problems with drivers that do not properly initialize
  708. their sg tables.
  709. If unsure, say N.
  710. config DEBUG_NOTIFIERS
  711. bool "Debug notifier call chains"
  712. depends on DEBUG_KERNEL
  713. help
  714. Enable this to turn on sanity checking for notifier call chains.
  715. This is most useful for kernel developers to make sure that
  716. modules properly unregister themselves from notifier chains.
  717. This is a relatively cheap check but if you care about maximum
  718. performance, say N.
  719. config DEBUG_CREDENTIALS
  720. bool "Debug credential management"
  721. depends on DEBUG_KERNEL
  722. help
  723. Enable this to turn on some debug checking for credential
  724. management. The additional code keeps track of the number of
  725. pointers from task_structs to any given cred struct, and checks to
  726. see that this number never exceeds the usage count of the cred
  727. struct.
  728. Furthermore, if SELinux is enabled, this also checks that the
  729. security pointer in the cred struct is never seen to be invalid.
  730. If unsure, say N.
  731. #
  732. # Select this config option from the architecture Kconfig, if it
  733. # is preferred to always offer frame pointers as a config
  734. # option on the architecture (regardless of KERNEL_DEBUG):
  735. #
  736. config ARCH_WANT_FRAME_POINTERS
  737. bool
  738. help
  739. config FRAME_POINTER
  740. bool "Compile the kernel with frame pointers"
  741. depends on DEBUG_KERNEL && \
  742. (CRIS || M68K || FRV || UML || \
  743. AVR32 || SUPERH || BLACKFIN || MN10300) || \
  744. ARCH_WANT_FRAME_POINTERS
  745. default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
  746. help
  747. If you say Y here the resulting kernel image will be slightly
  748. larger and slower, but it gives very useful debugging information
  749. in case of kernel bugs. (precise oopses/stacktraces/warnings)
  750. config BOOT_PRINTK_DELAY
  751. bool "Delay each boot printk message by N milliseconds"
  752. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  753. help
  754. This build option allows you to read kernel boot messages
  755. by inserting a short delay after each one. The delay is
  756. specified in milliseconds on the kernel command line,
  757. using "boot_delay=N".
  758. It is likely that you would also need to use "lpj=M" to preset
  759. the "loops per jiffie" value.
  760. See a previous boot log for the "lpj" value to use for your
  761. system, and then set "lpj=M" before setting "boot_delay=N".
  762. NOTE: Using this option may adversely affect SMP systems.
  763. I.e., processors other than the first one may not boot up.
  764. BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
  765. what it believes to be lockup conditions.
  766. config RCU_TORTURE_TEST
  767. tristate "torture tests for RCU"
  768. depends on DEBUG_KERNEL
  769. default n
  770. help
  771. This option provides a kernel module that runs torture tests
  772. on the RCU infrastructure. The kernel module may be built
  773. after the fact on the running kernel to be tested, if desired.
  774. Say Y here if you want RCU torture tests to be built into
  775. the kernel.
  776. Say M if you want the RCU torture tests to build as a module.
  777. Say N if you are unsure.
  778. config RCU_TORTURE_TEST_RUNNABLE
  779. bool "torture tests for RCU runnable by default"
  780. depends on RCU_TORTURE_TEST = y
  781. default n
  782. help
  783. This option provides a way to build the RCU torture tests
  784. directly into the kernel without them starting up at boot
  785. time. You can use /proc/sys/kernel/rcutorture_runnable
  786. to manually override this setting. This /proc file is
  787. available only when the RCU torture tests have been built
  788. into the kernel.
  789. Say Y here if you want the RCU torture tests to start during
  790. boot (you probably don't).
  791. Say N here if you want the RCU torture tests to start only
  792. after being manually enabled via /proc.
  793. config RCU_CPU_STALL_TIMEOUT
  794. int "RCU CPU stall timeout in seconds"
  795. depends on TREE_RCU || TREE_PREEMPT_RCU
  796. range 3 300
  797. default 60
  798. help
  799. If a given RCU grace period extends more than the specified
  800. number of seconds, a CPU stall warning is printed. If the
  801. RCU grace period persists, additional CPU stall warnings are
  802. printed at more widely spaced intervals.
  803. config RCU_CPU_STALL_VERBOSE
  804. bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
  805. depends on TREE_PREEMPT_RCU
  806. default y
  807. help
  808. This option causes RCU to printk detailed per-task information
  809. for any tasks that are stalling the current RCU grace period.
  810. Say N if you are unsure.
  811. Say Y if you want to enable such checks.
  812. config RCU_CPU_STALL_INFO
  813. bool "Print additional diagnostics on RCU CPU stall"
  814. depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
  815. default n
  816. help
  817. For each stalled CPU that is aware of the current RCU grace
  818. period, print out additional per-CPU diagnostic information
  819. regarding scheduling-clock ticks, idle state, and,
  820. for RCU_FAST_NO_HZ kernels, idle-entry state.
  821. Say N if you are unsure.
  822. Say Y if you want to enable such diagnostics.
  823. config RCU_TRACE
  824. bool "Enable tracing for RCU"
  825. depends on DEBUG_KERNEL
  826. help
  827. This option provides tracing in RCU which presents stats
  828. in debugfs for debugging RCU implementation.
  829. Say Y here if you want to enable RCU tracing
  830. Say N if you are unsure.
  831. config KPROBES_SANITY_TEST
  832. bool "Kprobes sanity tests"
  833. depends on DEBUG_KERNEL
  834. depends on KPROBES
  835. default n
  836. help
  837. This option provides for testing basic kprobes functionality on
  838. boot. A sample kprobe, jprobe and kretprobe are inserted and
  839. verified for functionality.
  840. Say N if you are unsure.
  841. config BACKTRACE_SELF_TEST
  842. tristate "Self test for the backtrace code"
  843. depends on DEBUG_KERNEL
  844. default n
  845. help
  846. This option provides a kernel module that can be used to test
  847. the kernel stack backtrace code. This option is not useful
  848. for distributions or general kernels, but only for kernel
  849. developers working on architecture code.
  850. Note that if you want to also test saved backtraces, you will
  851. have to enable STACKTRACE as well.
  852. Say N if you are unsure.
  853. config DEBUG_BLOCK_EXT_DEVT
  854. bool "Force extended block device numbers and spread them"
  855. depends on DEBUG_KERNEL
  856. depends on BLOCK
  857. default n
  858. help
  859. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  860. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  861. YOU ARE DOING. Distros, please enable this and fix whatever
  862. is broken.
  863. Conventionally, block device numbers are allocated from
  864. predetermined contiguous area. However, extended block area
  865. may introduce non-contiguous block device numbers. This
  866. option forces most block device numbers to be allocated from
  867. the extended space and spreads them to discover kernel or
  868. userland code paths which assume predetermined contiguous
  869. device number allocation.
  870. Note that turning on this debug option shuffles all the
  871. device numbers for all IDE and SCSI devices including libata
  872. ones, so root partition specified using device number
  873. directly (via rdev or root=MAJ:MIN) won't work anymore.
  874. Textual device names (root=/dev/sdXn) will continue to work.
  875. Say N if you are unsure.
  876. config DEBUG_FORCE_WEAK_PER_CPU
  877. bool "Force weak per-cpu definitions"
  878. depends on DEBUG_KERNEL
  879. help
  880. s390 and alpha require percpu variables in modules to be
  881. defined weak to work around addressing range issue which
  882. puts the following two restrictions on percpu variable
  883. definitions.
  884. 1. percpu symbols must be unique whether static or not
  885. 2. percpu variables can't be defined inside a function
  886. To ensure that generic code follows the above rules, this
  887. option forces all percpu variables to be defined as weak.
  888. config DEBUG_PER_CPU_MAPS
  889. bool "Debug access to per_cpu maps"
  890. depends on DEBUG_KERNEL
  891. depends on SMP
  892. help
  893. Say Y to verify that the per_cpu map being accessed has
  894. been set up. This adds a fair amount of code to kernel memory
  895. and decreases performance.
  896. Say N if unsure.
  897. config LKDTM
  898. tristate "Linux Kernel Dump Test Tool Module"
  899. depends on DEBUG_FS
  900. depends on BLOCK
  901. default n
  902. help
  903. This module enables testing of the different dumping mechanisms by
  904. inducing system failures at predefined crash points.
  905. If you don't need it: say N
  906. Choose M here to compile this code as a module. The module will be
  907. called lkdtm.
  908. Documentation on how to use the module can be found in
  909. Documentation/fault-injection/provoke-crashes.txt
  910. config CPU_NOTIFIER_ERROR_INJECT
  911. tristate "CPU notifier error injection module"
  912. depends on HOTPLUG_CPU && DEBUG_KERNEL
  913. help
  914. This option provides a kernel module that can be used to test
  915. the error handling of the cpu notifiers
  916. To compile this code as a module, choose M here: the module will
  917. be called cpu-notifier-error-inject.
  918. If unsure, say N.
  919. config FAULT_INJECTION
  920. bool "Fault-injection framework"
  921. depends on DEBUG_KERNEL
  922. help
  923. Provide fault-injection framework.
  924. For more details, see Documentation/fault-injection/.
  925. config FAILSLAB
  926. bool "Fault-injection capability for kmalloc"
  927. depends on FAULT_INJECTION
  928. depends on SLAB || SLUB
  929. help
  930. Provide fault-injection capability for kmalloc.
  931. config FAIL_PAGE_ALLOC
  932. bool "Fault-injection capabilitiy for alloc_pages()"
  933. depends on FAULT_INJECTION
  934. help
  935. Provide fault-injection capability for alloc_pages().
  936. config FAIL_MAKE_REQUEST
  937. bool "Fault-injection capability for disk IO"
  938. depends on FAULT_INJECTION && BLOCK
  939. help
  940. Provide fault-injection capability for disk IO.
  941. config FAIL_IO_TIMEOUT
  942. bool "Fault-injection capability for faking disk interrupts"
  943. depends on FAULT_INJECTION && BLOCK
  944. help
  945. Provide fault-injection capability on end IO handling. This
  946. will make the block layer "forget" an interrupt as configured,
  947. thus exercising the error handling.
  948. Only works with drivers that use the generic timeout handling,
  949. for others it wont do anything.
  950. config FAIL_MMC_REQUEST
  951. bool "Fault-injection capability for MMC IO"
  952. select DEBUG_FS
  953. depends on FAULT_INJECTION && MMC
  954. help
  955. Provide fault-injection capability for MMC IO.
  956. This will make the mmc core return data errors. This is
  957. useful to test the error handling in the mmc block device
  958. and to test how the mmc host driver handles retries from
  959. the block device.
  960. config FAULT_INJECTION_DEBUG_FS
  961. bool "Debugfs entries for fault-injection capabilities"
  962. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  963. help
  964. Enable configuration of fault-injection capabilities via debugfs.
  965. config FAULT_INJECTION_STACKTRACE_FILTER
  966. bool "stacktrace filter for fault-injection capabilities"
  967. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  968. depends on !X86_64
  969. select STACKTRACE
  970. select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  971. help
  972. Provide stacktrace filter for fault-injection capabilities
  973. config LATENCYTOP
  974. bool "Latency measuring infrastructure"
  975. depends on HAVE_LATENCYTOP_SUPPORT
  976. depends on DEBUG_KERNEL
  977. depends on STACKTRACE_SUPPORT
  978. depends on PROC_FS
  979. select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  980. select KALLSYMS
  981. select KALLSYMS_ALL
  982. select STACKTRACE
  983. select SCHEDSTATS
  984. select SCHED_DEBUG
  985. help
  986. Enable this option if you want to use the LatencyTOP tool
  987. to find out which userspace is blocking on what kernel operations.
  988. source mm/Kconfig.debug
  989. source kernel/trace/Kconfig
  990. config PROVIDE_OHCI1394_DMA_INIT
  991. bool "Remote debugging over FireWire early on boot"
  992. depends on PCI && X86
  993. help
  994. If you want to debug problems which hang or crash the kernel early
  995. on boot and the crashing machine has a FireWire port, you can use
  996. this feature to remotely access the memory of the crashed machine
  997. over FireWire. This employs remote DMA as part of the OHCI1394
  998. specification which is now the standard for FireWire controllers.
  999. With remote DMA, you can monitor the printk buffer remotely using
  1000. firescope and access all memory below 4GB using fireproxy from gdb.
  1001. Even controlling a kernel debugger is possible using remote DMA.
  1002. Usage:
  1003. If ohci1394_dma=early is used as boot parameter, it will initialize
  1004. all OHCI1394 controllers which are found in the PCI config space.
  1005. As all changes to the FireWire bus such as enabling and disabling
  1006. devices cause a bus reset and thereby disable remote DMA for all
  1007. devices, be sure to have the cable plugged and FireWire enabled on
  1008. the debugging host before booting the debug target for debugging.
  1009. This code (~1k) is freed after boot. By then, the firewire stack
  1010. in charge of the OHCI-1394 controllers should be used instead.
  1011. See Documentation/debugging-via-ohci1394.txt for more information.
  1012. config FIREWIRE_OHCI_REMOTE_DMA
  1013. bool "Remote debugging over FireWire with firewire-ohci"
  1014. depends on FIREWIRE_OHCI
  1015. help
  1016. This option lets you use the FireWire bus for remote debugging
  1017. with help of the firewire-ohci driver. It enables unfiltered
  1018. remote DMA in firewire-ohci.
  1019. See Documentation/debugging-via-ohci1394.txt for more information.
  1020. If unsure, say N.
  1021. config BUILD_DOCSRC
  1022. bool "Build targets in Documentation/ tree"
  1023. depends on HEADERS_CHECK
  1024. help
  1025. This option attempts to build objects from the source files in the
  1026. kernel Documentation/ tree.
  1027. Say N if you are unsure.
  1028. config DYNAMIC_DEBUG
  1029. bool "Enable dynamic printk() support"
  1030. default n
  1031. depends on PRINTK
  1032. depends on DEBUG_FS
  1033. help
  1034. Compiles debug level messages into the kernel, which would not
  1035. otherwise be available at runtime. These messages can then be
  1036. enabled/disabled based on various levels of scope - per source file,
  1037. function, module, format string, and line number. This mechanism
  1038. implicitly compiles in all pr_debug() and dev_dbg() calls, which
  1039. enlarges the kernel text size by about 2%.
  1040. If a source file is compiled with DEBUG flag set, any
  1041. pr_debug() calls in it are enabled by default, but can be
  1042. disabled at runtime as below. Note that DEBUG flag is
  1043. turned on by many CONFIG_*DEBUG* options.
  1044. Usage:
  1045. Dynamic debugging is controlled via the 'dynamic_debug/control' file,
  1046. which is contained in the 'debugfs' filesystem. Thus, the debugfs
  1047. filesystem must first be mounted before making use of this feature.
  1048. We refer the control file as: <debugfs>/dynamic_debug/control. This
  1049. file contains a list of the debug statements that can be enabled. The
  1050. format for each line of the file is:
  1051. filename:lineno [module]function flags format
  1052. filename : source file of the debug statement
  1053. lineno : line number of the debug statement
  1054. module : module that contains the debug statement
  1055. function : function that contains the debug statement
  1056. flags : '=p' means the line is turned 'on' for printing
  1057. format : the format used for the debug statement
  1058. From a live system:
  1059. nullarbor:~ # cat <debugfs>/dynamic_debug/control
  1060. # filename:lineno [module]function flags format
  1061. fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
  1062. fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
  1063. fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
  1064. Example usage:
  1065. // enable the message at line 1603 of file svcsock.c
  1066. nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
  1067. <debugfs>/dynamic_debug/control
  1068. // enable all the messages in file svcsock.c
  1069. nullarbor:~ # echo -n 'file svcsock.c +p' >
  1070. <debugfs>/dynamic_debug/control
  1071. // enable all the messages in the NFS server module
  1072. nullarbor:~ # echo -n 'module nfsd +p' >
  1073. <debugfs>/dynamic_debug/control
  1074. // enable all 12 messages in the function svc_process()
  1075. nullarbor:~ # echo -n 'func svc_process +p' >
  1076. <debugfs>/dynamic_debug/control
  1077. // disable all 12 messages in the function svc_process()
  1078. nullarbor:~ # echo -n 'func svc_process -p' >
  1079. <debugfs>/dynamic_debug/control
  1080. See Documentation/dynamic-debug-howto.txt for additional information.
  1081. config DMA_API_DEBUG
  1082. bool "Enable debugging of DMA-API usage"
  1083. depends on HAVE_DMA_API_DEBUG
  1084. help
  1085. Enable this option to debug the use of the DMA API by device drivers.
  1086. With this option you will be able to detect common bugs in device
  1087. drivers like double-freeing of DMA mappings or freeing mappings that
  1088. were never allocated.
  1089. This option causes a performance degredation. Use only if you want
  1090. to debug device drivers. If unsure, say N.
  1091. config ATOMIC64_SELFTEST
  1092. bool "Perform an atomic64_t self-test at boot"
  1093. help
  1094. Enable this option to test the atomic64_t functions at boot.
  1095. If unsure, say N.
  1096. config ASYNC_RAID6_TEST
  1097. tristate "Self test for hardware accelerated raid6 recovery"
  1098. depends on ASYNC_RAID6_RECOV
  1099. select ASYNC_MEMCPY
  1100. ---help---
  1101. This is a one-shot self test that permutes through the
  1102. recovery of all the possible two disk failure scenarios for a
  1103. N-disk array. Recovery is performed with the asynchronous
  1104. raid6 recovery routines, and will optionally use an offload
  1105. engine if one is available.
  1106. If unsure, say N.
  1107. source "samples/Kconfig"
  1108. source "lib/Kconfig.kgdb"
  1109. source "lib/Kconfig.kmemcheck"
  1110. config TEST_KSTRTOX
  1111. tristate "Test kstrto*() family of functions at runtime"