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 timing information to be
  6. included in printk output. This allows you to measure
  7. the interval between kernel operations, including bootup
  8. operations. This is useful for identifying long delays
  9. in kernel startup. Or add printk.time=1 at boot-time.
  10. See Documentation/kernel-parameters.txt
  11. config DEFAULT_MESSAGE_LOGLEVEL
  12. int "Default message log level (1-7)"
  13. range 1 7
  14. default "4"
  15. help
  16. Default log level for printk statements with no specified priority.
  17. This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
  18. that are auditing their logs closely may want to set it to a lower
  19. priority.
  20. config ENABLE_WARN_DEPRECATED
  21. bool "Enable __deprecated logic"
  22. default y
  23. help
  24. Enable the __deprecated logic in the kernel build.
  25. Disable this to suppress the "warning: 'foo' is deprecated
  26. (declared at kernel/power/somefile.c:1234)" messages.
  27. config ENABLE_MUST_CHECK
  28. bool "Enable __must_check logic"
  29. default y
  30. help
  31. Enable the __must_check logic in the kernel build. Disable this to
  32. suppress the "warning: ignoring return value of 'foo', declared with
  33. attribute warn_unused_result" messages.
  34. config FRAME_WARN
  35. int "Warn for stack frames larger than (needs gcc 4.4)"
  36. range 0 8192
  37. default 1024 if !64BIT
  38. default 2048 if 64BIT
  39. help
  40. Tell gcc to warn at build time for stack frames larger than this.
  41. Setting this too low will cause a lot of warnings.
  42. Setting it to 0 disables the warning.
  43. Requires gcc 4.4
  44. config MAGIC_SYSRQ
  45. bool "Magic SysRq key"
  46. depends on !UML
  47. help
  48. If you say Y here, you will have some control over the system even
  49. if the system crashes for example during kernel debugging (e.g., you
  50. will be able to flush the buffer cache to disk, reboot the system
  51. immediately or dump some status information). This is accomplished
  52. by pressing various keys while holding SysRq (Alt+PrintScreen). It
  53. also works on a serial console (on PC hardware at least), if you
  54. send a BREAK and then within 5 seconds a command keypress. The
  55. keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
  56. unless you really know what this hack does.
  57. config STRIP_ASM_SYMS
  58. bool "Strip assembler-generated symbols during link"
  59. default n
  60. help
  61. Strip internal assembler-generated symbols during a link (symbols
  62. that look like '.Lxxx') so they don't pollute the output of
  63. get_wchan() and suchlike.
  64. config UNUSED_SYMBOLS
  65. bool "Enable unused/obsolete exported symbols"
  66. default y if X86
  67. help
  68. Unused but exported symbols make the kernel needlessly bigger. For
  69. that reason most of these unused exports will soon be removed. This
  70. option is provided temporarily to provide a transition period in case
  71. some external kernel module needs one of these symbols anyway. If you
  72. encounter such a case in your module, consider if you are actually
  73. using the right API. (rationale: since nobody in the kernel is using
  74. this in a module, there is a pretty good chance it's actually the
  75. wrong interface to use). If you really need the symbol, please send a
  76. mail to the linux kernel mailing list mentioning the symbol and why
  77. you really need it, and what the merge plan to the mainline kernel for
  78. your module is.
  79. config DEBUG_FS
  80. bool "Debug Filesystem"
  81. help
  82. debugfs is a virtual file system that kernel developers use to put
  83. debugging files into. Enable this option to be able to read and
  84. write to these files.
  85. For detailed documentation on the debugfs API, see
  86. Documentation/DocBook/filesystems.
  87. If unsure, say N.
  88. config HEADERS_CHECK
  89. bool "Run 'make headers_check' when building vmlinux"
  90. depends on !UML
  91. help
  92. This option will extract the user-visible kernel headers whenever
  93. building the kernel, and will run basic sanity checks on them to
  94. ensure that exported files do not attempt to include files which
  95. were not exported, etc.
  96. If you're making modifications to header files which are
  97. relevant for userspace, say 'Y', and check the headers
  98. exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
  99. your build tree), to make sure they're suitable.
  100. config DEBUG_SECTION_MISMATCH
  101. bool "Enable full Section mismatch analysis"
  102. help
  103. The section mismatch analysis checks if there are illegal
  104. references from one section to another section.
  105. During linktime or runtime, some sections are dropped;
  106. any use of code/data previously in these sections would
  107. most likely result in an oops.
  108. In the code, functions and variables are annotated with
  109. __init, __devinit, etc. (see the full list in include/linux/init.h),
  110. which results in the code/data being placed in specific sections.
  111. The section mismatch analysis is always performed after a full
  112. kernel build, and enabling this option causes the following
  113. additional steps to occur:
  114. - Add the option -fno-inline-functions-called-once to gcc commands.
  115. When inlining a function annotated with __init in a non-init
  116. function, we would lose the section information and thus
  117. the analysis would not catch the illegal reference.
  118. This option tells gcc to inline less (but it does result in
  119. a larger kernel).
  120. - Run the section mismatch analysis for each module/built-in.o file.
  121. When we run the section mismatch analysis on vmlinux.o, we
  122. lose valueble information about where the mismatch was
  123. introduced.
  124. Running the analysis for each module/built-in.o file
  125. tells where the mismatch happens much closer to the
  126. source. The drawback is that the same mismatch is
  127. reported at least twice.
  128. - Enable verbose reporting from modpost in order to help resolve
  129. the section mismatches that are reported.
  130. config DEBUG_KERNEL
  131. bool "Kernel debugging"
  132. help
  133. Say Y here if you are developing drivers or trying to debug and
  134. identify kernel problems.
  135. config DEBUG_SHIRQ
  136. bool "Debug shared IRQ handlers"
  137. depends on DEBUG_KERNEL && GENERIC_HARDIRQS
  138. help
  139. Enable this to generate a spurious interrupt as soon as a shared
  140. interrupt handler is registered, and just before one is deregistered.
  141. Drivers ought to be able to handle interrupts coming in at those
  142. points; some don't and need to be caught.
  143. config LOCKUP_DETECTOR
  144. bool "Detect Hard and Soft Lockups"
  145. depends on DEBUG_KERNEL && !S390
  146. help
  147. Say Y here to enable the kernel to act as a watchdog to detect
  148. hard and soft lockups.
  149. Softlockups are bugs that cause the kernel to loop in kernel
  150. mode for more than 20 seconds, without giving other tasks a
  151. chance to run. The current stack trace is displayed upon
  152. detection and the system will stay locked up.
  153. Hardlockups are bugs that cause the CPU to loop in kernel mode
  154. for more than 10 seconds, without letting other interrupts have a
  155. chance to run. The current stack trace is displayed upon detection
  156. and the system will stay locked up.
  157. The overhead should be minimal. A periodic hrtimer runs to
  158. generate interrupts and kick the watchdog task every 4 seconds.
  159. An NMI is generated every 10 seconds or so to check for hardlockups.
  160. If NMIs are not available on the platform, every 12 seconds the
  161. hrtimer interrupt on one cpu will be used to check for hardlockups
  162. on the next cpu.
  163. The frequency of hrtimer and NMI events and the soft and hard lockup
  164. thresholds can be controlled through the sysctl watchdog_thresh.
  165. config HARDLOCKUP_DETECTOR_NMI
  166. def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
  167. !HAVE_NMI_WATCHDOG
  168. config HARDLOCKUP_DETECTOR_OTHER_CPU
  169. def_bool LOCKUP_DETECTOR && SMP && !HARDLOCKUP_DETECTOR_NMI && \
  170. !HAVE_NMI_WATCHDOG
  171. config HARDLOCKUP_DETECTOR
  172. def_bool HARDLOCKUP_DETECTOR_NMI || HARDLOCKUP_DETECTOR_OTHER_CPU
  173. config BOOTPARAM_HARDLOCKUP_PANIC
  174. bool "Panic (Reboot) On Hard Lockups"
  175. depends on LOCKUP_DETECTOR
  176. help
  177. Say Y here to enable the kernel to panic on "hard lockups",
  178. which are bugs that cause the kernel to loop in kernel
  179. mode with interrupts disabled for more than 10 seconds (configurable
  180. using the watchdog_thresh sysctl).
  181. Say N if unsure.
  182. config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
  183. int
  184. depends on LOCKUP_DETECTOR
  185. range 0 1
  186. default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
  187. default 1 if BOOTPARAM_HARDLOCKUP_PANIC
  188. config BOOTPARAM_SOFTLOCKUP_PANIC
  189. bool "Panic (Reboot) On Soft Lockups"
  190. depends on LOCKUP_DETECTOR
  191. help
  192. Say Y here to enable the kernel to panic on "soft lockups",
  193. which are bugs that cause the kernel to loop in kernel
  194. mode for more than 20 seconds (configurable using the watchdog_thresh
  195. sysctl), without giving other tasks a chance to run.
  196. The panic can be used in combination with panic_timeout,
  197. to cause the system to reboot automatically after a
  198. lockup has been detected. This feature is useful for
  199. high-availability systems that have uptime guarantees and
  200. where a lockup must be resolved ASAP.
  201. Say N if unsure.
  202. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  203. int
  204. depends on LOCKUP_DETECTOR
  205. range 0 1
  206. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  207. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  208. config DETECT_HUNG_TASK
  209. bool "Detect Hung Tasks"
  210. depends on DEBUG_KERNEL
  211. default LOCKUP_DETECTOR
  212. help
  213. Say Y here to enable the kernel to detect "hung tasks",
  214. which are bugs that cause the task to be stuck in
  215. uninterruptible "D" state indefinitiley.
  216. When a hung task is detected, the kernel will print the
  217. current stack trace (which you should report), but the
  218. task will stay in uninterruptible state. If lockdep is
  219. enabled then all held locks will also be reported. This
  220. feature has negligible overhead.
  221. config DEFAULT_HUNG_TASK_TIMEOUT
  222. int "Default timeout for hung task detection (in seconds)"
  223. depends on DETECT_HUNG_TASK
  224. default 120
  225. help
  226. This option controls the default timeout (in seconds) used
  227. to determine when a task has become non-responsive and should
  228. be considered hung.
  229. It can be adjusted at runtime via the kernel.hung_task_timeout_secs
  230. sysctl or by writing a value to
  231. /proc/sys/kernel/hung_task_timeout_secs.
  232. A timeout of 0 disables the check. The default is two minutes.
  233. Keeping the default should be fine in most cases.
  234. config BOOTPARAM_HUNG_TASK_PANIC
  235. bool "Panic (Reboot) On Hung Tasks"
  236. depends on DETECT_HUNG_TASK
  237. help
  238. Say Y here to enable the kernel to panic on "hung tasks",
  239. which are bugs that cause the kernel to leave a task stuck
  240. in uninterruptible "D" state.
  241. The panic can be used in combination with panic_timeout,
  242. to cause the system to reboot automatically after a
  243. hung task has been detected. This feature is useful for
  244. high-availability systems that have uptime guarantees and
  245. where a hung tasks must be resolved ASAP.
  246. Say N if unsure.
  247. config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  248. int
  249. depends on DETECT_HUNG_TASK
  250. range 0 1
  251. default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  252. default 1 if BOOTPARAM_HUNG_TASK_PANIC
  253. config SCHED_DEBUG
  254. bool "Collect scheduler debugging info"
  255. depends on DEBUG_KERNEL && PROC_FS
  256. default y
  257. help
  258. If you say Y here, the /proc/sched_debug file will be provided
  259. that can help debug the scheduler. The runtime overhead of this
  260. option is minimal.
  261. config SYSRQ_SCHED_DEBUG
  262. bool "Print scheduling debugging info from sysrq-trigger"
  263. depends on SCHED_DEBUG
  264. default y
  265. help
  266. If you say Y here, the "show-task-states(T)" and
  267. "show-blocked-tasks(W)" sysrq-triggers will print additional
  268. scheduling statistics.
  269. config SCHEDSTATS
  270. bool "Collect scheduler statistics"
  271. depends on DEBUG_KERNEL && PROC_FS
  272. help
  273. If you say Y here, additional code will be inserted into the
  274. scheduler and related routines to collect statistics about
  275. scheduler behavior and provide them in /proc/schedstat. These
  276. stats may be useful for both tuning and debugging the scheduler
  277. If you aren't debugging the scheduler or trying to tune a specific
  278. application, you can say N to avoid the very slight overhead
  279. this adds.
  280. config DEBUG_OBJECTS
  281. bool "Debug object operations"
  282. depends on DEBUG_KERNEL
  283. help
  284. If you say Y here, additional code will be inserted into the
  285. kernel to track the life time of various objects and validate
  286. the operations on those objects.
  287. config DEBUG_OBJECTS_SELFTEST
  288. bool "Debug objects selftest"
  289. depends on DEBUG_OBJECTS
  290. help
  291. This enables the selftest of the object debug code.
  292. config DEBUG_OBJECTS_FREE
  293. bool "Debug objects in freed memory"
  294. depends on DEBUG_OBJECTS
  295. help
  296. This enables checks whether a k/v free operation frees an area
  297. which contains an object which has not been deactivated
  298. properly. This can make kmalloc/kfree-intensive workloads
  299. much slower.
  300. config DEBUG_OBJECTS_TIMERS
  301. bool "Debug timer objects"
  302. depends on DEBUG_OBJECTS
  303. help
  304. If you say Y here, additional code will be inserted into the
  305. timer routines to track the life time of timer objects and
  306. validate the timer operations.
  307. config DEBUG_OBJECTS_WORK
  308. bool "Debug work objects"
  309. depends on DEBUG_OBJECTS
  310. help
  311. If you say Y here, additional code will be inserted into the
  312. work queue routines to track the life time of work objects and
  313. validate the work operations.
  314. config DEBUG_OBJECTS_RCU_HEAD
  315. bool "Debug RCU callbacks objects"
  316. depends on DEBUG_OBJECTS
  317. help
  318. Enable this to turn on debugging of RCU list heads (call_rcu() usage).
  319. config DEBUG_OBJECTS_PERCPU_COUNTER
  320. bool "Debug percpu counter objects"
  321. depends on DEBUG_OBJECTS
  322. help
  323. If you say Y here, additional code will be inserted into the
  324. percpu counter routines to track the life time of percpu counter
  325. objects and validate the percpu counter operations.
  326. config DEBUG_OBJECTS_ENABLE_DEFAULT
  327. int "debug_objects bootup default value (0-1)"
  328. range 0 1
  329. default "1"
  330. depends on DEBUG_OBJECTS
  331. help
  332. Debug objects boot parameter default value
  333. config DEBUG_SLAB
  334. bool "Debug slab memory allocations"
  335. depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
  336. help
  337. Say Y here to have the kernel do limited verification on memory
  338. allocation as well as poisoning memory on free to catch use of freed
  339. memory. This can make kmalloc/kfree-intensive workloads much slower.
  340. config DEBUG_SLAB_LEAK
  341. bool "Memory leak debugging"
  342. depends on DEBUG_SLAB
  343. config SLUB_DEBUG_ON
  344. bool "SLUB debugging on by default"
  345. depends on SLUB && SLUB_DEBUG && !KMEMCHECK
  346. default n
  347. help
  348. Boot with debugging on by default. SLUB boots by default with
  349. the runtime debug capabilities switched off. Enabling this is
  350. equivalent to specifying the "slub_debug" parameter on boot.
  351. There is no support for more fine grained debug control like
  352. possible with slub_debug=xxx. SLUB debugging may be switched
  353. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  354. "slub_debug=-".
  355. config SLUB_STATS
  356. default n
  357. bool "Enable SLUB performance statistics"
  358. depends on SLUB && SYSFS
  359. help
  360. SLUB statistics are useful to debug SLUBs allocation behavior in
  361. order find ways to optimize the allocator. This should never be
  362. enabled for production use since keeping statistics slows down
  363. the allocator by a few percentage points. The slabinfo command
  364. supports the determination of the most active slabs to figure
  365. out which slabs are relevant to a particular load.
  366. Try running: slabinfo -DA
  367. config DEBUG_KMEMLEAK
  368. bool "Kernel memory leak detector"
  369. depends on DEBUG_KERNEL && EXPERIMENTAL && \
  370. (X86 || ARM || PPC || MIPS || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
  371. select DEBUG_FS
  372. select STACKTRACE if STACKTRACE_SUPPORT
  373. select KALLSYMS
  374. select CRC32
  375. help
  376. Say Y here if you want to enable the memory leak
  377. detector. The memory allocation/freeing is traced in a way
  378. similar to the Boehm's conservative garbage collector, the
  379. difference being that the orphan objects are not freed but
  380. only shown in /sys/kernel/debug/kmemleak. Enabling this
  381. feature will introduce an overhead to memory
  382. allocations. See Documentation/kmemleak.txt for more
  383. details.
  384. Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  385. of finding leaks due to the slab objects poisoning.
  386. In order to access the kmemleak file, debugfs needs to be
  387. mounted (usually at /sys/kernel/debug).
  388. config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
  389. int "Maximum kmemleak early log entries"
  390. depends on DEBUG_KMEMLEAK
  391. range 200 40000
  392. default 800
  393. help
  394. Kmemleak must track all the memory allocations to avoid
  395. reporting false positives. Since memory may be allocated or
  396. freed before kmemleak is initialised, an early log buffer is
  397. used to store these actions. If kmemleak reports "early log
  398. buffer exceeded", please increase this value.
  399. config DEBUG_KMEMLEAK_TEST
  400. tristate "Simple test for the kernel memory leak detector"
  401. depends on DEBUG_KMEMLEAK && m
  402. help
  403. This option enables a module that explicitly leaks memory.
  404. If unsure, say N.
  405. config DEBUG_KMEMLEAK_DEFAULT_OFF
  406. bool "Default kmemleak to off"
  407. depends on DEBUG_KMEMLEAK
  408. help
  409. Say Y here to disable kmemleak by default. It can then be enabled
  410. on the command line via kmemleak=on.
  411. config DEBUG_PREEMPT
  412. bool "Debug preemptible kernel"
  413. depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
  414. default y
  415. help
  416. If you say Y here then the kernel will use a debug variant of the
  417. commonly used smp_processor_id() function and will print warnings
  418. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  419. will detect preemption count underflows.
  420. config DEBUG_RT_MUTEXES
  421. bool "RT Mutex debugging, deadlock detection"
  422. depends on DEBUG_KERNEL && RT_MUTEXES
  423. help
  424. This allows rt mutex semantics violations and rt mutex related
  425. deadlocks (lockups) to be detected and reported automatically.
  426. config DEBUG_PI_LIST
  427. bool
  428. default y
  429. depends on DEBUG_RT_MUTEXES
  430. config RT_MUTEX_TESTER
  431. bool "Built-in scriptable tester for rt-mutexes"
  432. depends on DEBUG_KERNEL && RT_MUTEXES
  433. help
  434. This option enables a rt-mutex tester.
  435. config DEBUG_SPINLOCK
  436. bool "Spinlock and rw-lock debugging: basic checks"
  437. depends on DEBUG_KERNEL
  438. select UNINLINE_SPIN_UNLOCK
  439. help
  440. Say Y here and build SMP to catch missing spinlock initialization
  441. and certain other kinds of spinlock errors commonly made. This is
  442. best used in conjunction with the NMI watchdog so that spinlock
  443. deadlocks are also debuggable.
  444. config DEBUG_MUTEXES
  445. bool "Mutex debugging: basic checks"
  446. depends on DEBUG_KERNEL
  447. help
  448. This feature allows mutex semantics violations to be detected and
  449. reported.
  450. config DEBUG_LOCK_ALLOC
  451. bool "Lock debugging: detect incorrect freeing of live locks"
  452. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  453. select DEBUG_SPINLOCK
  454. select DEBUG_MUTEXES
  455. select LOCKDEP
  456. help
  457. This feature will check whether any held lock (spinlock, rwlock,
  458. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  459. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  460. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  461. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  462. held during task exit.
  463. config PROVE_LOCKING
  464. bool "Lock debugging: prove locking correctness"
  465. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  466. select LOCKDEP
  467. select DEBUG_SPINLOCK
  468. select DEBUG_MUTEXES
  469. select DEBUG_LOCK_ALLOC
  470. select TRACE_IRQFLAGS
  471. default n
  472. help
  473. This feature enables the kernel to prove that all locking
  474. that occurs in the kernel runtime is mathematically
  475. correct: that under no circumstance could an arbitrary (and
  476. not yet triggered) combination of observed locking
  477. sequences (on an arbitrary number of CPUs, running an
  478. arbitrary number of tasks and interrupt contexts) cause a
  479. deadlock.
  480. In short, this feature enables the kernel to report locking
  481. related deadlocks before they actually occur.
  482. The proof does not depend on how hard and complex a
  483. deadlock scenario would be to trigger: how many
  484. participant CPUs, tasks and irq-contexts would be needed
  485. for it to trigger. The proof also does not depend on
  486. timing: if a race and a resulting deadlock is possible
  487. theoretically (no matter how unlikely the race scenario
  488. is), it will be proven so and will immediately be
  489. reported by the kernel (once the event is observed that
  490. makes the deadlock theoretically possible).
  491. If a deadlock is impossible (i.e. the locking rules, as
  492. observed by the kernel, are mathematically correct), the
  493. kernel reports nothing.
  494. NOTE: this feature can also be enabled for rwlocks, mutexes
  495. and rwsems - in which case all dependencies between these
  496. different locking variants are observed and mapped too, and
  497. the proof of observed correctness is also maintained for an
  498. arbitrary combination of these separate locking variants.
  499. For more details, see Documentation/lockdep-design.txt.
  500. config PROVE_RCU
  501. bool "RCU debugging: prove RCU correctness"
  502. depends on PROVE_LOCKING
  503. default n
  504. help
  505. This feature enables lockdep extensions that check for correct
  506. use of RCU APIs. This is currently under development. Say Y
  507. if you want to debug RCU usage or help work on the PROVE_RCU
  508. feature.
  509. Say N if you are unsure.
  510. config PROVE_RCU_REPEATEDLY
  511. bool "RCU debugging: don't disable PROVE_RCU on first splat"
  512. depends on PROVE_RCU
  513. default n
  514. help
  515. By itself, PROVE_RCU will disable checking upon issuing the
  516. first warning (or "splat"). This feature prevents such
  517. disabling, allowing multiple RCU-lockdep warnings to be printed
  518. on a single reboot.
  519. Say Y to allow multiple RCU-lockdep warnings per boot.
  520. Say N if you are unsure.
  521. config SPARSE_RCU_POINTER
  522. bool "RCU debugging: sparse-based checks for pointer usage"
  523. default n
  524. help
  525. This feature enables the __rcu sparse annotation for
  526. RCU-protected pointers. This annotation will cause sparse
  527. to flag any non-RCU used of annotated pointers. This can be
  528. helpful when debugging RCU usage. Please note that this feature
  529. is not intended to enforce code cleanliness; it is instead merely
  530. a debugging aid.
  531. Say Y to make sparse flag questionable use of RCU-protected pointers
  532. Say N if you are unsure.
  533. config LOCKDEP
  534. bool
  535. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  536. select STACKTRACE
  537. select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
  538. select KALLSYMS
  539. select KALLSYMS_ALL
  540. config LOCK_STAT
  541. bool "Lock usage statistics"
  542. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  543. select LOCKDEP
  544. select DEBUG_SPINLOCK
  545. select DEBUG_MUTEXES
  546. select DEBUG_LOCK_ALLOC
  547. default n
  548. help
  549. This feature enables tracking lock contention points
  550. For more details, see Documentation/lockstat.txt
  551. This also enables lock events required by "perf lock",
  552. subcommand of perf.
  553. If you want to use "perf lock", you also need to turn on
  554. CONFIG_EVENT_TRACING.
  555. CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
  556. (CONFIG_LOCKDEP defines "acquire" and "release" events.)
  557. config DEBUG_LOCKDEP
  558. bool "Lock dependency engine debugging"
  559. depends on DEBUG_KERNEL && LOCKDEP
  560. help
  561. If you say Y here, the lock dependency engine will do
  562. additional runtime checks to debug itself, at the price
  563. of more runtime overhead.
  564. config TRACE_IRQFLAGS
  565. bool
  566. help
  567. Enables hooks to interrupt enabling and disabling for
  568. either tracing or lock debugging.
  569. config DEBUG_ATOMIC_SLEEP
  570. bool "Sleep inside atomic section checking"
  571. select PREEMPT_COUNT
  572. depends on DEBUG_KERNEL
  573. help
  574. If you say Y here, various routines which may sleep will become very
  575. noisy if they are called inside atomic sections: when a spinlock is
  576. held, inside an rcu read side critical section, inside preempt disabled
  577. sections, inside an interrupt, etc...
  578. config DEBUG_LOCKING_API_SELFTESTS
  579. bool "Locking API boot-time self-tests"
  580. depends on DEBUG_KERNEL
  581. help
  582. Say Y here if you want the kernel to run a short self-test during
  583. bootup. The self-test checks whether common types of locking bugs
  584. are detected by debugging mechanisms or not. (if you disable
  585. lock debugging then those bugs wont be detected of course.)
  586. The following locking APIs are covered: spinlocks, rwlocks,
  587. mutexes and rwsems.
  588. config STACKTRACE
  589. bool "Stacktrace"
  590. depends on STACKTRACE_SUPPORT
  591. default y
  592. config DEBUG_STACK_USAGE
  593. bool "Stack utilization instrumentation"
  594. depends on DEBUG_KERNEL
  595. help
  596. Enables the display of the minimum amount of free stack which each
  597. task has ever had available in the sysrq-T and sysrq-P debug output.
  598. This option will slow down process creation somewhat.
  599. config DEBUG_KOBJECT
  600. bool "kobject debugging"
  601. depends on DEBUG_KERNEL
  602. help
  603. If you say Y here, some extra kobject debugging messages will be sent
  604. to the syslog.
  605. config DEBUG_HIGHMEM
  606. bool "Highmem debugging"
  607. depends on DEBUG_KERNEL && HIGHMEM
  608. help
  609. This options enables addition error checking for high memory systems.
  610. Disable for production systems.
  611. config DEBUG_BUGVERBOSE
  612. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
  613. depends on BUG
  614. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  615. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 || TILE
  616. default y
  617. help
  618. Say Y here to make BUG() panics output the file name and line number
  619. of the BUG call as well as the EIP and oops trace. This aids
  620. debugging but costs about 70-100K of memory.
  621. config DEBUG_INFO
  622. bool "Compile the kernel with debug info"
  623. depends on DEBUG_KERNEL
  624. help
  625. If you say Y here the resulting kernel image will include
  626. debugging info resulting in a larger kernel image.
  627. This adds debug symbols to the kernel and modules (gcc -g), and
  628. is needed if you intend to use kernel crashdump or binary object
  629. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  630. Say Y here only if you plan to debug the kernel.
  631. If unsure, say N.
  632. config DEBUG_INFO_REDUCED
  633. bool "Reduce debugging information"
  634. depends on DEBUG_INFO
  635. help
  636. If you say Y here gcc is instructed to generate less debugging
  637. information for structure types. This means that tools that
  638. need full debugging information (like kgdb or systemtap) won't
  639. be happy. But if you merely need debugging information to
  640. resolve line numbers there is no loss. Advantage is that
  641. build directory object sizes shrink dramatically over a full
  642. DEBUG_INFO build and compile times are reduced too.
  643. Only works with newer gcc versions.
  644. config DEBUG_VM
  645. bool "Debug VM"
  646. depends on DEBUG_KERNEL
  647. help
  648. Enable this to turn on extended checks in the virtual-memory system
  649. that may impact performance.
  650. If unsure, say N.
  651. config DEBUG_VIRTUAL
  652. bool "Debug VM translations"
  653. depends on DEBUG_KERNEL && X86
  654. help
  655. Enable some costly sanity checks in virtual to page code. This can
  656. catch mistakes with virt_to_page() and friends.
  657. If unsure, say N.
  658. config DEBUG_NOMMU_REGIONS
  659. bool "Debug the global anon/private NOMMU mapping region tree"
  660. depends on DEBUG_KERNEL && !MMU
  661. help
  662. This option causes the global tree of anonymous and private mapping
  663. regions to be regularly checked for invalid topology.
  664. config DEBUG_WRITECOUNT
  665. bool "Debug filesystem writers count"
  666. depends on DEBUG_KERNEL
  667. help
  668. Enable this to catch wrong use of the writers count in struct
  669. vfsmount. This will increase the size of each file struct by
  670. 32 bits.
  671. If unsure, say N.
  672. config DEBUG_MEMORY_INIT
  673. bool "Debug memory initialisation" if EXPERT
  674. default !EXPERT
  675. help
  676. Enable this for additional checks during memory initialisation.
  677. The sanity checks verify aspects of the VM such as the memory model
  678. and other information provided by the architecture. Verbose
  679. information will be printed at KERN_DEBUG loglevel depending
  680. on the mminit_loglevel= command-line option.
  681. If unsure, say Y
  682. config DEBUG_LIST
  683. bool "Debug linked list manipulation"
  684. depends on DEBUG_KERNEL
  685. help
  686. Enable this to turn on extended checks in the linked-list
  687. walking routines.
  688. If unsure, say N.
  689. config TEST_LIST_SORT
  690. bool "Linked list sorting test"
  691. depends on DEBUG_KERNEL
  692. help
  693. Enable this to turn on 'list_sort()' function test. This test is
  694. executed only once during system boot, so affects only boot time.
  695. If unsure, say N.
  696. config DEBUG_SG
  697. bool "Debug SG table operations"
  698. depends on DEBUG_KERNEL
  699. help
  700. Enable this to turn on checks on scatter-gather tables. This can
  701. help find problems with drivers that do not properly initialize
  702. their sg tables.
  703. If unsure, say N.
  704. config DEBUG_NOTIFIERS
  705. bool "Debug notifier call chains"
  706. depends on DEBUG_KERNEL
  707. help
  708. Enable this to turn on sanity checking for notifier call chains.
  709. This is most useful for kernel developers to make sure that
  710. modules properly unregister themselves from notifier chains.
  711. This is a relatively cheap check but if you care about maximum
  712. performance, say N.
  713. config DEBUG_CREDENTIALS
  714. bool "Debug credential management"
  715. depends on DEBUG_KERNEL
  716. help
  717. Enable this to turn on some debug checking for credential
  718. management. The additional code keeps track of the number of
  719. pointers from task_structs to any given cred struct, and checks to
  720. see that this number never exceeds the usage count of the cred
  721. struct.
  722. Furthermore, if SELinux is enabled, this also checks that the
  723. security pointer in the cred struct is never seen to be invalid.
  724. If unsure, say N.
  725. #
  726. # Select this config option from the architecture Kconfig, if it
  727. # is preferred to always offer frame pointers as a config
  728. # option on the architecture (regardless of KERNEL_DEBUG):
  729. #
  730. config ARCH_WANT_FRAME_POINTERS
  731. bool
  732. help
  733. config FRAME_POINTER
  734. bool "Compile the kernel with frame pointers"
  735. depends on DEBUG_KERNEL && \
  736. (CRIS || M68K || FRV || UML || \
  737. AVR32 || SUPERH || BLACKFIN || MN10300) || \
  738. ARCH_WANT_FRAME_POINTERS
  739. default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
  740. help
  741. If you say Y here the resulting kernel image will be slightly
  742. larger and slower, but it gives very useful debugging information
  743. in case of kernel bugs. (precise oopses/stacktraces/warnings)
  744. config BOOT_PRINTK_DELAY
  745. bool "Delay each boot printk message by N milliseconds"
  746. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  747. help
  748. This build option allows you to read kernel boot messages
  749. by inserting a short delay after each one. The delay is
  750. specified in milliseconds on the kernel command line,
  751. using "boot_delay=N".
  752. It is likely that you would also need to use "lpj=M" to preset
  753. the "loops per jiffie" value.
  754. See a previous boot log for the "lpj" value to use for your
  755. system, and then set "lpj=M" before setting "boot_delay=N".
  756. NOTE: Using this option may adversely affect SMP systems.
  757. I.e., processors other than the first one may not boot up.
  758. BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
  759. what it believes to be lockup conditions.
  760. config RCU_TORTURE_TEST
  761. tristate "torture tests for RCU"
  762. depends on DEBUG_KERNEL
  763. default n
  764. help
  765. This option provides a kernel module that runs torture tests
  766. on the RCU infrastructure. The kernel module may be built
  767. after the fact on the running kernel to be tested, if desired.
  768. Say Y here if you want RCU torture tests to be built into
  769. the kernel.
  770. Say M if you want the RCU torture tests to build as a module.
  771. Say N if you are unsure.
  772. config RCU_TORTURE_TEST_RUNNABLE
  773. bool "torture tests for RCU runnable by default"
  774. depends on RCU_TORTURE_TEST = y
  775. default n
  776. help
  777. This option provides a way to build the RCU torture tests
  778. directly into the kernel without them starting up at boot
  779. time. You can use /proc/sys/kernel/rcutorture_runnable
  780. to manually override this setting. This /proc file is
  781. available only when the RCU torture tests have been built
  782. into the kernel.
  783. Say Y here if you want the RCU torture tests to start during
  784. boot (you probably don't).
  785. Say N here if you want the RCU torture tests to start only
  786. after being manually enabled via /proc.
  787. config RCU_CPU_STALL_TIMEOUT
  788. int "RCU CPU stall timeout in seconds"
  789. depends on TREE_RCU || TREE_PREEMPT_RCU
  790. range 3 300
  791. default 60
  792. help
  793. If a given RCU grace period extends more than the specified
  794. number of seconds, a CPU stall warning is printed. If the
  795. RCU grace period persists, additional CPU stall warnings are
  796. printed at more widely spaced intervals.
  797. config RCU_CPU_STALL_VERBOSE
  798. bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
  799. depends on TREE_PREEMPT_RCU
  800. default y
  801. help
  802. This option causes RCU to printk detailed per-task information
  803. for any tasks that are stalling the current RCU grace period.
  804. Say N if you are unsure.
  805. Say Y if you want to enable such checks.
  806. config RCU_CPU_STALL_INFO
  807. bool "Print additional diagnostics on RCU CPU stall"
  808. depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
  809. default n
  810. help
  811. For each stalled CPU that is aware of the current RCU grace
  812. period, print out additional per-CPU diagnostic information
  813. regarding scheduling-clock ticks, idle state, and,
  814. for RCU_FAST_NO_HZ kernels, idle-entry state.
  815. Say N if you are unsure.
  816. Say Y if you want to enable such diagnostics.
  817. config RCU_TRACE
  818. bool "Enable tracing for RCU"
  819. depends on DEBUG_KERNEL
  820. help
  821. This option provides tracing in RCU which presents stats
  822. in debugfs for debugging RCU implementation.
  823. Say Y here if you want to enable RCU tracing
  824. Say N if you are unsure.
  825. config KPROBES_SANITY_TEST
  826. bool "Kprobes sanity tests"
  827. depends on DEBUG_KERNEL
  828. depends on KPROBES
  829. default n
  830. help
  831. This option provides for testing basic kprobes functionality on
  832. boot. A sample kprobe, jprobe and kretprobe are inserted and
  833. verified for functionality.
  834. Say N if you are unsure.
  835. config BACKTRACE_SELF_TEST
  836. tristate "Self test for the backtrace code"
  837. depends on DEBUG_KERNEL
  838. default n
  839. help
  840. This option provides a kernel module that can be used to test
  841. the kernel stack backtrace code. This option is not useful
  842. for distributions or general kernels, but only for kernel
  843. developers working on architecture code.
  844. Note that if you want to also test saved backtraces, you will
  845. have to enable STACKTRACE as well.
  846. Say N if you are unsure.
  847. config DEBUG_BLOCK_EXT_DEVT
  848. bool "Force extended block device numbers and spread them"
  849. depends on DEBUG_KERNEL
  850. depends on BLOCK
  851. default n
  852. help
  853. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  854. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  855. YOU ARE DOING. Distros, please enable this and fix whatever
  856. is broken.
  857. Conventionally, block device numbers are allocated from
  858. predetermined contiguous area. However, extended block area
  859. may introduce non-contiguous block device numbers. This
  860. option forces most block device numbers to be allocated from
  861. the extended space and spreads them to discover kernel or
  862. userland code paths which assume predetermined contiguous
  863. device number allocation.
  864. Note that turning on this debug option shuffles all the
  865. device numbers for all IDE and SCSI devices including libata
  866. ones, so root partition specified using device number
  867. directly (via rdev or root=MAJ:MIN) won't work anymore.
  868. Textual device names (root=/dev/sdXn) will continue to work.
  869. Say N if you are unsure.
  870. config DEBUG_FORCE_WEAK_PER_CPU
  871. bool "Force weak per-cpu definitions"
  872. depends on DEBUG_KERNEL
  873. help
  874. s390 and alpha require percpu variables in modules to be
  875. defined weak to work around addressing range issue which
  876. puts the following two restrictions on percpu variable
  877. definitions.
  878. 1. percpu symbols must be unique whether static or not
  879. 2. percpu variables can't be defined inside a function
  880. To ensure that generic code follows the above rules, this
  881. option forces all percpu variables to be defined as weak.
  882. config DEBUG_PER_CPU_MAPS
  883. bool "Debug access to per_cpu maps"
  884. depends on DEBUG_KERNEL
  885. depends on SMP
  886. help
  887. Say Y to verify that the per_cpu map being accessed has
  888. been set up. This adds a fair amount of code to kernel memory
  889. and decreases performance.
  890. Say N if unsure.
  891. config LKDTM
  892. tristate "Linux Kernel Dump Test Tool Module"
  893. depends on DEBUG_FS
  894. depends on BLOCK
  895. default n
  896. help
  897. This module enables testing of the different dumping mechanisms by
  898. inducing system failures at predefined crash points.
  899. If you don't need it: say N
  900. Choose M here to compile this code as a module. The module will be
  901. called lkdtm.
  902. Documentation on how to use the module can be found in
  903. Documentation/fault-injection/provoke-crashes.txt
  904. config CPU_NOTIFIER_ERROR_INJECT
  905. tristate "CPU notifier error injection module"
  906. depends on HOTPLUG_CPU && DEBUG_KERNEL
  907. help
  908. This option provides a kernel module that can be used to test
  909. the error handling of the cpu notifiers
  910. To compile this code as a module, choose M here: the module will
  911. be called cpu-notifier-error-inject.
  912. If unsure, say N.
  913. config FAULT_INJECTION
  914. bool "Fault-injection framework"
  915. depends on DEBUG_KERNEL
  916. help
  917. Provide fault-injection framework.
  918. For more details, see Documentation/fault-injection/.
  919. config FAILSLAB
  920. bool "Fault-injection capability for kmalloc"
  921. depends on FAULT_INJECTION
  922. depends on SLAB || SLUB
  923. help
  924. Provide fault-injection capability for kmalloc.
  925. config FAIL_PAGE_ALLOC
  926. bool "Fault-injection capabilitiy for alloc_pages()"
  927. depends on FAULT_INJECTION
  928. help
  929. Provide fault-injection capability for alloc_pages().
  930. config FAIL_MAKE_REQUEST
  931. bool "Fault-injection capability for disk IO"
  932. depends on FAULT_INJECTION && BLOCK
  933. help
  934. Provide fault-injection capability for disk IO.
  935. config FAIL_IO_TIMEOUT
  936. bool "Fault-injection capability for faking disk interrupts"
  937. depends on FAULT_INJECTION && BLOCK
  938. help
  939. Provide fault-injection capability on end IO handling. This
  940. will make the block layer "forget" an interrupt as configured,
  941. thus exercising the error handling.
  942. Only works with drivers that use the generic timeout handling,
  943. for others it wont do anything.
  944. config FAIL_MMC_REQUEST
  945. bool "Fault-injection capability for MMC IO"
  946. select DEBUG_FS
  947. depends on FAULT_INJECTION && MMC
  948. help
  949. Provide fault-injection capability for MMC IO.
  950. This will make the mmc core return data errors. This is
  951. useful to test the error handling in the mmc block device
  952. and to test how the mmc host driver handles retries from
  953. the block device.
  954. config FAULT_INJECTION_DEBUG_FS
  955. bool "Debugfs entries for fault-injection capabilities"
  956. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  957. help
  958. Enable configuration of fault-injection capabilities via debugfs.
  959. config FAULT_INJECTION_STACKTRACE_FILTER
  960. bool "stacktrace filter for fault-injection capabilities"
  961. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  962. depends on !X86_64
  963. select STACKTRACE
  964. select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  965. help
  966. Provide stacktrace filter for fault-injection capabilities
  967. config LATENCYTOP
  968. bool "Latency measuring infrastructure"
  969. depends on HAVE_LATENCYTOP_SUPPORT
  970. depends on DEBUG_KERNEL
  971. depends on STACKTRACE_SUPPORT
  972. depends on PROC_FS
  973. select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  974. select KALLSYMS
  975. select KALLSYMS_ALL
  976. select STACKTRACE
  977. select SCHEDSTATS
  978. select SCHED_DEBUG
  979. help
  980. Enable this option if you want to use the LatencyTOP tool
  981. to find out which userspace is blocking on what kernel operations.
  982. source mm/Kconfig.debug
  983. source kernel/trace/Kconfig
  984. config PROVIDE_OHCI1394_DMA_INIT
  985. bool "Remote debugging over FireWire early on boot"
  986. depends on PCI && X86
  987. help
  988. If you want to debug problems which hang or crash the kernel early
  989. on boot and the crashing machine has a FireWire port, you can use
  990. this feature to remotely access the memory of the crashed machine
  991. over FireWire. This employs remote DMA as part of the OHCI1394
  992. specification which is now the standard for FireWire controllers.
  993. With remote DMA, you can monitor the printk buffer remotely using
  994. firescope and access all memory below 4GB using fireproxy from gdb.
  995. Even controlling a kernel debugger is possible using remote DMA.
  996. Usage:
  997. If ohci1394_dma=early is used as boot parameter, it will initialize
  998. all OHCI1394 controllers which are found in the PCI config space.
  999. As all changes to the FireWire bus such as enabling and disabling
  1000. devices cause a bus reset and thereby disable remote DMA for all
  1001. devices, be sure to have the cable plugged and FireWire enabled on
  1002. the debugging host before booting the debug target for debugging.
  1003. This code (~1k) is freed after boot. By then, the firewire stack
  1004. in charge of the OHCI-1394 controllers should be used instead.
  1005. See Documentation/debugging-via-ohci1394.txt for more information.
  1006. config FIREWIRE_OHCI_REMOTE_DMA
  1007. bool "Remote debugging over FireWire with firewire-ohci"
  1008. depends on FIREWIRE_OHCI
  1009. help
  1010. This option lets you use the FireWire bus for remote debugging
  1011. with help of the firewire-ohci driver. It enables unfiltered
  1012. remote DMA in firewire-ohci.
  1013. See Documentation/debugging-via-ohci1394.txt for more information.
  1014. If unsure, say N.
  1015. config BUILD_DOCSRC
  1016. bool "Build targets in Documentation/ tree"
  1017. depends on HEADERS_CHECK
  1018. help
  1019. This option attempts to build objects from the source files in the
  1020. kernel Documentation/ tree.
  1021. Say N if you are unsure.
  1022. config DYNAMIC_DEBUG
  1023. bool "Enable dynamic printk() support"
  1024. default n
  1025. depends on PRINTK
  1026. depends on DEBUG_FS
  1027. help
  1028. Compiles debug level messages into the kernel, which would not
  1029. otherwise be available at runtime. These messages can then be
  1030. enabled/disabled based on various levels of scope - per source file,
  1031. function, module, format string, and line number. This mechanism
  1032. implicitly enables all pr_debug() and dev_dbg() calls. The impact of
  1033. this compile option is a larger kernel text size of about 2%.
  1034. Usage:
  1035. Dynamic debugging is controlled via the 'dynamic_debug/control' file,
  1036. which is contained in the 'debugfs' filesystem. Thus, the debugfs
  1037. filesystem must first be mounted before making use of this feature.
  1038. We refer the control file as: <debugfs>/dynamic_debug/control. This
  1039. file contains a list of the debug statements that can be enabled. The
  1040. format for each line of the file is:
  1041. filename:lineno [module]function flags format
  1042. filename : source file of the debug statement
  1043. lineno : line number of the debug statement
  1044. module : module that contains the debug statement
  1045. function : function that contains the debug statement
  1046. flags : 'p' means the line is turned 'on' for printing
  1047. format : the format used for the debug statement
  1048. From a live system:
  1049. nullarbor:~ # cat <debugfs>/dynamic_debug/control
  1050. # filename:lineno [module]function flags format
  1051. fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
  1052. fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
  1053. fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
  1054. Example usage:
  1055. // enable the message at line 1603 of file svcsock.c
  1056. nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
  1057. <debugfs>/dynamic_debug/control
  1058. // enable all the messages in file svcsock.c
  1059. nullarbor:~ # echo -n 'file svcsock.c +p' >
  1060. <debugfs>/dynamic_debug/control
  1061. // enable all the messages in the NFS server module
  1062. nullarbor:~ # echo -n 'module nfsd +p' >
  1063. <debugfs>/dynamic_debug/control
  1064. // enable all 12 messages in the function svc_process()
  1065. nullarbor:~ # echo -n 'func svc_process +p' >
  1066. <debugfs>/dynamic_debug/control
  1067. // disable all 12 messages in the function svc_process()
  1068. nullarbor:~ # echo -n 'func svc_process -p' >
  1069. <debugfs>/dynamic_debug/control
  1070. See Documentation/dynamic-debug-howto.txt for additional information.
  1071. config DMA_API_DEBUG
  1072. bool "Enable debugging of DMA-API usage"
  1073. depends on HAVE_DMA_API_DEBUG
  1074. help
  1075. Enable this option to debug the use of the DMA API by device drivers.
  1076. With this option you will be able to detect common bugs in device
  1077. drivers like double-freeing of DMA mappings or freeing mappings that
  1078. were never allocated.
  1079. This option causes a performance degredation. Use only if you want
  1080. to debug device drivers. If unsure, say N.
  1081. config ATOMIC64_SELFTEST
  1082. bool "Perform an atomic64_t self-test at boot"
  1083. help
  1084. Enable this option to test the atomic64_t functions at boot.
  1085. If unsure, say N.
  1086. config ASYNC_RAID6_TEST
  1087. tristate "Self test for hardware accelerated raid6 recovery"
  1088. depends on ASYNC_RAID6_RECOV
  1089. select ASYNC_MEMCPY
  1090. ---help---
  1091. This is a one-shot self test that permutes through the
  1092. recovery of all the possible two disk failure scenarios for a
  1093. N-disk array. Recovery is performed with the asynchronous
  1094. raid6 recovery routines, and will optionally use an offload
  1095. engine if one is available.
  1096. If unsure, say N.
  1097. config PANIC_ON_DATA_CORRUPTION
  1098. bool "Cause a Kernel Panic When Data Corruption is detected"
  1099. help
  1100. Select this option to upgrade warnings for potentially
  1101. recoverable data corruption scenarios to system-halting panics,
  1102. for easier detection and debug.
  1103. source "samples/Kconfig"
  1104. source "lib/Kconfig.kgdb"
  1105. source "lib/Kconfig.kmemcheck"
  1106. config TEST_KSTRTOX
  1107. tristate "Test kstrto*() family of functions at runtime"
  1108. config TEST_HASH
  1109. tristate "Perform selftest on hash functions"
  1110. default n
  1111. help
  1112. Enable this option to test the kernel's siphash (<linux/siphash.h>)
  1113. hash functions on boot (or module load).
  1114. This is intended to help people writing architecture-specific
  1115. optimized versions. If unsure, say N.