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