Kconfig.debug 45 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035103610371038103910401041104210431044104510461047104810491050105110521053105410551056105710581059106010611062106310641065106610671068106910701071107210731074107510761077107810791080108110821083108410851086108710881089109010911092109310941095109610971098109911001101110211031104110511061107110811091110111111121113111411151116111711181119112011211122112311241125112611271128112911301131113211331134113511361137113811391140114111421143114411451146114711481149115011511152115311541155115611571158115911601161116211631164116511661167116811691170117111721173117411751176117711781179118011811182118311841185118611871188118911901191119211931194119511961197119811991200120112021203120412051206120712081209121012111212121312141215121612171218121912201221122212231224122512261227122812291230123112321233123412351236123712381239124012411242124312441245124612471248124912501251125212531254125512561257125812591260126112621263126412651266126712681269127012711272127312741275127612771278127912801281128212831284128512861287128812891290129112921293129412951296129712981299130013011302130313041305130613071308
  1. config PRINTK_TIME
  2. bool "Show timing information on printks"
  3. depends on PRINTK
  4. help
  5. Selecting this option causes time stamps of the printk()
  6. messages to be added to the output of the syslog() system
  7. call and at the console.
  8. The timestamp is always recorded internally, and exported
  9. to /dev/kmsg. This flag just specifies if the timestamp should
  10. be included, not that the timestamp is recorded.
  11. The behavior is also controlled by the kernel command line
  12. parameter printk.time=1. See Documentation/kernel-parameters.txt
  13. config DEFAULT_MESSAGE_LOGLEVEL
  14. int "Default message log level (1-7)"
  15. range 1 7
  16. default "4"
  17. help
  18. Default log level for printk statements with no specified priority.
  19. This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
  20. that are auditing their logs closely may want to set it to a lower
  21. priority.
  22. config ENABLE_WARN_DEPRECATED
  23. bool "Enable __deprecated logic"
  24. default y
  25. help
  26. Enable the __deprecated logic in the kernel build.
  27. Disable this to suppress the "warning: 'foo' is deprecated
  28. (declared at kernel/power/somefile.c:1234)" messages.
  29. config ENABLE_MUST_CHECK
  30. bool "Enable __must_check logic"
  31. default y
  32. help
  33. Enable the __must_check logic in the kernel build. Disable this to
  34. suppress the "warning: ignoring return value of 'foo', declared with
  35. attribute warn_unused_result" messages.
  36. config FRAME_WARN
  37. int "Warn for stack frames larger than (needs gcc 4.4)"
  38. range 0 8192
  39. default 1024 if !64BIT
  40. default 2048 if 64BIT
  41. help
  42. Tell gcc to warn at build time for stack frames larger than this.
  43. Setting this too low will cause a lot of warnings.
  44. Setting it to 0 disables the warning.
  45. Requires gcc 4.4
  46. config MAGIC_SYSRQ
  47. bool "Magic SysRq key"
  48. depends on !UML
  49. help
  50. If you say Y here, you will have some control over the system even
  51. if the system crashes for example during kernel debugging (e.g., you
  52. will be able to flush the buffer cache to disk, reboot the system
  53. immediately or dump some status information). This is accomplished
  54. by pressing various keys while holding SysRq (Alt+PrintScreen). It
  55. also works on a serial console (on PC hardware at least), if you
  56. send a BREAK and then within 5 seconds a command keypress. The
  57. keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
  58. unless you really know what this hack does.
  59. config STRIP_ASM_SYMS
  60. bool "Strip assembler-generated symbols during link"
  61. default n
  62. help
  63. Strip internal assembler-generated symbols during a link (symbols
  64. that look like '.Lxxx') so they don't pollute the output of
  65. get_wchan() and suchlike.
  66. config UNUSED_SYMBOLS
  67. bool "Enable unused/obsolete exported symbols"
  68. default y if X86
  69. help
  70. Unused but exported symbols make the kernel needlessly bigger. For
  71. that reason most of these unused exports will soon be removed. This
  72. option is provided temporarily to provide a transition period in case
  73. some external kernel module needs one of these symbols anyway. If you
  74. encounter such a case in your module, consider if you are actually
  75. using the right API. (rationale: since nobody in the kernel is using
  76. this in a module, there is a pretty good chance it's actually the
  77. wrong interface to use). If you really need the symbol, please send a
  78. mail to the linux kernel mailing list mentioning the symbol and why
  79. you really need it, and what the merge plan to the mainline kernel for
  80. your module is.
  81. config DEBUG_FS
  82. bool "Debug Filesystem"
  83. help
  84. debugfs is a virtual file system that kernel developers use to put
  85. debugging files into. Enable this option to be able to read and
  86. write to these files.
  87. For detailed documentation on the debugfs API, see
  88. Documentation/DocBook/filesystems.
  89. If unsure, say N.
  90. config HEADERS_CHECK
  91. bool "Run 'make headers_check' when building vmlinux"
  92. depends on !UML
  93. help
  94. This option will extract the user-visible kernel headers whenever
  95. building the kernel, and will run basic sanity checks on them to
  96. ensure that exported files do not attempt to include files which
  97. were not exported, etc.
  98. If you're making modifications to header files which are
  99. relevant for userspace, say 'Y', and check the headers
  100. exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
  101. your build tree), to make sure they're suitable.
  102. config DEBUG_SECTION_MISMATCH
  103. bool "Enable full Section mismatch analysis"
  104. help
  105. The section mismatch analysis checks if there are illegal
  106. references from one section to another section.
  107. During linktime or runtime, some sections are dropped;
  108. any use of code/data previously in these sections would
  109. most likely result in an oops.
  110. In the code, functions and variables are annotated with
  111. __init, __devinit, etc. (see the full list in include/linux/init.h),
  112. which results in the code/data being placed in specific sections.
  113. The section mismatch analysis is always performed after a full
  114. kernel build, and enabling this option causes the following
  115. additional steps to occur:
  116. - Add the option -fno-inline-functions-called-once to gcc commands.
  117. When inlining a function annotated with __init in a non-init
  118. function, we would lose the section information and thus
  119. the analysis would not catch the illegal reference.
  120. This option tells gcc to inline less (but it does result in
  121. a larger kernel).
  122. - Run the section mismatch analysis for each module/built-in.o file.
  123. When we run the section mismatch analysis on vmlinux.o, we
  124. lose valueble information about where the mismatch was
  125. introduced.
  126. Running the analysis for each module/built-in.o file
  127. tells where the mismatch happens much closer to the
  128. source. The drawback is that the same mismatch is
  129. reported at least twice.
  130. - Enable verbose reporting from modpost in order to help resolve
  131. the section mismatches that are reported.
  132. config DEBUG_KERNEL
  133. bool "Kernel debugging"
  134. help
  135. Say Y here if you are developing drivers or trying to debug and
  136. identify kernel problems.
  137. config DEBUG_SHIRQ
  138. bool "Debug shared IRQ handlers"
  139. depends on DEBUG_KERNEL && GENERIC_HARDIRQS
  140. help
  141. Enable this to generate a spurious interrupt as soon as a shared
  142. interrupt handler is registered, and just before one is deregistered.
  143. Drivers ought to be able to handle interrupts coming in at those
  144. points; some don't and need to be caught.
  145. config LOCKUP_DETECTOR
  146. bool "Detect Hard and Soft Lockups"
  147. depends on DEBUG_KERNEL && !S390
  148. help
  149. Say Y here to enable the kernel to act as a watchdog to detect
  150. hard and soft lockups.
  151. Softlockups are bugs that cause the kernel to loop in kernel
  152. mode for more than 20 seconds, without giving other tasks a
  153. chance to run. The current stack trace is displayed upon
  154. detection and the system will stay locked up.
  155. Hardlockups are bugs that cause the CPU to loop in kernel mode
  156. for more than 10 seconds, without letting other interrupts have a
  157. chance to run. The current stack trace is displayed upon detection
  158. and the system will stay locked up.
  159. The overhead should be minimal. A periodic hrtimer runs to
  160. generate interrupts and kick the watchdog task every 4 seconds.
  161. An NMI is generated every 10 seconds or so to check for hardlockups.
  162. The frequency of hrtimer and NMI events and the soft and hard lockup
  163. thresholds can be controlled through the sysctl watchdog_thresh.
  164. config HARDLOCKUP_DETECTOR
  165. def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI && \
  166. !HAVE_NMI_WATCHDOG
  167. config BOOTPARAM_HARDLOCKUP_PANIC
  168. bool "Panic (Reboot) On Hard Lockups"
  169. depends on LOCKUP_DETECTOR
  170. help
  171. Say Y here to enable the kernel to panic on "hard lockups",
  172. which are bugs that cause the kernel to loop in kernel
  173. mode with interrupts disabled for more than 10 seconds (configurable
  174. using the watchdog_thresh sysctl).
  175. Say N if unsure.
  176. config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
  177. int
  178. depends on LOCKUP_DETECTOR
  179. range 0 1
  180. default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
  181. default 1 if BOOTPARAM_HARDLOCKUP_PANIC
  182. config BOOTPARAM_SOFTLOCKUP_PANIC
  183. bool "Panic (Reboot) On Soft Lockups"
  184. depends on LOCKUP_DETECTOR
  185. help
  186. Say Y here to enable the kernel to panic on "soft lockups",
  187. which are bugs that cause the kernel to loop in kernel
  188. mode for more than 20 seconds (configurable using the watchdog_thresh
  189. sysctl), without giving other tasks a chance to run.
  190. The panic can be used in combination with panic_timeout,
  191. to cause the system to reboot automatically after a
  192. lockup has been detected. This feature is useful for
  193. high-availability systems that have uptime guarantees and
  194. where a lockup must be resolved ASAP.
  195. Say N if unsure.
  196. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  197. int
  198. depends on LOCKUP_DETECTOR
  199. range 0 1
  200. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  201. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  202. config DETECT_HUNG_TASK
  203. bool "Detect Hung Tasks"
  204. depends on DEBUG_KERNEL
  205. default LOCKUP_DETECTOR
  206. help
  207. Say Y here to enable the kernel to detect "hung tasks",
  208. which are bugs that cause the task to be stuck in
  209. uninterruptible "D" state indefinitiley.
  210. When a hung task is detected, the kernel will print the
  211. current stack trace (which you should report), but the
  212. task will stay in uninterruptible state. If lockdep is
  213. enabled then all held locks will also be reported. This
  214. feature has negligible overhead.
  215. config DEFAULT_HUNG_TASK_TIMEOUT
  216. int "Default timeout for hung task detection (in seconds)"
  217. depends on DETECT_HUNG_TASK
  218. default 120
  219. help
  220. This option controls the default timeout (in seconds) used
  221. to determine when a task has become non-responsive and should
  222. be considered hung.
  223. It can be adjusted at runtime via the kernel.hung_task_timeout_secs
  224. sysctl or by writing a value to
  225. /proc/sys/kernel/hung_task_timeout_secs.
  226. A timeout of 0 disables the check. The default is two minutes.
  227. Keeping the default should be fine in most cases.
  228. config BOOTPARAM_HUNG_TASK_PANIC
  229. bool "Panic (Reboot) On Hung Tasks"
  230. depends on DETECT_HUNG_TASK
  231. help
  232. Say Y here to enable the kernel to panic on "hung tasks",
  233. which are bugs that cause the kernel to leave a task stuck
  234. in uninterruptible "D" state.
  235. The panic can be used in combination with panic_timeout,
  236. to cause the system to reboot automatically after a
  237. hung task has been detected. This feature is useful for
  238. high-availability systems that have uptime guarantees and
  239. where a hung tasks must be resolved ASAP.
  240. Say N if unsure.
  241. config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  242. int
  243. depends on DETECT_HUNG_TASK
  244. range 0 1
  245. default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  246. default 1 if BOOTPARAM_HUNG_TASK_PANIC
  247. config SCHED_DEBUG
  248. bool "Collect scheduler debugging info"
  249. depends on DEBUG_KERNEL && PROC_FS
  250. default y
  251. help
  252. If you say Y here, the /proc/sched_debug file will be provided
  253. that can help debug the scheduler. The runtime overhead of this
  254. option is minimal.
  255. config SCHEDSTATS
  256. bool "Collect scheduler statistics"
  257. depends on DEBUG_KERNEL && PROC_FS
  258. help
  259. If you say Y here, additional code will be inserted into the
  260. scheduler and related routines to collect statistics about
  261. scheduler behavior and provide them in /proc/schedstat. These
  262. stats may be useful for both tuning and debugging the scheduler
  263. If you aren't debugging the scheduler or trying to tune a specific
  264. application, you can say N to avoid the very slight overhead
  265. this adds.
  266. config TIMER_STATS
  267. bool "Collect kernel timers statistics"
  268. depends on DEBUG_KERNEL && PROC_FS
  269. help
  270. If you say Y here, additional code will be inserted into the
  271. timer routines to collect statistics about kernel timers being
  272. reprogrammed. The statistics can be read from /proc/timer_stats.
  273. The statistics collection is started by writing 1 to /proc/timer_stats,
  274. writing 0 stops it. This feature is useful to collect information
  275. about timer usage patterns in kernel and userspace. This feature
  276. is lightweight if enabled in the kernel config but not activated
  277. (it defaults to deactivated on bootup and will only be activated
  278. if some application like powertop activates it explicitly).
  279. config DEBUG_OBJECTS
  280. bool "Debug object operations"
  281. depends on DEBUG_KERNEL
  282. help
  283. If you say Y here, additional code will be inserted into the
  284. kernel to track the life time of various objects and validate
  285. the operations on those objects.
  286. config DEBUG_OBJECTS_SELFTEST
  287. bool "Debug objects selftest"
  288. depends on DEBUG_OBJECTS
  289. help
  290. This enables the selftest of the object debug code.
  291. config DEBUG_OBJECTS_FREE
  292. bool "Debug objects in freed memory"
  293. depends on DEBUG_OBJECTS
  294. help
  295. This enables checks whether a k/v free operation frees an area
  296. which contains an object which has not been deactivated
  297. properly. This can make kmalloc/kfree-intensive workloads
  298. much slower.
  299. config DEBUG_OBJECTS_TIMERS
  300. bool "Debug timer objects"
  301. depends on DEBUG_OBJECTS
  302. help
  303. If you say Y here, additional code will be inserted into the
  304. timer routines to track the life time of timer objects and
  305. validate the timer operations.
  306. config DEBUG_OBJECTS_WORK
  307. bool "Debug work objects"
  308. depends on DEBUG_OBJECTS
  309. help
  310. If you say Y here, additional code will be inserted into the
  311. work queue routines to track the life time of work objects and
  312. validate the work operations.
  313. config DEBUG_OBJECTS_RCU_HEAD
  314. bool "Debug RCU callbacks objects"
  315. depends on DEBUG_OBJECTS
  316. help
  317. Enable this to turn on debugging of RCU list heads (call_rcu() usage).
  318. config DEBUG_OBJECTS_PERCPU_COUNTER
  319. bool "Debug percpu counter objects"
  320. depends on DEBUG_OBJECTS
  321. help
  322. If you say Y here, additional code will be inserted into the
  323. percpu counter routines to track the life time of percpu counter
  324. objects and validate the percpu counter operations.
  325. config DEBUG_OBJECTS_ENABLE_DEFAULT
  326. int "debug_objects bootup default value (0-1)"
  327. range 0 1
  328. default "1"
  329. depends on DEBUG_OBJECTS
  330. help
  331. Debug objects boot parameter default value
  332. config DEBUG_SLAB
  333. bool "Debug slab memory allocations"
  334. depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
  335. help
  336. Say Y here to have the kernel do limited verification on memory
  337. allocation as well as poisoning memory on free to catch use of freed
  338. memory. This can make kmalloc/kfree-intensive workloads much slower.
  339. config DEBUG_SLAB_LEAK
  340. bool "Memory leak debugging"
  341. depends on DEBUG_SLAB
  342. config SLUB_DEBUG_ON
  343. bool "SLUB debugging on by default"
  344. depends on SLUB && SLUB_DEBUG && !KMEMCHECK
  345. default n
  346. help
  347. Boot with debugging on by default. SLUB boots by default with
  348. the runtime debug capabilities switched off. Enabling this is
  349. equivalent to specifying the "slub_debug" parameter on boot.
  350. There is no support for more fine grained debug control like
  351. possible with slub_debug=xxx. SLUB debugging may be switched
  352. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  353. "slub_debug=-".
  354. config SLUB_STATS
  355. default n
  356. bool "Enable SLUB performance statistics"
  357. depends on SLUB && SYSFS
  358. help
  359. SLUB statistics are useful to debug SLUBs allocation behavior in
  360. order find ways to optimize the allocator. This should never be
  361. enabled for production use since keeping statistics slows down
  362. the allocator by a few percentage points. The slabinfo command
  363. supports the determination of the most active slabs to figure
  364. out which slabs are relevant to a particular load.
  365. Try running: slabinfo -DA
  366. config DEBUG_KMEMLEAK
  367. bool "Kernel memory leak detector"
  368. depends on DEBUG_KERNEL && EXPERIMENTAL && \
  369. (X86 || ARM || PPC || MIPS || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
  370. select DEBUG_FS
  371. select STACKTRACE if STACKTRACE_SUPPORT
  372. select KALLSYMS
  373. select CRC32
  374. help
  375. Say Y here if you want to enable the memory leak
  376. detector. The memory allocation/freeing is traced in a way
  377. similar to the Boehm's conservative garbage collector, the
  378. difference being that the orphan objects are not freed but
  379. only shown in /sys/kernel/debug/kmemleak. Enabling this
  380. feature will introduce an overhead to memory
  381. allocations. See Documentation/kmemleak.txt for more
  382. details.
  383. Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  384. of finding leaks due to the slab objects poisoning.
  385. In order to access the kmemleak file, debugfs needs to be
  386. mounted (usually at /sys/kernel/debug).
  387. config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
  388. int "Maximum kmemleak early log entries"
  389. depends on DEBUG_KMEMLEAK
  390. range 200 40000
  391. default 400
  392. help
  393. Kmemleak must track all the memory allocations to avoid
  394. reporting false positives. Since memory may be allocated or
  395. freed before kmemleak is initialised, an early log buffer is
  396. used to store these actions. If kmemleak reports "early log
  397. buffer exceeded", please increase this value.
  398. config DEBUG_KMEMLEAK_TEST
  399. tristate "Simple test for the kernel memory leak detector"
  400. depends on DEBUG_KMEMLEAK && m
  401. help
  402. This option enables a module that explicitly leaks memory.
  403. If unsure, say N.
  404. config DEBUG_KMEMLEAK_DEFAULT_OFF
  405. bool "Default kmemleak to off"
  406. depends on DEBUG_KMEMLEAK
  407. help
  408. Say Y here to disable kmemleak by default. It can then be enabled
  409. on the command line via kmemleak=on.
  410. config DEBUG_PREEMPT
  411. bool "Debug preemptible kernel"
  412. depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
  413. default y
  414. help
  415. If you say Y here then the kernel will use a debug variant of the
  416. commonly used smp_processor_id() function and will print warnings
  417. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  418. will detect preemption count underflows.
  419. config DEBUG_RT_MUTEXES
  420. bool "RT Mutex debugging, deadlock detection"
  421. depends on DEBUG_KERNEL && RT_MUTEXES
  422. help
  423. This allows rt mutex semantics violations and rt mutex related
  424. deadlocks (lockups) to be detected and reported automatically.
  425. config DEBUG_PI_LIST
  426. bool
  427. default y
  428. depends on DEBUG_RT_MUTEXES
  429. config RT_MUTEX_TESTER
  430. bool "Built-in scriptable tester for rt-mutexes"
  431. depends on DEBUG_KERNEL && RT_MUTEXES
  432. help
  433. This option enables a rt-mutex tester.
  434. config DEBUG_SPINLOCK
  435. bool "Spinlock and rw-lock debugging: basic checks"
  436. depends on DEBUG_KERNEL
  437. select UNINLINE_SPIN_UNLOCK
  438. help
  439. Say Y here and build SMP to catch missing spinlock initialization
  440. and certain other kinds of spinlock errors commonly made. This is
  441. best used in conjunction with the NMI watchdog so that spinlock
  442. deadlocks are also debuggable.
  443. config DEBUG_MUTEXES
  444. bool "Mutex debugging: basic checks"
  445. depends on DEBUG_KERNEL
  446. help
  447. This feature allows mutex semantics violations to be detected and
  448. reported.
  449. config DEBUG_LOCK_ALLOC
  450. bool "Lock debugging: detect incorrect freeing of live locks"
  451. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  452. select DEBUG_SPINLOCK
  453. select DEBUG_MUTEXES
  454. select LOCKDEP
  455. help
  456. This feature will check whether any held lock (spinlock, rwlock,
  457. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  458. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  459. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  460. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  461. held during task exit.
  462. config PROVE_LOCKING
  463. bool "Lock debugging: prove locking correctness"
  464. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  465. select LOCKDEP
  466. select DEBUG_SPINLOCK
  467. select DEBUG_MUTEXES
  468. select DEBUG_LOCK_ALLOC
  469. select TRACE_IRQFLAGS
  470. default n
  471. help
  472. This feature enables the kernel to prove that all locking
  473. that occurs in the kernel runtime is mathematically
  474. correct: that under no circumstance could an arbitrary (and
  475. not yet triggered) combination of observed locking
  476. sequences (on an arbitrary number of CPUs, running an
  477. arbitrary number of tasks and interrupt contexts) cause a
  478. deadlock.
  479. In short, this feature enables the kernel to report locking
  480. related deadlocks before they actually occur.
  481. The proof does not depend on how hard and complex a
  482. deadlock scenario would be to trigger: how many
  483. participant CPUs, tasks and irq-contexts would be needed
  484. for it to trigger. The proof also does not depend on
  485. timing: if a race and a resulting deadlock is possible
  486. theoretically (no matter how unlikely the race scenario
  487. is), it will be proven so and will immediately be
  488. reported by the kernel (once the event is observed that
  489. makes the deadlock theoretically possible).
  490. If a deadlock is impossible (i.e. the locking rules, as
  491. observed by the kernel, are mathematically correct), the
  492. kernel reports nothing.
  493. NOTE: this feature can also be enabled for rwlocks, mutexes
  494. and rwsems - in which case all dependencies between these
  495. different locking variants are observed and mapped too, and
  496. the proof of observed correctness is also maintained for an
  497. arbitrary combination of these separate locking variants.
  498. For more details, see Documentation/lockdep-design.txt.
  499. config PROVE_RCU
  500. bool "RCU debugging: prove RCU correctness"
  501. depends on PROVE_LOCKING
  502. default n
  503. help
  504. This feature enables lockdep extensions that check for correct
  505. use of RCU APIs. This is currently under development. Say Y
  506. if you want to debug RCU usage or help work on the PROVE_RCU
  507. feature.
  508. Say N if you are unsure.
  509. config PROVE_RCU_REPEATEDLY
  510. bool "RCU debugging: don't disable PROVE_RCU on first splat"
  511. depends on PROVE_RCU
  512. default n
  513. help
  514. By itself, PROVE_RCU will disable checking upon issuing the
  515. first warning (or "splat"). This feature prevents such
  516. disabling, allowing multiple RCU-lockdep warnings to be printed
  517. on a single reboot.
  518. Say Y to allow multiple RCU-lockdep warnings per boot.
  519. Say N if you are unsure.
  520. config SPARSE_RCU_POINTER
  521. bool "RCU debugging: sparse-based checks for pointer usage"
  522. default n
  523. help
  524. This feature enables the __rcu sparse annotation for
  525. RCU-protected pointers. This annotation will cause sparse
  526. to flag any non-RCU used of annotated pointers. This can be
  527. helpful when debugging RCU usage. Please note that this feature
  528. is not intended to enforce code cleanliness; it is instead merely
  529. a debugging aid.
  530. Say Y to make sparse flag questionable use of RCU-protected pointers
  531. Say N if you are unsure.
  532. config LOCKDEP
  533. bool
  534. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  535. select STACKTRACE
  536. select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
  537. select KALLSYMS
  538. select KALLSYMS_ALL
  539. config LOCK_STAT
  540. bool "Lock usage statistics"
  541. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  542. select LOCKDEP
  543. select DEBUG_SPINLOCK
  544. select DEBUG_MUTEXES
  545. select DEBUG_LOCK_ALLOC
  546. default n
  547. help
  548. This feature enables tracking lock contention points
  549. For more details, see Documentation/lockstat.txt
  550. This also enables lock events required by "perf lock",
  551. subcommand of perf.
  552. If you want to use "perf lock", you also need to turn on
  553. CONFIG_EVENT_TRACING.
  554. CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
  555. (CONFIG_LOCKDEP defines "acquire" and "release" events.)
  556. config DEBUG_LOCKDEP
  557. bool "Lock dependency engine debugging"
  558. depends on DEBUG_KERNEL && LOCKDEP
  559. help
  560. If you say Y here, the lock dependency engine will do
  561. additional runtime checks to debug itself, at the price
  562. of more runtime overhead.
  563. config TRACE_IRQFLAGS
  564. bool
  565. help
  566. Enables hooks to interrupt enabling and disabling for
  567. either tracing or lock debugging.
  568. config DEBUG_ATOMIC_SLEEP
  569. bool "Sleep inside atomic section checking"
  570. select PREEMPT_COUNT
  571. depends on DEBUG_KERNEL
  572. help
  573. If you say Y here, various routines which may sleep will become very
  574. noisy if they are called inside atomic sections: when a spinlock is
  575. held, inside an rcu read side critical section, inside preempt disabled
  576. sections, inside an interrupt, etc...
  577. config DEBUG_LOCKING_API_SELFTESTS
  578. bool "Locking API boot-time self-tests"
  579. depends on DEBUG_KERNEL
  580. help
  581. Say Y here if you want the kernel to run a short self-test during
  582. bootup. The self-test checks whether common types of locking bugs
  583. are detected by debugging mechanisms or not. (if you disable
  584. lock debugging then those bugs wont be detected of course.)
  585. The following locking APIs are covered: spinlocks, rwlocks,
  586. mutexes and rwsems.
  587. config STACKTRACE
  588. bool
  589. depends on STACKTRACE_SUPPORT
  590. config DEBUG_STACK_USAGE
  591. bool "Stack utilization instrumentation"
  592. depends on DEBUG_KERNEL
  593. help
  594. Enables the display of the minimum amount of free stack which each
  595. task has ever had available in the sysrq-T and sysrq-P debug output.
  596. This option will slow down process creation somewhat.
  597. config DEBUG_KOBJECT
  598. bool "kobject debugging"
  599. depends on DEBUG_KERNEL
  600. help
  601. If you say Y here, some extra kobject debugging messages will be sent
  602. to the syslog.
  603. config DEBUG_HIGHMEM
  604. bool "Highmem debugging"
  605. depends on DEBUG_KERNEL && HIGHMEM
  606. help
  607. This options enables addition error checking for high memory systems.
  608. Disable for production systems.
  609. config DEBUG_BUGVERBOSE
  610. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
  611. depends on BUG
  612. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  613. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 || TILE
  614. default y
  615. help
  616. Say Y here to make BUG() panics output the file name and line number
  617. of the BUG call as well as the EIP and oops trace. This aids
  618. debugging but costs about 70-100K of memory.
  619. config DEBUG_INFO
  620. bool "Compile the kernel with debug info"
  621. depends on DEBUG_KERNEL
  622. help
  623. If you say Y here the resulting kernel image will include
  624. debugging info resulting in a larger kernel image.
  625. This adds debug symbols to the kernel and modules (gcc -g), and
  626. is needed if you intend to use kernel crashdump or binary object
  627. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  628. Say Y here only if you plan to debug the kernel.
  629. If unsure, say N.
  630. config DEBUG_INFO_REDUCED
  631. bool "Reduce debugging information"
  632. depends on DEBUG_INFO
  633. help
  634. If you say Y here gcc is instructed to generate less debugging
  635. information for structure types. This means that tools that
  636. need full debugging information (like kgdb or systemtap) won't
  637. be happy. But if you merely need debugging information to
  638. resolve line numbers there is no loss. Advantage is that
  639. build directory object sizes shrink dramatically over a full
  640. DEBUG_INFO build and compile times are reduced too.
  641. Only works with newer gcc versions.
  642. config DEBUG_VM
  643. bool "Debug VM"
  644. depends on DEBUG_KERNEL
  645. help
  646. Enable this to turn on extended checks in the virtual-memory system
  647. that may impact performance.
  648. If unsure, say N.
  649. config DEBUG_VIRTUAL
  650. bool "Debug VM translations"
  651. depends on DEBUG_KERNEL && X86
  652. help
  653. Enable some costly sanity checks in virtual to page code. This can
  654. catch mistakes with virt_to_page() and friends.
  655. If unsure, say N.
  656. config DEBUG_NOMMU_REGIONS
  657. bool "Debug the global anon/private NOMMU mapping region tree"
  658. depends on DEBUG_KERNEL && !MMU
  659. help
  660. This option causes the global tree of anonymous and private mapping
  661. regions to be regularly checked for invalid topology.
  662. config DEBUG_WRITECOUNT
  663. bool "Debug filesystem writers count"
  664. depends on DEBUG_KERNEL
  665. help
  666. Enable this to catch wrong use of the writers count in struct
  667. vfsmount. This will increase the size of each file struct by
  668. 32 bits.
  669. If unsure, say N.
  670. config DEBUG_MEMORY_INIT
  671. bool "Debug memory initialisation" if EXPERT
  672. default !EXPERT
  673. help
  674. Enable this for additional checks during memory initialisation.
  675. The sanity checks verify aspects of the VM such as the memory model
  676. and other information provided by the architecture. Verbose
  677. information will be printed at KERN_DEBUG loglevel depending
  678. on the mminit_loglevel= command-line option.
  679. If unsure, say Y
  680. config DEBUG_LIST
  681. bool "Debug linked list manipulation"
  682. depends on DEBUG_KERNEL
  683. help
  684. Enable this to turn on extended checks in the linked-list
  685. walking routines.
  686. If unsure, say N.
  687. config TEST_LIST_SORT
  688. bool "Linked list sorting test"
  689. depends on DEBUG_KERNEL
  690. help
  691. Enable this to turn on 'list_sort()' function test. This test is
  692. executed only once during system boot, so affects only boot time.
  693. If unsure, say N.
  694. config DEBUG_SG
  695. bool "Debug SG table operations"
  696. depends on DEBUG_KERNEL
  697. help
  698. Enable this to turn on checks on scatter-gather tables. This can
  699. help find problems with drivers that do not properly initialize
  700. their sg tables.
  701. If unsure, say N.
  702. config DEBUG_NOTIFIERS
  703. bool "Debug notifier call chains"
  704. depends on DEBUG_KERNEL
  705. help
  706. Enable this to turn on sanity checking for notifier call chains.
  707. This is most useful for kernel developers to make sure that
  708. modules properly unregister themselves from notifier chains.
  709. This is a relatively cheap check but if you care about maximum
  710. performance, say N.
  711. config DEBUG_CREDENTIALS
  712. bool "Debug credential management"
  713. depends on DEBUG_KERNEL
  714. help
  715. Enable this to turn on some debug checking for credential
  716. management. The additional code keeps track of the number of
  717. pointers from task_structs to any given cred struct, and checks to
  718. see that this number never exceeds the usage count of the cred
  719. struct.
  720. Furthermore, if SELinux is enabled, this also checks that the
  721. security pointer in the cred struct is never seen to be invalid.
  722. If unsure, say N.
  723. #
  724. # Select this config option from the architecture Kconfig, if it
  725. # is preferred to always offer frame pointers as a config
  726. # option on the architecture (regardless of KERNEL_DEBUG):
  727. #
  728. config ARCH_WANT_FRAME_POINTERS
  729. bool
  730. help
  731. config FRAME_POINTER
  732. bool "Compile the kernel with frame pointers"
  733. depends on DEBUG_KERNEL && \
  734. (CRIS || M68K || FRV || UML || \
  735. AVR32 || SUPERH || BLACKFIN || MN10300) || \
  736. ARCH_WANT_FRAME_POINTERS
  737. default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
  738. help
  739. If you say Y here the resulting kernel image will be slightly
  740. larger and slower, but it gives very useful debugging information
  741. in case of kernel bugs. (precise oopses/stacktraces/warnings)
  742. config BOOT_PRINTK_DELAY
  743. bool "Delay each boot printk message by N milliseconds"
  744. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  745. help
  746. This build option allows you to read kernel boot messages
  747. by inserting a short delay after each one. The delay is
  748. specified in milliseconds on the kernel command line,
  749. using "boot_delay=N".
  750. It is likely that you would also need to use "lpj=M" to preset
  751. the "loops per jiffie" value.
  752. See a previous boot log for the "lpj" value to use for your
  753. system, and then set "lpj=M" before setting "boot_delay=N".
  754. NOTE: Using this option may adversely affect SMP systems.
  755. I.e., processors other than the first one may not boot up.
  756. BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
  757. what it believes to be lockup conditions.
  758. config RCU_TORTURE_TEST
  759. tristate "torture tests for RCU"
  760. depends on DEBUG_KERNEL
  761. default n
  762. help
  763. This option provides a kernel module that runs torture tests
  764. on the RCU infrastructure. The kernel module may be built
  765. after the fact on the running kernel to be tested, if desired.
  766. Say Y here if you want RCU torture tests to be built into
  767. the kernel.
  768. Say M if you want the RCU torture tests to build as a module.
  769. Say N if you are unsure.
  770. config RCU_TORTURE_TEST_RUNNABLE
  771. bool "torture tests for RCU runnable by default"
  772. depends on RCU_TORTURE_TEST = y
  773. default n
  774. help
  775. This option provides a way to build the RCU torture tests
  776. directly into the kernel without them starting up at boot
  777. time. You can use /proc/sys/kernel/rcutorture_runnable
  778. to manually override this setting. This /proc file is
  779. available only when the RCU torture tests have been built
  780. into the kernel.
  781. Say Y here if you want the RCU torture tests to start during
  782. boot (you probably don't).
  783. Say N here if you want the RCU torture tests to start only
  784. after being manually enabled via /proc.
  785. config RCU_CPU_STALL_TIMEOUT
  786. int "RCU CPU stall timeout in seconds"
  787. depends on TREE_RCU || TREE_PREEMPT_RCU
  788. range 3 300
  789. default 60
  790. help
  791. If a given RCU grace period extends more than the specified
  792. number of seconds, a CPU stall warning is printed. If the
  793. RCU grace period persists, additional CPU stall warnings are
  794. printed at more widely spaced intervals.
  795. config RCU_CPU_STALL_VERBOSE
  796. bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
  797. depends on TREE_PREEMPT_RCU
  798. default y
  799. help
  800. This option causes RCU to printk detailed per-task information
  801. for any tasks that are stalling the current RCU grace period.
  802. Say N if you are unsure.
  803. Say Y if you want to enable such checks.
  804. config RCU_CPU_STALL_INFO
  805. bool "Print additional diagnostics on RCU CPU stall"
  806. depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
  807. default n
  808. help
  809. For each stalled CPU that is aware of the current RCU grace
  810. period, print out additional per-CPU diagnostic information
  811. regarding scheduling-clock ticks, idle state, and,
  812. for RCU_FAST_NO_HZ kernels, idle-entry state.
  813. Say N if you are unsure.
  814. Say Y if you want to enable such diagnostics.
  815. config RCU_TRACE
  816. bool "Enable tracing for RCU"
  817. depends on DEBUG_KERNEL
  818. help
  819. This option provides tracing in RCU which presents stats
  820. in debugfs for debugging RCU implementation.
  821. Say Y here if you want to enable RCU tracing
  822. Say N if you are unsure.
  823. config KPROBES_SANITY_TEST
  824. bool "Kprobes sanity tests"
  825. depends on DEBUG_KERNEL
  826. depends on KPROBES
  827. default n
  828. help
  829. This option provides for testing basic kprobes functionality on
  830. boot. A sample kprobe, jprobe and kretprobe are inserted and
  831. verified for functionality.
  832. Say N if you are unsure.
  833. config BACKTRACE_SELF_TEST
  834. tristate "Self test for the backtrace code"
  835. depends on DEBUG_KERNEL
  836. default n
  837. help
  838. This option provides a kernel module that can be used to test
  839. the kernel stack backtrace code. This option is not useful
  840. for distributions or general kernels, but only for kernel
  841. developers working on architecture code.
  842. Note that if you want to also test saved backtraces, you will
  843. have to enable STACKTRACE as well.
  844. Say N if you are unsure.
  845. config DEBUG_BLOCK_EXT_DEVT
  846. bool "Force extended block device numbers and spread them"
  847. depends on DEBUG_KERNEL
  848. depends on BLOCK
  849. default n
  850. help
  851. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  852. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  853. YOU ARE DOING. Distros, please enable this and fix whatever
  854. is broken.
  855. Conventionally, block device numbers are allocated from
  856. predetermined contiguous area. However, extended block area
  857. may introduce non-contiguous block device numbers. This
  858. option forces most block device numbers to be allocated from
  859. the extended space and spreads them to discover kernel or
  860. userland code paths which assume predetermined contiguous
  861. device number allocation.
  862. Note that turning on this debug option shuffles all the
  863. device numbers for all IDE and SCSI devices including libata
  864. ones, so root partition specified using device number
  865. directly (via rdev or root=MAJ:MIN) won't work anymore.
  866. Textual device names (root=/dev/sdXn) will continue to work.
  867. Say N if you are unsure.
  868. config DEBUG_FORCE_WEAK_PER_CPU
  869. bool "Force weak per-cpu definitions"
  870. depends on DEBUG_KERNEL
  871. help
  872. s390 and alpha require percpu variables in modules to be
  873. defined weak to work around addressing range issue which
  874. puts the following two restrictions on percpu variable
  875. definitions.
  876. 1. percpu symbols must be unique whether static or not
  877. 2. percpu variables can't be defined inside a function
  878. To ensure that generic code follows the above rules, this
  879. option forces all percpu variables to be defined as weak.
  880. config DEBUG_PER_CPU_MAPS
  881. bool "Debug access to per_cpu maps"
  882. depends on DEBUG_KERNEL
  883. depends on SMP
  884. help
  885. Say Y to verify that the per_cpu map being accessed has
  886. been set up. This adds a fair amount of code to kernel memory
  887. and decreases performance.
  888. Say N if unsure.
  889. config LKDTM
  890. tristate "Linux Kernel Dump Test Tool Module"
  891. depends on DEBUG_FS
  892. depends on BLOCK
  893. default n
  894. help
  895. This module enables testing of the different dumping mechanisms by
  896. inducing system failures at predefined crash points.
  897. If you don't need it: say N
  898. Choose M here to compile this code as a module. The module will be
  899. called lkdtm.
  900. Documentation on how to use the module can be found in
  901. Documentation/fault-injection/provoke-crashes.txt
  902. config CPU_NOTIFIER_ERROR_INJECT
  903. tristate "CPU notifier error injection module"
  904. depends on HOTPLUG_CPU && DEBUG_KERNEL
  905. help
  906. This option provides a kernel module that can be used to test
  907. the error handling of the cpu notifiers
  908. To compile this code as a module, choose M here: the module will
  909. be called cpu-notifier-error-inject.
  910. If unsure, say N.
  911. config FAULT_INJECTION
  912. bool "Fault-injection framework"
  913. depends on DEBUG_KERNEL
  914. help
  915. Provide fault-injection framework.
  916. For more details, see Documentation/fault-injection/.
  917. config FAILSLAB
  918. bool "Fault-injection capability for kmalloc"
  919. depends on FAULT_INJECTION
  920. depends on SLAB || SLUB
  921. help
  922. Provide fault-injection capability for kmalloc.
  923. config FAIL_PAGE_ALLOC
  924. bool "Fault-injection capabilitiy for alloc_pages()"
  925. depends on FAULT_INJECTION
  926. help
  927. Provide fault-injection capability for alloc_pages().
  928. config FAIL_MAKE_REQUEST
  929. bool "Fault-injection capability for disk IO"
  930. depends on FAULT_INJECTION && BLOCK
  931. help
  932. Provide fault-injection capability for disk IO.
  933. config FAIL_IO_TIMEOUT
  934. bool "Fault-injection capability for faking disk interrupts"
  935. depends on FAULT_INJECTION && BLOCK
  936. help
  937. Provide fault-injection capability on end IO handling. This
  938. will make the block layer "forget" an interrupt as configured,
  939. thus exercising the error handling.
  940. Only works with drivers that use the generic timeout handling,
  941. for others it wont do anything.
  942. config FAIL_MMC_REQUEST
  943. bool "Fault-injection capability for MMC IO"
  944. select DEBUG_FS
  945. depends on FAULT_INJECTION && MMC
  946. help
  947. Provide fault-injection capability for MMC IO.
  948. This will make the mmc core return data errors. This is
  949. useful to test the error handling in the mmc block device
  950. and to test how the mmc host driver handles retries from
  951. the block device.
  952. config FAULT_INJECTION_DEBUG_FS
  953. bool "Debugfs entries for fault-injection capabilities"
  954. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  955. help
  956. Enable configuration of fault-injection capabilities via debugfs.
  957. config FAULT_INJECTION_STACKTRACE_FILTER
  958. bool "stacktrace filter for fault-injection capabilities"
  959. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  960. depends on !X86_64
  961. select STACKTRACE
  962. select FRAME_POINTER if !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  963. help
  964. Provide stacktrace filter for fault-injection capabilities
  965. config LATENCYTOP
  966. bool "Latency measuring infrastructure"
  967. depends on HAVE_LATENCYTOP_SUPPORT
  968. depends on DEBUG_KERNEL
  969. depends on STACKTRACE_SUPPORT
  970. depends on PROC_FS
  971. select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
  972. select KALLSYMS
  973. select KALLSYMS_ALL
  974. select STACKTRACE
  975. select SCHEDSTATS
  976. select SCHED_DEBUG
  977. help
  978. Enable this option if you want to use the LatencyTOP tool
  979. to find out which userspace is blocking on what kernel operations.
  980. source mm/Kconfig.debug
  981. source kernel/trace/Kconfig
  982. config PROVIDE_OHCI1394_DMA_INIT
  983. bool "Remote debugging over FireWire early on boot"
  984. depends on PCI && X86
  985. help
  986. If you want to debug problems which hang or crash the kernel early
  987. on boot and the crashing machine has a FireWire port, you can use
  988. this feature to remotely access the memory of the crashed machine
  989. over FireWire. This employs remote DMA as part of the OHCI1394
  990. specification which is now the standard for FireWire controllers.
  991. With remote DMA, you can monitor the printk buffer remotely using
  992. firescope and access all memory below 4GB using fireproxy from gdb.
  993. Even controlling a kernel debugger is possible using remote DMA.
  994. Usage:
  995. If ohci1394_dma=early is used as boot parameter, it will initialize
  996. all OHCI1394 controllers which are found in the PCI config space.
  997. As all changes to the FireWire bus such as enabling and disabling
  998. devices cause a bus reset and thereby disable remote DMA for all
  999. devices, be sure to have the cable plugged and FireWire enabled on
  1000. the debugging host before booting the debug target for debugging.
  1001. This code (~1k) is freed after boot. By then, the firewire stack
  1002. in charge of the OHCI-1394 controllers should be used instead.
  1003. See Documentation/debugging-via-ohci1394.txt for more information.
  1004. config FIREWIRE_OHCI_REMOTE_DMA
  1005. bool "Remote debugging over FireWire with firewire-ohci"
  1006. depends on FIREWIRE_OHCI
  1007. help
  1008. This option lets you use the FireWire bus for remote debugging
  1009. with help of the firewire-ohci driver. It enables unfiltered
  1010. remote DMA in firewire-ohci.
  1011. See Documentation/debugging-via-ohci1394.txt for more information.
  1012. If unsure, say N.
  1013. config BUILD_DOCSRC
  1014. bool "Build targets in Documentation/ tree"
  1015. depends on HEADERS_CHECK
  1016. help
  1017. This option attempts to build objects from the source files in the
  1018. kernel Documentation/ tree.
  1019. Say N if you are unsure.
  1020. config DYNAMIC_DEBUG
  1021. bool "Enable dynamic printk() support"
  1022. default n
  1023. depends on PRINTK
  1024. depends on DEBUG_FS
  1025. help
  1026. Compiles debug level messages into the kernel, which would not
  1027. otherwise be available at runtime. These messages can then be
  1028. enabled/disabled based on various levels of scope - per source file,
  1029. function, module, format string, and line number. This mechanism
  1030. implicitly compiles in all pr_debug() and dev_dbg() calls, which
  1031. enlarges the kernel text size by about 2%.
  1032. If a source file is compiled with DEBUG flag set, any
  1033. pr_debug() calls in it are enabled by default, but can be
  1034. disabled at runtime as below. Note that DEBUG flag is
  1035. turned on by many CONFIG_*DEBUG* options.
  1036. Usage:
  1037. Dynamic debugging is controlled via the 'dynamic_debug/control' file,
  1038. which is contained in the 'debugfs' filesystem. Thus, the debugfs
  1039. filesystem must first be mounted before making use of this feature.
  1040. We refer the control file as: <debugfs>/dynamic_debug/control. This
  1041. file contains a list of the debug statements that can be enabled. The
  1042. format for each line of the file is:
  1043. filename:lineno [module]function flags format
  1044. filename : source file of the debug statement
  1045. lineno : line number of the debug statement
  1046. module : module that contains the debug statement
  1047. function : function that contains the debug statement
  1048. flags : '=p' means the line is turned 'on' for printing
  1049. format : the format used for the debug statement
  1050. From a live system:
  1051. nullarbor:~ # cat <debugfs>/dynamic_debug/control
  1052. # filename:lineno [module]function flags format
  1053. fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
  1054. fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
  1055. fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
  1056. Example usage:
  1057. // enable the message at line 1603 of file svcsock.c
  1058. nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
  1059. <debugfs>/dynamic_debug/control
  1060. // enable all the messages in file svcsock.c
  1061. nullarbor:~ # echo -n 'file svcsock.c +p' >
  1062. <debugfs>/dynamic_debug/control
  1063. // enable all the messages in the NFS server module
  1064. nullarbor:~ # echo -n 'module nfsd +p' >
  1065. <debugfs>/dynamic_debug/control
  1066. // enable all 12 messages in the function svc_process()
  1067. nullarbor:~ # echo -n 'func svc_process +p' >
  1068. <debugfs>/dynamic_debug/control
  1069. // disable all 12 messages in the function svc_process()
  1070. nullarbor:~ # echo -n 'func svc_process -p' >
  1071. <debugfs>/dynamic_debug/control
  1072. See Documentation/dynamic-debug-howto.txt for additional information.
  1073. config DMA_API_DEBUG
  1074. bool "Enable debugging of DMA-API usage"
  1075. depends on HAVE_DMA_API_DEBUG
  1076. help
  1077. Enable this option to debug the use of the DMA API by device drivers.
  1078. With this option you will be able to detect common bugs in device
  1079. drivers like double-freeing of DMA mappings or freeing mappings that
  1080. were never allocated.
  1081. This option causes a performance degredation. Use only if you want
  1082. to debug device drivers. If unsure, say N.
  1083. config ATOMIC64_SELFTEST
  1084. bool "Perform an atomic64_t self-test at boot"
  1085. help
  1086. Enable this option to test the atomic64_t functions at boot.
  1087. If unsure, say N.
  1088. config ASYNC_RAID6_TEST
  1089. tristate "Self test for hardware accelerated raid6 recovery"
  1090. depends on ASYNC_RAID6_RECOV
  1091. select ASYNC_MEMCPY
  1092. ---help---
  1093. This is a one-shot self test that permutes through the
  1094. recovery of all the possible two disk failure scenarios for a
  1095. N-disk array. Recovery is performed with the asynchronous
  1096. raid6 recovery routines, and will optionally use an offload
  1097. engine if one is available.
  1098. If unsure, say N.
  1099. source "samples/Kconfig"
  1100. source "lib/Kconfig.kgdb"
  1101. source "lib/Kconfig.kmemcheck"
  1102. config TEST_KSTRTOX
  1103. tristate "Test kstrto*() family of functions at runtime"