Kconfig.debug 30 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885
  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.
  10. config ENABLE_WARN_DEPRECATED
  11. bool "Enable __deprecated logic"
  12. default y
  13. help
  14. Enable the __deprecated logic in the kernel build.
  15. Disable this to suppress the "warning: 'foo' is deprecated
  16. (declared at kernel/power/somefile.c:1234)" messages.
  17. config ENABLE_MUST_CHECK
  18. bool "Enable __must_check logic"
  19. default y
  20. help
  21. Enable the __must_check logic in the kernel build. Disable this to
  22. suppress the "warning: ignoring return value of 'foo', declared with
  23. attribute warn_unused_result" messages.
  24. config FRAME_WARN
  25. int "Warn for stack frames larger than (needs gcc 4.4)"
  26. range 0 8192
  27. default 1024 if !64BIT
  28. default 2048 if 64BIT
  29. help
  30. Tell gcc to warn at build time for stack frames larger than this.
  31. Setting this too low will cause a lot of warnings.
  32. Setting it to 0 disables the warning.
  33. Requires gcc 4.4
  34. config MAGIC_SYSRQ
  35. bool "Magic SysRq key"
  36. depends on !UML
  37. help
  38. If you say Y here, you will have some control over the system even
  39. if the system crashes for example during kernel debugging (e.g., you
  40. will be able to flush the buffer cache to disk, reboot the system
  41. immediately or dump some status information). This is accomplished
  42. by pressing various keys while holding SysRq (Alt+PrintScreen). It
  43. also works on a serial console (on PC hardware at least), if you
  44. send a BREAK and then within 5 seconds a command keypress. The
  45. keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
  46. unless you really know what this hack does.
  47. config UNUSED_SYMBOLS
  48. bool "Enable unused/obsolete exported symbols"
  49. default y if X86
  50. help
  51. Unused but exported symbols make the kernel needlessly bigger. For
  52. that reason most of these unused exports will soon be removed. This
  53. option is provided temporarily to provide a transition period in case
  54. some external kernel module needs one of these symbols anyway. If you
  55. encounter such a case in your module, consider if you are actually
  56. using the right API. (rationale: since nobody in the kernel is using
  57. this in a module, there is a pretty good chance it's actually the
  58. wrong interface to use). If you really need the symbol, please send a
  59. mail to the linux kernel mailing list mentioning the symbol and why
  60. you really need it, and what the merge plan to the mainline kernel for
  61. your module is.
  62. config DEBUG_FS
  63. bool "Debug Filesystem"
  64. depends on SYSFS
  65. help
  66. debugfs is a virtual file system that kernel developers use to put
  67. debugging files into. Enable this option to be able to read and
  68. write to these files.
  69. For detailed documentation on the debugfs API, see
  70. Documentation/DocBook/filesystems.
  71. If unsure, say N.
  72. config HEADERS_CHECK
  73. bool "Run 'make headers_check' when building vmlinux"
  74. depends on !UML
  75. help
  76. This option will extract the user-visible kernel headers whenever
  77. building the kernel, and will run basic sanity checks on them to
  78. ensure that exported files do not attempt to include files which
  79. were not exported, etc.
  80. If you're making modifications to header files which are
  81. relevant for userspace, say 'Y', and check the headers
  82. exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
  83. your build tree), to make sure they're suitable.
  84. config DEBUG_SECTION_MISMATCH
  85. bool "Enable full Section mismatch analysis"
  86. depends on UNDEFINED
  87. # This option is on purpose disabled for now.
  88. # It will be enabled when we are down to a resonable number
  89. # of section mismatch warnings (< 10 for an allyesconfig build)
  90. help
  91. The section mismatch analysis checks if there are illegal
  92. references from one section to another section.
  93. Linux will during link or during runtime drop some sections
  94. and any use of code/data previously in these sections will
  95. most likely result in an oops.
  96. In the code functions and variables are annotated with
  97. __init, __devinit etc. (see full list in include/linux/init.h)
  98. which results in the code/data being placed in specific sections.
  99. The section mismatch analysis is always done after a full
  100. kernel build but enabling this option will in addition
  101. do the following:
  102. - Add the option -fno-inline-functions-called-once to gcc
  103. When inlining a function annotated __init in a non-init
  104. function we would lose the section information and thus
  105. the analysis would not catch the illegal reference.
  106. This option tells gcc to inline less but will also
  107. result in a larger kernel.
  108. - Run the section mismatch analysis for each module/built-in.o
  109. When we run the section mismatch analysis on vmlinux.o we
  110. lose valueble information about where the mismatch was
  111. introduced.
  112. Running the analysis for each module/built-in.o file
  113. will tell where the mismatch happens much closer to the
  114. source. The drawback is that we will report the same
  115. mismatch at least twice.
  116. - Enable verbose reporting from modpost to help solving
  117. the section mismatches reported.
  118. config DEBUG_KERNEL
  119. bool "Kernel debugging"
  120. help
  121. Say Y here if you are developing drivers or trying to debug and
  122. identify kernel problems.
  123. config DEBUG_SHIRQ
  124. bool "Debug shared IRQ handlers"
  125. depends on DEBUG_KERNEL && GENERIC_HARDIRQS
  126. help
  127. Enable this to generate a spurious interrupt as soon as a shared
  128. interrupt handler is registered, and just before one is deregistered.
  129. Drivers ought to be able to handle interrupts coming in at those
  130. points; some don't and need to be caught.
  131. config DETECT_SOFTLOCKUP
  132. bool "Detect Soft Lockups"
  133. depends on DEBUG_KERNEL && !S390
  134. default y
  135. help
  136. Say Y here to enable the kernel to detect "soft lockups",
  137. which are bugs that cause the kernel to loop in kernel
  138. mode for more than 60 seconds, without giving other tasks a
  139. chance to run.
  140. When a soft-lockup is detected, the kernel will print the
  141. current stack trace (which you should report), but the
  142. system will stay locked up. This feature has negligible
  143. overhead.
  144. (Note that "hard lockups" are separate type of bugs that
  145. can be detected via the NMI-watchdog, on platforms that
  146. support it.)
  147. config BOOTPARAM_SOFTLOCKUP_PANIC
  148. bool "Panic (Reboot) On Soft Lockups"
  149. depends on DETECT_SOFTLOCKUP
  150. help
  151. Say Y here to enable the kernel to panic on "soft lockups",
  152. which are bugs that cause the kernel to loop in kernel
  153. mode for more than 60 seconds, without giving other tasks a
  154. chance to run.
  155. The panic can be used in combination with panic_timeout,
  156. to cause the system to reboot automatically after a
  157. lockup has been detected. This feature is useful for
  158. high-availability systems that have uptime guarantees and
  159. where a lockup must be resolved ASAP.
  160. Say N if unsure.
  161. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  162. int
  163. depends on DETECT_SOFTLOCKUP
  164. range 0 1
  165. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  166. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  167. config SCHED_DEBUG
  168. bool "Collect scheduler debugging info"
  169. depends on DEBUG_KERNEL && PROC_FS
  170. default y
  171. help
  172. If you say Y here, the /proc/sched_debug file will be provided
  173. that can help debug the scheduler. The runtime overhead of this
  174. option is minimal.
  175. config SCHEDSTATS
  176. bool "Collect scheduler statistics"
  177. depends on DEBUG_KERNEL && PROC_FS
  178. help
  179. If you say Y here, additional code will be inserted into the
  180. scheduler and related routines to collect statistics about
  181. scheduler behavior and provide them in /proc/schedstat. These
  182. stats may be useful for both tuning and debugging the scheduler
  183. If you aren't debugging the scheduler or trying to tune a specific
  184. application, you can say N to avoid the very slight overhead
  185. this adds.
  186. config TIMER_STATS
  187. bool "Collect kernel timers statistics"
  188. depends on DEBUG_KERNEL && PROC_FS
  189. help
  190. If you say Y here, additional code will be inserted into the
  191. timer routines to collect statistics about kernel timers being
  192. reprogrammed. The statistics can be read from /proc/timer_stats.
  193. The statistics collection is started by writing 1 to /proc/timer_stats,
  194. writing 0 stops it. This feature is useful to collect information
  195. about timer usage patterns in kernel and userspace. This feature
  196. is lightweight if enabled in the kernel config but not activated
  197. (it defaults to deactivated on bootup and will only be activated
  198. if some application like powertop activates it explicitly).
  199. config DEBUG_OBJECTS
  200. bool "Debug object operations"
  201. depends on DEBUG_KERNEL
  202. help
  203. If you say Y here, additional code will be inserted into the
  204. kernel to track the life time of various objects and validate
  205. the operations on those objects.
  206. config DEBUG_OBJECTS_SELFTEST
  207. bool "Debug objects selftest"
  208. depends on DEBUG_OBJECTS
  209. help
  210. This enables the selftest of the object debug code.
  211. config DEBUG_OBJECTS_FREE
  212. bool "Debug objects in freed memory"
  213. depends on DEBUG_OBJECTS
  214. help
  215. This enables checks whether a k/v free operation frees an area
  216. which contains an object which has not been deactivated
  217. properly. This can make kmalloc/kfree-intensive workloads
  218. much slower.
  219. config DEBUG_OBJECTS_TIMERS
  220. bool "Debug timer objects"
  221. depends on DEBUG_OBJECTS
  222. help
  223. If you say Y here, additional code will be inserted into the
  224. timer routines to track the life time of timer objects and
  225. validate the timer operations.
  226. config DEBUG_SLAB
  227. bool "Debug slab memory allocations"
  228. depends on DEBUG_KERNEL && SLAB
  229. help
  230. Say Y here to have the kernel do limited verification on memory
  231. allocation as well as poisoning memory on free to catch use of freed
  232. memory. This can make kmalloc/kfree-intensive workloads much slower.
  233. config DEBUG_SLAB_LEAK
  234. bool "Memory leak debugging"
  235. depends on DEBUG_SLAB
  236. config SLUB_DEBUG_ON
  237. bool "SLUB debugging on by default"
  238. depends on SLUB && SLUB_DEBUG
  239. default n
  240. help
  241. Boot with debugging on by default. SLUB boots by default with
  242. the runtime debug capabilities switched off. Enabling this is
  243. equivalent to specifying the "slub_debug" parameter on boot.
  244. There is no support for more fine grained debug control like
  245. possible with slub_debug=xxx. SLUB debugging may be switched
  246. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  247. "slub_debug=-".
  248. config SLUB_STATS
  249. default n
  250. bool "Enable SLUB performance statistics"
  251. depends on SLUB && SLUB_DEBUG && SYSFS
  252. help
  253. SLUB statistics are useful to debug SLUBs allocation behavior in
  254. order find ways to optimize the allocator. This should never be
  255. enabled for production use since keeping statistics slows down
  256. the allocator by a few percentage points. The slabinfo command
  257. supports the determination of the most active slabs to figure
  258. out which slabs are relevant to a particular load.
  259. Try running: slabinfo -DA
  260. config DEBUG_PREEMPT
  261. bool "Debug preemptible kernel"
  262. depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
  263. default y
  264. help
  265. If you say Y here then the kernel will use a debug variant of the
  266. commonly used smp_processor_id() function and will print warnings
  267. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  268. will detect preemption count underflows.
  269. config DEBUG_RT_MUTEXES
  270. bool "RT Mutex debugging, deadlock detection"
  271. depends on DEBUG_KERNEL && RT_MUTEXES
  272. help
  273. This allows rt mutex semantics violations and rt mutex related
  274. deadlocks (lockups) to be detected and reported automatically.
  275. config DEBUG_PI_LIST
  276. bool
  277. default y
  278. depends on DEBUG_RT_MUTEXES
  279. config RT_MUTEX_TESTER
  280. bool "Built-in scriptable tester for rt-mutexes"
  281. depends on DEBUG_KERNEL && RT_MUTEXES
  282. help
  283. This option enables a rt-mutex tester.
  284. config DEBUG_SPINLOCK
  285. bool "Spinlock and rw-lock debugging: basic checks"
  286. depends on DEBUG_KERNEL
  287. help
  288. Say Y here and build SMP to catch missing spinlock initialization
  289. and certain other kinds of spinlock errors commonly made. This is
  290. best used in conjunction with the NMI watchdog so that spinlock
  291. deadlocks are also debuggable.
  292. config DEBUG_MUTEXES
  293. bool "Mutex debugging: basic checks"
  294. depends on DEBUG_KERNEL
  295. help
  296. This feature allows mutex semantics violations to be detected and
  297. reported.
  298. config DEBUG_LOCK_ALLOC
  299. bool "Lock debugging: detect incorrect freeing of live locks"
  300. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  301. select DEBUG_SPINLOCK
  302. select DEBUG_MUTEXES
  303. select LOCKDEP
  304. help
  305. This feature will check whether any held lock (spinlock, rwlock,
  306. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  307. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  308. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  309. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  310. held during task exit.
  311. config PROVE_LOCKING
  312. bool "Lock debugging: prove locking correctness"
  313. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  314. select LOCKDEP
  315. select DEBUG_SPINLOCK
  316. select DEBUG_MUTEXES
  317. select DEBUG_LOCK_ALLOC
  318. default n
  319. help
  320. This feature enables the kernel to prove that all locking
  321. that occurs in the kernel runtime is mathematically
  322. correct: that under no circumstance could an arbitrary (and
  323. not yet triggered) combination of observed locking
  324. sequences (on an arbitrary number of CPUs, running an
  325. arbitrary number of tasks and interrupt contexts) cause a
  326. deadlock.
  327. In short, this feature enables the kernel to report locking
  328. related deadlocks before they actually occur.
  329. The proof does not depend on how hard and complex a
  330. deadlock scenario would be to trigger: how many
  331. participant CPUs, tasks and irq-contexts would be needed
  332. for it to trigger. The proof also does not depend on
  333. timing: if a race and a resulting deadlock is possible
  334. theoretically (no matter how unlikely the race scenario
  335. is), it will be proven so and will immediately be
  336. reported by the kernel (once the event is observed that
  337. makes the deadlock theoretically possible).
  338. If a deadlock is impossible (i.e. the locking rules, as
  339. observed by the kernel, are mathematically correct), the
  340. kernel reports nothing.
  341. NOTE: this feature can also be enabled for rwlocks, mutexes
  342. and rwsems - in which case all dependencies between these
  343. different locking variants are observed and mapped too, and
  344. the proof of observed correctness is also maintained for an
  345. arbitrary combination of these separate locking variants.
  346. For more details, see Documentation/lockdep-design.txt.
  347. config LOCKDEP
  348. bool
  349. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  350. select STACKTRACE
  351. select FRAME_POINTER if !X86 && !MIPS && !PPC
  352. select KALLSYMS
  353. select KALLSYMS_ALL
  354. config LOCK_STAT
  355. bool "Lock usage statistics"
  356. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  357. select LOCKDEP
  358. select DEBUG_SPINLOCK
  359. select DEBUG_MUTEXES
  360. select DEBUG_LOCK_ALLOC
  361. default n
  362. help
  363. This feature enables tracking lock contention points
  364. For more details, see Documentation/lockstat.txt
  365. config DEBUG_LOCKDEP
  366. bool "Lock dependency engine debugging"
  367. depends on DEBUG_KERNEL && LOCKDEP
  368. help
  369. If you say Y here, the lock dependency engine will do
  370. additional runtime checks to debug itself, at the price
  371. of more runtime overhead.
  372. config TRACE_IRQFLAGS
  373. depends on DEBUG_KERNEL
  374. bool
  375. default y
  376. depends on TRACE_IRQFLAGS_SUPPORT
  377. depends on PROVE_LOCKING
  378. config DEBUG_SPINLOCK_SLEEP
  379. bool "Spinlock debugging: sleep-inside-spinlock checking"
  380. depends on DEBUG_KERNEL
  381. help
  382. If you say Y here, various routines which may sleep will become very
  383. noisy if they are called with a spinlock held.
  384. config DEBUG_LOCKING_API_SELFTESTS
  385. bool "Locking API boot-time self-tests"
  386. depends on DEBUG_KERNEL
  387. help
  388. Say Y here if you want the kernel to run a short self-test during
  389. bootup. The self-test checks whether common types of locking bugs
  390. are detected by debugging mechanisms or not. (if you disable
  391. lock debugging then those bugs wont be detected of course.)
  392. The following locking APIs are covered: spinlocks, rwlocks,
  393. mutexes and rwsems.
  394. config STACKTRACE
  395. bool
  396. depends on STACKTRACE_SUPPORT
  397. config DEBUG_KOBJECT
  398. bool "kobject debugging"
  399. depends on DEBUG_KERNEL
  400. help
  401. If you say Y here, some extra kobject debugging messages will be sent
  402. to the syslog.
  403. config DEBUG_HIGHMEM
  404. bool "Highmem debugging"
  405. depends on DEBUG_KERNEL && HIGHMEM
  406. help
  407. This options enables addition error checking for high memory systems.
  408. Disable for production systems.
  409. config DEBUG_BUGVERBOSE
  410. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
  411. depends on BUG
  412. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  413. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
  414. default !EMBEDDED
  415. help
  416. Say Y here to make BUG() panics output the file name and line number
  417. of the BUG call as well as the EIP and oops trace. This aids
  418. debugging but costs about 70-100K of memory.
  419. config DEBUG_INFO
  420. bool "Compile the kernel with debug info"
  421. depends on DEBUG_KERNEL
  422. help
  423. If you say Y here the resulting kernel image will include
  424. debugging info resulting in a larger kernel image.
  425. This adds debug symbols to the kernel and modules (gcc -g), and
  426. is needed if you intend to use kernel crashdump or binary object
  427. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  428. Say Y here only if you plan to debug the kernel.
  429. If unsure, say N.
  430. config DEBUG_VM
  431. bool "Debug VM"
  432. depends on DEBUG_KERNEL
  433. help
  434. Enable this to turn on extended checks in the virtual-memory system
  435. that may impact performance.
  436. If unsure, say N.
  437. config DEBUG_VIRTUAL
  438. bool "Debug VM translations"
  439. depends on DEBUG_KERNEL && X86
  440. help
  441. Enable some costly sanity checks in virtual to page code. This can
  442. catch mistakes with virt_to_page() and friends.
  443. If unsure, say N.
  444. config DEBUG_WRITECOUNT
  445. bool "Debug filesystem writers count"
  446. depends on DEBUG_KERNEL
  447. help
  448. Enable this to catch wrong use of the writers count in struct
  449. vfsmount. This will increase the size of each file struct by
  450. 32 bits.
  451. If unsure, say N.
  452. config DEBUG_MEMORY_INIT
  453. bool "Debug memory initialisation" if EMBEDDED
  454. default !EMBEDDED
  455. help
  456. Enable this for additional checks during memory initialisation.
  457. The sanity checks verify aspects of the VM such as the memory model
  458. and other information provided by the architecture. Verbose
  459. information will be printed at KERN_DEBUG loglevel depending
  460. on the mminit_loglevel= command-line option.
  461. If unsure, say Y
  462. config DEBUG_LIST
  463. bool "Debug linked list manipulation"
  464. depends on DEBUG_KERNEL
  465. help
  466. Enable this to turn on extended checks in the linked-list
  467. walking routines.
  468. If unsure, say N.
  469. config DEBUG_SG
  470. bool "Debug SG table operations"
  471. depends on DEBUG_KERNEL
  472. help
  473. Enable this to turn on checks on scatter-gather tables. This can
  474. help find problems with drivers that do not properly initialize
  475. their sg tables.
  476. If unsure, say N.
  477. config FRAME_POINTER
  478. bool "Compile the kernel with frame pointers"
  479. depends on DEBUG_KERNEL && \
  480. (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
  481. AVR32 || SUPERH || BLACKFIN || MN10300)
  482. default y if DEBUG_INFO && UML
  483. help
  484. If you say Y here the resulting kernel image will be slightly larger
  485. and slower, but it might give very useful debugging information on
  486. some architectures or if you use external debuggers.
  487. If you don't debug the kernel, you can say N.
  488. config BOOT_PRINTK_DELAY
  489. bool "Delay each boot printk message by N milliseconds"
  490. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  491. help
  492. This build option allows you to read kernel boot messages
  493. by inserting a short delay after each one. The delay is
  494. specified in milliseconds on the kernel command line,
  495. using "boot_delay=N".
  496. It is likely that you would also need to use "lpj=M" to preset
  497. the "loops per jiffie" value.
  498. See a previous boot log for the "lpj" value to use for your
  499. system, and then set "lpj=M" before setting "boot_delay=N".
  500. NOTE: Using this option may adversely affect SMP systems.
  501. I.e., processors other than the first one may not boot up.
  502. BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
  503. what it believes to be lockup conditions.
  504. config RCU_TORTURE_TEST
  505. tristate "torture tests for RCU"
  506. depends on DEBUG_KERNEL
  507. default n
  508. help
  509. This option provides a kernel module that runs torture tests
  510. on the RCU infrastructure. The kernel module may be built
  511. after the fact on the running kernel to be tested, if desired.
  512. Say Y here if you want RCU torture tests to be built into
  513. the kernel.
  514. Say M if you want the RCU torture tests to build as a module.
  515. Say N if you are unsure.
  516. config RCU_TORTURE_TEST_RUNNABLE
  517. bool "torture tests for RCU runnable by default"
  518. depends on RCU_TORTURE_TEST = y
  519. default n
  520. help
  521. This option provides a way to build the RCU torture tests
  522. directly into the kernel without them starting up at boot
  523. time. You can use /proc/sys/kernel/rcutorture_runnable
  524. to manually override this setting. This /proc file is
  525. available only when the RCU torture tests have been built
  526. into the kernel.
  527. Say Y here if you want the RCU torture tests to start during
  528. boot (you probably don't).
  529. Say N here if you want the RCU torture tests to start only
  530. after being manually enabled via /proc.
  531. config RCU_CPU_STALL_DETECTOR
  532. bool "Check for stalled CPUs delaying RCU grace periods"
  533. depends on CLASSIC_RCU
  534. default n
  535. help
  536. This option causes RCU to printk information on which
  537. CPUs are delaying the current grace period, but only when
  538. the grace period extends for excessive time periods.
  539. Say Y if you want RCU to perform such checks.
  540. Say N if you are unsure.
  541. config RCU_CPU_STALL_DETECTOR
  542. bool "Check for stalled CPUs delaying RCU grace periods"
  543. depends on CLASSIC_RCU || TREE_RCU
  544. default n
  545. help
  546. This option causes RCU to printk information on which
  547. CPUs are delaying the current grace period, but only when
  548. the grace period extends for excessive time periods.
  549. Say Y if you want RCU to perform such checks.
  550. Say N if you are unsure.
  551. config KPROBES_SANITY_TEST
  552. bool "Kprobes sanity tests"
  553. depends on DEBUG_KERNEL
  554. depends on KPROBES
  555. default n
  556. help
  557. This option provides for testing basic kprobes functionality on
  558. boot. A sample kprobe, jprobe and kretprobe are inserted and
  559. verified for functionality.
  560. Say N if you are unsure.
  561. config BACKTRACE_SELF_TEST
  562. tristate "Self test for the backtrace code"
  563. depends on DEBUG_KERNEL
  564. default n
  565. help
  566. This option provides a kernel module that can be used to test
  567. the kernel stack backtrace code. This option is not useful
  568. for distributions or general kernels, but only for kernel
  569. developers working on architecture code.
  570. Note that if you want to also test saved backtraces, you will
  571. have to enable STACKTRACE as well.
  572. Say N if you are unsure.
  573. config DEBUG_BLOCK_EXT_DEVT
  574. bool "Force extended block device numbers and spread them"
  575. depends on DEBUG_KERNEL
  576. depends on BLOCK
  577. default n
  578. help
  579. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  580. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  581. YOU ARE DOING. Distros, please enable this and fix whatever
  582. is broken.
  583. Conventionally, block device numbers are allocated from
  584. predetermined contiguous area. However, extended block area
  585. may introduce non-contiguous block device numbers. This
  586. option forces most block device numbers to be allocated from
  587. the extended space and spreads them to discover kernel or
  588. userland code paths which assume predetermined contiguous
  589. device number allocation.
  590. Note that turning on this debug option shuffles all the
  591. device numbers for all IDE and SCSI devices including libata
  592. ones, so root partition specified using device number
  593. directly (via rdev or root=MAJ:MIN) won't work anymore.
  594. Textual device names (root=/dev/sdXn) will continue to work.
  595. Say N if you are unsure.
  596. config LKDTM
  597. tristate "Linux Kernel Dump Test Tool Module"
  598. depends on DEBUG_KERNEL
  599. depends on KPROBES
  600. depends on BLOCK
  601. default n
  602. help
  603. This module enables testing of the different dumping mechanisms by
  604. inducing system failures at predefined crash points.
  605. If you don't need it: say N
  606. Choose M here to compile this code as a module. The module will be
  607. called lkdtm.
  608. Documentation on how to use the module can be found in
  609. drivers/misc/lkdtm.c
  610. config FAULT_INJECTION
  611. bool "Fault-injection framework"
  612. depends on DEBUG_KERNEL
  613. help
  614. Provide fault-injection framework.
  615. For more details, see Documentation/fault-injection/.
  616. config FAILSLAB
  617. bool "Fault-injection capability for kmalloc"
  618. depends on FAULT_INJECTION
  619. help
  620. Provide fault-injection capability for kmalloc.
  621. config FAIL_PAGE_ALLOC
  622. bool "Fault-injection capabilitiy for alloc_pages()"
  623. depends on FAULT_INJECTION
  624. help
  625. Provide fault-injection capability for alloc_pages().
  626. config FAIL_MAKE_REQUEST
  627. bool "Fault-injection capability for disk IO"
  628. depends on FAULT_INJECTION && BLOCK
  629. help
  630. Provide fault-injection capability for disk IO.
  631. config FAIL_IO_TIMEOUT
  632. bool "Faul-injection capability for faking disk interrupts"
  633. depends on FAULT_INJECTION && BLOCK
  634. help
  635. Provide fault-injection capability on end IO handling. This
  636. will make the block layer "forget" an interrupt as configured,
  637. thus exercising the error handling.
  638. Only works with drivers that use the generic timeout handling,
  639. for others it wont do anything.
  640. config FAULT_INJECTION_DEBUG_FS
  641. bool "Debugfs entries for fault-injection capabilities"
  642. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  643. help
  644. Enable configuration of fault-injection capabilities via debugfs.
  645. config FAULT_INJECTION_STACKTRACE_FILTER
  646. bool "stacktrace filter for fault-injection capabilities"
  647. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  648. depends on !X86_64
  649. select STACKTRACE
  650. select FRAME_POINTER if !PPC
  651. help
  652. Provide stacktrace filter for fault-injection capabilities
  653. config LATENCYTOP
  654. bool "Latency measuring infrastructure"
  655. select FRAME_POINTER if !MIPS && !PPC
  656. select KALLSYMS
  657. select KALLSYMS_ALL
  658. select STACKTRACE
  659. select SCHEDSTATS
  660. select SCHED_DEBUG
  661. depends on HAVE_LATENCYTOP_SUPPORT
  662. help
  663. Enable this option if you want to use the LatencyTOP tool
  664. to find out which userspace is blocking on what kernel operations.
  665. config SYSCTL_SYSCALL_CHECK
  666. bool "Sysctl checks"
  667. depends on SYSCTL_SYSCALL
  668. ---help---
  669. sys_sysctl uses binary paths that have been found challenging
  670. to properly maintain and use. This enables checks that help
  671. you to keep things correct.
  672. source kernel/trace/Kconfig
  673. config PROVIDE_OHCI1394_DMA_INIT
  674. bool "Remote debugging over FireWire early on boot"
  675. depends on PCI && X86
  676. help
  677. If you want to debug problems which hang or crash the kernel early
  678. on boot and the crashing machine has a FireWire port, you can use
  679. this feature to remotely access the memory of the crashed machine
  680. over FireWire. This employs remote DMA as part of the OHCI1394
  681. specification which is now the standard for FireWire controllers.
  682. With remote DMA, you can monitor the printk buffer remotely using
  683. firescope and access all memory below 4GB using fireproxy from gdb.
  684. Even controlling a kernel debugger is possible using remote DMA.
  685. Usage:
  686. If ohci1394_dma=early is used as boot parameter, it will initialize
  687. all OHCI1394 controllers which are found in the PCI config space.
  688. As all changes to the FireWire bus such as enabling and disabling
  689. devices cause a bus reset and thereby disable remote DMA for all
  690. devices, be sure to have the cable plugged and FireWire enabled on
  691. the debugging host before booting the debug target for debugging.
  692. This code (~1k) is freed after boot. By then, the firewire stack
  693. in charge of the OHCI-1394 controllers should be used instead.
  694. See Documentation/debugging-via-ohci1394.txt for more information.
  695. config FIREWIRE_OHCI_REMOTE_DMA
  696. bool "Remote debugging over FireWire with firewire-ohci"
  697. depends on FIREWIRE_OHCI
  698. help
  699. This option lets you use the FireWire bus for remote debugging
  700. with help of the firewire-ohci driver. It enables unfiltered
  701. remote DMA in firewire-ohci.
  702. See Documentation/debugging-via-ohci1394.txt for more information.
  703. If unsure, say N.
  704. menuconfig BUILD_DOCSRC
  705. bool "Build targets in Documentation/ tree"
  706. depends on HEADERS_CHECK
  707. help
  708. This option attempts to build objects from the source files in the
  709. kernel Documentation/ tree.
  710. Say N if you are unsure.
  711. config DYNAMIC_PRINTK_DEBUG
  712. bool "Enable dynamic printk() call support"
  713. default n
  714. depends on PRINTK
  715. select PRINTK_DEBUG
  716. help
  717. Compiles debug level messages into the kernel, which would not
  718. otherwise be available at runtime. These messages can then be
  719. enabled/disabled on a per module basis. This mechanism implicitly
  720. enables all pr_debug() and dev_dbg() calls. The impact of this
  721. compile option is a larger kernel text size of about 2%.
  722. Usage:
  723. Dynamic debugging is controlled by the debugfs file,
  724. dynamic_printk/modules. This file contains a list of the modules that
  725. can be enabled. The format of the file is the module name, followed
  726. by a set of flags that can be enabled. The first flag is always the
  727. 'enabled' flag. For example:
  728. <module_name> <enabled=0/1>
  729. .
  730. .
  731. .
  732. <module_name> : Name of the module in which the debug call resides
  733. <enabled=0/1> : whether the messages are enabled or not
  734. From a live system:
  735. snd_hda_intel enabled=0
  736. fixup enabled=0
  737. driver enabled=0
  738. Enable a module:
  739. $echo "set enabled=1 <module_name>" > dynamic_printk/modules
  740. Disable a module:
  741. $echo "set enabled=0 <module_name>" > dynamic_printk/modules
  742. Enable all modules:
  743. $echo "set enabled=1 all" > dynamic_printk/modules
  744. Disable all modules:
  745. $echo "set enabled=0 all" > dynamic_printk/modules
  746. Finally, passing "dynamic_printk" at the command line enables
  747. debugging for all modules. This mode can be turned off via the above
  748. disable command.
  749. source "samples/Kconfig"
  750. source "lib/Kconfig.kgdb"