Kconfig.debug 36 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052
  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 STRIP_ASM_SYMS
  48. bool "Strip assembler-generated symbols during link"
  49. default n
  50. help
  51. Strip internal assembler-generated symbols during a link (symbols
  52. that look like '.Lxxx') so they don't pollute the output of
  53. get_wchan() and suchlike.
  54. config UNUSED_SYMBOLS
  55. bool "Enable unused/obsolete exported symbols"
  56. default y if X86
  57. help
  58. Unused but exported symbols make the kernel needlessly bigger. For
  59. that reason most of these unused exports will soon be removed. This
  60. option is provided temporarily to provide a transition period in case
  61. some external kernel module needs one of these symbols anyway. If you
  62. encounter such a case in your module, consider if you are actually
  63. using the right API. (rationale: since nobody in the kernel is using
  64. this in a module, there is a pretty good chance it's actually the
  65. wrong interface to use). If you really need the symbol, please send a
  66. mail to the linux kernel mailing list mentioning the symbol and why
  67. you really need it, and what the merge plan to the mainline kernel for
  68. your module is.
  69. config DEBUG_FS
  70. bool "Debug Filesystem"
  71. depends on SYSFS
  72. help
  73. debugfs is a virtual file system that kernel developers use to put
  74. debugging files into. Enable this option to be able to read and
  75. write to these files.
  76. For detailed documentation on the debugfs API, see
  77. Documentation/DocBook/filesystems.
  78. If unsure, say N.
  79. config HEADERS_CHECK
  80. bool "Run 'make headers_check' when building vmlinux"
  81. depends on !UML
  82. help
  83. This option will extract the user-visible kernel headers whenever
  84. building the kernel, and will run basic sanity checks on them to
  85. ensure that exported files do not attempt to include files which
  86. were not exported, etc.
  87. If you're making modifications to header files which are
  88. relevant for userspace, say 'Y', and check the headers
  89. exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
  90. your build tree), to make sure they're suitable.
  91. config DEBUG_SECTION_MISMATCH
  92. bool "Enable full Section mismatch analysis"
  93. depends on UNDEFINED
  94. # This option is on purpose disabled for now.
  95. # It will be enabled when we are down to a resonable number
  96. # of section mismatch warnings (< 10 for an allyesconfig build)
  97. help
  98. The section mismatch analysis checks if there are illegal
  99. references from one section to another section.
  100. Linux will during link or during runtime drop some sections
  101. and any use of code/data previously in these sections will
  102. most likely result in an oops.
  103. In the code functions and variables are annotated with
  104. __init, __devinit etc. (see full list in include/linux/init.h)
  105. which results in the code/data being placed in specific sections.
  106. The section mismatch analysis is always done after a full
  107. kernel build but enabling this option will in addition
  108. do the following:
  109. - Add the option -fno-inline-functions-called-once to gcc
  110. When inlining a function annotated __init in a non-init
  111. function we would lose the section information and thus
  112. the analysis would not catch the illegal reference.
  113. This option tells gcc to inline less but will also
  114. result in a larger kernel.
  115. - Run the section mismatch analysis for each module/built-in.o
  116. When we run the section mismatch analysis on vmlinux.o we
  117. lose valueble information about where the mismatch was
  118. introduced.
  119. Running the analysis for each module/built-in.o file
  120. will tell where the mismatch happens much closer to the
  121. source. The drawback is that we will report the same
  122. mismatch at least twice.
  123. - Enable verbose reporting from modpost to help solving
  124. the section mismatches reported.
  125. config DEBUG_KERNEL
  126. bool "Kernel debugging"
  127. help
  128. Say Y here if you are developing drivers or trying to debug and
  129. identify kernel problems.
  130. config DEBUG_SHIRQ
  131. bool "Debug shared IRQ handlers"
  132. depends on DEBUG_KERNEL && GENERIC_HARDIRQS
  133. help
  134. Enable this to generate a spurious interrupt as soon as a shared
  135. interrupt handler is registered, and just before one is deregistered.
  136. Drivers ought to be able to handle interrupts coming in at those
  137. points; some don't and need to be caught.
  138. config DETECT_SOFTLOCKUP
  139. bool "Detect Soft Lockups"
  140. depends on DEBUG_KERNEL && !S390
  141. default y
  142. help
  143. Say Y here to enable the kernel to detect "soft lockups",
  144. which are bugs that cause the kernel to loop in kernel
  145. mode for more than 60 seconds, without giving other tasks a
  146. chance to run.
  147. When a soft-lockup is detected, the kernel will print the
  148. current stack trace (which you should report), but the
  149. system will stay locked up. This feature has negligible
  150. overhead.
  151. (Note that "hard lockups" are separate type of bugs that
  152. can be detected via the NMI-watchdog, on platforms that
  153. support it.)
  154. config BOOTPARAM_SOFTLOCKUP_PANIC
  155. bool "Panic (Reboot) On Soft Lockups"
  156. depends on DETECT_SOFTLOCKUP
  157. help
  158. Say Y here to enable the kernel to panic on "soft lockups",
  159. which are bugs that cause the kernel to loop in kernel
  160. mode for more than 60 seconds, without giving other tasks a
  161. chance to run.
  162. The panic can be used in combination with panic_timeout,
  163. to cause the system to reboot automatically after a
  164. lockup has been detected. This feature is useful for
  165. high-availability systems that have uptime guarantees and
  166. where a lockup must be resolved ASAP.
  167. Say N if unsure.
  168. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  169. int
  170. depends on DETECT_SOFTLOCKUP
  171. range 0 1
  172. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  173. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  174. config DETECT_HUNG_TASK
  175. bool "Detect Hung Tasks"
  176. depends on DEBUG_KERNEL
  177. default DETECT_SOFTLOCKUP
  178. help
  179. Say Y here to enable the kernel to detect "hung tasks",
  180. which are bugs that cause the task to be stuck in
  181. uninterruptible "D" state indefinitiley.
  182. When a hung task is detected, the kernel will print the
  183. current stack trace (which you should report), but the
  184. task will stay in uninterruptible state. If lockdep is
  185. enabled then all held locks will also be reported. This
  186. feature has negligible overhead.
  187. config BOOTPARAM_HUNG_TASK_PANIC
  188. bool "Panic (Reboot) On Hung Tasks"
  189. depends on DETECT_HUNG_TASK
  190. help
  191. Say Y here to enable the kernel to panic on "hung tasks",
  192. which are bugs that cause the kernel to leave a task stuck
  193. in uninterruptible "D" state.
  194. The panic can be used in combination with panic_timeout,
  195. to cause the system to reboot automatically after a
  196. hung task has been detected. This feature is useful for
  197. high-availability systems that have uptime guarantees and
  198. where a hung tasks must be resolved ASAP.
  199. Say N if unsure.
  200. config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  201. int
  202. depends on DETECT_HUNG_TASK
  203. range 0 1
  204. default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  205. default 1 if BOOTPARAM_HUNG_TASK_PANIC
  206. config SCHED_DEBUG
  207. bool "Collect scheduler debugging info"
  208. depends on DEBUG_KERNEL && PROC_FS
  209. default y
  210. help
  211. If you say Y here, the /proc/sched_debug file will be provided
  212. that can help debug the scheduler. The runtime overhead of this
  213. option is minimal.
  214. config SCHEDSTATS
  215. bool "Collect scheduler statistics"
  216. depends on DEBUG_KERNEL && PROC_FS
  217. help
  218. If you say Y here, additional code will be inserted into the
  219. scheduler and related routines to collect statistics about
  220. scheduler behavior and provide them in /proc/schedstat. These
  221. stats may be useful for both tuning and debugging the scheduler
  222. If you aren't debugging the scheduler or trying to tune a specific
  223. application, you can say N to avoid the very slight overhead
  224. this adds.
  225. config TIMER_STATS
  226. bool "Collect kernel timers statistics"
  227. depends on DEBUG_KERNEL && PROC_FS
  228. help
  229. If you say Y here, additional code will be inserted into the
  230. timer routines to collect statistics about kernel timers being
  231. reprogrammed. The statistics can be read from /proc/timer_stats.
  232. The statistics collection is started by writing 1 to /proc/timer_stats,
  233. writing 0 stops it. This feature is useful to collect information
  234. about timer usage patterns in kernel and userspace. This feature
  235. is lightweight if enabled in the kernel config but not activated
  236. (it defaults to deactivated on bootup and will only be activated
  237. if some application like powertop activates it explicitly).
  238. config DEBUG_OBJECTS
  239. bool "Debug object operations"
  240. depends on DEBUG_KERNEL
  241. help
  242. If you say Y here, additional code will be inserted into the
  243. kernel to track the life time of various objects and validate
  244. the operations on those objects.
  245. config DEBUG_OBJECTS_SELFTEST
  246. bool "Debug objects selftest"
  247. depends on DEBUG_OBJECTS
  248. help
  249. This enables the selftest of the object debug code.
  250. config DEBUG_OBJECTS_FREE
  251. bool "Debug objects in freed memory"
  252. depends on DEBUG_OBJECTS
  253. help
  254. This enables checks whether a k/v free operation frees an area
  255. which contains an object which has not been deactivated
  256. properly. This can make kmalloc/kfree-intensive workloads
  257. much slower.
  258. config DEBUG_OBJECTS_TIMERS
  259. bool "Debug timer objects"
  260. depends on DEBUG_OBJECTS
  261. help
  262. If you say Y here, additional code will be inserted into the
  263. timer routines to track the life time of timer objects and
  264. validate the timer operations.
  265. config DEBUG_OBJECTS_ENABLE_DEFAULT
  266. int "debug_objects bootup default value (0-1)"
  267. range 0 1
  268. default "1"
  269. depends on DEBUG_OBJECTS
  270. help
  271. Debug objects boot parameter default value
  272. config DEBUG_SLAB
  273. bool "Debug slab memory allocations"
  274. depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
  275. help
  276. Say Y here to have the kernel do limited verification on memory
  277. allocation as well as poisoning memory on free to catch use of freed
  278. memory. This can make kmalloc/kfree-intensive workloads much slower.
  279. config DEBUG_SLAB_LEAK
  280. bool "Memory leak debugging"
  281. depends on DEBUG_SLAB
  282. config SLUB_DEBUG_ON
  283. bool "SLUB debugging on by default"
  284. depends on SLUB && SLUB_DEBUG && !KMEMCHECK
  285. default n
  286. help
  287. Boot with debugging on by default. SLUB boots by default with
  288. the runtime debug capabilities switched off. Enabling this is
  289. equivalent to specifying the "slub_debug" parameter on boot.
  290. There is no support for more fine grained debug control like
  291. possible with slub_debug=xxx. SLUB debugging may be switched
  292. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  293. "slub_debug=-".
  294. config SLUB_STATS
  295. default n
  296. bool "Enable SLUB performance statistics"
  297. depends on SLUB && SLUB_DEBUG && SYSFS
  298. help
  299. SLUB statistics are useful to debug SLUBs allocation behavior in
  300. order find ways to optimize the allocator. This should never be
  301. enabled for production use since keeping statistics slows down
  302. the allocator by a few percentage points. The slabinfo command
  303. supports the determination of the most active slabs to figure
  304. out which slabs are relevant to a particular load.
  305. Try running: slabinfo -DA
  306. config DEBUG_KMEMLEAK
  307. bool "Kernel memory leak detector"
  308. depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
  309. (X86 || ARM || PPC || S390)
  310. select DEBUG_FS if SYSFS
  311. select STACKTRACE if STACKTRACE_SUPPORT
  312. select KALLSYMS
  313. help
  314. Say Y here if you want to enable the memory leak
  315. detector. The memory allocation/freeing is traced in a way
  316. similar to the Boehm's conservative garbage collector, the
  317. difference being that the orphan objects are not freed but
  318. only shown in /sys/kernel/debug/kmemleak. Enabling this
  319. feature will introduce an overhead to memory
  320. allocations. See Documentation/kmemleak.txt for more
  321. details.
  322. Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  323. of finding leaks due to the slab objects poisoning.
  324. In order to access the kmemleak file, debugfs needs to be
  325. mounted (usually at /sys/kernel/debug).
  326. config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
  327. int "Maximum kmemleak early log entries"
  328. depends on DEBUG_KMEMLEAK
  329. range 200 40000
  330. default 400
  331. help
  332. Kmemleak must track all the memory allocations to avoid
  333. reporting false positives. Since memory may be allocated or
  334. freed before kmemleak is initialised, an early log buffer is
  335. used to store these actions. If kmemleak reports "early log
  336. buffer exceeded", please increase this value.
  337. config DEBUG_KMEMLEAK_TEST
  338. tristate "Simple test for the kernel memory leak detector"
  339. depends on DEBUG_KMEMLEAK
  340. help
  341. Say Y or M here to build a test for the kernel memory leak
  342. detector. This option enables a module that explicitly leaks
  343. memory.
  344. If unsure, say N.
  345. config DEBUG_PREEMPT
  346. bool "Debug preemptible kernel"
  347. depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
  348. default y
  349. help
  350. If you say Y here then the kernel will use a debug variant of the
  351. commonly used smp_processor_id() function and will print warnings
  352. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  353. will detect preemption count underflows.
  354. config DEBUG_RT_MUTEXES
  355. bool "RT Mutex debugging, deadlock detection"
  356. depends on DEBUG_KERNEL && RT_MUTEXES
  357. help
  358. This allows rt mutex semantics violations and rt mutex related
  359. deadlocks (lockups) to be detected and reported automatically.
  360. config DEBUG_PI_LIST
  361. bool
  362. default y
  363. depends on DEBUG_RT_MUTEXES
  364. config RT_MUTEX_TESTER
  365. bool "Built-in scriptable tester for rt-mutexes"
  366. depends on DEBUG_KERNEL && RT_MUTEXES
  367. help
  368. This option enables a rt-mutex tester.
  369. config DEBUG_SPINLOCK
  370. bool "Spinlock and rw-lock debugging: basic checks"
  371. depends on DEBUG_KERNEL
  372. help
  373. Say Y here and build SMP to catch missing spinlock initialization
  374. and certain other kinds of spinlock errors commonly made. This is
  375. best used in conjunction with the NMI watchdog so that spinlock
  376. deadlocks are also debuggable.
  377. config DEBUG_MUTEXES
  378. bool "Mutex debugging: basic checks"
  379. depends on DEBUG_KERNEL
  380. help
  381. This feature allows mutex semantics violations to be detected and
  382. reported.
  383. config DEBUG_LOCK_ALLOC
  384. bool "Lock debugging: detect incorrect freeing of live locks"
  385. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  386. select DEBUG_SPINLOCK
  387. select DEBUG_MUTEXES
  388. select LOCKDEP
  389. help
  390. This feature will check whether any held lock (spinlock, rwlock,
  391. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  392. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  393. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  394. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  395. held during task exit.
  396. config PROVE_LOCKING
  397. bool "Lock debugging: prove locking correctness"
  398. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  399. select LOCKDEP
  400. select DEBUG_SPINLOCK
  401. select DEBUG_MUTEXES
  402. select DEBUG_LOCK_ALLOC
  403. default n
  404. help
  405. This feature enables the kernel to prove that all locking
  406. that occurs in the kernel runtime is mathematically
  407. correct: that under no circumstance could an arbitrary (and
  408. not yet triggered) combination of observed locking
  409. sequences (on an arbitrary number of CPUs, running an
  410. arbitrary number of tasks and interrupt contexts) cause a
  411. deadlock.
  412. In short, this feature enables the kernel to report locking
  413. related deadlocks before they actually occur.
  414. The proof does not depend on how hard and complex a
  415. deadlock scenario would be to trigger: how many
  416. participant CPUs, tasks and irq-contexts would be needed
  417. for it to trigger. The proof also does not depend on
  418. timing: if a race and a resulting deadlock is possible
  419. theoretically (no matter how unlikely the race scenario
  420. is), it will be proven so and will immediately be
  421. reported by the kernel (once the event is observed that
  422. makes the deadlock theoretically possible).
  423. If a deadlock is impossible (i.e. the locking rules, as
  424. observed by the kernel, are mathematically correct), the
  425. kernel reports nothing.
  426. NOTE: this feature can also be enabled for rwlocks, mutexes
  427. and rwsems - in which case all dependencies between these
  428. different locking variants are observed and mapped too, and
  429. the proof of observed correctness is also maintained for an
  430. arbitrary combination of these separate locking variants.
  431. For more details, see Documentation/lockdep-design.txt.
  432. config LOCKDEP
  433. bool
  434. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  435. select STACKTRACE
  436. select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
  437. select KALLSYMS
  438. select KALLSYMS_ALL
  439. config LOCK_STAT
  440. bool "Lock usage statistics"
  441. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  442. select LOCKDEP
  443. select DEBUG_SPINLOCK
  444. select DEBUG_MUTEXES
  445. select DEBUG_LOCK_ALLOC
  446. default n
  447. help
  448. This feature enables tracking lock contention points
  449. For more details, see Documentation/lockstat.txt
  450. config DEBUG_LOCKDEP
  451. bool "Lock dependency engine debugging"
  452. depends on DEBUG_KERNEL && LOCKDEP
  453. help
  454. If you say Y here, the lock dependency engine will do
  455. additional runtime checks to debug itself, at the price
  456. of more runtime overhead.
  457. config TRACE_IRQFLAGS
  458. depends on DEBUG_KERNEL
  459. bool
  460. default y
  461. depends on TRACE_IRQFLAGS_SUPPORT
  462. depends on PROVE_LOCKING
  463. config DEBUG_SPINLOCK_SLEEP
  464. bool "Spinlock debugging: sleep-inside-spinlock checking"
  465. depends on DEBUG_KERNEL
  466. help
  467. If you say Y here, various routines which may sleep will become very
  468. noisy if they are called with a spinlock held.
  469. config DEBUG_LOCKING_API_SELFTESTS
  470. bool "Locking API boot-time self-tests"
  471. depends on DEBUG_KERNEL
  472. help
  473. Say Y here if you want the kernel to run a short self-test during
  474. bootup. The self-test checks whether common types of locking bugs
  475. are detected by debugging mechanisms or not. (if you disable
  476. lock debugging then those bugs wont be detected of course.)
  477. The following locking APIs are covered: spinlocks, rwlocks,
  478. mutexes and rwsems.
  479. config STACKTRACE
  480. bool
  481. depends on STACKTRACE_SUPPORT
  482. config DEBUG_KOBJECT
  483. bool "kobject debugging"
  484. depends on DEBUG_KERNEL
  485. help
  486. If you say Y here, some extra kobject debugging messages will be sent
  487. to the syslog.
  488. config DEBUG_HIGHMEM
  489. bool "Highmem debugging"
  490. depends on DEBUG_KERNEL && HIGHMEM
  491. help
  492. This options enables addition error checking for high memory systems.
  493. Disable for production systems.
  494. config DEBUG_BUGVERBOSE
  495. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
  496. depends on BUG
  497. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  498. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
  499. default !EMBEDDED
  500. help
  501. Say Y here to make BUG() panics output the file name and line number
  502. of the BUG call as well as the EIP and oops trace. This aids
  503. debugging but costs about 70-100K of memory.
  504. config DEBUG_INFO
  505. bool "Compile the kernel with debug info"
  506. depends on DEBUG_KERNEL
  507. help
  508. If you say Y here the resulting kernel image will include
  509. debugging info resulting in a larger kernel image.
  510. This adds debug symbols to the kernel and modules (gcc -g), and
  511. is needed if you intend to use kernel crashdump or binary object
  512. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  513. Say Y here only if you plan to debug the kernel.
  514. If unsure, say N.
  515. config DEBUG_VM
  516. bool "Debug VM"
  517. depends on DEBUG_KERNEL
  518. help
  519. Enable this to turn on extended checks in the virtual-memory system
  520. that may impact performance.
  521. If unsure, say N.
  522. config DEBUG_VIRTUAL
  523. bool "Debug VM translations"
  524. depends on DEBUG_KERNEL && X86
  525. help
  526. Enable some costly sanity checks in virtual to page code. This can
  527. catch mistakes with virt_to_page() and friends.
  528. If unsure, say N.
  529. config DEBUG_NOMMU_REGIONS
  530. bool "Debug the global anon/private NOMMU mapping region tree"
  531. depends on DEBUG_KERNEL && !MMU
  532. help
  533. This option causes the global tree of anonymous and private mapping
  534. regions to be regularly checked for invalid topology.
  535. config DEBUG_WRITECOUNT
  536. bool "Debug filesystem writers count"
  537. depends on DEBUG_KERNEL
  538. help
  539. Enable this to catch wrong use of the writers count in struct
  540. vfsmount. This will increase the size of each file struct by
  541. 32 bits.
  542. If unsure, say N.
  543. config DEBUG_MEMORY_INIT
  544. bool "Debug memory initialisation" if EMBEDDED
  545. default !EMBEDDED
  546. help
  547. Enable this for additional checks during memory initialisation.
  548. The sanity checks verify aspects of the VM such as the memory model
  549. and other information provided by the architecture. Verbose
  550. information will be printed at KERN_DEBUG loglevel depending
  551. on the mminit_loglevel= command-line option.
  552. If unsure, say Y
  553. config DEBUG_LIST
  554. bool "Debug linked list manipulation"
  555. depends on DEBUG_KERNEL
  556. help
  557. Enable this to turn on extended checks in the linked-list
  558. walking routines.
  559. If unsure, say N.
  560. config DEBUG_SG
  561. bool "Debug SG table operations"
  562. depends on DEBUG_KERNEL
  563. help
  564. Enable this to turn on checks on scatter-gather tables. This can
  565. help find problems with drivers that do not properly initialize
  566. their sg tables.
  567. If unsure, say N.
  568. config DEBUG_NOTIFIERS
  569. bool "Debug notifier call chains"
  570. depends on DEBUG_KERNEL
  571. help
  572. Enable this to turn on sanity checking for notifier call chains.
  573. This is most useful for kernel developers to make sure that
  574. modules properly unregister themselves from notifier chains.
  575. This is a relatively cheap check but if you care about maximum
  576. performance, say N.
  577. config DEBUG_CREDENTIALS
  578. bool "Debug credential management"
  579. depends on DEBUG_KERNEL
  580. help
  581. Enable this to turn on some debug checking for credential
  582. management. The additional code keeps track of the number of
  583. pointers from task_structs to any given cred struct, and checks to
  584. see that this number never exceeds the usage count of the cred
  585. struct.
  586. Furthermore, if SELinux is enabled, this also checks that the
  587. security pointer in the cred struct is never seen to be invalid.
  588. If unsure, say N.
  589. #
  590. # Select this config option from the architecture Kconfig, if it
  591. # it is preferred to always offer frame pointers as a config
  592. # option on the architecture (regardless of KERNEL_DEBUG):
  593. #
  594. config ARCH_WANT_FRAME_POINTERS
  595. bool
  596. help
  597. config FRAME_POINTER
  598. bool "Compile the kernel with frame pointers"
  599. depends on DEBUG_KERNEL && \
  600. (CRIS || M68K || M68KNOMMU || FRV || UML || \
  601. AVR32 || SUPERH || BLACKFIN || MN10300) || \
  602. ARCH_WANT_FRAME_POINTERS
  603. default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
  604. help
  605. If you say Y here the resulting kernel image will be slightly
  606. larger and slower, but it gives very useful debugging information
  607. in case of kernel bugs. (precise oopses/stacktraces/warnings)
  608. config BOOT_PRINTK_DELAY
  609. bool "Delay each boot printk message by N milliseconds"
  610. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  611. help
  612. This build option allows you to read kernel boot messages
  613. by inserting a short delay after each one. The delay is
  614. specified in milliseconds on the kernel command line,
  615. using "boot_delay=N".
  616. It is likely that you would also need to use "lpj=M" to preset
  617. the "loops per jiffie" value.
  618. See a previous boot log for the "lpj" value to use for your
  619. system, and then set "lpj=M" before setting "boot_delay=N".
  620. NOTE: Using this option may adversely affect SMP systems.
  621. I.e., processors other than the first one may not boot up.
  622. BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
  623. what it believes to be lockup conditions.
  624. config RCU_TORTURE_TEST
  625. tristate "torture tests for RCU"
  626. depends on DEBUG_KERNEL
  627. default n
  628. help
  629. This option provides a kernel module that runs torture tests
  630. on the RCU infrastructure. The kernel module may be built
  631. after the fact on the running kernel to be tested, if desired.
  632. Say Y here if you want RCU torture tests to be built into
  633. the kernel.
  634. Say M if you want the RCU torture tests to build as a module.
  635. Say N if you are unsure.
  636. config RCU_TORTURE_TEST_RUNNABLE
  637. bool "torture tests for RCU runnable by default"
  638. depends on RCU_TORTURE_TEST = y
  639. default n
  640. help
  641. This option provides a way to build the RCU torture tests
  642. directly into the kernel without them starting up at boot
  643. time. You can use /proc/sys/kernel/rcutorture_runnable
  644. to manually override this setting. This /proc file is
  645. available only when the RCU torture tests have been built
  646. into the kernel.
  647. Say Y here if you want the RCU torture tests to start during
  648. boot (you probably don't).
  649. Say N here if you want the RCU torture tests to start only
  650. after being manually enabled via /proc.
  651. config RCU_CPU_STALL_DETECTOR
  652. bool "Check for stalled CPUs delaying RCU grace periods"
  653. depends on TREE_RCU || TREE_PREEMPT_RCU
  654. default n
  655. help
  656. This option causes RCU to printk information on which
  657. CPUs are delaying the current grace period, but only when
  658. the grace period extends for excessive time periods.
  659. Say Y if you want RCU to perform such checks.
  660. Say N if you are unsure.
  661. config KPROBES_SANITY_TEST
  662. bool "Kprobes sanity tests"
  663. depends on DEBUG_KERNEL
  664. depends on KPROBES
  665. default n
  666. help
  667. This option provides for testing basic kprobes functionality on
  668. boot. A sample kprobe, jprobe and kretprobe are inserted and
  669. verified for functionality.
  670. Say N if you are unsure.
  671. config BACKTRACE_SELF_TEST
  672. tristate "Self test for the backtrace code"
  673. depends on DEBUG_KERNEL
  674. default n
  675. help
  676. This option provides a kernel module that can be used to test
  677. the kernel stack backtrace code. This option is not useful
  678. for distributions or general kernels, but only for kernel
  679. developers working on architecture code.
  680. Note that if you want to also test saved backtraces, you will
  681. have to enable STACKTRACE as well.
  682. Say N if you are unsure.
  683. config DEBUG_BLOCK_EXT_DEVT
  684. bool "Force extended block device numbers and spread them"
  685. depends on DEBUG_KERNEL
  686. depends on BLOCK
  687. default n
  688. help
  689. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  690. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  691. YOU ARE DOING. Distros, please enable this and fix whatever
  692. is broken.
  693. Conventionally, block device numbers are allocated from
  694. predetermined contiguous area. However, extended block area
  695. may introduce non-contiguous block device numbers. This
  696. option forces most block device numbers to be allocated from
  697. the extended space and spreads them to discover kernel or
  698. userland code paths which assume predetermined contiguous
  699. device number allocation.
  700. Note that turning on this debug option shuffles all the
  701. device numbers for all IDE and SCSI devices including libata
  702. ones, so root partition specified using device number
  703. directly (via rdev or root=MAJ:MIN) won't work anymore.
  704. Textual device names (root=/dev/sdXn) will continue to work.
  705. Say N if you are unsure.
  706. config DEBUG_FORCE_WEAK_PER_CPU
  707. bool "Force weak per-cpu definitions"
  708. depends on DEBUG_KERNEL
  709. help
  710. s390 and alpha require percpu variables in modules to be
  711. defined weak to work around addressing range issue which
  712. puts the following two restrictions on percpu variable
  713. definitions.
  714. 1. percpu symbols must be unique whether static or not
  715. 2. percpu variables can't be defined inside a function
  716. To ensure that generic code follows the above rules, this
  717. option forces all percpu variables to be defined as weak.
  718. config LKDTM
  719. tristate "Linux Kernel Dump Test Tool Module"
  720. depends on DEBUG_KERNEL
  721. depends on KPROBES
  722. depends on BLOCK
  723. default n
  724. help
  725. This module enables testing of the different dumping mechanisms by
  726. inducing system failures at predefined crash points.
  727. If you don't need it: say N
  728. Choose M here to compile this code as a module. The module will be
  729. called lkdtm.
  730. Documentation on how to use the module can be found in
  731. drivers/misc/lkdtm.c
  732. config FAULT_INJECTION
  733. bool "Fault-injection framework"
  734. depends on DEBUG_KERNEL
  735. help
  736. Provide fault-injection framework.
  737. For more details, see Documentation/fault-injection/.
  738. config FAILSLAB
  739. bool "Fault-injection capability for kmalloc"
  740. depends on FAULT_INJECTION
  741. depends on SLAB || SLUB
  742. help
  743. Provide fault-injection capability for kmalloc.
  744. config FAIL_PAGE_ALLOC
  745. bool "Fault-injection capabilitiy for alloc_pages()"
  746. depends on FAULT_INJECTION
  747. help
  748. Provide fault-injection capability for alloc_pages().
  749. config FAIL_MAKE_REQUEST
  750. bool "Fault-injection capability for disk IO"
  751. depends on FAULT_INJECTION && BLOCK
  752. help
  753. Provide fault-injection capability for disk IO.
  754. config FAIL_IO_TIMEOUT
  755. bool "Faul-injection capability for faking disk interrupts"
  756. depends on FAULT_INJECTION && BLOCK
  757. help
  758. Provide fault-injection capability on end IO handling. This
  759. will make the block layer "forget" an interrupt as configured,
  760. thus exercising the error handling.
  761. Only works with drivers that use the generic timeout handling,
  762. for others it wont do anything.
  763. config FAULT_INJECTION_DEBUG_FS
  764. bool "Debugfs entries for fault-injection capabilities"
  765. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  766. help
  767. Enable configuration of fault-injection capabilities via debugfs.
  768. config FAULT_INJECTION_STACKTRACE_FILTER
  769. bool "stacktrace filter for fault-injection capabilities"
  770. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  771. depends on !X86_64
  772. select STACKTRACE
  773. select FRAME_POINTER if !PPC && !S390
  774. help
  775. Provide stacktrace filter for fault-injection capabilities
  776. config LATENCYTOP
  777. bool "Latency measuring infrastructure"
  778. select FRAME_POINTER if !MIPS && !PPC && !S390
  779. select KALLSYMS
  780. select KALLSYMS_ALL
  781. select STACKTRACE
  782. select SCHEDSTATS
  783. select SCHED_DEBUG
  784. depends on HAVE_LATENCYTOP_SUPPORT
  785. help
  786. Enable this option if you want to use the LatencyTOP tool
  787. to find out which userspace is blocking on what kernel operations.
  788. config SYSCTL_SYSCALL_CHECK
  789. bool "Sysctl checks"
  790. depends on SYSCTL_SYSCALL
  791. ---help---
  792. sys_sysctl uses binary paths that have been found challenging
  793. to properly maintain and use. This enables checks that help
  794. you to keep things correct.
  795. source mm/Kconfig.debug
  796. source kernel/trace/Kconfig
  797. config PROVIDE_OHCI1394_DMA_INIT
  798. bool "Remote debugging over FireWire early on boot"
  799. depends on PCI && X86
  800. help
  801. If you want to debug problems which hang or crash the kernel early
  802. on boot and the crashing machine has a FireWire port, you can use
  803. this feature to remotely access the memory of the crashed machine
  804. over FireWire. This employs remote DMA as part of the OHCI1394
  805. specification which is now the standard for FireWire controllers.
  806. With remote DMA, you can monitor the printk buffer remotely using
  807. firescope and access all memory below 4GB using fireproxy from gdb.
  808. Even controlling a kernel debugger is possible using remote DMA.
  809. Usage:
  810. If ohci1394_dma=early is used as boot parameter, it will initialize
  811. all OHCI1394 controllers which are found in the PCI config space.
  812. As all changes to the FireWire bus such as enabling and disabling
  813. devices cause a bus reset and thereby disable remote DMA for all
  814. devices, be sure to have the cable plugged and FireWire enabled on
  815. the debugging host before booting the debug target for debugging.
  816. This code (~1k) is freed after boot. By then, the firewire stack
  817. in charge of the OHCI-1394 controllers should be used instead.
  818. See Documentation/debugging-via-ohci1394.txt for more information.
  819. config FIREWIRE_OHCI_REMOTE_DMA
  820. bool "Remote debugging over FireWire with firewire-ohci"
  821. depends on FIREWIRE_OHCI
  822. help
  823. This option lets you use the FireWire bus for remote debugging
  824. with help of the firewire-ohci driver. It enables unfiltered
  825. remote DMA in firewire-ohci.
  826. See Documentation/debugging-via-ohci1394.txt for more information.
  827. If unsure, say N.
  828. config BUILD_DOCSRC
  829. bool "Build targets in Documentation/ tree"
  830. depends on HEADERS_CHECK
  831. help
  832. This option attempts to build objects from the source files in the
  833. kernel Documentation/ tree.
  834. Say N if you are unsure.
  835. config DYNAMIC_DEBUG
  836. bool "Enable dynamic printk() support"
  837. default n
  838. depends on PRINTK
  839. depends on DEBUG_FS
  840. help
  841. Compiles debug level messages into the kernel, which would not
  842. otherwise be available at runtime. These messages can then be
  843. enabled/disabled based on various levels of scope - per source file,
  844. function, module, format string, and line number. This mechanism
  845. implicitly enables all pr_debug() and dev_dbg() calls. The impact of
  846. this compile option is a larger kernel text size of about 2%.
  847. Usage:
  848. Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
  849. which is contained in the 'debugfs' filesystem. Thus, the debugfs
  850. filesystem must first be mounted before making use of this feature.
  851. We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
  852. file contains a list of the debug statements that can be enabled. The
  853. format for each line of the file is:
  854. filename:lineno [module]function flags format
  855. filename : source file of the debug statement
  856. lineno : line number of the debug statement
  857. module : module that contains the debug statement
  858. function : function that contains the debug statement
  859. flags : 'p' means the line is turned 'on' for printing
  860. format : the format used for the debug statement
  861. From a live system:
  862. nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
  863. # filename:lineno [module]function flags format
  864. fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
  865. fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
  866. fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
  867. Example usage:
  868. // enable the message at line 1603 of file svcsock.c
  869. nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
  870. <debugfs>/dynamic_debug/ddebug
  871. // enable all the messages in file svcsock.c
  872. nullarbor:~ # echo -n 'file svcsock.c +p' >
  873. <debugfs>/dynamic_debug/ddebug
  874. // enable all the messages in the NFS server module
  875. nullarbor:~ # echo -n 'module nfsd +p' >
  876. <debugfs>/dynamic_debug/ddebug
  877. // enable all 12 messages in the function svc_process()
  878. nullarbor:~ # echo -n 'func svc_process +p' >
  879. <debugfs>/dynamic_debug/ddebug
  880. // disable all 12 messages in the function svc_process()
  881. nullarbor:~ # echo -n 'func svc_process -p' >
  882. <debugfs>/dynamic_debug/ddebug
  883. See Documentation/dynamic-debug-howto.txt for additional information.
  884. config DMA_API_DEBUG
  885. bool "Enable debugging of DMA-API usage"
  886. depends on HAVE_DMA_API_DEBUG
  887. help
  888. Enable this option to debug the use of the DMA API by device drivers.
  889. With this option you will be able to detect common bugs in device
  890. drivers like double-freeing of DMA mappings or freeing mappings that
  891. were never allocated.
  892. This option causes a performance degredation. Use only if you want
  893. to debug device drivers. If unsure, say N.
  894. source "samples/Kconfig"
  895. source "lib/Kconfig.kgdb"
  896. source "lib/Kconfig.kmemcheck"