Kconfig.debug 39 KB

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  1. config PRINTK_TIME
  2. bool "Show timing information on printks"
  3. depends on PRINTK
  4. help
  5. Selecting this option causes timing information to be
  6. included in printk output. This allows you to measure
  7. the interval between kernel operations, including bootup
  8. operations. This is useful for identifying long delays
  9. in kernel startup.
  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 || (BLACKFIN)
  94. default y
  95. # This option is on purpose disabled for now.
  96. # It will be enabled when we are down to a reasonable number
  97. # of section mismatch warnings (< 10 for an allyesconfig build)
  98. help
  99. The section mismatch analysis checks if there are illegal
  100. references from one section to another section.
  101. Linux will during link or during runtime drop some sections
  102. and any use of code/data previously in these sections will
  103. most likely result in an oops.
  104. In the code functions and variables are annotated with
  105. __init, __devinit etc. (see full list in include/linux/init.h)
  106. which results in the code/data being placed in specific sections.
  107. The section mismatch analysis is always done after a full
  108. kernel build but enabling this option will in addition
  109. do the following:
  110. - Add the option -fno-inline-functions-called-once to gcc
  111. When inlining a function annotated __init in a non-init
  112. function we would lose the section information and thus
  113. the analysis would not catch the illegal reference.
  114. This option tells gcc to inline less but will also
  115. result in a larger kernel.
  116. - Run the section mismatch analysis for each module/built-in.o
  117. When we run the section mismatch analysis on vmlinux.o we
  118. lose valueble information about where the mismatch was
  119. introduced.
  120. Running the analysis for each module/built-in.o file
  121. will tell where the mismatch happens much closer to the
  122. source. The drawback is that we will report the same
  123. mismatch at least twice.
  124. - Enable verbose reporting from modpost to help solving
  125. the section mismatches reported.
  126. config DEBUG_KERNEL
  127. bool "Kernel debugging"
  128. help
  129. Say Y here if you are developing drivers or trying to debug and
  130. identify kernel problems.
  131. config DEBUG_SHIRQ
  132. bool "Debug shared IRQ handlers"
  133. depends on DEBUG_KERNEL && GENERIC_HARDIRQS
  134. help
  135. Enable this to generate a spurious interrupt as soon as a shared
  136. interrupt handler is registered, and just before one is deregistered.
  137. Drivers ought to be able to handle interrupts coming in at those
  138. points; some don't and need to be caught.
  139. config LOCKUP_DETECTOR
  140. bool "Detect Hard and Soft Lockups"
  141. depends on DEBUG_KERNEL && !S390
  142. help
  143. Say Y here to enable the kernel to act as a watchdog to detect
  144. hard and soft lockups.
  145. Softlockups are bugs that cause the kernel to loop in kernel
  146. mode for more than 60 seconds, without giving other tasks a
  147. chance to run. The current stack trace is displayed upon
  148. detection and the system will stay locked up.
  149. Hardlockups are bugs that cause the CPU to loop in kernel mode
  150. for more than 60 seconds, without letting other interrupts have a
  151. chance to run. The current stack trace is displayed upon detection
  152. and the system will stay locked up.
  153. The overhead should be minimal. A periodic hrtimer runs to
  154. generate interrupts and kick the watchdog task every 10-12 seconds.
  155. An NMI is generated every 60 seconds or so to check for hardlockups.
  156. config HARDLOCKUP_DETECTOR
  157. def_bool LOCKUP_DETECTOR && PERF_EVENTS && HAVE_PERF_EVENTS_NMI
  158. config BOOTPARAM_SOFTLOCKUP_PANIC
  159. bool "Panic (Reboot) On Soft Lockups"
  160. depends on LOCKUP_DETECTOR
  161. help
  162. Say Y here to enable the kernel to panic on "soft lockups",
  163. which are bugs that cause the kernel to loop in kernel
  164. mode for more than 60 seconds, without giving other tasks a
  165. chance to run.
  166. The panic can be used in combination with panic_timeout,
  167. to cause the system to reboot automatically after a
  168. lockup has been detected. This feature is useful for
  169. high-availability systems that have uptime guarantees and
  170. where a lockup must be resolved ASAP.
  171. Say N if unsure.
  172. config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
  173. int
  174. depends on LOCKUP_DETECTOR
  175. range 0 1
  176. default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
  177. default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
  178. config DETECT_HUNG_TASK
  179. bool "Detect Hung Tasks"
  180. depends on DEBUG_KERNEL
  181. default DETECT_SOFTLOCKUP
  182. help
  183. Say Y here to enable the kernel to detect "hung tasks",
  184. which are bugs that cause the task to be stuck in
  185. uninterruptible "D" state indefinitiley.
  186. When a hung task is detected, the kernel will print the
  187. current stack trace (which you should report), but the
  188. task will stay in uninterruptible state. If lockdep is
  189. enabled then all held locks will also be reported. This
  190. feature has negligible overhead.
  191. config BOOTPARAM_HUNG_TASK_PANIC
  192. bool "Panic (Reboot) On Hung Tasks"
  193. depends on DETECT_HUNG_TASK
  194. help
  195. Say Y here to enable the kernel to panic on "hung tasks",
  196. which are bugs that cause the kernel to leave a task stuck
  197. in uninterruptible "D" state.
  198. The panic can be used in combination with panic_timeout,
  199. to cause the system to reboot automatically after a
  200. hung task has been detected. This feature is useful for
  201. high-availability systems that have uptime guarantees and
  202. where a hung tasks must be resolved ASAP.
  203. Say N if unsure.
  204. config BOOTPARAM_HUNG_TASK_PANIC_VALUE
  205. int
  206. depends on DETECT_HUNG_TASK
  207. range 0 1
  208. default 0 if !BOOTPARAM_HUNG_TASK_PANIC
  209. default 1 if BOOTPARAM_HUNG_TASK_PANIC
  210. config SCHED_DEBUG
  211. bool "Collect scheduler debugging info"
  212. depends on DEBUG_KERNEL && PROC_FS
  213. default y
  214. help
  215. If you say Y here, the /proc/sched_debug file will be provided
  216. that can help debug the scheduler. The runtime overhead of this
  217. option is minimal.
  218. config SCHEDSTATS
  219. bool "Collect scheduler statistics"
  220. depends on DEBUG_KERNEL && PROC_FS
  221. help
  222. If you say Y here, additional code will be inserted into the
  223. scheduler and related routines to collect statistics about
  224. scheduler behavior and provide them in /proc/schedstat. These
  225. stats may be useful for both tuning and debugging the scheduler
  226. If you aren't debugging the scheduler or trying to tune a specific
  227. application, you can say N to avoid the very slight overhead
  228. this adds.
  229. config TIMER_STATS
  230. bool "Collect kernel timers statistics"
  231. depends on DEBUG_KERNEL && PROC_FS
  232. help
  233. If you say Y here, additional code will be inserted into the
  234. timer routines to collect statistics about kernel timers being
  235. reprogrammed. The statistics can be read from /proc/timer_stats.
  236. The statistics collection is started by writing 1 to /proc/timer_stats,
  237. writing 0 stops it. This feature is useful to collect information
  238. about timer usage patterns in kernel and userspace. This feature
  239. is lightweight if enabled in the kernel config but not activated
  240. (it defaults to deactivated on bootup and will only be activated
  241. if some application like powertop activates it explicitly).
  242. config DEBUG_OBJECTS
  243. bool "Debug object operations"
  244. depends on DEBUG_KERNEL
  245. help
  246. If you say Y here, additional code will be inserted into the
  247. kernel to track the life time of various objects and validate
  248. the operations on those objects.
  249. config DEBUG_OBJECTS_SELFTEST
  250. bool "Debug objects selftest"
  251. depends on DEBUG_OBJECTS
  252. help
  253. This enables the selftest of the object debug code.
  254. config DEBUG_OBJECTS_FREE
  255. bool "Debug objects in freed memory"
  256. depends on DEBUG_OBJECTS
  257. help
  258. This enables checks whether a k/v free operation frees an area
  259. which contains an object which has not been deactivated
  260. properly. This can make kmalloc/kfree-intensive workloads
  261. much slower.
  262. config DEBUG_OBJECTS_TIMERS
  263. bool "Debug timer objects"
  264. depends on DEBUG_OBJECTS
  265. help
  266. If you say Y here, additional code will be inserted into the
  267. timer routines to track the life time of timer objects and
  268. validate the timer operations.
  269. config DEBUG_OBJECTS_WORK
  270. bool "Debug work objects"
  271. depends on DEBUG_OBJECTS
  272. help
  273. If you say Y here, additional code will be inserted into the
  274. work queue routines to track the life time of work objects and
  275. validate the work operations.
  276. config DEBUG_OBJECTS_ENABLE_DEFAULT
  277. int "debug_objects bootup default value (0-1)"
  278. range 0 1
  279. default "1"
  280. depends on DEBUG_OBJECTS
  281. help
  282. Debug objects boot parameter default value
  283. config DEBUG_SLAB
  284. bool "Debug slab memory allocations"
  285. depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
  286. help
  287. Say Y here to have the kernel do limited verification on memory
  288. allocation as well as poisoning memory on free to catch use of freed
  289. memory. This can make kmalloc/kfree-intensive workloads much slower.
  290. config DEBUG_SLAB_LEAK
  291. bool "Memory leak debugging"
  292. depends on DEBUG_SLAB
  293. config SLUB_DEBUG_ON
  294. bool "SLUB debugging on by default"
  295. depends on SLUB && SLUB_DEBUG && !KMEMCHECK
  296. default n
  297. help
  298. Boot with debugging on by default. SLUB boots by default with
  299. the runtime debug capabilities switched off. Enabling this is
  300. equivalent to specifying the "slub_debug" parameter on boot.
  301. There is no support for more fine grained debug control like
  302. possible with slub_debug=xxx. SLUB debugging may be switched
  303. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  304. "slub_debug=-".
  305. config SLUB_STATS
  306. default n
  307. bool "Enable SLUB performance statistics"
  308. depends on SLUB && SLUB_DEBUG && SYSFS
  309. help
  310. SLUB statistics are useful to debug SLUBs allocation behavior in
  311. order find ways to optimize the allocator. This should never be
  312. enabled for production use since keeping statistics slows down
  313. the allocator by a few percentage points. The slabinfo command
  314. supports the determination of the most active slabs to figure
  315. out which slabs are relevant to a particular load.
  316. Try running: slabinfo -DA
  317. config DEBUG_KMEMLEAK
  318. bool "Kernel memory leak detector"
  319. depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
  320. (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE)
  321. select DEBUG_FS if SYSFS
  322. select STACKTRACE if STACKTRACE_SUPPORT
  323. select KALLSYMS
  324. select CRC32
  325. help
  326. Say Y here if you want to enable the memory leak
  327. detector. The memory allocation/freeing is traced in a way
  328. similar to the Boehm's conservative garbage collector, the
  329. difference being that the orphan objects are not freed but
  330. only shown in /sys/kernel/debug/kmemleak. Enabling this
  331. feature will introduce an overhead to memory
  332. allocations. See Documentation/kmemleak.txt for more
  333. details.
  334. Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
  335. of finding leaks due to the slab objects poisoning.
  336. In order to access the kmemleak file, debugfs needs to be
  337. mounted (usually at /sys/kernel/debug).
  338. config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
  339. int "Maximum kmemleak early log entries"
  340. depends on DEBUG_KMEMLEAK
  341. range 200 40000
  342. default 400
  343. help
  344. Kmemleak must track all the memory allocations to avoid
  345. reporting false positives. Since memory may be allocated or
  346. freed before kmemleak is initialised, an early log buffer is
  347. used to store these actions. If kmemleak reports "early log
  348. buffer exceeded", please increase this value.
  349. config DEBUG_KMEMLEAK_TEST
  350. tristate "Simple test for the kernel memory leak detector"
  351. depends on DEBUG_KMEMLEAK
  352. help
  353. Say Y or M here to build a test for the kernel memory leak
  354. detector. This option enables a module that explicitly leaks
  355. memory.
  356. If unsure, say N.
  357. config DEBUG_PREEMPT
  358. bool "Debug preemptible kernel"
  359. depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
  360. default y
  361. help
  362. If you say Y here then the kernel will use a debug variant of the
  363. commonly used smp_processor_id() function and will print warnings
  364. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  365. will detect preemption count underflows.
  366. config DEBUG_RT_MUTEXES
  367. bool "RT Mutex debugging, deadlock detection"
  368. depends on DEBUG_KERNEL && RT_MUTEXES
  369. help
  370. This allows rt mutex semantics violations and rt mutex related
  371. deadlocks (lockups) to be detected and reported automatically.
  372. config DEBUG_PI_LIST
  373. bool
  374. default y
  375. depends on DEBUG_RT_MUTEXES
  376. config RT_MUTEX_TESTER
  377. bool "Built-in scriptable tester for rt-mutexes"
  378. depends on DEBUG_KERNEL && RT_MUTEXES
  379. help
  380. This option enables a rt-mutex tester.
  381. config DEBUG_SPINLOCK
  382. bool "Spinlock and rw-lock debugging: basic checks"
  383. depends on DEBUG_KERNEL
  384. help
  385. Say Y here and build SMP to catch missing spinlock initialization
  386. and certain other kinds of spinlock errors commonly made. This is
  387. best used in conjunction with the NMI watchdog so that spinlock
  388. deadlocks are also debuggable.
  389. config DEBUG_MUTEXES
  390. bool "Mutex debugging: basic checks"
  391. depends on DEBUG_KERNEL
  392. help
  393. This feature allows mutex semantics violations to be detected and
  394. reported.
  395. config DEBUG_LOCK_ALLOC
  396. bool "Lock debugging: detect incorrect freeing of live locks"
  397. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  398. select DEBUG_SPINLOCK
  399. select DEBUG_MUTEXES
  400. select LOCKDEP
  401. help
  402. This feature will check whether any held lock (spinlock, rwlock,
  403. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  404. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  405. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  406. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  407. held during task exit.
  408. config PROVE_LOCKING
  409. bool "Lock debugging: prove locking correctness"
  410. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  411. select LOCKDEP
  412. select DEBUG_SPINLOCK
  413. select DEBUG_MUTEXES
  414. select DEBUG_LOCK_ALLOC
  415. default n
  416. help
  417. This feature enables the kernel to prove that all locking
  418. that occurs in the kernel runtime is mathematically
  419. correct: that under no circumstance could an arbitrary (and
  420. not yet triggered) combination of observed locking
  421. sequences (on an arbitrary number of CPUs, running an
  422. arbitrary number of tasks and interrupt contexts) cause a
  423. deadlock.
  424. In short, this feature enables the kernel to report locking
  425. related deadlocks before they actually occur.
  426. The proof does not depend on how hard and complex a
  427. deadlock scenario would be to trigger: how many
  428. participant CPUs, tasks and irq-contexts would be needed
  429. for it to trigger. The proof also does not depend on
  430. timing: if a race and a resulting deadlock is possible
  431. theoretically (no matter how unlikely the race scenario
  432. is), it will be proven so and will immediately be
  433. reported by the kernel (once the event is observed that
  434. makes the deadlock theoretically possible).
  435. If a deadlock is impossible (i.e. the locking rules, as
  436. observed by the kernel, are mathematically correct), the
  437. kernel reports nothing.
  438. NOTE: this feature can also be enabled for rwlocks, mutexes
  439. and rwsems - in which case all dependencies between these
  440. different locking variants are observed and mapped too, and
  441. the proof of observed correctness is also maintained for an
  442. arbitrary combination of these separate locking variants.
  443. For more details, see Documentation/lockdep-design.txt.
  444. config PROVE_RCU
  445. bool "RCU debugging: prove RCU correctness"
  446. depends on PROVE_LOCKING
  447. default n
  448. help
  449. This feature enables lockdep extensions that check for correct
  450. use of RCU APIs. This is currently under development. Say Y
  451. if you want to debug RCU usage or help work on the PROVE_RCU
  452. feature.
  453. Say N if you are unsure.
  454. config PROVE_RCU_REPEATEDLY
  455. bool "RCU debugging: don't disable PROVE_RCU on first splat"
  456. depends on PROVE_RCU
  457. default n
  458. help
  459. By itself, PROVE_RCU will disable checking upon issuing the
  460. first warning (or "splat"). This feature prevents such
  461. disabling, allowing multiple RCU-lockdep warnings to be printed
  462. on a single reboot.
  463. Say N if you are unsure.
  464. config LOCKDEP
  465. bool
  466. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  467. select STACKTRACE
  468. select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
  469. select KALLSYMS
  470. select KALLSYMS_ALL
  471. config LOCK_STAT
  472. bool "Lock usage statistics"
  473. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  474. select LOCKDEP
  475. select DEBUG_SPINLOCK
  476. select DEBUG_MUTEXES
  477. select DEBUG_LOCK_ALLOC
  478. default n
  479. help
  480. This feature enables tracking lock contention points
  481. For more details, see Documentation/lockstat.txt
  482. This also enables lock events required by "perf lock",
  483. subcommand of perf.
  484. If you want to use "perf lock", you also need to turn on
  485. CONFIG_EVENT_TRACING.
  486. CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
  487. (CONFIG_LOCKDEP defines "acquire" and "release" events.)
  488. config DEBUG_LOCKDEP
  489. bool "Lock dependency engine debugging"
  490. depends on DEBUG_KERNEL && LOCKDEP
  491. help
  492. If you say Y here, the lock dependency engine will do
  493. additional runtime checks to debug itself, at the price
  494. of more runtime overhead.
  495. config TRACE_IRQFLAGS
  496. depends on DEBUG_KERNEL
  497. bool
  498. default y
  499. depends on TRACE_IRQFLAGS_SUPPORT
  500. depends on PROVE_LOCKING
  501. config DEBUG_SPINLOCK_SLEEP
  502. bool "Spinlock debugging: sleep-inside-spinlock checking"
  503. depends on DEBUG_KERNEL
  504. help
  505. If you say Y here, various routines which may sleep will become very
  506. noisy if they are called with a spinlock held.
  507. config DEBUG_LOCKING_API_SELFTESTS
  508. bool "Locking API boot-time self-tests"
  509. depends on DEBUG_KERNEL
  510. help
  511. Say Y here if you want the kernel to run a short self-test during
  512. bootup. The self-test checks whether common types of locking bugs
  513. are detected by debugging mechanisms or not. (if you disable
  514. lock debugging then those bugs wont be detected of course.)
  515. The following locking APIs are covered: spinlocks, rwlocks,
  516. mutexes and rwsems.
  517. config STACKTRACE
  518. bool
  519. depends on STACKTRACE_SUPPORT
  520. config DEBUG_KOBJECT
  521. bool "kobject debugging"
  522. depends on DEBUG_KERNEL
  523. help
  524. If you say Y here, some extra kobject debugging messages will be sent
  525. to the syslog.
  526. config DEBUG_HIGHMEM
  527. bool "Highmem debugging"
  528. depends on DEBUG_KERNEL && HIGHMEM
  529. help
  530. This options enables addition error checking for high memory systems.
  531. Disable for production systems.
  532. config DEBUG_BUGVERBOSE
  533. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
  534. depends on BUG
  535. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  536. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
  537. default y
  538. help
  539. Say Y here to make BUG() panics output the file name and line number
  540. of the BUG call as well as the EIP and oops trace. This aids
  541. debugging but costs about 70-100K of memory.
  542. config DEBUG_INFO
  543. bool "Compile the kernel with debug info"
  544. depends on DEBUG_KERNEL
  545. help
  546. If you say Y here the resulting kernel image will include
  547. debugging info resulting in a larger kernel image.
  548. This adds debug symbols to the kernel and modules (gcc -g), and
  549. is needed if you intend to use kernel crashdump or binary object
  550. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  551. Say Y here only if you plan to debug the kernel.
  552. If unsure, say N.
  553. config DEBUG_VM
  554. bool "Debug VM"
  555. depends on DEBUG_KERNEL
  556. help
  557. Enable this to turn on extended checks in the virtual-memory system
  558. that may impact performance.
  559. If unsure, say N.
  560. config DEBUG_VIRTUAL
  561. bool "Debug VM translations"
  562. depends on DEBUG_KERNEL && X86
  563. help
  564. Enable some costly sanity checks in virtual to page code. This can
  565. catch mistakes with virt_to_page() and friends.
  566. If unsure, say N.
  567. config DEBUG_NOMMU_REGIONS
  568. bool "Debug the global anon/private NOMMU mapping region tree"
  569. depends on DEBUG_KERNEL && !MMU
  570. help
  571. This option causes the global tree of anonymous and private mapping
  572. regions to be regularly checked for invalid topology.
  573. config DEBUG_WRITECOUNT
  574. bool "Debug filesystem writers count"
  575. depends on DEBUG_KERNEL
  576. help
  577. Enable this to catch wrong use of the writers count in struct
  578. vfsmount. This will increase the size of each file struct by
  579. 32 bits.
  580. If unsure, say N.
  581. config DEBUG_MEMORY_INIT
  582. bool "Debug memory initialisation" if EMBEDDED
  583. default !EMBEDDED
  584. help
  585. Enable this for additional checks during memory initialisation.
  586. The sanity checks verify aspects of the VM such as the memory model
  587. and other information provided by the architecture. Verbose
  588. information will be printed at KERN_DEBUG loglevel depending
  589. on the mminit_loglevel= command-line option.
  590. If unsure, say Y
  591. config DEBUG_LIST
  592. bool "Debug linked list manipulation"
  593. depends on DEBUG_KERNEL
  594. help
  595. Enable this to turn on extended checks in the linked-list
  596. walking routines.
  597. If unsure, say N.
  598. config DEBUG_SG
  599. bool "Debug SG table operations"
  600. depends on DEBUG_KERNEL
  601. help
  602. Enable this to turn on checks on scatter-gather tables. This can
  603. help find problems with drivers that do not properly initialize
  604. their sg tables.
  605. If unsure, say N.
  606. config DEBUG_NOTIFIERS
  607. bool "Debug notifier call chains"
  608. depends on DEBUG_KERNEL
  609. help
  610. Enable this to turn on sanity checking for notifier call chains.
  611. This is most useful for kernel developers to make sure that
  612. modules properly unregister themselves from notifier chains.
  613. This is a relatively cheap check but if you care about maximum
  614. performance, say N.
  615. config DEBUG_CREDENTIALS
  616. bool "Debug credential management"
  617. depends on DEBUG_KERNEL
  618. help
  619. Enable this to turn on some debug checking for credential
  620. management. The additional code keeps track of the number of
  621. pointers from task_structs to any given cred struct, and checks to
  622. see that this number never exceeds the usage count of the cred
  623. struct.
  624. Furthermore, if SELinux is enabled, this also checks that the
  625. security pointer in the cred struct is never seen to be invalid.
  626. If unsure, say N.
  627. #
  628. # Select this config option from the architecture Kconfig, if it
  629. # it is preferred to always offer frame pointers as a config
  630. # option on the architecture (regardless of KERNEL_DEBUG):
  631. #
  632. config ARCH_WANT_FRAME_POINTERS
  633. bool
  634. help
  635. config FRAME_POINTER
  636. bool "Compile the kernel with frame pointers"
  637. depends on DEBUG_KERNEL && \
  638. (CRIS || M68K || M68KNOMMU || FRV || UML || \
  639. AVR32 || SUPERH || BLACKFIN || MN10300) || \
  640. ARCH_WANT_FRAME_POINTERS
  641. default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
  642. help
  643. If you say Y here the resulting kernel image will be slightly
  644. larger and slower, but it gives very useful debugging information
  645. in case of kernel bugs. (precise oopses/stacktraces/warnings)
  646. config BOOT_PRINTK_DELAY
  647. bool "Delay each boot printk message by N milliseconds"
  648. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  649. help
  650. This build option allows you to read kernel boot messages
  651. by inserting a short delay after each one. The delay is
  652. specified in milliseconds on the kernel command line,
  653. using "boot_delay=N".
  654. It is likely that you would also need to use "lpj=M" to preset
  655. the "loops per jiffie" value.
  656. See a previous boot log for the "lpj" value to use for your
  657. system, and then set "lpj=M" before setting "boot_delay=N".
  658. NOTE: Using this option may adversely affect SMP systems.
  659. I.e., processors other than the first one may not boot up.
  660. BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
  661. what it believes to be lockup conditions.
  662. config RCU_TORTURE_TEST
  663. tristate "torture tests for RCU"
  664. depends on DEBUG_KERNEL
  665. default n
  666. help
  667. This option provides a kernel module that runs torture tests
  668. on the RCU infrastructure. The kernel module may be built
  669. after the fact on the running kernel to be tested, if desired.
  670. Say Y here if you want RCU torture tests to be built into
  671. the kernel.
  672. Say M if you want the RCU torture tests to build as a module.
  673. Say N if you are unsure.
  674. config RCU_TORTURE_TEST_RUNNABLE
  675. bool "torture tests for RCU runnable by default"
  676. depends on RCU_TORTURE_TEST = y
  677. default n
  678. help
  679. This option provides a way to build the RCU torture tests
  680. directly into the kernel without them starting up at boot
  681. time. You can use /proc/sys/kernel/rcutorture_runnable
  682. to manually override this setting. This /proc file is
  683. available only when the RCU torture tests have been built
  684. into the kernel.
  685. Say Y here if you want the RCU torture tests to start during
  686. boot (you probably don't).
  687. Say N here if you want the RCU torture tests to start only
  688. after being manually enabled via /proc.
  689. config RCU_CPU_STALL_DETECTOR
  690. bool "Check for stalled CPUs delaying RCU grace periods"
  691. depends on TREE_RCU || TREE_PREEMPT_RCU
  692. default y
  693. help
  694. This option causes RCU to printk information on which
  695. CPUs are delaying the current grace period, but only when
  696. the grace period extends for excessive time periods.
  697. Say N if you want to disable such checks.
  698. Say Y if you are unsure.
  699. config RCU_CPU_STALL_VERBOSE
  700. bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
  701. depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
  702. default y
  703. help
  704. This option causes RCU to printk detailed per-task information
  705. for any tasks that are stalling the current RCU grace period.
  706. Say N if you are unsure.
  707. Say Y if you want to enable such checks.
  708. config KPROBES_SANITY_TEST
  709. bool "Kprobes sanity tests"
  710. depends on DEBUG_KERNEL
  711. depends on KPROBES
  712. default n
  713. help
  714. This option provides for testing basic kprobes functionality on
  715. boot. A sample kprobe, jprobe and kretprobe are inserted and
  716. verified for functionality.
  717. Say N if you are unsure.
  718. config BACKTRACE_SELF_TEST
  719. tristate "Self test for the backtrace code"
  720. depends on DEBUG_KERNEL
  721. default n
  722. help
  723. This option provides a kernel module that can be used to test
  724. the kernel stack backtrace code. This option is not useful
  725. for distributions or general kernels, but only for kernel
  726. developers working on architecture code.
  727. Note that if you want to also test saved backtraces, you will
  728. have to enable STACKTRACE as well.
  729. Say N if you are unsure.
  730. config DEBUG_BLOCK_EXT_DEVT
  731. bool "Force extended block device numbers and spread them"
  732. depends on DEBUG_KERNEL
  733. depends on BLOCK
  734. default n
  735. help
  736. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  737. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  738. YOU ARE DOING. Distros, please enable this and fix whatever
  739. is broken.
  740. Conventionally, block device numbers are allocated from
  741. predetermined contiguous area. However, extended block area
  742. may introduce non-contiguous block device numbers. This
  743. option forces most block device numbers to be allocated from
  744. the extended space and spreads them to discover kernel or
  745. userland code paths which assume predetermined contiguous
  746. device number allocation.
  747. Note that turning on this debug option shuffles all the
  748. device numbers for all IDE and SCSI devices including libata
  749. ones, so root partition specified using device number
  750. directly (via rdev or root=MAJ:MIN) won't work anymore.
  751. Textual device names (root=/dev/sdXn) will continue to work.
  752. Say N if you are unsure.
  753. config DEBUG_FORCE_WEAK_PER_CPU
  754. bool "Force weak per-cpu definitions"
  755. depends on DEBUG_KERNEL
  756. help
  757. s390 and alpha require percpu variables in modules to be
  758. defined weak to work around addressing range issue which
  759. puts the following two restrictions on percpu variable
  760. definitions.
  761. 1. percpu symbols must be unique whether static or not
  762. 2. percpu variables can't be defined inside a function
  763. To ensure that generic code follows the above rules, this
  764. option forces all percpu variables to be defined as weak.
  765. config LKDTM
  766. tristate "Linux Kernel Dump Test Tool Module"
  767. depends on DEBUG_FS
  768. depends on BLOCK
  769. default n
  770. help
  771. This module enables testing of the different dumping mechanisms by
  772. inducing system failures at predefined crash points.
  773. If you don't need it: say N
  774. Choose M here to compile this code as a module. The module will be
  775. called lkdtm.
  776. Documentation on how to use the module can be found in
  777. Documentation/fault-injection/provoke-crashes.txt
  778. config CPU_NOTIFIER_ERROR_INJECT
  779. tristate "CPU notifier error injection module"
  780. depends on HOTPLUG_CPU && DEBUG_KERNEL
  781. help
  782. This option provides a kernel module that can be used to test
  783. the error handling of the cpu notifiers
  784. To compile this code as a module, choose M here: the module will
  785. be called cpu-notifier-error-inject.
  786. If unsure, say N.
  787. config FAULT_INJECTION
  788. bool "Fault-injection framework"
  789. depends on DEBUG_KERNEL
  790. help
  791. Provide fault-injection framework.
  792. For more details, see Documentation/fault-injection/.
  793. config FAILSLAB
  794. bool "Fault-injection capability for kmalloc"
  795. depends on FAULT_INJECTION
  796. depends on SLAB || SLUB
  797. help
  798. Provide fault-injection capability for kmalloc.
  799. config FAIL_PAGE_ALLOC
  800. bool "Fault-injection capabilitiy for alloc_pages()"
  801. depends on FAULT_INJECTION
  802. help
  803. Provide fault-injection capability for alloc_pages().
  804. config FAIL_MAKE_REQUEST
  805. bool "Fault-injection capability for disk IO"
  806. depends on FAULT_INJECTION && BLOCK
  807. help
  808. Provide fault-injection capability for disk IO.
  809. config FAIL_IO_TIMEOUT
  810. bool "Faul-injection capability for faking disk interrupts"
  811. depends on FAULT_INJECTION && BLOCK
  812. help
  813. Provide fault-injection capability on end IO handling. This
  814. will make the block layer "forget" an interrupt as configured,
  815. thus exercising the error handling.
  816. Only works with drivers that use the generic timeout handling,
  817. for others it wont do anything.
  818. config FAULT_INJECTION_DEBUG_FS
  819. bool "Debugfs entries for fault-injection capabilities"
  820. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  821. help
  822. Enable configuration of fault-injection capabilities via debugfs.
  823. config FAULT_INJECTION_STACKTRACE_FILTER
  824. bool "stacktrace filter for fault-injection capabilities"
  825. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  826. depends on !X86_64
  827. select STACKTRACE
  828. select FRAME_POINTER if !PPC && !S390
  829. help
  830. Provide stacktrace filter for fault-injection capabilities
  831. config LATENCYTOP
  832. bool "Latency measuring infrastructure"
  833. select FRAME_POINTER if !MIPS && !PPC && !S390
  834. select KALLSYMS
  835. select KALLSYMS_ALL
  836. select STACKTRACE
  837. select SCHEDSTATS
  838. select SCHED_DEBUG
  839. depends on HAVE_LATENCYTOP_SUPPORT
  840. help
  841. Enable this option if you want to use the LatencyTOP tool
  842. to find out which userspace is blocking on what kernel operations.
  843. config SYSCTL_SYSCALL_CHECK
  844. bool "Sysctl checks"
  845. depends on SYSCTL
  846. ---help---
  847. sys_sysctl uses binary paths that have been found challenging
  848. to properly maintain and use. This enables checks that help
  849. you to keep things correct.
  850. source mm/Kconfig.debug
  851. source kernel/trace/Kconfig
  852. config PROVIDE_OHCI1394_DMA_INIT
  853. bool "Remote debugging over FireWire early on boot"
  854. depends on PCI && X86
  855. help
  856. If you want to debug problems which hang or crash the kernel early
  857. on boot and the crashing machine has a FireWire port, you can use
  858. this feature to remotely access the memory of the crashed machine
  859. over FireWire. This employs remote DMA as part of the OHCI1394
  860. specification which is now the standard for FireWire controllers.
  861. With remote DMA, you can monitor the printk buffer remotely using
  862. firescope and access all memory below 4GB using fireproxy from gdb.
  863. Even controlling a kernel debugger is possible using remote DMA.
  864. Usage:
  865. If ohci1394_dma=early is used as boot parameter, it will initialize
  866. all OHCI1394 controllers which are found in the PCI config space.
  867. As all changes to the FireWire bus such as enabling and disabling
  868. devices cause a bus reset and thereby disable remote DMA for all
  869. devices, be sure to have the cable plugged and FireWire enabled on
  870. the debugging host before booting the debug target for debugging.
  871. This code (~1k) is freed after boot. By then, the firewire stack
  872. in charge of the OHCI-1394 controllers should be used instead.
  873. See Documentation/debugging-via-ohci1394.txt for more information.
  874. config FIREWIRE_OHCI_REMOTE_DMA
  875. bool "Remote debugging over FireWire with firewire-ohci"
  876. depends on FIREWIRE_OHCI
  877. help
  878. This option lets you use the FireWire bus for remote debugging
  879. with help of the firewire-ohci driver. It enables unfiltered
  880. remote DMA in firewire-ohci.
  881. See Documentation/debugging-via-ohci1394.txt for more information.
  882. If unsure, say N.
  883. config BUILD_DOCSRC
  884. bool "Build targets in Documentation/ tree"
  885. depends on HEADERS_CHECK
  886. help
  887. This option attempts to build objects from the source files in the
  888. kernel Documentation/ tree.
  889. Say N if you are unsure.
  890. config DYNAMIC_DEBUG
  891. bool "Enable dynamic printk() support"
  892. default n
  893. depends on PRINTK
  894. depends on DEBUG_FS
  895. help
  896. Compiles debug level messages into the kernel, which would not
  897. otherwise be available at runtime. These messages can then be
  898. enabled/disabled based on various levels of scope - per source file,
  899. function, module, format string, and line number. This mechanism
  900. implicitly enables all pr_debug() and dev_dbg() calls. The impact of
  901. this compile option is a larger kernel text size of about 2%.
  902. Usage:
  903. Dynamic debugging is controlled via the 'dynamic_debug/control' file,
  904. which is contained in the 'debugfs' filesystem. Thus, the debugfs
  905. filesystem must first be mounted before making use of this feature.
  906. We refer the control file as: <debugfs>/dynamic_debug/control. This
  907. file contains a list of the debug statements that can be enabled. The
  908. format for each line of the file is:
  909. filename:lineno [module]function flags format
  910. filename : source file of the debug statement
  911. lineno : line number of the debug statement
  912. module : module that contains the debug statement
  913. function : function that contains the debug statement
  914. flags : 'p' means the line is turned 'on' for printing
  915. format : the format used for the debug statement
  916. From a live system:
  917. nullarbor:~ # cat <debugfs>/dynamic_debug/control
  918. # filename:lineno [module]function flags format
  919. fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
  920. fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
  921. fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
  922. Example usage:
  923. // enable the message at line 1603 of file svcsock.c
  924. nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
  925. <debugfs>/dynamic_debug/control
  926. // enable all the messages in file svcsock.c
  927. nullarbor:~ # echo -n 'file svcsock.c +p' >
  928. <debugfs>/dynamic_debug/control
  929. // enable all the messages in the NFS server module
  930. nullarbor:~ # echo -n 'module nfsd +p' >
  931. <debugfs>/dynamic_debug/control
  932. // enable all 12 messages in the function svc_process()
  933. nullarbor:~ # echo -n 'func svc_process +p' >
  934. <debugfs>/dynamic_debug/control
  935. // disable all 12 messages in the function svc_process()
  936. nullarbor:~ # echo -n 'func svc_process -p' >
  937. <debugfs>/dynamic_debug/control
  938. See Documentation/dynamic-debug-howto.txt for additional information.
  939. config DMA_API_DEBUG
  940. bool "Enable debugging of DMA-API usage"
  941. depends on HAVE_DMA_API_DEBUG
  942. help
  943. Enable this option to debug the use of the DMA API by device drivers.
  944. With this option you will be able to detect common bugs in device
  945. drivers like double-freeing of DMA mappings or freeing mappings that
  946. were never allocated.
  947. This option causes a performance degredation. Use only if you want
  948. to debug device drivers. If unsure, say N.
  949. config ATOMIC64_SELFTEST
  950. bool "Perform an atomic64_t self-test at boot"
  951. help
  952. Enable this option to test the atomic64_t functions at boot.
  953. If unsure, say N.
  954. source "samples/Kconfig"
  955. source "lib/Kconfig.kgdb"
  956. source "lib/Kconfig.kmemcheck"