Kconfig.debug 31 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 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_OBJECTS_ENABLE_DEFAULT
  227. int "debug_objects bootup default value (0-1)"
  228. range 0 1
  229. default "1"
  230. depends on DEBUG_OBJECTS
  231. help
  232. Debug objects boot parameter default value
  233. config DEBUG_SLAB
  234. bool "Debug slab memory allocations"
  235. depends on DEBUG_KERNEL && SLAB
  236. help
  237. Say Y here to have the kernel do limited verification on memory
  238. allocation as well as poisoning memory on free to catch use of freed
  239. memory. This can make kmalloc/kfree-intensive workloads much slower.
  240. config DEBUG_SLAB_LEAK
  241. bool "Memory leak debugging"
  242. depends on DEBUG_SLAB
  243. config SLUB_DEBUG_ON
  244. bool "SLUB debugging on by default"
  245. depends on SLUB && SLUB_DEBUG
  246. default n
  247. help
  248. Boot with debugging on by default. SLUB boots by default with
  249. the runtime debug capabilities switched off. Enabling this is
  250. equivalent to specifying the "slub_debug" parameter on boot.
  251. There is no support for more fine grained debug control like
  252. possible with slub_debug=xxx. SLUB debugging may be switched
  253. off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
  254. "slub_debug=-".
  255. config SLUB_STATS
  256. default n
  257. bool "Enable SLUB performance statistics"
  258. depends on SLUB && SLUB_DEBUG && SYSFS
  259. help
  260. SLUB statistics are useful to debug SLUBs allocation behavior in
  261. order find ways to optimize the allocator. This should never be
  262. enabled for production use since keeping statistics slows down
  263. the allocator by a few percentage points. The slabinfo command
  264. supports the determination of the most active slabs to figure
  265. out which slabs are relevant to a particular load.
  266. Try running: slabinfo -DA
  267. config DEBUG_PREEMPT
  268. bool "Debug preemptible kernel"
  269. depends on DEBUG_KERNEL && PREEMPT && (TRACE_IRQFLAGS_SUPPORT || PPC64)
  270. default y
  271. help
  272. If you say Y here then the kernel will use a debug variant of the
  273. commonly used smp_processor_id() function and will print warnings
  274. if kernel code uses it in a preemption-unsafe way. Also, the kernel
  275. will detect preemption count underflows.
  276. config DEBUG_RT_MUTEXES
  277. bool "RT Mutex debugging, deadlock detection"
  278. depends on DEBUG_KERNEL && RT_MUTEXES
  279. help
  280. This allows rt mutex semantics violations and rt mutex related
  281. deadlocks (lockups) to be detected and reported automatically.
  282. config DEBUG_PI_LIST
  283. bool
  284. default y
  285. depends on DEBUG_RT_MUTEXES
  286. config RT_MUTEX_TESTER
  287. bool "Built-in scriptable tester for rt-mutexes"
  288. depends on DEBUG_KERNEL && RT_MUTEXES
  289. help
  290. This option enables a rt-mutex tester.
  291. config DEBUG_SPINLOCK
  292. bool "Spinlock and rw-lock debugging: basic checks"
  293. depends on DEBUG_KERNEL
  294. help
  295. Say Y here and build SMP to catch missing spinlock initialization
  296. and certain other kinds of spinlock errors commonly made. This is
  297. best used in conjunction with the NMI watchdog so that spinlock
  298. deadlocks are also debuggable.
  299. config DEBUG_MUTEXES
  300. bool "Mutex debugging: basic checks"
  301. depends on DEBUG_KERNEL
  302. help
  303. This feature allows mutex semantics violations to be detected and
  304. reported.
  305. config DEBUG_LOCK_ALLOC
  306. bool "Lock debugging: detect incorrect freeing of live locks"
  307. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  308. select DEBUG_SPINLOCK
  309. select DEBUG_MUTEXES
  310. select LOCKDEP
  311. help
  312. This feature will check whether any held lock (spinlock, rwlock,
  313. mutex or rwsem) is incorrectly freed by the kernel, via any of the
  314. memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
  315. vfree(), etc.), whether a live lock is incorrectly reinitialized via
  316. spin_lock_init()/mutex_init()/etc., or whether there is any lock
  317. held during task exit.
  318. config PROVE_LOCKING
  319. bool "Lock debugging: prove locking correctness"
  320. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  321. select LOCKDEP
  322. select DEBUG_SPINLOCK
  323. select DEBUG_MUTEXES
  324. select DEBUG_LOCK_ALLOC
  325. default n
  326. help
  327. This feature enables the kernel to prove that all locking
  328. that occurs in the kernel runtime is mathematically
  329. correct: that under no circumstance could an arbitrary (and
  330. not yet triggered) combination of observed locking
  331. sequences (on an arbitrary number of CPUs, running an
  332. arbitrary number of tasks and interrupt contexts) cause a
  333. deadlock.
  334. In short, this feature enables the kernel to report locking
  335. related deadlocks before they actually occur.
  336. The proof does not depend on how hard and complex a
  337. deadlock scenario would be to trigger: how many
  338. participant CPUs, tasks and irq-contexts would be needed
  339. for it to trigger. The proof also does not depend on
  340. timing: if a race and a resulting deadlock is possible
  341. theoretically (no matter how unlikely the race scenario
  342. is), it will be proven so and will immediately be
  343. reported by the kernel (once the event is observed that
  344. makes the deadlock theoretically possible).
  345. If a deadlock is impossible (i.e. the locking rules, as
  346. observed by the kernel, are mathematically correct), the
  347. kernel reports nothing.
  348. NOTE: this feature can also be enabled for rwlocks, mutexes
  349. and rwsems - in which case all dependencies between these
  350. different locking variants are observed and mapped too, and
  351. the proof of observed correctness is also maintained for an
  352. arbitrary combination of these separate locking variants.
  353. For more details, see Documentation/lockdep-design.txt.
  354. config LOCKDEP
  355. bool
  356. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  357. select STACKTRACE
  358. select FRAME_POINTER if !X86 && !MIPS && !PPC
  359. select KALLSYMS
  360. select KALLSYMS_ALL
  361. config LOCK_STAT
  362. bool "Lock usage statistics"
  363. depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
  364. select LOCKDEP
  365. select DEBUG_SPINLOCK
  366. select DEBUG_MUTEXES
  367. select DEBUG_LOCK_ALLOC
  368. default n
  369. help
  370. This feature enables tracking lock contention points
  371. For more details, see Documentation/lockstat.txt
  372. config DEBUG_LOCKDEP
  373. bool "Lock dependency engine debugging"
  374. depends on DEBUG_KERNEL && LOCKDEP
  375. help
  376. If you say Y here, the lock dependency engine will do
  377. additional runtime checks to debug itself, at the price
  378. of more runtime overhead.
  379. config TRACE_IRQFLAGS
  380. depends on DEBUG_KERNEL
  381. bool
  382. default y
  383. depends on TRACE_IRQFLAGS_SUPPORT
  384. depends on PROVE_LOCKING
  385. config DEBUG_SPINLOCK_SLEEP
  386. bool "Spinlock debugging: sleep-inside-spinlock checking"
  387. depends on DEBUG_KERNEL
  388. help
  389. If you say Y here, various routines which may sleep will become very
  390. noisy if they are called with a spinlock held.
  391. config DEBUG_LOCKING_API_SELFTESTS
  392. bool "Locking API boot-time self-tests"
  393. depends on DEBUG_KERNEL
  394. help
  395. Say Y here if you want the kernel to run a short self-test during
  396. bootup. The self-test checks whether common types of locking bugs
  397. are detected by debugging mechanisms or not. (if you disable
  398. lock debugging then those bugs wont be detected of course.)
  399. The following locking APIs are covered: spinlocks, rwlocks,
  400. mutexes and rwsems.
  401. config STACKTRACE
  402. bool
  403. depends on STACKTRACE_SUPPORT
  404. config DEBUG_KOBJECT
  405. bool "kobject debugging"
  406. depends on DEBUG_KERNEL
  407. help
  408. If you say Y here, some extra kobject debugging messages will be sent
  409. to the syslog.
  410. config DEBUG_HIGHMEM
  411. bool "Highmem debugging"
  412. depends on DEBUG_KERNEL && HIGHMEM
  413. help
  414. This options enables addition error checking for high memory systems.
  415. Disable for production systems.
  416. config DEBUG_BUGVERBOSE
  417. bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
  418. depends on BUG
  419. depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
  420. FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
  421. default !EMBEDDED
  422. help
  423. Say Y here to make BUG() panics output the file name and line number
  424. of the BUG call as well as the EIP and oops trace. This aids
  425. debugging but costs about 70-100K of memory.
  426. config DEBUG_INFO
  427. bool "Compile the kernel with debug info"
  428. depends on DEBUG_KERNEL
  429. help
  430. If you say Y here the resulting kernel image will include
  431. debugging info resulting in a larger kernel image.
  432. This adds debug symbols to the kernel and modules (gcc -g), and
  433. is needed if you intend to use kernel crashdump or binary object
  434. tools like crash, kgdb, LKCD, gdb, etc on the kernel.
  435. Say Y here only if you plan to debug the kernel.
  436. If unsure, say N.
  437. config DEBUG_VM
  438. bool "Debug VM"
  439. depends on DEBUG_KERNEL
  440. help
  441. Enable this to turn on extended checks in the virtual-memory system
  442. that may impact performance.
  443. If unsure, say N.
  444. config DEBUG_VIRTUAL
  445. bool "Debug VM translations"
  446. depends on DEBUG_KERNEL && X86
  447. help
  448. Enable some costly sanity checks in virtual to page code. This can
  449. catch mistakes with virt_to_page() and friends.
  450. If unsure, say N.
  451. config DEBUG_WRITECOUNT
  452. bool "Debug filesystem writers count"
  453. depends on DEBUG_KERNEL
  454. help
  455. Enable this to catch wrong use of the writers count in struct
  456. vfsmount. This will increase the size of each file struct by
  457. 32 bits.
  458. If unsure, say N.
  459. config DEBUG_MEMORY_INIT
  460. bool "Debug memory initialisation" if EMBEDDED
  461. default !EMBEDDED
  462. help
  463. Enable this for additional checks during memory initialisation.
  464. The sanity checks verify aspects of the VM such as the memory model
  465. and other information provided by the architecture. Verbose
  466. information will be printed at KERN_DEBUG loglevel depending
  467. on the mminit_loglevel= command-line option.
  468. If unsure, say Y
  469. config DEBUG_LIST
  470. bool "Debug linked list manipulation"
  471. depends on DEBUG_KERNEL
  472. help
  473. Enable this to turn on extended checks in the linked-list
  474. walking routines.
  475. If unsure, say N.
  476. config DEBUG_SG
  477. bool "Debug SG table operations"
  478. depends on DEBUG_KERNEL
  479. help
  480. Enable this to turn on checks on scatter-gather tables. This can
  481. help find problems with drivers that do not properly initialize
  482. their sg tables.
  483. If unsure, say N.
  484. config DEBUG_NOTIFIERS
  485. bool "Debug notifier call chains"
  486. depends on DEBUG_KERNEL
  487. help
  488. Enable this to turn on sanity checking for notifier call chains.
  489. This is most useful for kernel developers to make sure that
  490. modules properly unregister themselves from notifier chains.
  491. This is a relatively cheap check but if you care about maximum
  492. performance, say N.
  493. config FRAME_POINTER
  494. bool "Compile the kernel with frame pointers"
  495. depends on DEBUG_KERNEL && \
  496. (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || \
  497. AVR32 || SUPERH || BLACKFIN || MN10300)
  498. default y if DEBUG_INFO && UML
  499. help
  500. If you say Y here the resulting kernel image will be slightly larger
  501. and slower, but it might give very useful debugging information on
  502. some architectures or if you use external debuggers.
  503. If you don't debug the kernel, you can say N.
  504. config BOOT_PRINTK_DELAY
  505. bool "Delay each boot printk message by N milliseconds"
  506. depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
  507. help
  508. This build option allows you to read kernel boot messages
  509. by inserting a short delay after each one. The delay is
  510. specified in milliseconds on the kernel command line,
  511. using "boot_delay=N".
  512. It is likely that you would also need to use "lpj=M" to preset
  513. the "loops per jiffie" value.
  514. See a previous boot log for the "lpj" value to use for your
  515. system, and then set "lpj=M" before setting "boot_delay=N".
  516. NOTE: Using this option may adversely affect SMP systems.
  517. I.e., processors other than the first one may not boot up.
  518. BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
  519. what it believes to be lockup conditions.
  520. config RCU_TORTURE_TEST
  521. tristate "torture tests for RCU"
  522. depends on DEBUG_KERNEL
  523. default n
  524. help
  525. This option provides a kernel module that runs torture tests
  526. on the RCU infrastructure. The kernel module may be built
  527. after the fact on the running kernel to be tested, if desired.
  528. Say Y here if you want RCU torture tests to be built into
  529. the kernel.
  530. Say M if you want the RCU torture tests to build as a module.
  531. Say N if you are unsure.
  532. config RCU_TORTURE_TEST_RUNNABLE
  533. bool "torture tests for RCU runnable by default"
  534. depends on RCU_TORTURE_TEST = y
  535. default n
  536. help
  537. This option provides a way to build the RCU torture tests
  538. directly into the kernel without them starting up at boot
  539. time. You can use /proc/sys/kernel/rcutorture_runnable
  540. to manually override this setting. This /proc file is
  541. available only when the RCU torture tests have been built
  542. into the kernel.
  543. Say Y here if you want the RCU torture tests to start during
  544. boot (you probably don't).
  545. Say N here if you want the RCU torture tests to start only
  546. after being manually enabled via /proc.
  547. config RCU_CPU_STALL_DETECTOR
  548. bool "Check for stalled CPUs delaying RCU grace periods"
  549. depends on CLASSIC_RCU
  550. default n
  551. help
  552. This option causes RCU to printk information on which
  553. CPUs are delaying the current grace period, but only when
  554. the grace period extends for excessive time periods.
  555. Say Y if you want RCU to perform such checks.
  556. Say N if you are unsure.
  557. config RCU_CPU_STALL_DETECTOR
  558. bool "Check for stalled CPUs delaying RCU grace periods"
  559. depends on CLASSIC_RCU || TREE_RCU
  560. default n
  561. help
  562. This option causes RCU to printk information on which
  563. CPUs are delaying the current grace period, but only when
  564. the grace period extends for excessive time periods.
  565. Say Y if you want RCU to perform such checks.
  566. Say N if you are unsure.
  567. config KPROBES_SANITY_TEST
  568. bool "Kprobes sanity tests"
  569. depends on DEBUG_KERNEL
  570. depends on KPROBES
  571. default n
  572. help
  573. This option provides for testing basic kprobes functionality on
  574. boot. A sample kprobe, jprobe and kretprobe are inserted and
  575. verified for functionality.
  576. Say N if you are unsure.
  577. config BACKTRACE_SELF_TEST
  578. tristate "Self test for the backtrace code"
  579. depends on DEBUG_KERNEL
  580. default n
  581. help
  582. This option provides a kernel module that can be used to test
  583. the kernel stack backtrace code. This option is not useful
  584. for distributions or general kernels, but only for kernel
  585. developers working on architecture code.
  586. Note that if you want to also test saved backtraces, you will
  587. have to enable STACKTRACE as well.
  588. Say N if you are unsure.
  589. config DEBUG_BLOCK_EXT_DEVT
  590. bool "Force extended block device numbers and spread them"
  591. depends on DEBUG_KERNEL
  592. depends on BLOCK
  593. default n
  594. help
  595. BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
  596. SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
  597. YOU ARE DOING. Distros, please enable this and fix whatever
  598. is broken.
  599. Conventionally, block device numbers are allocated from
  600. predetermined contiguous area. However, extended block area
  601. may introduce non-contiguous block device numbers. This
  602. option forces most block device numbers to be allocated from
  603. the extended space and spreads them to discover kernel or
  604. userland code paths which assume predetermined contiguous
  605. device number allocation.
  606. Note that turning on this debug option shuffles all the
  607. device numbers for all IDE and SCSI devices including libata
  608. ones, so root partition specified using device number
  609. directly (via rdev or root=MAJ:MIN) won't work anymore.
  610. Textual device names (root=/dev/sdXn) will continue to work.
  611. Say N if you are unsure.
  612. config LKDTM
  613. tristate "Linux Kernel Dump Test Tool Module"
  614. depends on DEBUG_KERNEL
  615. depends on KPROBES
  616. depends on BLOCK
  617. default n
  618. help
  619. This module enables testing of the different dumping mechanisms by
  620. inducing system failures at predefined crash points.
  621. If you don't need it: say N
  622. Choose M here to compile this code as a module. The module will be
  623. called lkdtm.
  624. Documentation on how to use the module can be found in
  625. drivers/misc/lkdtm.c
  626. config FAULT_INJECTION
  627. bool "Fault-injection framework"
  628. depends on DEBUG_KERNEL
  629. help
  630. Provide fault-injection framework.
  631. For more details, see Documentation/fault-injection/.
  632. config FAILSLAB
  633. bool "Fault-injection capability for kmalloc"
  634. depends on FAULT_INJECTION
  635. depends on SLAB || SLUB
  636. help
  637. Provide fault-injection capability for kmalloc.
  638. config FAIL_PAGE_ALLOC
  639. bool "Fault-injection capabilitiy for alloc_pages()"
  640. depends on FAULT_INJECTION
  641. help
  642. Provide fault-injection capability for alloc_pages().
  643. config FAIL_MAKE_REQUEST
  644. bool "Fault-injection capability for disk IO"
  645. depends on FAULT_INJECTION && BLOCK
  646. help
  647. Provide fault-injection capability for disk IO.
  648. config FAIL_IO_TIMEOUT
  649. bool "Faul-injection capability for faking disk interrupts"
  650. depends on FAULT_INJECTION && BLOCK
  651. help
  652. Provide fault-injection capability on end IO handling. This
  653. will make the block layer "forget" an interrupt as configured,
  654. thus exercising the error handling.
  655. Only works with drivers that use the generic timeout handling,
  656. for others it wont do anything.
  657. config FAULT_INJECTION_DEBUG_FS
  658. bool "Debugfs entries for fault-injection capabilities"
  659. depends on FAULT_INJECTION && SYSFS && DEBUG_FS
  660. help
  661. Enable configuration of fault-injection capabilities via debugfs.
  662. config FAULT_INJECTION_STACKTRACE_FILTER
  663. bool "stacktrace filter for fault-injection capabilities"
  664. depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
  665. depends on !X86_64
  666. select STACKTRACE
  667. select FRAME_POINTER if !PPC
  668. help
  669. Provide stacktrace filter for fault-injection capabilities
  670. config LATENCYTOP
  671. bool "Latency measuring infrastructure"
  672. select FRAME_POINTER if !MIPS && !PPC
  673. select KALLSYMS
  674. select KALLSYMS_ALL
  675. select STACKTRACE
  676. select SCHEDSTATS
  677. select SCHED_DEBUG
  678. depends on HAVE_LATENCYTOP_SUPPORT
  679. help
  680. Enable this option if you want to use the LatencyTOP tool
  681. to find out which userspace is blocking on what kernel operations.
  682. config SYSCTL_SYSCALL_CHECK
  683. bool "Sysctl checks"
  684. depends on SYSCTL_SYSCALL
  685. ---help---
  686. sys_sysctl uses binary paths that have been found challenging
  687. to properly maintain and use. This enables checks that help
  688. you to keep things correct.
  689. source kernel/trace/Kconfig
  690. config PROVIDE_OHCI1394_DMA_INIT
  691. bool "Remote debugging over FireWire early on boot"
  692. depends on PCI && X86
  693. help
  694. If you want to debug problems which hang or crash the kernel early
  695. on boot and the crashing machine has a FireWire port, you can use
  696. this feature to remotely access the memory of the crashed machine
  697. over FireWire. This employs remote DMA as part of the OHCI1394
  698. specification which is now the standard for FireWire controllers.
  699. With remote DMA, you can monitor the printk buffer remotely using
  700. firescope and access all memory below 4GB using fireproxy from gdb.
  701. Even controlling a kernel debugger is possible using remote DMA.
  702. Usage:
  703. If ohci1394_dma=early is used as boot parameter, it will initialize
  704. all OHCI1394 controllers which are found in the PCI config space.
  705. As all changes to the FireWire bus such as enabling and disabling
  706. devices cause a bus reset and thereby disable remote DMA for all
  707. devices, be sure to have the cable plugged and FireWire enabled on
  708. the debugging host before booting the debug target for debugging.
  709. This code (~1k) is freed after boot. By then, the firewire stack
  710. in charge of the OHCI-1394 controllers should be used instead.
  711. See Documentation/debugging-via-ohci1394.txt for more information.
  712. config FIREWIRE_OHCI_REMOTE_DMA
  713. bool "Remote debugging over FireWire with firewire-ohci"
  714. depends on FIREWIRE_OHCI
  715. help
  716. This option lets you use the FireWire bus for remote debugging
  717. with help of the firewire-ohci driver. It enables unfiltered
  718. remote DMA in firewire-ohci.
  719. See Documentation/debugging-via-ohci1394.txt for more information.
  720. If unsure, say N.
  721. menuconfig BUILD_DOCSRC
  722. bool "Build targets in Documentation/ tree"
  723. depends on HEADERS_CHECK
  724. help
  725. This option attempts to build objects from the source files in the
  726. kernel Documentation/ tree.
  727. Say N if you are unsure.
  728. config DYNAMIC_PRINTK_DEBUG
  729. bool "Enable dynamic printk() call support"
  730. default n
  731. depends on PRINTK
  732. select PRINTK_DEBUG
  733. help
  734. Compiles debug level messages into the kernel, which would not
  735. otherwise be available at runtime. These messages can then be
  736. enabled/disabled on a per module basis. This mechanism implicitly
  737. enables all pr_debug() and dev_dbg() calls. The impact of this
  738. compile option is a larger kernel text size of about 2%.
  739. Usage:
  740. Dynamic debugging is controlled by the debugfs file,
  741. dynamic_printk/modules. This file contains a list of the modules that
  742. can be enabled. The format of the file is the module name, followed
  743. by a set of flags that can be enabled. The first flag is always the
  744. 'enabled' flag. For example:
  745. <module_name> <enabled=0/1>
  746. .
  747. .
  748. .
  749. <module_name> : Name of the module in which the debug call resides
  750. <enabled=0/1> : whether the messages are enabled or not
  751. From a live system:
  752. snd_hda_intel enabled=0
  753. fixup enabled=0
  754. driver enabled=0
  755. Enable a module:
  756. $echo "set enabled=1 <module_name>" > dynamic_printk/modules
  757. Disable a module:
  758. $echo "set enabled=0 <module_name>" > dynamic_printk/modules
  759. Enable all modules:
  760. $echo "set enabled=1 all" > dynamic_printk/modules
  761. Disable all modules:
  762. $echo "set enabled=0 all" > dynamic_printk/modules
  763. Finally, passing "dynamic_printk" at the command line enables
  764. debugging for all modules. This mode can be turned off via the above
  765. disable command.
  766. source "samples/Kconfig"
  767. source "lib/Kconfig.kgdb"