Merge tag 'v3.10.93' into update
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / lib / Kconfig.debug
CommitLineData
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1
2config PRINTK_TIME
3 bool "Show timing information on printks"
d3b8b6e5 4 depends on PRINTK
1da177e4 5 help
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6 Selecting this option causes time stamps of the printk()
7 messages to be added to the output of the syslog() system
8 call and at the console.
9
10 The timestamp is always recorded internally, and exported
11 to /dev/kmsg. This flag just specifies if the timestamp should
12 be included, not that the timestamp is recorded.
13
14 The behavior is also controlled by the kernel command line
15 parameter printk.time=1. See Documentation/kernel-parameters.txt
1da177e4 16
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17config DEFAULT_MESSAGE_LOGLEVEL
18 int "Default message log level (1-7)"
19 range 1 7
20 default "4"
21 help
22 Default log level for printk statements with no specified priority.
23
24 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
25 that are auditing their logs closely may want to set it to a lower
26 priority.
27
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28config ENABLE_WARN_DEPRECATED
29 bool "Enable __deprecated logic"
30 default y
31 help
32 Enable the __deprecated logic in the kernel build.
33 Disable this to suppress the "warning: 'foo' is deprecated
34 (declared at kernel/power/somefile.c:1234)" messages.
35
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36config ENABLE_MUST_CHECK
37 bool "Enable __must_check logic"
38 default y
39 help
40 Enable the __must_check logic in the kernel build. Disable this to
41 suppress the "warning: ignoring return value of 'foo', declared with
42 attribute warn_unused_result" messages.
1da177e4 43
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44config FRAME_WARN
45 int "Warn for stack frames larger than (needs gcc 4.4)"
46 range 0 8192
47 default 1024 if !64BIT
48 default 2048 if 64BIT
49 help
50 Tell gcc to warn at build time for stack frames larger than this.
51 Setting this too low will cause a lot of warnings.
52 Setting it to 0 disables the warning.
53 Requires gcc 4.4
54
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55config MAGIC_SYSRQ
56 bool "Magic SysRq key"
f346f4b3 57 depends on !UML
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58 help
59 If you say Y here, you will have some control over the system even
60 if the system crashes for example during kernel debugging (e.g., you
61 will be able to flush the buffer cache to disk, reboot the system
62 immediately or dump some status information). This is accomplished
63 by pressing various keys while holding SysRq (Alt+PrintScreen). It
64 also works on a serial console (on PC hardware at least), if you
65 send a BREAK and then within 5 seconds a command keypress. The
66 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
67 unless you really know what this hack does.
68
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69config STRIP_ASM_SYMS
70 bool "Strip assembler-generated symbols during link"
71 default n
72 help
73 Strip internal assembler-generated symbols during a link (symbols
74 that look like '.Lxxx') so they don't pollute the output of
75 get_wchan() and suchlike.
76
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77config READABLE_ASM
78 bool "Generate readable assembler code"
79 depends on DEBUG_KERNEL
80 help
81 Disable some compiler optimizations that tend to generate human unreadable
82 assembler output. This may make the kernel slightly slower, but it helps
83 to keep kernel developers who have to stare a lot at assembler listings
84 sane.
85
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86config UNUSED_SYMBOLS
87 bool "Enable unused/obsolete exported symbols"
88 default y if X86
89 help
90 Unused but exported symbols make the kernel needlessly bigger. For
91 that reason most of these unused exports will soon be removed. This
92 option is provided temporarily to provide a transition period in case
93 some external kernel module needs one of these symbols anyway. If you
94 encounter such a case in your module, consider if you are actually
95 using the right API. (rationale: since nobody in the kernel is using
96 this in a module, there is a pretty good chance it's actually the
97 wrong interface to use). If you really need the symbol, please send a
98 mail to the linux kernel mailing list mentioning the symbol and why
99 you really need it, and what the merge plan to the mainline kernel for
100 your module is.
101
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102config DEBUG_FS
103 bool "Debug Filesystem"
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104 help
105 debugfs is a virtual file system that kernel developers use to put
106 debugging files into. Enable this option to be able to read and
107 write to these files.
108
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109 For detailed documentation on the debugfs API, see
110 Documentation/DocBook/filesystems.
111
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112 If unsure, say N.
113
114config HEADERS_CHECK
115 bool "Run 'make headers_check' when building vmlinux"
116 depends on !UML
117 help
118 This option will extract the user-visible kernel headers whenever
119 building the kernel, and will run basic sanity checks on them to
120 ensure that exported files do not attempt to include files which
121 were not exported, etc.
122
123 If you're making modifications to header files which are
124 relevant for userspace, say 'Y', and check the headers
125 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
126 your build tree), to make sure they're suitable.
127
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128config DEBUG_SECTION_MISMATCH
129 bool "Enable full Section mismatch analysis"
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130 help
131 The section mismatch analysis checks if there are illegal
132 references from one section to another section.
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133 During linktime or runtime, some sections are dropped;
134 any use of code/data previously in these sections would
91341d4b 135 most likely result in an oops.
e809ab01 136 In the code, functions and variables are annotated with
6ae14171 137 __init, __cpuinit, etc. (see the full list in include/linux/init.h),
d6fbfa4f 138 which results in the code/data being placed in specific sections.
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139 The section mismatch analysis is always performed after a full
140 kernel build, and enabling this option causes the following
141 additional steps to occur:
142 - Add the option -fno-inline-functions-called-once to gcc commands.
143 When inlining a function annotated with __init in a non-init
144 function, we would lose the section information and thus
91341d4b 145 the analysis would not catch the illegal reference.
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146 This option tells gcc to inline less (but it does result in
147 a larger kernel).
148 - Run the section mismatch analysis for each module/built-in.o file.
149 When we run the section mismatch analysis on vmlinux.o, we
d6fbfa4f 150 lose valueble information about where the mismatch was
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151 introduced.
152 Running the analysis for each module/built-in.o file
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153 tells where the mismatch happens much closer to the
154 source. The drawback is that the same mismatch is
155 reported at least twice.
156 - Enable verbose reporting from modpost in order to help resolve
157 the section mismatches that are reported.
91341d4b 158
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159config DEBUG_KERNEL
160 bool "Kernel debugging"
161 help
162 Say Y here if you are developing drivers or trying to debug and
163 identify kernel problems.
164
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165config DEBUG_SHIRQ
166 bool "Debug shared IRQ handlers"
167 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
168 help
169 Enable this to generate a spurious interrupt as soon as a shared
170 interrupt handler is registered, and just before one is deregistered.
171 Drivers ought to be able to handle interrupts coming in at those
172 points; some don't and need to be caught.
173
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174config LOCKUP_DETECTOR
175 bool "Detect Hard and Soft Lockups"
dea20a3f 176 depends on DEBUG_KERNEL && !S390
8446f1d3 177 help
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178 Say Y here to enable the kernel to act as a watchdog to detect
179 hard and soft lockups.
180
181 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 182 mode for more than 20 seconds, without giving other tasks a
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183 chance to run. The current stack trace is displayed upon
184 detection and the system will stay locked up.
8446f1d3 185
58687acb 186 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 187 for more than 10 seconds, without letting other interrupts have a
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188 chance to run. The current stack trace is displayed upon detection
189 and the system will stay locked up.
8446f1d3 190
58687acb 191 The overhead should be minimal. A periodic hrtimer runs to
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192 generate interrupts and kick the watchdog task every 4 seconds.
193 An NMI is generated every 10 seconds or so to check for hardlockups.
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194 If NMIs are not available on the platform, every 12 seconds the
195 hrtimer interrupt on one cpu will be used to check for hardlockups
196 on the next cpu.
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197
198 The frequency of hrtimer and NMI events and the soft and hard lockup
199 thresholds can be controlled through the sysctl watchdog_thresh.
8446f1d3 200
6fa3eb70 201config HARDLOCKUP_DETECTOR_NMI
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202 def_bool y
203 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
204 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
8446f1d3 205
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206config HARDLOCKUP_DETECTOR_OTHER_CPU
207 def_bool y
208 depends on LOCKUP_DETECTOR && SMP
209 depends on !HARDLOCKUP_DETECTOR_NMI && !HAVE_NMI_WATCHDOG
210
211config HARDLOCKUP_DETECTOR
212 def_bool y
213 depends on HARDLOCKUP_DETECTOR_NMI || HARDLOCKUP_DETECTOR_OTHER_CPU
214
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215config BOOTPARAM_HARDLOCKUP_PANIC
216 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 217 depends on HARDLOCKUP_DETECTOR
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218 help
219 Say Y here to enable the kernel to panic on "hard lockups",
220 which are bugs that cause the kernel to loop in kernel
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221 mode with interrupts disabled for more than 10 seconds (configurable
222 using the watchdog_thresh sysctl).
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223
224 Say N if unsure.
225
226config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
227 int
8f1f66ed 228 depends on HARDLOCKUP_DETECTOR
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229 range 0 1
230 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
231 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
232
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233config BOOTPARAM_SOFTLOCKUP_PANIC
234 bool "Panic (Reboot) On Soft Lockups"
89d7ce2a 235 depends on LOCKUP_DETECTOR
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236 help
237 Say Y here to enable the kernel to panic on "soft lockups",
238 which are bugs that cause the kernel to loop in kernel
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239 mode for more than 20 seconds (configurable using the watchdog_thresh
240 sysctl), without giving other tasks a chance to run.
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241
242 The panic can be used in combination with panic_timeout,
243 to cause the system to reboot automatically after a
244 lockup has been detected. This feature is useful for
245 high-availability systems that have uptime guarantees and
246 where a lockup must be resolved ASAP.
247
248 Say N if unsure.
249
250config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
251 int
e16bb1d7 252 depends on LOCKUP_DETECTOR
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253 range 0 1
254 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
255 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
256
2a01bb38 257config PANIC_ON_OOPS
76e84026 258 bool "Panic on Oops"
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259 help
260 Say Y here to enable the kernel to panic when it oopses. This
261 has the same effect as setting oops=panic on the kernel command
262 line.
263
264 This feature is useful to ensure that the kernel does not do
265 anything erroneous after an oops which could result in data
266 corruption or other issues.
267
268 Say N if unsure.
269
270config PANIC_ON_OOPS_VALUE
271 int
272 range 0 1
273 default 0 if !PANIC_ON_OOPS
274 default 1 if PANIC_ON_OOPS
275
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276config DETECT_HUNG_TASK
277 bool "Detect Hung Tasks"
278 depends on DEBUG_KERNEL
8edbb83e 279 default LOCKUP_DETECTOR
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280 help
281 Say Y here to enable the kernel to detect "hung tasks",
282 which are bugs that cause the task to be stuck in
283 uninterruptible "D" state indefinitiley.
284
285 When a hung task is detected, the kernel will print the
286 current stack trace (which you should report), but the
287 task will stay in uninterruptible state. If lockdep is
288 enabled then all held locks will also be reported. This
289 feature has negligible overhead.
290
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291config DEFAULT_HUNG_TASK_TIMEOUT
292 int "Default timeout for hung task detection (in seconds)"
293 depends on DETECT_HUNG_TASK
294 default 120
295 help
296 This option controls the default timeout (in seconds) used
297 to determine when a task has become non-responsive and should
298 be considered hung.
299
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300 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
301 sysctl or by writing a value to
302 /proc/sys/kernel/hung_task_timeout_secs.
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303
304 A timeout of 0 disables the check. The default is two minutes.
305 Keeping the default should be fine in most cases.
306
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307config BOOTPARAM_HUNG_TASK_PANIC
308 bool "Panic (Reboot) On Hung Tasks"
309 depends on DETECT_HUNG_TASK
310 help
311 Say Y here to enable the kernel to panic on "hung tasks",
312 which are bugs that cause the kernel to leave a task stuck
313 in uninterruptible "D" state.
314
315 The panic can be used in combination with panic_timeout,
316 to cause the system to reboot automatically after a
317 hung task has been detected. This feature is useful for
318 high-availability systems that have uptime guarantees and
319 where a hung tasks must be resolved ASAP.
320
321 Say N if unsure.
322
323config BOOTPARAM_HUNG_TASK_PANIC_VALUE
324 int
325 depends on DETECT_HUNG_TASK
326 range 0 1
327 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
328 default 1 if BOOTPARAM_HUNG_TASK_PANIC
329
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330config SCHED_DEBUG
331 bool "Collect scheduler debugging info"
332 depends on DEBUG_KERNEL && PROC_FS
333 default y
334 help
335 If you say Y here, the /proc/sched_debug file will be provided
336 that can help debug the scheduler. The runtime overhead of this
337 option is minimal.
338
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339config SCHEDSTATS
340 bool "Collect scheduler statistics"
341 depends on DEBUG_KERNEL && PROC_FS
342 help
343 If you say Y here, additional code will be inserted into the
344 scheduler and related routines to collect statistics about
345 scheduler behavior and provide them in /proc/schedstat. These
346 stats may be useful for both tuning and debugging the scheduler
347 If you aren't debugging the scheduler or trying to tune a specific
348 application, you can say N to avoid the very slight overhead
349 this adds.
350
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351config TIMER_STATS
352 bool "Collect kernel timers statistics"
353 depends on DEBUG_KERNEL && PROC_FS
354 help
355 If you say Y here, additional code will be inserted into the
356 timer routines to collect statistics about kernel timers being
357 reprogrammed. The statistics can be read from /proc/timer_stats.
358 The statistics collection is started by writing 1 to /proc/timer_stats,
359 writing 0 stops it. This feature is useful to collect information
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360 about timer usage patterns in kernel and userspace. This feature
361 is lightweight if enabled in the kernel config but not activated
362 (it defaults to deactivated on bootup and will only be activated
363 if some application like powertop activates it explicitly).
82f67cd9 364
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365config DEBUG_OBJECTS
366 bool "Debug object operations"
367 depends on DEBUG_KERNEL
368 help
369 If you say Y here, additional code will be inserted into the
370 kernel to track the life time of various objects and validate
371 the operations on those objects.
372
373config DEBUG_OBJECTS_SELFTEST
374 bool "Debug objects selftest"
375 depends on DEBUG_OBJECTS
376 help
377 This enables the selftest of the object debug code.
378
379config DEBUG_OBJECTS_FREE
380 bool "Debug objects in freed memory"
381 depends on DEBUG_OBJECTS
382 help
383 This enables checks whether a k/v free operation frees an area
384 which contains an object which has not been deactivated
385 properly. This can make kmalloc/kfree-intensive workloads
386 much slower.
387
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388config DEBUG_OBJECTS_TIMERS
389 bool "Debug timer objects"
390 depends on DEBUG_OBJECTS
391 help
392 If you say Y here, additional code will be inserted into the
393 timer routines to track the life time of timer objects and
394 validate the timer operations.
395
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396config DEBUG_OBJECTS_WORK
397 bool "Debug work objects"
398 depends on DEBUG_OBJECTS
399 help
400 If you say Y here, additional code will be inserted into the
401 work queue routines to track the life time of work objects and
402 validate the work operations.
403
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404config DEBUG_OBJECTS_RCU_HEAD
405 bool "Debug RCU callbacks objects"
fc2ecf7e 406 depends on DEBUG_OBJECTS
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407 help
408 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
409
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410config DEBUG_OBJECTS_PERCPU_COUNTER
411 bool "Debug percpu counter objects"
412 depends on DEBUG_OBJECTS
413 help
414 If you say Y here, additional code will be inserted into the
415 percpu counter routines to track the life time of percpu counter
416 objects and validate the percpu counter operations.
417
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418config DEBUG_OBJECTS_ENABLE_DEFAULT
419 int "debug_objects bootup default value (0-1)"
420 range 0 1
421 default "1"
422 depends on DEBUG_OBJECTS
423 help
424 Debug objects boot parameter default value
425
1da177e4 426config DEBUG_SLAB
4a2f0acf 427 bool "Debug slab memory allocations"
7d46d9e6 428 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
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429 help
430 Say Y here to have the kernel do limited verification on memory
431 allocation as well as poisoning memory on free to catch use of freed
432 memory. This can make kmalloc/kfree-intensive workloads much slower.
433
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434config DEBUG_SLAB_LEAK
435 bool "Memory leak debugging"
436 depends on DEBUG_SLAB
437
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438config SLUB_DEBUG_ON
439 bool "SLUB debugging on by default"
7d46d9e6 440 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
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441 default n
442 help
443 Boot with debugging on by default. SLUB boots by default with
444 the runtime debug capabilities switched off. Enabling this is
445 equivalent to specifying the "slub_debug" parameter on boot.
446 There is no support for more fine grained debug control like
447 possible with slub_debug=xxx. SLUB debugging may be switched
448 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
449 "slub_debug=-".
450
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451config SLUB_STATS
452 default n
453 bool "Enable SLUB performance statistics"
ab4d5ed5 454 depends on SLUB && SYSFS
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455 help
456 SLUB statistics are useful to debug SLUBs allocation behavior in
457 order find ways to optimize the allocator. This should never be
458 enabled for production use since keeping statistics slows down
459 the allocator by a few percentage points. The slabinfo command
460 supports the determination of the most active slabs to figure
461 out which slabs are relevant to a particular load.
462 Try running: slabinfo -DA
463
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464config HAVE_DEBUG_KMEMLEAK
465 bool
466
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467config DEBUG_KMEMLEAK
468 bool "Kernel memory leak detector"
525c1f92 469 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 470 select DEBUG_FS
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471 select STACKTRACE if STACKTRACE_SUPPORT
472 select KALLSYMS
b60e26a2 473 select CRC32
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474 help
475 Say Y here if you want to enable the memory leak
476 detector. The memory allocation/freeing is traced in a way
477 similar to the Boehm's conservative garbage collector, the
478 difference being that the orphan objects are not freed but
479 only shown in /sys/kernel/debug/kmemleak. Enabling this
480 feature will introduce an overhead to memory
481 allocations. See Documentation/kmemleak.txt for more
482 details.
483
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484 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
485 of finding leaks due to the slab objects poisoning.
486
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487 In order to access the kmemleak file, debugfs needs to be
488 mounted (usually at /sys/kernel/debug).
489
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490config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
491 int "Maximum kmemleak early log entries"
492 depends on DEBUG_KMEMLEAK
dfcc3e6a 493 range 200 40000
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494 default 400
495 help
496 Kmemleak must track all the memory allocations to avoid
497 reporting false positives. Since memory may be allocated or
498 freed before kmemleak is initialised, an early log buffer is
499 used to store these actions. If kmemleak reports "early log
500 buffer exceeded", please increase this value.
501
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502config DEBUG_KMEMLEAK_TEST
503 tristate "Simple test for the kernel memory leak detector"
9718269a 504 depends on DEBUG_KMEMLEAK && m
0822ee4a 505 help
9718269a 506 This option enables a module that explicitly leaks memory.
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507
508 If unsure, say N.
509
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510config DEBUG_KMEMLEAK_DEFAULT_OFF
511 bool "Default kmemleak to off"
512 depends on DEBUG_KMEMLEAK
513 help
514 Say Y here to disable kmemleak by default. It can then be enabled
515 on the command line via kmemleak=on.
516
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517config DEBUG_PREEMPT
518 bool "Debug preemptible kernel"
01deab98 519 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
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520 default y
521 help
522 If you say Y here then the kernel will use a debug variant of the
523 commonly used smp_processor_id() function and will print warnings
524 if kernel code uses it in a preemption-unsafe way. Also, the kernel
525 will detect preemption count underflows.
526
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527config DEBUG_RT_MUTEXES
528 bool "RT Mutex debugging, deadlock detection"
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529 depends on DEBUG_KERNEL && RT_MUTEXES
530 help
531 This allows rt mutex semantics violations and rt mutex related
532 deadlocks (lockups) to be detected and reported automatically.
533
534config DEBUG_PI_LIST
535 bool
536 default y
537 depends on DEBUG_RT_MUTEXES
538
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539config RT_MUTEX_TESTER
540 bool "Built-in scriptable tester for rt-mutexes"
a1583d3e 541 depends on DEBUG_KERNEL && RT_MUTEXES
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542 help
543 This option enables a rt-mutex tester.
544
1da177e4 545config DEBUG_SPINLOCK
4d9f34ad 546 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 547 depends on DEBUG_KERNEL
e335e3eb 548 select UNINLINE_SPIN_UNLOCK
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549 help
550 Say Y here and build SMP to catch missing spinlock initialization
551 and certain other kinds of spinlock errors commonly made. This is
552 best used in conjunction with the NMI watchdog so that spinlock
553 deadlocks are also debuggable.
554
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555config DEBUG_MUTEXES
556 bool "Mutex debugging: basic checks"
557 depends on DEBUG_KERNEL
558 help
559 This feature allows mutex semantics violations to be detected and
560 reported.
561
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562config DEBUG_LOCK_ALLOC
563 bool "Lock debugging: detect incorrect freeing of live locks"
517e7aa5 564 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
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565 select DEBUG_SPINLOCK
566 select DEBUG_MUTEXES
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567 select LOCKDEP
568 help
569 This feature will check whether any held lock (spinlock, rwlock,
570 mutex or rwsem) is incorrectly freed by the kernel, via any of the
571 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
572 vfree(), etc.), whether a live lock is incorrectly reinitialized via
573 spin_lock_init()/mutex_init()/etc., or whether there is any lock
574 held during task exit.
575
576config PROVE_LOCKING
577 bool "Lock debugging: prove locking correctness"
517e7aa5 578 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
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579 select LOCKDEP
580 select DEBUG_SPINLOCK
581 select DEBUG_MUTEXES
4d9f34ad 582 select DEBUG_LOCK_ALLOC
46b93b74 583 select TRACE_IRQFLAGS
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584 default n
585 help
586 This feature enables the kernel to prove that all locking
587 that occurs in the kernel runtime is mathematically
588 correct: that under no circumstance could an arbitrary (and
589 not yet triggered) combination of observed locking
590 sequences (on an arbitrary number of CPUs, running an
591 arbitrary number of tasks and interrupt contexts) cause a
592 deadlock.
593
594 In short, this feature enables the kernel to report locking
595 related deadlocks before they actually occur.
596
597 The proof does not depend on how hard and complex a
598 deadlock scenario would be to trigger: how many
599 participant CPUs, tasks and irq-contexts would be needed
600 for it to trigger. The proof also does not depend on
601 timing: if a race and a resulting deadlock is possible
602 theoretically (no matter how unlikely the race scenario
603 is), it will be proven so and will immediately be
604 reported by the kernel (once the event is observed that
605 makes the deadlock theoretically possible).
606
607 If a deadlock is impossible (i.e. the locking rules, as
608 observed by the kernel, are mathematically correct), the
609 kernel reports nothing.
610
611 NOTE: this feature can also be enabled for rwlocks, mutexes
612 and rwsems - in which case all dependencies between these
613 different locking variants are observed and mapped too, and
614 the proof of observed correctness is also maintained for an
615 arbitrary combination of these separate locking variants.
616
617 For more details, see Documentation/lockdep-design.txt.
618
619config LOCKDEP
620 bool
517e7aa5 621 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
4d9f34ad 622 select STACKTRACE
79aac889 623 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE
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624 select KALLSYMS
625 select KALLSYMS_ALL
626
f20786ff 627config LOCK_STAT
fdfb870f 628 bool "Lock usage statistics"
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629 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
630 select LOCKDEP
631 select DEBUG_SPINLOCK
632 select DEBUG_MUTEXES
633 select DEBUG_LOCK_ALLOC
634 default n
635 help
636 This feature enables tracking lock contention points
637
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638 For more details, see Documentation/lockstat.txt
639
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640 This also enables lock events required by "perf lock",
641 subcommand of perf.
642 If you want to use "perf lock", you also need to turn on
643 CONFIG_EVENT_TRACING.
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644
645 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
dd8b1cf6 646 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
84c6f88f 647
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648config DEBUG_LOCKDEP
649 bool "Lock dependency engine debugging"
517e7aa5 650 depends on DEBUG_KERNEL && LOCKDEP
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651 help
652 If you say Y here, the lock dependency engine will do
653 additional runtime checks to debug itself, at the price
654 of more runtime overhead.
655
656config TRACE_IRQFLAGS
657 bool
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658 help
659 Enables hooks to interrupt enabling and disabling for
660 either tracing or lock debugging.
4d9f34ad 661
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662config DEBUG_ATOMIC_SLEEP
663 bool "Sleep inside atomic section checking"
e8f7c70f 664 select PREEMPT_COUNT
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665 depends on DEBUG_KERNEL
666 help
667 If you say Y here, various routines which may sleep will become very
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668 noisy if they are called inside atomic sections: when a spinlock is
669 held, inside an rcu read side critical section, inside preempt disabled
670 sections, inside an interrupt, etc...
1da177e4 671
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672config DEBUG_LOCKING_API_SELFTESTS
673 bool "Locking API boot-time self-tests"
674 depends on DEBUG_KERNEL
675 help
676 Say Y here if you want the kernel to run a short self-test during
677 bootup. The self-test checks whether common types of locking bugs
678 are detected by debugging mechanisms or not. (if you disable
679 lock debugging then those bugs wont be detected of course.)
680 The following locking APIs are covered: spinlocks, rwlocks,
681 mutexes and rwsems.
682
8637c099 683config STACKTRACE
6fa3eb70 684 bool "Stacktrace"
8637c099 685 depends on STACKTRACE_SUPPORT
6fa3eb70 686 default y
8637c099 687
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688config DEBUG_STACK_USAGE
689 bool "Stack utilization instrumentation"
79f83c02 690 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
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SB
691 help
692 Enables the display of the minimum amount of free stack which each
693 task has ever had available in the sysrq-T and sysrq-P debug output.
694
695 This option will slow down process creation somewhat.
696
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697config DEBUG_KOBJECT
698 bool "kobject debugging"
699 depends on DEBUG_KERNEL
700 help
701 If you say Y here, some extra kobject debugging messages will be sent
702 to the syslog.
703
704config DEBUG_HIGHMEM
705 bool "Highmem debugging"
706 depends on DEBUG_KERNEL && HIGHMEM
707 help
708 This options enables addition error checking for high memory systems.
709 Disable for production systems.
710
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711config HAVE_DEBUG_BUGVERBOSE
712 bool
713
1da177e4 714config DEBUG_BUGVERBOSE
6a108a14 715 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
9b2a60c4 716 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
8420e7ef 717 default y
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718 help
719 Say Y here to make BUG() panics output the file name and line number
720 of the BUG call as well as the EIP and oops trace. This aids
721 debugging but costs about 70-100K of memory.
722
723config DEBUG_INFO
724 bool "Compile the kernel with debug info"
725 depends on DEBUG_KERNEL
726 help
727 If you say Y here the resulting kernel image will include
728 debugging info resulting in a larger kernel image.
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729 This adds debug symbols to the kernel and modules (gcc -g), and
730 is needed if you intend to use kernel crashdump or binary object
731 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
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732 Say Y here only if you plan to debug the kernel.
733
734 If unsure, say N.
735
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736config DEBUG_INFO_REDUCED
737 bool "Reduce debugging information"
738 depends on DEBUG_INFO
739 help
740 If you say Y here gcc is instructed to generate less debugging
741 information for structure types. This means that tools that
742 need full debugging information (like kgdb or systemtap) won't
743 be happy. But if you merely need debugging information to
744 resolve line numbers there is no loss. Advantage is that
745 build directory object sizes shrink dramatically over a full
746 DEBUG_INFO build and compile times are reduced too.
747 Only works with newer gcc versions.
748
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749config DEBUG_VM
750 bool "Debug VM"
751 depends on DEBUG_KERNEL
752 help
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753 Enable this to turn on extended checks in the virtual-memory system
754 that may impact performance.
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755
756 If unsure, say N.
757
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758config DEBUG_VM_RB
759 bool "Debug VM red-black trees"
760 depends on DEBUG_VM
761 help
762 Enable this to turn on more extended checks in the virtual-memory
763 system that may impact performance.
764
765 If unsure, say N.
766
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767config DEBUG_VIRTUAL
768 bool "Debug VM translations"
769 depends on DEBUG_KERNEL && X86
770 help
771 Enable some costly sanity checks in virtual to page code. This can
772 catch mistakes with virt_to_page() and friends.
773
774 If unsure, say N.
775
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776config DEBUG_NOMMU_REGIONS
777 bool "Debug the global anon/private NOMMU mapping region tree"
778 depends on DEBUG_KERNEL && !MMU
779 help
780 This option causes the global tree of anonymous and private mapping
781 regions to be regularly checked for invalid topology.
782
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783config DEBUG_WRITECOUNT
784 bool "Debug filesystem writers count"
785 depends on DEBUG_KERNEL
786 help
787 Enable this to catch wrong use of the writers count in struct
788 vfsmount. This will increase the size of each file struct by
789 32 bits.
790
791 If unsure, say N.
792
6b74ab97 793config DEBUG_MEMORY_INIT
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794 bool "Debug memory initialisation" if EXPERT
795 default !EXPERT
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796 help
797 Enable this for additional checks during memory initialisation.
798 The sanity checks verify aspects of the VM such as the memory model
799 and other information provided by the architecture. Verbose
800 information will be printed at KERN_DEBUG loglevel depending
801 on the mminit_loglevel= command-line option.
802
803 If unsure, say Y
804
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805config DEBUG_LIST
806 bool "Debug linked list manipulation"
807 depends on DEBUG_KERNEL
808 help
809 Enable this to turn on extended checks in the linked-list
810 walking routines.
811
812 If unsure, say N.
813
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814config TEST_LIST_SORT
815 bool "Linked list sorting test"
816 depends on DEBUG_KERNEL
817 help
818 Enable this to turn on 'list_sort()' function test. This test is
819 executed only once during system boot, so affects only boot time.
820
821 If unsure, say N.
822
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823config DEBUG_SG
824 bool "Debug SG table operations"
825 depends on DEBUG_KERNEL
826 help
827 Enable this to turn on checks on scatter-gather tables. This can
828 help find problems with drivers that do not properly initialize
829 their sg tables.
830
831 If unsure, say N.
832
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833config DEBUG_NOTIFIERS
834 bool "Debug notifier call chains"
835 depends on DEBUG_KERNEL
836 help
837 Enable this to turn on sanity checking for notifier call chains.
838 This is most useful for kernel developers to make sure that
839 modules properly unregister themselves from notifier chains.
840 This is a relatively cheap check but if you care about maximum
841 performance, say N.
842
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843config DEBUG_CREDENTIALS
844 bool "Debug credential management"
845 depends on DEBUG_KERNEL
846 help
847 Enable this to turn on some debug checking for credential
848 management. The additional code keeps track of the number of
849 pointers from task_structs to any given cred struct, and checks to
850 see that this number never exceeds the usage count of the cred
851 struct.
852
853 Furthermore, if SELinux is enabled, this also checks that the
854 security pointer in the cred struct is never seen to be invalid.
855
856 If unsure, say N.
857
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858#
859# Select this config option from the architecture Kconfig, if it
52288b66 860# is preferred to always offer frame pointers as a config
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JM
861# option on the architecture (regardless of KERNEL_DEBUG):
862#
863config ARCH_WANT_FRAME_POINTERS
864 bool
865 help
866
1da177e4
LT
867config FRAME_POINTER
868 bool "Compile the kernel with frame pointers"
b920de1b 869 depends on DEBUG_KERNEL && \
73020415 870 (CRIS || M68K || FRV || UML || \
79f83c02 871 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
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872 ARCH_WANT_FRAME_POINTERS
873 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
874 help
875 If you say Y here the resulting kernel image will be slightly
876 larger and slower, but it gives very useful debugging information
877 in case of kernel bugs. (precise oopses/stacktraces/warnings)
1da177e4 878
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879config BOOT_PRINTK_DELAY
880 bool "Delay each boot printk message by N milliseconds"
881 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
882 help
883 This build option allows you to read kernel boot messages
884 by inserting a short delay after each one. The delay is
885 specified in milliseconds on the kernel command line,
886 using "boot_delay=N".
887
888 It is likely that you would also need to use "lpj=M" to preset
889 the "loops per jiffie" value.
890 See a previous boot log for the "lpj" value to use for your
891 system, and then set "lpj=M" before setting "boot_delay=N".
892 NOTE: Using this option may adversely affect SMP systems.
893 I.e., processors other than the first one may not boot up.
8edbb83e 894 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
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RD
895 what it believes to be lockup conditions.
896
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DH
897menu "RCU Debugging"
898
899config PROVE_RCU
900 bool "RCU debugging: prove RCU correctness"
901 depends on PROVE_LOCKING
902 default n
903 help
904 This feature enables lockdep extensions that check for correct
905 use of RCU APIs. This is currently under development. Say Y
906 if you want to debug RCU usage or help work on the PROVE_RCU
907 feature.
908
909 Say N if you are unsure.
910
911config PROVE_RCU_REPEATEDLY
912 bool "RCU debugging: don't disable PROVE_RCU on first splat"
913 depends on PROVE_RCU
914 default n
915 help
916 By itself, PROVE_RCU will disable checking upon issuing the
917 first warning (or "splat"). This feature prevents such
918 disabling, allowing multiple RCU-lockdep warnings to be printed
919 on a single reboot.
920
921 Say Y to allow multiple RCU-lockdep warnings per boot.
922
923 Say N if you are unsure.
924
925config PROVE_RCU_DELAY
926 bool "RCU debugging: preemptible RCU race provocation"
927 depends on DEBUG_KERNEL && PREEMPT_RCU
928 default n
929 help
930 There is a class of races that involve an unlikely preemption
931 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
932 been set to INT_MIN. This feature inserts a delay at that
933 point to increase the probability of these races.
934
935 Say Y to increase probability of preemption of __rcu_read_unlock().
936
937 Say N if you are unsure.
938
939config SPARSE_RCU_POINTER
940 bool "RCU debugging: sparse-based checks for pointer usage"
941 default n
942 help
943 This feature enables the __rcu sparse annotation for
944 RCU-protected pointers. This annotation will cause sparse
945 to flag any non-RCU used of annotated pointers. This can be
946 helpful when debugging RCU usage. Please note that this feature
947 is not intended to enforce code cleanliness; it is instead merely
948 a debugging aid.
949
950 Say Y to make sparse flag questionable use of RCU-protected pointers
951
952 Say N if you are unsure.
953
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954config RCU_TORTURE_TEST
955 tristate "torture tests for RCU"
956 depends on DEBUG_KERNEL
957 default n
958 help
959 This option provides a kernel module that runs torture tests
960 on the RCU infrastructure. The kernel module may be built
961 after the fact on the running kernel to be tested, if desired.
962
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PM
963 Say Y here if you want RCU torture tests to be built into
964 the kernel.
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PM
965 Say M if you want the RCU torture tests to build as a module.
966 Say N if you are unsure.
8bb31b9d 967
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PM
968config RCU_TORTURE_TEST_RUNNABLE
969 bool "torture tests for RCU runnable by default"
970 depends on RCU_TORTURE_TEST = y
971 default n
972 help
973 This option provides a way to build the RCU torture tests
974 directly into the kernel without them starting up at boot
975 time. You can use /proc/sys/kernel/rcutorture_runnable
976 to manually override this setting. This /proc file is
977 available only when the RCU torture tests have been built
978 into the kernel.
979
980 Say Y here if you want the RCU torture tests to start during
981 boot (you probably don't).
982 Say N here if you want the RCU torture tests to start only
983 after being manually enabled via /proc.
984
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985config RCU_CPU_STALL_TIMEOUT
986 int "RCU CPU stall timeout in seconds"
6bfc09e2 987 depends on RCU_STALL_COMMON
b163760e 988 range 3 300
c896054f 989 default 21
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990 help
991 If a given RCU grace period extends more than the specified
992 number of seconds, a CPU stall warning is printed. If the
993 RCU grace period persists, additional CPU stall warnings are
994 printed at more widely spaced intervals.
995
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996config RCU_CPU_STALL_VERBOSE
997 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
a00e0d71 998 depends on TREE_PREEMPT_RCU
55ec936f 999 default y
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PM
1000 help
1001 This option causes RCU to printk detailed per-task information
1002 for any tasks that are stalling the current RCU grace period.
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PM
1003
1004 Say N if you are unsure.
1005
1ed509a2
PM
1006 Say Y if you want to enable such checks.
1007
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1008config RCU_CPU_STALL_INFO
1009 bool "Print additional diagnostics on RCU CPU stall"
1010 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1011 default n
1012 help
1013 For each stalled CPU that is aware of the current RCU grace
1014 period, print out additional per-CPU diagnostic information
1015 regarding scheduling-clock ticks, idle state, and,
1016 for RCU_FAST_NO_HZ kernels, idle-entry state.
1017
1018 Say N if you are unsure.
1019
1020 Say Y if you want to enable such diagnostics.
1021
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PM
1022config RCU_TRACE
1023 bool "Enable tracing for RCU"
1024 depends on DEBUG_KERNEL
52494535 1025 select TRACE_CLOCK
5c8806a0
PM
1026 help
1027 This option provides tracing in RCU which presents stats
1028 in debugfs for debugging RCU implementation.
1029
1030 Say Y here if you want to enable RCU tracing
1031 Say N if you are unsure.
1032
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DH
1033endmenu # "RCU Debugging"
1034
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AM
1035config KPROBES_SANITY_TEST
1036 bool "Kprobes sanity tests"
1037 depends on DEBUG_KERNEL
1038 depends on KPROBES
1039 default n
1040 help
1041 This option provides for testing basic kprobes functionality on
1042 boot. A sample kprobe, jprobe and kretprobe are inserted and
1043 verified for functionality.
1044
1045 Say N if you are unsure.
1046
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AV
1047config BACKTRACE_SELF_TEST
1048 tristate "Self test for the backtrace code"
1049 depends on DEBUG_KERNEL
1050 default n
1051 help
1052 This option provides a kernel module that can be used to test
1053 the kernel stack backtrace code. This option is not useful
1054 for distributions or general kernels, but only for kernel
1055 developers working on architecture code.
1056
ad118c54
VN
1057 Note that if you want to also test saved backtraces, you will
1058 have to enable STACKTRACE as well.
1059
6dab2778
AV
1060 Say N if you are unsure.
1061
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TH
1062config DEBUG_BLOCK_EXT_DEVT
1063 bool "Force extended block device numbers and spread them"
1064 depends on DEBUG_KERNEL
1065 depends on BLOCK
759f8ca3 1066 default n
870d6656 1067 help
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TH
1068 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1069 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1070 YOU ARE DOING. Distros, please enable this and fix whatever
1071 is broken.
1072
870d6656
TH
1073 Conventionally, block device numbers are allocated from
1074 predetermined contiguous area. However, extended block area
1075 may introduce non-contiguous block device numbers. This
1076 option forces most block device numbers to be allocated from
1077 the extended space and spreads them to discover kernel or
1078 userland code paths which assume predetermined contiguous
1079 device number allocation.
1080
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TH
1081 Note that turning on this debug option shuffles all the
1082 device numbers for all IDE and SCSI devices including libata
1083 ones, so root partition specified using device number
1084 directly (via rdev or root=MAJ:MIN) won't work anymore.
1085 Textual device names (root=/dev/sdXn) will continue to work.
1086
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TH
1087 Say N if you are unsure.
1088
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TH
1089config DEBUG_FORCE_WEAK_PER_CPU
1090 bool "Force weak per-cpu definitions"
1091 depends on DEBUG_KERNEL
1092 help
1093 s390 and alpha require percpu variables in modules to be
1094 defined weak to work around addressing range issue which
1095 puts the following two restrictions on percpu variable
1096 definitions.
1097
1098 1. percpu symbols must be unique whether static or not
1099 2. percpu variables can't be defined inside a function
1100
1101 To ensure that generic code follows the above rules, this
1102 option forces all percpu variables to be defined as weak.
1103
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1104config DEBUG_PER_CPU_MAPS
1105 bool "Debug access to per_cpu maps"
1106 depends on DEBUG_KERNEL
1107 depends on SMP
1108 help
1109 Say Y to verify that the per_cpu map being accessed has
1110 been set up. This adds a fair amount of code to kernel memory
1111 and decreases performance.
1112
1113 Say N if unsure.
1114
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AG
1115config LKDTM
1116 tristate "Linux Kernel Dump Test Tool Module"
0347af4e 1117 depends on DEBUG_FS
fddd9cf8 1118 depends on BLOCK
8bb31b9d
AG
1119 default n
1120 help
1121 This module enables testing of the different dumping mechanisms by
1122 inducing system failures at predefined crash points.
1123 If you don't need it: say N
1124 Choose M here to compile this code as a module. The module will be
1125 called lkdtm.
1126
1127 Documentation on how to use the module can be found in
0347af4e 1128 Documentation/fault-injection/provoke-crashes.txt
6ff1cb35 1129
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1130config NOTIFIER_ERROR_INJECTION
1131 tristate "Notifier error injection"
1132 depends on DEBUG_KERNEL
1133 select DEBUG_FS
1134 help
e41e85cc 1135 This option provides the ability to inject artificial errors to
8d438288
AM
1136 specified notifier chain callbacks. It is useful to test the error
1137 handling of notifier call chain failures.
1138
1139 Say N if unsure.
1140
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AM
1141config CPU_NOTIFIER_ERROR_INJECT
1142 tristate "CPU notifier error injection module"
f5a9f52e 1143 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
c9d221f8
AM
1144 help
1145 This option provides a kernel module that can be used to test
e41e85cc 1146 the error handling of the cpu notifiers by injecting artificial
f5a9f52e
AM
1147 errors to CPU notifier chain callbacks. It is controlled through
1148 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1149
1150 If the notifier call chain should be failed with some events
1151 notified, write the error code to "actions/<notifier event>/error".
1152
1153 Example: Inject CPU offline error (-1 == -EPERM)
1154
1155 # cd /sys/kernel/debug/notifier-error-inject/cpu
1156 # echo -1 > actions/CPU_DOWN_PREPARE/error
1157 # echo 0 > /sys/devices/system/cpu/cpu1/online
1158 bash: echo: write error: Operation not permitted
c9d221f8
AM
1159
1160 To compile this code as a module, choose M here: the module will
1161 be called cpu-notifier-error-inject.
1162
1163 If unsure, say N.
1164
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AM
1165config PM_NOTIFIER_ERROR_INJECT
1166 tristate "PM notifier error injection module"
1167 depends on PM && NOTIFIER_ERROR_INJECTION
1168 default m if PM_DEBUG
1169 help
e41e85cc 1170 This option provides the ability to inject artificial errors to
048b9c35
AM
1171 PM notifier chain callbacks. It is controlled through debugfs
1172 interface /sys/kernel/debug/notifier-error-inject/pm
1173
1174 If the notifier call chain should be failed with some events
1175 notified, write the error code to "actions/<notifier event>/error".
1176
1177 Example: Inject PM suspend error (-12 = -ENOMEM)
1178
1179 # cd /sys/kernel/debug/notifier-error-inject/pm/
1180 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1181 # echo mem > /sys/power/state
1182 bash: echo: write error: Cannot allocate memory
1183
1184 To compile this code as a module, choose M here: the module will
1185 be called pm-notifier-error-inject.
1186
1187 If unsure, say N.
1188
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1189config MEMORY_NOTIFIER_ERROR_INJECT
1190 tristate "Memory hotplug notifier error injection module"
1191 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
1192 help
e41e85cc 1193 This option provides the ability to inject artificial errors to
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AM
1194 memory hotplug notifier chain callbacks. It is controlled through
1195 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
1196
1197 If the notifier call chain should be failed with some events
1198 notified, write the error code to "actions/<notifier event>/error".
1199
1200 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
1201
1202 # cd /sys/kernel/debug/notifier-error-inject/memory
1203 # echo -12 > actions/MEM_GOING_OFFLINE/error
1204 # echo offline > /sys/devices/system/memory/memoryXXX/state
1205 bash: echo: write error: Cannot allocate memory
1206
1207 To compile this code as a module, choose M here: the module will
e12a95f4 1208 be called memory-notifier-error-inject.
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AM
1209
1210 If unsure, say N.
1211
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1212config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1213 tristate "OF reconfig notifier error injection module"
1214 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1215 help
e41e85cc 1216 This option provides the ability to inject artificial errors to
d526e85f 1217 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1218 through debugfs interface under
d526e85f 1219 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
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AM
1220
1221 If the notifier call chain should be failed with some events
1222 notified, write the error code to "actions/<notifier event>/error".
1223
1224 To compile this code as a module, choose M here: the module will
e12a95f4 1225 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1226
1227 If unsure, say N.
1228
6ff1cb35 1229config FAULT_INJECTION
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1230 bool "Fault-injection framework"
1231 depends on DEBUG_KERNEL
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AM
1232 help
1233 Provide fault-injection framework.
1234 For more details, see Documentation/fault-injection/.
6ff1cb35 1235
8a8b6502 1236config FAILSLAB
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1237 bool "Fault-injection capability for kmalloc"
1238 depends on FAULT_INJECTION
773ff60e 1239 depends on SLAB || SLUB
8a8b6502 1240 help
1ab8509a 1241 Provide fault-injection capability for kmalloc.
8a8b6502 1242
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AM
1243config FAIL_PAGE_ALLOC
1244 bool "Fault-injection capabilitiy for alloc_pages()"
1ab8509a 1245 depends on FAULT_INJECTION
933e312e 1246 help
1ab8509a 1247 Provide fault-injection capability for alloc_pages().
933e312e 1248
c17bb495 1249config FAIL_MAKE_REQUEST
86327d19 1250 bool "Fault-injection capability for disk IO"
581d4e28 1251 depends on FAULT_INJECTION && BLOCK
c17bb495 1252 help
1ab8509a 1253 Provide fault-injection capability for disk IO.
c17bb495 1254
581d4e28 1255config FAIL_IO_TIMEOUT
f4d01439 1256 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1257 depends on FAULT_INJECTION && BLOCK
1258 help
1259 Provide fault-injection capability on end IO handling. This
1260 will make the block layer "forget" an interrupt as configured,
1261 thus exercising the error handling.
1262
1263 Only works with drivers that use the generic timeout handling,
1264 for others it wont do anything.
1265
1b676f70
PF
1266config FAIL_MMC_REQUEST
1267 bool "Fault-injection capability for MMC IO"
1268 select DEBUG_FS
1269 depends on FAULT_INJECTION && MMC
1270 help
1271 Provide fault-injection capability for MMC IO.
1272 This will make the mmc core return data errors. This is
1273 useful to test the error handling in the mmc block device
1274 and to test how the mmc host driver handles retries from
1275 the block device.
1276
6ff1cb35
AM
1277config FAULT_INJECTION_DEBUG_FS
1278 bool "Debugfs entries for fault-injection capabilities"
1ab8509a 1279 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
6ff1cb35 1280 help
1ab8509a 1281 Enable configuration of fault-injection capabilities via debugfs.
1df49008
AM
1282
1283config FAULT_INJECTION_STACKTRACE_FILTER
1284 bool "stacktrace filter for fault-injection capabilities"
1285 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1286 depends on !X86_64
1df49008 1287 select STACKTRACE
3c19c4f9 1288 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
1df49008
AM
1289 help
1290 Provide stacktrace filter for fault-injection capabilities
267c4025 1291
9745512c
AV
1292config LATENCYTOP
1293 bool "Latency measuring infrastructure"
625fdcaa
RD
1294 depends on HAVE_LATENCYTOP_SUPPORT
1295 depends on DEBUG_KERNEL
1296 depends on STACKTRACE_SUPPORT
1297 depends on PROC_FS
89bace65 1298 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND
9745512c
AV
1299 select KALLSYMS
1300 select KALLSYMS_ALL
1301 select STACKTRACE
1302 select SCHEDSTATS
1303 select SCHED_DEBUG
9745512c
AV
1304 help
1305 Enable this option if you want to use the LatencyTOP tool
1306 to find out which userspace is blocking on what kernel operations.
1307
446f24d1
SB
1308config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1309 bool
1310
1311config DEBUG_STRICT_USER_COPY_CHECKS
1312 bool "Strict user copy size checks"
1313 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1314 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1315 help
1316 Enabling this option turns a certain set of sanity checks for user
1317 copy operations into compile time failures.
1318
1319 The copy_from_user() etc checks are there to help test if there
1320 are sufficient security checks on the length argument of
1321 the copy operation, by having gcc prove that the argument is
1322 within bounds.
1323
1324 If unsure, say N.
1325
6a11f75b 1326source mm/Kconfig.debug
16444a8a
ACM
1327source kernel/trace/Kconfig
1328
910a742d
ML
1329config RBTREE_TEST
1330 tristate "Red-Black tree test"
1331 depends on m && DEBUG_KERNEL
1332 help
1333 A benchmark measuring the performance of the rbtree library.
1334 Also includes rbtree invariant checks.
1335
fff3fd8a
ML
1336config INTERVAL_TREE_TEST
1337 tristate "Interval tree test"
1338 depends on m && DEBUG_KERNEL
1339 help
1340 A benchmark measuring the performance of the interval tree library
1341
f212ec4b 1342config PROVIDE_OHCI1394_DMA_INIT
080de8c2 1343 bool "Remote debugging over FireWire early on boot"
f212ec4b
BK
1344 depends on PCI && X86
1345 help
1346 If you want to debug problems which hang or crash the kernel early
1347 on boot and the crashing machine has a FireWire port, you can use
1348 this feature to remotely access the memory of the crashed machine
1349 over FireWire. This employs remote DMA as part of the OHCI1394
1350 specification which is now the standard for FireWire controllers.
1351
1352 With remote DMA, you can monitor the printk buffer remotely using
1353 firescope and access all memory below 4GB using fireproxy from gdb.
1354 Even controlling a kernel debugger is possible using remote DMA.
1355
1356 Usage:
1357
1358 If ohci1394_dma=early is used as boot parameter, it will initialize
1359 all OHCI1394 controllers which are found in the PCI config space.
1360
1361 As all changes to the FireWire bus such as enabling and disabling
1362 devices cause a bus reset and thereby disable remote DMA for all
1363 devices, be sure to have the cable plugged and FireWire enabled on
1364 the debugging host before booting the debug target for debugging.
1365
1366 This code (~1k) is freed after boot. By then, the firewire stack
1367 in charge of the OHCI-1394 controllers should be used instead.
1368
1369 See Documentation/debugging-via-ohci1394.txt for more information.
9745512c 1370
080de8c2
SR
1371config FIREWIRE_OHCI_REMOTE_DMA
1372 bool "Remote debugging over FireWire with firewire-ohci"
1373 depends on FIREWIRE_OHCI
1374 help
1375 This option lets you use the FireWire bus for remote debugging
1376 with help of the firewire-ohci driver. It enables unfiltered
1377 remote DMA in firewire-ohci.
1378 See Documentation/debugging-via-ohci1394.txt for more information.
1379
1380 If unsure, say N.
1381
152de30b 1382config BUILD_DOCSRC
3794f3e8
RD
1383 bool "Build targets in Documentation/ tree"
1384 depends on HEADERS_CHECK
1385 help
1386 This option attempts to build objects from the source files in the
1387 kernel Documentation/ tree.
1388
1389 Say N if you are unsure.
1390
e9d376f0 1391config DYNAMIC_DEBUG
86151fdf 1392 bool "Enable dynamic printk() support"
346e15be
JB
1393 default n
1394 depends on PRINTK
86151fdf 1395 depends on DEBUG_FS
346e15be
JB
1396 help
1397
1398 Compiles debug level messages into the kernel, which would not
1399 otherwise be available at runtime. These messages can then be
86151fdf
JB
1400 enabled/disabled based on various levels of scope - per source file,
1401 function, module, format string, and line number. This mechanism
29e36c9f
JC
1402 implicitly compiles in all pr_debug() and dev_dbg() calls, which
1403 enlarges the kernel text size by about 2%.
1404
1405 If a source file is compiled with DEBUG flag set, any
1406 pr_debug() calls in it are enabled by default, but can be
1407 disabled at runtime as below. Note that DEBUG flag is
1408 turned on by many CONFIG_*DEBUG* options.
346e15be
JB
1409
1410 Usage:
1411
2b2f68b5 1412 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
86151fdf
JB
1413 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1414 filesystem must first be mounted before making use of this feature.
2b2f68b5 1415 We refer the control file as: <debugfs>/dynamic_debug/control. This
86151fdf
JB
1416 file contains a list of the debug statements that can be enabled. The
1417 format for each line of the file is:
346e15be 1418
86151fdf 1419 filename:lineno [module]function flags format
346e15be 1420
86151fdf
JB
1421 filename : source file of the debug statement
1422 lineno : line number of the debug statement
1423 module : module that contains the debug statement
1424 function : function that contains the debug statement
29e36c9f 1425 flags : '=p' means the line is turned 'on' for printing
86151fdf 1426 format : the format used for the debug statement
346e15be
JB
1427
1428 From a live system:
1429
2b2f68b5 1430 nullarbor:~ # cat <debugfs>/dynamic_debug/control
86151fdf 1431 # filename:lineno [module]function flags format
29e36c9f
JC
1432 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
1433 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
1434 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
346e15be 1435
86151fdf 1436 Example usage:
346e15be 1437
86151fdf
JB
1438 // enable the message at line 1603 of file svcsock.c
1439 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
2b2f68b5 1440 <debugfs>/dynamic_debug/control
346e15be 1441
86151fdf
JB
1442 // enable all the messages in file svcsock.c
1443 nullarbor:~ # echo -n 'file svcsock.c +p' >
2b2f68b5 1444 <debugfs>/dynamic_debug/control
346e15be 1445
86151fdf
JB
1446 // enable all the messages in the NFS server module
1447 nullarbor:~ # echo -n 'module nfsd +p' >
2b2f68b5 1448 <debugfs>/dynamic_debug/control
346e15be 1449
86151fdf
JB
1450 // enable all 12 messages in the function svc_process()
1451 nullarbor:~ # echo -n 'func svc_process +p' >
2b2f68b5 1452 <debugfs>/dynamic_debug/control
346e15be 1453
86151fdf
JB
1454 // disable all 12 messages in the function svc_process()
1455 nullarbor:~ # echo -n 'func svc_process -p' >
2b2f68b5 1456 <debugfs>/dynamic_debug/control
346e15be 1457
86151fdf 1458 See Documentation/dynamic-debug-howto.txt for additional information.
346e15be 1459
5ee00bd4
JR
1460config DMA_API_DEBUG
1461 bool "Enable debugging of DMA-API usage"
1462 depends on HAVE_DMA_API_DEBUG
1463 help
1464 Enable this option to debug the use of the DMA API by device drivers.
1465 With this option you will be able to detect common bugs in device
1466 drivers like double-freeing of DMA mappings or freeing mappings that
1467 were never allocated.
1468 This option causes a performance degredation. Use only if you want
1469 to debug device drivers. If unsure, say N.
346e15be 1470
86a89380
LB
1471config ATOMIC64_SELFTEST
1472 bool "Perform an atomic64_t self-test at boot"
1473 help
1474 Enable this option to test the atomic64_t functions at boot.
1475
1476 If unsure, say N.
1477
400fb7f6
DW
1478config ASYNC_RAID6_TEST
1479 tristate "Self test for hardware accelerated raid6 recovery"
1480 depends on ASYNC_RAID6_RECOV
1481 select ASYNC_MEMCPY
1482 ---help---
1483 This is a one-shot self test that permutes through the
1484 recovery of all the possible two disk failure scenarios for a
1485 N-disk array. Recovery is performed with the asynchronous
1486 raid6 recovery routines, and will optionally use an offload
1487 engine if one is available.
1488
1489 If unsure, say N.
1490
267c4025 1491source "samples/Kconfig"
dc7d5527
JW
1492
1493source "lib/Kconfig.kgdb"
0a4af3b0
PE
1494
1495source "lib/Kconfig.kmemcheck"
33ee3b2e 1496
16c7fa05
AS
1497config TEST_STRING_HELPERS
1498 tristate "Test functions located in the string_helpers module at runtime"
1499
33ee3b2e
AD
1500config TEST_KSTRTOX
1501 tristate "Test kstrto*() family of functions at runtime"