blob: db25707aa41bc021b8174391091178b85258d466 [file] [log] [blame]
Dave Hansen604ff0d2013-07-01 13:04:49 -07001menu "printk and dmesg options"
Linus Torvalds1da177e2005-04-16 15:20:36 -07002
3config PRINTK_TIME
4 bool "Show timing information on printks"
Randy Dunlapd3b8b6e2006-12-06 20:36:38 -08005 depends on PRINTK
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 help
Kay Sievers649e6ee2012-05-10 04:30:45 +02007 Selecting this option causes time stamps of the printk()
8 messages to be added to the output of the syslog() system
9 call and at the console.
10
11 The timestamp is always recorded internally, and exported
12 to /dev/kmsg. This flag just specifies if the timestamp should
13 be included, not that the timestamp is recorded.
14
15 The behavior is also controlled by the kernel command line
16 parameter printk.time=1. See Documentation/kernel-parameters.txt
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070018config DEFAULT_MESSAGE_LOGLEVEL
19 int "Default message log level (1-7)"
20 range 1 7
21 default "4"
22 help
23 Default log level for printk statements with no specified priority.
24
25 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
26 that are auditing their logs closely may want to set it to a lower
27 priority.
28
Dave Hansen604ff0d2013-07-01 13:04:49 -070029config BOOT_PRINTK_DELAY
30 bool "Delay each boot printk message by N milliseconds"
31 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
32 help
33 This build option allows you to read kernel boot messages
34 by inserting a short delay after each one. The delay is
35 specified in milliseconds on the kernel command line,
36 using "boot_delay=N".
37
38 It is likely that you would also need to use "lpj=M" to preset
39 the "loops per jiffie" value.
40 See a previous boot log for the "lpj" value to use for your
41 system, and then set "lpj=M" before setting "boot_delay=N".
42 NOTE: Using this option may adversely affect SMP systems.
43 I.e., processors other than the first one may not boot up.
44 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
45 what it believes to be lockup conditions.
46
47config DYNAMIC_DEBUG
48 bool "Enable dynamic printk() support"
49 default n
50 depends on PRINTK
51 depends on DEBUG_FS
52 help
53
54 Compiles debug level messages into the kernel, which would not
55 otherwise be available at runtime. These messages can then be
56 enabled/disabled based on various levels of scope - per source file,
57 function, module, format string, and line number. This mechanism
58 implicitly compiles in all pr_debug() and dev_dbg() calls, which
59 enlarges the kernel text size by about 2%.
60
61 If a source file is compiled with DEBUG flag set, any
62 pr_debug() calls in it are enabled by default, but can be
63 disabled at runtime as below. Note that DEBUG flag is
64 turned on by many CONFIG_*DEBUG* options.
65
66 Usage:
67
68 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
69 which is contained in the 'debugfs' filesystem. Thus, the debugfs
70 filesystem must first be mounted before making use of this feature.
71 We refer the control file as: <debugfs>/dynamic_debug/control. This
72 file contains a list of the debug statements that can be enabled. The
73 format for each line of the file is:
74
75 filename:lineno [module]function flags format
76
77 filename : source file of the debug statement
78 lineno : line number of the debug statement
79 module : module that contains the debug statement
80 function : function that contains the debug statement
81 flags : '=p' means the line is turned 'on' for printing
82 format : the format used for the debug statement
83
84 From a live system:
85
86 nullarbor:~ # cat <debugfs>/dynamic_debug/control
87 # filename:lineno [module]function flags format
88 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
89 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
90 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
91
92 Example usage:
93
94 // enable the message at line 1603 of file svcsock.c
95 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
96 <debugfs>/dynamic_debug/control
97
98 // enable all the messages in file svcsock.c
99 nullarbor:~ # echo -n 'file svcsock.c +p' >
100 <debugfs>/dynamic_debug/control
101
102 // enable all the messages in the NFS server module
103 nullarbor:~ # echo -n 'module nfsd +p' >
104 <debugfs>/dynamic_debug/control
105
106 // enable all 12 messages in the function svc_process()
107 nullarbor:~ # echo -n 'func svc_process +p' >
108 <debugfs>/dynamic_debug/control
109
110 // disable all 12 messages in the function svc_process()
111 nullarbor:~ # echo -n 'func svc_process -p' >
112 <debugfs>/dynamic_debug/control
113
114 See Documentation/dynamic-debug-howto.txt for additional information.
115
116endmenu # "printk and dmesg options"
117
Dave Hansen6dfc0662013-07-01 13:04:46 -0700118menu "Compile-time checks and compiler options"
119
120config DEBUG_INFO
121 bool "Compile the kernel with debug info"
122 depends on DEBUG_KERNEL
123 help
124 If you say Y here the resulting kernel image will include
125 debugging info resulting in a larger kernel image.
126 This adds debug symbols to the kernel and modules (gcc -g), and
127 is needed if you intend to use kernel crashdump or binary object
128 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
129 Say Y here only if you plan to debug the kernel.
130
131 If unsure, say N.
132
133config DEBUG_INFO_REDUCED
134 bool "Reduce debugging information"
135 depends on DEBUG_INFO
136 help
137 If you say Y here gcc is instructed to generate less debugging
138 information for structure types. This means that tools that
139 need full debugging information (like kgdb or systemtap) won't
140 be happy. But if you merely need debugging information to
141 resolve line numbers there is no loss. Advantage is that
142 build directory object sizes shrink dramatically over a full
143 DEBUG_INFO build and compile times are reduced too.
144 Only works with newer gcc versions.
145
Jeff Garzikde488442007-10-25 04:06:13 -0400146config ENABLE_WARN_DEPRECATED
147 bool "Enable __deprecated logic"
148 default y
149 help
150 Enable the __deprecated logic in the kernel build.
151 Disable this to suppress the "warning: 'foo' is deprecated
152 (declared at kernel/power/somefile.c:1234)" messages.
153
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700154config ENABLE_MUST_CHECK
155 bool "Enable __must_check logic"
156 default y
157 help
158 Enable the __must_check logic in the kernel build. Disable this to
159 suppress the "warning: ignoring return value of 'foo', declared with
160 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161
Andi Kleen35bb5b12008-02-22 15:15:03 +0100162config FRAME_WARN
163 int "Warn for stack frames larger than (needs gcc 4.4)"
164 range 0 8192
165 default 1024 if !64BIT
166 default 2048 if 64BIT
167 help
168 Tell gcc to warn at build time for stack frames larger than this.
169 Setting this too low will cause a lot of warnings.
170 Setting it to 0 disables the warning.
171 Requires gcc 4.4
172
Randy Dunlap99657c72009-09-18 12:49:22 -0700173config STRIP_ASM_SYMS
174 bool "Strip assembler-generated symbols during link"
175 default n
176 help
177 Strip internal assembler-generated symbols during a link (symbols
178 that look like '.Lxxx') so they don't pollute the output of
179 get_wchan() and suchlike.
180
Andi Kleen1873e872012-03-28 11:51:18 -0700181config READABLE_ASM
182 bool "Generate readable assembler code"
183 depends on DEBUG_KERNEL
184 help
185 Disable some compiler optimizations that tend to generate human unreadable
186 assembler output. This may make the kernel slightly slower, but it helps
187 to keep kernel developers who have to stare a lot at assembler listings
188 sane.
189
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700190config UNUSED_SYMBOLS
191 bool "Enable unused/obsolete exported symbols"
192 default y if X86
193 help
194 Unused but exported symbols make the kernel needlessly bigger. For
195 that reason most of these unused exports will soon be removed. This
196 option is provided temporarily to provide a transition period in case
197 some external kernel module needs one of these symbols anyway. If you
198 encounter such a case in your module, consider if you are actually
199 using the right API. (rationale: since nobody in the kernel is using
200 this in a module, there is a pretty good chance it's actually the
201 wrong interface to use). If you really need the symbol, please send a
202 mail to the linux kernel mailing list mentioning the symbol and why
203 you really need it, and what the merge plan to the mainline kernel for
204 your module is.
205
Don Mullisbf4735a2006-12-10 02:18:37 -0800206config DEBUG_FS
207 bool "Debug Filesystem"
Don Mullisbf4735a2006-12-10 02:18:37 -0800208 help
209 debugfs is a virtual file system that kernel developers use to put
210 debugging files into. Enable this option to be able to read and
211 write to these files.
212
Robert P. J. Dayff543332008-05-20 00:06:00 +0200213 For detailed documentation on the debugfs API, see
214 Documentation/DocBook/filesystems.
215
Don Mullisbf4735a2006-12-10 02:18:37 -0800216 If unsure, say N.
217
218config HEADERS_CHECK
219 bool "Run 'make headers_check' when building vmlinux"
220 depends on !UML
221 help
222 This option will extract the user-visible kernel headers whenever
223 building the kernel, and will run basic sanity checks on them to
224 ensure that exported files do not attempt to include files which
225 were not exported, etc.
226
227 If you're making modifications to header files which are
228 relevant for userspace, say 'Y', and check the headers
229 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
230 your build tree), to make sure they're suitable.
231
Sam Ravnborg91341d42008-01-21 21:31:44 +0100232config DEBUG_SECTION_MISMATCH
233 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100234 help
235 The section mismatch analysis checks if there are illegal
236 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000237 During linktime or runtime, some sections are dropped;
238 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100239 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000240 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400241 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100242 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000243 The section mismatch analysis is always performed after a full
244 kernel build, and enabling this option causes the following
245 additional steps to occur:
246 - Add the option -fno-inline-functions-called-once to gcc commands.
247 When inlining a function annotated with __init in a non-init
248 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100249 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000250 This option tells gcc to inline less (but it does result in
251 a larger kernel).
252 - Run the section mismatch analysis for each module/built-in.o file.
253 When we run the section mismatch analysis on vmlinux.o, we
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100254 lose valueble information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100255 introduced.
256 Running the analysis for each module/built-in.o file
Michael Wittene809ab02011-04-17 04:08:48 +0000257 tells where the mismatch happens much closer to the
258 source. The drawback is that the same mismatch is
259 reported at least twice.
260 - Enable verbose reporting from modpost in order to help resolve
261 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100262
Dave Hansen6dfc0662013-07-01 13:04:46 -0700263#
264# Select this config option from the architecture Kconfig, if it
265# is preferred to always offer frame pointers as a config
266# option on the architecture (regardless of KERNEL_DEBUG):
267#
268config ARCH_WANT_FRAME_POINTERS
269 bool
270 help
271
272config FRAME_POINTER
273 bool "Compile the kernel with frame pointers"
274 depends on DEBUG_KERNEL && \
275 (CRIS || M68K || FRV || UML || \
276 AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || \
277 ARCH_WANT_FRAME_POINTERS
278 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
279 help
280 If you say Y here the resulting kernel image will be slightly
281 larger and slower, but it gives very useful debugging information
282 in case of kernel bugs. (precise oopses/stacktraces/warnings)
283
284config DEBUG_FORCE_WEAK_PER_CPU
285 bool "Force weak per-cpu definitions"
286 depends on DEBUG_KERNEL
287 help
288 s390 and alpha require percpu variables in modules to be
289 defined weak to work around addressing range issue which
290 puts the following two restrictions on percpu variable
291 definitions.
292
293 1. percpu symbols must be unique whether static or not
294 2. percpu variables can't be defined inside a function
295
296 To ensure that generic code follows the above rules, this
297 option forces all percpu variables to be defined as weak.
298
299endmenu # "Compiler options"
300
301config MAGIC_SYSRQ
302 bool "Magic SysRq key"
303 depends on !UML
304 help
305 If you say Y here, you will have some control over the system even
306 if the system crashes for example during kernel debugging (e.g., you
307 will be able to flush the buffer cache to disk, reboot the system
308 immediately or dump some status information). This is accomplished
309 by pressing various keys while holding SysRq (Alt+PrintScreen). It
310 also works on a serial console (on PC hardware at least), if you
311 send a BREAK and then within 5 seconds a command keypress. The
312 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
313 unless you really know what this hack does.
314
Ben Hutchings8eaede42013-10-07 01:05:46 +0100315config MAGIC_SYSRQ_DEFAULT_ENABLE
316 hex "Enable magic SysRq key functions by default"
317 depends on MAGIC_SYSRQ
318 default 0x1
319 help
320 Specifies which SysRq key functions are enabled by default.
321 This may be set to 1 or 0 to enable or disable them all, or
322 to a bitmask as described in Documentation/sysrq.txt.
323
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800324config DEBUG_KERNEL
325 bool "Kernel debugging"
326 help
327 Say Y here if you are developing drivers or trying to debug and
328 identify kernel problems.
329
Dave Hansen0610c8a2013-07-01 13:04:43 -0700330menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800331
Dave Hansen0610c8a2013-07-01 13:04:43 -0700332source mm/Kconfig.debug
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800333
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700334config DEBUG_OBJECTS
335 bool "Debug object operations"
336 depends on DEBUG_KERNEL
337 help
338 If you say Y here, additional code will be inserted into the
339 kernel to track the life time of various objects and validate
340 the operations on those objects.
341
342config DEBUG_OBJECTS_SELFTEST
343 bool "Debug objects selftest"
344 depends on DEBUG_OBJECTS
345 help
346 This enables the selftest of the object debug code.
347
348config DEBUG_OBJECTS_FREE
349 bool "Debug objects in freed memory"
350 depends on DEBUG_OBJECTS
351 help
352 This enables checks whether a k/v free operation frees an area
353 which contains an object which has not been deactivated
354 properly. This can make kmalloc/kfree-intensive workloads
355 much slower.
356
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700357config DEBUG_OBJECTS_TIMERS
358 bool "Debug timer objects"
359 depends on DEBUG_OBJECTS
360 help
361 If you say Y here, additional code will be inserted into the
362 timer routines to track the life time of timer objects and
363 validate the timer operations.
364
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900365config DEBUG_OBJECTS_WORK
366 bool "Debug work objects"
367 depends on DEBUG_OBJECTS
368 help
369 If you say Y here, additional code will be inserted into the
370 work queue routines to track the life time of work objects and
371 validate the work operations.
372
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400373config DEBUG_OBJECTS_RCU_HEAD
374 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800375 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400376 help
377 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
378
Tejun Heoe2852ae2010-10-26 14:23:05 -0700379config DEBUG_OBJECTS_PERCPU_COUNTER
380 bool "Debug percpu counter objects"
381 depends on DEBUG_OBJECTS
382 help
383 If you say Y here, additional code will be inserted into the
384 percpu counter routines to track the life time of percpu counter
385 objects and validate the percpu counter operations.
386
Ingo Molnar3ae70202008-11-26 10:02:00 +0100387config DEBUG_OBJECTS_ENABLE_DEFAULT
388 int "debug_objects bootup default value (0-1)"
389 range 0 1
390 default "1"
391 depends on DEBUG_OBJECTS
392 help
393 Debug objects boot parameter default value
394
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800396 bool "Debug slab memory allocations"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200397 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 help
399 Say Y here to have the kernel do limited verification on memory
400 allocation as well as poisoning memory on free to catch use of freed
401 memory. This can make kmalloc/kfree-intensive workloads much slower.
402
Al Viro871751e2006-03-25 03:06:39 -0800403config DEBUG_SLAB_LEAK
404 bool "Memory leak debugging"
405 depends on DEBUG_SLAB
406
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700407config SLUB_DEBUG_ON
408 bool "SLUB debugging on by default"
Vegard Nossum7d46d9e2008-04-04 00:51:41 +0200409 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700410 default n
411 help
412 Boot with debugging on by default. SLUB boots by default with
413 the runtime debug capabilities switched off. Enabling this is
414 equivalent to specifying the "slub_debug" parameter on boot.
415 There is no support for more fine grained debug control like
416 possible with slub_debug=xxx. SLUB debugging may be switched
417 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
418 "slub_debug=-".
419
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800420config SLUB_STATS
421 default n
422 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500423 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800424 help
425 SLUB statistics are useful to debug SLUBs allocation behavior in
426 order find ways to optimize the allocator. This should never be
427 enabled for production use since keeping statistics slows down
428 the allocator by a few percentage points. The slabinfo command
429 supports the determination of the most active slabs to figure
430 out which slabs are relevant to a particular load.
431 Try running: slabinfo -DA
432
Catalin Marinasb69ec422012-10-08 16:28:11 -0700433config HAVE_DEBUG_KMEMLEAK
434 bool
435
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100436config DEBUG_KMEMLEAK
437 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800438 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100439 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100440 select STACKTRACE if STACKTRACE_SUPPORT
441 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800442 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100443 help
444 Say Y here if you want to enable the memory leak
445 detector. The memory allocation/freeing is traced in a way
446 similar to the Boehm's conservative garbage collector, the
447 difference being that the orphan objects are not freed but
448 only shown in /sys/kernel/debug/kmemleak. Enabling this
449 feature will introduce an overhead to memory
450 allocations. See Documentation/kmemleak.txt for more
451 details.
452
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100453 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
454 of finding leaks due to the slab objects poisoning.
455
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100456 In order to access the kmemleak file, debugfs needs to be
457 mounted (usually at /sys/kernel/debug).
458
Catalin Marinasa9d90582009-06-25 10:16:11 +0100459config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
460 int "Maximum kmemleak early log entries"
461 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200462 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100463 default 400
464 help
465 Kmemleak must track all the memory allocations to avoid
466 reporting false positives. Since memory may be allocated or
467 freed before kmemleak is initialised, an early log buffer is
468 used to store these actions. If kmemleak reports "early log
469 buffer exceeded", please increase this value.
470
Catalin Marinas0822ee42009-06-11 13:24:14 +0100471config DEBUG_KMEMLEAK_TEST
472 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700473 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100474 help
Daniel Baluta97182692011-04-04 15:06:44 -0700475 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100476
477 If unsure, say N.
478
Jason Baronab0155a2010-07-19 11:54:17 +0100479config DEBUG_KMEMLEAK_DEFAULT_OFF
480 bool "Default kmemleak to off"
481 depends on DEBUG_KMEMLEAK
482 help
483 Say Y here to disable kmemleak by default. It can then be enabled
484 on the command line via kmemleak=on.
485
Dave Hansen0610c8a2013-07-01 13:04:43 -0700486config DEBUG_STACK_USAGE
487 bool "Stack utilization instrumentation"
488 depends on DEBUG_KERNEL && !IA64 && !PARISC && !METAG
489 help
490 Enables the display of the minimum amount of free stack which each
491 task has ever had available in the sysrq-T and sysrq-P debug output.
492
493 This option will slow down process creation somewhat.
494
495config DEBUG_VM
496 bool "Debug VM"
497 depends on DEBUG_KERNEL
498 help
499 Enable this to turn on extended checks in the virtual-memory system
500 that may impact performance.
501
502 If unsure, say N.
503
504config DEBUG_VM_RB
505 bool "Debug VM red-black trees"
506 depends on DEBUG_VM
507 help
508 Enable this to turn on more extended checks in the virtual-memory
509 system that may impact performance.
510
511 If unsure, say N.
512
513config DEBUG_VIRTUAL
514 bool "Debug VM translations"
515 depends on DEBUG_KERNEL && X86
516 help
517 Enable some costly sanity checks in virtual to page code. This can
518 catch mistakes with virt_to_page() and friends.
519
520 If unsure, say N.
521
522config DEBUG_NOMMU_REGIONS
523 bool "Debug the global anon/private NOMMU mapping region tree"
524 depends on DEBUG_KERNEL && !MMU
525 help
526 This option causes the global tree of anonymous and private mapping
527 regions to be regularly checked for invalid topology.
528
529config DEBUG_MEMORY_INIT
530 bool "Debug memory initialisation" if EXPERT
531 default !EXPERT
532 help
533 Enable this for additional checks during memory initialisation.
534 The sanity checks verify aspects of the VM such as the memory model
535 and other information provided by the architecture. Verbose
536 information will be printed at KERN_DEBUG loglevel depending
537 on the mminit_loglevel= command-line option.
538
539 If unsure, say Y
540
541config MEMORY_NOTIFIER_ERROR_INJECT
542 tristate "Memory hotplug notifier error injection module"
543 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
544 help
545 This option provides the ability to inject artificial errors to
546 memory hotplug notifier chain callbacks. It is controlled through
547 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
548
549 If the notifier call chain should be failed with some events
550 notified, write the error code to "actions/<notifier event>/error".
551
552 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
553
554 # cd /sys/kernel/debug/notifier-error-inject/memory
555 # echo -12 > actions/MEM_GOING_OFFLINE/error
556 # echo offline > /sys/devices/system/memory/memoryXXX/state
557 bash: echo: write error: Cannot allocate memory
558
559 To compile this code as a module, choose M here: the module will
560 be called memory-notifier-error-inject.
561
562 If unsure, say N.
563
564config DEBUG_PER_CPU_MAPS
565 bool "Debug access to per_cpu maps"
566 depends on DEBUG_KERNEL
567 depends on SMP
568 help
569 Say Y to verify that the per_cpu map being accessed has
570 been set up. This adds a fair amount of code to kernel memory
571 and decreases performance.
572
573 Say N if unsure.
574
575config DEBUG_HIGHMEM
576 bool "Highmem debugging"
577 depends on DEBUG_KERNEL && HIGHMEM
578 help
579 This options enables addition error checking for high memory systems.
580 Disable for production systems.
581
582config HAVE_DEBUG_STACKOVERFLOW
583 bool
584
585config DEBUG_STACKOVERFLOW
586 bool "Check for stack overflows"
587 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
588 ---help---
589 Say Y here if you want to check for overflows of kernel, IRQ
590 and exception stacks (if your archicture uses them). This
591 option will show detailed messages if free stack space drops
592 below a certain limit.
593
594 These kinds of bugs usually occur when call-chains in the
595 kernel get too deep, especially when interrupts are
596 involved.
597
598 Use this in cases where you see apparently random memory
599 corruption, especially if it appears in 'struct thread_info'
600
601 If in doubt, say "N".
602
603source "lib/Kconfig.kmemcheck"
604
605endmenu # "Memory Debugging"
606
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607config DEBUG_SHIRQ
608 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200609 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 help
611 Enable this to generate a spurious interrupt as soon as a shared
612 interrupt handler is registered, and just before one is deregistered.
613 Drivers ought to be able to handle interrupts coming in at those
614 points; some don't and need to be caught.
615
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700616menu "Debug Lockups and Hangs"
617
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618config LOCKUP_DETECTOR
619 bool "Detect Hard and Soft Lockups"
620 depends on DEBUG_KERNEL && !S390
621 help
622 Say Y here to enable the kernel to act as a watchdog to detect
623 hard and soft lockups.
624
625 Softlockups are bugs that cause the kernel to loop in kernel
626 mode for more than 20 seconds, without giving other tasks a
627 chance to run. The current stack trace is displayed upon
628 detection and the system will stay locked up.
629
630 Hardlockups are bugs that cause the CPU to loop in kernel mode
631 for more than 10 seconds, without letting other interrupts have a
632 chance to run. The current stack trace is displayed upon detection
633 and the system will stay locked up.
634
635 The overhead should be minimal. A periodic hrtimer runs to
636 generate interrupts and kick the watchdog task every 4 seconds.
637 An NMI is generated every 10 seconds or so to check for hardlockups.
638
639 The frequency of hrtimer and NMI events and the soft and hard lockup
640 thresholds can be controlled through the sysctl watchdog_thresh.
641
642config HARDLOCKUP_DETECTOR
643 def_bool y
644 depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG
645 depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI
646
647config BOOTPARAM_HARDLOCKUP_PANIC
648 bool "Panic (Reboot) On Hard Lockups"
649 depends on HARDLOCKUP_DETECTOR
650 help
651 Say Y here to enable the kernel to panic on "hard lockups",
652 which are bugs that cause the kernel to loop in kernel
653 mode with interrupts disabled for more than 10 seconds (configurable
654 using the watchdog_thresh sysctl).
655
656 Say N if unsure.
657
658config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
659 int
660 depends on HARDLOCKUP_DETECTOR
661 range 0 1
662 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
663 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
664
665config BOOTPARAM_SOFTLOCKUP_PANIC
666 bool "Panic (Reboot) On Soft Lockups"
667 depends on LOCKUP_DETECTOR
668 help
669 Say Y here to enable the kernel to panic on "soft lockups",
670 which are bugs that cause the kernel to loop in kernel
671 mode for more than 20 seconds (configurable using the watchdog_thresh
672 sysctl), without giving other tasks a chance to run.
673
674 The panic can be used in combination with panic_timeout,
675 to cause the system to reboot automatically after a
676 lockup has been detected. This feature is useful for
677 high-availability systems that have uptime guarantees and
678 where a lockup must be resolved ASAP.
679
Ingo Molnar8637c092006-07-03 00:24:38 -0700680 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
682config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
683 int
684 depends on LOCKUP_DETECTOR
685 range 0 1
686 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
687 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700688
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689config DETECT_HUNG_TASK
690 bool "Detect Hung Tasks"
691 depends on DEBUG_KERNEL
692 default LOCKUP_DETECTOR
693 help
694 Say Y here to enable the kernel to detect "hung tasks",
695 which are bugs that cause the task to be stuck in
696 uninterruptible "D" state indefinitiley.
697
698 When a hung task is detected, the kernel will print the
699 current stack trace (which you should report), but the
700 task will stay in uninterruptible state. If lockdep is
701 enabled then all held locks will also be reported. This
702 feature has negligible overhead.
703
704config DEFAULT_HUNG_TASK_TIMEOUT
705 int "Default timeout for hung task detection (in seconds)"
706 depends on DETECT_HUNG_TASK
707 default 120
708 help
709 This option controls the default timeout (in seconds) used
710 to determine when a task has become non-responsive and should
711 be considered hung.
712
713 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
714 sysctl or by writing a value to
715 /proc/sys/kernel/hung_task_timeout_secs.
716
Ingo Molnar408894e2006-01-09 15:59:20 -0800717 A timeout of 0 disables the check. The default is two minutes.
718 Keeping the default should be fine in most cases.
719
720config BOOTPARAM_HUNG_TASK_PANIC
721 bool "Panic (Reboot) On Hung Tasks"
722 depends on DETECT_HUNG_TASK
Tim Chencca57c52006-04-18 22:21:47 -0700723 help
Ingo Molnar408894e2006-01-09 15:59:20 -0800724 Say Y here to enable the kernel to panic on "hung tasks",
725 which are bugs that cause the kernel to leave a task stuck
726 in uninterruptible "D" state.
727
728 The panic can be used in combination with panic_timeout,
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700729 to cause the system to reboot automatically after a
730 hung task has been detected. This feature is useful for
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700731 high-availability systems that have uptime guarantees and
732 where a hung tasks must be resolved ASAP.
733
734 Say N if unsure.
735
736config BOOTPARAM_HUNG_TASK_PANIC_VALUE
737 int
738 depends on DETECT_HUNG_TASK
739 range 0 1
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100740 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 default 1 if BOOTPARAM_HUNG_TASK_PANIC
742
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700743endmenu # "Debug lockups and hangs"
744
745config PANIC_ON_OOPS
746 bool "Panic on Oops"
747 help
748 Say Y here to enable the kernel to panic when it oopses. This
749 has the same effect as setting oops=panic on the kernel command
750 line.
751
752 This feature is useful to ensure that the kernel does not do
753 anything erroneous after an oops which could result in data
754 corruption or other issues.
755
756 Say N if unsure.
757
758config PANIC_ON_OOPS_VALUE
759 int
760 range 0 1
761 default 0 if !PANIC_ON_OOPS
762 default 1 if PANIC_ON_OOPS
763
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764config SCHED_DEBUG
765 bool "Collect scheduler debugging info"
766 depends on DEBUG_KERNEL && PROC_FS
767 default y
768 help
769 If you say Y here, the /proc/sched_debug file will be provided
770 that can help debug the scheduler. The runtime overhead of this
771 option is minimal.
772
773config SCHEDSTATS
774 bool "Collect scheduler statistics"
775 depends on DEBUG_KERNEL && PROC_FS
776 help
777 If you say Y here, additional code will be inserted into the
778 scheduler and related routines to collect statistics about
779 scheduler behavior and provide them in /proc/schedstat. These
780 stats may be useful for both tuning and debugging the scheduler
781 If you aren't debugging the scheduler or trying to tune a specific
782 application, you can say N to avoid the very slight overhead
783 this adds.
784
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700785config TIMER_STATS
786 bool "Collect kernel timers statistics"
787 depends on DEBUG_KERNEL && PROC_FS
788 help
789 If you say Y here, additional code will be inserted into the
790 timer routines to collect statistics about kernel timers being
791 reprogrammed. The statistics can be read from /proc/timer_stats.
792 The statistics collection is started by writing 1 to /proc/timer_stats,
793 writing 0 stops it. This feature is useful to collect information
794 about timer usage patterns in kernel and userspace. This feature
795 is lightweight if enabled in the kernel config but not activated
796 (it defaults to deactivated on bootup and will only be activated
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700797 if some application like powertop activates it explicitly).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799config DEBUG_PREEMPT
800 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +0000801 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 default y
803 help
804 If you say Y here then the kernel will use a debug variant of the
805 commonly used smp_processor_id() function and will print warnings
806 if kernel code uses it in a preemption-unsafe way. Also, the kernel
807 will detect preemption count underflows.
808
Dave Hansen9eade162013-07-01 13:04:47 -0700809menu "Lock Debugging (spinlocks, mutexes, etc...)"
810
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811config DEBUG_RT_MUTEXES
812 bool "RT Mutex debugging, deadlock detection"
813 depends on DEBUG_KERNEL && RT_MUTEXES
814 help
815 This allows rt mutex semantics violations and rt mutex related
816 deadlocks (lockups) to be detected and reported automatically.
817
818config DEBUG_PI_LIST
819 bool
820 default y
821 depends on DEBUG_RT_MUTEXES
822
823config RT_MUTEX_TESTER
824 bool "Built-in scriptable tester for rt-mutexes"
825 depends on DEBUG_KERNEL && RT_MUTEXES
826 help
827 This option enables a rt-mutex tester.
828
829config DEBUG_SPINLOCK
830 bool "Spinlock and rw-lock debugging: basic checks"
831 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +0530832 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 help
834 Say Y here and build SMP to catch missing spinlock initialization
835 and certain other kinds of spinlock errors commonly made. This is
836 best used in conjunction with the NMI watchdog so that spinlock
837 deadlocks are also debuggable.
838
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700839config DEBUG_MUTEXES
840 bool "Mutex debugging: basic checks"
841 depends on DEBUG_KERNEL
842 help
843 This feature allows mutex semantics violations to be detected and
844 reported.
845
Daniel Vetter23010022013-06-20 13:31:17 +0200846config DEBUG_WW_MUTEX_SLOWPATH
847 bool "Wait/wound mutex debugging: Slowpath testing"
848 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
849 select DEBUG_LOCK_ALLOC
850 select DEBUG_SPINLOCK
851 select DEBUG_MUTEXES
852 help
853 This feature enables slowpath testing for w/w mutex users by
854 injecting additional -EDEADLK wound/backoff cases. Together with
855 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
856 will test all possible w/w mutex interface abuse with the
857 exception of simply not acquiring all the required locks.
858
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700859config DEBUG_LOCK_ALLOC
860 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700861 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700862 select DEBUG_SPINLOCK
863 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700864 select LOCKDEP
865 help
866 This feature will check whether any held lock (spinlock, rwlock,
867 mutex or rwsem) is incorrectly freed by the kernel, via any of the
868 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
869 vfree(), etc.), whether a live lock is incorrectly reinitialized via
870 spin_lock_init()/mutex_init()/etc., or whether there is any lock
871 held during task exit.
872
873config PROVE_LOCKING
874 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700875 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700876 select LOCKDEP
877 select DEBUG_SPINLOCK
878 select DEBUG_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700879 select DEBUG_LOCK_ALLOC
Steven Rostedt46b93b72010-08-31 16:35:20 -0400880 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700881 default n
882 help
883 This feature enables the kernel to prove that all locking
884 that occurs in the kernel runtime is mathematically
885 correct: that under no circumstance could an arbitrary (and
886 not yet triggered) combination of observed locking
887 sequences (on an arbitrary number of CPUs, running an
888 arbitrary number of tasks and interrupt contexts) cause a
889 deadlock.
890
891 In short, this feature enables the kernel to report locking
892 related deadlocks before they actually occur.
893
894 The proof does not depend on how hard and complex a
895 deadlock scenario would be to trigger: how many
896 participant CPUs, tasks and irq-contexts would be needed
897 for it to trigger. The proof also does not depend on
898 timing: if a race and a resulting deadlock is possible
899 theoretically (no matter how unlikely the race scenario
900 is), it will be proven so and will immediately be
901 reported by the kernel (once the event is observed that
902 makes the deadlock theoretically possible).
903
904 If a deadlock is impossible (i.e. the locking rules, as
905 observed by the kernel, are mathematically correct), the
906 kernel reports nothing.
907
908 NOTE: this feature can also be enabled for rwlocks, mutexes
909 and rwsems - in which case all dependencies between these
910 different locking variants are observed and mapped too, and
911 the proof of observed correctness is also maintained for an
912 arbitrary combination of these separate locking variants.
913
914 For more details, see Documentation/lockdep-design.txt.
915
916config LOCKDEP
917 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700918 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700919 select STACKTRACE
Vineet Guptacc80ae32013-08-27 13:52:51 +0530920 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700921 select KALLSYMS
922 select KALLSYMS_ALL
923
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700924config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -0700925 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700926 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
927 select LOCKDEP
928 select DEBUG_SPINLOCK
929 select DEBUG_MUTEXES
930 select DEBUG_LOCK_ALLOC
931 default n
932 help
933 This feature enables tracking lock contention points
934
Peter Zijlstraa560aa42007-10-07 00:24:33 -0700935 For more details, see Documentation/lockstat.txt
936
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100937 This also enables lock events required by "perf lock",
938 subcommand of perf.
939 If you want to use "perf lock", you also need to turn on
940 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900941
942 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +0100943 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +0900944
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700945config DEBUG_LOCKDEP
946 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -0700947 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -0700948 help
949 If you say Y here, the lock dependency engine will do
950 additional runtime checks to debug itself, at the price
951 of more runtime overhead.
952
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200953config DEBUG_ATOMIC_SLEEP
954 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +0200955 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 depends on DEBUG_KERNEL
957 help
958 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +0200959 noisy if they are called inside atomic sections: when a spinlock is
960 held, inside an rcu read side critical section, inside preempt disabled
961 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962
Ingo Molnarcae2ed92006-07-03 00:24:48 -0700963config DEBUG_LOCKING_API_SELFTESTS
964 bool "Locking API boot-time self-tests"
965 depends on DEBUG_KERNEL
966 help
967 Say Y here if you want the kernel to run a short self-test during
968 bootup. The self-test checks whether common types of locking bugs
969 are detected by debugging mechanisms or not. (if you disable
970 lock debugging then those bugs wont be detected of course.)
971 The following locking APIs are covered: spinlocks, rwlocks,
972 mutexes and rwsems.
973
Dave Hansen9eade162013-07-01 13:04:47 -0700974endmenu # lock debugging
975
976config TRACE_IRQFLAGS
977 bool
978 help
979 Enables hooks to interrupt enabling and disabling for
980 either tracing or lock debugging.
981
Ingo Molnar8637c092006-07-03 00:24:38 -0700982config STACKTRACE
983 bool
984 depends on STACKTRACE_SUPPORT
985
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986config DEBUG_KOBJECT
987 bool "kobject debugging"
988 depends on DEBUG_KERNEL
989 help
990 If you say Y here, some extra kobject debugging messages will be sent
991 to the syslog.
992
Russell Kingc817a672013-06-27 15:06:14 +0100993config DEBUG_KOBJECT_RELEASE
994 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -0700995 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +0100996 help
997 kobjects are reference counted objects. This means that their
998 last reference count put is not predictable, and the kobject can
999 live on past the point at which a driver decides to drop it's
1000 initial reference to the kobject gained on allocation. An
1001 example of this would be a struct device which has just been
1002 unregistered.
1003
1004 However, some buggy drivers assume that after such an operation,
1005 the memory backing the kobject can be immediately freed. This
1006 goes completely against the principles of a refcounted object.
1007
1008 If you say Y here, the kernel will delay the release of kobjects
1009 on the last reference count to improve the visibility of this
1010 kind of kobject release bug.
1011
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001012config HAVE_DEBUG_BUGVERBOSE
1013 bool
1014
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001016 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001017 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001018 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 help
1020 Say Y here to make BUG() panics output the file name and line number
1021 of the BUG call as well as the EIP and oops trace. This aids
1022 debugging but costs about 70-100K of memory.
1023
Dave Hansenad775f52008-02-15 14:38:01 -08001024config DEBUG_WRITECOUNT
1025 bool "Debug filesystem writers count"
1026 depends on DEBUG_KERNEL
1027 help
1028 Enable this to catch wrong use of the writers count in struct
1029 vfsmount. This will increase the size of each file struct by
1030 32 bits.
1031
1032 If unsure, say N.
1033
Dave Jones199a9af2006-09-29 01:59:00 -07001034config DEBUG_LIST
1035 bool "Debug linked list manipulation"
1036 depends on DEBUG_KERNEL
1037 help
1038 Enable this to turn on extended checks in the linked-list
1039 walking routines.
1040
1041 If unsure, say N.
1042
Jens Axboed6ec0842007-10-22 20:01:06 +02001043config DEBUG_SG
1044 bool "Debug SG table operations"
1045 depends on DEBUG_KERNEL
1046 help
1047 Enable this to turn on checks on scatter-gather tables. This can
1048 help find problems with drivers that do not properly initialize
1049 their sg tables.
1050
1051 If unsure, say N.
1052
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001053config DEBUG_NOTIFIERS
1054 bool "Debug notifier call chains"
1055 depends on DEBUG_KERNEL
1056 help
1057 Enable this to turn on sanity checking for notifier call chains.
1058 This is most useful for kernel developers to make sure that
1059 modules properly unregister themselves from notifier chains.
1060 This is a relatively cheap check but if you care about maximum
1061 performance, say N.
1062
David Howellse0e81732009-09-02 09:13:40 +01001063config DEBUG_CREDENTIALS
1064 bool "Debug credential management"
1065 depends on DEBUG_KERNEL
1066 help
1067 Enable this to turn on some debug checking for credential
1068 management. The additional code keeps track of the number of
1069 pointers from task_structs to any given cred struct, and checks to
1070 see that this number never exceeds the usage count of the cred
1071 struct.
1072
1073 Furthermore, if SELinux is enabled, this also checks that the
1074 security pointer in the cred struct is never seen to be invalid.
1075
1076 If unsure, say N.
1077
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001078menu "RCU Debugging"
1079
1080config PROVE_RCU
1081 bool "RCU debugging: prove RCU correctness"
1082 depends on PROVE_LOCKING
1083 default n
1084 help
1085 This feature enables lockdep extensions that check for correct
1086 use of RCU APIs. This is currently under development. Say Y
1087 if you want to debug RCU usage or help work on the PROVE_RCU
1088 feature.
1089
1090 Say N if you are unsure.
1091
1092config PROVE_RCU_REPEATEDLY
1093 bool "RCU debugging: don't disable PROVE_RCU on first splat"
1094 depends on PROVE_RCU
1095 default n
1096 help
1097 By itself, PROVE_RCU will disable checking upon issuing the
1098 first warning (or "splat"). This feature prevents such
1099 disabling, allowing multiple RCU-lockdep warnings to be printed
1100 on a single reboot.
1101
1102 Say Y to allow multiple RCU-lockdep warnings per boot.
1103
1104 Say N if you are unsure.
1105
1106config PROVE_RCU_DELAY
1107 bool "RCU debugging: preemptible RCU race provocation"
1108 depends on DEBUG_KERNEL && PREEMPT_RCU
1109 default n
1110 help
1111 There is a class of races that involve an unlikely preemption
1112 of __rcu_read_unlock() just after ->rcu_read_lock_nesting has
1113 been set to INT_MIN. This feature inserts a delay at that
1114 point to increase the probability of these races.
1115
1116 Say Y to increase probability of preemption of __rcu_read_unlock().
1117
1118 Say N if you are unsure.
1119
1120config SPARSE_RCU_POINTER
1121 bool "RCU debugging: sparse-based checks for pointer usage"
1122 default n
1123 help
1124 This feature enables the __rcu sparse annotation for
1125 RCU-protected pointers. This annotation will cause sparse
1126 to flag any non-RCU used of annotated pointers. This can be
1127 helpful when debugging RCU usage. Please note that this feature
1128 is not intended to enforce code cleanliness; it is instead merely
1129 a debugging aid.
1130
1131 Say Y to make sparse flag questionable use of RCU-protected pointers
1132
1133 Say N if you are unsure.
1134
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001135config RCU_TORTURE_TEST
1136 tristate "torture tests for RCU"
1137 depends on DEBUG_KERNEL
1138 default n
1139 help
1140 This option provides a kernel module that runs torture tests
1141 on the RCU infrastructure. The kernel module may be built
1142 after the fact on the running kernel to be tested, if desired.
1143
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001144 Say Y here if you want RCU torture tests to be built into
1145 the kernel.
Paul E. McKenneya241ec62005-10-30 15:03:12 -08001146 Say M if you want the RCU torture tests to build as a module.
1147 Say N if you are unsure.
Ankita Garg8bb31b92006-10-02 02:17:36 -07001148
Paul E. McKenney31a72bc2008-06-18 09:26:49 -07001149config RCU_TORTURE_TEST_RUNNABLE
1150 bool "torture tests for RCU runnable by default"
1151 depends on RCU_TORTURE_TEST = y
1152 default n
1153 help
1154 This option provides a way to build the RCU torture tests
1155 directly into the kernel without them starting up at boot
1156 time. You can use /proc/sys/kernel/rcutorture_runnable
1157 to manually override this setting. This /proc file is
1158 available only when the RCU torture tests have been built
1159 into the kernel.
1160
1161 Say Y here if you want the RCU torture tests to start during
1162 boot (you probably don't).
1163 Say N here if you want the RCU torture tests to start only
1164 after being manually enabled via /proc.
1165
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001166config RCU_CPU_STALL_TIMEOUT
1167 int "RCU CPU stall timeout in seconds"
Paul E. McKenney6bfc09e2012-10-19 12:49:17 -07001168 depends on RCU_STALL_COMMON
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001169 range 3 300
Paul E. McKenneyc8960542012-10-25 17:59:23 -07001170 default 21
Paul E. McKenneyb1637602010-06-02 16:21:38 -07001171 help
1172 If a given RCU grace period extends more than the specified
1173 number of seconds, a CPU stall warning is printed. If the
1174 RCU grace period persists, additional CPU stall warnings are
1175 printed at more widely spaced intervals.
1176
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001177config RCU_CPU_STALL_VERBOSE
1178 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
Paul E. McKenneya00e0d712011-02-08 17:14:39 -08001179 depends on TREE_PREEMPT_RCU
Paul E. McKenney55ec9362010-04-13 12:22:33 -07001180 default y
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001181 help
1182 This option causes RCU to printk detailed per-task information
1183 for any tasks that are stalling the current RCU grace period.
Paul E. McKenney64db4cf2008-12-18 21:55:32 +01001184
1185 Say N if you are unsure.
1186
Paul E. McKenney1ed509a2010-02-22 17:05:05 -08001187 Say Y if you want to enable such checks.
1188
Paul E. McKenneya858af22012-01-16 13:29:10 -08001189config RCU_CPU_STALL_INFO
1190 bool "Print additional diagnostics on RCU CPU stall"
1191 depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
1192 default n
1193 help
1194 For each stalled CPU that is aware of the current RCU grace
1195 period, print out additional per-CPU diagnostic information
1196 regarding scheduling-clock ticks, idle state, and,
1197 for RCU_FAST_NO_HZ kernels, idle-entry state.
1198
1199 Say N if you are unsure.
1200
1201 Say Y if you want to enable such diagnostics.
1202
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001203config RCU_TRACE
1204 bool "Enable tracing for RCU"
1205 depends on DEBUG_KERNEL
Paul E. McKenney52494532012-11-14 16:26:40 -08001206 select TRACE_CLOCK
Paul E. McKenney5c8806a2012-01-06 15:10:44 -08001207 help
1208 This option provides tracing in RCU which presents stats
1209 in debugfs for debugging RCU implementation.
1210
1211 Say Y here if you want to enable RCU tracing
1212 Say N if you are unsure.
1213
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001214endmenu # "RCU Debugging"
1215
Tejun Heo870d6652008-08-25 19:47:25 +09001216config DEBUG_BLOCK_EXT_DEVT
1217 bool "Force extended block device numbers and spread them"
1218 depends on DEBUG_KERNEL
1219 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001220 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001221 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001222 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1223 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1224 YOU ARE DOING. Distros, please enable this and fix whatever
1225 is broken.
1226
Tejun Heo870d6652008-08-25 19:47:25 +09001227 Conventionally, block device numbers are allocated from
1228 predetermined contiguous area. However, extended block area
1229 may introduce non-contiguous block device numbers. This
1230 option forces most block device numbers to be allocated from
1231 the extended space and spreads them to discover kernel or
1232 userland code paths which assume predetermined contiguous
1233 device number allocation.
1234
Tejun Heo55dc7db2008-09-01 13:44:35 +02001235 Note that turning on this debug option shuffles all the
1236 device numbers for all IDE and SCSI devices including libata
1237 ones, so root partition specified using device number
1238 directly (via rdev or root=MAJ:MIN) won't work anymore.
1239 Textual device names (root=/dev/sdXn) will continue to work.
1240
Tejun Heo870d6652008-08-25 19:47:25 +09001241 Say N if you are unsure.
1242
Akinobu Mita8d438282012-07-30 14:43:02 -07001243config NOTIFIER_ERROR_INJECTION
1244 tristate "Notifier error injection"
1245 depends on DEBUG_KERNEL
1246 select DEBUG_FS
1247 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001248 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001249 specified notifier chain callbacks. It is useful to test the error
1250 handling of notifier call chain failures.
1251
1252 Say N if unsure.
1253
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001254config CPU_NOTIFIER_ERROR_INJECT
1255 tristate "CPU notifier error injection module"
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001256 depends on HOTPLUG_CPU && NOTIFIER_ERROR_INJECTION
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001257 help
1258 This option provides a kernel module that can be used to test
Masanari Iidae41e85c2012-11-30 16:44:39 +09001259 the error handling of the cpu notifiers by injecting artificial
Akinobu Mitaf5a9f522012-07-30 14:43:03 -07001260 errors to CPU notifier chain callbacks. It is controlled through
1261 debugfs interface under /sys/kernel/debug/notifier-error-inject/cpu
1262
1263 If the notifier call chain should be failed with some events
1264 notified, write the error code to "actions/<notifier event>/error".
1265
1266 Example: Inject CPU offline error (-1 == -EPERM)
1267
1268 # cd /sys/kernel/debug/notifier-error-inject/cpu
1269 # echo -1 > actions/CPU_DOWN_PREPARE/error
1270 # echo 0 > /sys/devices/system/cpu/cpu1/online
1271 bash: echo: write error: Operation not permitted
Akinobu Mitac9d221f2010-05-26 14:43:36 -07001272
1273 To compile this code as a module, choose M here: the module will
1274 be called cpu-notifier-error-inject.
1275
1276 If unsure, say N.
1277
Akinobu Mita048b9c32012-07-30 14:43:07 -07001278config PM_NOTIFIER_ERROR_INJECT
1279 tristate "PM notifier error injection module"
1280 depends on PM && NOTIFIER_ERROR_INJECTION
1281 default m if PM_DEBUG
1282 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001283 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001284 PM notifier chain callbacks. It is controlled through debugfs
1285 interface /sys/kernel/debug/notifier-error-inject/pm
1286
1287 If the notifier call chain should be failed with some events
1288 notified, write the error code to "actions/<notifier event>/error".
1289
1290 Example: Inject PM suspend error (-12 = -ENOMEM)
1291
1292 # cd /sys/kernel/debug/notifier-error-inject/pm/
1293 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1294 # echo mem > /sys/power/state
1295 bash: echo: write error: Cannot allocate memory
1296
1297 To compile this code as a module, choose M here: the module will
1298 be called pm-notifier-error-inject.
1299
1300 If unsure, say N.
1301
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001302config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1303 tristate "OF reconfig notifier error injection module"
1304 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001305 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001306 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001307 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001308 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001309 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001310
1311 If the notifier call chain should be failed with some events
1312 notified, write the error code to "actions/<notifier event>/error".
1313
1314 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001315 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001316
1317 If unsure, say N.
1318
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001319config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001320 bool "Fault-injection framework"
1321 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001322 help
1323 Provide fault-injection framework.
1324 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001325
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001326config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001327 bool "Fault-injection capability for kmalloc"
1328 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001329 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001330 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001331 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001332
Akinobu Mita933e3122006-12-08 02:39:45 -08001333config FAIL_PAGE_ALLOC
1334 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001335 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001336 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001337 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001338
Akinobu Mitac17bb492006-12-08 02:39:46 -08001339config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001340 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001341 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001342 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001343 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001344
Jens Axboe581d4e22008-09-14 05:56:33 -07001345config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d014392010-07-21 16:05:53 +09001346 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001347 depends on FAULT_INJECTION && BLOCK
1348 help
1349 Provide fault-injection capability on end IO handling. This
1350 will make the block layer "forget" an interrupt as configured,
1351 thus exercising the error handling.
1352
1353 Only works with drivers that use the generic timeout handling,
1354 for others it wont do anything.
1355
Per Forlin1b676f72011-08-19 14:52:37 +02001356config FAIL_MMC_REQUEST
1357 bool "Fault-injection capability for MMC IO"
1358 select DEBUG_FS
1359 depends on FAULT_INJECTION && MMC
1360 help
1361 Provide fault-injection capability for MMC IO.
1362 This will make the mmc core return data errors. This is
1363 useful to test the error handling in the mmc block device
1364 and to test how the mmc host driver handles retries from
1365 the block device.
1366
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001367config FAULT_INJECTION_DEBUG_FS
1368 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001369 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001370 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001371 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001372
1373config FAULT_INJECTION_STACKTRACE_FILTER
1374 bool "stacktrace filter for fault-injection capabilities"
1375 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001376 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001377 select STACKTRACE
Vineet Guptacc80ae32013-08-27 13:52:51 +05301378 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
Akinobu Mita1df49002007-02-20 13:57:56 -08001379 help
1380 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001381
Arjan van de Ven97455122008-01-25 21:08:34 +01001382config LATENCYTOP
1383 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001384 depends on HAVE_LATENCYTOP_SUPPORT
1385 depends on DEBUG_KERNEL
1386 depends on STACKTRACE_SUPPORT
1387 depends on PROC_FS
Vineet Guptacc80ae32013-08-27 13:52:51 +05301388 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC
Arjan van de Ven97455122008-01-25 21:08:34 +01001389 select KALLSYMS
1390 select KALLSYMS_ALL
1391 select STACKTRACE
1392 select SCHEDSTATS
1393 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001394 help
1395 Enable this option if you want to use the LatencyTOP tool
1396 to find out which userspace is blocking on what kernel operations.
1397
Stephen Boyd446f24d2013-04-30 15:28:42 -07001398config ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1399 bool
1400
1401config DEBUG_STRICT_USER_COPY_CHECKS
1402 bool "Strict user copy size checks"
1403 depends on ARCH_HAS_DEBUG_STRICT_USER_COPY_CHECKS
1404 depends on DEBUG_KERNEL && !TRACE_BRANCH_PROFILING
1405 help
1406 Enabling this option turns a certain set of sanity checks for user
1407 copy operations into compile time failures.
1408
1409 The copy_from_user() etc checks are there to help test if there
1410 are sufficient security checks on the length argument of
1411 the copy operation, by having gcc prove that the argument is
1412 within bounds.
1413
1414 If unsure, say N.
1415
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001416source kernel/trace/Kconfig
1417
Dave Hansen881c5142013-07-01 13:04:44 -07001418menu "Runtime Testing"
1419
1420config LKDTM
1421 tristate "Linux Kernel Dump Test Tool Module"
1422 depends on DEBUG_FS
1423 depends on BLOCK
1424 default n
1425 help
1426 This module enables testing of the different dumping mechanisms by
1427 inducing system failures at predefined crash points.
1428 If you don't need it: say N
1429 Choose M here to compile this code as a module. The module will be
1430 called lkdtm.
1431
1432 Documentation on how to use the module can be found in
1433 Documentation/fault-injection/provoke-crashes.txt
1434
1435config TEST_LIST_SORT
1436 bool "Linked list sorting test"
1437 depends on DEBUG_KERNEL
1438 help
1439 Enable this to turn on 'list_sort()' function test. This test is
1440 executed only once during system boot, so affects only boot time.
1441
1442 If unsure, say N.
1443
1444config KPROBES_SANITY_TEST
1445 bool "Kprobes sanity tests"
1446 depends on DEBUG_KERNEL
1447 depends on KPROBES
1448 default n
1449 help
1450 This option provides for testing basic kprobes functionality on
1451 boot. A sample kprobe, jprobe and kretprobe are inserted and
1452 verified for functionality.
1453
1454 Say N if you are unsure.
1455
1456config BACKTRACE_SELF_TEST
1457 tristate "Self test for the backtrace code"
1458 depends on DEBUG_KERNEL
1459 default n
1460 help
1461 This option provides a kernel module that can be used to test
1462 the kernel stack backtrace code. This option is not useful
1463 for distributions or general kernels, but only for kernel
1464 developers working on architecture code.
1465
1466 Note that if you want to also test saved backtraces, you will
1467 have to enable STACKTRACE as well.
1468
1469 Say N if you are unsure.
1470
Michel Lespinasse910a7422012-10-08 16:30:39 -07001471config RBTREE_TEST
1472 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001473 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001474 help
1475 A benchmark measuring the performance of the rbtree library.
1476 Also includes rbtree invariant checks.
1477
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001478config INTERVAL_TREE_TEST
1479 tristate "Interval tree test"
1480 depends on m && DEBUG_KERNEL
1481 help
1482 A benchmark measuring the performance of the interval tree library
1483
Greg Thelen623fd802013-11-12 15:08:34 -08001484config PERCPU_TEST
1485 tristate "Per cpu operations test"
1486 depends on m && DEBUG_KERNEL
1487 help
1488 Enable this option to build test module which validates per-cpu
1489 operations.
1490
1491 If unsure, say N.
1492
Dave Hansen881c5142013-07-01 13:04:44 -07001493config ATOMIC64_SELFTEST
1494 bool "Perform an atomic64_t self-test at boot"
1495 help
1496 Enable this option to test the atomic64_t functions at boot.
1497
1498 If unsure, say N.
1499
1500config ASYNC_RAID6_TEST
1501 tristate "Self test for hardware accelerated raid6 recovery"
1502 depends on ASYNC_RAID6_RECOV
1503 select ASYNC_MEMCPY
1504 ---help---
1505 This is a one-shot self test that permutes through the
1506 recovery of all the possible two disk failure scenarios for a
1507 N-disk array. Recovery is performed with the asynchronous
1508 raid6 recovery routines, and will optionally use an offload
1509 engine if one is available.
1510
1511 If unsure, say N.
1512
1513config TEST_STRING_HELPERS
1514 tristate "Test functions located in the string_helpers module at runtime"
1515
1516config TEST_KSTRTOX
1517 tristate "Test kstrto*() family of functions at runtime"
1518
1519endmenu # runtime tests
1520
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001521config PROVIDE_OHCI1394_DMA_INIT
Stefan Richter080de8c2008-02-28 20:54:43 +01001522 bool "Remote debugging over FireWire early on boot"
Bernhard Kaindlf212ec42008-01-30 13:34:11 +01001523 depends on PCI && X86
1524 help
1525 If you want to debug problems which hang or crash the kernel early
1526 on boot and the crashing machine has a FireWire port, you can use
1527 this feature to remotely access the memory of the crashed machine
1528 over FireWire. This employs remote DMA as part of the OHCI1394
1529 specification which is now the standard for FireWire controllers.
1530
1531 With remote DMA, you can monitor the printk buffer remotely using
1532 firescope and access all memory below 4GB using fireproxy from gdb.
1533 Even controlling a kernel debugger is possible using remote DMA.
1534
1535 Usage:
1536
1537 If ohci1394_dma=early is used as boot parameter, it will initialize
1538 all OHCI1394 controllers which are found in the PCI config space.
1539
1540 As all changes to the FireWire bus such as enabling and disabling
1541 devices cause a bus reset and thereby disable remote DMA for all
1542 devices, be sure to have the cable plugged and FireWire enabled on
1543 the debugging host before booting the debug target for debugging.
1544
1545 This code (~1k) is freed after boot. By then, the firewire stack
1546 in charge of the OHCI-1394 controllers should be used instead.
1547
1548 See Documentation/debugging-via-ohci1394.txt for more information.
Arjan van de Ven97455122008-01-25 21:08:34 +01001549
Stefan Richter080de8c2008-02-28 20:54:43 +01001550config FIREWIRE_OHCI_REMOTE_DMA
1551 bool "Remote debugging over FireWire with firewire-ohci"
1552 depends on FIREWIRE_OHCI
1553 help
1554 This option lets you use the FireWire bus for remote debugging
1555 with help of the firewire-ohci driver. It enables unfiltered
1556 remote DMA in firewire-ohci.
1557 See Documentation/debugging-via-ohci1394.txt for more information.
1558
1559 If unsure, say N.
1560
Randy Dunlap152de302009-02-20 15:38:47 -08001561config BUILD_DOCSRC
Randy Dunlap3794f3e2008-08-12 15:09:06 -07001562 bool "Build targets in Documentation/ tree"
1563 depends on HEADERS_CHECK
1564 help
1565 This option attempts to build objects from the source files in the
1566 kernel Documentation/ tree.
1567
1568 Say N if you are unsure.
1569
Joerg Roedel5ee00bd2009-01-09 12:14:24 +01001570config DMA_API_DEBUG
1571 bool "Enable debugging of DMA-API usage"
1572 depends on HAVE_DMA_API_DEBUG
1573 help
1574 Enable this option to debug the use of the DMA API by device drivers.
1575 With this option you will be able to detect common bugs in device
1576 drivers like double-freeing of DMA mappings or freeing mappings that
1577 were never allocated.
1578 This option causes a performance degredation. Use only if you want
1579 to debug device drivers. If unsure, say N.
Jason Baron346e15b2008-08-12 16:46:19 -04001580
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001581source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001582
1583source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001584