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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
Mauro Carvalho Chehab8c27cef2016-10-18 10:12:27 -020016 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
Linus Torvalds1da177e2005-04-16 15:20:36 -070017
Olof Johanssona8cfdc62016-12-12 16:45:56 -080018config CONSOLE_LOGLEVEL_DEFAULT
19 int "Default console loglevel (1-15)"
20 range 1 15
21 default "7"
22 help
23 Default loglevel to determine what will be printed on the console.
24
25 Setting a default here is equivalent to passing in loglevel=<x> in
26 the kernel bootargs. loglevel=<x> continues to override whatever
27 value is specified here as well.
28
Borislav Petkov50f4d9b2016-12-19 16:23:15 -080029 Note: This does not affect the log level of un-prefixed printk()
Olof Johanssona8cfdc62016-12-12 16:45:56 -080030 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
31 option.
32
Alex Elder42a9dc02014-08-06 16:09:01 -070033config MESSAGE_LOGLEVEL_DEFAULT
Mandeep Singh Baines5af5bcb2011-03-22 16:34:23 -070034 int "Default message log level (1-7)"
35 range 1 7
36 default "4"
37 help
38 Default log level for printk statements with no specified priority.
39
40 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
41 that are auditing their logs closely may want to set it to a lower
42 priority.
43
Olof Johanssona8cfdc62016-12-12 16:45:56 -080044 Note: This does not affect what message level gets printed on the console
45 by default. To change that, use loglevel=<x> in the kernel bootargs,
46 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
47
Dave Hansen604ff0d2013-07-01 13:04:49 -070048config BOOT_PRINTK_DELAY
49 bool "Delay each boot printk message by N milliseconds"
50 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
51 help
52 This build option allows you to read kernel boot messages
53 by inserting a short delay after each one. The delay is
54 specified in milliseconds on the kernel command line,
55 using "boot_delay=N".
56
57 It is likely that you would also need to use "lpj=M" to preset
58 the "loops per jiffie" value.
59 See a previous boot log for the "lpj" value to use for your
60 system, and then set "lpj=M" before setting "boot_delay=N".
61 NOTE: Using this option may adversely affect SMP systems.
62 I.e., processors other than the first one may not boot up.
63 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
64 what it believes to be lockup conditions.
65
66config DYNAMIC_DEBUG
67 bool "Enable dynamic printk() support"
68 default n
69 depends on PRINTK
70 depends on DEBUG_FS
71 help
72
73 Compiles debug level messages into the kernel, which would not
74 otherwise be available at runtime. These messages can then be
75 enabled/disabled based on various levels of scope - per source file,
76 function, module, format string, and line number. This mechanism
77 implicitly compiles in all pr_debug() and dev_dbg() calls, which
78 enlarges the kernel text size by about 2%.
79
80 If a source file is compiled with DEBUG flag set, any
81 pr_debug() calls in it are enabled by default, but can be
82 disabled at runtime as below. Note that DEBUG flag is
83 turned on by many CONFIG_*DEBUG* options.
84
85 Usage:
86
87 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
88 which is contained in the 'debugfs' filesystem. Thus, the debugfs
89 filesystem must first be mounted before making use of this feature.
90 We refer the control file as: <debugfs>/dynamic_debug/control. This
91 file contains a list of the debug statements that can be enabled. The
92 format for each line of the file is:
93
94 filename:lineno [module]function flags format
95
96 filename : source file of the debug statement
97 lineno : line number of the debug statement
98 module : module that contains the debug statement
99 function : function that contains the debug statement
100 flags : '=p' means the line is turned 'on' for printing
101 format : the format used for the debug statement
102
103 From a live system:
104
105 nullarbor:~ # cat <debugfs>/dynamic_debug/control
106 # filename:lineno [module]function flags format
107 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
108 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
109 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
110
111 Example usage:
112
113 // enable the message at line 1603 of file svcsock.c
114 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
115 <debugfs>/dynamic_debug/control
116
117 // enable all the messages in file svcsock.c
118 nullarbor:~ # echo -n 'file svcsock.c +p' >
119 <debugfs>/dynamic_debug/control
120
121 // enable all the messages in the NFS server module
122 nullarbor:~ # echo -n 'module nfsd +p' >
123 <debugfs>/dynamic_debug/control
124
125 // enable all 12 messages in the function svc_process()
126 nullarbor:~ # echo -n 'func svc_process +p' >
127 <debugfs>/dynamic_debug/control
128
129 // disable all 12 messages in the function svc_process()
130 nullarbor:~ # echo -n 'func svc_process -p' >
131 <debugfs>/dynamic_debug/control
132
Hans Holmbergf8998c22017-03-16 09:37:32 +0100133 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
134 information.
Dave Hansen604ff0d2013-07-01 13:04:49 -0700135
136endmenu # "printk and dmesg options"
137
Dave Hansen6dfc0662013-07-01 13:04:46 -0700138menu "Compile-time checks and compiler options"
139
140config DEBUG_INFO
141 bool "Compile the kernel with debug info"
Linus Torvalds12b13832014-02-04 12:20:01 -0800142 depends on DEBUG_KERNEL && !COMPILE_TEST
Dave Hansen6dfc0662013-07-01 13:04:46 -0700143 help
144 If you say Y here the resulting kernel image will include
145 debugging info resulting in a larger kernel image.
146 This adds debug symbols to the kernel and modules (gcc -g), and
147 is needed if you intend to use kernel crashdump or binary object
148 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
149 Say Y here only if you plan to debug the kernel.
150
151 If unsure, say N.
152
153config DEBUG_INFO_REDUCED
154 bool "Reduce debugging information"
155 depends on DEBUG_INFO
156 help
157 If you say Y here gcc is instructed to generate less debugging
158 information for structure types. This means that tools that
159 need full debugging information (like kgdb or systemtap) won't
160 be happy. But if you merely need debugging information to
161 resolve line numbers there is no loss. Advantage is that
162 build directory object sizes shrink dramatically over a full
163 DEBUG_INFO build and compile times are reduced too.
164 Only works with newer gcc versions.
165
Andi Kleen866ced92014-07-30 20:50:18 +0200166config DEBUG_INFO_SPLIT
167 bool "Produce split debuginfo in .dwo files"
Sudip Mukherjeeda0510c2017-01-10 16:57:45 -0800168 depends on DEBUG_INFO && !FRV
Andi Kleen866ced92014-07-30 20:50:18 +0200169 help
170 Generate debug info into separate .dwo files. This significantly
171 reduces the build directory size for builds with DEBUG_INFO,
172 because it stores the information only once on disk in .dwo
173 files instead of multiple times in object files and executables.
174 In addition the debug information is also compressed.
175
176 Requires recent gcc (4.7+) and recent gdb/binutils.
177 Any tool that packages or reads debug information would need
178 to know about the .dwo files and include them.
179 Incompatible with older versions of ccache.
180
Andi Kleenbfaf2dd2014-07-30 20:50:19 +0200181config DEBUG_INFO_DWARF4
182 bool "Generate dwarf4 debuginfo"
183 depends on DEBUG_INFO
184 help
185 Generate dwarf4 debug info. This requires recent versions
186 of gcc and gdb. It makes the debug information larger.
187 But it significantly improves the success of resolving
188 variables in gdb on optimized code.
189
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800190config GDB_SCRIPTS
191 bool "Provide GDB scripts for kernel debugging"
192 depends on DEBUG_INFO
193 help
194 This creates the required links to GDB helper scripts in the
195 build directory. If you load vmlinux into gdb, the helper
196 scripts will be automatically imported by gdb as well, and
197 additional functions are available to analyze a Linux kernel
Andreas Platschek700199b02016-12-14 15:05:40 -0800198 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
199 for further details.
Jan Kiszka3ee7b3f2015-02-17 13:46:36 -0800200
Jeff Garzikde488442007-10-25 04:06:13 -0400201config ENABLE_WARN_DEPRECATED
202 bool "Enable __deprecated logic"
203 default y
204 help
205 Enable the __deprecated logic in the kernel build.
206 Disable this to suppress the "warning: 'foo' is deprecated
207 (declared at kernel/power/somefile.c:1234)" messages.
208
Andrew Mortoncebc04b2006-08-14 22:43:18 -0700209config ENABLE_MUST_CHECK
210 bool "Enable __must_check logic"
211 default y
212 help
213 Enable the __must_check logic in the kernel build. Disable this to
214 suppress the "warning: ignoring return value of 'foo', declared with
215 attribute warn_unused_result" messages.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216
Andi Kleen35bb5b12008-02-22 15:15:03 +0100217config FRAME_WARN
218 int "Warn for stack frames larger than (needs gcc 4.4)"
219 range 0 8192
Arnd Bergmann062cd342018-02-06 15:41:41 -0800220 default 3072 if KASAN_EXTRA
Kees Cook0e07f662016-10-27 17:46:41 -0700221 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
Helge Deller432654d2017-09-11 21:41:43 +0200222 default 1280 if (!64BIT && PARISC)
223 default 1024 if (!64BIT && !PARISC)
Andi Kleen35bb5b12008-02-22 15:15:03 +0100224 default 2048 if 64BIT
225 help
226 Tell gcc to warn at build time for stack frames larger than this.
227 Setting this too low will cause a lot of warnings.
228 Setting it to 0 disables the warning.
229 Requires gcc 4.4
230
Randy Dunlap99657c72009-09-18 12:49:22 -0700231config STRIP_ASM_SYMS
232 bool "Strip assembler-generated symbols during link"
233 default n
234 help
235 Strip internal assembler-generated symbols during a link (symbols
236 that look like '.Lxxx') so they don't pollute the output of
237 get_wchan() and suchlike.
238
Andi Kleen1873e872012-03-28 11:51:18 -0700239config READABLE_ASM
240 bool "Generate readable assembler code"
241 depends on DEBUG_KERNEL
242 help
243 Disable some compiler optimizations that tend to generate human unreadable
244 assembler output. This may make the kernel slightly slower, but it helps
245 to keep kernel developers who have to stare a lot at assembler listings
246 sane.
247
Arjan van de Venf71d20e2006-06-28 04:26:45 -0700248config UNUSED_SYMBOLS
249 bool "Enable unused/obsolete exported symbols"
250 default y if X86
251 help
252 Unused but exported symbols make the kernel needlessly bigger. For
253 that reason most of these unused exports will soon be removed. This
254 option is provided temporarily to provide a transition period in case
255 some external kernel module needs one of these symbols anyway. If you
256 encounter such a case in your module, consider if you are actually
257 using the right API. (rationale: since nobody in the kernel is using
258 this in a module, there is a pretty good chance it's actually the
259 wrong interface to use). If you really need the symbol, please send a
260 mail to the linux kernel mailing list mentioning the symbol and why
261 you really need it, and what the merge plan to the mainline kernel for
262 your module is.
263
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800264config PAGE_OWNER
265 bool "Track page owner"
266 depends on DEBUG_KERNEL && STACKTRACE_SUPPORT
267 select DEBUG_FS
268 select STACKTRACE
Joonsoo Kimf2ca0b52016-07-26 15:23:55 -0700269 select STACKDEPOT
Joonsoo Kim48c96a32014-12-12 16:56:01 -0800270 select PAGE_EXTENSION
271 help
272 This keeps track of what call chain is the owner of a page, may
273 help to find bare alloc_page(s) leaks. Even if you include this
274 feature on your build, it is disabled in default. You should pass
275 "page_owner=on" to boot parameter in order to enable it. Eats
276 a fair amount of memory if enabled. See tools/vm/page_owner_sort.c
277 for user-space helper.
278
279 If unsure, say N.
280
Don Mullisbf4735a2006-12-10 02:18:37 -0800281config DEBUG_FS
282 bool "Debug Filesystem"
Nicolai Stange9fd4dce2016-03-22 14:11:13 +0100283 select SRCU
Don Mullisbf4735a2006-12-10 02:18:37 -0800284 help
285 debugfs is a virtual file system that kernel developers use to put
286 debugging files into. Enable this option to be able to read and
287 write to these files.
288
Robert P. J. Dayff543332008-05-20 00:06:00 +0200289 For detailed documentation on the debugfs API, see
Mauro Carvalho Chehabe1b4fc72017-05-14 12:04:55 -0300290 Documentation/filesystems/.
Robert P. J. Dayff543332008-05-20 00:06:00 +0200291
Don Mullisbf4735a2006-12-10 02:18:37 -0800292 If unsure, say N.
293
294config HEADERS_CHECK
295 bool "Run 'make headers_check' when building vmlinux"
296 depends on !UML
297 help
298 This option will extract the user-visible kernel headers whenever
299 building the kernel, and will run basic sanity checks on them to
300 ensure that exported files do not attempt to include files which
301 were not exported, etc.
302
303 If you're making modifications to header files which are
304 relevant for userspace, say 'Y', and check the headers
305 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
306 your build tree), to make sure they're suitable.
307
Sam Ravnborg91341d42008-01-21 21:31:44 +0100308config DEBUG_SECTION_MISMATCH
309 bool "Enable full Section mismatch analysis"
Sam Ravnborg91341d42008-01-21 21:31:44 +0100310 help
311 The section mismatch analysis checks if there are illegal
312 references from one section to another section.
Michael Wittene809ab02011-04-17 04:08:48 +0000313 During linktime or runtime, some sections are dropped;
314 any use of code/data previously in these sections would
Sam Ravnborg91341d42008-01-21 21:31:44 +0100315 most likely result in an oops.
Michael Wittene809ab02011-04-17 04:08:48 +0000316 In the code, functions and variables are annotated with
Paul Gortmaker0db06282013-06-19 14:53:51 -0400317 __init,, etc. (see the full list in include/linux/init.h),
Geert Uytterhoevend6fbfa42008-01-30 11:13:23 +0100318 which results in the code/data being placed in specific sections.
Michael Wittene809ab02011-04-17 04:08:48 +0000319 The section mismatch analysis is always performed after a full
320 kernel build, and enabling this option causes the following
321 additional steps to occur:
322 - Add the option -fno-inline-functions-called-once to gcc commands.
323 When inlining a function annotated with __init in a non-init
324 function, we would lose the section information and thus
Sam Ravnborg91341d42008-01-21 21:31:44 +0100325 the analysis would not catch the illegal reference.
Michael Wittene809ab02011-04-17 04:08:48 +0000326 This option tells gcc to inline less (but it does result in
327 a larger kernel).
328 - Run the section mismatch analysis for each module/built-in.o file.
329 When we run the section mismatch analysis on vmlinux.o, we
Uwe Kleine-König67797b92016-09-09 10:04:58 +0200330 lose valuable information about where the mismatch was
Sam Ravnborg91341d42008-01-21 21:31:44 +0100331 introduced.
332 Running the analysis for each module/built-in.o file
Michael Wittene809ab02011-04-17 04:08:48 +0000333 tells where the mismatch happens much closer to the
334 source. The drawback is that the same mismatch is
335 reported at least twice.
336 - Enable verbose reporting from modpost in order to help resolve
337 the section mismatches that are reported.
Sam Ravnborg91341d42008-01-21 21:31:44 +0100338
Nicolas Boichat47490ec2015-10-06 09:44:42 +1030339config SECTION_MISMATCH_WARN_ONLY
340 bool "Make section mismatch errors non-fatal"
341 default y
342 help
343 If you say N here, the build process will fail if there are any
344 section mismatch, instead of just throwing warnings.
345
346 If unsure, say Y.
347
Dave Hansen6dfc0662013-07-01 13:04:46 -0700348#
349# Select this config option from the architecture Kconfig, if it
350# is preferred to always offer frame pointers as a config
351# option on the architecture (regardless of KERNEL_DEBUG):
352#
353config ARCH_WANT_FRAME_POINTERS
354 bool
355 help
356
357config FRAME_POINTER
358 bool "Compile the kernel with frame pointers"
359 depends on DEBUG_KERNEL && \
360 (CRIS || M68K || FRV || UML || \
Hans-Christian Noren Egtvedt695c1202017-04-09 10:45:27 +0200361 SUPERH || BLACKFIN || MN10300 || METAG) || \
Dave Hansen6dfc0662013-07-01 13:04:46 -0700362 ARCH_WANT_FRAME_POINTERS
363 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
364 help
365 If you say Y here the resulting kernel image will be slightly
366 larger and slower, but it gives very useful debugging information
367 in case of kernel bugs. (precise oopses/stacktraces/warnings)
368
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600369config STACK_VALIDATION
370 bool "Compile-time stack metadata validation"
371 depends on HAVE_STACK_VALIDATION
372 default n
373 help
374 Add compile-time checks to validate stack metadata, including frame
375 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
376 that runtime stack traces are more reliable.
377
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500378 This is also a prerequisite for generation of ORC unwind data, which
Josh Poimboeuf8af220c2017-10-13 15:02:00 -0500379 is needed for CONFIG_UNWINDER_ORC.
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500380
Josh Poimboeufb9ab5eb2016-02-28 22:22:42 -0600381 For more information, see
382 tools/objtool/Documentation/stack-validation.txt.
383
Dave Hansen6dfc0662013-07-01 13:04:46 -0700384config DEBUG_FORCE_WEAK_PER_CPU
385 bool "Force weak per-cpu definitions"
386 depends on DEBUG_KERNEL
387 help
388 s390 and alpha require percpu variables in modules to be
389 defined weak to work around addressing range issue which
390 puts the following two restrictions on percpu variable
391 definitions.
392
393 1. percpu symbols must be unique whether static or not
394 2. percpu variables can't be defined inside a function
395
396 To ensure that generic code follows the above rules, this
397 option forces all percpu variables to be defined as weak.
398
399endmenu # "Compiler options"
400
401config MAGIC_SYSRQ
402 bool "Magic SysRq key"
403 depends on !UML
404 help
405 If you say Y here, you will have some control over the system even
406 if the system crashes for example during kernel debugging (e.g., you
407 will be able to flush the buffer cache to disk, reboot the system
408 immediately or dump some status information). This is accomplished
409 by pressing various keys while holding SysRq (Alt+PrintScreen). It
410 also works on a serial console (on PC hardware at least), if you
411 send a BREAK and then within 5 seconds a command keypress. The
Hans Holmbergf8998c22017-03-16 09:37:32 +0100412 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
413 Don't say Y unless you really know what this hack does.
Dave Hansen6dfc0662013-07-01 13:04:46 -0700414
Ben Hutchings8eaede42013-10-07 01:05:46 +0100415config MAGIC_SYSRQ_DEFAULT_ENABLE
416 hex "Enable magic SysRq key functions by default"
417 depends on MAGIC_SYSRQ
418 default 0x1
419 help
420 Specifies which SysRq key functions are enabled by default.
421 This may be set to 1 or 0 to enable or disable them all, or
Hans Holmbergf8998c22017-03-16 09:37:32 +0100422 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
Ben Hutchings8eaede42013-10-07 01:05:46 +0100423
Felix Fietkau732dbf32016-12-22 08:31:34 +0100424config MAGIC_SYSRQ_SERIAL
425 bool "Enable magic SysRq key over serial"
426 depends on MAGIC_SYSRQ
427 default y
428 help
429 Many embedded boards have a disconnected TTL level serial which can
430 generate some garbage that can lead to spurious false sysrq detects.
431 This option allows you to decide whether you want to enable the
432 magic SysRq key.
433
Adrian Bunkf346f4b2006-01-09 20:54:51 -0800434config DEBUG_KERNEL
435 bool "Kernel debugging"
436 help
437 Say Y here if you are developing drivers or trying to debug and
438 identify kernel problems.
439
Dave Hansen0610c8a2013-07-01 13:04:43 -0700440menu "Memory Debugging"
David Woodhousea304e1b2007-02-12 00:52:00 -0800441
Dave Hansen0610c8a2013-07-01 13:04:43 -0700442source mm/Kconfig.debug
Ingo Molnar82f67cd2007-02-16 01:28:13 -0800443
Thomas Gleixner3ac7fe52008-04-30 00:55:01 -0700444config DEBUG_OBJECTS
445 bool "Debug object operations"
446 depends on DEBUG_KERNEL
447 help
448 If you say Y here, additional code will be inserted into the
449 kernel to track the life time of various objects and validate
450 the operations on those objects.
451
452config DEBUG_OBJECTS_SELFTEST
453 bool "Debug objects selftest"
454 depends on DEBUG_OBJECTS
455 help
456 This enables the selftest of the object debug code.
457
458config DEBUG_OBJECTS_FREE
459 bool "Debug objects in freed memory"
460 depends on DEBUG_OBJECTS
461 help
462 This enables checks whether a k/v free operation frees an area
463 which contains an object which has not been deactivated
464 properly. This can make kmalloc/kfree-intensive workloads
465 much slower.
466
Thomas Gleixnerc6f3a972008-04-30 00:55:03 -0700467config DEBUG_OBJECTS_TIMERS
468 bool "Debug timer objects"
469 depends on DEBUG_OBJECTS
470 help
471 If you say Y here, additional code will be inserted into the
472 timer routines to track the life time of timer objects and
473 validate the timer operations.
474
Thomas Gleixnerdc186ad2009-11-16 01:09:48 +0900475config DEBUG_OBJECTS_WORK
476 bool "Debug work objects"
477 depends on DEBUG_OBJECTS
478 help
479 If you say Y here, additional code will be inserted into the
480 work queue routines to track the life time of work objects and
481 validate the work operations.
482
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400483config DEBUG_OBJECTS_RCU_HEAD
484 bool "Debug RCU callbacks objects"
Mathieu Desnoyersfc2ecf72011-02-23 09:42:14 -0800485 depends on DEBUG_OBJECTS
Mathieu Desnoyers551d55a2010-04-17 08:48:42 -0400486 help
487 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
488
Tejun Heoe2852ae2010-10-26 14:23:05 -0700489config DEBUG_OBJECTS_PERCPU_COUNTER
490 bool "Debug percpu counter objects"
491 depends on DEBUG_OBJECTS
492 help
493 If you say Y here, additional code will be inserted into the
494 percpu counter routines to track the life time of percpu counter
495 objects and validate the percpu counter operations.
496
Ingo Molnar3ae70202008-11-26 10:02:00 +0100497config DEBUG_OBJECTS_ENABLE_DEFAULT
498 int "debug_objects bootup default value (0-1)"
499 range 0 1
500 default "1"
501 depends on DEBUG_OBJECTS
502 help
503 Debug objects boot parameter default value
504
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505config DEBUG_SLAB
Andrew Morton4a2f0ac2006-03-25 03:07:22 -0800506 bool "Debug slab memory allocations"
Levin, Alexander (Sasha Levin)f369f142017-11-15 17:36:02 -0800507 depends on DEBUG_KERNEL && SLAB
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 help
509 Say Y here to have the kernel do limited verification on memory
510 allocation as well as poisoning memory on free to catch use of freed
511 memory. This can make kmalloc/kfree-intensive workloads much slower.
512
Al Viro871751e2006-03-25 03:06:39 -0800513config DEBUG_SLAB_LEAK
514 bool "Memory leak debugging"
515 depends on DEBUG_SLAB
516
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700517config SLUB_DEBUG_ON
518 bool "SLUB debugging on by default"
Levin, Alexander (Sasha Levin)f369f142017-11-15 17:36:02 -0800519 depends on SLUB && SLUB_DEBUG
Christoph Lameterf0630ff2007-07-15 23:38:14 -0700520 default n
521 help
522 Boot with debugging on by default. SLUB boots by default with
523 the runtime debug capabilities switched off. Enabling this is
524 equivalent to specifying the "slub_debug" parameter on boot.
525 There is no support for more fine grained debug control like
526 possible with slub_debug=xxx. SLUB debugging may be switched
527 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
528 "slub_debug=-".
529
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800530config SLUB_STATS
531 default n
532 bool "Enable SLUB performance statistics"
Christoph Lameterab4d5ed2010-10-05 13:57:26 -0500533 depends on SLUB && SYSFS
Christoph Lameter8ff12cf2008-02-07 17:47:41 -0800534 help
535 SLUB statistics are useful to debug SLUBs allocation behavior in
536 order find ways to optimize the allocator. This should never be
537 enabled for production use since keeping statistics slows down
538 the allocator by a few percentage points. The slabinfo command
539 supports the determination of the most active slabs to figure
540 out which slabs are relevant to a particular load.
541 Try running: slabinfo -DA
542
Catalin Marinasb69ec422012-10-08 16:28:11 -0700543config HAVE_DEBUG_KMEMLEAK
544 bool
545
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100546config DEBUG_KMEMLEAK
547 bool "Kernel memory leak detector"
Kees Cook525c1f92013-01-16 18:54:16 -0800548 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
Catalin Marinas79e0d9b2011-04-27 17:06:19 +0100549 select DEBUG_FS
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100550 select STACKTRACE if STACKTRACE_SUPPORT
551 select KALLSYMS
Randy Dunlapb60e26a2009-11-06 15:33:45 -0800552 select CRC32
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100553 help
554 Say Y here if you want to enable the memory leak
555 detector. The memory allocation/freeing is traced in a way
556 similar to the Boehm's conservative garbage collector, the
557 difference being that the orphan objects are not freed but
558 only shown in /sys/kernel/debug/kmemleak. Enabling this
559 feature will introduce an overhead to memory
Andreas Platschek700199b02016-12-14 15:05:40 -0800560 allocations. See Documentation/dev-tools/kmemleak.rst for more
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100561 details.
562
Catalin Marinasbf96d1e2009-06-23 14:40:27 +0100563 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
564 of finding leaks due to the slab objects poisoning.
565
Catalin Marinas3bba00d2009-06-11 13:24:13 +0100566 In order to access the kmemleak file, debugfs needs to be
567 mounted (usually at /sys/kernel/debug).
568
Catalin Marinasa9d90582009-06-25 10:16:11 +0100569config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
570 int "Maximum kmemleak early log entries"
571 depends on DEBUG_KMEMLEAK
Heiko Carstensdfcc3e62009-10-06 10:33:57 +0200572 range 200 40000
Catalin Marinasa9d90582009-06-25 10:16:11 +0100573 default 400
574 help
575 Kmemleak must track all the memory allocations to avoid
576 reporting false positives. Since memory may be allocated or
577 freed before kmemleak is initialised, an early log buffer is
578 used to store these actions. If kmemleak reports "early log
579 buffer exceeded", please increase this value.
580
Catalin Marinas0822ee42009-06-11 13:24:14 +0100581config DEBUG_KMEMLEAK_TEST
582 tristate "Simple test for the kernel memory leak detector"
Daniel Baluta97182692011-04-04 15:06:44 -0700583 depends on DEBUG_KMEMLEAK && m
Catalin Marinas0822ee42009-06-11 13:24:14 +0100584 help
Daniel Baluta97182692011-04-04 15:06:44 -0700585 This option enables a module that explicitly leaks memory.
Catalin Marinas0822ee42009-06-11 13:24:14 +0100586
587 If unsure, say N.
588
Jason Baronab0155a2010-07-19 11:54:17 +0100589config DEBUG_KMEMLEAK_DEFAULT_OFF
590 bool "Default kmemleak to off"
591 depends on DEBUG_KMEMLEAK
592 help
593 Say Y here to disable kmemleak by default. It can then be enabled
594 on the command line via kmemleak=on.
595
Dave Hansen0610c8a2013-07-01 13:04:43 -0700596config DEBUG_STACK_USAGE
597 bool "Stack utilization instrumentation"
Helge Deller6c31da32016-03-19 17:54:10 +0100598 depends on DEBUG_KERNEL && !IA64
Dave Hansen0610c8a2013-07-01 13:04:43 -0700599 help
600 Enables the display of the minimum amount of free stack which each
601 task has ever had available in the sysrq-T and sysrq-P debug output.
602
603 This option will slow down process creation somewhat.
604
605config DEBUG_VM
606 bool "Debug VM"
607 depends on DEBUG_KERNEL
608 help
609 Enable this to turn on extended checks in the virtual-memory system
610 that may impact performance.
611
612 If unsure, say N.
613
Davidlohr Bueso4f115142014-06-04 16:06:46 -0700614config DEBUG_VM_VMACACHE
615 bool "Debug VMA caching"
616 depends on DEBUG_VM
617 help
618 Enable this to turn on VMA caching debug information. Doing so
619 can cause significant overhead, so only enable it in non-production
620 environments.
621
622 If unsure, say N.
623
Dave Hansen0610c8a2013-07-01 13:04:43 -0700624config DEBUG_VM_RB
625 bool "Debug VM red-black trees"
626 depends on DEBUG_VM
627 help
Davidlohr Buesoa663dad2014-04-18 15:07:22 -0700628 Enable VM red-black tree debugging information and extra validations.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700629
630 If unsure, say N.
631
Kirill A. Shutemov95ad9752016-01-15 16:51:21 -0800632config DEBUG_VM_PGFLAGS
633 bool "Debug page-flags operations"
634 depends on DEBUG_VM
635 help
636 Enables extra validation on page flags operations.
637
638 If unsure, say N.
639
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800640config ARCH_HAS_DEBUG_VIRTUAL
641 bool
642
Dave Hansen0610c8a2013-07-01 13:04:43 -0700643config DEBUG_VIRTUAL
644 bool "Debug VM translations"
Laura Abbottfa5b6ec2017-01-10 13:35:40 -0800645 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
Dave Hansen0610c8a2013-07-01 13:04:43 -0700646 help
647 Enable some costly sanity checks in virtual to page code. This can
648 catch mistakes with virt_to_page() and friends.
649
650 If unsure, say N.
651
652config DEBUG_NOMMU_REGIONS
653 bool "Debug the global anon/private NOMMU mapping region tree"
654 depends on DEBUG_KERNEL && !MMU
655 help
656 This option causes the global tree of anonymous and private mapping
657 regions to be regularly checked for invalid topology.
658
659config DEBUG_MEMORY_INIT
660 bool "Debug memory initialisation" if EXPERT
661 default !EXPERT
662 help
663 Enable this for additional checks during memory initialisation.
664 The sanity checks verify aspects of the VM such as the memory model
665 and other information provided by the architecture. Verbose
666 information will be printed at KERN_DEBUG loglevel depending
667 on the mminit_loglevel= command-line option.
668
669 If unsure, say Y
670
671config MEMORY_NOTIFIER_ERROR_INJECT
672 tristate "Memory hotplug notifier error injection module"
673 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
674 help
675 This option provides the ability to inject artificial errors to
676 memory hotplug notifier chain callbacks. It is controlled through
677 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
678
679 If the notifier call chain should be failed with some events
680 notified, write the error code to "actions/<notifier event>/error".
681
682 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
683
684 # cd /sys/kernel/debug/notifier-error-inject/memory
685 # echo -12 > actions/MEM_GOING_OFFLINE/error
686 # echo offline > /sys/devices/system/memory/memoryXXX/state
687 bash: echo: write error: Cannot allocate memory
688
689 To compile this code as a module, choose M here: the module will
690 be called memory-notifier-error-inject.
691
692 If unsure, say N.
693
694config DEBUG_PER_CPU_MAPS
695 bool "Debug access to per_cpu maps"
696 depends on DEBUG_KERNEL
697 depends on SMP
698 help
699 Say Y to verify that the per_cpu map being accessed has
700 been set up. This adds a fair amount of code to kernel memory
701 and decreases performance.
702
703 Say N if unsure.
704
705config DEBUG_HIGHMEM
706 bool "Highmem debugging"
707 depends on DEBUG_KERNEL && HIGHMEM
708 help
Geert Uytterhoevenb1357c92014-04-14 18:55:50 +0200709 This option enables additional error checking for high memory
710 systems. Disable for production systems.
Dave Hansen0610c8a2013-07-01 13:04:43 -0700711
712config HAVE_DEBUG_STACKOVERFLOW
713 bool
714
715config DEBUG_STACKOVERFLOW
716 bool "Check for stack overflows"
717 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
718 ---help---
719 Say Y here if you want to check for overflows of kernel, IRQ
Borislav Petkovedb0ec02015-01-25 19:50:34 +0100720 and exception stacks (if your architecture uses them). This
Dave Hansen0610c8a2013-07-01 13:04:43 -0700721 option will show detailed messages if free stack space drops
722 below a certain limit.
723
724 These kinds of bugs usually occur when call-chains in the
725 kernel get too deep, especially when interrupts are
726 involved.
727
728 Use this in cases where you see apparently random memory
729 corruption, especially if it appears in 'struct thread_info'
730
731 If in doubt, say "N".
732
Andrey Ryabinin0b24bec2015-02-13 14:39:17 -0800733source "lib/Kconfig.kasan"
734
Dave Hansen0610c8a2013-07-01 13:04:43 -0700735endmenu # "Memory Debugging"
736
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700737config ARCH_HAS_KCOV
738 bool
739 help
740 KCOV does not have any arch-specific code, but currently it is enabled
741 only for x86_64. KCOV requires testing on other archs, and most likely
742 disabling of instrumentation for some early boot code.
743
744config KCOV
745 bool "Code coverage for fuzzing"
746 depends on ARCH_HAS_KCOV
747 select DEBUG_FS
Kees Cooka519167e2016-06-11 09:09:28 -0700748 select GCC_PLUGINS if !COMPILE_TEST
749 select GCC_PLUGIN_SANCOV if !COMPILE_TEST
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700750 help
751 KCOV exposes kernel code coverage information in a form suitable
752 for coverage-guided fuzzing (randomized testing).
753
754 If RANDOMIZE_BASE is enabled, PC values will not be stable across
755 different machines and across reboots. If you need stable PC values,
756 disable RANDOMIZE_BASE.
757
Andreas Platschek700199b02016-12-14 15:05:40 -0800758 For more details, see Documentation/dev-tools/kcov.rst.
Dmitry Vyukov5c9a8752016-03-22 14:27:30 -0700759
Vegard Nossuma4691de2016-08-02 14:07:30 -0700760config KCOV_INSTRUMENT_ALL
761 bool "Instrument all code by default"
762 depends on KCOV
763 default y if KCOV
764 help
765 If you are doing generic system call fuzzing (like e.g. syzkaller),
766 then you will want to instrument the whole kernel and you should
767 say y here. If you are doing more targeted fuzzing (like e.g.
768 filesystem fuzzing with AFL) then you will want to enable coverage
769 for more specific subsets of files, and should say n here.
770
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771config DEBUG_SHIRQ
772 bool "Debug shared IRQ handlers"
Martin Schwidefsky0244ad02013-08-30 09:39:53 +0200773 depends on DEBUG_KERNEL
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 help
775 Enable this to generate a spurious interrupt as soon as a shared
776 interrupt handler is registered, and just before one is deregistered.
777 Drivers ought to be able to handle interrupts coming in at those
778 points; some don't and need to be caught.
779
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700780menu "Debug Lockups and Hangs"
781
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782config LOCKUP_DETECTOR
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700783 bool
784
785config SOFTLOCKUP_DETECTOR
786 bool "Detect Soft Lockups"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 depends on DEBUG_KERNEL && !S390
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700788 select LOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 help
790 Say Y here to enable the kernel to act as a watchdog to detect
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700791 soft lockups.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792
793 Softlockups are bugs that cause the kernel to loop in kernel
794 mode for more than 20 seconds, without giving other tasks a
795 chance to run. The current stack trace is displayed upon
796 detection and the system will stay locked up.
797
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700798config HARDLOCKUP_DETECTOR_PERF
799 bool
800 select SOFTLOCKUP_DETECTOR
801
802#
Thomas Gleixner7edaeb62017-08-15 09:50:13 +0200803# Enables a timestamp based low pass filter to compensate for perf based
804# hard lockup detection which runs too fast due to turbo modes.
805#
806config HARDLOCKUP_CHECK_TIMESTAMP
807 bool
808
809#
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700810# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
811# lockup detector rather than the perf based detector.
812#
813config HARDLOCKUP_DETECTOR
814 bool "Detect Hard Lockups"
815 depends on DEBUG_KERNEL && !S390
816 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
817 select LOCKUP_DETECTOR
818 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
819 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
820 help
821 Say Y here to enable the kernel to act as a watchdog to detect
822 hard lockups.
823
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 Hardlockups are bugs that cause the CPU to loop in kernel mode
825 for more than 10 seconds, without letting other interrupts have a
826 chance to run. The current stack trace is displayed upon detection
827 and the system will stay locked up.
828
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829config BOOTPARAM_HARDLOCKUP_PANIC
830 bool "Panic (Reboot) On Hard Lockups"
831 depends on HARDLOCKUP_DETECTOR
832 help
833 Say Y here to enable the kernel to panic on "hard lockups",
834 which are bugs that cause the kernel to loop in kernel
835 mode with interrupts disabled for more than 10 seconds (configurable
836 using the watchdog_thresh sysctl).
837
838 Say N if unsure.
839
840config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
841 int
842 depends on HARDLOCKUP_DETECTOR
843 range 0 1
844 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
845 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
846
847config BOOTPARAM_SOFTLOCKUP_PANIC
848 bool "Panic (Reboot) On Soft Lockups"
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700849 depends on SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 help
851 Say Y here to enable the kernel to panic on "soft lockups",
852 which are bugs that cause the kernel to loop in kernel
853 mode for more than 20 seconds (configurable using the watchdog_thresh
854 sysctl), without giving other tasks a chance to run.
855
856 The panic can be used in combination with panic_timeout,
857 to cause the system to reboot automatically after a
858 lockup has been detected. This feature is useful for
859 high-availability systems that have uptime guarantees and
860 where a lockup must be resolved ASAP.
861
862 Say N if unsure.
863
864config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
865 int
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700866 depends on SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700867 range 0 1
868 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
869 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
870
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871config DETECT_HUNG_TASK
872 bool "Detect Hung Tasks"
873 depends on DEBUG_KERNEL
Nicholas Piggin05a4a952017-07-12 14:35:46 -0700874 default SOFTLOCKUP_DETECTOR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 help
876 Say Y here to enable the kernel to detect "hung tasks",
877 which are bugs that cause the task to be stuck in
Vivien Didelot96b03ab2016-09-22 16:55:13 -0400878 uninterruptible "D" state indefinitely.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879
880 When a hung task is detected, the kernel will print the
881 current stack trace (which you should report), but the
882 task will stay in uninterruptible state. If lockdep is
883 enabled then all held locks will also be reported. This
884 feature has negligible overhead.
885
886config DEFAULT_HUNG_TASK_TIMEOUT
887 int "Default timeout for hung task detection (in seconds)"
888 depends on DETECT_HUNG_TASK
889 default 120
890 help
Ingo Molnar8637c092006-07-03 00:24:38 -0700891 This option controls the default timeout (in seconds) used
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 to determine when a task has become non-responsive and should
893 be considered hung.
894
895 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
896 sysctl or by writing a value to
897 /proc/sys/kernel/hung_task_timeout_secs.
898
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700899 A timeout of 0 disables the check. The default is two minutes.
900 Keeping the default should be fine in most cases.
Ingo Molnare7eebaf2006-06-27 02:54:55 -0700901
902config BOOTPARAM_HUNG_TASK_PANIC
903 bool "Panic (Reboot) On Hung Tasks"
904 depends on DETECT_HUNG_TASK
905 help
906 Say Y here to enable the kernel to panic on "hung tasks",
907 which are bugs that cause the kernel to leave a task stuck
908 in uninterruptible "D" state.
909
910 The panic can be used in combination with panic_timeout,
Thomas Gleixner61a87122006-06-27 02:54:56 -0700911 to cause the system to reboot automatically after a
912 hung task has been detected. This feature is useful for
Roman Zippela1583d32006-06-27 02:55:00 -0700913 high-availability systems that have uptime guarantees and
Thomas Gleixner61a87122006-06-27 02:54:56 -0700914 where a hung tasks must be resolved ASAP.
915
916 Say N if unsure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917
Hugh Dickins048c8bc2006-11-01 05:44:54 +1100918config BOOTPARAM_HUNG_TASK_PANIC_VALUE
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 int
920 depends on DETECT_HUNG_TASK
921 range 0 1
922 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
923 default 1 if BOOTPARAM_HUNG_TASK_PANIC
924
Tejun Heo82607adc2015-12-08 11:28:04 -0500925config WQ_WATCHDOG
926 bool "Detect Workqueue Stalls"
927 depends on DEBUG_KERNEL
928 help
929 Say Y here to enable stall detection on workqueues. If a
930 worker pool doesn't make forward progress on a pending work
931 item for over a given amount of time, 30s by default, a
932 warning message is printed along with dump of workqueue
933 state. This can be configured through kernel parameter
934 "workqueue.watchdog_thresh" and its sysfs counterpart.
935
Dave Hansen92aef8fb2013-07-01 13:04:50 -0700936endmenu # "Debug lockups and hangs"
937
938config PANIC_ON_OOPS
939 bool "Panic on Oops"
940 help
941 Say Y here to enable the kernel to panic when it oopses. This
942 has the same effect as setting oops=panic on the kernel command
943 line.
944
945 This feature is useful to ensure that the kernel does not do
946 anything erroneous after an oops which could result in data
947 corruption or other issues.
948
949 Say N if unsure.
950
951config PANIC_ON_OOPS_VALUE
952 int
953 range 0 1
954 default 0 if !PANIC_ON_OOPS
955 default 1 if PANIC_ON_OOPS
956
Jason Baron5800dc32013-11-25 23:23:04 +0000957config PANIC_TIMEOUT
958 int "panic timeout"
959 default 0
960 help
961 Set the timeout value (in seconds) until a reboot occurs when the
962 the kernel panics. If n = 0, then we wait forever. A timeout
963 value n > 0 will wait n seconds before rebooting, while a timeout
964 value n < 0 will reboot immediately.
965
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966config SCHED_DEBUG
967 bool "Collect scheduler debugging info"
968 depends on DEBUG_KERNEL && PROC_FS
969 default y
970 help
971 If you say Y here, the /proc/sched_debug file will be provided
972 that can help debug the scheduler. The runtime overhead of this
973 option is minimal.
974
Naveen N. Raof6db8342015-06-25 23:53:37 +0530975config SCHED_INFO
976 bool
977 default n
978
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979config SCHEDSTATS
980 bool "Collect scheduler statistics"
981 depends on DEBUG_KERNEL && PROC_FS
Naveen N. Raof6db8342015-06-25 23:53:37 +0530982 select SCHED_INFO
Linus Torvalds1da177e2005-04-16 15:20:36 -0700983 help
984 If you say Y here, additional code will be inserted into the
985 scheduler and related routines to collect statistics about
986 scheduler behavior and provide them in /proc/schedstat. These
987 stats may be useful for both tuning and debugging the scheduler
988 If you aren't debugging the scheduler or trying to tune a specific
989 application, you can say N to avoid the very slight overhead
990 this adds.
991
Aaron Tomlin0d9e2632014-09-12 14:16:19 +0100992config SCHED_STACK_END_CHECK
993 bool "Detect stack corruption on calls to schedule()"
994 depends on DEBUG_KERNEL
995 default n
996 help
997 This option checks for a stack overrun on calls to schedule().
998 If the stack end location is found to be over written always panic as
999 the content of the corrupted region can no longer be trusted.
1000 This is to ensure no erroneous behaviour occurs which could result in
1001 data corruption or a sporadic crash at a later stage once the region
1002 is examined. The runtime overhead introduced is minimal.
1003
John Stultz3c17ad12015-03-11 21:16:32 -07001004config DEBUG_TIMEKEEPING
1005 bool "Enable extra timekeeping sanity checking"
1006 help
1007 This option will enable additional timekeeping sanity checks
1008 which may be helpful when diagnosing issues where timekeeping
1009 problems are suspected.
1010
1011 This may include checks in the timekeeping hotpaths, so this
1012 option may have a (very small) performance impact to some
1013 workloads.
1014
1015 If unsure, say N.
1016
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017config DEBUG_PREEMPT
1018 bool "Debug preemptible kernel"
Kumar Gala01deab92009-10-16 07:21:39 +00001019 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020 default y
1021 help
1022 If you say Y here then the kernel will use a debug variant of the
1023 commonly used smp_processor_id() function and will print warnings
1024 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1025 will detect preemption count underflows.
1026
Dave Hansen9eade162013-07-01 13:04:47 -07001027menu "Lock Debugging (spinlocks, mutexes, etc...)"
1028
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029config DEBUG_RT_MUTEXES
1030 bool "RT Mutex debugging, deadlock detection"
1031 depends on DEBUG_KERNEL && RT_MUTEXES
1032 help
1033 This allows rt mutex semantics violations and rt mutex related
1034 deadlocks (lockups) to be detected and reported automatically.
1035
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036config DEBUG_SPINLOCK
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001037 bool "Spinlock and rw-lock debugging: basic checks"
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038 depends on DEBUG_KERNEL
Raghavendra K Te335e3e2012-03-22 15:25:08 +05301039 select UNINLINE_SPIN_UNLOCK
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 help
1041 Say Y here and build SMP to catch missing spinlock initialization
1042 and certain other kinds of spinlock errors commonly made. This is
1043 best used in conjunction with the NMI watchdog so that spinlock
1044 deadlocks are also debuggable.
1045
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001046config DEBUG_MUTEXES
1047 bool "Mutex debugging: basic checks"
1048 depends on DEBUG_KERNEL
1049 help
1050 This feature allows mutex semantics violations to be detected and
1051 reported.
1052
Daniel Vetter23010022013-06-20 13:31:17 +02001053config DEBUG_WW_MUTEX_SLOWPATH
1054 bool "Wait/wound mutex debugging: Slowpath testing"
1055 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1056 select DEBUG_LOCK_ALLOC
1057 select DEBUG_SPINLOCK
1058 select DEBUG_MUTEXES
1059 help
1060 This feature enables slowpath testing for w/w mutex users by
1061 injecting additional -EDEADLK wound/backoff cases. Together with
1062 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1063 will test all possible w/w mutex interface abuse with the
1064 exception of simply not acquiring all the required locks.
Rob Clark4d692372014-08-27 11:19:26 -04001065 Note that this feature can introduce significant overhead, so
1066 it really should not be enabled in a production or distro kernel,
1067 even a debug kernel. If you are a driver writer, enable it. If
1068 you are a distro, do not.
Daniel Vetter23010022013-06-20 13:31:17 +02001069
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001070config DEBUG_LOCK_ALLOC
1071 bool "Lock debugging: detect incorrect freeing of live locks"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001072 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001073 select DEBUG_SPINLOCK
1074 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001075 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001076 select LOCKDEP
1077 help
1078 This feature will check whether any held lock (spinlock, rwlock,
1079 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1080 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1081 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1082 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1083 held during task exit.
1084
1085config PROVE_LOCKING
1086 bool "Lock debugging: prove locking correctness"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001087 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001088 select LOCKDEP
1089 select DEBUG_SPINLOCK
1090 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001091 select DEBUG_RT_MUTEXES if RT_MUTEXES
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001092 select DEBUG_LOCK_ALLOC
Ingo Molnarb483cf3b2017-10-14 09:26:59 +02001093 select LOCKDEP_CROSSRELEASE if BROKEN
1094 select LOCKDEP_COMPLETIONS if BROKEN
Steven Rostedt46b93b72010-08-31 16:35:20 -04001095 select TRACE_IRQFLAGS
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001096 default n
1097 help
1098 This feature enables the kernel to prove that all locking
1099 that occurs in the kernel runtime is mathematically
1100 correct: that under no circumstance could an arbitrary (and
1101 not yet triggered) combination of observed locking
1102 sequences (on an arbitrary number of CPUs, running an
1103 arbitrary number of tasks and interrupt contexts) cause a
1104 deadlock.
1105
1106 In short, this feature enables the kernel to report locking
1107 related deadlocks before they actually occur.
1108
1109 The proof does not depend on how hard and complex a
1110 deadlock scenario would be to trigger: how many
1111 participant CPUs, tasks and irq-contexts would be needed
1112 for it to trigger. The proof also does not depend on
1113 timing: if a race and a resulting deadlock is possible
1114 theoretically (no matter how unlikely the race scenario
1115 is), it will be proven so and will immediately be
1116 reported by the kernel (once the event is observed that
1117 makes the deadlock theoretically possible).
1118
1119 If a deadlock is impossible (i.e. the locking rules, as
1120 observed by the kernel, are mathematically correct), the
1121 kernel reports nothing.
1122
1123 NOTE: this feature can also be enabled for rwlocks, mutexes
1124 and rwsems - in which case all dependencies between these
1125 different locking variants are observed and mapped too, and
1126 the proof of observed correctness is also maintained for an
1127 arbitrary combination of these separate locking variants.
1128
Davidlohr Bueso214e0ae2014-07-30 13:41:55 -07001129 For more details, see Documentation/locking/lockdep-design.txt.
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001130
1131config LOCKDEP
1132 bool
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001133 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001134 select STACKTRACE
Josh Poimboeufa34a7662017-07-24 18:36:58 -05001135 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 && !MICROBLAZE && !ARC && !SCORE && !X86
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001136 select KALLSYMS
1137 select KALLSYMS_ALL
1138
Daniel Jordan395102d2017-04-10 11:50:52 -04001139config LOCKDEP_SMALL
1140 bool
1141
Peter Zijlstraf20786f2007-07-19 01:48:56 -07001142config LOCK_STAT
Danny ter Haarfdfb8702007-09-24 21:24:43 -07001143 bool "Lock usage statistics"
Peter Zijlstraf20786f2007-07-19 01:48:56 -07001144 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1145 select LOCKDEP
1146 select DEBUG_SPINLOCK
1147 select DEBUG_MUTEXES
Peter Zijlstraf5694782016-09-19 12:15:37 +02001148 select DEBUG_RT_MUTEXES if RT_MUTEXES
Peter Zijlstraf20786f2007-07-19 01:48:56 -07001149 select DEBUG_LOCK_ALLOC
1150 default n
1151 help
1152 This feature enables tracking lock contention points
1153
Davidlohr Bueso214e0ae2014-07-30 13:41:55 -07001154 For more details, see Documentation/locking/lockstat.txt
Peter Zijlstraa560aa42007-10-07 00:24:33 -07001155
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +01001156 This also enables lock events required by "perf lock",
1157 subcommand of perf.
1158 If you want to use "perf lock", you also need to turn on
1159 CONFIG_EVENT_TRACING.
Hitoshi Mitake84c6f882010-02-04 16:08:15 +09001160
1161 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
Frederic Weisbeckerdd8b1cf2010-02-27 17:10:39 +01001162 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
Hitoshi Mitake84c6f882010-02-04 16:08:15 +09001163
Byungchul Parkb09be672017-08-07 16:12:52 +09001164config LOCKDEP_CROSSRELEASE
Ingo Molnare26f34a2017-08-17 12:48:29 +02001165 bool
Byungchul Parkb09be672017-08-07 16:12:52 +09001166 help
1167 This makes lockdep work for crosslock which is a lock allowed to
1168 be released in a different context from the acquisition context.
1169 Normally a lock must be released in the context acquiring the lock.
1170 However, relexing this constraint helps synchronization primitives
1171 such as page locks or completions can use the lock correctness
1172 detector, lockdep.
1173
Byungchul Parkea3f2c02017-08-17 17:57:41 +09001174config LOCKDEP_COMPLETIONS
Ingo Molnare26f34a2017-08-17 12:48:29 +02001175 bool
Byungchul Parkcd8084f2017-08-07 16:12:56 +09001176 help
1177 A deadlock caused by wait_for_completion() and complete() can be
1178 detected by lockdep using crossrelease feature.
1179
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001180config DEBUG_LOCKDEP
1181 bool "Lock dependency engine debugging"
Adrian Bunk517e7aa2006-07-14 00:24:32 -07001182 depends on DEBUG_KERNEL && LOCKDEP
Ingo Molnar4d9f34a2006-07-03 00:24:55 -07001183 help
1184 If you say Y here, the lock dependency engine will do
1185 additional runtime checks to debug itself, at the price
1186 of more runtime overhead.
1187
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001188config DEBUG_ATOMIC_SLEEP
1189 bool "Sleep inside atomic section checking"
Frederic Weisbeckere8f7c702011-06-08 01:51:02 +02001190 select PREEMPT_COUNT
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191 depends on DEBUG_KERNEL
1192 help
1193 If you say Y here, various routines which may sleep will become very
Frederic Weisbeckerd902db12011-06-08 19:31:56 +02001194 noisy if they are called inside atomic sections: when a spinlock is
1195 held, inside an rcu read side critical section, inside preempt disabled
1196 sections, inside an interrupt, etc...
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197
Ingo Molnarcae2ed92006-07-03 00:24:48 -07001198config DEBUG_LOCKING_API_SELFTESTS
1199 bool "Locking API boot-time self-tests"
1200 depends on DEBUG_KERNEL
1201 help
1202 Say Y here if you want the kernel to run a short self-test during
1203 bootup. The self-test checks whether common types of locking bugs
1204 are detected by debugging mechanisms or not. (if you disable
1205 lock debugging then those bugs wont be detected of course.)
1206 The following locking APIs are covered: spinlocks, rwlocks,
1207 mutexes and rwsems.
1208
Paul E. McKenney0af3fe12014-02-04 15:51:41 -08001209config LOCK_TORTURE_TEST
1210 tristate "torture tests for locking"
1211 depends on DEBUG_KERNEL
1212 select TORTURE_TEST
1213 default n
1214 help
1215 This option provides a kernel module that runs torture tests
1216 on kernel locking primitives. The kernel module may be built
1217 after the fact on the running kernel to be tested, if desired.
1218
1219 Say Y here if you want kernel locking-primitive torture tests
1220 to be built into the kernel.
1221 Say M if you want these torture tests to build as a module.
1222 Say N if you are unsure.
1223
Chris Wilsonf2a5fec2016-12-01 11:47:06 +00001224config WW_MUTEX_SELFTEST
1225 tristate "Wait/wound mutex selftests"
1226 help
1227 This option provides a kernel module that runs tests on the
1228 on the struct ww_mutex locking API.
1229
1230 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1231 with this test harness.
1232
1233 Say M if you want these self tests to build as a module.
1234 Say N if you are unsure.
1235
Dave Hansen9eade162013-07-01 13:04:47 -07001236endmenu # lock debugging
1237
1238config TRACE_IRQFLAGS
1239 bool
1240 help
1241 Enables hooks to interrupt enabling and disabling for
1242 either tracing or lock debugging.
1243
Ingo Molnar8637c092006-07-03 00:24:38 -07001244config STACKTRACE
Dave Jones0c38e1f2014-08-29 15:18:35 -07001245 bool "Stack backtrace support"
Ingo Molnar8637c092006-07-03 00:24:38 -07001246 depends on STACKTRACE_SUPPORT
Dave Jones0c38e1f2014-08-29 15:18:35 -07001247 help
1248 This option causes the kernel to create a /proc/pid/stack for
1249 every process, showing its current stack trace.
1250 It is also used by various kernel debugging features that require
1251 stack trace generation.
Ingo Molnar8637c092006-07-03 00:24:38 -07001252
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001253config WARN_ALL_UNSEEDED_RANDOM
1254 bool "Warn for all uses of unseeded randomness"
1255 default n
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001256 help
1257 Some parts of the kernel contain bugs relating to their use of
1258 cryptographically secure random numbers before it's actually possible
1259 to generate those numbers securely. This setting ensures that these
1260 flaws don't go unnoticed, by enabling a message, should this ever
1261 occur. This will allow people with obscure setups to know when things
1262 are going wrong, so that they might contact developers about fixing
1263 it.
1264
Theodore Ts'oeecabf52017-06-08 04:16:59 -04001265 Unfortunately, on some models of some architectures getting
1266 a fully seeded CRNG is extremely difficult, and so this can
1267 result in dmesg getting spammed for a surprisingly long
1268 time. This is really bad from a security perspective, and
1269 so architecture maintainers really need to do what they can
1270 to get the CRNG seeded sooner after the system is booted.
1271 However, since users can not do anything actionble to
1272 address this, by default the kernel will issue only a single
1273 warning for the first use of unseeded randomness.
1274
1275 Say Y here if you want to receive warnings for all uses of
1276 unseeded randomness. This will be of use primarily for
1277 those developers interersted in improving the security of
1278 Linux kernels running on their architecture (or
1279 subarchitecture).
Jason A. Donenfeldd06bfd12017-06-07 23:06:55 -04001280
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281config DEBUG_KOBJECT
1282 bool "kobject debugging"
1283 depends on DEBUG_KERNEL
1284 help
1285 If you say Y here, some extra kobject debugging messages will be sent
1286 to the syslog.
1287
Russell Kingc817a672013-06-27 15:06:14 +01001288config DEBUG_KOBJECT_RELEASE
1289 bool "kobject release debugging"
Linus Torvalds2a999aa2013-10-29 08:33:36 -07001290 depends on DEBUG_OBJECTS_TIMERS
Russell Kingc817a672013-06-27 15:06:14 +01001291 help
1292 kobjects are reference counted objects. This means that their
1293 last reference count put is not predictable, and the kobject can
1294 live on past the point at which a driver decides to drop it's
1295 initial reference to the kobject gained on allocation. An
1296 example of this would be a struct device which has just been
1297 unregistered.
1298
1299 However, some buggy drivers assume that after such an operation,
1300 the memory backing the kobject can be immediately freed. This
1301 goes completely against the principles of a refcounted object.
1302
1303 If you say Y here, the kernel will delay the release of kobjects
1304 on the last reference count to improve the visibility of this
1305 kind of kobject release bug.
1306
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001307config HAVE_DEBUG_BUGVERBOSE
1308 bool
1309
Linus Torvalds1da177e2005-04-16 15:20:36 -07001310config DEBUG_BUGVERBOSE
David Rientjes6a108a12011-01-20 14:44:16 -08001311 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
Catalin Marinas9b2a60c2012-10-08 16:28:13 -07001312 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
Alexey Dobriyan8420e7e2009-12-14 18:00:25 -08001313 default y
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 help
1315 Say Y here to make BUG() panics output the file name and line number
1316 of the BUG call as well as the EIP and oops trace. This aids
1317 debugging but costs about 70-100K of memory.
1318
Dave Jones199a9af2006-09-29 01:59:00 -07001319config DEBUG_LIST
1320 bool "Debug linked list manipulation"
Arnd Bergmann4520bcb2016-08-26 17:42:00 +02001321 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
Dave Jones199a9af2006-09-29 01:59:00 -07001322 help
1323 Enable this to turn on extended checks in the linked-list
1324 walking routines.
1325
1326 If unsure, say N.
1327
Dan Streetmanb8cfff62014-06-04 16:11:54 -07001328config DEBUG_PI_LIST
1329 bool "Debug priority linked list manipulation"
1330 depends on DEBUG_KERNEL
1331 help
1332 Enable this to turn on extended checks in the priority-ordered
1333 linked-list (plist) walking routines. This checks the entire
1334 list multiple times during each manipulation.
1335
1336 If unsure, say N.
1337
Jens Axboed6ec0842007-10-22 20:01:06 +02001338config DEBUG_SG
1339 bool "Debug SG table operations"
1340 depends on DEBUG_KERNEL
1341 help
1342 Enable this to turn on checks on scatter-gather tables. This can
1343 help find problems with drivers that do not properly initialize
1344 their sg tables.
1345
1346 If unsure, say N.
1347
Arjan van de Ven1b2439d2008-08-15 15:29:38 -07001348config DEBUG_NOTIFIERS
1349 bool "Debug notifier call chains"
1350 depends on DEBUG_KERNEL
1351 help
1352 Enable this to turn on sanity checking for notifier call chains.
1353 This is most useful for kernel developers to make sure that
1354 modules properly unregister themselves from notifier chains.
1355 This is a relatively cheap check but if you care about maximum
1356 performance, say N.
1357
David Howellse0e81732009-09-02 09:13:40 +01001358config DEBUG_CREDENTIALS
1359 bool "Debug credential management"
1360 depends on DEBUG_KERNEL
1361 help
1362 Enable this to turn on some debug checking for credential
1363 management. The additional code keeps track of the number of
1364 pointers from task_structs to any given cred struct, and checks to
1365 see that this number never exceeds the usage count of the cred
1366 struct.
1367
1368 Furthermore, if SELinux is enabled, this also checks that the
1369 security pointer in the cred struct is never seen to be invalid.
1370
1371 If unsure, say N.
1372
Paul E. McKenney43a0a2a2017-05-17 09:19:44 -07001373source "kernel/rcu/Kconfig.debug"
Dave Hansen2f03e3c2013-01-07 08:19:23 -08001374
Tejun Heof303fcc2016-02-09 17:59:38 -05001375config DEBUG_WQ_FORCE_RR_CPU
1376 bool "Force round-robin CPU selection for unbound work items"
1377 depends on DEBUG_KERNEL
1378 default n
1379 help
1380 Workqueue used to implicitly guarantee that work items queued
1381 without explicit CPU specified are put on the local CPU. This
1382 guarantee is no longer true and while local CPU is still
1383 preferred work items may be put on foreign CPUs. Kernel
1384 parameter "workqueue.debug_force_rr_cpu" is added to force
1385 round-robin CPU selection to flush out usages which depend on the
1386 now broken guarantee. This config option enables the debug
1387 feature by default. When enabled, memory and cache locality will
1388 be impacted.
1389
Tejun Heo870d6652008-08-25 19:47:25 +09001390config DEBUG_BLOCK_EXT_DEVT
1391 bool "Force extended block device numbers and spread them"
1392 depends on DEBUG_KERNEL
1393 depends on BLOCK
Jens Axboe759f8ca2008-08-29 09:06:29 +02001394 default n
Tejun Heo870d6652008-08-25 19:47:25 +09001395 help
Tejun Heo0e11e342008-10-13 10:46:01 +02001396 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1397 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1398 YOU ARE DOING. Distros, please enable this and fix whatever
1399 is broken.
1400
Tejun Heo870d6652008-08-25 19:47:25 +09001401 Conventionally, block device numbers are allocated from
1402 predetermined contiguous area. However, extended block area
1403 may introduce non-contiguous block device numbers. This
1404 option forces most block device numbers to be allocated from
1405 the extended space and spreads them to discover kernel or
1406 userland code paths which assume predetermined contiguous
1407 device number allocation.
1408
Tejun Heo55dc7db2008-09-01 13:44:35 +02001409 Note that turning on this debug option shuffles all the
1410 device numbers for all IDE and SCSI devices including libata
1411 ones, so root partition specified using device number
1412 directly (via rdev or root=MAJ:MIN) won't work anymore.
1413 Textual device names (root=/dev/sdXn) will continue to work.
1414
Tejun Heo870d6652008-08-25 19:47:25 +09001415 Say N if you are unsure.
1416
Thomas Gleixner757c9892016-02-26 18:43:32 +00001417config CPU_HOTPLUG_STATE_CONTROL
1418 bool "Enable CPU hotplug state control"
1419 depends on DEBUG_KERNEL
1420 depends on HOTPLUG_CPU
1421 default n
1422 help
1423 Allows to write steps between "offline" and "online" to the CPUs
1424 sysfs target file so states can be stepped granular. This is a debug
1425 option for now as the hotplug machinery cannot be stopped and
1426 restarted at arbitrary points yet.
1427
1428 Say N if your are unsure.
1429
Akinobu Mita8d438282012-07-30 14:43:02 -07001430config NOTIFIER_ERROR_INJECTION
1431 tristate "Notifier error injection"
1432 depends on DEBUG_KERNEL
1433 select DEBUG_FS
1434 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001435 This option provides the ability to inject artificial errors to
Akinobu Mita8d438282012-07-30 14:43:02 -07001436 specified notifier chain callbacks. It is useful to test the error
1437 handling of notifier call chain failures.
1438
1439 Say N if unsure.
1440
Akinobu Mita048b9c32012-07-30 14:43:07 -07001441config PM_NOTIFIER_ERROR_INJECT
1442 tristate "PM notifier error injection module"
1443 depends on PM && NOTIFIER_ERROR_INJECTION
1444 default m if PM_DEBUG
1445 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001446 This option provides the ability to inject artificial errors to
Akinobu Mita048b9c32012-07-30 14:43:07 -07001447 PM notifier chain callbacks. It is controlled through debugfs
1448 interface /sys/kernel/debug/notifier-error-inject/pm
1449
1450 If the notifier call chain should be failed with some events
1451 notified, write the error code to "actions/<notifier event>/error".
1452
1453 Example: Inject PM suspend error (-12 = -ENOMEM)
1454
1455 # cd /sys/kernel/debug/notifier-error-inject/pm/
1456 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1457 # echo mem > /sys/power/state
1458 bash: echo: write error: Cannot allocate memory
1459
1460 To compile this code as a module, choose M here: the module will
1461 be called pm-notifier-error-inject.
1462
1463 If unsure, say N.
1464
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001465config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1466 tristate "OF reconfig notifier error injection module"
1467 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001468 help
Masanari Iidae41e85c2012-11-30 16:44:39 +09001469 This option provides the ability to inject artificial errors to
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001470 OF reconfig notifier chain callbacks. It is controlled
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001471 through debugfs interface under
Benjamin Herrenschmidtd526e852012-12-14 10:32:52 +11001472 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001473
1474 If the notifier call chain should be failed with some events
1475 notified, write the error code to "actions/<notifier event>/error".
1476
1477 To compile this code as a module, choose M here: the module will
Akinobu Mitae12a95f2013-04-30 15:28:49 -07001478 be called of-reconfig-notifier-error-inject.
Akinobu Mita08dfb4d2012-07-30 14:43:13 -07001479
1480 If unsure, say N.
1481
Nikolay Aleksandrov02fff962015-11-28 13:45:28 +01001482config NETDEV_NOTIFIER_ERROR_INJECT
1483 tristate "Netdev notifier error injection module"
1484 depends on NET && NOTIFIER_ERROR_INJECTION
1485 help
1486 This option provides the ability to inject artificial errors to
1487 netdevice notifier chain callbacks. It is controlled through debugfs
1488 interface /sys/kernel/debug/notifier-error-inject/netdev
1489
1490 If the notifier call chain should be failed with some events
1491 notified, write the error code to "actions/<notifier event>/error".
1492
1493 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1494
1495 # cd /sys/kernel/debug/notifier-error-inject/netdev
1496 # echo -22 > actions/NETDEV_CHANGEMTU/error
1497 # ip link set eth0 mtu 1024
1498 RTNETLINK answers: Invalid argument
1499
1500 To compile this code as a module, choose M here: the module will
1501 be called netdev-notifier-error-inject.
1502
1503 If unsure, say N.
1504
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001505config FAULT_INJECTION
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001506 bool "Fault-injection framework"
1507 depends on DEBUG_KERNEL
Akinobu Mita329409a2006-12-08 02:39:48 -08001508 help
1509 Provide fault-injection framework.
1510 For more details, see Documentation/fault-injection/.
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001511
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001512config FAILSLAB
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001513 bool "Fault-injection capability for kmalloc"
1514 depends on FAULT_INJECTION
Akinobu Mita773ff602008-12-23 19:37:01 +09001515 depends on SLAB || SLUB
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001516 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001517 Provide fault-injection capability for kmalloc.
Akinobu Mita8a8b6502006-12-08 02:39:44 -08001518
Akinobu Mita933e3122006-12-08 02:39:45 -08001519config FAIL_PAGE_ALLOC
1520 bool "Fault-injection capabilitiy for alloc_pages()"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001521 depends on FAULT_INJECTION
Akinobu Mita933e3122006-12-08 02:39:45 -08001522 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001523 Provide fault-injection capability for alloc_pages().
Akinobu Mita933e3122006-12-08 02:39:45 -08001524
Akinobu Mitac17bb492006-12-08 02:39:46 -08001525config FAIL_MAKE_REQUEST
Dave Jones86327d12006-12-12 20:16:36 +01001526 bool "Fault-injection capability for disk IO"
Jens Axboe581d4e22008-09-14 05:56:33 -07001527 depends on FAULT_INJECTION && BLOCK
Akinobu Mitac17bb492006-12-08 02:39:46 -08001528 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001529 Provide fault-injection capability for disk IO.
Akinobu Mitac17bb492006-12-08 02:39:46 -08001530
Jens Axboe581d4e22008-09-14 05:56:33 -07001531config FAIL_IO_TIMEOUT
Takuya Yoshikawaf4d014392010-07-21 16:05:53 +09001532 bool "Fault-injection capability for faking disk interrupts"
Jens Axboe581d4e22008-09-14 05:56:33 -07001533 depends on FAULT_INJECTION && BLOCK
1534 help
1535 Provide fault-injection capability on end IO handling. This
1536 will make the block layer "forget" an interrupt as configured,
1537 thus exercising the error handling.
1538
1539 Only works with drivers that use the generic timeout handling,
1540 for others it wont do anything.
1541
Per Forlin1b676f72011-08-19 14:52:37 +02001542config FAIL_MMC_REQUEST
1543 bool "Fault-injection capability for MMC IO"
Adrien Schildknecht28ff4fd2015-11-10 20:12:19 +01001544 depends on FAULT_INJECTION_DEBUG_FS && MMC
Per Forlin1b676f72011-08-19 14:52:37 +02001545 help
1546 Provide fault-injection capability for MMC IO.
1547 This will make the mmc core return data errors. This is
1548 useful to test the error handling in the mmc block device
1549 and to test how the mmc host driver handles retries from
1550 the block device.
1551
Davidlohr Buesoab51fba2015-06-29 23:26:02 -07001552config FAIL_FUTEX
1553 bool "Fault-injection capability for futexes"
1554 select DEBUG_FS
1555 depends on FAULT_INJECTION && FUTEX
1556 help
1557 Provide fault-injection capability for futexes.
1558
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001559config FAULT_INJECTION_DEBUG_FS
1560 bool "Debugfs entries for fault-injection capabilities"
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001561 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
Akinobu Mita6ff1cb32006-12-08 02:39:43 -08001562 help
Andrew Morton1ab8509a2006-12-08 02:39:49 -08001563 Enable configuration of fault-injection capabilities via debugfs.
Akinobu Mita1df49002007-02-20 13:57:56 -08001564
1565config FAULT_INJECTION_STACKTRACE_FILTER
1566 bool "stacktrace filter for fault-injection capabilities"
1567 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
Akinobu Mita6d690dc2007-05-12 10:36:53 -07001568 depends on !X86_64
Akinobu Mita1df49002007-02-20 13:57:56 -08001569 select STACKTRACE
Josh Poimboeufa34a7662017-07-24 18:36:58 -05001570 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !SCORE && !X86
Akinobu Mita1df49002007-02-20 13:57:56 -08001571 help
1572 Provide stacktrace filter for fault-injection capabilities
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001573
Arjan van de Ven97455122008-01-25 21:08:34 +01001574config LATENCYTOP
1575 bool "Latency measuring infrastructure"
Randy Dunlap625fdca2010-08-12 12:31:21 -07001576 depends on DEBUG_KERNEL
1577 depends on STACKTRACE_SUPPORT
1578 depends on PROC_FS
Josh Poimboeufa34a7662017-07-24 18:36:58 -05001579 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM_UNWIND && !ARC && !X86
Arjan van de Ven97455122008-01-25 21:08:34 +01001580 select KALLSYMS
1581 select KALLSYMS_ALL
1582 select STACKTRACE
1583 select SCHEDSTATS
1584 select SCHED_DEBUG
Arjan van de Ven97455122008-01-25 21:08:34 +01001585 help
1586 Enable this option if you want to use the LatencyTOP tool
1587 to find out which userspace is blocking on what kernel operations.
1588
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02001589source kernel/trace/Kconfig
1590
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001591config PROVIDE_OHCI1394_DMA_INIT
1592 bool "Remote debugging over FireWire early on boot"
1593 depends on PCI && X86
1594 help
1595 If you want to debug problems which hang or crash the kernel early
1596 on boot and the crashing machine has a FireWire port, you can use
1597 this feature to remotely access the memory of the crashed machine
1598 over FireWire. This employs remote DMA as part of the OHCI1394
1599 specification which is now the standard for FireWire controllers.
1600
1601 With remote DMA, you can monitor the printk buffer remotely using
1602 firescope and access all memory below 4GB using fireproxy from gdb.
1603 Even controlling a kernel debugger is possible using remote DMA.
1604
1605 Usage:
1606
1607 If ohci1394_dma=early is used as boot parameter, it will initialize
1608 all OHCI1394 controllers which are found in the PCI config space.
1609
1610 As all changes to the FireWire bus such as enabling and disabling
1611 devices cause a bus reset and thereby disable remote DMA for all
1612 devices, be sure to have the cable plugged and FireWire enabled on
1613 the debugging host before booting the debug target for debugging.
1614
1615 This code (~1k) is freed after boot. By then, the firewire stack
1616 in charge of the OHCI-1394 controllers should be used instead.
1617
1618 See Documentation/debugging-via-ohci1394.txt for more information.
1619
1620config DMA_API_DEBUG
1621 bool "Enable debugging of DMA-API usage"
1622 depends on HAVE_DMA_API_DEBUG
1623 help
1624 Enable this option to debug the use of the DMA API by device drivers.
1625 With this option you will be able to detect common bugs in device
1626 drivers like double-freeing of DMA mappings or freeing mappings that
1627 were never allocated.
1628
1629 This also attempts to catch cases where a page owned by DMA is
1630 accessed by the cpu in a way that could cause data corruption. For
1631 example, this enables cow_user_page() to check that the source page is
1632 not undergoing DMA.
1633
1634 This option causes a performance degradation. Use only if you want to
1635 debug device drivers and dma interactions.
1636
1637 If unsure, say N.
1638
Dave Hansen881c5142013-07-01 13:04:44 -07001639menu "Runtime Testing"
1640
1641config LKDTM
1642 tristate "Linux Kernel Dump Test Tool Module"
1643 depends on DEBUG_FS
1644 depends on BLOCK
1645 default n
1646 help
1647 This module enables testing of the different dumping mechanisms by
1648 inducing system failures at predefined crash points.
1649 If you don't need it: say N
1650 Choose M here to compile this code as a module. The module will be
1651 called lkdtm.
1652
1653 Documentation on how to use the module can be found in
1654 Documentation/fault-injection/provoke-crashes.txt
1655
1656config TEST_LIST_SORT
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001657 tristate "Linked list sorting test"
1658 depends on DEBUG_KERNEL || m
Dave Hansen881c5142013-07-01 13:04:44 -07001659 help
1660 Enable this to turn on 'list_sort()' function test. This test is
Geert Uytterhoevene327fd72017-05-08 15:55:26 -07001661 executed only once during system boot (so affects only boot time),
1662 or at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001663
1664 If unsure, say N.
1665
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001666config TEST_SORT
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001667 tristate "Array-based sort test"
1668 depends on DEBUG_KERNEL || m
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001669 help
Geert Uytterhoeven5c4e6792017-05-08 15:55:23 -07001670 This option enables the self-test function of 'sort()' at boot,
1671 or at module load time.
Kostenzer Felixc5adae92017-02-24 15:01:07 -08001672
1673 If unsure, say N.
1674
Dave Hansen881c5142013-07-01 13:04:44 -07001675config KPROBES_SANITY_TEST
1676 bool "Kprobes sanity tests"
1677 depends on DEBUG_KERNEL
1678 depends on KPROBES
1679 default n
1680 help
1681 This option provides for testing basic kprobes functionality on
1682 boot. A sample kprobe, jprobe and kretprobe are inserted and
1683 verified for functionality.
1684
1685 Say N if you are unsure.
1686
1687config BACKTRACE_SELF_TEST
1688 tristate "Self test for the backtrace code"
1689 depends on DEBUG_KERNEL
1690 default n
1691 help
1692 This option provides a kernel module that can be used to test
1693 the kernel stack backtrace code. This option is not useful
1694 for distributions or general kernels, but only for kernel
1695 developers working on architecture code.
1696
1697 Note that if you want to also test saved backtraces, you will
1698 have to enable STACKTRACE as well.
1699
1700 Say N if you are unsure.
1701
Michel Lespinasse910a7422012-10-08 16:30:39 -07001702config RBTREE_TEST
1703 tristate "Red-Black tree test"
Cody P Schafer7c993e12013-09-11 14:25:19 -07001704 depends on DEBUG_KERNEL
Michel Lespinasse910a7422012-10-08 16:30:39 -07001705 help
1706 A benchmark measuring the performance of the rbtree library.
1707 Also includes rbtree invariant checks.
1708
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001709config INTERVAL_TREE_TEST
1710 tristate "Interval tree test"
Davidlohr Bueso0f789b62017-07-10 15:51:43 -07001711 depends on DEBUG_KERNEL
Chris Wilsona88cc102014-03-17 12:21:54 +00001712 select INTERVAL_TREE
Michel Lespinassefff3fd82012-10-08 16:31:23 -07001713 help
1714 A benchmark measuring the performance of the interval tree library
1715
Greg Thelen623fd802013-11-12 15:08:34 -08001716config PERCPU_TEST
1717 tristate "Per cpu operations test"
1718 depends on m && DEBUG_KERNEL
1719 help
1720 Enable this option to build test module which validates per-cpu
1721 operations.
1722
1723 If unsure, say N.
1724
Dave Hansen881c5142013-07-01 13:04:44 -07001725config ATOMIC64_SELFTEST
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001726 tristate "Perform an atomic64_t self-test"
Dave Hansen881c5142013-07-01 13:04:44 -07001727 help
Geert Uytterhoeven55ded952017-02-24 15:00:55 -08001728 Enable this option to test the atomic64_t functions at boot or
1729 at module load time.
Dave Hansen881c5142013-07-01 13:04:44 -07001730
1731 If unsure, say N.
1732
1733config ASYNC_RAID6_TEST
1734 tristate "Self test for hardware accelerated raid6 recovery"
1735 depends on ASYNC_RAID6_RECOV
1736 select ASYNC_MEMCPY
1737 ---help---
1738 This is a one-shot self test that permutes through the
1739 recovery of all the possible two disk failure scenarios for a
1740 N-disk array. Recovery is performed with the asynchronous
1741 raid6 recovery routines, and will optionally use an offload
1742 engine if one is available.
1743
1744 If unsure, say N.
1745
Andy Shevchenko64d1d772015-02-12 15:02:21 -08001746config TEST_HEXDUMP
1747 tristate "Test functions located in the hexdump module at runtime"
1748
Dave Hansen881c5142013-07-01 13:04:44 -07001749config TEST_STRING_HELPERS
1750 tristate "Test functions located in the string_helpers module at runtime"
1751
1752config TEST_KSTRTOX
1753 tristate "Test kstrto*() family of functions at runtime"
1754
Rasmus Villemoes707cc722015-11-06 16:30:29 -08001755config TEST_PRINTF
1756 tristate "Test printf() family of functions at runtime"
1757
David Decotigny5fd003f2016-02-19 09:24:00 -05001758config TEST_BITMAP
1759 tristate "Test bitmap_*() family of functions at runtime"
1760 default n
1761 help
1762 Enable this option to test the bitmap functions at boot.
1763
1764 If unsure, say N.
1765
Andy Shevchenkocfaff0e2016-05-30 17:40:41 +03001766config TEST_UUID
1767 tristate "Test functions located in the uuid module at runtime"
1768
Thomas Graf7e1e7762014-08-02 11:47:44 +02001769config TEST_RHASHTABLE
Geert Uytterhoeven9d6dbe12015-01-29 15:40:25 +01001770 tristate "Perform selftest on resizable hash table"
Thomas Graf7e1e7762014-08-02 11:47:44 +02001771 default n
1772 help
1773 Enable this option to test the rhashtable functions at boot.
1774
1775 If unsure, say N.
1776
George Spelvin468a9422016-05-26 22:11:51 -04001777config TEST_HASH
1778 tristate "Perform selftest on hash functions"
1779 default n
1780 help
Jason A. Donenfeld2c956a62017-01-08 13:54:00 +01001781 Enable this option to test the kernel's integer (<linux/hash.h>),
1782 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1783 hash functions on boot (or module load).
George Spelvin468a9422016-05-26 22:11:51 -04001784
1785 This is intended to help people writing architecture-specific
1786 optimized versions. If unsure, say N.
1787
Jiri Pirko44091d22017-02-03 10:29:06 +01001788config TEST_PARMAN
1789 tristate "Perform selftest on priority array manager"
1790 default n
1791 depends on PARMAN
1792 help
1793 Enable this option to test priority array manager on boot
1794 (or module load).
1795
1796 If unsure, say N.
1797
Valentin Rothberg8a6f0b42014-10-13 15:51:38 -07001798config TEST_LKM
Kees Cook93e9ef82014-01-23 15:54:37 -08001799 tristate "Test module loading with 'hello world' module"
1800 default n
1801 depends on m
1802 help
1803 This builds the "test_module" module that emits "Hello, world"
1804 on printk when loaded. It is designed to be used for basic
1805 evaluation of the module loading subsystem (for example when
1806 validating module verification). It lacks any extra dependencies,
1807 and will not normally be loaded by the system unless explicitly
1808 requested by name.
1809
1810 If unsure, say N.
1811
Kees Cook3e2a4c12014-01-23 15:54:38 -08001812config TEST_USER_COPY
1813 tristate "Test user/kernel boundary protections"
1814 default n
1815 depends on m
1816 help
1817 This builds the "test_user_copy" module that runs sanity checks
1818 on the copy_to/from_user infrastructure, making sure basic
1819 user/kernel boundary testing is working. If it fails to load,
1820 a regression has been detected in the user/kernel memory boundary
1821 protections.
1822
1823 If unsure, say N.
1824
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001825config TEST_BPF
1826 tristate "Test BPF filter functionality"
1827 default n
Randy Dunlap98920ba2014-05-13 09:58:44 -07001828 depends on m && NET
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001829 help
1830 This builds the "test_bpf" module that runs various test vectors
1831 against the BPF interpreter or BPF JIT compiler depending on the
1832 current setting. This is in particular useful for BPF JIT compiler
1833 development, but also to run regression tests against changes in
Alexei Starovoitov3c731eb2014-09-26 00:17:07 -07001834 the interpreter code. It also enables test stubs for eBPF maps and
1835 verifier used by user space verifier testsuite.
Alexei Starovoitov64a89462014-05-08 14:10:52 -07001836
1837 If unsure, say N.
1838
Kees Cook0a8adf52014-07-14 14:38:12 -07001839config TEST_FIRMWARE
1840 tristate "Test firmware loading via userspace interface"
1841 default n
1842 depends on FW_LOADER
1843 help
1844 This builds the "test_firmware" module that creates a userspace
1845 interface for testing firmware loading. This can be used to
1846 control the triggering of firmware loading without needing an
1847 actual firmware-using device. The contents can be rechecked by
1848 userspace.
1849
1850 If unsure, say N.
1851
Luis R. Rodriguez9308f2f2017-07-12 14:33:43 -07001852config TEST_SYSCTL
1853 tristate "sysctl test driver"
1854 default n
1855 depends on PROC_SYSCTL
1856 help
1857 This builds the "test_sysctl" module. This driver enables to test the
1858 proc sysctl interfaces available to drivers safely without affecting
1859 production knobs which might alter system functionality.
1860
1861 If unsure, say N.
1862
David Rileye704f932014-06-16 14:58:32 -07001863config TEST_UDELAY
1864 tristate "udelay test driver"
1865 default n
1866 help
1867 This builds the "udelay_test" module that helps to make sure
1868 that udelay() is working properly.
1869
1870 If unsure, say N.
1871
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02001872config TEST_STATIC_KEYS
1873 tristate "Test static keys"
Jason Baron579e1ac2015-07-30 03:59:44 +00001874 default n
1875 depends on m
1876 help
Ingo Molnar2bf9e0a2015-08-03 11:42:57 +02001877 Test the static key interfaces.
Jason Baron579e1ac2015-07-30 03:59:44 +00001878
1879 If unsure, say N.
1880
Luis R. Rodriguezd9c6a722017-07-14 14:50:08 -07001881config TEST_KMOD
1882 tristate "kmod stress tester"
1883 default n
1884 depends on m
1885 depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS
1886 depends on NETDEVICES && NET_CORE && INET # for TUN
1887 select TEST_LKM
1888 select XFS_FS
1889 select TUN
1890 select BTRFS_FS
1891 help
1892 Test the kernel's module loading mechanism: kmod. kmod implements
1893 support to load modules using the Linux kernel's usermode helper.
1894 This test provides a series of tests against kmod.
1895
1896 Although technically you can either build test_kmod as a module or
1897 into the kernel we disallow building it into the kernel since
1898 it stress tests request_module() and this will very likely cause
1899 some issues by taking over precious threads available from other
1900 module load requests, ultimately this could be fatal.
1901
1902 To run tests run:
1903
1904 tools/testing/selftests/kmod/kmod.sh --help
1905
1906 If unsure, say N.
1907
Florian Fainellie4dace32017-09-08 16:15:31 -07001908config TEST_DEBUG_VIRTUAL
1909 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
1910 depends on DEBUG_VIRTUAL
1911 help
1912 Test the kernel's ability to detect incorrect calls to
1913 virt_to_phys() done against the non-linear part of the
1914 kernel's virtual address map.
1915
1916 If unsure, say N.
1917
Randy Dunlapcc3fa842017-10-13 15:57:33 -07001918endmenu # runtime tests
1919
1920config MEMTEST
1921 bool "Memtest"
1922 depends on HAVE_MEMBLOCK
1923 ---help---
1924 This option adds a kernel parameter 'memtest', which allows memtest
1925 to be set.
1926 memtest=0, mean disabled; -- default
1927 memtest=1, mean do 1 test pattern;
1928 ...
1929 memtest=17, mean do 17 test patterns.
1930 If you are unsure how to answer this question, answer N.
1931
1932config BUG_ON_DATA_CORRUPTION
1933 bool "Trigger a BUG when data corruption is detected"
1934 select DEBUG_LIST
1935 help
1936 Select this option if the kernel should BUG when it encounters
1937 data corruption in kernel memory structures when they get checked
1938 for validity.
1939
1940 If unsure, say N.
Florian Fainellie4dace32017-09-08 16:15:31 -07001941
Mathieu Desnoyers267c4022007-10-18 23:41:07 -07001942source "samples/Kconfig"
Jason Wesseldc7d5522008-04-17 20:05:37 +02001943
1944source "lib/Kconfig.kgdb"
Pekka Enberg0a4af3b2009-02-26 21:38:56 +02001945
Andrey Ryabininc6d30852016-01-20 15:00:55 -08001946source "lib/Kconfig.ubsan"
1947
Dan Williams21266be2015-11-19 18:19:29 -08001948config ARCH_HAS_DEVMEM_IS_ALLOWED
1949 bool
1950
1951config STRICT_DEVMEM
1952 bool "Filter access to /dev/mem"
Dave Young6b2a65c2016-12-12 16:46:14 -08001953 depends on MMU && DEVMEM
Dan Williams21266be2015-11-19 18:19:29 -08001954 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1955 default y if TILE || PPC
1956 ---help---
1957 If this option is disabled, you allow userspace (root) access to all
1958 of memory, including kernel and userspace memory. Accidental
1959 access to this is obviously disastrous, but specific access can
1960 be used by people debugging the kernel. Note that with PAT support
1961 enabled, even in this case there are restrictions on /dev/mem
1962 use due to the cache aliasing requirements.
1963
Dan Williams90a545e2015-11-23 15:49:03 -08001964 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1965 file only allows userspace access to PCI space and the BIOS code and
1966 data regions. This is sufficient for dosemu and X and all common
1967 users of /dev/mem.
1968
1969 If in doubt, say Y.
1970
1971config IO_STRICT_DEVMEM
1972 bool "Filter I/O access to /dev/mem"
1973 depends on STRICT_DEVMEM
Dan Williams90a545e2015-11-23 15:49:03 -08001974 ---help---
1975 If this option is disabled, you allow userspace (root) access to all
1976 io-memory regardless of whether a driver is actively using that
1977 range. Accidental access to this is obviously disastrous, but
1978 specific access can be used by people debugging kernel drivers.
1979
Dan Williams21266be2015-11-19 18:19:29 -08001980 If this option is switched on, the /dev/mem file only allows
Dan Williams90a545e2015-11-23 15:49:03 -08001981 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1982 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1983 if the driver using a given range cannot be disabled.
Dan Williams21266be2015-11-19 18:19:29 -08001984
1985 If in doubt, say Y.