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ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2menu "Kernel hacking"
3
604ff0dc 4menu "printk and dmesg options"
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5
6config PRINTK_TIME
7 bool "Show timing information on printks"
d3b8b6e5 8 depends on PRINTK
1da177e4 9 help
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10 Selecting this option causes time stamps of the printk()
11 messages to be added to the output of the syslog() system
12 call and at the console.
13
14 The timestamp is always recorded internally, and exported
15 to /dev/kmsg. This flag just specifies if the timestamp should
16 be included, not that the timestamp is recorded.
17
18 The behavior is also controlled by the kernel command line
8c27ceff 19 parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
1da177e4 20
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21config PRINTK_CALLER
22 bool "Show caller information on printks"
23 depends on PRINTK
24 help
25 Selecting this option causes printk() to add a caller "thread id" (if
26 in task context) or a caller "processor id" (if not in task context)
27 to every message.
28
29 This option is intended for environments where multiple threads
30 concurrently call printk() for many times, for it is difficult to
31 interpret without knowing where these lines (or sometimes individual
32 line which was divided into multiple lines due to race) came from.
33
34 Since toggling after boot makes the code racy, currently there is
35 no option to enable/disable at the kernel command line parameter or
36 sysfs interface.
37
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38config CONSOLE_LOGLEVEL_DEFAULT
39 int "Default console loglevel (1-15)"
40 range 1 15
41 default "7"
42 help
43 Default loglevel to determine what will be printed on the console.
44
45 Setting a default here is equivalent to passing in loglevel=<x> in
46 the kernel bootargs. loglevel=<x> continues to override whatever
47 value is specified here as well.
48
50f4d9bd 49 Note: This does not affect the log level of un-prefixed printk()
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50 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
51 option.
52
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53config CONSOLE_LOGLEVEL_QUIET
54 int "quiet console loglevel (1-15)"
55 range 1 15
56 default "4"
57 help
58 loglevel to use when "quiet" is passed on the kernel commandline.
59
60 When "quiet" is passed on the kernel commandline this loglevel
61 will be used as the loglevel. IOW passing "quiet" will be the
62 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
63
42a9dc0b 64config MESSAGE_LOGLEVEL_DEFAULT
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65 int "Default message log level (1-7)"
66 range 1 7
67 default "4"
68 help
69 Default log level for printk statements with no specified priority.
70
71 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
72 that are auditing their logs closely may want to set it to a lower
73 priority.
74
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75 Note: This does not affect what message level gets printed on the console
76 by default. To change that, use loglevel=<x> in the kernel bootargs,
77 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
78
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79config BOOT_PRINTK_DELAY
80 bool "Delay each boot printk message by N milliseconds"
81 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
82 help
83 This build option allows you to read kernel boot messages
84 by inserting a short delay after each one. The delay is
85 specified in milliseconds on the kernel command line,
86 using "boot_delay=N".
87
88 It is likely that you would also need to use "lpj=M" to preset
89 the "loops per jiffie" value.
90 See a previous boot log for the "lpj" value to use for your
91 system, and then set "lpj=M" before setting "boot_delay=N".
92 NOTE: Using this option may adversely affect SMP systems.
93 I.e., processors other than the first one may not boot up.
94 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
95 what it believes to be lockup conditions.
96
97config DYNAMIC_DEBUG
98 bool "Enable dynamic printk() support"
99 default n
100 depends on PRINTK
101 depends on DEBUG_FS
102 help
103
104 Compiles debug level messages into the kernel, which would not
105 otherwise be available at runtime. These messages can then be
106 enabled/disabled based on various levels of scope - per source file,
107 function, module, format string, and line number. This mechanism
108 implicitly compiles in all pr_debug() and dev_dbg() calls, which
109 enlarges the kernel text size by about 2%.
110
111 If a source file is compiled with DEBUG flag set, any
112 pr_debug() calls in it are enabled by default, but can be
113 disabled at runtime as below. Note that DEBUG flag is
114 turned on by many CONFIG_*DEBUG* options.
115
116 Usage:
117
118 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
119 which is contained in the 'debugfs' filesystem. Thus, the debugfs
120 filesystem must first be mounted before making use of this feature.
121 We refer the control file as: <debugfs>/dynamic_debug/control. This
122 file contains a list of the debug statements that can be enabled. The
123 format for each line of the file is:
124
125 filename:lineno [module]function flags format
126
127 filename : source file of the debug statement
128 lineno : line number of the debug statement
129 module : module that contains the debug statement
130 function : function that contains the debug statement
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131 flags : '=p' means the line is turned 'on' for printing
132 format : the format used for the debug statement
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133
134 From a live system:
135
136 nullarbor:~ # cat <debugfs>/dynamic_debug/control
137 # filename:lineno [module]function flags format
138 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
139 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
140 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
141
142 Example usage:
143
144 // enable the message at line 1603 of file svcsock.c
145 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
146 <debugfs>/dynamic_debug/control
147
148 // enable all the messages in file svcsock.c
149 nullarbor:~ # echo -n 'file svcsock.c +p' >
150 <debugfs>/dynamic_debug/control
151
152 // enable all the messages in the NFS server module
153 nullarbor:~ # echo -n 'module nfsd +p' >
154 <debugfs>/dynamic_debug/control
155
156 // enable all 12 messages in the function svc_process()
157 nullarbor:~ # echo -n 'func svc_process +p' >
158 <debugfs>/dynamic_debug/control
159
160 // disable all 12 messages in the function svc_process()
161 nullarbor:~ # echo -n 'func svc_process -p' >
162 <debugfs>/dynamic_debug/control
163
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164 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
165 information.
604ff0dc 166
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167config SYMBOLIC_ERRNAME
168 bool "Support symbolic error names in printf"
169 default y if PRINTK
170 help
171 If you say Y here, the kernel's printf implementation will
172 be able to print symbolic error names such as ENOSPC instead
173 of the number 28. It makes the kernel image slightly larger
174 (about 3KB), but can make the kernel logs easier to read.
175
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176config DEBUG_BUGVERBOSE
177 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
178 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
179 default y
180 help
181 Say Y here to make BUG() panics output the file name and line number
182 of the BUG call as well as the EIP and oops trace. This aids
183 debugging but costs about 70-100K of memory.
184
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185endmenu # "printk and dmesg options"
186
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187menu "Compile-time checks and compiler options"
188
189config DEBUG_INFO
190 bool "Compile the kernel with debug info"
12b13835 191 depends on DEBUG_KERNEL && !COMPILE_TEST
6dfc0665 192 help
68d4b3df 193 If you say Y here the resulting kernel image will include
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194 debugging info resulting in a larger kernel image.
195 This adds debug symbols to the kernel and modules (gcc -g), and
196 is needed if you intend to use kernel crashdump or binary object
197 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
198 Say Y here only if you plan to debug the kernel.
199
200 If unsure, say N.
201
202config DEBUG_INFO_REDUCED
203 bool "Reduce debugging information"
204 depends on DEBUG_INFO
205 help
206 If you say Y here gcc is instructed to generate less debugging
207 information for structure types. This means that tools that
208 need full debugging information (like kgdb or systemtap) won't
209 be happy. But if you merely need debugging information to
210 resolve line numbers there is no loss. Advantage is that
211 build directory object sizes shrink dramatically over a full
212 DEBUG_INFO build and compile times are reduced too.
213 Only works with newer gcc versions.
214
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215config DEBUG_INFO_SPLIT
216 bool "Produce split debuginfo in .dwo files"
a687a533 217 depends on DEBUG_INFO
9d937444 218 depends on $(cc-option,-gsplit-dwarf)
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219 help
220 Generate debug info into separate .dwo files. This significantly
221 reduces the build directory size for builds with DEBUG_INFO,
222 because it stores the information only once on disk in .dwo
223 files instead of multiple times in object files and executables.
224 In addition the debug information is also compressed.
225
226 Requires recent gcc (4.7+) and recent gdb/binutils.
227 Any tool that packages or reads debug information would need
228 to know about the .dwo files and include them.
229 Incompatible with older versions of ccache.
230
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231config DEBUG_INFO_DWARF4
232 bool "Generate dwarf4 debuginfo"
233 depends on DEBUG_INFO
9d937444 234 depends on $(cc-option,-gdwarf-4)
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235 help
236 Generate dwarf4 debug info. This requires recent versions
237 of gcc and gdb. It makes the debug information larger.
238 But it significantly improves the success of resolving
239 variables in gdb on optimized code.
240
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241config DEBUG_INFO_BTF
242 bool "Generate BTF typeinfo"
243 depends on DEBUG_INFO
244 help
245 Generate deduplicated BTF type information from DWARF debug info.
246 Turning this on expects presence of pahole tool, which will convert
247 DWARF type info into equivalent deduplicated BTF type info.
248
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249config GDB_SCRIPTS
250 bool "Provide GDB scripts for kernel debugging"
251 depends on DEBUG_INFO
252 help
253 This creates the required links to GDB helper scripts in the
254 build directory. If you load vmlinux into gdb, the helper
255 scripts will be automatically imported by gdb as well, and
256 additional functions are available to analyze a Linux kernel
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257 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
258 for further details.
3ee7b3fa 259
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260config ENABLE_MUST_CHECK
261 bool "Enable __must_check logic"
262 default y
263 help
264 Enable the __must_check logic in the kernel build. Disable this to
265 suppress the "warning: ignoring return value of 'foo', declared with
266 attribute warn_unused_result" messages.
1da177e4 267
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268config FRAME_WARN
269 int "Warn for stack frames larger than (needs gcc 4.4)"
270 range 0 8192
0e07f663 271 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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272 default 1280 if (!64BIT && PARISC)
273 default 1024 if (!64BIT && !PARISC)
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274 default 2048 if 64BIT
275 help
276 Tell gcc to warn at build time for stack frames larger than this.
277 Setting this too low will cause a lot of warnings.
278 Setting it to 0 disables the warning.
279 Requires gcc 4.4
280
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281config STRIP_ASM_SYMS
282 bool "Strip assembler-generated symbols during link"
283 default n
284 help
285 Strip internal assembler-generated symbols during a link (symbols
286 that look like '.Lxxx') so they don't pollute the output of
287 get_wchan() and suchlike.
288
1873e870 289config READABLE_ASM
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290 bool "Generate readable assembler code"
291 depends on DEBUG_KERNEL
bf4735a4 292 help
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293 Disable some compiler optimizations that tend to generate human unreadable
294 assembler output. This may make the kernel slightly slower, but it helps
295 to keep kernel developers who have to stare a lot at assembler listings
296 sane.
bf4735a4 297
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298config HEADERS_INSTALL
299 bool "Install uapi headers to usr/include"
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300 depends on !UML
301 help
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302 This option will install uapi headers (headers exported to user-space)
303 into the usr/include directory for use during the kernel build.
304 This is unneeded for building the kernel itself, but needed for some
305 user-space program samples. It is also needed by some features such
306 as uapi header sanity checks.
307
9012d011 308config OPTIMIZE_INLINING
ac7c3e4f 309 def_bool y
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310 help
311 This option determines if the kernel forces gcc to inline the functions
312 developers have marked 'inline'. Doing so takes away freedom from gcc to
313 do what it thinks is best, which is desirable for the gcc 3.x series of
314 compilers. The gcc 4.x series have a rewritten inlining algorithm and
315 enabling this option will generate a smaller kernel there. Hopefully
316 this algorithm is so good that allowing gcc 4.x and above to make the
317 decision will become the default in the future. Until then this option
318 is there to test gcc for this.
319
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320config DEBUG_SECTION_MISMATCH
321 bool "Enable full Section mismatch analysis"
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322 help
323 The section mismatch analysis checks if there are illegal
324 references from one section to another section.
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325 During linktime or runtime, some sections are dropped;
326 any use of code/data previously in these sections would
91341d4b 327 most likely result in an oops.
e809ab01 328 In the code, functions and variables are annotated with
0db0628d 329 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 330 which results in the code/data being placed in specific sections.
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331 The section mismatch analysis is always performed after a full
332 kernel build, and enabling this option causes the following
b7dca6dd 333 additional step to occur:
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334 - Add the option -fno-inline-functions-called-once to gcc commands.
335 When inlining a function annotated with __init in a non-init
336 function, we would lose the section information and thus
91341d4b 337 the analysis would not catch the illegal reference.
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338 This option tells gcc to inline less (but it does result in
339 a larger kernel).
91341d4b 340
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341config SECTION_MISMATCH_WARN_ONLY
342 bool "Make section mismatch errors non-fatal"
343 default y
344 help
345 If you say N here, the build process will fail if there are any
346 section mismatch, instead of just throwing warnings.
347
348 If unsure, say Y.
349
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350#
351# Select this config option from the architecture Kconfig, if it
352# is preferred to always offer frame pointers as a config
353# option on the architecture (regardless of KERNEL_DEBUG):
354#
355config ARCH_WANT_FRAME_POINTERS
356 bool
f346f4b3 357
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358config FRAME_POINTER
359 bool "Compile the kernel with frame pointers"
a687a533 360 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 361 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 362 help
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363 If you say Y here the resulting kernel image will be slightly
364 larger and slower, but it gives very useful debugging information
365 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 366
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367config STACK_VALIDATION
368 bool "Compile-time stack metadata validation"
369 depends on HAVE_STACK_VALIDATION
370 default n
371 help
372 Add compile-time checks to validate stack metadata, including frame
373 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
374 that runtime stack traces are more reliable.
375
ee9f8fce 376 This is also a prerequisite for generation of ORC unwind data, which
11af8474 377 is needed for CONFIG_UNWINDER_ORC.
ee9f8fce 378
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379 For more information, see
380 tools/objtool/Documentation/stack-validation.txt.
381
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382config DEBUG_FORCE_WEAK_PER_CPU
383 bool "Force weak per-cpu definitions"
384 depends on DEBUG_KERNEL
8446f1d3 385 help
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386 s390 and alpha require percpu variables in modules to be
387 defined weak to work around addressing range issue which
388 puts the following two restrictions on percpu variable
389 definitions.
8446f1d3 390
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391 1. percpu symbols must be unique whether static or not
392 2. percpu variables can't be defined inside a function
8446f1d3 393
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394 To ensure that generic code follows the above rules, this
395 option forces all percpu variables to be defined as weak.
5f329089 396
6dfc0665 397endmenu # "Compiler options"
8446f1d3 398
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399menu "Generic Kernel Debugging Instruments"
400
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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
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412 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
413 Don't say Y unless you really know what this hack does.
8446f1d3 414
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415config 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
f8998c22 422 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 423
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424config 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
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434config DEBUG_FS
435 bool "Debug Filesystem"
436 help
437 debugfs is a virtual file system that kernel developers use to put
438 debugging files into. Enable this option to be able to read and
439 write to these files.
440
441 For detailed documentation on the debugfs API, see
442 Documentation/filesystems/.
443
444 If unsure, say N.
445
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446source "lib/Kconfig.kgdb"
447
448source "lib/Kconfig.ubsan"
449
450endmenu
451
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452config DEBUG_KERNEL
453 bool "Kernel debugging"
fef2c9bc 454 help
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455 Say Y here if you are developing drivers or trying to debug and
456 identify kernel problems.
fef2c9bc 457
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458config DEBUG_MISC
459 bool "Miscellaneous debug code"
460 default DEBUG_KERNEL
461 depends on DEBUG_KERNEL
462 help
463 Say Y here if you need to enable miscellaneous debug code that should
464 be under a more specific debug option but isn't.
465
466
0610c8a8 467menu "Memory Debugging"
fef2c9bc 468
8636a1f9 469source "mm/Kconfig.debug"
fef2c9bc 470
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471config DEBUG_OBJECTS
472 bool "Debug object operations"
473 depends on DEBUG_KERNEL
9c44bc03 474 help
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475 If you say Y here, additional code will be inserted into the
476 kernel to track the life time of various objects and validate
477 the operations on those objects.
9c44bc03 478
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479config DEBUG_OBJECTS_SELFTEST
480 bool "Debug objects selftest"
481 depends on DEBUG_OBJECTS
482 help
483 This enables the selftest of the object debug code.
9c44bc03 484
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485config DEBUG_OBJECTS_FREE
486 bool "Debug objects in freed memory"
487 depends on DEBUG_OBJECTS
488 help
489 This enables checks whether a k/v free operation frees an area
490 which contains an object which has not been deactivated
491 properly. This can make kmalloc/kfree-intensive workloads
492 much slower.
3ac7fe5a 493
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494config DEBUG_OBJECTS_TIMERS
495 bool "Debug timer objects"
496 depends on DEBUG_OBJECTS
497 help
498 If you say Y here, additional code will be inserted into the
499 timer routines to track the life time of timer objects and
500 validate the timer operations.
501
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502config DEBUG_OBJECTS_WORK
503 bool "Debug work objects"
504 depends on DEBUG_OBJECTS
505 help
506 If you say Y here, additional code will be inserted into the
507 work queue routines to track the life time of work objects and
508 validate the work operations.
509
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510config DEBUG_OBJECTS_RCU_HEAD
511 bool "Debug RCU callbacks objects"
fc2ecf7e 512 depends on DEBUG_OBJECTS
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513 help
514 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
515
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516config DEBUG_OBJECTS_PERCPU_COUNTER
517 bool "Debug percpu counter objects"
518 depends on DEBUG_OBJECTS
519 help
520 If you say Y here, additional code will be inserted into the
521 percpu counter routines to track the life time of percpu counter
522 objects and validate the percpu counter operations.
523
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524config DEBUG_OBJECTS_ENABLE_DEFAULT
525 int "debug_objects bootup default value (0-1)"
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526 range 0 1
527 default "1"
528 depends on DEBUG_OBJECTS
529 help
530 Debug objects boot parameter default value
3ae70205 531
1da177e4 532config DEBUG_SLAB
4a2f0acf 533 bool "Debug slab memory allocations"
4675ff05 534 depends on DEBUG_KERNEL && SLAB
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535 help
536 Say Y here to have the kernel do limited verification on memory
537 allocation as well as poisoning memory on free to catch use of freed
538 memory. This can make kmalloc/kfree-intensive workloads much slower.
539
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540config SLUB_DEBUG_ON
541 bool "SLUB debugging on by default"
4675ff05 542 depends on SLUB && SLUB_DEBUG
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543 default n
544 help
545 Boot with debugging on by default. SLUB boots by default with
546 the runtime debug capabilities switched off. Enabling this is
547 equivalent to specifying the "slub_debug" parameter on boot.
548 There is no support for more fine grained debug control like
549 possible with slub_debug=xxx. SLUB debugging may be switched
550 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
551 "slub_debug=-".
552
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553config SLUB_STATS
554 default n
555 bool "Enable SLUB performance statistics"
ab4d5ed5 556 depends on SLUB && SYSFS
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557 help
558 SLUB statistics are useful to debug SLUBs allocation behavior in
559 order find ways to optimize the allocator. This should never be
560 enabled for production use since keeping statistics slows down
561 the allocator by a few percentage points. The slabinfo command
562 supports the determination of the most active slabs to figure
563 out which slabs are relevant to a particular load.
564 Try running: slabinfo -DA
565
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566config HAVE_DEBUG_KMEMLEAK
567 bool
568
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569config DEBUG_KMEMLEAK
570 bool "Kernel memory leak detector"
525c1f92 571 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 572 select DEBUG_FS
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573 select STACKTRACE if STACKTRACE_SUPPORT
574 select KALLSYMS
b60e26a2 575 select CRC32
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576 help
577 Say Y here if you want to enable the memory leak
578 detector. The memory allocation/freeing is traced in a way
579 similar to the Boehm's conservative garbage collector, the
580 difference being that the orphan objects are not freed but
581 only shown in /sys/kernel/debug/kmemleak. Enabling this
582 feature will introduce an overhead to memory
700199b0 583 allocations. See Documentation/dev-tools/kmemleak.rst for more
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584 details.
585
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586 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
587 of finding leaks due to the slab objects poisoning.
588
589 In order to access the kmemleak file, debugfs needs to be
590 mounted (usually at /sys/kernel/debug).
591
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592config DEBUG_KMEMLEAK_MEM_POOL_SIZE
593 int "Kmemleak memory pool size"
0610c8a8 594 depends on DEBUG_KMEMLEAK
c59180ae 595 range 200 1000000
b751c52b 596 default 16000
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597 help
598 Kmemleak must track all the memory allocations to avoid
599 reporting false positives. Since memory may be allocated or
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600 freed before kmemleak is fully initialised, use a static pool
601 of metadata objects to track such callbacks. After kmemleak is
602 fully initialised, this memory pool acts as an emergency one
603 if slab allocations fail.
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604
605config DEBUG_KMEMLEAK_TEST
606 tristate "Simple test for the kernel memory leak detector"
607 depends on DEBUG_KMEMLEAK && m
608 help
609 This option enables a module that explicitly leaks memory.
610
611 If unsure, say N.
612
613config DEBUG_KMEMLEAK_DEFAULT_OFF
614 bool "Default kmemleak to off"
615 depends on DEBUG_KMEMLEAK
616 help
617 Say Y here to disable kmemleak by default. It can then be enabled
618 on the command line via kmemleak=on.
619
d53ce042
SK
620config DEBUG_KMEMLEAK_AUTO_SCAN
621 bool "Enable kmemleak auto scan thread on boot up"
622 default y
623 depends on DEBUG_KMEMLEAK
624 help
625 Depending on the cpu, kmemleak scan may be cpu intensive and can
626 stall user tasks at times. This option enables/disables automatic
627 kmemleak scan at boot up.
628
629 Say N here to disable kmemleak auto scan thread to stop automatic
630 scanning. Disabling this option disables automatic reporting of
631 memory leaks.
632
633 If unsure, say Y.
634
0610c8a8
DH
635config DEBUG_STACK_USAGE
636 bool "Stack utilization instrumentation"
6c31da34 637 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
638 help
639 Enables the display of the minimum amount of free stack which each
640 task has ever had available in the sysrq-T and sysrq-P debug output.
641
642 This option will slow down process creation somewhat.
643
dc9b9638
CD
644config SCHED_STACK_END_CHECK
645 bool "Detect stack corruption on calls to schedule()"
646 depends on DEBUG_KERNEL
647 default n
648 help
649 This option checks for a stack overrun on calls to schedule().
650 If the stack end location is found to be over written always panic as
651 the content of the corrupted region can no longer be trusted.
652 This is to ensure no erroneous behaviour occurs which could result in
653 data corruption or a sporadic crash at a later stage once the region
654 is examined. The runtime overhead introduced is minimal.
655
0610c8a8
DH
656config DEBUG_VM
657 bool "Debug VM"
658 depends on DEBUG_KERNEL
659 help
660 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 661 that may impact performance.
0610c8a8
DH
662
663 If unsure, say N.
664
4f115147
DB
665config DEBUG_VM_VMACACHE
666 bool "Debug VMA caching"
667 depends on DEBUG_VM
668 help
669 Enable this to turn on VMA caching debug information. Doing so
670 can cause significant overhead, so only enable it in non-production
671 environments.
672
673 If unsure, say N.
674
0610c8a8
DH
675config DEBUG_VM_RB
676 bool "Debug VM red-black trees"
677 depends on DEBUG_VM
678 help
a663dad6 679 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
680
681 If unsure, say N.
682
95ad9755
KS
683config DEBUG_VM_PGFLAGS
684 bool "Debug page-flags operations"
685 depends on DEBUG_VM
686 help
687 Enables extra validation on page flags operations.
688
689 If unsure, say N.
690
fa5b6ec9
LA
691config ARCH_HAS_DEBUG_VIRTUAL
692 bool
693
0610c8a8
DH
694config DEBUG_VIRTUAL
695 bool "Debug VM translations"
fa5b6ec9 696 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
697 help
698 Enable some costly sanity checks in virtual to page code. This can
699 catch mistakes with virt_to_page() and friends.
700
701 If unsure, say N.
702
703config DEBUG_NOMMU_REGIONS
704 bool "Debug the global anon/private NOMMU mapping region tree"
705 depends on DEBUG_KERNEL && !MMU
706 help
707 This option causes the global tree of anonymous and private mapping
708 regions to be regularly checked for invalid topology.
709
710config DEBUG_MEMORY_INIT
711 bool "Debug memory initialisation" if EXPERT
712 default !EXPERT
713 help
714 Enable this for additional checks during memory initialisation.
715 The sanity checks verify aspects of the VM such as the memory model
716 and other information provided by the architecture. Verbose
717 information will be printed at KERN_DEBUG loglevel depending
718 on the mminit_loglevel= command-line option.
719
720 If unsure, say Y
721
722config MEMORY_NOTIFIER_ERROR_INJECT
723 tristate "Memory hotplug notifier error injection module"
724 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
725 help
726 This option provides the ability to inject artificial errors to
727 memory hotplug notifier chain callbacks. It is controlled through
728 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
729
730 If the notifier call chain should be failed with some events
731 notified, write the error code to "actions/<notifier event>/error".
732
733 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
734
735 # cd /sys/kernel/debug/notifier-error-inject/memory
736 # echo -12 > actions/MEM_GOING_OFFLINE/error
737 # echo offline > /sys/devices/system/memory/memoryXXX/state
738 bash: echo: write error: Cannot allocate memory
739
740 To compile this code as a module, choose M here: the module will
741 be called memory-notifier-error-inject.
742
743 If unsure, say N.
744
745config DEBUG_PER_CPU_MAPS
746 bool "Debug access to per_cpu maps"
747 depends on DEBUG_KERNEL
748 depends on SMP
749 help
750 Say Y to verify that the per_cpu map being accessed has
751 been set up. This adds a fair amount of code to kernel memory
752 and decreases performance.
753
754 Say N if unsure.
755
756config DEBUG_HIGHMEM
757 bool "Highmem debugging"
758 depends on DEBUG_KERNEL && HIGHMEM
759 help
b1357c9f
GU
760 This option enables additional error checking for high memory
761 systems. Disable for production systems.
0610c8a8
DH
762
763config HAVE_DEBUG_STACKOVERFLOW
764 bool
765
766config DEBUG_STACKOVERFLOW
767 bool "Check for stack overflows"
768 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
769 ---help---
770 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 771 and exception stacks (if your architecture uses them). This
0610c8a8
DH
772 option will show detailed messages if free stack space drops
773 below a certain limit.
774
775 These kinds of bugs usually occur when call-chains in the
776 kernel get too deep, especially when interrupts are
777 involved.
778
779 Use this in cases where you see apparently random memory
780 corruption, especially if it appears in 'struct thread_info'
781
782 If in doubt, say "N".
783
0b24becc
AR
784source "lib/Kconfig.kasan"
785
0610c8a8
DH
786endmenu # "Memory Debugging"
787
a304e1b8
DW
788config DEBUG_SHIRQ
789 bool "Debug shared IRQ handlers"
0244ad00 790 depends on DEBUG_KERNEL
a304e1b8
DW
791 help
792 Enable this to generate a spurious interrupt as soon as a shared
793 interrupt handler is registered, and just before one is deregistered.
794 Drivers ought to be able to handle interrupts coming in at those
795 points; some don't and need to be caught.
796
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CD
797menu "Debug Oops, Lockups and Hangs"
798
799config PANIC_ON_OOPS
800 bool "Panic on Oops"
801 help
802 Say Y here to enable the kernel to panic when it oopses. This
803 has the same effect as setting oops=panic on the kernel command
804 line.
805
806 This feature is useful to ensure that the kernel does not do
807 anything erroneous after an oops which could result in data
808 corruption or other issues.
809
810 Say N if unsure.
811
812config PANIC_ON_OOPS_VALUE
813 int
814 range 0 1
815 default 0 if !PANIC_ON_OOPS
816 default 1 if PANIC_ON_OOPS
817
818config PANIC_TIMEOUT
819 int "panic timeout"
820 default 0
821 help
822 Set the timeout value (in seconds) until a reboot occurs when the
823 the kernel panics. If n = 0, then we wait forever. A timeout
824 value n > 0 will wait n seconds before rebooting, while a timeout
825 value n < 0 will reboot immediately.
92aef8fb 826
58687acb 827config LOCKUP_DETECTOR
05a4a952
NP
828 bool
829
830config SOFTLOCKUP_DETECTOR
831 bool "Detect Soft Lockups"
dea20a3f 832 depends on DEBUG_KERNEL && !S390
05a4a952 833 select LOCKUP_DETECTOR
8446f1d3 834 help
58687acb 835 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 836 soft lockups.
58687acb
DZ
837
838 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 839 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
840 chance to run. The current stack trace is displayed upon
841 detection and the system will stay locked up.
8446f1d3 842
5f00ae0d
RD
843config BOOTPARAM_SOFTLOCKUP_PANIC
844 bool "Panic (Reboot) On Soft Lockups"
845 depends on SOFTLOCKUP_DETECTOR
846 help
847 Say Y here to enable the kernel to panic on "soft lockups",
848 which are bugs that cause the kernel to loop in kernel
849 mode for more than 20 seconds (configurable using the watchdog_thresh
850 sysctl), without giving other tasks a chance to run.
851
852 The panic can be used in combination with panic_timeout,
853 to cause the system to reboot automatically after a
854 lockup has been detected. This feature is useful for
855 high-availability systems that have uptime guarantees and
856 where a lockup must be resolved ASAP.
857
858 Say N if unsure.
859
860config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
861 int
862 depends on SOFTLOCKUP_DETECTOR
863 range 0 1
864 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
865 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
866
05a4a952
NP
867config HARDLOCKUP_DETECTOR_PERF
868 bool
869 select SOFTLOCKUP_DETECTOR
870
7edaeb68
TG
871#
872# Enables a timestamp based low pass filter to compensate for perf based
873# hard lockup detection which runs too fast due to turbo modes.
874#
875config HARDLOCKUP_CHECK_TIMESTAMP
876 bool
877
05a4a952
NP
878#
879# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
880# lockup detector rather than the perf based detector.
881#
882config HARDLOCKUP_DETECTOR
883 bool "Detect Hard Lockups"
884 depends on DEBUG_KERNEL && !S390
885 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
886 select LOCKUP_DETECTOR
887 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
888 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
889 help
890 Say Y here to enable the kernel to act as a watchdog to detect
891 hard lockups.
892
58687acb 893 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 894 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
895 chance to run. The current stack trace is displayed upon detection
896 and the system will stay locked up.
8446f1d3 897
fef2c9bc
DZ
898config BOOTPARAM_HARDLOCKUP_PANIC
899 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 900 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
901 help
902 Say Y here to enable the kernel to panic on "hard lockups",
903 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
904 mode with interrupts disabled for more than 10 seconds (configurable
905 using the watchdog_thresh sysctl).
fef2c9bc
DZ
906
907 Say N if unsure.
908
909config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
910 int
8f1f66ed 911 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
912 range 0 1
913 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
914 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
915
e162b39a
MSB
916config DETECT_HUNG_TASK
917 bool "Detect Hung Tasks"
918 depends on DEBUG_KERNEL
05a4a952 919 default SOFTLOCKUP_DETECTOR
e162b39a 920 help
0610c8a8
DH
921 Say Y here to enable the kernel to detect "hung tasks",
922 which are bugs that cause the task to be stuck in
96b03ab8 923 uninterruptible "D" state indefinitely.
1da177e4 924
0610c8a8
DH
925 When a hung task is detected, the kernel will print the
926 current stack trace (which you should report), but the
927 task will stay in uninterruptible state. If lockdep is
928 enabled then all held locks will also be reported. This
929 feature has negligible overhead.
871751e2 930
0610c8a8
DH
931config DEFAULT_HUNG_TASK_TIMEOUT
932 int "Default timeout for hung task detection (in seconds)"
933 depends on DETECT_HUNG_TASK
934 default 120
f0630fff 935 help
0610c8a8
DH
936 This option controls the default timeout (in seconds) used
937 to determine when a task has become non-responsive and should
938 be considered hung.
f0630fff 939
0610c8a8
DH
940 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
941 sysctl or by writing a value to
942 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 943
0610c8a8
DH
944 A timeout of 0 disables the check. The default is two minutes.
945 Keeping the default should be fine in most cases.
b69ec42b 946
0610c8a8
DH
947config BOOTPARAM_HUNG_TASK_PANIC
948 bool "Panic (Reboot) On Hung Tasks"
949 depends on DETECT_HUNG_TASK
3bba00d7 950 help
0610c8a8
DH
951 Say Y here to enable the kernel to panic on "hung tasks",
952 which are bugs that cause the kernel to leave a task stuck
953 in uninterruptible "D" state.
3bba00d7 954
0610c8a8
DH
955 The panic can be used in combination with panic_timeout,
956 to cause the system to reboot automatically after a
957 hung task has been detected. This feature is useful for
958 high-availability systems that have uptime guarantees and
959 where a hung tasks must be resolved ASAP.
bf96d1e3 960
0610c8a8 961 Say N if unsure.
bf96d1e3 962
0610c8a8
DH
963config BOOTPARAM_HUNG_TASK_PANIC_VALUE
964 int
965 depends on DETECT_HUNG_TASK
966 range 0 1
967 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
968 default 1 if BOOTPARAM_HUNG_TASK_PANIC
3bba00d7 969
82607adc
TH
970config WQ_WATCHDOG
971 bool "Detect Workqueue Stalls"
972 depends on DEBUG_KERNEL
973 help
974 Say Y here to enable stall detection on workqueues. If a
975 worker pool doesn't make forward progress on a pending work
976 item for over a given amount of time, 30s by default, a
977 warning message is printed along with dump of workqueue
978 state. This can be configured through kernel parameter
979 "workqueue.watchdog_thresh" and its sysfs counterpart.
980
92aef8fb
DH
981endmenu # "Debug lockups and hangs"
982
ebebdd09 983menu "Scheduler Debugging"
5800dc3c 984
0610c8a8
DH
985config SCHED_DEBUG
986 bool "Collect scheduler debugging info"
987 depends on DEBUG_KERNEL && PROC_FS
988 default y
0822ee4a 989 help
0610c8a8
DH
990 If you say Y here, the /proc/sched_debug file will be provided
991 that can help debug the scheduler. The runtime overhead of this
992 option is minimal.
0822ee4a 993
f6db8347
NR
994config SCHED_INFO
995 bool
996 default n
997
0610c8a8
DH
998config SCHEDSTATS
999 bool "Collect scheduler statistics"
1000 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1001 select SCHED_INFO
0610c8a8
DH
1002 help
1003 If you say Y here, additional code will be inserted into the
1004 scheduler and related routines to collect statistics about
1005 scheduler behavior and provide them in /proc/schedstat. These
1006 stats may be useful for both tuning and debugging the scheduler
1007 If you aren't debugging the scheduler or trying to tune a specific
1008 application, you can say N to avoid the very slight overhead
1009 this adds.
0822ee4a 1010
ebebdd09 1011endmenu
0d9e2632 1012
3c17ad19
JS
1013config DEBUG_TIMEKEEPING
1014 bool "Enable extra timekeeping sanity checking"
1015 help
1016 This option will enable additional timekeeping sanity checks
1017 which may be helpful when diagnosing issues where timekeeping
1018 problems are suspected.
1019
1020 This may include checks in the timekeeping hotpaths, so this
1021 option may have a (very small) performance impact to some
1022 workloads.
1023
1024 If unsure, say N.
1025
1da177e4
LT
1026config DEBUG_PREEMPT
1027 bool "Debug preemptible kernel"
9f472869 1028 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1029 default y
1030 help
1031 If you say Y here then the kernel will use a debug variant of the
1032 commonly used smp_processor_id() function and will print warnings
1033 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1034 will detect preemption count underflows.
1035
9eade16b
DH
1036menu "Lock Debugging (spinlocks, mutexes, etc...)"
1037
f07cbebb
WL
1038config LOCK_DEBUGGING_SUPPORT
1039 bool
1040 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1041 default y
1042
19193bca
WL
1043config PROVE_LOCKING
1044 bool "Lock debugging: prove locking correctness"
1045 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1046 select LOCKDEP
1047 select DEBUG_SPINLOCK
1048 select DEBUG_MUTEXES
1049 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1050 select DEBUG_RWSEMS
19193bca
WL
1051 select DEBUG_WW_MUTEX_SLOWPATH
1052 select DEBUG_LOCK_ALLOC
1053 select TRACE_IRQFLAGS
1054 default n
1055 help
1056 This feature enables the kernel to prove that all locking
1057 that occurs in the kernel runtime is mathematically
1058 correct: that under no circumstance could an arbitrary (and
1059 not yet triggered) combination of observed locking
1060 sequences (on an arbitrary number of CPUs, running an
1061 arbitrary number of tasks and interrupt contexts) cause a
1062 deadlock.
1063
1064 In short, this feature enables the kernel to report locking
1065 related deadlocks before they actually occur.
1066
1067 The proof does not depend on how hard and complex a
1068 deadlock scenario would be to trigger: how many
1069 participant CPUs, tasks and irq-contexts would be needed
1070 for it to trigger. The proof also does not depend on
1071 timing: if a race and a resulting deadlock is possible
1072 theoretically (no matter how unlikely the race scenario
1073 is), it will be proven so and will immediately be
1074 reported by the kernel (once the event is observed that
1075 makes the deadlock theoretically possible).
1076
1077 If a deadlock is impossible (i.e. the locking rules, as
1078 observed by the kernel, are mathematically correct), the
1079 kernel reports nothing.
1080
1081 NOTE: this feature can also be enabled for rwlocks, mutexes
1082 and rwsems - in which case all dependencies between these
1083 different locking variants are observed and mapped too, and
1084 the proof of observed correctness is also maintained for an
1085 arbitrary combination of these separate locking variants.
1086
387b1468 1087 For more details, see Documentation/locking/lockdep-design.rst.
19193bca
WL
1088
1089config LOCK_STAT
1090 bool "Lock usage statistics"
1091 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1092 select LOCKDEP
1093 select DEBUG_SPINLOCK
1094 select DEBUG_MUTEXES
1095 select DEBUG_RT_MUTEXES if RT_MUTEXES
1096 select DEBUG_LOCK_ALLOC
1097 default n
1098 help
1099 This feature enables tracking lock contention points
1100
387b1468 1101 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1102
1103 This also enables lock events required by "perf lock",
1104 subcommand of perf.
1105 If you want to use "perf lock", you also need to turn on
1106 CONFIG_EVENT_TRACING.
1107
1108 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1109 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1110
e7eebaf6
IM
1111config DEBUG_RT_MUTEXES
1112 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1113 depends on DEBUG_KERNEL && RT_MUTEXES
1114 help
1115 This allows rt mutex semantics violations and rt mutex related
1116 deadlocks (lockups) to be detected and reported automatically.
1117
1da177e4 1118config DEBUG_SPINLOCK
4d9f34ad 1119 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1120 depends on DEBUG_KERNEL
e335e3eb 1121 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1122 help
1123 Say Y here and build SMP to catch missing spinlock initialization
1124 and certain other kinds of spinlock errors commonly made. This is
1125 best used in conjunction with the NMI watchdog so that spinlock
1126 deadlocks are also debuggable.
1127
4d9f34ad
IM
1128config DEBUG_MUTEXES
1129 bool "Mutex debugging: basic checks"
1130 depends on DEBUG_KERNEL
1131 help
1132 This feature allows mutex semantics violations to be detected and
1133 reported.
1134
23010027
DV
1135config DEBUG_WW_MUTEX_SLOWPATH
1136 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1137 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1138 select DEBUG_LOCK_ALLOC
1139 select DEBUG_SPINLOCK
1140 select DEBUG_MUTEXES
1141 help
1142 This feature enables slowpath testing for w/w mutex users by
1143 injecting additional -EDEADLK wound/backoff cases. Together with
1144 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1145 will test all possible w/w mutex interface abuse with the
1146 exception of simply not acquiring all the required locks.
4d692373
RC
1147 Note that this feature can introduce significant overhead, so
1148 it really should not be enabled in a production or distro kernel,
1149 even a debug kernel. If you are a driver writer, enable it. If
1150 you are a distro, do not.
23010027 1151
5149cbac
WL
1152config DEBUG_RWSEMS
1153 bool "RW Semaphore debugging: basic checks"
c71fd893 1154 depends on DEBUG_KERNEL
5149cbac 1155 help
c71fd893
WL
1156 This debugging feature allows mismatched rw semaphore locks
1157 and unlocks to be detected and reported.
5149cbac 1158
4d9f34ad
IM
1159config DEBUG_LOCK_ALLOC
1160 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1161 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad
IM
1162 select DEBUG_SPINLOCK
1163 select DEBUG_MUTEXES
f5694788 1164 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1165 select LOCKDEP
1166 help
1167 This feature will check whether any held lock (spinlock, rwlock,
1168 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1169 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1170 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1171 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1172 held during task exit.
1173
4d9f34ad
IM
1174config LOCKDEP
1175 bool
f07cbebb 1176 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1177 select STACKTRACE
f9b58e8c 1178 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
4d9f34ad
IM
1179 select KALLSYMS
1180 select KALLSYMS_ALL
1181
395102db
DJ
1182config LOCKDEP_SMALL
1183 bool
1184
4d9f34ad
IM
1185config DEBUG_LOCKDEP
1186 bool "Lock dependency engine debugging"
517e7aa5 1187 depends on DEBUG_KERNEL && LOCKDEP
4d9f34ad
IM
1188 help
1189 If you say Y here, the lock dependency engine will do
1190 additional runtime checks to debug itself, at the price
1191 of more runtime overhead.
1192
d902db1e
FW
1193config DEBUG_ATOMIC_SLEEP
1194 bool "Sleep inside atomic section checking"
e8f7c70f 1195 select PREEMPT_COUNT
1da177e4 1196 depends on DEBUG_KERNEL
87a4c375 1197 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1198 help
1199 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1200 noisy if they are called inside atomic sections: when a spinlock is
1201 held, inside an rcu read side critical section, inside preempt disabled
1202 sections, inside an interrupt, etc...
1da177e4 1203
cae2ed9a
IM
1204config DEBUG_LOCKING_API_SELFTESTS
1205 bool "Locking API boot-time self-tests"
1206 depends on DEBUG_KERNEL
1207 help
1208 Say Y here if you want the kernel to run a short self-test during
1209 bootup. The self-test checks whether common types of locking bugs
1210 are detected by debugging mechanisms or not. (if you disable
1211 lock debugging then those bugs wont be detected of course.)
1212 The following locking APIs are covered: spinlocks, rwlocks,
1213 mutexes and rwsems.
1214
0af3fe1e
PM
1215config LOCK_TORTURE_TEST
1216 tristate "torture tests for locking"
1217 depends on DEBUG_KERNEL
1218 select TORTURE_TEST
0af3fe1e
PM
1219 help
1220 This option provides a kernel module that runs torture tests
1221 on kernel locking primitives. The kernel module may be built
1222 after the fact on the running kernel to be tested, if desired.
1223
1224 Say Y here if you want kernel locking-primitive torture tests
1225 to be built into the kernel.
1226 Say M if you want these torture tests to build as a module.
1227 Say N if you are unsure.
1228
f2a5fec1
CW
1229config WW_MUTEX_SELFTEST
1230 tristate "Wait/wound mutex selftests"
1231 help
1232 This option provides a kernel module that runs tests on the
1233 on the struct ww_mutex locking API.
1234
1235 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1236 with this test harness.
1237
1238 Say M if you want these self tests to build as a module.
1239 Say N if you are unsure.
1240
9eade16b 1241endmenu # lock debugging
8637c099 1242
9eade16b
DH
1243config TRACE_IRQFLAGS
1244 bool
5ca43f6c 1245 help
9eade16b
DH
1246 Enables hooks to interrupt enabling and disabling for
1247 either tracing or lock debugging.
5ca43f6c 1248
8637c099 1249config STACKTRACE
0c38e1fe 1250 bool "Stack backtrace support"
8637c099 1251 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1252 help
1253 This option causes the kernel to create a /proc/pid/stack for
1254 every process, showing its current stack trace.
1255 It is also used by various kernel debugging features that require
1256 stack trace generation.
5ca43f6c 1257
eecabf56
TT
1258config WARN_ALL_UNSEEDED_RANDOM
1259 bool "Warn for all uses of unseeded randomness"
1260 default n
d06bfd19
JD
1261 help
1262 Some parts of the kernel contain bugs relating to their use of
1263 cryptographically secure random numbers before it's actually possible
1264 to generate those numbers securely. This setting ensures that these
1265 flaws don't go unnoticed, by enabling a message, should this ever
1266 occur. This will allow people with obscure setups to know when things
1267 are going wrong, so that they might contact developers about fixing
1268 it.
1269
eecabf56
TT
1270 Unfortunately, on some models of some architectures getting
1271 a fully seeded CRNG is extremely difficult, and so this can
1272 result in dmesg getting spammed for a surprisingly long
1273 time. This is really bad from a security perspective, and
1274 so architecture maintainers really need to do what they can
1275 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1276 However, since users cannot do anything actionable to
eecabf56
TT
1277 address this, by default the kernel will issue only a single
1278 warning for the first use of unseeded randomness.
1279
1280 Say Y here if you want to receive warnings for all uses of
1281 unseeded randomness. This will be of use primarily for
4c5d114e 1282 those developers interested in improving the security of
eecabf56
TT
1283 Linux kernels running on their architecture (or
1284 subarchitecture).
d06bfd19 1285
1da177e4
LT
1286config DEBUG_KOBJECT
1287 bool "kobject debugging"
1288 depends on DEBUG_KERNEL
1289 help
1290 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1291 to the syslog.
1da177e4 1292
c817a67e
RK
1293config DEBUG_KOBJECT_RELEASE
1294 bool "kobject release debugging"
2a999aa0 1295 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1296 help
1297 kobjects are reference counted objects. This means that their
1298 last reference count put is not predictable, and the kobject can
1299 live on past the point at which a driver decides to drop it's
1300 initial reference to the kobject gained on allocation. An
1301 example of this would be a struct device which has just been
1302 unregistered.
1303
1304 However, some buggy drivers assume that after such an operation,
1305 the memory backing the kobject can be immediately freed. This
1306 goes completely against the principles of a refcounted object.
1307
1308 If you say Y here, the kernel will delay the release of kobjects
1309 on the last reference count to improve the visibility of this
1310 kind of kobject release bug.
1311
9b2a60c4
CM
1312config HAVE_DEBUG_BUGVERBOSE
1313 bool
1314
3be5cbcd 1315menu "Debug kernel data structures"
1da177e4 1316
199a9afc
DJ
1317config DEBUG_LIST
1318 bool "Debug linked list manipulation"
4520bcb2 1319 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1320 help
1321 Enable this to turn on extended checks in the linked-list
1322 walking routines.
1323
1324 If unsure, say N.
1325
8e18faea 1326config DEBUG_PLIST
b8cfff68
DS
1327 bool "Debug priority linked list manipulation"
1328 depends on DEBUG_KERNEL
1329 help
1330 Enable this to turn on extended checks in the priority-ordered
1331 linked-list (plist) walking routines. This checks the entire
1332 list multiple times during each manipulation.
1333
1334 If unsure, say N.
1335
d6ec0842
JA
1336config DEBUG_SG
1337 bool "Debug SG table operations"
1338 depends on DEBUG_KERNEL
1339 help
1340 Enable this to turn on checks on scatter-gather tables. This can
1341 help find problems with drivers that do not properly initialize
1342 their sg tables.
1343
1344 If unsure, say N.
1345
1b2439db
AV
1346config DEBUG_NOTIFIERS
1347 bool "Debug notifier call chains"
1348 depends on DEBUG_KERNEL
1349 help
1350 Enable this to turn on sanity checking for notifier call chains.
1351 This is most useful for kernel developers to make sure that
1352 modules properly unregister themselves from notifier chains.
1353 This is a relatively cheap check but if you care about maximum
1354 performance, say N.
1355
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CD
1356config BUG_ON_DATA_CORRUPTION
1357 bool "Trigger a BUG when data corruption is detected"
1358 select DEBUG_LIST
1359 help
1360 Select this option if the kernel should BUG when it encounters
1361 data corruption in kernel memory structures when they get checked
1362 for validity.
1363
1364 If unsure, say N.
1365
1366endmenu
1367
e0e81739
DH
1368config DEBUG_CREDENTIALS
1369 bool "Debug credential management"
1370 depends on DEBUG_KERNEL
1371 help
1372 Enable this to turn on some debug checking for credential
1373 management. The additional code keeps track of the number of
1374 pointers from task_structs to any given cred struct, and checks to
1375 see that this number never exceeds the usage count of the cred
1376 struct.
1377
1378 Furthermore, if SELinux is enabled, this also checks that the
1379 security pointer in the cred struct is never seen to be invalid.
1380
1381 If unsure, say N.
1382
43a0a2a7 1383source "kernel/rcu/Kconfig.debug"
2f03e3ca 1384
f303fccb
TH
1385config DEBUG_WQ_FORCE_RR_CPU
1386 bool "Force round-robin CPU selection for unbound work items"
1387 depends on DEBUG_KERNEL
1388 default n
1389 help
1390 Workqueue used to implicitly guarantee that work items queued
1391 without explicit CPU specified are put on the local CPU. This
1392 guarantee is no longer true and while local CPU is still
1393 preferred work items may be put on foreign CPUs. Kernel
1394 parameter "workqueue.debug_force_rr_cpu" is added to force
1395 round-robin CPU selection to flush out usages which depend on the
1396 now broken guarantee. This config option enables the debug
1397 feature by default. When enabled, memory and cache locality will
1398 be impacted.
1399
870d6656 1400config DEBUG_BLOCK_EXT_DEVT
68d4b3df 1401 bool "Force extended block device numbers and spread them"
870d6656
TH
1402 depends on DEBUG_KERNEL
1403 depends on BLOCK
759f8ca3 1404 default n
870d6656 1405 help
0e11e342
TH
1406 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1407 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1408 YOU ARE DOING. Distros, please enable this and fix whatever
1409 is broken.
1410
870d6656
TH
1411 Conventionally, block device numbers are allocated from
1412 predetermined contiguous area. However, extended block area
1413 may introduce non-contiguous block device numbers. This
1414 option forces most block device numbers to be allocated from
1415 the extended space and spreads them to discover kernel or
1416 userland code paths which assume predetermined contiguous
1417 device number allocation.
1418
55dc7db7
TH
1419 Note that turning on this debug option shuffles all the
1420 device numbers for all IDE and SCSI devices including libata
1421 ones, so root partition specified using device number
1422 directly (via rdev or root=MAJ:MIN) won't work anymore.
1423 Textual device names (root=/dev/sdXn) will continue to work.
1424
870d6656
TH
1425 Say N if you are unsure.
1426
757c989b
TG
1427config CPU_HOTPLUG_STATE_CONTROL
1428 bool "Enable CPU hotplug state control"
1429 depends on DEBUG_KERNEL
1430 depends on HOTPLUG_CPU
1431 default n
1432 help
1433 Allows to write steps between "offline" and "online" to the CPUs
1434 sysfs target file so states can be stepped granular. This is a debug
1435 option for now as the hotplug machinery cannot be stopped and
1436 restarted at arbitrary points yet.
1437
1438 Say N if your are unsure.
1439
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CD
1440config LATENCYTOP
1441 bool "Latency measuring infrastructure"
1442 depends on DEBUG_KERNEL
1443 depends on STACKTRACE_SUPPORT
1444 depends on PROC_FS
1445 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1446 select KALLSYMS
1447 select KALLSYMS_ALL
1448 select STACKTRACE
1449 select SCHEDSTATS
1450 select SCHED_DEBUG
1451 help
1452 Enable this option if you want to use the LatencyTOP tool
1453 to find out which userspace is blocking on what kernel operations.
1454
1455source "kernel/trace/Kconfig"
1456
1457config PROVIDE_OHCI1394_DMA_INIT
1458 bool "Remote debugging over FireWire early on boot"
1459 depends on PCI && X86
1460 help
1461 If you want to debug problems which hang or crash the kernel early
1462 on boot and the crashing machine has a FireWire port, you can use
1463 this feature to remotely access the memory of the crashed machine
1464 over FireWire. This employs remote DMA as part of the OHCI1394
1465 specification which is now the standard for FireWire controllers.
1466
1467 With remote DMA, you can monitor the printk buffer remotely using
1468 firescope and access all memory below 4GB using fireproxy from gdb.
1469 Even controlling a kernel debugger is possible using remote DMA.
1470
1471 Usage:
1472
1473 If ohci1394_dma=early is used as boot parameter, it will initialize
1474 all OHCI1394 controllers which are found in the PCI config space.
1475
1476 As all changes to the FireWire bus such as enabling and disabling
1477 devices cause a bus reset and thereby disable remote DMA for all
1478 devices, be sure to have the cable plugged and FireWire enabled on
1479 the debugging host before booting the debug target for debugging.
1480
1481 This code (~1k) is freed after boot. By then, the firewire stack
1482 in charge of the OHCI-1394 controllers should be used instead.
1483
1484 See Documentation/debugging-via-ohci1394.txt for more information.
1485
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CD
1486source "samples/Kconfig"
1487
1488config ARCH_HAS_DEVMEM_IS_ALLOWED
1489 bool
1490
1491config STRICT_DEVMEM
1492 bool "Filter access to /dev/mem"
1493 depends on MMU && DEVMEM
1494 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
1495 default y if PPC || X86 || ARM64
1496 help
1497 If this option is disabled, you allow userspace (root) access to all
1498 of memory, including kernel and userspace memory. Accidental
1499 access to this is obviously disastrous, but specific access can
1500 be used by people debugging the kernel. Note that with PAT support
1501 enabled, even in this case there are restrictions on /dev/mem
1502 use due to the cache aliasing requirements.
1503
1504 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1505 file only allows userspace access to PCI space and the BIOS code and
1506 data regions. This is sufficient for dosemu and X and all common
1507 users of /dev/mem.
1508
1509 If in doubt, say Y.
1510
1511config IO_STRICT_DEVMEM
1512 bool "Filter I/O access to /dev/mem"
1513 depends on STRICT_DEVMEM
1514 help
1515 If this option is disabled, you allow userspace (root) access to all
1516 io-memory regardless of whether a driver is actively using that
1517 range. Accidental access to this is obviously disastrous, but
1518 specific access can be used by people debugging kernel drivers.
1519
1520 If this option is switched on, the /dev/mem file only allows
1521 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1522 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1523 if the driver using a given range cannot be disabled.
1524
1525 If in doubt, say Y.
1526
1527menu "$(SRCARCH) Debugging"
1528
1529source "arch/$(SRCARCH)/Kconfig.debug"
1530
1531endmenu
1532
1533menu "Kernel Testing and Coverage"
1534
09a74952
CD
1535source "lib/kunit/Kconfig"
1536
8d438288
AM
1537config NOTIFIER_ERROR_INJECTION
1538 tristate "Notifier error injection"
1539 depends on DEBUG_KERNEL
1540 select DEBUG_FS
1541 help
e41e85cc 1542 This option provides the ability to inject artificial errors to
8d438288
AM
1543 specified notifier chain callbacks. It is useful to test the error
1544 handling of notifier call chain failures.
1545
1546 Say N if unsure.
1547
048b9c35
AM
1548config PM_NOTIFIER_ERROR_INJECT
1549 tristate "PM notifier error injection module"
1550 depends on PM && NOTIFIER_ERROR_INJECTION
1551 default m if PM_DEBUG
1552 help
e41e85cc 1553 This option provides the ability to inject artificial errors to
048b9c35
AM
1554 PM notifier chain callbacks. It is controlled through debugfs
1555 interface /sys/kernel/debug/notifier-error-inject/pm
1556
1557 If the notifier call chain should be failed with some events
1558 notified, write the error code to "actions/<notifier event>/error".
1559
1560 Example: Inject PM suspend error (-12 = -ENOMEM)
1561
1562 # cd /sys/kernel/debug/notifier-error-inject/pm/
1563 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1564 # echo mem > /sys/power/state
1565 bash: echo: write error: Cannot allocate memory
1566
1567 To compile this code as a module, choose M here: the module will
1568 be called pm-notifier-error-inject.
1569
1570 If unsure, say N.
1571
d526e85f
BH
1572config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1573 tristate "OF reconfig notifier error injection module"
1574 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1575 help
e41e85cc 1576 This option provides the ability to inject artificial errors to
d526e85f 1577 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1578 through debugfs interface under
d526e85f 1579 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1580
1581 If the notifier call chain should be failed with some events
1582 notified, write the error code to "actions/<notifier event>/error".
1583
1584 To compile this code as a module, choose M here: the module will
e12a95f4 1585 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1586
1587 If unsure, say N.
1588
02fff96a
NA
1589config NETDEV_NOTIFIER_ERROR_INJECT
1590 tristate "Netdev notifier error injection module"
1591 depends on NET && NOTIFIER_ERROR_INJECTION
1592 help
1593 This option provides the ability to inject artificial errors to
1594 netdevice notifier chain callbacks. It is controlled through debugfs
1595 interface /sys/kernel/debug/notifier-error-inject/netdev
1596
1597 If the notifier call chain should be failed with some events
1598 notified, write the error code to "actions/<notifier event>/error".
1599
1600 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1601
1602 # cd /sys/kernel/debug/notifier-error-inject/netdev
1603 # echo -22 > actions/NETDEV_CHANGEMTU/error
1604 # ip link set eth0 mtu 1024
1605 RTNETLINK answers: Invalid argument
1606
1607 To compile this code as a module, choose M here: the module will
1608 be called netdev-notifier-error-inject.
1609
1610 If unsure, say N.
1611
f1b4bd06
MP
1612config FUNCTION_ERROR_INJECTION
1613 def_bool y
1614 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1615
6ff1cb35 1616config FAULT_INJECTION
1ab8509a
AM
1617 bool "Fault-injection framework"
1618 depends on DEBUG_KERNEL
329409ae
AM
1619 help
1620 Provide fault-injection framework.
1621 For more details, see Documentation/fault-injection/.
6ff1cb35 1622
8a8b6502 1623config FAILSLAB
1ab8509a
AM
1624 bool "Fault-injection capability for kmalloc"
1625 depends on FAULT_INJECTION
773ff60e 1626 depends on SLAB || SLUB
8a8b6502 1627 help
1ab8509a 1628 Provide fault-injection capability for kmalloc.
8a8b6502 1629
933e312e
AM
1630config FAIL_PAGE_ALLOC
1631 bool "Fault-injection capabilitiy for alloc_pages()"
1ab8509a 1632 depends on FAULT_INJECTION
933e312e 1633 help
1ab8509a 1634 Provide fault-injection capability for alloc_pages().
933e312e 1635
c17bb495 1636config FAIL_MAKE_REQUEST
86327d19 1637 bool "Fault-injection capability for disk IO"
581d4e28 1638 depends on FAULT_INJECTION && BLOCK
c17bb495 1639 help
1ab8509a 1640 Provide fault-injection capability for disk IO.
c17bb495 1641
581d4e28 1642config FAIL_IO_TIMEOUT
f4d01439 1643 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1644 depends on FAULT_INJECTION && BLOCK
1645 help
1646 Provide fault-injection capability on end IO handling. This
1647 will make the block layer "forget" an interrupt as configured,
1648 thus exercising the error handling.
1649
1650 Only works with drivers that use the generic timeout handling,
1651 for others it wont do anything.
1652
ab51fbab
DB
1653config FAIL_FUTEX
1654 bool "Fault-injection capability for futexes"
1655 select DEBUG_FS
1656 depends on FAULT_INJECTION && FUTEX
1657 help
1658 Provide fault-injection capability for futexes.
1659
f1b4bd06
MP
1660config FAULT_INJECTION_DEBUG_FS
1661 bool "Debugfs entries for fault-injection capabilities"
1662 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1663 help
1664 Enable configuration of fault-injection capabilities via debugfs.
1665
4b1a29a7
MH
1666config FAIL_FUNCTION
1667 bool "Fault-injection capability for functions"
1668 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1669 help
1670 Provide function-based fault-injection capability.
1671 This will allow you to override a specific function with a return
1672 with given return value. As a result, function caller will see
1673 an error value and have to handle it. This is useful to test the
1674 error handling in various subsystems.
1675
f1b4bd06
MP
1676config FAIL_MMC_REQUEST
1677 bool "Fault-injection capability for MMC IO"
1678 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1679 help
f1b4bd06
MP
1680 Provide fault-injection capability for MMC IO.
1681 This will make the mmc core return data errors. This is
1682 useful to test the error handling in the mmc block device
1683 and to test how the mmc host driver handles retries from
1684 the block device.
1df49008
AM
1685
1686config FAULT_INJECTION_STACKTRACE_FILTER
1687 bool "stacktrace filter for fault-injection capabilities"
1688 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1689 depends on !X86_64
1df49008 1690 select STACKTRACE
f9b58e8c 1691 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1df49008
AM
1692 help
1693 Provide stacktrace filter for fault-injection capabilities
267c4025 1694
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CD
1695config ARCH_HAS_KCOV
1696 bool
cc3fa840 1697 help
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CD
1698 An architecture should select this when it can successfully
1699 build and run with CONFIG_KCOV. This typically requires
1700 disabling instrumentation for some early boot code.
cc3fa840 1701
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CD
1702config CC_HAS_SANCOV_TRACE_PC
1703 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 1704
cc3fa840 1705
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CD
1706config KCOV
1707 bool "Code coverage for fuzzing"
1708 depends on ARCH_HAS_KCOV
1709 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1710 select DEBUG_FS
1711 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1712 help
1713 KCOV exposes kernel code coverage information in a form suitable
1714 for coverage-guided fuzzing (randomized testing).
cc3fa840 1715
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CD
1716 If RANDOMIZE_BASE is enabled, PC values will not be stable across
1717 different machines and across reboots. If you need stable PC values,
1718 disable RANDOMIZE_BASE.
cc3fa840 1719
09a74952 1720 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 1721
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CD
1722config KCOV_ENABLE_COMPARISONS
1723 bool "Enable comparison operands collection by KCOV"
1724 depends on KCOV
1725 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
1726 help
1727 KCOV also exposes operands of every comparison in the instrumented
1728 code along with operand sizes and PCs of the comparison instructions.
1729 These operands can be used by fuzzing engines to improve the quality
1730 of fuzzing coverage.
cc3fa840 1731
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CD
1732config KCOV_INSTRUMENT_ALL
1733 bool "Instrument all code by default"
1734 depends on KCOV
1735 default y
1736 help
1737 If you are doing generic system call fuzzing (like e.g. syzkaller),
1738 then you will want to instrument the whole kernel and you should
1739 say y here. If you are doing more targeted fuzzing (like e.g.
1740 filesystem fuzzing with AFL) then you will want to enable coverage
1741 for more specific subsets of files, and should say n here.
84bc809e 1742
d3deafaa
VL
1743menuconfig RUNTIME_TESTING_MENU
1744 bool "Runtime Testing"
908009e8 1745 def_bool y
d3deafaa
VL
1746
1747if RUNTIME_TESTING_MENU
881c5149
DH
1748
1749config LKDTM
1750 tristate "Linux Kernel Dump Test Tool Module"
1751 depends on DEBUG_FS
881c5149
DH
1752 help
1753 This module enables testing of the different dumping mechanisms by
1754 inducing system failures at predefined crash points.
1755 If you don't need it: say N
1756 Choose M here to compile this code as a module. The module will be
1757 called lkdtm.
1758
1759 Documentation on how to use the module can be found in
10ffebbe 1760 Documentation/fault-injection/provoke-crashes.rst
881c5149
DH
1761
1762config TEST_LIST_SORT
e327fd7c
GU
1763 tristate "Linked list sorting test"
1764 depends on DEBUG_KERNEL || m
881c5149
DH
1765 help
1766 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
1767 executed only once during system boot (so affects only boot time),
1768 or at module load time.
881c5149
DH
1769
1770 If unsure, say N.
1771
c5adae95 1772config TEST_SORT
5c4e6798
GU
1773 tristate "Array-based sort test"
1774 depends on DEBUG_KERNEL || m
c5adae95 1775 help
5c4e6798
GU
1776 This option enables the self-test function of 'sort()' at boot,
1777 or at module load time.
c5adae95
KF
1778
1779 If unsure, say N.
1780
881c5149
DH
1781config KPROBES_SANITY_TEST
1782 bool "Kprobes sanity tests"
1783 depends on DEBUG_KERNEL
1784 depends on KPROBES
881c5149
DH
1785 help
1786 This option provides for testing basic kprobes functionality on
5a6cf77f 1787 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
1788 verified for functionality.
1789
1790 Say N if you are unsure.
1791
1792config BACKTRACE_SELF_TEST
1793 tristate "Self test for the backtrace code"
1794 depends on DEBUG_KERNEL
881c5149
DH
1795 help
1796 This option provides a kernel module that can be used to test
1797 the kernel stack backtrace code. This option is not useful
1798 for distributions or general kernels, but only for kernel
1799 developers working on architecture code.
1800
1801 Note that if you want to also test saved backtraces, you will
1802 have to enable STACKTRACE as well.
1803
1804 Say N if you are unsure.
1805
910a742d
ML
1806config RBTREE_TEST
1807 tristate "Red-Black tree test"
7c993e11 1808 depends on DEBUG_KERNEL
910a742d
ML
1809 help
1810 A benchmark measuring the performance of the rbtree library.
1811 Also includes rbtree invariant checks.
1812
4b4f3acc
FB
1813config REED_SOLOMON_TEST
1814 tristate "Reed-Solomon library test"
1815 depends on DEBUG_KERNEL || m
1816 select REED_SOLOMON
1817 select REED_SOLOMON_ENC16
1818 select REED_SOLOMON_DEC16
1819 help
1820 This option enables the self-test function of rslib at boot,
1821 or at module load time.
1822
1823 If unsure, say N.
1824
fff3fd8a
ML
1825config INTERVAL_TREE_TEST
1826 tristate "Interval tree test"
0f789b67 1827 depends on DEBUG_KERNEL
a88cc108 1828 select INTERVAL_TREE
fff3fd8a
ML
1829 help
1830 A benchmark measuring the performance of the interval tree library
1831
623fd807
GT
1832config PERCPU_TEST
1833 tristate "Per cpu operations test"
1834 depends on m && DEBUG_KERNEL
1835 help
1836 Enable this option to build test module which validates per-cpu
1837 operations.
1838
1839 If unsure, say N.
1840
881c5149 1841config ATOMIC64_SELFTEST
55ded955 1842 tristate "Perform an atomic64_t self-test"
881c5149 1843 help
55ded955
GU
1844 Enable this option to test the atomic64_t functions at boot or
1845 at module load time.
881c5149
DH
1846
1847 If unsure, say N.
1848
1849config ASYNC_RAID6_TEST
1850 tristate "Self test for hardware accelerated raid6 recovery"
1851 depends on ASYNC_RAID6_RECOV
1852 select ASYNC_MEMCPY
1853 ---help---
1854 This is a one-shot self test that permutes through the
1855 recovery of all the possible two disk failure scenarios for a
1856 N-disk array. Recovery is performed with the asynchronous
1857 raid6 recovery routines, and will optionally use an offload
1858 engine if one is available.
1859
1860 If unsure, say N.
1861
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AS
1862config TEST_HEXDUMP
1863 tristate "Test functions located in the hexdump module at runtime"
1864
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DH
1865config TEST_STRING_HELPERS
1866 tristate "Test functions located in the string_helpers module at runtime"
1867
0b0600c8
TH
1868config TEST_STRSCPY
1869 tristate "Test strscpy*() family of functions at runtime"
1870
881c5149
DH
1871config TEST_KSTRTOX
1872 tristate "Test kstrto*() family of functions at runtime"
1873
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RV
1874config TEST_PRINTF
1875 tristate "Test printf() family of functions at runtime"
1876
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DD
1877config TEST_BITMAP
1878 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
1879 help
1880 Enable this option to test the bitmap functions at boot.
1881
1882 If unsure, say N.
1883
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JB
1884config TEST_BITFIELD
1885 tristate "Test bitfield functions at runtime"
1886 help
1887 Enable this option to test the bitfield functions at boot.
1888
1889 If unsure, say N.
1890
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AS
1891config TEST_UUID
1892 tristate "Test functions located in the uuid module at runtime"
1893
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MW
1894config TEST_XARRAY
1895 tristate "Test the XArray code at runtime"
1896
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RV
1897config TEST_OVERFLOW
1898 tristate "Test check_*_overflow() functions at runtime"
1899
7e1e7763 1900config TEST_RHASHTABLE
9d6dbe1b 1901 tristate "Perform selftest on resizable hash table"
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TG
1902 help
1903 Enable this option to test the rhashtable functions at boot.
1904
1905 If unsure, say N.
1906
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GS
1907config TEST_HASH
1908 tristate "Perform selftest on hash functions"
468a9428 1909 help
2c956a60
JD
1910 Enable this option to test the kernel's integer (<linux/hash.h>),
1911 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1912 hash functions on boot (or module load).
468a9428
GS
1913
1914 This is intended to help people writing architecture-specific
1915 optimized versions. If unsure, say N.
1916
8ab8ba38
MW
1917config TEST_IDA
1918 tristate "Perform selftest on IDA functions"
1919
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JP
1920config TEST_PARMAN
1921 tristate "Perform selftest on priority array manager"
44091d29
JP
1922 depends on PARMAN
1923 help
1924 Enable this option to test priority array manager on boot
1925 (or module load).
1926
1927 If unsure, say N.
1928
6aed82de
DL
1929config TEST_IRQ_TIMINGS
1930 bool "IRQ timings selftest"
1931 depends on IRQ_TIMINGS
1932 help
1933 Enable this option to test the irq timings code on boot.
1934
1935 If unsure, say N.
1936
8a6f0b47 1937config TEST_LKM
93e9ef83 1938 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
1939 depends on m
1940 help
1941 This builds the "test_module" module that emits "Hello, world"
1942 on printk when loaded. It is designed to be used for basic
1943 evaluation of the module loading subsystem (for example when
1944 validating module verification). It lacks any extra dependencies,
1945 and will not normally be loaded by the system unless explicitly
1946 requested by name.
1947
1948 If unsure, say N.
1949
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URS
1950config TEST_VMALLOC
1951 tristate "Test module for stress/performance analysis of vmalloc allocator"
1952 default n
1953 depends on MMU
1954 depends on m
1955 help
1956 This builds the "test_vmalloc" module that should be used for
1957 stress and performance analysis. So, any new change for vmalloc
1958 subsystem can be evaluated from performance and stability point
1959 of view.
1960
1961 If unsure, say N.
1962
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KC
1963config TEST_USER_COPY
1964 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
1965 depends on m
1966 help
1967 This builds the "test_user_copy" module that runs sanity checks
1968 on the copy_to/from_user infrastructure, making sure basic
1969 user/kernel boundary testing is working. If it fails to load,
1970 a regression has been detected in the user/kernel memory boundary
1971 protections.
1972
1973 If unsure, say N.
1974
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AS
1975config TEST_BPF
1976 tristate "Test BPF filter functionality"
98920ba6 1977 depends on m && NET
64a8946b
AS
1978 help
1979 This builds the "test_bpf" module that runs various test vectors
1980 against the BPF interpreter or BPF JIT compiler depending on the
1981 current setting. This is in particular useful for BPF JIT compiler
1982 development, but also to run regression tests against changes in
3c731eba
AS
1983 the interpreter code. It also enables test stubs for eBPF maps and
1984 verifier used by user space verifier testsuite.
64a8946b
AS
1985
1986 If unsure, say N.
1987
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MB
1988config TEST_BLACKHOLE_DEV
1989 tristate "Test blackhole netdev functionality"
1990 depends on m && NET
1991 help
1992 This builds the "test_blackhole_dev" module that validates the
1993 data path through this blackhole netdev.
1994
1995 If unsure, say N.
1996
dceeb3e7 1997config FIND_BIT_BENCHMARK
4441fca0 1998 tristate "Test find_bit functions"
4441fca0
YN
1999 help
2000 This builds the "test_find_bit" module that measure find_*_bit()
2001 functions performance.
2002
2003 If unsure, say N.
2004
0a8adf58
KC
2005config TEST_FIRMWARE
2006 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2007 depends on FW_LOADER
2008 help
2009 This builds the "test_firmware" module that creates a userspace
2010 interface for testing firmware loading. This can be used to
2011 control the triggering of firmware loading without needing an
2012 actual firmware-using device. The contents can be rechecked by
2013 userspace.
2014
2015 If unsure, say N.
2016
9308f2f9
LR
2017config TEST_SYSCTL
2018 tristate "sysctl test driver"
9308f2f9
LR
2019 depends on PROC_SYSCTL
2020 help
2021 This builds the "test_sysctl" module. This driver enables to test the
2022 proc sysctl interfaces available to drivers safely without affecting
2023 production knobs which might alter system functionality.
2024
2025 If unsure, say N.
2026
2cb80dbb 2027config SYSCTL_KUNIT_TEST
c475c77d 2028 tristate "KUnit test for sysctl"
2cb80dbb
IZ
2029 depends on KUNIT
2030 help
2031 This builds the proc sysctl unit test, which runs on boot.
2032 Tests the API contract and implementation correctness of sysctl.
2033 For more information on KUnit and unit tests in general please refer
2034 to the KUnit documentation in Documentation/dev-tools/kunit/.
2035
2036 If unsure, say N.
2037
ea2dd7c0 2038config LIST_KUNIT_TEST
c475c77d 2039 tristate "KUnit Test for Kernel Linked-list structures"
ea2dd7c0
DG
2040 depends on KUNIT
2041 help
2042 This builds the linked list KUnit test suite.
2043 It tests that the API and basic functionality of the list_head type
2044 and associated macros.
2045
2046 KUnit tests run during boot and output the results to the debug log
2047 in TAP format (http://testanything.org/). Only useful for kernel devs
2048 running the KUnit test harness, and not intended for inclusion into a
2049 production build.
2050
2051 For more information on KUnit and unit tests in general please refer
2052 to the KUnit documentation in Documentation/dev-tools/kunit/.
2053
2054 If unsure, say N.
2055
e704f93a
DR
2056config TEST_UDELAY
2057 tristate "udelay test driver"
e704f93a
DR
2058 help
2059 This builds the "udelay_test" module that helps to make sure
2060 that udelay() is working properly.
2061
2062 If unsure, say N.
2063
2bf9e0ab
IM
2064config TEST_STATIC_KEYS
2065 tristate "Test static keys"
579e1acb
JB
2066 depends on m
2067 help
2bf9e0ab 2068 Test the static key interfaces.
579e1acb
JB
2069
2070 If unsure, say N.
2071
d9c6a72d
LR
2072config TEST_KMOD
2073 tristate "kmod stress tester"
d9c6a72d 2074 depends on m
d9c6a72d 2075 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2076 depends on BLOCK
d9c6a72d
LR
2077 select TEST_LKM
2078 select XFS_FS
2079 select TUN
2080 select BTRFS_FS
2081 help
2082 Test the kernel's module loading mechanism: kmod. kmod implements
2083 support to load modules using the Linux kernel's usermode helper.
2084 This test provides a series of tests against kmod.
2085
2086 Although technically you can either build test_kmod as a module or
2087 into the kernel we disallow building it into the kernel since
2088 it stress tests request_module() and this will very likely cause
2089 some issues by taking over precious threads available from other
2090 module load requests, ultimately this could be fatal.
2091
2092 To run tests run:
2093
2094 tools/testing/selftests/kmod/kmod.sh --help
2095
2096 If unsure, say N.
2097
e4dace36
FF
2098config TEST_DEBUG_VIRTUAL
2099 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2100 depends on DEBUG_VIRTUAL
2101 help
2102 Test the kernel's ability to detect incorrect calls to
2103 virt_to_phys() done against the non-linear part of the
2104 kernel's virtual address map.
2105
2106 If unsure, say N.
2107
ce76d938
AS
2108config TEST_MEMCAT_P
2109 tristate "Test memcat_p() helper function"
2110 help
2111 Test the memcat_p() helper for correctly merging two
2112 pointer arrays together.
2113
2114 If unsure, say N.
2115
a2818ee4
JL
2116config TEST_LIVEPATCH
2117 tristate "Test livepatching"
2118 default n
bae05437 2119 depends on DYNAMIC_DEBUG
a2818ee4
JL
2120 depends on LIVEPATCH
2121 depends on m
2122 help
2123 Test kernel livepatching features for correctness. The tests will
2124 load test modules that will be livepatched in various scenarios.
2125
2126 To run all the livepatching tests:
2127
2128 make -C tools/testing/selftests TARGETS=livepatch run_tests
2129
2130 Alternatively, individual tests may be invoked:
2131
2132 tools/testing/selftests/livepatch/test-callbacks.sh
2133 tools/testing/selftests/livepatch/test-livepatch.sh
2134 tools/testing/selftests/livepatch/test-shadow-vars.sh
2135
2136 If unsure, say N.
2137
0a020d41
JP
2138config TEST_OBJAGG
2139 tristate "Perform selftest on object aggreration manager"
2140 default n
2141 depends on OBJAGG
2142 help
2143 Enable this option to test object aggregation manager on boot
2144 (or module load).
2145
0a020d41 2146
50ceaa95
KC
2147config TEST_STACKINIT
2148 tristate "Test level of stack variable initialization"
2149 help
2150 Test if the kernel is zero-initializing stack variables and
2151 padding. Coverage is controlled by compiler flags,
2152 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2153 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2154
2155 If unsure, say N.
2156
5015a300
AP
2157config TEST_MEMINIT
2158 tristate "Test heap/page initialization"
2159 help
2160 Test if the kernel is zero-initializing heap and page allocations.
2161 This can be useful to test init_on_alloc and init_on_free features.
2162
2163 If unsure, say N.
2164
d3deafaa 2165endif # RUNTIME_TESTING_MENU
cc3fa840
RD
2166
2167config MEMTEST
2168 bool "Memtest"
cc3fa840
RD
2169 ---help---
2170 This option adds a kernel parameter 'memtest', which allows memtest
2171 to be set.
2172 memtest=0, mean disabled; -- default
2173 memtest=1, mean do 1 test pattern;
2174 ...
2175 memtest=17, mean do 17 test patterns.
2176 If you are unsure how to answer this question, answer N.
2177
21266be9 2178
06ec64b8 2179
af9ca6f9
BB
2180config HYPERV_TESTING
2181 bool "Microsoft Hyper-V driver testing"
2182 default n
2183 depends on HYPERV && DEBUG_FS
2184 help
2185 Select this option to enable Hyper-V vmbus testing.
2186
045f6d79
CD
2187endmenu # "Kernel Testing and Coverage"
2188
06ec64b8 2189endmenu # Kernel hacking