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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
131 flags : '=p' means the line is turned 'on' for printing
132 format : the format used for the debug statement
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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176endmenu # "printk and dmesg options"
177
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178menu "Compile-time checks and compiler options"
179
180config DEBUG_INFO
181 bool "Compile the kernel with debug info"
12b13835 182 depends on DEBUG_KERNEL && !COMPILE_TEST
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183 help
184 If you say Y here the resulting kernel image will include
185 debugging info resulting in a larger kernel image.
186 This adds debug symbols to the kernel and modules (gcc -g), and
187 is needed if you intend to use kernel crashdump or binary object
188 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
189 Say Y here only if you plan to debug the kernel.
190
191 If unsure, say N.
192
193config DEBUG_INFO_REDUCED
194 bool "Reduce debugging information"
195 depends on DEBUG_INFO
196 help
197 If you say Y here gcc is instructed to generate less debugging
198 information for structure types. This means that tools that
199 need full debugging information (like kgdb or systemtap) won't
200 be happy. But if you merely need debugging information to
201 resolve line numbers there is no loss. Advantage is that
202 build directory object sizes shrink dramatically over a full
203 DEBUG_INFO build and compile times are reduced too.
204 Only works with newer gcc versions.
205
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206config DEBUG_INFO_SPLIT
207 bool "Produce split debuginfo in .dwo files"
a687a533 208 depends on DEBUG_INFO
9d937444 209 depends on $(cc-option,-gsplit-dwarf)
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210 help
211 Generate debug info into separate .dwo files. This significantly
212 reduces the build directory size for builds with DEBUG_INFO,
213 because it stores the information only once on disk in .dwo
214 files instead of multiple times in object files and executables.
215 In addition the debug information is also compressed.
216
217 Requires recent gcc (4.7+) and recent gdb/binutils.
218 Any tool that packages or reads debug information would need
219 to know about the .dwo files and include them.
220 Incompatible with older versions of ccache.
221
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222config DEBUG_INFO_DWARF4
223 bool "Generate dwarf4 debuginfo"
224 depends on DEBUG_INFO
9d937444 225 depends on $(cc-option,-gdwarf-4)
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226 help
227 Generate dwarf4 debug info. This requires recent versions
228 of gcc and gdb. It makes the debug information larger.
229 But it significantly improves the success of resolving
230 variables in gdb on optimized code.
231
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232config DEBUG_INFO_BTF
233 bool "Generate BTF typeinfo"
234 depends on DEBUG_INFO
235 help
236 Generate deduplicated BTF type information from DWARF debug info.
237 Turning this on expects presence of pahole tool, which will convert
238 DWARF type info into equivalent deduplicated BTF type info.
239
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240config GDB_SCRIPTS
241 bool "Provide GDB scripts for kernel debugging"
242 depends on DEBUG_INFO
243 help
244 This creates the required links to GDB helper scripts in the
245 build directory. If you load vmlinux into gdb, the helper
246 scripts will be automatically imported by gdb as well, and
247 additional functions are available to analyze a Linux kernel
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248 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
249 for further details.
3ee7b3fa 250
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251config ENABLE_MUST_CHECK
252 bool "Enable __must_check logic"
253 default y
254 help
255 Enable the __must_check logic in the kernel build. Disable this to
256 suppress the "warning: ignoring return value of 'foo', declared with
257 attribute warn_unused_result" messages.
1da177e4 258
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259config FRAME_WARN
260 int "Warn for stack frames larger than (needs gcc 4.4)"
261 range 0 8192
0e07f663 262 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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263 default 1280 if (!64BIT && PARISC)
264 default 1024 if (!64BIT && !PARISC)
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265 default 2048 if 64BIT
266 help
267 Tell gcc to warn at build time for stack frames larger than this.
268 Setting this too low will cause a lot of warnings.
269 Setting it to 0 disables the warning.
270 Requires gcc 4.4
271
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272config STRIP_ASM_SYMS
273 bool "Strip assembler-generated symbols during link"
274 default n
275 help
276 Strip internal assembler-generated symbols during a link (symbols
277 that look like '.Lxxx') so they don't pollute the output of
278 get_wchan() and suchlike.
279
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280config READABLE_ASM
281 bool "Generate readable assembler code"
282 depends on DEBUG_KERNEL
283 help
284 Disable some compiler optimizations that tend to generate human unreadable
285 assembler output. This may make the kernel slightly slower, but it helps
286 to keep kernel developers who have to stare a lot at assembler listings
287 sane.
288
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289config DEBUG_FS
290 bool "Debug Filesystem"
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291 help
292 debugfs is a virtual file system that kernel developers use to put
293 debugging files into. Enable this option to be able to read and
294 write to these files.
295
ff543332 296 For detailed documentation on the debugfs API, see
e1b4fc7a 297 Documentation/filesystems/.
ff543332 298
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299 If unsure, say N.
300
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301config HEADERS_INSTALL
302 bool "Install uapi headers to usr/include"
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303 depends on !UML
304 help
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305 This option will install uapi headers (headers exported to user-space)
306 into the usr/include directory for use during the kernel build.
307 This is unneeded for building the kernel itself, but needed for some
308 user-space program samples. It is also needed by some features such
309 as uapi header sanity checks.
310
bf4735a4 311config HEADERS_CHECK
c6509a24 312 bool "Run sanity checks on uapi headers when building 'all'"
e949f4c2 313 depends on HEADERS_INSTALL
bf4735a4 314 help
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315 This option will run basic sanity checks on uapi headers when
316 building the 'all' target, for example, ensure that they do not
317 attempt to include files which were not exported, etc.
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318
319 If you're making modifications to header files which are
59b2bd05 320 relevant for userspace, say 'Y'.
bf4735a4 321
9012d011 322config OPTIMIZE_INLINING
ac7c3e4f 323 def_bool y
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324 help
325 This option determines if the kernel forces gcc to inline the functions
326 developers have marked 'inline'. Doing so takes away freedom from gcc to
327 do what it thinks is best, which is desirable for the gcc 3.x series of
328 compilers. The gcc 4.x series have a rewritten inlining algorithm and
329 enabling this option will generate a smaller kernel there. Hopefully
330 this algorithm is so good that allowing gcc 4.x and above to make the
331 decision will become the default in the future. Until then this option
332 is there to test gcc for this.
333
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334config DEBUG_SECTION_MISMATCH
335 bool "Enable full Section mismatch analysis"
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336 help
337 The section mismatch analysis checks if there are illegal
338 references from one section to another section.
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339 During linktime or runtime, some sections are dropped;
340 any use of code/data previously in these sections would
91341d4b 341 most likely result in an oops.
e809ab01 342 In the code, functions and variables are annotated with
0db0628d 343 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 344 which results in the code/data being placed in specific sections.
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345 The section mismatch analysis is always performed after a full
346 kernel build, and enabling this option causes the following
b7dca6dd 347 additional step to occur:
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348 - Add the option -fno-inline-functions-called-once to gcc commands.
349 When inlining a function annotated with __init in a non-init
350 function, we would lose the section information and thus
91341d4b 351 the analysis would not catch the illegal reference.
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352 This option tells gcc to inline less (but it does result in
353 a larger kernel).
91341d4b 354
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355config SECTION_MISMATCH_WARN_ONLY
356 bool "Make section mismatch errors non-fatal"
357 default y
358 help
359 If you say N here, the build process will fail if there are any
360 section mismatch, instead of just throwing warnings.
361
362 If unsure, say Y.
363
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364#
365# Select this config option from the architecture Kconfig, if it
366# is preferred to always offer frame pointers as a config
367# option on the architecture (regardless of KERNEL_DEBUG):
368#
369config ARCH_WANT_FRAME_POINTERS
370 bool
f346f4b3 371
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372config FRAME_POINTER
373 bool "Compile the kernel with frame pointers"
a687a533 374 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 375 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 376 help
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377 If you say Y here the resulting kernel image will be slightly
378 larger and slower, but it gives very useful debugging information
379 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 380
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381config STACK_VALIDATION
382 bool "Compile-time stack metadata validation"
383 depends on HAVE_STACK_VALIDATION
384 default n
385 help
386 Add compile-time checks to validate stack metadata, including frame
387 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
388 that runtime stack traces are more reliable.
389
ee9f8fce 390 This is also a prerequisite for generation of ORC unwind data, which
11af8474 391 is needed for CONFIG_UNWINDER_ORC.
ee9f8fce 392
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393 For more information, see
394 tools/objtool/Documentation/stack-validation.txt.
395
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396config DEBUG_FORCE_WEAK_PER_CPU
397 bool "Force weak per-cpu definitions"
398 depends on DEBUG_KERNEL
8446f1d3 399 help
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400 s390 and alpha require percpu variables in modules to be
401 defined weak to work around addressing range issue which
402 puts the following two restrictions on percpu variable
403 definitions.
8446f1d3 404
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405 1. percpu symbols must be unique whether static or not
406 2. percpu variables can't be defined inside a function
8446f1d3 407
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408 To ensure that generic code follows the above rules, this
409 option forces all percpu variables to be defined as weak.
5f329089 410
6dfc0665 411endmenu # "Compiler options"
8446f1d3 412
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413config MAGIC_SYSRQ
414 bool "Magic SysRq key"
415 depends on !UML
416 help
417 If you say Y here, you will have some control over the system even
418 if the system crashes for example during kernel debugging (e.g., you
419 will be able to flush the buffer cache to disk, reboot the system
420 immediately or dump some status information). This is accomplished
421 by pressing various keys while holding SysRq (Alt+PrintScreen). It
422 also works on a serial console (on PC hardware at least), if you
423 send a BREAK and then within 5 seconds a command keypress. The
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424 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
425 Don't say Y unless you really know what this hack does.
8446f1d3 426
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427config MAGIC_SYSRQ_DEFAULT_ENABLE
428 hex "Enable magic SysRq key functions by default"
429 depends on MAGIC_SYSRQ
430 default 0x1
431 help
432 Specifies which SysRq key functions are enabled by default.
433 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 434 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 435
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436config MAGIC_SYSRQ_SERIAL
437 bool "Enable magic SysRq key over serial"
438 depends on MAGIC_SYSRQ
439 default y
440 help
441 Many embedded boards have a disconnected TTL level serial which can
442 generate some garbage that can lead to spurious false sysrq detects.
443 This option allows you to decide whether you want to enable the
444 magic SysRq key.
445
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446config DEBUG_KERNEL
447 bool "Kernel debugging"
fef2c9bc 448 help
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449 Say Y here if you are developing drivers or trying to debug and
450 identify kernel problems.
fef2c9bc 451
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452config DEBUG_MISC
453 bool "Miscellaneous debug code"
454 default DEBUG_KERNEL
455 depends on DEBUG_KERNEL
456 help
457 Say Y here if you need to enable miscellaneous debug code that should
458 be under a more specific debug option but isn't.
459
460
0610c8a8 461menu "Memory Debugging"
fef2c9bc 462
8636a1f9 463source "mm/Kconfig.debug"
fef2c9bc 464
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465config DEBUG_OBJECTS
466 bool "Debug object operations"
467 depends on DEBUG_KERNEL
9c44bc03 468 help
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469 If you say Y here, additional code will be inserted into the
470 kernel to track the life time of various objects and validate
471 the operations on those objects.
9c44bc03 472
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473config DEBUG_OBJECTS_SELFTEST
474 bool "Debug objects selftest"
475 depends on DEBUG_OBJECTS
476 help
477 This enables the selftest of the object debug code.
9c44bc03 478
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479config DEBUG_OBJECTS_FREE
480 bool "Debug objects in freed memory"
481 depends on DEBUG_OBJECTS
482 help
483 This enables checks whether a k/v free operation frees an area
484 which contains an object which has not been deactivated
485 properly. This can make kmalloc/kfree-intensive workloads
486 much slower.
3ac7fe5a 487
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488config DEBUG_OBJECTS_TIMERS
489 bool "Debug timer objects"
490 depends on DEBUG_OBJECTS
491 help
492 If you say Y here, additional code will be inserted into the
493 timer routines to track the life time of timer objects and
494 validate the timer operations.
495
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496config DEBUG_OBJECTS_WORK
497 bool "Debug work objects"
498 depends on DEBUG_OBJECTS
499 help
500 If you say Y here, additional code will be inserted into the
501 work queue routines to track the life time of work objects and
502 validate the work operations.
503
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504config DEBUG_OBJECTS_RCU_HEAD
505 bool "Debug RCU callbacks objects"
fc2ecf7e 506 depends on DEBUG_OBJECTS
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507 help
508 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
509
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510config DEBUG_OBJECTS_PERCPU_COUNTER
511 bool "Debug percpu counter objects"
512 depends on DEBUG_OBJECTS
513 help
514 If you say Y here, additional code will be inserted into the
515 percpu counter routines to track the life time of percpu counter
516 objects and validate the percpu counter operations.
517
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518config DEBUG_OBJECTS_ENABLE_DEFAULT
519 int "debug_objects bootup default value (0-1)"
520 range 0 1
521 default "1"
522 depends on DEBUG_OBJECTS
523 help
524 Debug objects boot parameter default value
525
1da177e4 526config DEBUG_SLAB
4a2f0acf 527 bool "Debug slab memory allocations"
4675ff05 528 depends on DEBUG_KERNEL && SLAB
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529 help
530 Say Y here to have the kernel do limited verification on memory
531 allocation as well as poisoning memory on free to catch use of freed
532 memory. This can make kmalloc/kfree-intensive workloads much slower.
533
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534config SLUB_DEBUG_ON
535 bool "SLUB debugging on by default"
4675ff05 536 depends on SLUB && SLUB_DEBUG
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537 default n
538 help
539 Boot with debugging on by default. SLUB boots by default with
540 the runtime debug capabilities switched off. Enabling this is
541 equivalent to specifying the "slub_debug" parameter on boot.
542 There is no support for more fine grained debug control like
543 possible with slub_debug=xxx. SLUB debugging may be switched
544 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
545 "slub_debug=-".
546
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547config SLUB_STATS
548 default n
549 bool "Enable SLUB performance statistics"
ab4d5ed5 550 depends on SLUB && SYSFS
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551 help
552 SLUB statistics are useful to debug SLUBs allocation behavior in
553 order find ways to optimize the allocator. This should never be
554 enabled for production use since keeping statistics slows down
555 the allocator by a few percentage points. The slabinfo command
556 supports the determination of the most active slabs to figure
557 out which slabs are relevant to a particular load.
558 Try running: slabinfo -DA
559
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560config HAVE_DEBUG_KMEMLEAK
561 bool
562
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563config DEBUG_KMEMLEAK
564 bool "Kernel memory leak detector"
525c1f92 565 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 566 select DEBUG_FS
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567 select STACKTRACE if STACKTRACE_SUPPORT
568 select KALLSYMS
b60e26a2 569 select CRC32
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570 help
571 Say Y here if you want to enable the memory leak
572 detector. The memory allocation/freeing is traced in a way
573 similar to the Boehm's conservative garbage collector, the
574 difference being that the orphan objects are not freed but
575 only shown in /sys/kernel/debug/kmemleak. Enabling this
576 feature will introduce an overhead to memory
700199b0 577 allocations. See Documentation/dev-tools/kmemleak.rst for more
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578 details.
579
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580 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
581 of finding leaks due to the slab objects poisoning.
582
583 In order to access the kmemleak file, debugfs needs to be
584 mounted (usually at /sys/kernel/debug).
585
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586config DEBUG_KMEMLEAK_MEM_POOL_SIZE
587 int "Kmemleak memory pool size"
0610c8a8 588 depends on DEBUG_KMEMLEAK
c59180ae 589 range 200 1000000
b751c52b 590 default 16000
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591 help
592 Kmemleak must track all the memory allocations to avoid
593 reporting false positives. Since memory may be allocated or
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594 freed before kmemleak is fully initialised, use a static pool
595 of metadata objects to track such callbacks. After kmemleak is
596 fully initialised, this memory pool acts as an emergency one
597 if slab allocations fail.
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598
599config DEBUG_KMEMLEAK_TEST
600 tristate "Simple test for the kernel memory leak detector"
601 depends on DEBUG_KMEMLEAK && m
602 help
603 This option enables a module that explicitly leaks memory.
604
605 If unsure, say N.
606
607config DEBUG_KMEMLEAK_DEFAULT_OFF
608 bool "Default kmemleak to off"
609 depends on DEBUG_KMEMLEAK
610 help
611 Say Y here to disable kmemleak by default. It can then be enabled
612 on the command line via kmemleak=on.
613
d53ce042
SK
614config DEBUG_KMEMLEAK_AUTO_SCAN
615 bool "Enable kmemleak auto scan thread on boot up"
616 default y
617 depends on DEBUG_KMEMLEAK
618 help
619 Depending on the cpu, kmemleak scan may be cpu intensive and can
620 stall user tasks at times. This option enables/disables automatic
621 kmemleak scan at boot up.
622
623 Say N here to disable kmemleak auto scan thread to stop automatic
624 scanning. Disabling this option disables automatic reporting of
625 memory leaks.
626
627 If unsure, say Y.
628
0610c8a8
DH
629config DEBUG_STACK_USAGE
630 bool "Stack utilization instrumentation"
6c31da34 631 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
632 help
633 Enables the display of the minimum amount of free stack which each
634 task has ever had available in the sysrq-T and sysrq-P debug output.
635
636 This option will slow down process creation somewhat.
637
638config DEBUG_VM
639 bool "Debug VM"
640 depends on DEBUG_KERNEL
641 help
642 Enable this to turn on extended checks in the virtual-memory system
643 that may impact performance.
644
645 If unsure, say N.
646
4f115147
DB
647config DEBUG_VM_VMACACHE
648 bool "Debug VMA caching"
649 depends on DEBUG_VM
650 help
651 Enable this to turn on VMA caching debug information. Doing so
652 can cause significant overhead, so only enable it in non-production
653 environments.
654
655 If unsure, say N.
656
0610c8a8
DH
657config DEBUG_VM_RB
658 bool "Debug VM red-black trees"
659 depends on DEBUG_VM
660 help
a663dad6 661 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
662
663 If unsure, say N.
664
95ad9755
KS
665config DEBUG_VM_PGFLAGS
666 bool "Debug page-flags operations"
667 depends on DEBUG_VM
668 help
669 Enables extra validation on page flags operations.
670
671 If unsure, say N.
672
fa5b6ec9
LA
673config ARCH_HAS_DEBUG_VIRTUAL
674 bool
675
0610c8a8
DH
676config DEBUG_VIRTUAL
677 bool "Debug VM translations"
fa5b6ec9 678 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
679 help
680 Enable some costly sanity checks in virtual to page code. This can
681 catch mistakes with virt_to_page() and friends.
682
683 If unsure, say N.
684
685config DEBUG_NOMMU_REGIONS
686 bool "Debug the global anon/private NOMMU mapping region tree"
687 depends on DEBUG_KERNEL && !MMU
688 help
689 This option causes the global tree of anonymous and private mapping
690 regions to be regularly checked for invalid topology.
691
692config DEBUG_MEMORY_INIT
693 bool "Debug memory initialisation" if EXPERT
694 default !EXPERT
695 help
696 Enable this for additional checks during memory initialisation.
697 The sanity checks verify aspects of the VM such as the memory model
698 and other information provided by the architecture. Verbose
699 information will be printed at KERN_DEBUG loglevel depending
700 on the mminit_loglevel= command-line option.
701
702 If unsure, say Y
703
704config MEMORY_NOTIFIER_ERROR_INJECT
705 tristate "Memory hotplug notifier error injection module"
706 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
707 help
708 This option provides the ability to inject artificial errors to
709 memory hotplug notifier chain callbacks. It is controlled through
710 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
711
712 If the notifier call chain should be failed with some events
713 notified, write the error code to "actions/<notifier event>/error".
714
715 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
716
717 # cd /sys/kernel/debug/notifier-error-inject/memory
718 # echo -12 > actions/MEM_GOING_OFFLINE/error
719 # echo offline > /sys/devices/system/memory/memoryXXX/state
720 bash: echo: write error: Cannot allocate memory
721
722 To compile this code as a module, choose M here: the module will
723 be called memory-notifier-error-inject.
724
725 If unsure, say N.
726
727config DEBUG_PER_CPU_MAPS
728 bool "Debug access to per_cpu maps"
729 depends on DEBUG_KERNEL
730 depends on SMP
731 help
732 Say Y to verify that the per_cpu map being accessed has
733 been set up. This adds a fair amount of code to kernel memory
734 and decreases performance.
735
736 Say N if unsure.
737
738config DEBUG_HIGHMEM
739 bool "Highmem debugging"
740 depends on DEBUG_KERNEL && HIGHMEM
741 help
b1357c9f
GU
742 This option enables additional error checking for high memory
743 systems. Disable for production systems.
0610c8a8
DH
744
745config HAVE_DEBUG_STACKOVERFLOW
746 bool
747
748config DEBUG_STACKOVERFLOW
749 bool "Check for stack overflows"
750 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
751 ---help---
752 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 753 and exception stacks (if your architecture uses them). This
0610c8a8
DH
754 option will show detailed messages if free stack space drops
755 below a certain limit.
756
757 These kinds of bugs usually occur when call-chains in the
758 kernel get too deep, especially when interrupts are
759 involved.
760
761 Use this in cases where you see apparently random memory
762 corruption, especially if it appears in 'struct thread_info'
763
764 If in doubt, say "N".
765
0b24becc
AR
766source "lib/Kconfig.kasan"
767
0610c8a8
DH
768endmenu # "Memory Debugging"
769
5c9a8750
DV
770config ARCH_HAS_KCOV
771 bool
772 help
40453c4f
MR
773 An architecture should select this when it can successfully
774 build and run with CONFIG_KCOV. This typically requires
775 disabling instrumentation for some early boot code.
5c9a8750 776
5aadfdeb
MY
777config CC_HAS_SANCOV_TRACE_PC
778 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
779
5c9a8750
DV
780config KCOV
781 bool "Code coverage for fuzzing"
782 depends on ARCH_HAS_KCOV
5aadfdeb 783 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
5c9a8750 784 select DEBUG_FS
5aadfdeb 785 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
5c9a8750
DV
786 help
787 KCOV exposes kernel code coverage information in a form suitable
788 for coverage-guided fuzzing (randomized testing).
789
790 If RANDOMIZE_BASE is enabled, PC values will not be stable across
791 different machines and across reboots. If you need stable PC values,
792 disable RANDOMIZE_BASE.
793
700199b0 794 For more details, see Documentation/dev-tools/kcov.rst.
5c9a8750 795
d677a4d6
VC
796config KCOV_ENABLE_COMPARISONS
797 bool "Enable comparison operands collection by KCOV"
798 depends on KCOV
5aadfdeb 799 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
d677a4d6
VC
800 help
801 KCOV also exposes operands of every comparison in the instrumented
802 code along with operand sizes and PCs of the comparison instructions.
803 These operands can be used by fuzzing engines to improve the quality
804 of fuzzing coverage.
805
a4691dea
VN
806config KCOV_INSTRUMENT_ALL
807 bool "Instrument all code by default"
808 depends on KCOV
5aadfdeb 809 default y
a4691dea
VN
810 help
811 If you are doing generic system call fuzzing (like e.g. syzkaller),
812 then you will want to instrument the whole kernel and you should
813 say y here. If you are doing more targeted fuzzing (like e.g.
814 filesystem fuzzing with AFL) then you will want to enable coverage
815 for more specific subsets of files, and should say n here.
816
a304e1b8
DW
817config DEBUG_SHIRQ
818 bool "Debug shared IRQ handlers"
0244ad00 819 depends on DEBUG_KERNEL
a304e1b8
DW
820 help
821 Enable this to generate a spurious interrupt as soon as a shared
822 interrupt handler is registered, and just before one is deregistered.
823 Drivers ought to be able to handle interrupts coming in at those
824 points; some don't and need to be caught.
825
92aef8fb
DH
826menu "Debug Lockups and Hangs"
827
58687acb 828config LOCKUP_DETECTOR
05a4a952
NP
829 bool
830
831config SOFTLOCKUP_DETECTOR
832 bool "Detect Soft Lockups"
dea20a3f 833 depends on DEBUG_KERNEL && !S390
05a4a952 834 select LOCKUP_DETECTOR
8446f1d3 835 help
58687acb 836 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 837 soft lockups.
58687acb
DZ
838
839 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 840 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
841 chance to run. The current stack trace is displayed upon
842 detection and the system will stay locked up.
8446f1d3 843
5f00ae0d
RD
844config BOOTPARAM_SOFTLOCKUP_PANIC
845 bool "Panic (Reboot) On Soft Lockups"
846 depends on SOFTLOCKUP_DETECTOR
847 help
848 Say Y here to enable the kernel to panic on "soft lockups",
849 which are bugs that cause the kernel to loop in kernel
850 mode for more than 20 seconds (configurable using the watchdog_thresh
851 sysctl), without giving other tasks a chance to run.
852
853 The panic can be used in combination with panic_timeout,
854 to cause the system to reboot automatically after a
855 lockup has been detected. This feature is useful for
856 high-availability systems that have uptime guarantees and
857 where a lockup must be resolved ASAP.
858
859 Say N if unsure.
860
861config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
862 int
863 depends on SOFTLOCKUP_DETECTOR
864 range 0 1
865 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
866 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
867
05a4a952
NP
868config HARDLOCKUP_DETECTOR_PERF
869 bool
870 select SOFTLOCKUP_DETECTOR
871
7edaeb68
TG
872#
873# Enables a timestamp based low pass filter to compensate for perf based
874# hard lockup detection which runs too fast due to turbo modes.
875#
876config HARDLOCKUP_CHECK_TIMESTAMP
877 bool
878
05a4a952
NP
879#
880# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
881# lockup detector rather than the perf based detector.
882#
883config HARDLOCKUP_DETECTOR
884 bool "Detect Hard Lockups"
885 depends on DEBUG_KERNEL && !S390
886 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
887 select LOCKUP_DETECTOR
888 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
889 select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH
890 help
891 Say Y here to enable the kernel to act as a watchdog to detect
892 hard lockups.
893
58687acb 894 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 895 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
896 chance to run. The current stack trace is displayed upon detection
897 and the system will stay locked up.
8446f1d3 898
fef2c9bc
DZ
899config BOOTPARAM_HARDLOCKUP_PANIC
900 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 901 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
902 help
903 Say Y here to enable the kernel to panic on "hard lockups",
904 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
905 mode with interrupts disabled for more than 10 seconds (configurable
906 using the watchdog_thresh sysctl).
fef2c9bc
DZ
907
908 Say N if unsure.
909
910config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
911 int
8f1f66ed 912 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
913 range 0 1
914 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
915 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
916
e162b39a
MSB
917config DETECT_HUNG_TASK
918 bool "Detect Hung Tasks"
919 depends on DEBUG_KERNEL
05a4a952 920 default SOFTLOCKUP_DETECTOR
e162b39a 921 help
0610c8a8
DH
922 Say Y here to enable the kernel to detect "hung tasks",
923 which are bugs that cause the task to be stuck in
96b03ab8 924 uninterruptible "D" state indefinitely.
1da177e4 925
0610c8a8
DH
926 When a hung task is detected, the kernel will print the
927 current stack trace (which you should report), but the
928 task will stay in uninterruptible state. If lockdep is
929 enabled then all held locks will also be reported. This
930 feature has negligible overhead.
871751e2 931
0610c8a8
DH
932config DEFAULT_HUNG_TASK_TIMEOUT
933 int "Default timeout for hung task detection (in seconds)"
934 depends on DETECT_HUNG_TASK
935 default 120
f0630fff 936 help
0610c8a8
DH
937 This option controls the default timeout (in seconds) used
938 to determine when a task has become non-responsive and should
939 be considered hung.
f0630fff 940
0610c8a8
DH
941 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
942 sysctl or by writing a value to
943 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 944
0610c8a8
DH
945 A timeout of 0 disables the check. The default is two minutes.
946 Keeping the default should be fine in most cases.
b69ec42b 947
0610c8a8
DH
948config BOOTPARAM_HUNG_TASK_PANIC
949 bool "Panic (Reboot) On Hung Tasks"
950 depends on DETECT_HUNG_TASK
3bba00d7 951 help
0610c8a8
DH
952 Say Y here to enable the kernel to panic on "hung tasks",
953 which are bugs that cause the kernel to leave a task stuck
954 in uninterruptible "D" state.
3bba00d7 955
0610c8a8
DH
956 The panic can be used in combination with panic_timeout,
957 to cause the system to reboot automatically after a
958 hung task has been detected. This feature is useful for
959 high-availability systems that have uptime guarantees and
960 where a hung tasks must be resolved ASAP.
bf96d1e3 961
0610c8a8 962 Say N if unsure.
bf96d1e3 963
0610c8a8
DH
964config BOOTPARAM_HUNG_TASK_PANIC_VALUE
965 int
966 depends on DETECT_HUNG_TASK
967 range 0 1
968 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
969 default 1 if BOOTPARAM_HUNG_TASK_PANIC
3bba00d7 970
82607adc
TH
971config WQ_WATCHDOG
972 bool "Detect Workqueue Stalls"
973 depends on DEBUG_KERNEL
974 help
975 Say Y here to enable stall detection on workqueues. If a
976 worker pool doesn't make forward progress on a pending work
977 item for over a given amount of time, 30s by default, a
978 warning message is printed along with dump of workqueue
979 state. This can be configured through kernel parameter
980 "workqueue.watchdog_thresh" and its sysfs counterpart.
981
92aef8fb
DH
982endmenu # "Debug lockups and hangs"
983
984config PANIC_ON_OOPS
985 bool "Panic on Oops"
a9d9058a 986 help
92aef8fb
DH
987 Say Y here to enable the kernel to panic when it oopses. This
988 has the same effect as setting oops=panic on the kernel command
989 line.
a9d9058a 990
92aef8fb
DH
991 This feature is useful to ensure that the kernel does not do
992 anything erroneous after an oops which could result in data
993 corruption or other issues.
994
995 Say N if unsure.
996
997config PANIC_ON_OOPS_VALUE
998 int
999 range 0 1
1000 default 0 if !PANIC_ON_OOPS
1001 default 1 if PANIC_ON_OOPS
1002
5800dc3c
JB
1003config PANIC_TIMEOUT
1004 int "panic timeout"
1005 default 0
1006 help
1007 Set the timeout value (in seconds) until a reboot occurs when the
1008 the kernel panics. If n = 0, then we wait forever. A timeout
1009 value n > 0 will wait n seconds before rebooting, while a timeout
1010 value n < 0 will reboot immediately.
1011
0610c8a8
DH
1012config SCHED_DEBUG
1013 bool "Collect scheduler debugging info"
1014 depends on DEBUG_KERNEL && PROC_FS
1015 default y
0822ee4a 1016 help
0610c8a8
DH
1017 If you say Y here, the /proc/sched_debug file will be provided
1018 that can help debug the scheduler. The runtime overhead of this
1019 option is minimal.
0822ee4a 1020
f6db8347
NR
1021config SCHED_INFO
1022 bool
1023 default n
1024
0610c8a8
DH
1025config SCHEDSTATS
1026 bool "Collect scheduler statistics"
1027 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1028 select SCHED_INFO
0610c8a8
DH
1029 help
1030 If you say Y here, additional code will be inserted into the
1031 scheduler and related routines to collect statistics about
1032 scheduler behavior and provide them in /proc/schedstat. These
1033 stats may be useful for both tuning and debugging the scheduler
1034 If you aren't debugging the scheduler or trying to tune a specific
1035 application, you can say N to avoid the very slight overhead
1036 this adds.
0822ee4a 1037
0d9e2632
AT
1038config SCHED_STACK_END_CHECK
1039 bool "Detect stack corruption on calls to schedule()"
1040 depends on DEBUG_KERNEL
1041 default n
1042 help
1043 This option checks for a stack overrun on calls to schedule().
1044 If the stack end location is found to be over written always panic as
1045 the content of the corrupted region can no longer be trusted.
1046 This is to ensure no erroneous behaviour occurs which could result in
1047 data corruption or a sporadic crash at a later stage once the region
1048 is examined. The runtime overhead introduced is minimal.
1049
3c17ad19
JS
1050config DEBUG_TIMEKEEPING
1051 bool "Enable extra timekeeping sanity checking"
1052 help
1053 This option will enable additional timekeeping sanity checks
1054 which may be helpful when diagnosing issues where timekeeping
1055 problems are suspected.
1056
1057 This may include checks in the timekeeping hotpaths, so this
1058 option may have a (very small) performance impact to some
1059 workloads.
1060
1061 If unsure, say N.
1062
1da177e4
LT
1063config DEBUG_PREEMPT
1064 bool "Debug preemptible kernel"
01deab98 1065 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1066 default y
1067 help
1068 If you say Y here then the kernel will use a debug variant of the
1069 commonly used smp_processor_id() function and will print warnings
1070 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1071 will detect preemption count underflows.
1072
9eade16b
DH
1073menu "Lock Debugging (spinlocks, mutexes, etc...)"
1074
f07cbebb
WL
1075config LOCK_DEBUGGING_SUPPORT
1076 bool
1077 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1078 default y
1079
19193bca
WL
1080config PROVE_LOCKING
1081 bool "Lock debugging: prove locking correctness"
1082 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1083 select LOCKDEP
1084 select DEBUG_SPINLOCK
1085 select DEBUG_MUTEXES
1086 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1087 select DEBUG_RWSEMS
19193bca
WL
1088 select DEBUG_WW_MUTEX_SLOWPATH
1089 select DEBUG_LOCK_ALLOC
1090 select TRACE_IRQFLAGS
1091 default n
1092 help
1093 This feature enables the kernel to prove that all locking
1094 that occurs in the kernel runtime is mathematically
1095 correct: that under no circumstance could an arbitrary (and
1096 not yet triggered) combination of observed locking
1097 sequences (on an arbitrary number of CPUs, running an
1098 arbitrary number of tasks and interrupt contexts) cause a
1099 deadlock.
1100
1101 In short, this feature enables the kernel to report locking
1102 related deadlocks before they actually occur.
1103
1104 The proof does not depend on how hard and complex a
1105 deadlock scenario would be to trigger: how many
1106 participant CPUs, tasks and irq-contexts would be needed
1107 for it to trigger. The proof also does not depend on
1108 timing: if a race and a resulting deadlock is possible
1109 theoretically (no matter how unlikely the race scenario
1110 is), it will be proven so and will immediately be
1111 reported by the kernel (once the event is observed that
1112 makes the deadlock theoretically possible).
1113
1114 If a deadlock is impossible (i.e. the locking rules, as
1115 observed by the kernel, are mathematically correct), the
1116 kernel reports nothing.
1117
1118 NOTE: this feature can also be enabled for rwlocks, mutexes
1119 and rwsems - in which case all dependencies between these
1120 different locking variants are observed and mapped too, and
1121 the proof of observed correctness is also maintained for an
1122 arbitrary combination of these separate locking variants.
1123
387b1468 1124 For more details, see Documentation/locking/lockdep-design.rst.
19193bca
WL
1125
1126config LOCK_STAT
1127 bool "Lock usage statistics"
1128 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1129 select LOCKDEP
1130 select DEBUG_SPINLOCK
1131 select DEBUG_MUTEXES
1132 select DEBUG_RT_MUTEXES if RT_MUTEXES
1133 select DEBUG_LOCK_ALLOC
1134 default n
1135 help
1136 This feature enables tracking lock contention points
1137
387b1468 1138 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1139
1140 This also enables lock events required by "perf lock",
1141 subcommand of perf.
1142 If you want to use "perf lock", you also need to turn on
1143 CONFIG_EVENT_TRACING.
1144
1145 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1146 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1147
e7eebaf6
IM
1148config DEBUG_RT_MUTEXES
1149 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1150 depends on DEBUG_KERNEL && RT_MUTEXES
1151 help
1152 This allows rt mutex semantics violations and rt mutex related
1153 deadlocks (lockups) to be detected and reported automatically.
1154
1da177e4 1155config DEBUG_SPINLOCK
4d9f34ad 1156 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1157 depends on DEBUG_KERNEL
e335e3eb 1158 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1159 help
1160 Say Y here and build SMP to catch missing spinlock initialization
1161 and certain other kinds of spinlock errors commonly made. This is
1162 best used in conjunction with the NMI watchdog so that spinlock
1163 deadlocks are also debuggable.
1164
4d9f34ad
IM
1165config DEBUG_MUTEXES
1166 bool "Mutex debugging: basic checks"
1167 depends on DEBUG_KERNEL
1168 help
1169 This feature allows mutex semantics violations to be detected and
1170 reported.
1171
23010027
DV
1172config DEBUG_WW_MUTEX_SLOWPATH
1173 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1174 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1175 select DEBUG_LOCK_ALLOC
1176 select DEBUG_SPINLOCK
1177 select DEBUG_MUTEXES
1178 help
1179 This feature enables slowpath testing for w/w mutex users by
1180 injecting additional -EDEADLK wound/backoff cases. Together with
1181 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1182 will test all possible w/w mutex interface abuse with the
1183 exception of simply not acquiring all the required locks.
4d692373
RC
1184 Note that this feature can introduce significant overhead, so
1185 it really should not be enabled in a production or distro kernel,
1186 even a debug kernel. If you are a driver writer, enable it. If
1187 you are a distro, do not.
23010027 1188
5149cbac
WL
1189config DEBUG_RWSEMS
1190 bool "RW Semaphore debugging: basic checks"
c71fd893 1191 depends on DEBUG_KERNEL
5149cbac 1192 help
c71fd893
WL
1193 This debugging feature allows mismatched rw semaphore locks
1194 and unlocks to be detected and reported.
5149cbac 1195
4d9f34ad
IM
1196config DEBUG_LOCK_ALLOC
1197 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1198 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad
IM
1199 select DEBUG_SPINLOCK
1200 select DEBUG_MUTEXES
f5694788 1201 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1202 select LOCKDEP
1203 help
1204 This feature will check whether any held lock (spinlock, rwlock,
1205 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1206 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1207 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1208 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1209 held during task exit.
1210
4d9f34ad
IM
1211config LOCKDEP
1212 bool
f07cbebb 1213 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1214 select STACKTRACE
f9b58e8c 1215 select FRAME_POINTER if !MIPS && !PPC && !ARM && !S390 && !MICROBLAZE && !ARC && !X86
4d9f34ad
IM
1216 select KALLSYMS
1217 select KALLSYMS_ALL
1218
395102db
DJ
1219config LOCKDEP_SMALL
1220 bool
1221
4d9f34ad
IM
1222config DEBUG_LOCKDEP
1223 bool "Lock dependency engine debugging"
517e7aa5 1224 depends on DEBUG_KERNEL && LOCKDEP
4d9f34ad
IM
1225 help
1226 If you say Y here, the lock dependency engine will do
1227 additional runtime checks to debug itself, at the price
1228 of more runtime overhead.
1229
d902db1e
FW
1230config DEBUG_ATOMIC_SLEEP
1231 bool "Sleep inside atomic section checking"
e8f7c70f 1232 select PREEMPT_COUNT
1da177e4 1233 depends on DEBUG_KERNEL
87a4c375 1234 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1235 help
1236 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1237 noisy if they are called inside atomic sections: when a spinlock is
1238 held, inside an rcu read side critical section, inside preempt disabled
1239 sections, inside an interrupt, etc...
1da177e4 1240
cae2ed9a
IM
1241config DEBUG_LOCKING_API_SELFTESTS
1242 bool "Locking API boot-time self-tests"
1243 depends on DEBUG_KERNEL
1244 help
1245 Say Y here if you want the kernel to run a short self-test during
1246 bootup. The self-test checks whether common types of locking bugs
1247 are detected by debugging mechanisms or not. (if you disable
1248 lock debugging then those bugs wont be detected of course.)
1249 The following locking APIs are covered: spinlocks, rwlocks,
1250 mutexes and rwsems.
1251
0af3fe1e
PM
1252config LOCK_TORTURE_TEST
1253 tristate "torture tests for locking"
1254 depends on DEBUG_KERNEL
1255 select TORTURE_TEST
0af3fe1e
PM
1256 help
1257 This option provides a kernel module that runs torture tests
1258 on kernel locking primitives. The kernel module may be built
1259 after the fact on the running kernel to be tested, if desired.
1260
1261 Say Y here if you want kernel locking-primitive torture tests
1262 to be built into the kernel.
1263 Say M if you want these torture tests to build as a module.
1264 Say N if you are unsure.
1265
f2a5fec1
CW
1266config WW_MUTEX_SELFTEST
1267 tristate "Wait/wound mutex selftests"
1268 help
1269 This option provides a kernel module that runs tests on the
1270 on the struct ww_mutex locking API.
1271
1272 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1273 with this test harness.
1274
1275 Say M if you want these self tests to build as a module.
1276 Say N if you are unsure.
1277
9eade16b 1278endmenu # lock debugging
8637c099 1279
9eade16b
DH
1280config TRACE_IRQFLAGS
1281 bool
5ca43f6c 1282 help
9eade16b
DH
1283 Enables hooks to interrupt enabling and disabling for
1284 either tracing or lock debugging.
5ca43f6c 1285
8637c099 1286config STACKTRACE
0c38e1fe 1287 bool "Stack backtrace support"
8637c099 1288 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1289 help
1290 This option causes the kernel to create a /proc/pid/stack for
1291 every process, showing its current stack trace.
1292 It is also used by various kernel debugging features that require
1293 stack trace generation.
5ca43f6c 1294
eecabf56
TT
1295config WARN_ALL_UNSEEDED_RANDOM
1296 bool "Warn for all uses of unseeded randomness"
1297 default n
d06bfd19
JD
1298 help
1299 Some parts of the kernel contain bugs relating to their use of
1300 cryptographically secure random numbers before it's actually possible
1301 to generate those numbers securely. This setting ensures that these
1302 flaws don't go unnoticed, by enabling a message, should this ever
1303 occur. This will allow people with obscure setups to know when things
1304 are going wrong, so that they might contact developers about fixing
1305 it.
1306
eecabf56
TT
1307 Unfortunately, on some models of some architectures getting
1308 a fully seeded CRNG is extremely difficult, and so this can
1309 result in dmesg getting spammed for a surprisingly long
1310 time. This is really bad from a security perspective, and
1311 so architecture maintainers really need to do what they can
1312 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1313 However, since users cannot do anything actionable to
eecabf56
TT
1314 address this, by default the kernel will issue only a single
1315 warning for the first use of unseeded randomness.
1316
1317 Say Y here if you want to receive warnings for all uses of
1318 unseeded randomness. This will be of use primarily for
4c5d114e 1319 those developers interested in improving the security of
eecabf56
TT
1320 Linux kernels running on their architecture (or
1321 subarchitecture).
d06bfd19 1322
1da177e4
LT
1323config DEBUG_KOBJECT
1324 bool "kobject debugging"
1325 depends on DEBUG_KERNEL
1326 help
1327 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1328 to the syslog.
1da177e4 1329
c817a67e
RK
1330config DEBUG_KOBJECT_RELEASE
1331 bool "kobject release debugging"
2a999aa0 1332 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1333 help
1334 kobjects are reference counted objects. This means that their
1335 last reference count put is not predictable, and the kobject can
1336 live on past the point at which a driver decides to drop it's
1337 initial reference to the kobject gained on allocation. An
1338 example of this would be a struct device which has just been
1339 unregistered.
1340
1341 However, some buggy drivers assume that after such an operation,
1342 the memory backing the kobject can be immediately freed. This
1343 goes completely against the principles of a refcounted object.
1344
1345 If you say Y here, the kernel will delay the release of kobjects
1346 on the last reference count to improve the visibility of this
1347 kind of kobject release bug.
1348
9b2a60c4
CM
1349config HAVE_DEBUG_BUGVERBOSE
1350 bool
1351
1da177e4 1352config DEBUG_BUGVERBOSE
6a108a14 1353 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
9b2a60c4 1354 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
8420e7ef 1355 default y
1da177e4
LT
1356 help
1357 Say Y here to make BUG() panics output the file name and line number
1358 of the BUG call as well as the EIP and oops trace. This aids
1359 debugging but costs about 70-100K of memory.
1360
199a9afc
DJ
1361config DEBUG_LIST
1362 bool "Debug linked list manipulation"
4520bcb2 1363 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1364 help
1365 Enable this to turn on extended checks in the linked-list
1366 walking routines.
1367
1368 If unsure, say N.
1369
8e18faea 1370config DEBUG_PLIST
b8cfff68
DS
1371 bool "Debug priority linked list manipulation"
1372 depends on DEBUG_KERNEL
1373 help
1374 Enable this to turn on extended checks in the priority-ordered
1375 linked-list (plist) walking routines. This checks the entire
1376 list multiple times during each manipulation.
1377
1378 If unsure, say N.
1379
d6ec0842
JA
1380config DEBUG_SG
1381 bool "Debug SG table operations"
1382 depends on DEBUG_KERNEL
1383 help
1384 Enable this to turn on checks on scatter-gather tables. This can
1385 help find problems with drivers that do not properly initialize
1386 their sg tables.
1387
1388 If unsure, say N.
1389
1b2439db
AV
1390config DEBUG_NOTIFIERS
1391 bool "Debug notifier call chains"
1392 depends on DEBUG_KERNEL
1393 help
1394 Enable this to turn on sanity checking for notifier call chains.
1395 This is most useful for kernel developers to make sure that
1396 modules properly unregister themselves from notifier chains.
1397 This is a relatively cheap check but if you care about maximum
1398 performance, say N.
1399
e0e81739
DH
1400config DEBUG_CREDENTIALS
1401 bool "Debug credential management"
1402 depends on DEBUG_KERNEL
1403 help
1404 Enable this to turn on some debug checking for credential
1405 management. The additional code keeps track of the number of
1406 pointers from task_structs to any given cred struct, and checks to
1407 see that this number never exceeds the usage count of the cred
1408 struct.
1409
1410 Furthermore, if SELinux is enabled, this also checks that the
1411 security pointer in the cred struct is never seen to be invalid.
1412
1413 If unsure, say N.
1414
43a0a2a7 1415source "kernel/rcu/Kconfig.debug"
2f03e3ca 1416
f303fccb
TH
1417config DEBUG_WQ_FORCE_RR_CPU
1418 bool "Force round-robin CPU selection for unbound work items"
1419 depends on DEBUG_KERNEL
1420 default n
1421 help
1422 Workqueue used to implicitly guarantee that work items queued
1423 without explicit CPU specified are put on the local CPU. This
1424 guarantee is no longer true and while local CPU is still
1425 preferred work items may be put on foreign CPUs. Kernel
1426 parameter "workqueue.debug_force_rr_cpu" is added to force
1427 round-robin CPU selection to flush out usages which depend on the
1428 now broken guarantee. This config option enables the debug
1429 feature by default. When enabled, memory and cache locality will
1430 be impacted.
1431
870d6656
TH
1432config DEBUG_BLOCK_EXT_DEVT
1433 bool "Force extended block device numbers and spread them"
1434 depends on DEBUG_KERNEL
1435 depends on BLOCK
759f8ca3 1436 default n
870d6656 1437 help
0e11e342
TH
1438 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
1439 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
1440 YOU ARE DOING. Distros, please enable this and fix whatever
1441 is broken.
1442
870d6656
TH
1443 Conventionally, block device numbers are allocated from
1444 predetermined contiguous area. However, extended block area
1445 may introduce non-contiguous block device numbers. This
1446 option forces most block device numbers to be allocated from
1447 the extended space and spreads them to discover kernel or
1448 userland code paths which assume predetermined contiguous
1449 device number allocation.
1450
55dc7db7
TH
1451 Note that turning on this debug option shuffles all the
1452 device numbers for all IDE and SCSI devices including libata
1453 ones, so root partition specified using device number
1454 directly (via rdev or root=MAJ:MIN) won't work anymore.
1455 Textual device names (root=/dev/sdXn) will continue to work.
1456
870d6656
TH
1457 Say N if you are unsure.
1458
757c989b
TG
1459config CPU_HOTPLUG_STATE_CONTROL
1460 bool "Enable CPU hotplug state control"
1461 depends on DEBUG_KERNEL
1462 depends on HOTPLUG_CPU
1463 default n
1464 help
1465 Allows to write steps between "offline" and "online" to the CPUs
1466 sysfs target file so states can be stepped granular. This is a debug
1467 option for now as the hotplug machinery cannot be stopped and
1468 restarted at arbitrary points yet.
1469
1470 Say N if your are unsure.
1471
8d438288
AM
1472config NOTIFIER_ERROR_INJECTION
1473 tristate "Notifier error injection"
1474 depends on DEBUG_KERNEL
1475 select DEBUG_FS
1476 help
e41e85cc 1477 This option provides the ability to inject artificial errors to
8d438288
AM
1478 specified notifier chain callbacks. It is useful to test the error
1479 handling of notifier call chain failures.
1480
1481 Say N if unsure.
1482
048b9c35
AM
1483config PM_NOTIFIER_ERROR_INJECT
1484 tristate "PM notifier error injection module"
1485 depends on PM && NOTIFIER_ERROR_INJECTION
1486 default m if PM_DEBUG
1487 help
e41e85cc 1488 This option provides the ability to inject artificial errors to
048b9c35
AM
1489 PM notifier chain callbacks. It is controlled through debugfs
1490 interface /sys/kernel/debug/notifier-error-inject/pm
1491
1492 If the notifier call chain should be failed with some events
1493 notified, write the error code to "actions/<notifier event>/error".
1494
1495 Example: Inject PM suspend error (-12 = -ENOMEM)
1496
1497 # cd /sys/kernel/debug/notifier-error-inject/pm/
1498 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1499 # echo mem > /sys/power/state
1500 bash: echo: write error: Cannot allocate memory
1501
1502 To compile this code as a module, choose M here: the module will
1503 be called pm-notifier-error-inject.
1504
1505 If unsure, say N.
1506
d526e85f
BH
1507config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1508 tristate "OF reconfig notifier error injection module"
1509 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1510 help
e41e85cc 1511 This option provides the ability to inject artificial errors to
d526e85f 1512 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1513 through debugfs interface under
d526e85f 1514 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1515
1516 If the notifier call chain should be failed with some events
1517 notified, write the error code to "actions/<notifier event>/error".
1518
1519 To compile this code as a module, choose M here: the module will
e12a95f4 1520 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1521
1522 If unsure, say N.
1523
02fff96a
NA
1524config NETDEV_NOTIFIER_ERROR_INJECT
1525 tristate "Netdev notifier error injection module"
1526 depends on NET && NOTIFIER_ERROR_INJECTION
1527 help
1528 This option provides the ability to inject artificial errors to
1529 netdevice notifier chain callbacks. It is controlled through debugfs
1530 interface /sys/kernel/debug/notifier-error-inject/netdev
1531
1532 If the notifier call chain should be failed with some events
1533 notified, write the error code to "actions/<notifier event>/error".
1534
1535 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1536
1537 # cd /sys/kernel/debug/notifier-error-inject/netdev
1538 # echo -22 > actions/NETDEV_CHANGEMTU/error
1539 # ip link set eth0 mtu 1024
1540 RTNETLINK answers: Invalid argument
1541
1542 To compile this code as a module, choose M here: the module will
1543 be called netdev-notifier-error-inject.
1544
1545 If unsure, say N.
1546
f1b4bd06
MP
1547config FUNCTION_ERROR_INJECTION
1548 def_bool y
1549 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
1550
6ff1cb35 1551config FAULT_INJECTION
1ab8509a
AM
1552 bool "Fault-injection framework"
1553 depends on DEBUG_KERNEL
329409ae
AM
1554 help
1555 Provide fault-injection framework.
1556 For more details, see Documentation/fault-injection/.
6ff1cb35 1557
8a8b6502 1558config FAILSLAB
1ab8509a
AM
1559 bool "Fault-injection capability for kmalloc"
1560 depends on FAULT_INJECTION
773ff60e 1561 depends on SLAB || SLUB
8a8b6502 1562 help
1ab8509a 1563 Provide fault-injection capability for kmalloc.
8a8b6502 1564
933e312e
AM
1565config FAIL_PAGE_ALLOC
1566 bool "Fault-injection capabilitiy for alloc_pages()"
1ab8509a 1567 depends on FAULT_INJECTION
933e312e 1568 help
1ab8509a 1569 Provide fault-injection capability for alloc_pages().
933e312e 1570
c17bb495 1571config FAIL_MAKE_REQUEST
86327d19 1572 bool "Fault-injection capability for disk IO"
581d4e28 1573 depends on FAULT_INJECTION && BLOCK
c17bb495 1574 help
1ab8509a 1575 Provide fault-injection capability for disk IO.
c17bb495 1576
581d4e28 1577config FAIL_IO_TIMEOUT
f4d01439 1578 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1579 depends on FAULT_INJECTION && BLOCK
1580 help
1581 Provide fault-injection capability on end IO handling. This
1582 will make the block layer "forget" an interrupt as configured,
1583 thus exercising the error handling.
1584
1585 Only works with drivers that use the generic timeout handling,
1586 for others it wont do anything.
1587
ab51fbab
DB
1588config FAIL_FUTEX
1589 bool "Fault-injection capability for futexes"
1590 select DEBUG_FS
1591 depends on FAULT_INJECTION && FUTEX
1592 help
1593 Provide fault-injection capability for futexes.
1594
f1b4bd06
MP
1595config FAULT_INJECTION_DEBUG_FS
1596 bool "Debugfs entries for fault-injection capabilities"
1597 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1598 help
1599 Enable configuration of fault-injection capabilities via debugfs.
1600
4b1a29a7
MH
1601config FAIL_FUNCTION
1602 bool "Fault-injection capability for functions"
1603 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1604 help
1605 Provide function-based fault-injection capability.
1606 This will allow you to override a specific function with a return
1607 with given return value. As a result, function caller will see
1608 an error value and have to handle it. This is useful to test the
1609 error handling in various subsystems.
1610
f1b4bd06
MP
1611config FAIL_MMC_REQUEST
1612 bool "Fault-injection capability for MMC IO"
1613 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1614 help
f1b4bd06
MP
1615 Provide fault-injection capability for MMC IO.
1616 This will make the mmc core return data errors. This is
1617 useful to test the error handling in the mmc block device
1618 and to test how the mmc host driver handles retries from
1619 the block device.
1df49008
AM
1620
1621config FAULT_INJECTION_STACKTRACE_FILTER
1622 bool "stacktrace filter for fault-injection capabilities"
1623 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1624 depends on !X86_64
1df49008 1625 select STACKTRACE
f9b58e8c 1626 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
1df49008
AM
1627 help
1628 Provide stacktrace filter for fault-injection capabilities
267c4025 1629
9745512c
AV
1630config LATENCYTOP
1631 bool "Latency measuring infrastructure"
625fdcaa
RD
1632 depends on DEBUG_KERNEL
1633 depends on STACKTRACE_SUPPORT
1634 depends on PROC_FS
f9b58e8c 1635 select FRAME_POINTER if !MIPS && !PPC && !S390 && !MICROBLAZE && !ARM && !ARC && !X86
9745512c
AV
1636 select KALLSYMS
1637 select KALLSYMS_ALL
1638 select STACKTRACE
1639 select SCHEDSTATS
1640 select SCHED_DEBUG
9745512c
AV
1641 help
1642 Enable this option if you want to use the LatencyTOP tool
1643 to find out which userspace is blocking on what kernel operations.
1644
8636a1f9 1645source "kernel/trace/Kconfig"
16444a8a 1646
cc3fa840
RD
1647config PROVIDE_OHCI1394_DMA_INIT
1648 bool "Remote debugging over FireWire early on boot"
1649 depends on PCI && X86
1650 help
1651 If you want to debug problems which hang or crash the kernel early
1652 on boot and the crashing machine has a FireWire port, you can use
1653 this feature to remotely access the memory of the crashed machine
1654 over FireWire. This employs remote DMA as part of the OHCI1394
1655 specification which is now the standard for FireWire controllers.
1656
1657 With remote DMA, you can monitor the printk buffer remotely using
1658 firescope and access all memory below 4GB using fireproxy from gdb.
1659 Even controlling a kernel debugger is possible using remote DMA.
1660
1661 Usage:
1662
1663 If ohci1394_dma=early is used as boot parameter, it will initialize
1664 all OHCI1394 controllers which are found in the PCI config space.
1665
1666 As all changes to the FireWire bus such as enabling and disabling
1667 devices cause a bus reset and thereby disable remote DMA for all
1668 devices, be sure to have the cable plugged and FireWire enabled on
1669 the debugging host before booting the debug target for debugging.
1670
1671 This code (~1k) is freed after boot. By then, the firewire stack
1672 in charge of the OHCI-1394 controllers should be used instead.
1673
1674 See Documentation/debugging-via-ohci1394.txt for more information.
1675
84bc809e
BH
1676source "lib/kunit/Kconfig"
1677
d3deafaa
VL
1678menuconfig RUNTIME_TESTING_MENU
1679 bool "Runtime Testing"
908009e8 1680 def_bool y
d3deafaa
VL
1681
1682if RUNTIME_TESTING_MENU
881c5149
DH
1683
1684config LKDTM
1685 tristate "Linux Kernel Dump Test Tool Module"
1686 depends on DEBUG_FS
881c5149
DH
1687 help
1688 This module enables testing of the different dumping mechanisms by
1689 inducing system failures at predefined crash points.
1690 If you don't need it: say N
1691 Choose M here to compile this code as a module. The module will be
1692 called lkdtm.
1693
1694 Documentation on how to use the module can be found in
10ffebbe 1695 Documentation/fault-injection/provoke-crashes.rst
881c5149
DH
1696
1697config TEST_LIST_SORT
e327fd7c
GU
1698 tristate "Linked list sorting test"
1699 depends on DEBUG_KERNEL || m
881c5149
DH
1700 help
1701 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
1702 executed only once during system boot (so affects only boot time),
1703 or at module load time.
881c5149
DH
1704
1705 If unsure, say N.
1706
c5adae95 1707config TEST_SORT
5c4e6798
GU
1708 tristate "Array-based sort test"
1709 depends on DEBUG_KERNEL || m
c5adae95 1710 help
5c4e6798
GU
1711 This option enables the self-test function of 'sort()' at boot,
1712 or at module load time.
c5adae95
KF
1713
1714 If unsure, say N.
1715
881c5149
DH
1716config KPROBES_SANITY_TEST
1717 bool "Kprobes sanity tests"
1718 depends on DEBUG_KERNEL
1719 depends on KPROBES
881c5149
DH
1720 help
1721 This option provides for testing basic kprobes functionality on
5a6cf77f 1722 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
1723 verified for functionality.
1724
1725 Say N if you are unsure.
1726
1727config BACKTRACE_SELF_TEST
1728 tristate "Self test for the backtrace code"
1729 depends on DEBUG_KERNEL
881c5149
DH
1730 help
1731 This option provides a kernel module that can be used to test
1732 the kernel stack backtrace code. This option is not useful
1733 for distributions or general kernels, but only for kernel
1734 developers working on architecture code.
1735
1736 Note that if you want to also test saved backtraces, you will
1737 have to enable STACKTRACE as well.
1738
1739 Say N if you are unsure.
1740
910a742d
ML
1741config RBTREE_TEST
1742 tristate "Red-Black tree test"
7c993e11 1743 depends on DEBUG_KERNEL
910a742d
ML
1744 help
1745 A benchmark measuring the performance of the rbtree library.
1746 Also includes rbtree invariant checks.
1747
4b4f3acc
FB
1748config REED_SOLOMON_TEST
1749 tristate "Reed-Solomon library test"
1750 depends on DEBUG_KERNEL || m
1751 select REED_SOLOMON
1752 select REED_SOLOMON_ENC16
1753 select REED_SOLOMON_DEC16
1754 help
1755 This option enables the self-test function of rslib at boot,
1756 or at module load time.
1757
1758 If unsure, say N.
1759
fff3fd8a
ML
1760config INTERVAL_TREE_TEST
1761 tristate "Interval tree test"
0f789b67 1762 depends on DEBUG_KERNEL
a88cc108 1763 select INTERVAL_TREE
fff3fd8a
ML
1764 help
1765 A benchmark measuring the performance of the interval tree library
1766
623fd807
GT
1767config PERCPU_TEST
1768 tristate "Per cpu operations test"
1769 depends on m && DEBUG_KERNEL
1770 help
1771 Enable this option to build test module which validates per-cpu
1772 operations.
1773
1774 If unsure, say N.
1775
881c5149 1776config ATOMIC64_SELFTEST
55ded955 1777 tristate "Perform an atomic64_t self-test"
881c5149 1778 help
55ded955
GU
1779 Enable this option to test the atomic64_t functions at boot or
1780 at module load time.
881c5149
DH
1781
1782 If unsure, say N.
1783
1784config ASYNC_RAID6_TEST
1785 tristate "Self test for hardware accelerated raid6 recovery"
1786 depends on ASYNC_RAID6_RECOV
1787 select ASYNC_MEMCPY
1788 ---help---
1789 This is a one-shot self test that permutes through the
1790 recovery of all the possible two disk failure scenarios for a
1791 N-disk array. Recovery is performed with the asynchronous
1792 raid6 recovery routines, and will optionally use an offload
1793 engine if one is available.
1794
1795 If unsure, say N.
1796
64d1d77a
AS
1797config TEST_HEXDUMP
1798 tristate "Test functions located in the hexdump module at runtime"
1799
881c5149
DH
1800config TEST_STRING_HELPERS
1801 tristate "Test functions located in the string_helpers module at runtime"
1802
0b0600c8
TH
1803config TEST_STRSCPY
1804 tristate "Test strscpy*() family of functions at runtime"
1805
881c5149
DH
1806config TEST_KSTRTOX
1807 tristate "Test kstrto*() family of functions at runtime"
1808
707cc728
RV
1809config TEST_PRINTF
1810 tristate "Test printf() family of functions at runtime"
1811
5fd003f5
DD
1812config TEST_BITMAP
1813 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
1814 help
1815 Enable this option to test the bitmap functions at boot.
1816
1817 If unsure, say N.
1818
0e2dc70e
JB
1819config TEST_BITFIELD
1820 tristate "Test bitfield functions at runtime"
1821 help
1822 Enable this option to test the bitfield functions at boot.
1823
1824 If unsure, say N.
1825
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AS
1826config TEST_UUID
1827 tristate "Test functions located in the uuid module at runtime"
1828
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MW
1829config TEST_XARRAY
1830 tristate "Test the XArray code at runtime"
1831
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RV
1832config TEST_OVERFLOW
1833 tristate "Test check_*_overflow() functions at runtime"
1834
7e1e7763 1835config TEST_RHASHTABLE
9d6dbe1b 1836 tristate "Perform selftest on resizable hash table"
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TG
1837 help
1838 Enable this option to test the rhashtable functions at boot.
1839
1840 If unsure, say N.
1841
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GS
1842config TEST_HASH
1843 tristate "Perform selftest on hash functions"
468a9428 1844 help
2c956a60
JD
1845 Enable this option to test the kernel's integer (<linux/hash.h>),
1846 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
1847 hash functions on boot (or module load).
468a9428
GS
1848
1849 This is intended to help people writing architecture-specific
1850 optimized versions. If unsure, say N.
1851
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MW
1852config TEST_IDA
1853 tristate "Perform selftest on IDA functions"
1854
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JP
1855config TEST_PARMAN
1856 tristate "Perform selftest on priority array manager"
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JP
1857 depends on PARMAN
1858 help
1859 Enable this option to test priority array manager on boot
1860 (or module load).
1861
1862 If unsure, say N.
1863
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DL
1864config TEST_IRQ_TIMINGS
1865 bool "IRQ timings selftest"
1866 depends on IRQ_TIMINGS
1867 help
1868 Enable this option to test the irq timings code on boot.
1869
1870 If unsure, say N.
1871
8a6f0b47 1872config TEST_LKM
93e9ef83 1873 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
1874 depends on m
1875 help
1876 This builds the "test_module" module that emits "Hello, world"
1877 on printk when loaded. It is designed to be used for basic
1878 evaluation of the module loading subsystem (for example when
1879 validating module verification). It lacks any extra dependencies,
1880 and will not normally be loaded by the system unless explicitly
1881 requested by name.
1882
1883 If unsure, say N.
1884
3f21a6b7
URS
1885config TEST_VMALLOC
1886 tristate "Test module for stress/performance analysis of vmalloc allocator"
1887 default n
1888 depends on MMU
1889 depends on m
1890 help
1891 This builds the "test_vmalloc" module that should be used for
1892 stress and performance analysis. So, any new change for vmalloc
1893 subsystem can be evaluated from performance and stability point
1894 of view.
1895
1896 If unsure, say N.
1897
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KC
1898config TEST_USER_COPY
1899 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
1900 depends on m
1901 help
1902 This builds the "test_user_copy" module that runs sanity checks
1903 on the copy_to/from_user infrastructure, making sure basic
1904 user/kernel boundary testing is working. If it fails to load,
1905 a regression has been detected in the user/kernel memory boundary
1906 protections.
1907
1908 If unsure, say N.
1909
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AS
1910config TEST_BPF
1911 tristate "Test BPF filter functionality"
98920ba6 1912 depends on m && NET
64a8946b
AS
1913 help
1914 This builds the "test_bpf" module that runs various test vectors
1915 against the BPF interpreter or BPF JIT compiler depending on the
1916 current setting. This is in particular useful for BPF JIT compiler
1917 development, but also to run regression tests against changes in
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AS
1918 the interpreter code. It also enables test stubs for eBPF maps and
1919 verifier used by user space verifier testsuite.
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AS
1920
1921 If unsure, say N.
1922
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MB
1923config TEST_BLACKHOLE_DEV
1924 tristate "Test blackhole netdev functionality"
1925 depends on m && NET
1926 help
1927 This builds the "test_blackhole_dev" module that validates the
1928 data path through this blackhole netdev.
1929
1930 If unsure, say N.
1931
dceeb3e7 1932config FIND_BIT_BENCHMARK
4441fca0 1933 tristate "Test find_bit functions"
4441fca0
YN
1934 help
1935 This builds the "test_find_bit" module that measure find_*_bit()
1936 functions performance.
1937
1938 If unsure, say N.
1939
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KC
1940config TEST_FIRMWARE
1941 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
1942 depends on FW_LOADER
1943 help
1944 This builds the "test_firmware" module that creates a userspace
1945 interface for testing firmware loading. This can be used to
1946 control the triggering of firmware loading without needing an
1947 actual firmware-using device. The contents can be rechecked by
1948 userspace.
1949
1950 If unsure, say N.
1951
9308f2f9
LR
1952config TEST_SYSCTL
1953 tristate "sysctl test driver"
9308f2f9
LR
1954 depends on PROC_SYSCTL
1955 help
1956 This builds the "test_sysctl" module. This driver enables to test the
1957 proc sysctl interfaces available to drivers safely without affecting
1958 production knobs which might alter system functionality.
1959
1960 If unsure, say N.
1961
2cb80dbb
IZ
1962config SYSCTL_KUNIT_TEST
1963 bool "KUnit test for sysctl"
1964 depends on KUNIT
1965 help
1966 This builds the proc sysctl unit test, which runs on boot.
1967 Tests the API contract and implementation correctness of sysctl.
1968 For more information on KUnit and unit tests in general please refer
1969 to the KUnit documentation in Documentation/dev-tools/kunit/.
1970
1971 If unsure, say N.
1972
ea2dd7c0
DG
1973config LIST_KUNIT_TEST
1974 bool "KUnit Test for Kernel Linked-list structures"
1975 depends on KUNIT
1976 help
1977 This builds the linked list KUnit test suite.
1978 It tests that the API and basic functionality of the list_head type
1979 and associated macros.
1980
1981 KUnit tests run during boot and output the results to the debug log
1982 in TAP format (http://testanything.org/). Only useful for kernel devs
1983 running the KUnit test harness, and not intended for inclusion into a
1984 production build.
1985
1986 For more information on KUnit and unit tests in general please refer
1987 to the KUnit documentation in Documentation/dev-tools/kunit/.
1988
1989 If unsure, say N.
1990
e704f93a
DR
1991config TEST_UDELAY
1992 tristate "udelay test driver"
e704f93a
DR
1993 help
1994 This builds the "udelay_test" module that helps to make sure
1995 that udelay() is working properly.
1996
1997 If unsure, say N.
1998
2bf9e0ab
IM
1999config TEST_STATIC_KEYS
2000 tristate "Test static keys"
579e1acb
JB
2001 depends on m
2002 help
2bf9e0ab 2003 Test the static key interfaces.
579e1acb
JB
2004
2005 If unsure, say N.
2006
d9c6a72d
LR
2007config TEST_KMOD
2008 tristate "kmod stress tester"
d9c6a72d 2009 depends on m
d9c6a72d 2010 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2011 depends on BLOCK
d9c6a72d
LR
2012 select TEST_LKM
2013 select XFS_FS
2014 select TUN
2015 select BTRFS_FS
2016 help
2017 Test the kernel's module loading mechanism: kmod. kmod implements
2018 support to load modules using the Linux kernel's usermode helper.
2019 This test provides a series of tests against kmod.
2020
2021 Although technically you can either build test_kmod as a module or
2022 into the kernel we disallow building it into the kernel since
2023 it stress tests request_module() and this will very likely cause
2024 some issues by taking over precious threads available from other
2025 module load requests, ultimately this could be fatal.
2026
2027 To run tests run:
2028
2029 tools/testing/selftests/kmod/kmod.sh --help
2030
2031 If unsure, say N.
2032
e4dace36
FF
2033config TEST_DEBUG_VIRTUAL
2034 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2035 depends on DEBUG_VIRTUAL
2036 help
2037 Test the kernel's ability to detect incorrect calls to
2038 virt_to_phys() done against the non-linear part of the
2039 kernel's virtual address map.
2040
2041 If unsure, say N.
2042
ce76d938
AS
2043config TEST_MEMCAT_P
2044 tristate "Test memcat_p() helper function"
2045 help
2046 Test the memcat_p() helper for correctly merging two
2047 pointer arrays together.
2048
2049 If unsure, say N.
2050
a2818ee4
JL
2051config TEST_LIVEPATCH
2052 tristate "Test livepatching"
2053 default n
bae05437 2054 depends on DYNAMIC_DEBUG
a2818ee4
JL
2055 depends on LIVEPATCH
2056 depends on m
2057 help
2058 Test kernel livepatching features for correctness. The tests will
2059 load test modules that will be livepatched in various scenarios.
2060
2061 To run all the livepatching tests:
2062
2063 make -C tools/testing/selftests TARGETS=livepatch run_tests
2064
2065 Alternatively, individual tests may be invoked:
2066
2067 tools/testing/selftests/livepatch/test-callbacks.sh
2068 tools/testing/selftests/livepatch/test-livepatch.sh
2069 tools/testing/selftests/livepatch/test-shadow-vars.sh
2070
2071 If unsure, say N.
2072
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JP
2073config TEST_OBJAGG
2074 tristate "Perform selftest on object aggreration manager"
2075 default n
2076 depends on OBJAGG
2077 help
2078 Enable this option to test object aggregation manager on boot
2079 (or module load).
2080
0a020d41 2081
50ceaa95
KC
2082config TEST_STACKINIT
2083 tristate "Test level of stack variable initialization"
2084 help
2085 Test if the kernel is zero-initializing stack variables and
2086 padding. Coverage is controlled by compiler flags,
2087 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2088 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2089
2090 If unsure, say N.
2091
5015a300
AP
2092config TEST_MEMINIT
2093 tristate "Test heap/page initialization"
2094 help
2095 Test if the kernel is zero-initializing heap and page allocations.
2096 This can be useful to test init_on_alloc and init_on_free features.
2097
2098 If unsure, say N.
2099
d3deafaa 2100endif # RUNTIME_TESTING_MENU
cc3fa840
RD
2101
2102config MEMTEST
2103 bool "Memtest"
cc3fa840
RD
2104 ---help---
2105 This option adds a kernel parameter 'memtest', which allows memtest
2106 to be set.
2107 memtest=0, mean disabled; -- default
2108 memtest=1, mean do 1 test pattern;
2109 ...
2110 memtest=17, mean do 17 test patterns.
2111 If you are unsure how to answer this question, answer N.
2112
2113config BUG_ON_DATA_CORRUPTION
2114 bool "Trigger a BUG when data corruption is detected"
2115 select DEBUG_LIST
2116 help
2117 Select this option if the kernel should BUG when it encounters
2118 data corruption in kernel memory structures when they get checked
2119 for validity.
2120
2121 If unsure, say N.
e4dace36 2122
267c4025 2123source "samples/Kconfig"
dc7d5527
JW
2124
2125source "lib/Kconfig.kgdb"
0a4af3b0 2126
c6d30853
AR
2127source "lib/Kconfig.ubsan"
2128
21266be9
DW
2129config ARCH_HAS_DEVMEM_IS_ALLOWED
2130 bool
2131
2132config STRICT_DEVMEM
2133 bool "Filter access to /dev/mem"
6b2a65c7 2134 depends on MMU && DEVMEM
21266be9 2135 depends on ARCH_HAS_DEVMEM_IS_ALLOWED
a687a533 2136 default y if PPC || X86 || ARM64
21266be9
DW
2137 ---help---
2138 If this option is disabled, you allow userspace (root) access to all
2139 of memory, including kernel and userspace memory. Accidental
2140 access to this is obviously disastrous, but specific access can
2141 be used by people debugging the kernel. Note that with PAT support
2142 enabled, even in this case there are restrictions on /dev/mem
2143 use due to the cache aliasing requirements.
2144
90a545e9
DW
2145 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
2146 file only allows userspace access to PCI space and the BIOS code and
2147 data regions. This is sufficient for dosemu and X and all common
2148 users of /dev/mem.
2149
2150 If in doubt, say Y.
2151
2152config IO_STRICT_DEVMEM
2153 bool "Filter I/O access to /dev/mem"
2154 depends on STRICT_DEVMEM
90a545e9
DW
2155 ---help---
2156 If this option is disabled, you allow userspace (root) access to all
2157 io-memory regardless of whether a driver is actively using that
2158 range. Accidental access to this is obviously disastrous, but
2159 specific access can be used by people debugging kernel drivers.
2160
21266be9 2161 If this option is switched on, the /dev/mem file only allows
90a545e9
DW
2162 userspace access to *idle* io-memory ranges (see /proc/iomem) This
2163 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
2164 if the driver using a given range cannot be disabled.
21266be9
DW
2165
2166 If in doubt, say Y.
06ec64b8
CH
2167
2168source "arch/$(SRCARCH)/Kconfig.debug"
2169
af9ca6f9
BB
2170config HYPERV_TESTING
2171 bool "Microsoft Hyper-V driver testing"
2172 default n
2173 depends on HYPERV && DEBUG_FS
2174 help
2175 Select this option to enable Hyper-V vmbus testing.
2176
06ec64b8 2177endmenu # Kernel hacking