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ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
06ec64b8
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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 STACKTRACE_BUILD_ID
39 bool "Show build ID information in stacktraces"
40 depends on PRINTK
41 help
42 Selecting this option adds build ID information for symbols in
43 stacktraces printed with the printk format '%p[SR]b'.
44
45 This option is intended for distros where debuginfo is not easily
46 accessible but can be downloaded given the build ID of the vmlinux or
47 kernel module where the function is located.
48
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49config CONSOLE_LOGLEVEL_DEFAULT
50 int "Default console loglevel (1-15)"
51 range 1 15
52 default "7"
53 help
54 Default loglevel to determine what will be printed on the console.
55
56 Setting a default here is equivalent to passing in loglevel=<x> in
57 the kernel bootargs. loglevel=<x> continues to override whatever
58 value is specified here as well.
59
50f4d9bd 60 Note: This does not affect the log level of un-prefixed printk()
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61 usage in the kernel. That is controlled by the MESSAGE_LOGLEVEL_DEFAULT
62 option.
63
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64config CONSOLE_LOGLEVEL_QUIET
65 int "quiet console loglevel (1-15)"
66 range 1 15
67 default "4"
68 help
69 loglevel to use when "quiet" is passed on the kernel commandline.
70
71 When "quiet" is passed on the kernel commandline this loglevel
72 will be used as the loglevel. IOW passing "quiet" will be the
73 equivalent of passing "loglevel=<CONSOLE_LOGLEVEL_QUIET>"
74
42a9dc0b 75config MESSAGE_LOGLEVEL_DEFAULT
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76 int "Default message log level (1-7)"
77 range 1 7
78 default "4"
79 help
80 Default log level for printk statements with no specified priority.
81
82 This was hard-coded to KERN_WARNING since at least 2.6.10 but folks
83 that are auditing their logs closely may want to set it to a lower
84 priority.
85
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86 Note: This does not affect what message level gets printed on the console
87 by default. To change that, use loglevel=<x> in the kernel bootargs,
88 or pick a different CONSOLE_LOGLEVEL_DEFAULT configuration value.
89
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90config BOOT_PRINTK_DELAY
91 bool "Delay each boot printk message by N milliseconds"
92 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
93 help
94 This build option allows you to read kernel boot messages
95 by inserting a short delay after each one. The delay is
96 specified in milliseconds on the kernel command line,
97 using "boot_delay=N".
98
99 It is likely that you would also need to use "lpj=M" to preset
100 the "loops per jiffie" value.
101 See a previous boot log for the "lpj" value to use for your
102 system, and then set "lpj=M" before setting "boot_delay=N".
103 NOTE: Using this option may adversely affect SMP systems.
104 I.e., processors other than the first one may not boot up.
105 BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
106 what it believes to be lockup conditions.
107
108config DYNAMIC_DEBUG
109 bool "Enable dynamic printk() support"
110 default n
111 depends on PRINTK
239a5791 112 depends on (DEBUG_FS || PROC_FS)
ceabef7d 113 select DYNAMIC_DEBUG_CORE
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114 help
115
116 Compiles debug level messages into the kernel, which would not
117 otherwise be available at runtime. These messages can then be
118 enabled/disabled based on various levels of scope - per source file,
119 function, module, format string, and line number. This mechanism
120 implicitly compiles in all pr_debug() and dev_dbg() calls, which
121 enlarges the kernel text size by about 2%.
122
123 If a source file is compiled with DEBUG flag set, any
124 pr_debug() calls in it are enabled by default, but can be
125 disabled at runtime as below. Note that DEBUG flag is
126 turned on by many CONFIG_*DEBUG* options.
127
128 Usage:
129
130 Dynamic debugging is controlled via the 'dynamic_debug/control' file,
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131 which is contained in the 'debugfs' filesystem or procfs.
132 Thus, the debugfs or procfs filesystem must first be mounted before
133 making use of this feature.
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134 We refer the control file as: <debugfs>/dynamic_debug/control. This
135 file contains a list of the debug statements that can be enabled. The
136 format for each line of the file is:
137
138 filename:lineno [module]function flags format
139
140 filename : source file of the debug statement
141 lineno : line number of the debug statement
142 module : module that contains the debug statement
143 function : function that contains the debug statement
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144 flags : '=p' means the line is turned 'on' for printing
145 format : the format used for the debug statement
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146
147 From a live system:
148
149 nullarbor:~ # cat <debugfs>/dynamic_debug/control
150 # filename:lineno [module]function flags format
151 fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
152 fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
153 fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
154
155 Example usage:
156
157 // enable the message at line 1603 of file svcsock.c
158 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
159 <debugfs>/dynamic_debug/control
160
161 // enable all the messages in file svcsock.c
162 nullarbor:~ # echo -n 'file svcsock.c +p' >
163 <debugfs>/dynamic_debug/control
164
165 // enable all the messages in the NFS server module
166 nullarbor:~ # echo -n 'module nfsd +p' >
167 <debugfs>/dynamic_debug/control
168
169 // enable all 12 messages in the function svc_process()
170 nullarbor:~ # echo -n 'func svc_process +p' >
171 <debugfs>/dynamic_debug/control
172
173 // disable all 12 messages in the function svc_process()
174 nullarbor:~ # echo -n 'func svc_process -p' >
175 <debugfs>/dynamic_debug/control
176
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177 See Documentation/admin-guide/dynamic-debug-howto.rst for additional
178 information.
604ff0dc 179
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180config DYNAMIC_DEBUG_CORE
181 bool "Enable core function of dynamic debug support"
182 depends on PRINTK
183 depends on (DEBUG_FS || PROC_FS)
184 help
185 Enable core functional support of dynamic debug. It is useful
186 when you want to tie dynamic debug to your kernel modules with
187 DYNAMIC_DEBUG_MODULE defined for each of them, especially for
188 the case of embedded system where the kernel image size is
189 sensitive for people.
190
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191config SYMBOLIC_ERRNAME
192 bool "Support symbolic error names in printf"
193 default y if PRINTK
194 help
195 If you say Y here, the kernel's printf implementation will
196 be able to print symbolic error names such as ENOSPC instead
197 of the number 28. It makes the kernel image slightly larger
198 (about 3KB), but can make the kernel logs easier to read.
199
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200config DEBUG_BUGVERBOSE
201 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EXPERT
202 depends on BUG && (GENERIC_BUG || HAVE_DEBUG_BUGVERBOSE)
203 default y
204 help
205 Say Y here to make BUG() panics output the file name and line number
206 of the BUG call as well as the EIP and oops trace. This aids
207 debugging but costs about 70-100K of memory.
208
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209endmenu # "printk and dmesg options"
210
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211# Clang is known to generate .{s,u}leb128 with symbol deltas with DWARF5, which
212# some targets may not support: https://sourceware.org/bugzilla/show_bug.cgi?id=27215
213config AS_HAS_NON_CONST_LEB128
214 def_bool $(as-instr,.uleb128 .Lexpr_end4 - .Lexpr_start3\n.Lexpr_start3:\n.Lexpr_end4:)
215
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216menu "Compile-time checks and compiler options"
217
218config DEBUG_INFO
219 bool "Compile the kernel with debug info"
12b13835 220 depends on DEBUG_KERNEL && !COMPILE_TEST
6dfc0665 221 help
68d4b3df 222 If you say Y here the resulting kernel image will include
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223 debugging info resulting in a larger kernel image.
224 This adds debug symbols to the kernel and modules (gcc -g), and
225 is needed if you intend to use kernel crashdump or binary object
226 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
227 Say Y here only if you plan to debug the kernel.
228
229 If unsure, say N.
230
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231if DEBUG_INFO
232
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233config DEBUG_INFO_REDUCED
234 bool "Reduce debugging information"
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235 help
236 If you say Y here gcc is instructed to generate less debugging
237 information for structure types. This means that tools that
238 need full debugging information (like kgdb or systemtap) won't
239 be happy. But if you merely need debugging information to
240 resolve line numbers there is no loss. Advantage is that
241 build directory object sizes shrink dramatically over a full
242 DEBUG_INFO build and compile times are reduced too.
243 Only works with newer gcc versions.
244
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245config DEBUG_INFO_COMPRESSED
246 bool "Compressed debugging information"
10e68b02 247 depends on $(cc-option,-gz=zlib)
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248 depends on $(ld-option,--compress-debug-sections=zlib)
249 help
250 Compress the debug information using zlib. Requires GCC 5.0+ or Clang
251 5.0+, binutils 2.26+, and zlib.
252
253 Users of dpkg-deb via scripts/package/builddeb may find an increase in
254 size of their debug .deb packages with this config set, due to the
255 debug info being compressed with zlib, then the object files being
256 recompressed with a different compression scheme. But this is still
257 preferable to setting $KDEB_COMPRESS to "none" which would be even
258 larger.
259
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260config DEBUG_INFO_SPLIT
261 bool "Produce split debuginfo in .dwo files"
9d937444 262 depends on $(cc-option,-gsplit-dwarf)
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263 help
264 Generate debug info into separate .dwo files. This significantly
265 reduces the build directory size for builds with DEBUG_INFO,
266 because it stores the information only once on disk in .dwo
267 files instead of multiple times in object files and executables.
268 In addition the debug information is also compressed.
269
270 Requires recent gcc (4.7+) and recent gdb/binutils.
271 Any tool that packages or reads debug information would need
272 to know about the .dwo files and include them.
273 Incompatible with older versions of ccache.
274
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275choice
276 prompt "DWARF version"
277 help
278 Which version of DWARF debug info to emit.
279
280config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
281 bool "Rely on the toolchain's implicit default DWARF version"
6b91ef64 282 depends on !CC_IS_CLANG || AS_IS_LLVM || CLANG_VERSION < 140000 || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
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283 help
284 The implicit default version of DWARF debug info produced by a
285 toolchain changes over time.
286
287 This can break consumers of the debug info that haven't upgraded to
288 support newer revisions, and prevent testing newer versions, but
289 those should be less common scenarios.
290
291 If unsure, say Y.
292
bfaf2dd3 293config DEBUG_INFO_DWARF4
a66049e2 294 bool "Generate DWARF Version 4 debuginfo"
bfaf2dd3 295 help
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ND
296 Generate DWARF v4 debug info. This requires gcc 4.5+ and gdb 7.0+.
297
298 If you have consumers of DWARF debug info that are not ready for
299 newer revisions of DWARF, you may wish to choose this or have your
300 config select this.
301
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302config DEBUG_INFO_DWARF5
303 bool "Generate DWARF Version 5 debuginfo"
6b91ef64 304 depends on !CC_IS_CLANG || AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502 && AS_HAS_NON_CONST_LEB128)
96858bf6 305 depends on !DEBUG_INFO_BTF || PAHOLE_VERSION >= 121
bfaf2dd3 306 help
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307 Generate DWARF v5 debug info. Requires binutils 2.35.2, gcc 5.0+ (gcc
308 5.0+ accepts the -gdwarf-5 flag but only had partial support for some
309 draft features until 7.0), and gdb 8.0+.
310
311 Changes to the structure of debug info in Version 5 allow for around
312 15-18% savings in resulting image and debug info section sizes as
313 compared to DWARF Version 4. DWARF Version 5 standardizes previous
314 extensions such as accelerators for symbol indexing and the format
315 for fission (.dwo/.dwp) files. Users may not want to select this
316 config if they rely on tooling that has not yet been updated to
317 support DWARF Version 5.
318
a66049e2 319endchoice # "DWARF version"
bfaf2dd3 320
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321config DEBUG_INFO_BTF
322 bool "Generate BTF typeinfo"
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323 depends on !DEBUG_INFO_SPLIT && !DEBUG_INFO_REDUCED
324 depends on !GCC_PLUGIN_RANDSTRUCT || COMPILE_TEST
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325 help
326 Generate deduplicated BTF type information from DWARF debug info.
327 Turning this on expects presence of pahole tool, which will convert
328 DWARF type info into equivalent deduplicated BTF type info.
329
5f9ae91f 330config PAHOLE_HAS_SPLIT_BTF
cfa84bb8 331 def_bool PAHOLE_VERSION >= 119
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332
333config DEBUG_INFO_BTF_MODULES
334 def_bool y
335 depends on DEBUG_INFO_BTF && MODULES && PAHOLE_HAS_SPLIT_BTF
336 help
337 Generate compact split BTF type information for kernel modules.
338
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339config GDB_SCRIPTS
340 bool "Provide GDB scripts for kernel debugging"
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341 help
342 This creates the required links to GDB helper scripts in the
343 build directory. If you load vmlinux into gdb, the helper
344 scripts will be automatically imported by gdb as well, and
345 additional functions are available to analyze a Linux kernel
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346 instance. See Documentation/dev-tools/gdb-kernel-debugging.rst
347 for further details.
3ee7b3fa 348
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349endif # DEBUG_INFO
350
35bb5b1e 351config FRAME_WARN
a83e4ca2 352 int "Warn for stack frames larger than"
35bb5b1e 353 range 0 8192
0e07f663 354 default 2048 if GCC_PLUGIN_LATENT_ENTROPY
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355 default 2048 if PARISC
356 default 1536 if (!64BIT && XTENSA)
5db37aa6 357 default 1280 if KASAN && !64BIT
8c774a0d 358 default 1024 if !64BIT
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359 default 2048 if 64BIT
360 help
361 Tell gcc to warn at build time for stack frames larger than this.
362 Setting this too low will cause a lot of warnings.
363 Setting it to 0 disables the warning.
35bb5b1e 364
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365config STRIP_ASM_SYMS
366 bool "Strip assembler-generated symbols during link"
367 default n
368 help
369 Strip internal assembler-generated symbols during a link (symbols
370 that look like '.Lxxx') so they don't pollute the output of
371 get_wchan() and suchlike.
372
1873e870 373config READABLE_ASM
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374 bool "Generate readable assembler code"
375 depends on DEBUG_KERNEL
7d73c3e9 376 depends on CC_IS_GCC
bf4735a4 377 help
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378 Disable some compiler optimizations that tend to generate human unreadable
379 assembler output. This may make the kernel slightly slower, but it helps
380 to keep kernel developers who have to stare a lot at assembler listings
381 sane.
bf4735a4 382
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383config HEADERS_INSTALL
384 bool "Install uapi headers to usr/include"
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385 depends on !UML
386 help
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387 This option will install uapi headers (headers exported to user-space)
388 into the usr/include directory for use during the kernel build.
389 This is unneeded for building the kernel itself, but needed for some
390 user-space program samples. It is also needed by some features such
391 as uapi header sanity checks.
392
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393config DEBUG_SECTION_MISMATCH
394 bool "Enable full Section mismatch analysis"
7d73c3e9 395 depends on CC_IS_GCC
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396 help
397 The section mismatch analysis checks if there are illegal
398 references from one section to another section.
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399 During linktime or runtime, some sections are dropped;
400 any use of code/data previously in these sections would
91341d4b 401 most likely result in an oops.
e809ab01 402 In the code, functions and variables are annotated with
0db0628d 403 __init,, etc. (see the full list in include/linux/init.h),
d6fbfa4f 404 which results in the code/data being placed in specific sections.
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405 The section mismatch analysis is always performed after a full
406 kernel build, and enabling this option causes the following
b7dca6dd 407 additional step to occur:
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408 - Add the option -fno-inline-functions-called-once to gcc commands.
409 When inlining a function annotated with __init in a non-init
410 function, we would lose the section information and thus
91341d4b 411 the analysis would not catch the illegal reference.
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412 This option tells gcc to inline less (but it does result in
413 a larger kernel).
91341d4b 414
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415config SECTION_MISMATCH_WARN_ONLY
416 bool "Make section mismatch errors non-fatal"
417 default y
418 help
419 If you say N here, the build process will fail if there are any
420 section mismatch, instead of just throwing warnings.
421
422 If unsure, say Y.
423
cf536e18 424config DEBUG_FORCE_FUNCTION_ALIGN_64B
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425 bool "Force all function address 64B aligned"
426 depends on EXPERT && (X86_64 || ARM64 || PPC32 || PPC64 || ARC)
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427 help
428 There are cases that a commit from one domain changes the function
429 address alignment of other domains, and cause magic performance
430 bump (regression or improvement). Enable this option will help to
431 verify if the bump is caused by function alignment changes, while
432 it will slightly increase the kernel size and affect icache usage.
433
434 It is mainly for debug and performance tuning use.
435
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436#
437# Select this config option from the architecture Kconfig, if it
438# is preferred to always offer frame pointers as a config
439# option on the architecture (regardless of KERNEL_DEBUG):
440#
441config ARCH_WANT_FRAME_POINTERS
442 bool
f346f4b3 443
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444config FRAME_POINTER
445 bool "Compile the kernel with frame pointers"
a687a533 446 depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS
6dfc0665 447 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
a304e1b8 448 help
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449 If you say Y here the resulting kernel image will be slightly
450 larger and slower, but it gives very useful debugging information
451 in case of kernel bugs. (precise oopses/stacktraces/warnings)
a304e1b8 452
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453config STACK_VALIDATION
454 bool "Compile-time stack metadata validation"
455 depends on HAVE_STACK_VALIDATION
456 default n
457 help
458 Add compile-time checks to validate stack metadata, including frame
459 pointers (if CONFIG_FRAME_POINTER is enabled). This helps ensure
460 that runtime stack traces are more reliable.
461
ee9f8fce 462 This is also a prerequisite for generation of ORC unwind data, which
11af8474 463 is needed for CONFIG_UNWINDER_ORC.
ee9f8fce 464
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465 For more information, see
466 tools/objtool/Documentation/stack-validation.txt.
467
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468config VMLINUX_VALIDATION
469 bool
470 depends on STACK_VALIDATION && DEBUG_ENTRY && !PARAVIRT
471 default y
472
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473config VMLINUX_MAP
474 bool "Generate vmlinux.map file when linking"
475 depends on EXPERT
476 help
477 Selecting this option will pass "-Map=vmlinux.map" to ld
478 when linking vmlinux. That file can be useful for verifying
479 and debugging magic section games, and for seeing which
480 pieces of code get eliminated with
481 CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.
482
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483config DEBUG_FORCE_WEAK_PER_CPU
484 bool "Force weak per-cpu definitions"
485 depends on DEBUG_KERNEL
8446f1d3 486 help
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487 s390 and alpha require percpu variables in modules to be
488 defined weak to work around addressing range issue which
489 puts the following two restrictions on percpu variable
490 definitions.
8446f1d3 491
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492 1. percpu symbols must be unique whether static or not
493 2. percpu variables can't be defined inside a function
8446f1d3 494
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495 To ensure that generic code follows the above rules, this
496 option forces all percpu variables to be defined as weak.
5f329089 497
6dfc0665 498endmenu # "Compiler options"
8446f1d3 499
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500menu "Generic Kernel Debugging Instruments"
501
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502config MAGIC_SYSRQ
503 bool "Magic SysRq key"
504 depends on !UML
505 help
506 If you say Y here, you will have some control over the system even
507 if the system crashes for example during kernel debugging (e.g., you
508 will be able to flush the buffer cache to disk, reboot the system
509 immediately or dump some status information). This is accomplished
510 by pressing various keys while holding SysRq (Alt+PrintScreen). It
511 also works on a serial console (on PC hardware at least), if you
512 send a BREAK and then within 5 seconds a command keypress. The
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513 keys are documented in <file:Documentation/admin-guide/sysrq.rst>.
514 Don't say Y unless you really know what this hack does.
8446f1d3 515
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516config MAGIC_SYSRQ_DEFAULT_ENABLE
517 hex "Enable magic SysRq key functions by default"
518 depends on MAGIC_SYSRQ
519 default 0x1
520 help
521 Specifies which SysRq key functions are enabled by default.
522 This may be set to 1 or 0 to enable or disable them all, or
f8998c22 523 to a bitmask as described in Documentation/admin-guide/sysrq.rst.
8eaede49 524
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525config MAGIC_SYSRQ_SERIAL
526 bool "Enable magic SysRq key over serial"
527 depends on MAGIC_SYSRQ
528 default y
529 help
530 Many embedded boards have a disconnected TTL level serial which can
531 generate some garbage that can lead to spurious false sysrq detects.
532 This option allows you to decide whether you want to enable the
533 magic SysRq key.
534
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535config MAGIC_SYSRQ_SERIAL_SEQUENCE
536 string "Char sequence that enables magic SysRq over serial"
537 depends on MAGIC_SYSRQ_SERIAL
538 default ""
539 help
540 Specifies a sequence of characters that can follow BREAK to enable
541 SysRq on a serial console.
542
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543 If unsure, leave an empty string and the option will not be enabled.
544
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545config DEBUG_FS
546 bool "Debug Filesystem"
547 help
548 debugfs is a virtual file system that kernel developers use to put
549 debugging files into. Enable this option to be able to read and
550 write to these files.
551
552 For detailed documentation on the debugfs API, see
553 Documentation/filesystems/.
554
555 If unsure, say N.
556
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557choice
558 prompt "Debugfs default access"
559 depends on DEBUG_FS
560 default DEBUG_FS_ALLOW_ALL
561 help
562 This selects the default access restrictions for debugfs.
563 It can be overridden with kernel command line option
564 debugfs=[on,no-mount,off]. The restrictions apply for API access
565 and filesystem registration.
566
567config DEBUG_FS_ALLOW_ALL
568 bool "Access normal"
569 help
570 No restrictions apply. Both API and filesystem registration
571 is on. This is the normal default operation.
572
573config DEBUG_FS_DISALLOW_MOUNT
574 bool "Do not register debugfs as filesystem"
575 help
576 The API is open but filesystem is not loaded. Clients can still do
577 their work and read with debug tools that do not need
578 debugfs filesystem.
579
580config DEBUG_FS_ALLOW_NONE
581 bool "No access"
582 help
583 Access is off. Clients get -PERM when trying to create nodes in
584 debugfs tree and debugfs is not registered as a filesystem.
585 Client can then back-off or continue without debugfs access.
586
587endchoice
588
6210b640 589source "lib/Kconfig.kgdb"
6210b640 590source "lib/Kconfig.ubsan"
2645d432 591source "lib/Kconfig.kcsan"
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592
593endmenu
594
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AB
595config DEBUG_KERNEL
596 bool "Kernel debugging"
fef2c9bc 597 help
f346f4b3
AB
598 Say Y here if you are developing drivers or trying to debug and
599 identify kernel problems.
fef2c9bc 600
c66d7a27
SK
601config DEBUG_MISC
602 bool "Miscellaneous debug code"
603 default DEBUG_KERNEL
604 depends on DEBUG_KERNEL
605 help
606 Say Y here if you need to enable miscellaneous debug code that should
607 be under a more specific debug option but isn't.
608
609
0610c8a8 610menu "Memory Debugging"
fef2c9bc 611
8636a1f9 612source "mm/Kconfig.debug"
fef2c9bc 613
0610c8a8
DH
614config DEBUG_OBJECTS
615 bool "Debug object operations"
616 depends on DEBUG_KERNEL
9c44bc03 617 help
0610c8a8
DH
618 If you say Y here, additional code will be inserted into the
619 kernel to track the life time of various objects and validate
620 the operations on those objects.
9c44bc03 621
0610c8a8
DH
622config DEBUG_OBJECTS_SELFTEST
623 bool "Debug objects selftest"
624 depends on DEBUG_OBJECTS
625 help
626 This enables the selftest of the object debug code.
9c44bc03 627
0610c8a8
DH
628config DEBUG_OBJECTS_FREE
629 bool "Debug objects in freed memory"
630 depends on DEBUG_OBJECTS
631 help
632 This enables checks whether a k/v free operation frees an area
633 which contains an object which has not been deactivated
634 properly. This can make kmalloc/kfree-intensive workloads
635 much slower.
3ac7fe5a 636
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TG
637config DEBUG_OBJECTS_TIMERS
638 bool "Debug timer objects"
639 depends on DEBUG_OBJECTS
640 help
641 If you say Y here, additional code will be inserted into the
642 timer routines to track the life time of timer objects and
643 validate the timer operations.
644
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TG
645config DEBUG_OBJECTS_WORK
646 bool "Debug work objects"
647 depends on DEBUG_OBJECTS
648 help
649 If you say Y here, additional code will be inserted into the
650 work queue routines to track the life time of work objects and
651 validate the work operations.
652
551d55a9
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653config DEBUG_OBJECTS_RCU_HEAD
654 bool "Debug RCU callbacks objects"
fc2ecf7e 655 depends on DEBUG_OBJECTS
551d55a9
MD
656 help
657 Enable this to turn on debugging of RCU list heads (call_rcu() usage).
658
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TH
659config DEBUG_OBJECTS_PERCPU_COUNTER
660 bool "Debug percpu counter objects"
661 depends on DEBUG_OBJECTS
662 help
663 If you say Y here, additional code will be inserted into the
664 percpu counter routines to track the life time of percpu counter
665 objects and validate the percpu counter operations.
666
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667config DEBUG_OBJECTS_ENABLE_DEFAULT
668 int "debug_objects bootup default value (0-1)"
68d4b3df
KK
669 range 0 1
670 default "1"
671 depends on DEBUG_OBJECTS
672 help
673 Debug objects boot parameter default value
3ae70205 674
1da177e4 675config DEBUG_SLAB
4a2f0acf 676 bool "Debug slab memory allocations"
4675ff05 677 depends on DEBUG_KERNEL && SLAB
1da177e4
LT
678 help
679 Say Y here to have the kernel do limited verification on memory
680 allocation as well as poisoning memory on free to catch use of freed
681 memory. This can make kmalloc/kfree-intensive workloads much slower.
682
f0630fff
CL
683config SLUB_DEBUG_ON
684 bool "SLUB debugging on by default"
4675ff05 685 depends on SLUB && SLUB_DEBUG
f0630fff
CL
686 default n
687 help
688 Boot with debugging on by default. SLUB boots by default with
689 the runtime debug capabilities switched off. Enabling this is
690 equivalent to specifying the "slub_debug" parameter on boot.
691 There is no support for more fine grained debug control like
692 possible with slub_debug=xxx. SLUB debugging may be switched
693 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
694 "slub_debug=-".
695
8ff12cfc
CL
696config SLUB_STATS
697 default n
698 bool "Enable SLUB performance statistics"
ab4d5ed5 699 depends on SLUB && SYSFS
8ff12cfc
CL
700 help
701 SLUB statistics are useful to debug SLUBs allocation behavior in
702 order find ways to optimize the allocator. This should never be
703 enabled for production use since keeping statistics slows down
704 the allocator by a few percentage points. The slabinfo command
705 supports the determination of the most active slabs to figure
706 out which slabs are relevant to a particular load.
707 Try running: slabinfo -DA
708
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709config HAVE_DEBUG_KMEMLEAK
710 bool
711
3bba00d7
CM
712config DEBUG_KMEMLEAK
713 bool "Kernel memory leak detector"
525c1f92 714 depends on DEBUG_KERNEL && HAVE_DEBUG_KMEMLEAK
79e0d9bd 715 select DEBUG_FS
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CM
716 select STACKTRACE if STACKTRACE_SUPPORT
717 select KALLSYMS
b60e26a2 718 select CRC32
3bba00d7
CM
719 help
720 Say Y here if you want to enable the memory leak
721 detector. The memory allocation/freeing is traced in a way
722 similar to the Boehm's conservative garbage collector, the
723 difference being that the orphan objects are not freed but
724 only shown in /sys/kernel/debug/kmemleak. Enabling this
725 feature will introduce an overhead to memory
700199b0 726 allocations. See Documentation/dev-tools/kmemleak.rst for more
3bba00d7
CM
727 details.
728
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DH
729 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
730 of finding leaks due to the slab objects poisoning.
731
732 In order to access the kmemleak file, debugfs needs to be
733 mounted (usually at /sys/kernel/debug).
734
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735config DEBUG_KMEMLEAK_MEM_POOL_SIZE
736 int "Kmemleak memory pool size"
0610c8a8 737 depends on DEBUG_KMEMLEAK
c59180ae 738 range 200 1000000
b751c52b 739 default 16000
0610c8a8
DH
740 help
741 Kmemleak must track all the memory allocations to avoid
742 reporting false positives. Since memory may be allocated or
c5665868
CM
743 freed before kmemleak is fully initialised, use a static pool
744 of metadata objects to track such callbacks. After kmemleak is
745 fully initialised, this memory pool acts as an emergency one
746 if slab allocations fail.
0610c8a8
DH
747
748config DEBUG_KMEMLEAK_TEST
749 tristate "Simple test for the kernel memory leak detector"
750 depends on DEBUG_KMEMLEAK && m
751 help
752 This option enables a module that explicitly leaks memory.
753
754 If unsure, say N.
755
756config DEBUG_KMEMLEAK_DEFAULT_OFF
757 bool "Default kmemleak to off"
758 depends on DEBUG_KMEMLEAK
759 help
760 Say Y here to disable kmemleak by default. It can then be enabled
761 on the command line via kmemleak=on.
762
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SK
763config DEBUG_KMEMLEAK_AUTO_SCAN
764 bool "Enable kmemleak auto scan thread on boot up"
765 default y
766 depends on DEBUG_KMEMLEAK
767 help
768 Depending on the cpu, kmemleak scan may be cpu intensive and can
769 stall user tasks at times. This option enables/disables automatic
770 kmemleak scan at boot up.
771
772 Say N here to disable kmemleak auto scan thread to stop automatic
773 scanning. Disabling this option disables automatic reporting of
774 memory leaks.
775
776 If unsure, say Y.
777
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778config DEBUG_STACK_USAGE
779 bool "Stack utilization instrumentation"
6c31da34 780 depends on DEBUG_KERNEL && !IA64
0610c8a8
DH
781 help
782 Enables the display of the minimum amount of free stack which each
783 task has ever had available in the sysrq-T and sysrq-P debug output.
784
785 This option will slow down process creation somewhat.
786
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787config SCHED_STACK_END_CHECK
788 bool "Detect stack corruption on calls to schedule()"
789 depends on DEBUG_KERNEL
790 default n
791 help
792 This option checks for a stack overrun on calls to schedule().
793 If the stack end location is found to be over written always panic as
794 the content of the corrupted region can no longer be trusted.
795 This is to ensure no erroneous behaviour occurs which could result in
796 data corruption or a sporadic crash at a later stage once the region
797 is examined. The runtime overhead introduced is minimal.
798
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799config ARCH_HAS_DEBUG_VM_PGTABLE
800 bool
801 help
802 An architecture should select this when it can successfully
803 build and run DEBUG_VM_PGTABLE.
804
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DH
805config DEBUG_VM
806 bool "Debug VM"
807 depends on DEBUG_KERNEL
808 help
809 Enable this to turn on extended checks in the virtual-memory system
68d4b3df 810 that may impact performance.
0610c8a8
DH
811
812 If unsure, say N.
813
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DB
814config DEBUG_VM_VMACACHE
815 bool "Debug VMA caching"
816 depends on DEBUG_VM
817 help
818 Enable this to turn on VMA caching debug information. Doing so
819 can cause significant overhead, so only enable it in non-production
820 environments.
821
822 If unsure, say N.
823
0610c8a8
DH
824config DEBUG_VM_RB
825 bool "Debug VM red-black trees"
826 depends on DEBUG_VM
827 help
a663dad6 828 Enable VM red-black tree debugging information and extra validations.
0610c8a8
DH
829
830 If unsure, say N.
831
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KS
832config DEBUG_VM_PGFLAGS
833 bool "Debug page-flags operations"
834 depends on DEBUG_VM
835 help
836 Enables extra validation on page flags operations.
837
838 If unsure, say N.
839
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840config DEBUG_VM_PGTABLE
841 bool "Debug arch page table for semantics compliance"
842 depends on MMU
843 depends on ARCH_HAS_DEBUG_VM_PGTABLE
844 default y if DEBUG_VM
845 help
846 This option provides a debug method which can be used to test
847 architecture page table helper functions on various platforms in
848 verifying if they comply with expected generic MM semantics. This
849 will help architecture code in making sure that any changes or
850 new additions of these helpers still conform to expected
851 semantics of the generic MM. Platforms will have to opt in for
852 this through ARCH_HAS_DEBUG_VM_PGTABLE.
853
854 If unsure, say N.
855
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LA
856config ARCH_HAS_DEBUG_VIRTUAL
857 bool
858
0610c8a8
DH
859config DEBUG_VIRTUAL
860 bool "Debug VM translations"
fa5b6ec9 861 depends on DEBUG_KERNEL && ARCH_HAS_DEBUG_VIRTUAL
0610c8a8
DH
862 help
863 Enable some costly sanity checks in virtual to page code. This can
864 catch mistakes with virt_to_page() and friends.
865
866 If unsure, say N.
867
868config DEBUG_NOMMU_REGIONS
869 bool "Debug the global anon/private NOMMU mapping region tree"
870 depends on DEBUG_KERNEL && !MMU
871 help
872 This option causes the global tree of anonymous and private mapping
873 regions to be regularly checked for invalid topology.
874
875config DEBUG_MEMORY_INIT
876 bool "Debug memory initialisation" if EXPERT
877 default !EXPERT
878 help
879 Enable this for additional checks during memory initialisation.
880 The sanity checks verify aspects of the VM such as the memory model
881 and other information provided by the architecture. Verbose
882 information will be printed at KERN_DEBUG loglevel depending
883 on the mminit_loglevel= command-line option.
884
885 If unsure, say Y
886
887config MEMORY_NOTIFIER_ERROR_INJECT
888 tristate "Memory hotplug notifier error injection module"
889 depends on MEMORY_HOTPLUG_SPARSE && NOTIFIER_ERROR_INJECTION
890 help
891 This option provides the ability to inject artificial errors to
892 memory hotplug notifier chain callbacks. It is controlled through
893 debugfs interface under /sys/kernel/debug/notifier-error-inject/memory
894
895 If the notifier call chain should be failed with some events
896 notified, write the error code to "actions/<notifier event>/error".
897
898 Example: Inject memory hotplug offline error (-12 == -ENOMEM)
899
900 # cd /sys/kernel/debug/notifier-error-inject/memory
901 # echo -12 > actions/MEM_GOING_OFFLINE/error
902 # echo offline > /sys/devices/system/memory/memoryXXX/state
903 bash: echo: write error: Cannot allocate memory
904
905 To compile this code as a module, choose M here: the module will
906 be called memory-notifier-error-inject.
907
908 If unsure, say N.
909
910config DEBUG_PER_CPU_MAPS
911 bool "Debug access to per_cpu maps"
912 depends on DEBUG_KERNEL
913 depends on SMP
914 help
915 Say Y to verify that the per_cpu map being accessed has
916 been set up. This adds a fair amount of code to kernel memory
917 and decreases performance.
918
919 Say N if unsure.
920
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TG
921config DEBUG_KMAP_LOCAL
922 bool "Debug kmap_local temporary mappings"
923 depends on DEBUG_KERNEL && KMAP_LOCAL
924 help
925 This option enables additional error checking for the kmap_local
926 infrastructure. Disable for production use.
927
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TG
928config ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
929 bool
930
931config DEBUG_KMAP_LOCAL_FORCE_MAP
932 bool "Enforce kmap_local temporary mappings"
933 depends on DEBUG_KERNEL && ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
934 select KMAP_LOCAL
935 select DEBUG_KMAP_LOCAL
936 help
937 This option enforces temporary mappings through the kmap_local
938 mechanism for non-highmem pages and on non-highmem systems.
939 Disable this for production systems!
940
0610c8a8
DH
941config DEBUG_HIGHMEM
942 bool "Highmem debugging"
943 depends on DEBUG_KERNEL && HIGHMEM
0e91a0c6 944 select DEBUG_KMAP_LOCAL_FORCE_MAP if ARCH_SUPPORTS_KMAP_LOCAL_FORCE_MAP
6e799cb6 945 select DEBUG_KMAP_LOCAL
0610c8a8 946 help
b1357c9f
GU
947 This option enables additional error checking for high memory
948 systems. Disable for production systems.
0610c8a8
DH
949
950config HAVE_DEBUG_STACKOVERFLOW
951 bool
952
953config DEBUG_STACKOVERFLOW
954 bool "Check for stack overflows"
955 depends on DEBUG_KERNEL && HAVE_DEBUG_STACKOVERFLOW
a7f7f624 956 help
0610c8a8 957 Say Y here if you want to check for overflows of kernel, IRQ
edb0ec07 958 and exception stacks (if your architecture uses them). This
0610c8a8
DH
959 option will show detailed messages if free stack space drops
960 below a certain limit.
961
962 These kinds of bugs usually occur when call-chains in the
963 kernel get too deep, especially when interrupts are
964 involved.
965
966 Use this in cases where you see apparently random memory
967 corruption, especially if it appears in 'struct thread_info'
968
969 If in doubt, say "N".
970
0b24becc 971source "lib/Kconfig.kasan"
0ce20dd8 972source "lib/Kconfig.kfence"
0b24becc 973
0610c8a8
DH
974endmenu # "Memory Debugging"
975
a304e1b8
DW
976config DEBUG_SHIRQ
977 bool "Debug shared IRQ handlers"
0244ad00 978 depends on DEBUG_KERNEL
a304e1b8 979 help
0a2fae2a
WS
980 Enable this to generate a spurious interrupt just before a shared
981 interrupt handler is deregistered (generating one when registering
982 is currently disabled). Drivers need to handle this correctly. Some
983 don't and need to be caught.
a304e1b8 984
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CD
985menu "Debug Oops, Lockups and Hangs"
986
987config PANIC_ON_OOPS
988 bool "Panic on Oops"
989 help
990 Say Y here to enable the kernel to panic when it oopses. This
991 has the same effect as setting oops=panic on the kernel command
992 line.
993
994 This feature is useful to ensure that the kernel does not do
995 anything erroneous after an oops which could result in data
996 corruption or other issues.
997
998 Say N if unsure.
999
1000config PANIC_ON_OOPS_VALUE
1001 int
1002 range 0 1
1003 default 0 if !PANIC_ON_OOPS
1004 default 1 if PANIC_ON_OOPS
1005
1006config PANIC_TIMEOUT
1007 int "panic timeout"
1008 default 0
1009 help
9d5b134f 1010 Set the timeout value (in seconds) until a reboot occurs when
f43a289d
CD
1011 the kernel panics. If n = 0, then we wait forever. A timeout
1012 value n > 0 will wait n seconds before rebooting, while a timeout
1013 value n < 0 will reboot immediately.
92aef8fb 1014
58687acb 1015config LOCKUP_DETECTOR
05a4a952
NP
1016 bool
1017
1018config SOFTLOCKUP_DETECTOR
1019 bool "Detect Soft Lockups"
dea20a3f 1020 depends on DEBUG_KERNEL && !S390
05a4a952 1021 select LOCKUP_DETECTOR
8446f1d3 1022 help
58687acb 1023 Say Y here to enable the kernel to act as a watchdog to detect
05a4a952 1024 soft lockups.
58687acb
DZ
1025
1026 Softlockups are bugs that cause the kernel to loop in kernel
5f329089 1027 mode for more than 20 seconds, without giving other tasks a
58687acb
DZ
1028 chance to run. The current stack trace is displayed upon
1029 detection and the system will stay locked up.
8446f1d3 1030
5f00ae0d
RD
1031config BOOTPARAM_SOFTLOCKUP_PANIC
1032 bool "Panic (Reboot) On Soft Lockups"
1033 depends on SOFTLOCKUP_DETECTOR
1034 help
1035 Say Y here to enable the kernel to panic on "soft lockups",
1036 which are bugs that cause the kernel to loop in kernel
1037 mode for more than 20 seconds (configurable using the watchdog_thresh
1038 sysctl), without giving other tasks a chance to run.
1039
1040 The panic can be used in combination with panic_timeout,
1041 to cause the system to reboot automatically after a
1042 lockup has been detected. This feature is useful for
1043 high-availability systems that have uptime guarantees and
1044 where a lockup must be resolved ASAP.
1045
1046 Say N if unsure.
1047
1048config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
1049 int
1050 depends on SOFTLOCKUP_DETECTOR
1051 range 0 1
1052 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
1053 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
1054
05a4a952
NP
1055config HARDLOCKUP_DETECTOR_PERF
1056 bool
1057 select SOFTLOCKUP_DETECTOR
1058
7edaeb68
TG
1059#
1060# Enables a timestamp based low pass filter to compensate for perf based
1061# hard lockup detection which runs too fast due to turbo modes.
1062#
1063config HARDLOCKUP_CHECK_TIMESTAMP
1064 bool
1065
05a4a952
NP
1066#
1067# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard
1068# lockup detector rather than the perf based detector.
1069#
1070config HARDLOCKUP_DETECTOR
1071 bool "Detect Hard Lockups"
1072 depends on DEBUG_KERNEL && !S390
1073 depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH
1074 select LOCKUP_DETECTOR
1075 select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF
05a4a952
NP
1076 help
1077 Say Y here to enable the kernel to act as a watchdog to detect
1078 hard lockups.
1079
58687acb 1080 Hardlockups are bugs that cause the CPU to loop in kernel mode
5f329089 1081 for more than 10 seconds, without letting other interrupts have a
58687acb
DZ
1082 chance to run. The current stack trace is displayed upon detection
1083 and the system will stay locked up.
8446f1d3 1084
fef2c9bc
DZ
1085config BOOTPARAM_HARDLOCKUP_PANIC
1086 bool "Panic (Reboot) On Hard Lockups"
8f1f66ed 1087 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1088 help
1089 Say Y here to enable the kernel to panic on "hard lockups",
1090 which are bugs that cause the kernel to loop in kernel
5f329089
FLVC
1091 mode with interrupts disabled for more than 10 seconds (configurable
1092 using the watchdog_thresh sysctl).
fef2c9bc
DZ
1093
1094 Say N if unsure.
1095
1096config BOOTPARAM_HARDLOCKUP_PANIC_VALUE
1097 int
8f1f66ed 1098 depends on HARDLOCKUP_DETECTOR
fef2c9bc
DZ
1099 range 0 1
1100 default 0 if !BOOTPARAM_HARDLOCKUP_PANIC
1101 default 1 if BOOTPARAM_HARDLOCKUP_PANIC
1102
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MSB
1103config DETECT_HUNG_TASK
1104 bool "Detect Hung Tasks"
1105 depends on DEBUG_KERNEL
05a4a952 1106 default SOFTLOCKUP_DETECTOR
e162b39a 1107 help
0610c8a8
DH
1108 Say Y here to enable the kernel to detect "hung tasks",
1109 which are bugs that cause the task to be stuck in
96b03ab8 1110 uninterruptible "D" state indefinitely.
1da177e4 1111
0610c8a8
DH
1112 When a hung task is detected, the kernel will print the
1113 current stack trace (which you should report), but the
1114 task will stay in uninterruptible state. If lockdep is
1115 enabled then all held locks will also be reported. This
1116 feature has negligible overhead.
871751e2 1117
0610c8a8
DH
1118config DEFAULT_HUNG_TASK_TIMEOUT
1119 int "Default timeout for hung task detection (in seconds)"
1120 depends on DETECT_HUNG_TASK
1121 default 120
f0630fff 1122 help
0610c8a8
DH
1123 This option controls the default timeout (in seconds) used
1124 to determine when a task has become non-responsive and should
1125 be considered hung.
f0630fff 1126
0610c8a8
DH
1127 It can be adjusted at runtime via the kernel.hung_task_timeout_secs
1128 sysctl or by writing a value to
1129 /proc/sys/kernel/hung_task_timeout_secs.
8ff12cfc 1130
0610c8a8
DH
1131 A timeout of 0 disables the check. The default is two minutes.
1132 Keeping the default should be fine in most cases.
b69ec42b 1133
0610c8a8
DH
1134config BOOTPARAM_HUNG_TASK_PANIC
1135 bool "Panic (Reboot) On Hung Tasks"
1136 depends on DETECT_HUNG_TASK
3bba00d7 1137 help
0610c8a8
DH
1138 Say Y here to enable the kernel to panic on "hung tasks",
1139 which are bugs that cause the kernel to leave a task stuck
1140 in uninterruptible "D" state.
3bba00d7 1141
0610c8a8
DH
1142 The panic can be used in combination with panic_timeout,
1143 to cause the system to reboot automatically after a
1144 hung task has been detected. This feature is useful for
1145 high-availability systems that have uptime guarantees and
1146 where a hung tasks must be resolved ASAP.
bf96d1e3 1147
0610c8a8 1148 Say N if unsure.
bf96d1e3 1149
0610c8a8
DH
1150config BOOTPARAM_HUNG_TASK_PANIC_VALUE
1151 int
1152 depends on DETECT_HUNG_TASK
1153 range 0 1
1154 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
1155 default 1 if BOOTPARAM_HUNG_TASK_PANIC
3bba00d7 1156
82607adc
TH
1157config WQ_WATCHDOG
1158 bool "Detect Workqueue Stalls"
1159 depends on DEBUG_KERNEL
1160 help
1161 Say Y here to enable stall detection on workqueues. If a
1162 worker pool doesn't make forward progress on a pending work
1163 item for over a given amount of time, 30s by default, a
1164 warning message is printed along with dump of workqueue
1165 state. This can be configured through kernel parameter
1166 "workqueue.watchdog_thresh" and its sysfs counterpart.
1167
30428ef5
KK
1168config TEST_LOCKUP
1169 tristate "Test module to generate lockups"
63646bc9 1170 depends on m
30428ef5
KK
1171 help
1172 This builds the "test_lockup" module that helps to make sure
1173 that watchdogs and lockup detectors are working properly.
1174
1175 Depending on module parameters it could emulate soft or hard
1176 lockup, "hung task", or locking arbitrary lock for a long time.
1177 Also it could generate series of lockups with cooling-down periods.
1178
1179 If unsure, say N.
1180
92aef8fb
DH
1181endmenu # "Debug lockups and hangs"
1182
ebebdd09 1183menu "Scheduler Debugging"
5800dc3c 1184
0610c8a8
DH
1185config SCHED_DEBUG
1186 bool "Collect scheduler debugging info"
1187 depends on DEBUG_KERNEL && PROC_FS
1188 default y
0822ee4a 1189 help
0610c8a8
DH
1190 If you say Y here, the /proc/sched_debug file will be provided
1191 that can help debug the scheduler. The runtime overhead of this
1192 option is minimal.
0822ee4a 1193
f6db8347
NR
1194config SCHED_INFO
1195 bool
1196 default n
1197
0610c8a8
DH
1198config SCHEDSTATS
1199 bool "Collect scheduler statistics"
1200 depends on DEBUG_KERNEL && PROC_FS
f6db8347 1201 select SCHED_INFO
0610c8a8
DH
1202 help
1203 If you say Y here, additional code will be inserted into the
1204 scheduler and related routines to collect statistics about
1205 scheduler behavior and provide them in /proc/schedstat. These
1206 stats may be useful for both tuning and debugging the scheduler
1207 If you aren't debugging the scheduler or trying to tune a specific
1208 application, you can say N to avoid the very slight overhead
1209 this adds.
0822ee4a 1210
ebebdd09 1211endmenu
0d9e2632 1212
3c17ad19
JS
1213config DEBUG_TIMEKEEPING
1214 bool "Enable extra timekeeping sanity checking"
1215 help
1216 This option will enable additional timekeeping sanity checks
1217 which may be helpful when diagnosing issues where timekeeping
1218 problems are suspected.
1219
1220 This may include checks in the timekeeping hotpaths, so this
1221 option may have a (very small) performance impact to some
1222 workloads.
1223
1224 If unsure, say N.
1225
1da177e4
LT
1226config DEBUG_PREEMPT
1227 bool "Debug preemptible kernel"
9f472869 1228 depends on DEBUG_KERNEL && PREEMPTION && TRACE_IRQFLAGS_SUPPORT
1da177e4
LT
1229 default y
1230 help
1231 If you say Y here then the kernel will use a debug variant of the
1232 commonly used smp_processor_id() function and will print warnings
1233 if kernel code uses it in a preemption-unsafe way. Also, the kernel
1234 will detect preemption count underflows.
1235
9eade16b
DH
1236menu "Lock Debugging (spinlocks, mutexes, etc...)"
1237
f07cbebb
WL
1238config LOCK_DEBUGGING_SUPPORT
1239 bool
1240 depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
1241 default y
1242
19193bca
WL
1243config PROVE_LOCKING
1244 bool "Lock debugging: prove locking correctness"
1245 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1246 select LOCKDEP
1247 select DEBUG_SPINLOCK
bb630f9f 1248 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca 1249 select DEBUG_RT_MUTEXES if RT_MUTEXES
c71fd893 1250 select DEBUG_RWSEMS
19193bca
WL
1251 select DEBUG_WW_MUTEX_SLOWPATH
1252 select DEBUG_LOCK_ALLOC
8fd8ad5c 1253 select PREEMPT_COUNT if !ARCH_NO_PREEMPT
19193bca
WL
1254 select TRACE_IRQFLAGS
1255 default n
1256 help
1257 This feature enables the kernel to prove that all locking
1258 that occurs in the kernel runtime is mathematically
1259 correct: that under no circumstance could an arbitrary (and
1260 not yet triggered) combination of observed locking
1261 sequences (on an arbitrary number of CPUs, running an
1262 arbitrary number of tasks and interrupt contexts) cause a
1263 deadlock.
1264
1265 In short, this feature enables the kernel to report locking
1266 related deadlocks before they actually occur.
1267
1268 The proof does not depend on how hard and complex a
1269 deadlock scenario would be to trigger: how many
1270 participant CPUs, tasks and irq-contexts would be needed
1271 for it to trigger. The proof also does not depend on
1272 timing: if a race and a resulting deadlock is possible
1273 theoretically (no matter how unlikely the race scenario
1274 is), it will be proven so and will immediately be
1275 reported by the kernel (once the event is observed that
1276 makes the deadlock theoretically possible).
1277
1278 If a deadlock is impossible (i.e. the locking rules, as
1279 observed by the kernel, are mathematically correct), the
1280 kernel reports nothing.
1281
1282 NOTE: this feature can also be enabled for rwlocks, mutexes
1283 and rwsems - in which case all dependencies between these
1284 different locking variants are observed and mapped too, and
1285 the proof of observed correctness is also maintained for an
1286 arbitrary combination of these separate locking variants.
1287
387b1468 1288 For more details, see Documentation/locking/lockdep-design.rst.
19193bca 1289
de8f5e4f
PZ
1290config PROVE_RAW_LOCK_NESTING
1291 bool "Enable raw_spinlock - spinlock nesting checks"
1292 depends on PROVE_LOCKING
1293 default n
1294 help
1295 Enable the raw_spinlock vs. spinlock nesting checks which ensure
1296 that the lock nesting rules for PREEMPT_RT enabled kernels are
1297 not violated.
1298
1299 NOTE: There are known nesting problems. So if you enable this
1300 option expect lockdep splats until these problems have been fully
1301 addressed which is work in progress. This config switch allows to
1302 identify and analyze these problems. It will be removed and the
9dbbc3b9 1303 check permanently enabled once the main issues have been fixed.
de8f5e4f
PZ
1304
1305 If unsure, select N.
1306
19193bca
WL
1307config LOCK_STAT
1308 bool "Lock usage statistics"
1309 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
1310 select LOCKDEP
1311 select DEBUG_SPINLOCK
bb630f9f 1312 select DEBUG_MUTEXES if !PREEMPT_RT
19193bca
WL
1313 select DEBUG_RT_MUTEXES if RT_MUTEXES
1314 select DEBUG_LOCK_ALLOC
1315 default n
1316 help
1317 This feature enables tracking lock contention points
1318
387b1468 1319 For more details, see Documentation/locking/lockstat.rst
19193bca
WL
1320
1321 This also enables lock events required by "perf lock",
1322 subcommand of perf.
1323 If you want to use "perf lock", you also need to turn on
1324 CONFIG_EVENT_TRACING.
1325
1326 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
1327 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
1328
e7eebaf6
IM
1329config DEBUG_RT_MUTEXES
1330 bool "RT Mutex debugging, deadlock detection"
e7eebaf6
IM
1331 depends on DEBUG_KERNEL && RT_MUTEXES
1332 help
1333 This allows rt mutex semantics violations and rt mutex related
1334 deadlocks (lockups) to be detected and reported automatically.
1335
1da177e4 1336config DEBUG_SPINLOCK
4d9f34ad 1337 bool "Spinlock and rw-lock debugging: basic checks"
1da177e4 1338 depends on DEBUG_KERNEL
e335e3eb 1339 select UNINLINE_SPIN_UNLOCK
1da177e4
LT
1340 help
1341 Say Y here and build SMP to catch missing spinlock initialization
1342 and certain other kinds of spinlock errors commonly made. This is
1343 best used in conjunction with the NMI watchdog so that spinlock
1344 deadlocks are also debuggable.
1345
4d9f34ad
IM
1346config DEBUG_MUTEXES
1347 bool "Mutex debugging: basic checks"
bb630f9f 1348 depends on DEBUG_KERNEL && !PREEMPT_RT
4d9f34ad
IM
1349 help
1350 This feature allows mutex semantics violations to be detected and
1351 reported.
1352
23010027
DV
1353config DEBUG_WW_MUTEX_SLOWPATH
1354 bool "Wait/wound mutex debugging: Slowpath testing"
f07cbebb 1355 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
23010027
DV
1356 select DEBUG_LOCK_ALLOC
1357 select DEBUG_SPINLOCK
bb630f9f
TG
1358 select DEBUG_MUTEXES if !PREEMPT_RT
1359 select DEBUG_RT_MUTEXES if PREEMPT_RT
23010027
DV
1360 help
1361 This feature enables slowpath testing for w/w mutex users by
1362 injecting additional -EDEADLK wound/backoff cases. Together with
1363 the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
1364 will test all possible w/w mutex interface abuse with the
1365 exception of simply not acquiring all the required locks.
4d692373
RC
1366 Note that this feature can introduce significant overhead, so
1367 it really should not be enabled in a production or distro kernel,
1368 even a debug kernel. If you are a driver writer, enable it. If
1369 you are a distro, do not.
23010027 1370
5149cbac
WL
1371config DEBUG_RWSEMS
1372 bool "RW Semaphore debugging: basic checks"
c71fd893 1373 depends on DEBUG_KERNEL
5149cbac 1374 help
c71fd893
WL
1375 This debugging feature allows mismatched rw semaphore locks
1376 and unlocks to be detected and reported.
5149cbac 1377
4d9f34ad
IM
1378config DEBUG_LOCK_ALLOC
1379 bool "Lock debugging: detect incorrect freeing of live locks"
f07cbebb 1380 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1381 select DEBUG_SPINLOCK
bb630f9f 1382 select DEBUG_MUTEXES if !PREEMPT_RT
f5694788 1383 select DEBUG_RT_MUTEXES if RT_MUTEXES
4d9f34ad
IM
1384 select LOCKDEP
1385 help
1386 This feature will check whether any held lock (spinlock, rwlock,
1387 mutex or rwsem) is incorrectly freed by the kernel, via any of the
1388 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
1389 vfree(), etc.), whether a live lock is incorrectly reinitialized via
1390 spin_lock_init()/mutex_init()/etc., or whether there is any lock
1391 held during task exit.
1392
4d9f34ad
IM
1393config LOCKDEP
1394 bool
f07cbebb 1395 depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
4d9f34ad 1396 select STACKTRACE
4d9f34ad
IM
1397 select KALLSYMS
1398 select KALLSYMS_ALL
1399
395102db
DJ
1400config LOCKDEP_SMALL
1401 bool
1402
5dc33592
TH
1403config LOCKDEP_BITS
1404 int "Bitsize for MAX_LOCKDEP_ENTRIES"
1405 depends on LOCKDEP && !LOCKDEP_SMALL
1406 range 10 30
1407 default 15
1408 help
1409 Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
1410
1411config LOCKDEP_CHAINS_BITS
1412 int "Bitsize for MAX_LOCKDEP_CHAINS"
1413 depends on LOCKDEP && !LOCKDEP_SMALL
1414 range 10 30
1415 default 16
1416 help
1417 Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
1418
1419config LOCKDEP_STACK_TRACE_BITS
1420 int "Bitsize for MAX_STACK_TRACE_ENTRIES"
1421 depends on LOCKDEP && !LOCKDEP_SMALL
1422 range 10 30
1423 default 19
1424 help
1425 Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
1426
1427config LOCKDEP_STACK_TRACE_HASH_BITS
1428 int "Bitsize for STACK_TRACE_HASH_SIZE"
1429 depends on LOCKDEP && !LOCKDEP_SMALL
1430 range 10 30
1431 default 14
1432 help
1433 Try increasing this value if you need large MAX_STACK_TRACE_ENTRIES.
1434
1435config LOCKDEP_CIRCULAR_QUEUE_BITS
1436 int "Bitsize for elements in circular_queue struct"
1437 depends on LOCKDEP
1438 range 10 30
1439 default 12
1440 help
1441 Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.
1442
4d9f34ad
IM
1443config DEBUG_LOCKDEP
1444 bool "Lock dependency engine debugging"
517e7aa5 1445 depends on DEBUG_KERNEL && LOCKDEP
997acaf6 1446 select DEBUG_IRQFLAGS
4d9f34ad
IM
1447 help
1448 If you say Y here, the lock dependency engine will do
1449 additional runtime checks to debug itself, at the price
1450 of more runtime overhead.
1451
d902db1e
FW
1452config DEBUG_ATOMIC_SLEEP
1453 bool "Sleep inside atomic section checking"
e8f7c70f 1454 select PREEMPT_COUNT
1da177e4 1455 depends on DEBUG_KERNEL
87a4c375 1456 depends on !ARCH_NO_PREEMPT
1da177e4
LT
1457 help
1458 If you say Y here, various routines which may sleep will become very
d902db1e
FW
1459 noisy if they are called inside atomic sections: when a spinlock is
1460 held, inside an rcu read side critical section, inside preempt disabled
1461 sections, inside an interrupt, etc...
1da177e4 1462
cae2ed9a
IM
1463config DEBUG_LOCKING_API_SELFTESTS
1464 bool "Locking API boot-time self-tests"
1465 depends on DEBUG_KERNEL
1466 help
1467 Say Y here if you want the kernel to run a short self-test during
1468 bootup. The self-test checks whether common types of locking bugs
1469 are detected by debugging mechanisms or not. (if you disable
9dbbc3b9 1470 lock debugging then those bugs won't be detected of course.)
cae2ed9a
IM
1471 The following locking APIs are covered: spinlocks, rwlocks,
1472 mutexes and rwsems.
1473
0af3fe1e
PM
1474config LOCK_TORTURE_TEST
1475 tristate "torture tests for locking"
1476 depends on DEBUG_KERNEL
1477 select TORTURE_TEST
0af3fe1e
PM
1478 help
1479 This option provides a kernel module that runs torture tests
1480 on kernel locking primitives. The kernel module may be built
1481 after the fact on the running kernel to be tested, if desired.
1482
1483 Say Y here if you want kernel locking-primitive torture tests
1484 to be built into the kernel.
1485 Say M if you want these torture tests to build as a module.
1486 Say N if you are unsure.
1487
f2a5fec1
CW
1488config WW_MUTEX_SELFTEST
1489 tristate "Wait/wound mutex selftests"
1490 help
1491 This option provides a kernel module that runs tests on the
1492 on the struct ww_mutex locking API.
1493
1494 It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
1495 with this test harness.
1496
1497 Say M if you want these self tests to build as a module.
1498 Say N if you are unsure.
1499
e9d338a0
PM
1500config SCF_TORTURE_TEST
1501 tristate "torture tests for smp_call_function*()"
1502 depends on DEBUG_KERNEL
1503 select TORTURE_TEST
1504 help
1505 This option provides a kernel module that runs torture tests
1506 on the smp_call_function() family of primitives. The kernel
1507 module may be built after the fact on the running kernel to
1508 be tested, if desired.
1509
35feb604
PM
1510config CSD_LOCK_WAIT_DEBUG
1511 bool "Debugging for csd_lock_wait(), called from smp_call_function*()"
1512 depends on DEBUG_KERNEL
1513 depends on 64BIT
1514 default n
1515 help
1516 This option enables debug prints when CPUs are slow to respond
1517 to the smp_call_function*() IPI wrappers. These debug prints
1518 include the IPI handler function currently executing (if any)
1519 and relevant stack traces.
1520
9eade16b 1521endmenu # lock debugging
8637c099 1522
9eade16b 1523config TRACE_IRQFLAGS
ed004953 1524 depends on TRACE_IRQFLAGS_SUPPORT
9eade16b 1525 bool
5ca43f6c 1526 help
9eade16b
DH
1527 Enables hooks to interrupt enabling and disabling for
1528 either tracing or lock debugging.
5ca43f6c 1529
ed004953 1530config TRACE_IRQFLAGS_NMI
1531 def_bool y
1532 depends on TRACE_IRQFLAGS
1533 depends on TRACE_IRQFLAGS_NMI_SUPPORT
1534
997acaf6
MR
1535config DEBUG_IRQFLAGS
1536 bool "Debug IRQ flag manipulation"
1537 help
1538 Enables checks for potentially unsafe enabling or disabling of
1539 interrupts, such as calling raw_local_irq_restore() when interrupts
1540 are enabled.
1541
8637c099 1542config STACKTRACE
0c38e1fe 1543 bool "Stack backtrace support"
8637c099 1544 depends on STACKTRACE_SUPPORT
0c38e1fe
DJ
1545 help
1546 This option causes the kernel to create a /proc/pid/stack for
1547 every process, showing its current stack trace.
1548 It is also used by various kernel debugging features that require
1549 stack trace generation.
5ca43f6c 1550
eecabf56
TT
1551config WARN_ALL_UNSEEDED_RANDOM
1552 bool "Warn for all uses of unseeded randomness"
1553 default n
d06bfd19
JD
1554 help
1555 Some parts of the kernel contain bugs relating to their use of
1556 cryptographically secure random numbers before it's actually possible
1557 to generate those numbers securely. This setting ensures that these
1558 flaws don't go unnoticed, by enabling a message, should this ever
1559 occur. This will allow people with obscure setups to know when things
1560 are going wrong, so that they might contact developers about fixing
1561 it.
1562
eecabf56
TT
1563 Unfortunately, on some models of some architectures getting
1564 a fully seeded CRNG is extremely difficult, and so this can
1565 result in dmesg getting spammed for a surprisingly long
1566 time. This is really bad from a security perspective, and
1567 so architecture maintainers really need to do what they can
1568 to get the CRNG seeded sooner after the system is booted.
4c5d114e 1569 However, since users cannot do anything actionable to
9713777e 1570 address this, by default this option is disabled.
eecabf56
TT
1571
1572 Say Y here if you want to receive warnings for all uses of
1573 unseeded randomness. This will be of use primarily for
4c5d114e 1574 those developers interested in improving the security of
eecabf56
TT
1575 Linux kernels running on their architecture (or
1576 subarchitecture).
d06bfd19 1577
1da177e4
LT
1578config DEBUG_KOBJECT
1579 bool "kobject debugging"
1580 depends on DEBUG_KERNEL
1581 help
1582 If you say Y here, some extra kobject debugging messages will be sent
aca52c39 1583 to the syslog.
1da177e4 1584
c817a67e
RK
1585config DEBUG_KOBJECT_RELEASE
1586 bool "kobject release debugging"
2a999aa0 1587 depends on DEBUG_OBJECTS_TIMERS
c817a67e
RK
1588 help
1589 kobjects are reference counted objects. This means that their
1590 last reference count put is not predictable, and the kobject can
1591 live on past the point at which a driver decides to drop it's
1592 initial reference to the kobject gained on allocation. An
1593 example of this would be a struct device which has just been
1594 unregistered.
1595
1596 However, some buggy drivers assume that after such an operation,
1597 the memory backing the kobject can be immediately freed. This
1598 goes completely against the principles of a refcounted object.
1599
1600 If you say Y here, the kernel will delay the release of kobjects
1601 on the last reference count to improve the visibility of this
1602 kind of kobject release bug.
1603
9b2a60c4
CM
1604config HAVE_DEBUG_BUGVERBOSE
1605 bool
1606
3be5cbcd 1607menu "Debug kernel data structures"
1da177e4 1608
199a9afc
DJ
1609config DEBUG_LIST
1610 bool "Debug linked list manipulation"
4520bcb2 1611 depends on DEBUG_KERNEL || BUG_ON_DATA_CORRUPTION
199a9afc
DJ
1612 help
1613 Enable this to turn on extended checks in the linked-list
1614 walking routines.
1615
1616 If unsure, say N.
1617
8e18faea 1618config DEBUG_PLIST
b8cfff68
DS
1619 bool "Debug priority linked list manipulation"
1620 depends on DEBUG_KERNEL
1621 help
1622 Enable this to turn on extended checks in the priority-ordered
1623 linked-list (plist) walking routines. This checks the entire
1624 list multiple times during each manipulation.
1625
1626 If unsure, say N.
1627
d6ec0842
JA
1628config DEBUG_SG
1629 bool "Debug SG table operations"
1630 depends on DEBUG_KERNEL
1631 help
1632 Enable this to turn on checks on scatter-gather tables. This can
1633 help find problems with drivers that do not properly initialize
1634 their sg tables.
1635
1636 If unsure, say N.
1637
1b2439db
AV
1638config DEBUG_NOTIFIERS
1639 bool "Debug notifier call chains"
1640 depends on DEBUG_KERNEL
1641 help
1642 Enable this to turn on sanity checking for notifier call chains.
1643 This is most useful for kernel developers to make sure that
1644 modules properly unregister themselves from notifier chains.
1645 This is a relatively cheap check but if you care about maximum
1646 performance, say N.
1647
3be5cbcd
CD
1648config BUG_ON_DATA_CORRUPTION
1649 bool "Trigger a BUG when data corruption is detected"
1650 select DEBUG_LIST
1651 help
1652 Select this option if the kernel should BUG when it encounters
1653 data corruption in kernel memory structures when they get checked
1654 for validity.
1655
1656 If unsure, say N.
1657
1658endmenu
1659
e0e81739
DH
1660config DEBUG_CREDENTIALS
1661 bool "Debug credential management"
1662 depends on DEBUG_KERNEL
1663 help
1664 Enable this to turn on some debug checking for credential
1665 management. The additional code keeps track of the number of
1666 pointers from task_structs to any given cred struct, and checks to
1667 see that this number never exceeds the usage count of the cred
1668 struct.
1669
1670 Furthermore, if SELinux is enabled, this also checks that the
1671 security pointer in the cred struct is never seen to be invalid.
1672
1673 If unsure, say N.
1674
43a0a2a7 1675source "kernel/rcu/Kconfig.debug"
2f03e3ca 1676
f303fccb
TH
1677config DEBUG_WQ_FORCE_RR_CPU
1678 bool "Force round-robin CPU selection for unbound work items"
1679 depends on DEBUG_KERNEL
1680 default n
1681 help
1682 Workqueue used to implicitly guarantee that work items queued
1683 without explicit CPU specified are put on the local CPU. This
1684 guarantee is no longer true and while local CPU is still
1685 preferred work items may be put on foreign CPUs. Kernel
1686 parameter "workqueue.debug_force_rr_cpu" is added to force
1687 round-robin CPU selection to flush out usages which depend on the
1688 now broken guarantee. This config option enables the debug
1689 feature by default. When enabled, memory and cache locality will
1690 be impacted.
1691
757c989b
TG
1692config CPU_HOTPLUG_STATE_CONTROL
1693 bool "Enable CPU hotplug state control"
1694 depends on DEBUG_KERNEL
1695 depends on HOTPLUG_CPU
1696 default n
1697 help
1698 Allows to write steps between "offline" and "online" to the CPUs
1699 sysfs target file so states can be stepped granular. This is a debug
1700 option for now as the hotplug machinery cannot be stopped and
1701 restarted at arbitrary points yet.
1702
1703 Say N if your are unsure.
1704
09a74952
CD
1705config LATENCYTOP
1706 bool "Latency measuring infrastructure"
1707 depends on DEBUG_KERNEL
1708 depends on STACKTRACE_SUPPORT
1709 depends on PROC_FS
7d37cb2c 1710 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
09a74952
CD
1711 select KALLSYMS
1712 select KALLSYMS_ALL
1713 select STACKTRACE
1714 select SCHEDSTATS
09a74952
CD
1715 help
1716 Enable this option if you want to use the LatencyTOP tool
1717 to find out which userspace is blocking on what kernel operations.
1718
1719source "kernel/trace/Kconfig"
1720
1721config PROVIDE_OHCI1394_DMA_INIT
1722 bool "Remote debugging over FireWire early on boot"
1723 depends on PCI && X86
1724 help
1725 If you want to debug problems which hang or crash the kernel early
1726 on boot and the crashing machine has a FireWire port, you can use
1727 this feature to remotely access the memory of the crashed machine
1728 over FireWire. This employs remote DMA as part of the OHCI1394
1729 specification which is now the standard for FireWire controllers.
1730
1731 With remote DMA, you can monitor the printk buffer remotely using
1732 firescope and access all memory below 4GB using fireproxy from gdb.
1733 Even controlling a kernel debugger is possible using remote DMA.
1734
1735 Usage:
1736
1737 If ohci1394_dma=early is used as boot parameter, it will initialize
1738 all OHCI1394 controllers which are found in the PCI config space.
1739
1740 As all changes to the FireWire bus such as enabling and disabling
1741 devices cause a bus reset and thereby disable remote DMA for all
1742 devices, be sure to have the cable plugged and FireWire enabled on
1743 the debugging host before booting the debug target for debugging.
1744
1745 This code (~1k) is freed after boot. By then, the firewire stack
1746 in charge of the OHCI-1394 controllers should be used instead.
1747
a74e2a22 1748 See Documentation/core-api/debugging-via-ohci1394.rst for more information.
09a74952 1749
045f6d79
CD
1750source "samples/Kconfig"
1751
1752config ARCH_HAS_DEVMEM_IS_ALLOWED
1753 bool
1754
1755config STRICT_DEVMEM
1756 bool "Filter access to /dev/mem"
1757 depends on MMU && DEVMEM
527701ed 1758 depends on ARCH_HAS_DEVMEM_IS_ALLOWED || GENERIC_LIB_DEVMEM_IS_ALLOWED
045f6d79
CD
1759 default y if PPC || X86 || ARM64
1760 help
1761 If this option is disabled, you allow userspace (root) access to all
1762 of memory, including kernel and userspace memory. Accidental
1763 access to this is obviously disastrous, but specific access can
1764 be used by people debugging the kernel. Note that with PAT support
1765 enabled, even in this case there are restrictions on /dev/mem
1766 use due to the cache aliasing requirements.
1767
1768 If this option is switched on, and IO_STRICT_DEVMEM=n, the /dev/mem
1769 file only allows userspace access to PCI space and the BIOS code and
1770 data regions. This is sufficient for dosemu and X and all common
1771 users of /dev/mem.
1772
1773 If in doubt, say Y.
1774
1775config IO_STRICT_DEVMEM
1776 bool "Filter I/O access to /dev/mem"
1777 depends on STRICT_DEVMEM
1778 help
1779 If this option is disabled, you allow userspace (root) access to all
1780 io-memory regardless of whether a driver is actively using that
1781 range. Accidental access to this is obviously disastrous, but
1782 specific access can be used by people debugging kernel drivers.
1783
1784 If this option is switched on, the /dev/mem file only allows
1785 userspace access to *idle* io-memory ranges (see /proc/iomem) This
1786 may break traditional users of /dev/mem (dosemu, legacy X, etc...)
1787 if the driver using a given range cannot be disabled.
1788
1789 If in doubt, say Y.
1790
1791menu "$(SRCARCH) Debugging"
1792
1793source "arch/$(SRCARCH)/Kconfig.debug"
1794
1795endmenu
1796
1797menu "Kernel Testing and Coverage"
1798
09a74952
CD
1799source "lib/kunit/Kconfig"
1800
8d438288
AM
1801config NOTIFIER_ERROR_INJECTION
1802 tristate "Notifier error injection"
1803 depends on DEBUG_KERNEL
1804 select DEBUG_FS
1805 help
e41e85cc 1806 This option provides the ability to inject artificial errors to
8d438288
AM
1807 specified notifier chain callbacks. It is useful to test the error
1808 handling of notifier call chain failures.
1809
1810 Say N if unsure.
1811
048b9c35
AM
1812config PM_NOTIFIER_ERROR_INJECT
1813 tristate "PM notifier error injection module"
1814 depends on PM && NOTIFIER_ERROR_INJECTION
1815 default m if PM_DEBUG
1816 help
e41e85cc 1817 This option provides the ability to inject artificial errors to
048b9c35
AM
1818 PM notifier chain callbacks. It is controlled through debugfs
1819 interface /sys/kernel/debug/notifier-error-inject/pm
1820
1821 If the notifier call chain should be failed with some events
1822 notified, write the error code to "actions/<notifier event>/error".
1823
1824 Example: Inject PM suspend error (-12 = -ENOMEM)
1825
1826 # cd /sys/kernel/debug/notifier-error-inject/pm/
1827 # echo -12 > actions/PM_SUSPEND_PREPARE/error
1828 # echo mem > /sys/power/state
1829 bash: echo: write error: Cannot allocate memory
1830
1831 To compile this code as a module, choose M here: the module will
1832 be called pm-notifier-error-inject.
1833
1834 If unsure, say N.
1835
d526e85f
BH
1836config OF_RECONFIG_NOTIFIER_ERROR_INJECT
1837 tristate "OF reconfig notifier error injection module"
1838 depends on OF_DYNAMIC && NOTIFIER_ERROR_INJECTION
08dfb4dd 1839 help
e41e85cc 1840 This option provides the ability to inject artificial errors to
d526e85f 1841 OF reconfig notifier chain callbacks. It is controlled
08dfb4dd 1842 through debugfs interface under
d526e85f 1843 /sys/kernel/debug/notifier-error-inject/OF-reconfig/
08dfb4dd
AM
1844
1845 If the notifier call chain should be failed with some events
1846 notified, write the error code to "actions/<notifier event>/error".
1847
1848 To compile this code as a module, choose M here: the module will
e12a95f4 1849 be called of-reconfig-notifier-error-inject.
08dfb4dd
AM
1850
1851 If unsure, say N.
1852
02fff96a
NA
1853config NETDEV_NOTIFIER_ERROR_INJECT
1854 tristate "Netdev notifier error injection module"
1855 depends on NET && NOTIFIER_ERROR_INJECTION
1856 help
1857 This option provides the ability to inject artificial errors to
1858 netdevice notifier chain callbacks. It is controlled through debugfs
1859 interface /sys/kernel/debug/notifier-error-inject/netdev
1860
1861 If the notifier call chain should be failed with some events
1862 notified, write the error code to "actions/<notifier event>/error".
1863
1864 Example: Inject netdevice mtu change error (-22 = -EINVAL)
1865
1866 # cd /sys/kernel/debug/notifier-error-inject/netdev
1867 # echo -22 > actions/NETDEV_CHANGEMTU/error
1868 # ip link set eth0 mtu 1024
1869 RTNETLINK answers: Invalid argument
1870
1871 To compile this code as a module, choose M here: the module will
1872 be called netdev-notifier-error-inject.
1873
1874 If unsure, say N.
1875
f1b4bd06 1876config FUNCTION_ERROR_INJECTION
2c96ef54 1877 bool "Fault-injections of functions"
f1b4bd06 1878 depends on HAVE_FUNCTION_ERROR_INJECTION && KPROBES
2c96ef54
SRG
1879 help
1880 Add fault injections into various functions that are annotated with
1881 ALLOW_ERROR_INJECTION() in the kernel. BPF may also modify the return
1882 value of theses functions. This is useful to test error paths of code.
1883
1884 If unsure, say N
f1b4bd06 1885
6ff1cb35 1886config FAULT_INJECTION
1ab8509a
AM
1887 bool "Fault-injection framework"
1888 depends on DEBUG_KERNEL
329409ae
AM
1889 help
1890 Provide fault-injection framework.
1891 For more details, see Documentation/fault-injection/.
6ff1cb35 1892
8a8b6502 1893config FAILSLAB
1ab8509a
AM
1894 bool "Fault-injection capability for kmalloc"
1895 depends on FAULT_INJECTION
773ff60e 1896 depends on SLAB || SLUB
8a8b6502 1897 help
1ab8509a 1898 Provide fault-injection capability for kmalloc.
8a8b6502 1899
933e312e 1900config FAIL_PAGE_ALLOC
29b46fa3 1901 bool "Fault-injection capability for alloc_pages()"
1ab8509a 1902 depends on FAULT_INJECTION
933e312e 1903 help
1ab8509a 1904 Provide fault-injection capability for alloc_pages().
933e312e 1905
2c739ced
AL
1906config FAULT_INJECTION_USERCOPY
1907 bool "Fault injection capability for usercopy functions"
1908 depends on FAULT_INJECTION
1909 help
1910 Provides fault-injection capability to inject failures
1911 in usercopy functions (copy_from_user(), get_user(), ...).
1912
c17bb495 1913config FAIL_MAKE_REQUEST
86327d19 1914 bool "Fault-injection capability for disk IO"
581d4e28 1915 depends on FAULT_INJECTION && BLOCK
c17bb495 1916 help
1ab8509a 1917 Provide fault-injection capability for disk IO.
c17bb495 1918
581d4e28 1919config FAIL_IO_TIMEOUT
f4d01439 1920 bool "Fault-injection capability for faking disk interrupts"
581d4e28
JA
1921 depends on FAULT_INJECTION && BLOCK
1922 help
1923 Provide fault-injection capability on end IO handling. This
1924 will make the block layer "forget" an interrupt as configured,
1925 thus exercising the error handling.
1926
1927 Only works with drivers that use the generic timeout handling,
9dbbc3b9 1928 for others it won't do anything.
581d4e28 1929
ab51fbab
DB
1930config FAIL_FUTEX
1931 bool "Fault-injection capability for futexes"
1932 select DEBUG_FS
1933 depends on FAULT_INJECTION && FUTEX
1934 help
1935 Provide fault-injection capability for futexes.
1936
f1b4bd06
MP
1937config FAULT_INJECTION_DEBUG_FS
1938 bool "Debugfs entries for fault-injection capabilities"
1939 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
1940 help
1941 Enable configuration of fault-injection capabilities via debugfs.
1942
4b1a29a7
MH
1943config FAIL_FUNCTION
1944 bool "Fault-injection capability for functions"
1945 depends on FAULT_INJECTION_DEBUG_FS && FUNCTION_ERROR_INJECTION
1946 help
1947 Provide function-based fault-injection capability.
1948 This will allow you to override a specific function with a return
1949 with given return value. As a result, function caller will see
1950 an error value and have to handle it. This is useful to test the
1951 error handling in various subsystems.
1952
f1b4bd06
MP
1953config FAIL_MMC_REQUEST
1954 bool "Fault-injection capability for MMC IO"
1955 depends on FAULT_INJECTION_DEBUG_FS && MMC
6ff1cb35 1956 help
f1b4bd06
MP
1957 Provide fault-injection capability for MMC IO.
1958 This will make the mmc core return data errors. This is
1959 useful to test the error handling in the mmc block device
1960 and to test how the mmc host driver handles retries from
1961 the block device.
1df49008 1962
c782af25
CL
1963config FAIL_SUNRPC
1964 bool "Fault-injection capability for SunRPC"
1965 depends on FAULT_INJECTION_DEBUG_FS && SUNRPC_DEBUG
1966 help
1967 Provide fault-injection capability for SunRPC and
1968 its consumers.
1969
1df49008
AM
1970config FAULT_INJECTION_STACKTRACE_FILTER
1971 bool "stacktrace filter for fault-injection capabilities"
1972 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
6d690dca 1973 depends on !X86_64
1df49008 1974 select STACKTRACE
7d37cb2c 1975 depends on FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86
1df49008
AM
1976 help
1977 Provide stacktrace filter for fault-injection capabilities
267c4025 1978
09a74952
CD
1979config ARCH_HAS_KCOV
1980 bool
cc3fa840 1981 help
09a74952
CD
1982 An architecture should select this when it can successfully
1983 build and run with CONFIG_KCOV. This typically requires
1984 disabling instrumentation for some early boot code.
cc3fa840 1985
09a74952
CD
1986config CC_HAS_SANCOV_TRACE_PC
1987 def_bool $(cc-option,-fsanitize-coverage=trace-pc)
cc3fa840 1988
cc3fa840 1989
09a74952
CD
1990config KCOV
1991 bool "Code coverage for fuzzing"
1992 depends on ARCH_HAS_KCOV
1993 depends on CC_HAS_SANCOV_TRACE_PC || GCC_PLUGINS
1994 select DEBUG_FS
1995 select GCC_PLUGIN_SANCOV if !CC_HAS_SANCOV_TRACE_PC
1996 help
1997 KCOV exposes kernel code coverage information in a form suitable
1998 for coverage-guided fuzzing (randomized testing).
cc3fa840 1999
09a74952
CD
2000 If RANDOMIZE_BASE is enabled, PC values will not be stable across
2001 different machines and across reboots. If you need stable PC values,
2002 disable RANDOMIZE_BASE.
cc3fa840 2003
09a74952 2004 For more details, see Documentation/dev-tools/kcov.rst.
cc3fa840 2005
09a74952
CD
2006config KCOV_ENABLE_COMPARISONS
2007 bool "Enable comparison operands collection by KCOV"
2008 depends on KCOV
2009 depends on $(cc-option,-fsanitize-coverage=trace-cmp)
2010 help
2011 KCOV also exposes operands of every comparison in the instrumented
2012 code along with operand sizes and PCs of the comparison instructions.
2013 These operands can be used by fuzzing engines to improve the quality
2014 of fuzzing coverage.
cc3fa840 2015
09a74952
CD
2016config KCOV_INSTRUMENT_ALL
2017 bool "Instrument all code by default"
2018 depends on KCOV
2019 default y
2020 help
2021 If you are doing generic system call fuzzing (like e.g. syzkaller),
2022 then you will want to instrument the whole kernel and you should
2023 say y here. If you are doing more targeted fuzzing (like e.g.
2024 filesystem fuzzing with AFL) then you will want to enable coverage
2025 for more specific subsets of files, and should say n here.
84bc809e 2026
5ff3b30a
AK
2027config KCOV_IRQ_AREA_SIZE
2028 hex "Size of interrupt coverage collection area in words"
2029 depends on KCOV
2030 default 0x40000
2031 help
2032 KCOV uses preallocated per-cpu areas to collect coverage from
2033 soft interrupts. This specifies the size of those areas in the
2034 number of unsigned long words.
2035
d3deafaa
VL
2036menuconfig RUNTIME_TESTING_MENU
2037 bool "Runtime Testing"
908009e8 2038 def_bool y
d3deafaa
VL
2039
2040if RUNTIME_TESTING_MENU
881c5149
DH
2041
2042config LKDTM
2043 tristate "Linux Kernel Dump Test Tool Module"
2044 depends on DEBUG_FS
881c5149
DH
2045 help
2046 This module enables testing of the different dumping mechanisms by
2047 inducing system failures at predefined crash points.
2048 If you don't need it: say N
2049 Choose M here to compile this code as a module. The module will be
2050 called lkdtm.
2051
2052 Documentation on how to use the module can be found in
10ffebbe 2053 Documentation/fault-injection/provoke-crashes.rst
881c5149
DH
2054
2055config TEST_LIST_SORT
ebd09577
DL
2056 tristate "Linked list sorting test" if !KUNIT_ALL_TESTS
2057 depends on KUNIT
2058 default KUNIT_ALL_TESTS
881c5149
DH
2059 help
2060 Enable this to turn on 'list_sort()' function test. This test is
e327fd7c
GU
2061 executed only once during system boot (so affects only boot time),
2062 or at module load time.
881c5149
DH
2063
2064 If unsure, say N.
2065
6e24628d
IR
2066config TEST_MIN_HEAP
2067 tristate "Min heap test"
2068 depends on DEBUG_KERNEL || m
2069 help
2070 Enable this to turn on min heap function tests. This test is
2071 executed only once during system boot (so affects only boot time),
2072 or at module load time.
2073
2074 If unsure, say N.
2075
c5adae95 2076config TEST_SORT
36f33b56
DL
2077 tristate "Array-based sort test" if !KUNIT_ALL_TESTS
2078 depends on KUNIT
2079 default KUNIT_ALL_TESTS
c5adae95 2080 help
5c4e6798
GU
2081 This option enables the self-test function of 'sort()' at boot,
2082 or at module load time.
c5adae95
KF
2083
2084 If unsure, say N.
2085
5086ea4b
MR
2086config TEST_DIV64
2087 tristate "64bit/32bit division and modulo test"
2088 depends on DEBUG_KERNEL || m
2089 help
2090 Enable this to turn on 'do_div()' function test. This test is
2091 executed only once during system boot (so affects only boot time),
2092 or at module load time.
2093
2094 If unsure, say N.
2095
881c5149
DH
2096config KPROBES_SANITY_TEST
2097 bool "Kprobes sanity tests"
2098 depends on DEBUG_KERNEL
2099 depends on KPROBES
881c5149
DH
2100 help
2101 This option provides for testing basic kprobes functionality on
5a6cf77f 2102 boot. Samples of kprobe and kretprobe are inserted and
881c5149
DH
2103 verified for functionality.
2104
2105 Say N if you are unsure.
2106
2107config BACKTRACE_SELF_TEST
2108 tristate "Self test for the backtrace code"
2109 depends on DEBUG_KERNEL
881c5149
DH
2110 help
2111 This option provides a kernel module that can be used to test
2112 the kernel stack backtrace code. This option is not useful
2113 for distributions or general kernels, but only for kernel
2114 developers working on architecture code.
2115
2116 Note that if you want to also test saved backtraces, you will
2117 have to enable STACKTRACE as well.
2118
2119 Say N if you are unsure.
2120
910a742d
ML
2121config RBTREE_TEST
2122 tristate "Red-Black tree test"
7c993e11 2123 depends on DEBUG_KERNEL
910a742d
ML
2124 help
2125 A benchmark measuring the performance of the rbtree library.
2126 Also includes rbtree invariant checks.
2127
4b4f3acc
FB
2128config REED_SOLOMON_TEST
2129 tristate "Reed-Solomon library test"
2130 depends on DEBUG_KERNEL || m
2131 select REED_SOLOMON
2132 select REED_SOLOMON_ENC16
2133 select REED_SOLOMON_DEC16
2134 help
2135 This option enables the self-test function of rslib at boot,
2136 or at module load time.
2137
2138 If unsure, say N.
2139
fff3fd8a
ML
2140config INTERVAL_TREE_TEST
2141 tristate "Interval tree test"
0f789b67 2142 depends on DEBUG_KERNEL
a88cc108 2143 select INTERVAL_TREE
fff3fd8a
ML
2144 help
2145 A benchmark measuring the performance of the interval tree library
2146
623fd807
GT
2147config PERCPU_TEST
2148 tristate "Per cpu operations test"
2149 depends on m && DEBUG_KERNEL
2150 help
2151 Enable this option to build test module which validates per-cpu
2152 operations.
2153
2154 If unsure, say N.
2155
881c5149 2156config ATOMIC64_SELFTEST
55ded955 2157 tristate "Perform an atomic64_t self-test"
881c5149 2158 help
55ded955
GU
2159 Enable this option to test the atomic64_t functions at boot or
2160 at module load time.
881c5149
DH
2161
2162 If unsure, say N.
2163
2164config ASYNC_RAID6_TEST
2165 tristate "Self test for hardware accelerated raid6 recovery"
2166 depends on ASYNC_RAID6_RECOV
2167 select ASYNC_MEMCPY
a7f7f624 2168 help
881c5149
DH
2169 This is a one-shot self test that permutes through the
2170 recovery of all the possible two disk failure scenarios for a
2171 N-disk array. Recovery is performed with the asynchronous
2172 raid6 recovery routines, and will optionally use an offload
2173 engine if one is available.
2174
2175 If unsure, say N.
2176
64d1d77a
AS
2177config TEST_HEXDUMP
2178 tristate "Test functions located in the hexdump module at runtime"
2179
b2ff70a0
MC
2180config STRING_SELFTEST
2181 tristate "Test string functions at runtime"
2182
881c5149
DH
2183config TEST_STRING_HELPERS
2184 tristate "Test functions located in the string_helpers module at runtime"
2185
0b0600c8
TH
2186config TEST_STRSCPY
2187 tristate "Test strscpy*() family of functions at runtime"
2188
881c5149
DH
2189config TEST_KSTRTOX
2190 tristate "Test kstrto*() family of functions at runtime"
2191
707cc728
RV
2192config TEST_PRINTF
2193 tristate "Test printf() family of functions at runtime"
2194
50f530e1
RF
2195config TEST_SCANF
2196 tristate "Test scanf() family of functions at runtime"
2197
5fd003f5
DD
2198config TEST_BITMAP
2199 tristate "Test bitmap_*() family of functions at runtime"
5fd003f5
DD
2200 help
2201 Enable this option to test the bitmap functions at boot.
2202
2203 If unsure, say N.
2204
cfaff0e5
AS
2205config TEST_UUID
2206 tristate "Test functions located in the uuid module at runtime"
2207
ad3d6c72
MW
2208config TEST_XARRAY
2209 tristate "Test the XArray code at runtime"
2210
455a35a6
RV
2211config TEST_OVERFLOW
2212 tristate "Test check_*_overflow() functions at runtime"
2213
7e1e7763 2214config TEST_RHASHTABLE
9d6dbe1b 2215 tristate "Perform selftest on resizable hash table"
7e1e7763
TG
2216 help
2217 Enable this option to test the rhashtable functions at boot.
2218
2219 If unsure, say N.
2220
468a9428
GS
2221config TEST_HASH
2222 tristate "Perform selftest on hash functions"
468a9428 2223 help
2c956a60
JD
2224 Enable this option to test the kernel's integer (<linux/hash.h>),
2225 string (<linux/stringhash.h>), and siphash (<linux/siphash.h>)
2226 hash functions on boot (or module load).
468a9428
GS
2227
2228 This is intended to help people writing architecture-specific
2229 optimized versions. If unsure, say N.
2230
8ab8ba38
MW
2231config TEST_IDA
2232 tristate "Perform selftest on IDA functions"
2233
44091d29
JP
2234config TEST_PARMAN
2235 tristate "Perform selftest on priority array manager"
44091d29
JP
2236 depends on PARMAN
2237 help
2238 Enable this option to test priority array manager on boot
2239 (or module load).
2240
2241 If unsure, say N.
2242
6aed82de
DL
2243config TEST_IRQ_TIMINGS
2244 bool "IRQ timings selftest"
2245 depends on IRQ_TIMINGS
2246 help
2247 Enable this option to test the irq timings code on boot.
2248
2249 If unsure, say N.
2250
8a6f0b47 2251config TEST_LKM
93e9ef83 2252 tristate "Test module loading with 'hello world' module"
93e9ef83
KC
2253 depends on m
2254 help
2255 This builds the "test_module" module that emits "Hello, world"
2256 on printk when loaded. It is designed to be used for basic
2257 evaluation of the module loading subsystem (for example when
2258 validating module verification). It lacks any extra dependencies,
2259 and will not normally be loaded by the system unless explicitly
2260 requested by name.
2261
2262 If unsure, say N.
2263
c348c163 2264config TEST_BITOPS
6af132f3 2265 tristate "Test module for compilation of bitops operations"
c348c163
JB
2266 depends on m
2267 help
2268 This builds the "test_bitops" module that is much like the
2269 TEST_LKM module except that it does a basic exercise of the
6af132f3
WY
2270 set/clear_bit macros and get_count_order/long to make sure there are
2271 no compiler warnings from C=1 sparse checker or -Wextra
2272 compilations. It has no dependencies and doesn't run or load unless
2273 explicitly requested by name. for example: modprobe test_bitops.
c348c163
JB
2274
2275 If unsure, say N.
2276
3f21a6b7
URS
2277config TEST_VMALLOC
2278 tristate "Test module for stress/performance analysis of vmalloc allocator"
2279 default n
2280 depends on MMU
2281 depends on m
2282 help
2283 This builds the "test_vmalloc" module that should be used for
2284 stress and performance analysis. So, any new change for vmalloc
2285 subsystem can be evaluated from performance and stability point
2286 of view.
2287
2288 If unsure, say N.
2289
3e2a4c18
KC
2290config TEST_USER_COPY
2291 tristate "Test user/kernel boundary protections"
3e2a4c18
KC
2292 depends on m
2293 help
2294 This builds the "test_user_copy" module that runs sanity checks
2295 on the copy_to/from_user infrastructure, making sure basic
2296 user/kernel boundary testing is working. If it fails to load,
2297 a regression has been detected in the user/kernel memory boundary
2298 protections.
2299
2300 If unsure, say N.
2301
64a8946b
AS
2302config TEST_BPF
2303 tristate "Test BPF filter functionality"
98920ba6 2304 depends on m && NET
64a8946b
AS
2305 help
2306 This builds the "test_bpf" module that runs various test vectors
2307 against the BPF interpreter or BPF JIT compiler depending on the
2308 current setting. This is in particular useful for BPF JIT compiler
2309 development, but also to run regression tests against changes in
3c731eba
AS
2310 the interpreter code. It also enables test stubs for eBPF maps and
2311 verifier used by user space verifier testsuite.
64a8946b
AS
2312
2313 If unsure, say N.
2314
509e56b3
MB
2315config TEST_BLACKHOLE_DEV
2316 tristate "Test blackhole netdev functionality"
2317 depends on m && NET
2318 help
2319 This builds the "test_blackhole_dev" module that validates the
2320 data path through this blackhole netdev.
2321
2322 If unsure, say N.
2323
dceeb3e7 2324config FIND_BIT_BENCHMARK
4441fca0 2325 tristate "Test find_bit functions"
4441fca0
YN
2326 help
2327 This builds the "test_find_bit" module that measure find_*_bit()
2328 functions performance.
2329
2330 If unsure, say N.
2331
0a8adf58
KC
2332config TEST_FIRMWARE
2333 tristate "Test firmware loading via userspace interface"
0a8adf58
KC
2334 depends on FW_LOADER
2335 help
2336 This builds the "test_firmware" module that creates a userspace
2337 interface for testing firmware loading. This can be used to
2338 control the triggering of firmware loading without needing an
2339 actual firmware-using device. The contents can be rechecked by
2340 userspace.
2341
2342 If unsure, say N.
2343
9308f2f9
LR
2344config TEST_SYSCTL
2345 tristate "sysctl test driver"
9308f2f9
LR
2346 depends on PROC_SYSCTL
2347 help
2348 This builds the "test_sysctl" module. This driver enables to test the
2349 proc sysctl interfaces available to drivers safely without affecting
2350 production knobs which might alter system functionality.
2351
2352 If unsure, say N.
2353
d2585f51
VMI
2354config BITFIELD_KUNIT
2355 tristate "KUnit test bitfield functions at runtime"
2356 depends on KUNIT
2357 help
2358 Enable this option to test the bitfield functions at boot.
2359
2360 KUnit tests run during boot and output the results to the debug log
2361 in TAP format (http://testanything.org/). Only useful for kernel devs
2362 running the KUnit test harness, and not intended for inclusion into a
2363 production build.
2364
2365 For more information on KUnit and unit tests in general please refer
2366 to the KUnit documentation in Documentation/dev-tools/kunit/.
2367
2368 If unsure, say N.
2369
5df38ca6
AS
2370config RESOURCE_KUNIT_TEST
2371 tristate "KUnit test for resource API"
2372 depends on KUNIT
2373 help
2374 This builds the resource API unit test.
2375 Tests the logic of API provided by resource.c and ioport.h.
2376 For more information on KUnit and unit tests in general please refer
2377 to the KUnit documentation in Documentation/dev-tools/kunit/.
2378
2379 If unsure, say N.
2380
2cb80dbb 2381config SYSCTL_KUNIT_TEST
5f215aab 2382 tristate "KUnit test for sysctl" if !KUNIT_ALL_TESTS
2cb80dbb 2383 depends on KUNIT
5f215aab 2384 default KUNIT_ALL_TESTS
2cb80dbb
IZ
2385 help
2386 This builds the proc sysctl unit test, which runs on boot.
2387 Tests the API contract and implementation correctness of sysctl.
2388 For more information on KUnit and unit tests in general please refer
2389 to the KUnit documentation in Documentation/dev-tools/kunit/.
2390
2391 If unsure, say N.
2392
ea2dd7c0 2393config LIST_KUNIT_TEST
5f215aab 2394 tristate "KUnit Test for Kernel Linked-list structures" if !KUNIT_ALL_TESTS
ea2dd7c0 2395 depends on KUNIT
5f215aab 2396 default KUNIT_ALL_TESTS
ea2dd7c0
DG
2397 help
2398 This builds the linked list KUnit test suite.
2399 It tests that the API and basic functionality of the list_head type
2400 and associated macros.
2401
2402 KUnit tests run during boot and output the results to the debug log
d89775fc 2403 in TAP format (https://testanything.org/). Only useful for kernel devs
ea2dd7c0
DG
2404 running the KUnit test harness, and not intended for inclusion into a
2405 production build.
2406
2407 For more information on KUnit and unit tests in general please refer
2408 to the KUnit documentation in Documentation/dev-tools/kunit/.
2409
2410 If unsure, say N.
2411
33d599f0
MV
2412config LINEAR_RANGES_TEST
2413 tristate "KUnit test for linear_ranges"
2414 depends on KUNIT
2415 select LINEAR_RANGES
2416 help
2417 This builds the linear_ranges unit test, which runs on boot.
2418 Tests the linear_ranges logic correctness.
2419 For more information on KUnit and unit tests in general please refer
7546861a
AS
2420 to the KUnit documentation in Documentation/dev-tools/kunit/.
2421
2422 If unsure, say N.
2423
2424config CMDLINE_KUNIT_TEST
2425 tristate "KUnit test for cmdline API"
2426 depends on KUNIT
2427 help
2428 This builds the cmdline API unit test.
2429 Tests the logic of API provided by cmdline.c.
2430 For more information on KUnit and unit tests in general please refer
33d599f0
MV
2431 to the KUnit documentation in Documentation/dev-tools/kunit/.
2432
2433 If unsure, say N.
2434
6d511020
RF
2435config BITS_TEST
2436 tristate "KUnit test for bits.h"
2437 depends on KUNIT
2438 help
2439 This builds the bits unit test.
2440 Tests the logic of macros defined in bits.h.
2441 For more information on KUnit and unit tests in general please refer
2442 to the KUnit documentation in Documentation/dev-tools/kunit/.
2443
2444 If unsure, say N.
2445
1f9f78b1
OG
2446config SLUB_KUNIT_TEST
2447 tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
2448 depends on SLUB_DEBUG && KUNIT
2449 default KUNIT_ALL_TESTS
2450 help
2451 This builds SLUB allocator unit test.
2452 Tests SLUB cache debugging functionality.
2453 For more information on KUnit and unit tests in general please refer
2454 to the KUnit documentation in Documentation/dev-tools/kunit/.
2455
2456 If unsure, say N.
2457
b6c75c4a
TP
2458config RATIONAL_KUNIT_TEST
2459 tristate "KUnit test for rational.c" if !KUNIT_ALL_TESTS
8ba739ed 2460 depends on KUNIT && RATIONAL
b6c75c4a
TP
2461 default KUNIT_ALL_TESTS
2462 help
2463 This builds the rational math unit test.
2464 For more information on KUnit and unit tests in general please refer
2465 to the KUnit documentation in Documentation/dev-tools/kunit/.
2466
2467 If unsure, say N.
2468
e704f93a
DR
2469config TEST_UDELAY
2470 tristate "udelay test driver"
e704f93a
DR
2471 help
2472 This builds the "udelay_test" module that helps to make sure
2473 that udelay() is working properly.
2474
2475 If unsure, say N.
2476
2bf9e0ab
IM
2477config TEST_STATIC_KEYS
2478 tristate "Test static keys"
579e1acb
JB
2479 depends on m
2480 help
2bf9e0ab 2481 Test the static key interfaces.
579e1acb
JB
2482
2483 If unsure, say N.
2484
d9c6a72d
LR
2485config TEST_KMOD
2486 tristate "kmod stress tester"
d9c6a72d 2487 depends on m
d9c6a72d 2488 depends on NETDEVICES && NET_CORE && INET # for TUN
ae3d6a32 2489 depends on BLOCK
d9c6a72d
LR
2490 select TEST_LKM
2491 select XFS_FS
2492 select TUN
2493 select BTRFS_FS
2494 help
2495 Test the kernel's module loading mechanism: kmod. kmod implements
2496 support to load modules using the Linux kernel's usermode helper.
2497 This test provides a series of tests against kmod.
2498
2499 Although technically you can either build test_kmod as a module or
2500 into the kernel we disallow building it into the kernel since
2501 it stress tests request_module() and this will very likely cause
2502 some issues by taking over precious threads available from other
2503 module load requests, ultimately this could be fatal.
2504
2505 To run tests run:
2506
2507 tools/testing/selftests/kmod/kmod.sh --help
2508
2509 If unsure, say N.
2510
e4dace36
FF
2511config TEST_DEBUG_VIRTUAL
2512 tristate "Test CONFIG_DEBUG_VIRTUAL feature"
2513 depends on DEBUG_VIRTUAL
2514 help
2515 Test the kernel's ability to detect incorrect calls to
2516 virt_to_phys() done against the non-linear part of the
2517 kernel's virtual address map.
2518
2519 If unsure, say N.
2520
ce76d938
AS
2521config TEST_MEMCAT_P
2522 tristate "Test memcat_p() helper function"
2523 help
2524 Test the memcat_p() helper for correctly merging two
2525 pointer arrays together.
2526
2527 If unsure, say N.
2528
a2818ee4
JL
2529config TEST_LIVEPATCH
2530 tristate "Test livepatching"
2531 default n
bae05437 2532 depends on DYNAMIC_DEBUG
a2818ee4
JL
2533 depends on LIVEPATCH
2534 depends on m
2535 help
2536 Test kernel livepatching features for correctness. The tests will
2537 load test modules that will be livepatched in various scenarios.
2538
2539 To run all the livepatching tests:
2540
2541 make -C tools/testing/selftests TARGETS=livepatch run_tests
2542
2543 Alternatively, individual tests may be invoked:
2544
2545 tools/testing/selftests/livepatch/test-callbacks.sh
2546 tools/testing/selftests/livepatch/test-livepatch.sh
2547 tools/testing/selftests/livepatch/test-shadow-vars.sh
2548
2549 If unsure, say N.
2550
0a020d41
JP
2551config TEST_OBJAGG
2552 tristate "Perform selftest on object aggreration manager"
2553 default n
2554 depends on OBJAGG
2555 help
2556 Enable this option to test object aggregation manager on boot
2557 (or module load).
2558
0a020d41 2559
50ceaa95
KC
2560config TEST_STACKINIT
2561 tristate "Test level of stack variable initialization"
2562 help
2563 Test if the kernel is zero-initializing stack variables and
2564 padding. Coverage is controlled by compiler flags,
2565 CONFIG_GCC_PLUGIN_STRUCTLEAK, CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF,
2566 or CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL.
2567
2568 If unsure, say N.
2569
5015a300
AP
2570config TEST_MEMINIT
2571 tristate "Test heap/page initialization"
2572 help
2573 Test if the kernel is zero-initializing heap and page allocations.
2574 This can be useful to test init_on_alloc and init_on_free features.
2575
2576 If unsure, say N.
2577
b2ef9f5a
RC
2578config TEST_HMM
2579 tristate "Test HMM (Heterogeneous Memory Management)"
2580 depends on TRANSPARENT_HUGEPAGE
2581 depends on DEVICE_PRIVATE
2582 select HMM_MIRROR
2583 select MMU_NOTIFIER
2584 help
2585 This is a pseudo device driver solely for testing HMM.
2586 Say M here if you want to build the HMM test module.
2587 Doing so will allow you to run tools/testing/selftest/vm/hmm-tests.
2588
2589 If unsure, say N.
2590
e320d301
MWO
2591config TEST_FREE_PAGES
2592 tristate "Test freeing pages"
2593 help
2594 Test that a memory leak does not occur due to a race between
2595 freeing a block of pages and a speculative page reference.
2596 Loading this module is safe if your kernel has the bug fixed.
2597 If the bug is not fixed, it will leak gigabytes of memory and
2598 probably OOM your system.
2599
4185b3b9
PA
2600config TEST_FPU
2601 tristate "Test floating point operations in kernel space"
2602 depends on X86 && !KCOV_INSTRUMENT_ALL
2603 help
2604 Enable this option to add /sys/kernel/debug/selftest_helpers/test_fpu
2605 which will trigger a sequence of floating point operations. This is used
2606 for self-testing floating point control register setting in
2607 kernel_fpu_begin().
2608
2609 If unsure, say N.
2610
1253b9b8
PM
2611config TEST_CLOCKSOURCE_WATCHDOG
2612 tristate "Test clocksource watchdog in kernel space"
2613 depends on CLOCKSOURCE_WATCHDOG
2614 help
2615 Enable this option to create a kernel module that will trigger
2616 a test of the clocksource watchdog. This module may be loaded
2617 via modprobe or insmod in which case it will run upon being
2618 loaded, or it may be built in, in which case it will run
2619 shortly after boot.
2620
2621 If unsure, say N.
2622
d3deafaa 2623endif # RUNTIME_TESTING_MENU
cc3fa840 2624
dce44566
AK
2625config ARCH_USE_MEMTEST
2626 bool
2627 help
2628 An architecture should select this when it uses early_memtest()
2629 during boot process.
2630
cc3fa840
RD
2631config MEMTEST
2632 bool "Memtest"
dce44566 2633 depends on ARCH_USE_MEMTEST
a7f7f624 2634 help
cc3fa840 2635 This option adds a kernel parameter 'memtest', which allows memtest
dce44566 2636 to be set and executed.
cc3fa840
RD
2637 memtest=0, mean disabled; -- default
2638 memtest=1, mean do 1 test pattern;
2639 ...
2640 memtest=17, mean do 17 test patterns.
2641 If you are unsure how to answer this question, answer N.
2642
21266be9 2643
06ec64b8 2644
af9ca6f9
BB
2645config HYPERV_TESTING
2646 bool "Microsoft Hyper-V driver testing"
2647 default n
2648 depends on HYPERV && DEBUG_FS
2649 help
2650 Select this option to enable Hyper-V vmbus testing.
2651
045f6d79
CD
2652endmenu # "Kernel Testing and Coverage"
2653
75442fb0
MCC
2654source "Documentation/Kconfig"
2655
06ec64b8 2656endmenu # Kernel hacking