Commit | Line | Data |
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1da177e4 LT |
1 | |
2 | config PRINTK_TIME | |
3 | bool "Show timing information on printks" | |
d3b8b6e5 | 4 | depends on PRINTK |
1da177e4 LT |
5 | help |
6 | Selecting this option causes timing information to be | |
7 | included in printk output. This allows you to measure | |
8 | the interval between kernel operations, including bootup | |
9 | operations. This is useful for identifying long delays | |
10 | in kernel startup. | |
11 | ||
cebc04ba AM |
12 | config ENABLE_MUST_CHECK |
13 | bool "Enable __must_check logic" | |
14 | default y | |
15 | help | |
16 | Enable the __must_check logic in the kernel build. Disable this to | |
17 | suppress the "warning: ignoring return value of 'foo', declared with | |
18 | attribute warn_unused_result" messages. | |
1da177e4 | 19 | |
1da177e4 LT |
20 | config MAGIC_SYSRQ |
21 | bool "Magic SysRq key" | |
f346f4b3 | 22 | depends on !UML |
1da177e4 LT |
23 | help |
24 | If you say Y here, you will have some control over the system even | |
25 | if the system crashes for example during kernel debugging (e.g., you | |
26 | will be able to flush the buffer cache to disk, reboot the system | |
27 | immediately or dump some status information). This is accomplished | |
28 | by pressing various keys while holding SysRq (Alt+PrintScreen). It | |
29 | also works on a serial console (on PC hardware at least), if you | |
30 | send a BREAK and then within 5 seconds a command keypress. The | |
31 | keys are documented in <file:Documentation/sysrq.txt>. Don't say Y | |
32 | unless you really know what this hack does. | |
33 | ||
f71d20e9 AV |
34 | config UNUSED_SYMBOLS |
35 | bool "Enable unused/obsolete exported symbols" | |
36 | default y if X86 | |
37 | help | |
38 | Unused but exported symbols make the kernel needlessly bigger. For | |
39 | that reason most of these unused exports will soon be removed. This | |
40 | option is provided temporarily to provide a transition period in case | |
41 | some external kernel module needs one of these symbols anyway. If you | |
42 | encounter such a case in your module, consider if you are actually | |
43 | using the right API. (rationale: since nobody in the kernel is using | |
44 | this in a module, there is a pretty good chance it's actually the | |
45 | wrong interface to use). If you really need the symbol, please send a | |
46 | mail to the linux kernel mailing list mentioning the symbol and why | |
47 | you really need it, and what the merge plan to the mainline kernel for | |
48 | your module is. | |
49 | ||
bf4735a4 DM |
50 | config DEBUG_FS |
51 | bool "Debug Filesystem" | |
52 | depends on SYSFS | |
53 | help | |
54 | debugfs is a virtual file system that kernel developers use to put | |
55 | debugging files into. Enable this option to be able to read and | |
56 | write to these files. | |
57 | ||
58 | If unsure, say N. | |
59 | ||
60 | config HEADERS_CHECK | |
61 | bool "Run 'make headers_check' when building vmlinux" | |
62 | depends on !UML | |
63 | help | |
64 | This option will extract the user-visible kernel headers whenever | |
65 | building the kernel, and will run basic sanity checks on them to | |
66 | ensure that exported files do not attempt to include files which | |
67 | were not exported, etc. | |
68 | ||
69 | If you're making modifications to header files which are | |
70 | relevant for userspace, say 'Y', and check the headers | |
71 | exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in | |
72 | your build tree), to make sure they're suitable. | |
73 | ||
f346f4b3 AB |
74 | config DEBUG_KERNEL |
75 | bool "Kernel debugging" | |
76 | help | |
77 | Say Y here if you are developing drivers or trying to debug and | |
78 | identify kernel problems. | |
79 | ||
a304e1b8 DW |
80 | config DEBUG_SHIRQ |
81 | bool "Debug shared IRQ handlers" | |
82 | depends on DEBUG_KERNEL && GENERIC_HARDIRQS | |
83 | help | |
84 | Enable this to generate a spurious interrupt as soon as a shared | |
85 | interrupt handler is registered, and just before one is deregistered. | |
86 | Drivers ought to be able to handle interrupts coming in at those | |
87 | points; some don't and need to be caught. | |
88 | ||
1da177e4 LT |
89 | config LOG_BUF_SHIFT |
90 | int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL | |
91 | range 12 21 | |
fbb9ce95 | 92 | default 17 if S390 || LOCKDEP |
1da177e4 LT |
93 | default 16 if X86_NUMAQ || IA64 |
94 | default 15 if SMP | |
95 | default 14 | |
96 | help | |
97 | Select kernel log buffer size as a power of 2. | |
98 | Defaults and Examples: | |
99 | 17 => 128 KB for S/390 | |
100 | 16 => 64 KB for x86 NUMAQ or IA-64 | |
101 | 15 => 32 KB for SMP | |
102 | 14 => 16 KB for uniprocessor | |
103 | 13 => 8 KB | |
104 | 12 => 4 KB | |
105 | ||
8446f1d3 IM |
106 | config DETECT_SOFTLOCKUP |
107 | bool "Detect Soft Lockups" | |
dea20a3f | 108 | depends on DEBUG_KERNEL && !S390 |
8446f1d3 IM |
109 | default y |
110 | help | |
111 | Say Y here to enable the kernel to detect "soft lockups", | |
112 | which are bugs that cause the kernel to loop in kernel | |
113 | mode for more than 10 seconds, without giving other tasks a | |
114 | chance to run. | |
115 | ||
116 | When a soft-lockup is detected, the kernel will print the | |
117 | current stack trace (which you should report), but the | |
118 | system will stay locked up. This feature has negligible | |
119 | overhead. | |
120 | ||
121 | (Note that "hard lockups" are separate type of bugs that | |
122 | can be detected via the NMI-watchdog, on platforms that | |
123 | support it.) | |
124 | ||
1da177e4 LT |
125 | config SCHEDSTATS |
126 | bool "Collect scheduler statistics" | |
127 | depends on DEBUG_KERNEL && PROC_FS | |
128 | help | |
129 | If you say Y here, additional code will be inserted into the | |
130 | scheduler and related routines to collect statistics about | |
131 | scheduler behavior and provide them in /proc/schedstat. These | |
132 | stats may be useful for both tuning and debugging the scheduler | |
133 | If you aren't debugging the scheduler or trying to tune a specific | |
134 | application, you can say N to avoid the very slight overhead | |
135 | this adds. | |
136 | ||
82f67cd9 IM |
137 | config TIMER_STATS |
138 | bool "Collect kernel timers statistics" | |
139 | depends on DEBUG_KERNEL && PROC_FS | |
140 | help | |
141 | If you say Y here, additional code will be inserted into the | |
142 | timer routines to collect statistics about kernel timers being | |
143 | reprogrammed. The statistics can be read from /proc/timer_stats. | |
144 | The statistics collection is started by writing 1 to /proc/timer_stats, | |
145 | writing 0 stops it. This feature is useful to collect information | |
146 | about timer usage patterns in kernel and userspace. | |
147 | ||
1da177e4 | 148 | config DEBUG_SLAB |
4a2f0acf | 149 | bool "Debug slab memory allocations" |
50dd26ba | 150 | depends on DEBUG_KERNEL && SLAB |
1da177e4 LT |
151 | help |
152 | Say Y here to have the kernel do limited verification on memory | |
153 | allocation as well as poisoning memory on free to catch use of freed | |
154 | memory. This can make kmalloc/kfree-intensive workloads much slower. | |
155 | ||
871751e2 AV |
156 | config DEBUG_SLAB_LEAK |
157 | bool "Memory leak debugging" | |
158 | depends on DEBUG_SLAB | |
159 | ||
1da177e4 LT |
160 | config DEBUG_PREEMPT |
161 | bool "Debug preemptible kernel" | |
8637c099 | 162 | depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT |
1da177e4 LT |
163 | default y |
164 | help | |
165 | If you say Y here then the kernel will use a debug variant of the | |
166 | commonly used smp_processor_id() function and will print warnings | |
167 | if kernel code uses it in a preemption-unsafe way. Also, the kernel | |
168 | will detect preemption count underflows. | |
169 | ||
e7eebaf6 IM |
170 | config DEBUG_RT_MUTEXES |
171 | bool "RT Mutex debugging, deadlock detection" | |
e7eebaf6 IM |
172 | depends on DEBUG_KERNEL && RT_MUTEXES |
173 | help | |
174 | This allows rt mutex semantics violations and rt mutex related | |
175 | deadlocks (lockups) to be detected and reported automatically. | |
176 | ||
177 | config DEBUG_PI_LIST | |
178 | bool | |
179 | default y | |
180 | depends on DEBUG_RT_MUTEXES | |
181 | ||
61a87122 TG |
182 | config RT_MUTEX_TESTER |
183 | bool "Built-in scriptable tester for rt-mutexes" | |
a1583d3e | 184 | depends on DEBUG_KERNEL && RT_MUTEXES |
61a87122 TG |
185 | help |
186 | This option enables a rt-mutex tester. | |
187 | ||
1da177e4 | 188 | config DEBUG_SPINLOCK |
4d9f34ad | 189 | bool "Spinlock and rw-lock debugging: basic checks" |
1da177e4 LT |
190 | depends on DEBUG_KERNEL |
191 | help | |
192 | Say Y here and build SMP to catch missing spinlock initialization | |
193 | and certain other kinds of spinlock errors commonly made. This is | |
194 | best used in conjunction with the NMI watchdog so that spinlock | |
195 | deadlocks are also debuggable. | |
196 | ||
4d9f34ad IM |
197 | config DEBUG_MUTEXES |
198 | bool "Mutex debugging: basic checks" | |
199 | depends on DEBUG_KERNEL | |
200 | help | |
201 | This feature allows mutex semantics violations to be detected and | |
202 | reported. | |
203 | ||
4d9f34ad IM |
204 | config DEBUG_LOCK_ALLOC |
205 | bool "Lock debugging: detect incorrect freeing of live locks" | |
517e7aa5 | 206 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
207 | select DEBUG_SPINLOCK |
208 | select DEBUG_MUTEXES | |
4d9f34ad IM |
209 | select LOCKDEP |
210 | help | |
211 | This feature will check whether any held lock (spinlock, rwlock, | |
212 | mutex or rwsem) is incorrectly freed by the kernel, via any of the | |
213 | memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), | |
214 | vfree(), etc.), whether a live lock is incorrectly reinitialized via | |
215 | spin_lock_init()/mutex_init()/etc., or whether there is any lock | |
216 | held during task exit. | |
217 | ||
218 | config PROVE_LOCKING | |
219 | bool "Lock debugging: prove locking correctness" | |
517e7aa5 | 220 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad IM |
221 | select LOCKDEP |
222 | select DEBUG_SPINLOCK | |
223 | select DEBUG_MUTEXES | |
4d9f34ad IM |
224 | select DEBUG_LOCK_ALLOC |
225 | default n | |
226 | help | |
227 | This feature enables the kernel to prove that all locking | |
228 | that occurs in the kernel runtime is mathematically | |
229 | correct: that under no circumstance could an arbitrary (and | |
230 | not yet triggered) combination of observed locking | |
231 | sequences (on an arbitrary number of CPUs, running an | |
232 | arbitrary number of tasks and interrupt contexts) cause a | |
233 | deadlock. | |
234 | ||
235 | In short, this feature enables the kernel to report locking | |
236 | related deadlocks before they actually occur. | |
237 | ||
238 | The proof does not depend on how hard and complex a | |
239 | deadlock scenario would be to trigger: how many | |
240 | participant CPUs, tasks and irq-contexts would be needed | |
241 | for it to trigger. The proof also does not depend on | |
242 | timing: if a race and a resulting deadlock is possible | |
243 | theoretically (no matter how unlikely the race scenario | |
244 | is), it will be proven so and will immediately be | |
245 | reported by the kernel (once the event is observed that | |
246 | makes the deadlock theoretically possible). | |
247 | ||
248 | If a deadlock is impossible (i.e. the locking rules, as | |
249 | observed by the kernel, are mathematically correct), the | |
250 | kernel reports nothing. | |
251 | ||
252 | NOTE: this feature can also be enabled for rwlocks, mutexes | |
253 | and rwsems - in which case all dependencies between these | |
254 | different locking variants are observed and mapped too, and | |
255 | the proof of observed correctness is also maintained for an | |
256 | arbitrary combination of these separate locking variants. | |
257 | ||
258 | For more details, see Documentation/lockdep-design.txt. | |
259 | ||
260 | config LOCKDEP | |
261 | bool | |
517e7aa5 | 262 | depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT |
4d9f34ad | 263 | select STACKTRACE |
14cf232a | 264 | select FRAME_POINTER if !X86 && !MIPS |
4d9f34ad IM |
265 | select KALLSYMS |
266 | select KALLSYMS_ALL | |
267 | ||
268 | config DEBUG_LOCKDEP | |
269 | bool "Lock dependency engine debugging" | |
517e7aa5 | 270 | depends on DEBUG_KERNEL && LOCKDEP |
4d9f34ad IM |
271 | help |
272 | If you say Y here, the lock dependency engine will do | |
273 | additional runtime checks to debug itself, at the price | |
274 | of more runtime overhead. | |
275 | ||
276 | config TRACE_IRQFLAGS | |
517e7aa5 | 277 | depends on DEBUG_KERNEL |
4d9f34ad IM |
278 | bool |
279 | default y | |
280 | depends on TRACE_IRQFLAGS_SUPPORT | |
281 | depends on PROVE_LOCKING | |
282 | ||
1da177e4 | 283 | config DEBUG_SPINLOCK_SLEEP |
4d9f34ad | 284 | bool "Spinlock debugging: sleep-inside-spinlock checking" |
1da177e4 LT |
285 | depends on DEBUG_KERNEL |
286 | help | |
287 | If you say Y here, various routines which may sleep will become very | |
288 | noisy if they are called with a spinlock held. | |
289 | ||
cae2ed9a IM |
290 | config DEBUG_LOCKING_API_SELFTESTS |
291 | bool "Locking API boot-time self-tests" | |
292 | depends on DEBUG_KERNEL | |
293 | help | |
294 | Say Y here if you want the kernel to run a short self-test during | |
295 | bootup. The self-test checks whether common types of locking bugs | |
296 | are detected by debugging mechanisms or not. (if you disable | |
297 | lock debugging then those bugs wont be detected of course.) | |
298 | The following locking APIs are covered: spinlocks, rwlocks, | |
299 | mutexes and rwsems. | |
300 | ||
8637c099 IM |
301 | config STACKTRACE |
302 | bool | |
517e7aa5 | 303 | depends on DEBUG_KERNEL |
8637c099 IM |
304 | depends on STACKTRACE_SUPPORT |
305 | ||
1da177e4 LT |
306 | config DEBUG_KOBJECT |
307 | bool "kobject debugging" | |
308 | depends on DEBUG_KERNEL | |
309 | help | |
310 | If you say Y here, some extra kobject debugging messages will be sent | |
311 | to the syslog. | |
312 | ||
313 | config DEBUG_HIGHMEM | |
314 | bool "Highmem debugging" | |
315 | depends on DEBUG_KERNEL && HIGHMEM | |
316 | help | |
317 | This options enables addition error checking for high memory systems. | |
318 | Disable for production systems. | |
319 | ||
320 | config DEBUG_BUGVERBOSE | |
321 | bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED | |
c8538a7a | 322 | depends on BUG |
1394f032 | 323 | depends on ARM || ARM26 || AVR32 || M32R || M68K || SPARC32 || SPARC64 || FRV || SUPERH || GENERIC_BUG || BFIN |
1da177e4 LT |
324 | default !EMBEDDED |
325 | help | |
326 | Say Y here to make BUG() panics output the file name and line number | |
327 | of the BUG call as well as the EIP and oops trace. This aids | |
328 | debugging but costs about 70-100K of memory. | |
329 | ||
330 | config DEBUG_INFO | |
331 | bool "Compile the kernel with debug info" | |
332 | depends on DEBUG_KERNEL | |
333 | help | |
334 | If you say Y here the resulting kernel image will include | |
335 | debugging info resulting in a larger kernel image. | |
b72e53f8 AD |
336 | This adds debug symbols to the kernel and modules (gcc -g), and |
337 | is needed if you intend to use kernel crashdump or binary object | |
338 | tools like crash, kgdb, LKCD, gdb, etc on the kernel. | |
1da177e4 LT |
339 | Say Y here only if you plan to debug the kernel. |
340 | ||
341 | If unsure, say N. | |
342 | ||
a241ec65 PM |
343 | config DEBUG_VM |
344 | bool "Debug VM" | |
345 | depends on DEBUG_KERNEL | |
346 | help | |
13e7444b NP |
347 | Enable this to turn on extended checks in the virtual-memory system |
348 | that may impact performance. | |
a241ec65 PM |
349 | |
350 | If unsure, say N. | |
351 | ||
199a9afc DJ |
352 | config DEBUG_LIST |
353 | bool "Debug linked list manipulation" | |
354 | depends on DEBUG_KERNEL | |
355 | help | |
356 | Enable this to turn on extended checks in the linked-list | |
357 | walking routines. | |
358 | ||
359 | If unsure, say N. | |
360 | ||
1da177e4 LT |
361 | config FRAME_POINTER |
362 | bool "Compile the kernel with frame pointers" | |
1394f032 | 363 | depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML || S390 || AVR32 || SUPERH || BFIN) |
37fce857 | 364 | default y if DEBUG_INFO && UML |
1da177e4 LT |
365 | help |
366 | If you say Y here the resulting kernel image will be slightly larger | |
2a38bccd JJ |
367 | and slower, but it might give very useful debugging information on |
368 | some architectures or if you use external debuggers. | |
aeb39986 | 369 | If you don't debug the kernel, you can say N. |
1da177e4 | 370 | |
a9df3d0f IM |
371 | config FORCED_INLINING |
372 | bool "Force gcc to inline functions marked 'inline'" | |
373 | depends on DEBUG_KERNEL | |
374 | default y | |
375 | help | |
376 | This option determines if the kernel forces gcc to inline the functions | |
377 | developers have marked 'inline'. Doing so takes away freedom from gcc to | |
378 | do what it thinks is best, which is desirable for the gcc 3.x series of | |
379 | compilers. The gcc 4.x series have a rewritten inlining algorithm and | |
380 | disabling this option will generate a smaller kernel there. Hopefully | |
381 | this algorithm is so good that allowing gcc4 to make the decision can | |
382 | become the default in the future, until then this option is there to | |
383 | test gcc for this. | |
384 | ||
a241ec65 PM |
385 | config RCU_TORTURE_TEST |
386 | tristate "torture tests for RCU" | |
387 | depends on DEBUG_KERNEL | |
388 | default n | |
389 | help | |
390 | This option provides a kernel module that runs torture tests | |
391 | on the RCU infrastructure. The kernel module may be built | |
392 | after the fact on the running kernel to be tested, if desired. | |
393 | ||
394 | Say Y here if you want RCU torture tests to start automatically | |
395 | at boot time (you probably don't). | |
396 | Say M if you want the RCU torture tests to build as a module. | |
397 | Say N if you are unsure. | |
8bb31b9d AG |
398 | |
399 | config LKDTM | |
400 | tristate "Linux Kernel Dump Test Tool Module" | |
bf4735a4 | 401 | depends on DEBUG_KERNEL |
8bb31b9d AG |
402 | depends on KPROBES |
403 | default n | |
404 | help | |
405 | This module enables testing of the different dumping mechanisms by | |
406 | inducing system failures at predefined crash points. | |
407 | If you don't need it: say N | |
408 | Choose M here to compile this code as a module. The module will be | |
409 | called lkdtm. | |
410 | ||
411 | Documentation on how to use the module can be found in | |
412 | drivers/misc/lkdtm.c | |
6ff1cb35 AM |
413 | |
414 | config FAULT_INJECTION | |
1ab8509a AM |
415 | bool "Fault-injection framework" |
416 | depends on DEBUG_KERNEL | |
329409ae AM |
417 | help |
418 | Provide fault-injection framework. | |
419 | For more details, see Documentation/fault-injection/. | |
6ff1cb35 | 420 | |
8a8b6502 | 421 | config FAILSLAB |
1ab8509a AM |
422 | bool "Fault-injection capability for kmalloc" |
423 | depends on FAULT_INJECTION | |
8a8b6502 | 424 | help |
1ab8509a | 425 | Provide fault-injection capability for kmalloc. |
8a8b6502 | 426 | |
933e312e AM |
427 | config FAIL_PAGE_ALLOC |
428 | bool "Fault-injection capabilitiy for alloc_pages()" | |
1ab8509a | 429 | depends on FAULT_INJECTION |
933e312e | 430 | help |
1ab8509a | 431 | Provide fault-injection capability for alloc_pages(). |
933e312e | 432 | |
c17bb495 | 433 | config FAIL_MAKE_REQUEST |
86327d19 | 434 | bool "Fault-injection capability for disk IO" |
1ab8509a | 435 | depends on FAULT_INJECTION |
c17bb495 | 436 | help |
1ab8509a | 437 | Provide fault-injection capability for disk IO. |
c17bb495 | 438 | |
6ff1cb35 AM |
439 | config FAULT_INJECTION_DEBUG_FS |
440 | bool "Debugfs entries for fault-injection capabilities" | |
1ab8509a | 441 | depends on FAULT_INJECTION && SYSFS && DEBUG_FS |
6ff1cb35 | 442 | help |
1ab8509a | 443 | Enable configuration of fault-injection capabilities via debugfs. |
1df49008 AM |
444 | |
445 | config FAULT_INJECTION_STACKTRACE_FILTER | |
446 | bool "stacktrace filter for fault-injection capabilities" | |
447 | depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT | |
448 | select STACKTRACE | |
449 | select FRAME_POINTER | |
450 | help | |
451 | Provide stacktrace filter for fault-injection capabilities |