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Commit 89d7ce2a2178e7f562f608b466a18c8c2ece87af

Authored by Frederic Weisbecker
1 parent d7c547335f
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

lockup_detector: Make BOOTPARAM_SOFTLOCKUP_PANIC depend on LOCKUP_DETECTOR 

Panic on softlockups was still depending on the softlockup detector.
But the latter has been merged into the lockup detector now.

Let's update this config dependency.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>

Showing 1 changed file with 1 additions and 1 deletions Inline Diff

1 1
2 config PRINTK_TIME 2 config PRINTK_TIME
3 bool "Show timing information on printks" 3 bool "Show timing information on printks"
4 depends on PRINTK 4 depends on PRINTK
5 help 5 help
6 Selecting this option causes timing information to be 6 Selecting this option causes timing information to be
7 included in printk output. This allows you to measure 7 included in printk output. This allows you to measure
8 the interval between kernel operations, including bootup 8 the interval between kernel operations, including bootup
9 operations. This is useful for identifying long delays 9 operations. This is useful for identifying long delays
10 in kernel startup. 10 in kernel startup.
11 11
12 config ENABLE_WARN_DEPRECATED 12 config ENABLE_WARN_DEPRECATED
13 bool "Enable __deprecated logic" 13 bool "Enable __deprecated logic"
14 default y 14 default y
15 help 15 help
16 Enable the __deprecated logic in the kernel build. 16 Enable the __deprecated logic in the kernel build.
17 Disable this to suppress the "warning: 'foo' is deprecated 17 Disable this to suppress the "warning: 'foo' is deprecated
18 (declared at kernel/power/somefile.c:1234)" messages. 18 (declared at kernel/power/somefile.c:1234)" messages.
19 19
20 config ENABLE_MUST_CHECK 20 config ENABLE_MUST_CHECK
21 bool "Enable __must_check logic" 21 bool "Enable __must_check logic"
22 default y 22 default y
23 help 23 help
24 Enable the __must_check logic in the kernel build. Disable this to 24 Enable the __must_check logic in the kernel build. Disable this to
25 suppress the "warning: ignoring return value of 'foo', declared with 25 suppress the "warning: ignoring return value of 'foo', declared with
26 attribute warn_unused_result" messages. 26 attribute warn_unused_result" messages.
27 27
28 config FRAME_WARN 28 config FRAME_WARN
29 int "Warn for stack frames larger than (needs gcc 4.4)" 29 int "Warn for stack frames larger than (needs gcc 4.4)"
30 range 0 8192 30 range 0 8192
31 default 1024 if !64BIT 31 default 1024 if !64BIT
32 default 2048 if 64BIT 32 default 2048 if 64BIT
33 help 33 help
34 Tell gcc to warn at build time for stack frames larger than this. 34 Tell gcc to warn at build time for stack frames larger than this.
35 Setting this too low will cause a lot of warnings. 35 Setting this too low will cause a lot of warnings.
36 Setting it to 0 disables the warning. 36 Setting it to 0 disables the warning.
37 Requires gcc 4.4 37 Requires gcc 4.4
38 38
39 config MAGIC_SYSRQ 39 config MAGIC_SYSRQ
40 bool "Magic SysRq key" 40 bool "Magic SysRq key"
41 depends on !UML 41 depends on !UML
42 help 42 help
43 If you say Y here, you will have some control over the system even 43 If you say Y here, you will have some control over the system even
44 if the system crashes for example during kernel debugging (e.g., you 44 if the system crashes for example during kernel debugging (e.g., you
45 will be able to flush the buffer cache to disk, reboot the system 45 will be able to flush the buffer cache to disk, reboot the system
46 immediately or dump some status information). This is accomplished 46 immediately or dump some status information). This is accomplished
47 by pressing various keys while holding SysRq (Alt+PrintScreen). It 47 by pressing various keys while holding SysRq (Alt+PrintScreen). It
48 also works on a serial console (on PC hardware at least), if you 48 also works on a serial console (on PC hardware at least), if you
49 send a BREAK and then within 5 seconds a command keypress. The 49 send a BREAK and then within 5 seconds a command keypress. The
50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y 50 keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
51 unless you really know what this hack does. 51 unless you really know what this hack does.
52 52
53 config STRIP_ASM_SYMS 53 config STRIP_ASM_SYMS
54 bool "Strip assembler-generated symbols during link" 54 bool "Strip assembler-generated symbols during link"
55 default n 55 default n
56 help 56 help
57 Strip internal assembler-generated symbols during a link (symbols 57 Strip internal assembler-generated symbols during a link (symbols
58 that look like '.Lxxx') so they don't pollute the output of 58 that look like '.Lxxx') so they don't pollute the output of
59 get_wchan() and suchlike. 59 get_wchan() and suchlike.
60 60
61 config UNUSED_SYMBOLS 61 config UNUSED_SYMBOLS
62 bool "Enable unused/obsolete exported symbols" 62 bool "Enable unused/obsolete exported symbols"
63 default y if X86 63 default y if X86
64 help 64 help
65 Unused but exported symbols make the kernel needlessly bigger. For 65 Unused but exported symbols make the kernel needlessly bigger. For
66 that reason most of these unused exports will soon be removed. This 66 that reason most of these unused exports will soon be removed. This
67 option is provided temporarily to provide a transition period in case 67 option is provided temporarily to provide a transition period in case
68 some external kernel module needs one of these symbols anyway. If you 68 some external kernel module needs one of these symbols anyway. If you
69 encounter such a case in your module, consider if you are actually 69 encounter such a case in your module, consider if you are actually
70 using the right API. (rationale: since nobody in the kernel is using 70 using the right API. (rationale: since nobody in the kernel is using
71 this in a module, there is a pretty good chance it's actually the 71 this in a module, there is a pretty good chance it's actually the
72 wrong interface to use). If you really need the symbol, please send a 72 wrong interface to use). If you really need the symbol, please send a
73 mail to the linux kernel mailing list mentioning the symbol and why 73 mail to the linux kernel mailing list mentioning the symbol and why
74 you really need it, and what the merge plan to the mainline kernel for 74 you really need it, and what the merge plan to the mainline kernel for
75 your module is. 75 your module is.
76 76
77 config DEBUG_FS 77 config DEBUG_FS
78 bool "Debug Filesystem" 78 bool "Debug Filesystem"
79 depends on SYSFS 79 depends on SYSFS
80 help 80 help
81 debugfs is a virtual file system that kernel developers use to put 81 debugfs is a virtual file system that kernel developers use to put
82 debugging files into. Enable this option to be able to read and 82 debugging files into. Enable this option to be able to read and
83 write to these files. 83 write to these files.
84 84
85 For detailed documentation on the debugfs API, see 85 For detailed documentation on the debugfs API, see
86 Documentation/DocBook/filesystems. 86 Documentation/DocBook/filesystems.
87 87
88 If unsure, say N. 88 If unsure, say N.
89 89
90 config HEADERS_CHECK 90 config HEADERS_CHECK
91 bool "Run 'make headers_check' when building vmlinux" 91 bool "Run 'make headers_check' when building vmlinux"
92 depends on !UML 92 depends on !UML
93 help 93 help
94 This option will extract the user-visible kernel headers whenever 94 This option will extract the user-visible kernel headers whenever
95 building the kernel, and will run basic sanity checks on them to 95 building the kernel, and will run basic sanity checks on them to
96 ensure that exported files do not attempt to include files which 96 ensure that exported files do not attempt to include files which
97 were not exported, etc. 97 were not exported, etc.
98 98
99 If you're making modifications to header files which are 99 If you're making modifications to header files which are
100 relevant for userspace, say 'Y', and check the headers 100 relevant for userspace, say 'Y', and check the headers
101 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in 101 exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in
102 your build tree), to make sure they're suitable. 102 your build tree), to make sure they're suitable.
103 103
104 config DEBUG_SECTION_MISMATCH 104 config DEBUG_SECTION_MISMATCH
105 bool "Enable full Section mismatch analysis" 105 bool "Enable full Section mismatch analysis"
106 depends on UNDEFINED || (BLACKFIN) 106 depends on UNDEFINED || (BLACKFIN)
107 default y 107 default y
108 # This option is on purpose disabled for now. 108 # This option is on purpose disabled for now.
109 # It will be enabled when we are down to a reasonable number 109 # It will be enabled when we are down to a reasonable number
110 # of section mismatch warnings (< 10 for an allyesconfig build) 110 # of section mismatch warnings (< 10 for an allyesconfig build)
111 help 111 help
112 The section mismatch analysis checks if there are illegal 112 The section mismatch analysis checks if there are illegal
113 references from one section to another section. 113 references from one section to another section.
114 Linux will during link or during runtime drop some sections 114 Linux will during link or during runtime drop some sections
115 and any use of code/data previously in these sections will 115 and any use of code/data previously in these sections will
116 most likely result in an oops. 116 most likely result in an oops.
117 In the code functions and variables are annotated with 117 In the code functions and variables are annotated with
118 __init, __devinit etc. (see full list in include/linux/init.h) 118 __init, __devinit etc. (see full list in include/linux/init.h)
119 which results in the code/data being placed in specific sections. 119 which results in the code/data being placed in specific sections.
120 The section mismatch analysis is always done after a full 120 The section mismatch analysis is always done after a full
121 kernel build but enabling this option will in addition 121 kernel build but enabling this option will in addition
122 do the following: 122 do the following:
123 - Add the option -fno-inline-functions-called-once to gcc 123 - Add the option -fno-inline-functions-called-once to gcc
124 When inlining a function annotated __init in a non-init 124 When inlining a function annotated __init in a non-init
125 function we would lose the section information and thus 125 function we would lose the section information and thus
126 the analysis would not catch the illegal reference. 126 the analysis would not catch the illegal reference.
127 This option tells gcc to inline less but will also 127 This option tells gcc to inline less but will also
128 result in a larger kernel. 128 result in a larger kernel.
129 - Run the section mismatch analysis for each module/built-in.o 129 - Run the section mismatch analysis for each module/built-in.o
130 When we run the section mismatch analysis on vmlinux.o we 130 When we run the section mismatch analysis on vmlinux.o we
131 lose valueble information about where the mismatch was 131 lose valueble information about where the mismatch was
132 introduced. 132 introduced.
133 Running the analysis for each module/built-in.o file 133 Running the analysis for each module/built-in.o file
134 will tell where the mismatch happens much closer to the 134 will tell where the mismatch happens much closer to the
135 source. The drawback is that we will report the same 135 source. The drawback is that we will report the same
136 mismatch at least twice. 136 mismatch at least twice.
137 - Enable verbose reporting from modpost to help solving 137 - Enable verbose reporting from modpost to help solving
138 the section mismatches reported. 138 the section mismatches reported.
139 139
140 config DEBUG_KERNEL 140 config DEBUG_KERNEL
141 bool "Kernel debugging" 141 bool "Kernel debugging"
142 help 142 help
143 Say Y here if you are developing drivers or trying to debug and 143 Say Y here if you are developing drivers or trying to debug and
144 identify kernel problems. 144 identify kernel problems.
145 145
146 config DEBUG_SHIRQ 146 config DEBUG_SHIRQ
147 bool "Debug shared IRQ handlers" 147 bool "Debug shared IRQ handlers"
148 depends on DEBUG_KERNEL && GENERIC_HARDIRQS 148 depends on DEBUG_KERNEL && GENERIC_HARDIRQS
149 help 149 help
150 Enable this to generate a spurious interrupt as soon as a shared 150 Enable this to generate a spurious interrupt as soon as a shared
151 interrupt handler is registered, and just before one is deregistered. 151 interrupt handler is registered, and just before one is deregistered.
152 Drivers ought to be able to handle interrupts coming in at those 152 Drivers ought to be able to handle interrupts coming in at those
153 points; some don't and need to be caught. 153 points; some don't and need to be caught.
154 154
155 config DETECT_SOFTLOCKUP 155 config DETECT_SOFTLOCKUP
156 bool 156 bool
157 depends on DEBUG_KERNEL && !S390 157 depends on DEBUG_KERNEL && !S390
158 default y 158 default y
159 help 159 help
160 Say Y here to enable the kernel to detect "soft lockups", 160 Say Y here to enable the kernel to detect "soft lockups",
161 which are bugs that cause the kernel to loop in kernel 161 which are bugs that cause the kernel to loop in kernel
162 mode for more than 60 seconds, without giving other tasks a 162 mode for more than 60 seconds, without giving other tasks a
163 chance to run. 163 chance to run.
164 164
165 When a soft-lockup is detected, the kernel will print the 165 When a soft-lockup is detected, the kernel will print the
166 current stack trace (which you should report), but the 166 current stack trace (which you should report), but the
167 system will stay locked up. This feature has negligible 167 system will stay locked up. This feature has negligible
168 overhead. 168 overhead.
169 169
170 (Note that "hard lockups" are separate type of bugs that 170 (Note that "hard lockups" are separate type of bugs that
171 can be detected via the NMI-watchdog, on platforms that 171 can be detected via the NMI-watchdog, on platforms that
172 support it.) 172 support it.)
173 173
174 config LOCKUP_DETECTOR 174 config LOCKUP_DETECTOR
175 bool "Detect Hard and Soft Lockups" 175 bool "Detect Hard and Soft Lockups"
176 depends on DEBUG_KERNEL 176 depends on DEBUG_KERNEL
177 default DETECT_SOFTLOCKUP 177 default DETECT_SOFTLOCKUP
178 help 178 help
179 Say Y here to enable the kernel to act as a watchdog to detect 179 Say Y here to enable the kernel to act as a watchdog to detect
180 hard and soft lockups. 180 hard and soft lockups.
181 181
182 Softlockups are bugs that cause the kernel to loop in kernel 182 Softlockups are bugs that cause the kernel to loop in kernel
183 mode for more than 60 seconds, without giving other tasks a 183 mode for more than 60 seconds, without giving other tasks a
184 chance to run. The current stack trace is displayed upon 184 chance to run. The current stack trace is displayed upon
185 detection and the system will stay locked up. 185 detection and the system will stay locked up.
186 186
187 Hardlockups are bugs that cause the CPU to loop in kernel mode 187 Hardlockups are bugs that cause the CPU to loop in kernel mode
188 for more than 60 seconds, without letting other interrupts have a 188 for more than 60 seconds, without letting other interrupts have a
189 chance to run. The current stack trace is displayed upon detection 189 chance to run. The current stack trace is displayed upon detection
190 and the system will stay locked up. 190 and the system will stay locked up.
191 191
192 The overhead should be minimal. A periodic hrtimer runs to 192 The overhead should be minimal. A periodic hrtimer runs to
193 generate interrupts and kick the watchdog task every 10-12 seconds. 193 generate interrupts and kick the watchdog task every 10-12 seconds.
194 An NMI is generated every 60 seconds or so to check for hardlockups. 194 An NMI is generated every 60 seconds or so to check for hardlockups.
195 195
196 config BOOTPARAM_SOFTLOCKUP_PANIC 196 config BOOTPARAM_SOFTLOCKUP_PANIC
197 bool "Panic (Reboot) On Soft Lockups" 197 bool "Panic (Reboot) On Soft Lockups"
198 depends on DETECT_SOFTLOCKUP 198 depends on LOCKUP_DETECTOR
199 help 199 help
200 Say Y here to enable the kernel to panic on "soft lockups", 200 Say Y here to enable the kernel to panic on "soft lockups",
201 which are bugs that cause the kernel to loop in kernel 201 which are bugs that cause the kernel to loop in kernel
202 mode for more than 60 seconds, without giving other tasks a 202 mode for more than 60 seconds, without giving other tasks a
203 chance to run. 203 chance to run.
204 204
205 The panic can be used in combination with panic_timeout, 205 The panic can be used in combination with panic_timeout,
206 to cause the system to reboot automatically after a 206 to cause the system to reboot automatically after a
207 lockup has been detected. This feature is useful for 207 lockup has been detected. This feature is useful for
208 high-availability systems that have uptime guarantees and 208 high-availability systems that have uptime guarantees and
209 where a lockup must be resolved ASAP. 209 where a lockup must be resolved ASAP.
210 210
211 Say N if unsure. 211 Say N if unsure.
212 212
213 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE 213 config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE
214 int 214 int
215 depends on DETECT_SOFTLOCKUP 215 depends on DETECT_SOFTLOCKUP
216 range 0 1 216 range 0 1
217 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC 217 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
218 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC 218 default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
219 219
220 config DETECT_HUNG_TASK 220 config DETECT_HUNG_TASK
221 bool "Detect Hung Tasks" 221 bool "Detect Hung Tasks"
222 depends on DEBUG_KERNEL 222 depends on DEBUG_KERNEL
223 default DETECT_SOFTLOCKUP 223 default DETECT_SOFTLOCKUP
224 help 224 help
225 Say Y here to enable the kernel to detect "hung tasks", 225 Say Y here to enable the kernel to detect "hung tasks",
226 which are bugs that cause the task to be stuck in 226 which are bugs that cause the task to be stuck in
227 uninterruptible "D" state indefinitiley. 227 uninterruptible "D" state indefinitiley.
228 228
229 When a hung task is detected, the kernel will print the 229 When a hung task is detected, the kernel will print the
230 current stack trace (which you should report), but the 230 current stack trace (which you should report), but the
231 task will stay in uninterruptible state. If lockdep is 231 task will stay in uninterruptible state. If lockdep is
232 enabled then all held locks will also be reported. This 232 enabled then all held locks will also be reported. This
233 feature has negligible overhead. 233 feature has negligible overhead.
234 234
235 config BOOTPARAM_HUNG_TASK_PANIC 235 config BOOTPARAM_HUNG_TASK_PANIC
236 bool "Panic (Reboot) On Hung Tasks" 236 bool "Panic (Reboot) On Hung Tasks"
237 depends on DETECT_HUNG_TASK 237 depends on DETECT_HUNG_TASK
238 help 238 help
239 Say Y here to enable the kernel to panic on "hung tasks", 239 Say Y here to enable the kernel to panic on "hung tasks",
240 which are bugs that cause the kernel to leave a task stuck 240 which are bugs that cause the kernel to leave a task stuck
241 in uninterruptible "D" state. 241 in uninterruptible "D" state.
242 242
243 The panic can be used in combination with panic_timeout, 243 The panic can be used in combination with panic_timeout,
244 to cause the system to reboot automatically after a 244 to cause the system to reboot automatically after a
245 hung task has been detected. This feature is useful for 245 hung task has been detected. This feature is useful for
246 high-availability systems that have uptime guarantees and 246 high-availability systems that have uptime guarantees and
247 where a hung tasks must be resolved ASAP. 247 where a hung tasks must be resolved ASAP.
248 248
249 Say N if unsure. 249 Say N if unsure.
250 250
251 config BOOTPARAM_HUNG_TASK_PANIC_VALUE 251 config BOOTPARAM_HUNG_TASK_PANIC_VALUE
252 int 252 int
253 depends on DETECT_HUNG_TASK 253 depends on DETECT_HUNG_TASK
254 range 0 1 254 range 0 1
255 default 0 if !BOOTPARAM_HUNG_TASK_PANIC 255 default 0 if !BOOTPARAM_HUNG_TASK_PANIC
256 default 1 if BOOTPARAM_HUNG_TASK_PANIC 256 default 1 if BOOTPARAM_HUNG_TASK_PANIC
257 257
258 config SCHED_DEBUG 258 config SCHED_DEBUG
259 bool "Collect scheduler debugging info" 259 bool "Collect scheduler debugging info"
260 depends on DEBUG_KERNEL && PROC_FS 260 depends on DEBUG_KERNEL && PROC_FS
261 default y 261 default y
262 help 262 help
263 If you say Y here, the /proc/sched_debug file will be provided 263 If you say Y here, the /proc/sched_debug file will be provided
264 that can help debug the scheduler. The runtime overhead of this 264 that can help debug the scheduler. The runtime overhead of this
265 option is minimal. 265 option is minimal.
266 266
267 config SCHEDSTATS 267 config SCHEDSTATS
268 bool "Collect scheduler statistics" 268 bool "Collect scheduler statistics"
269 depends on DEBUG_KERNEL && PROC_FS 269 depends on DEBUG_KERNEL && PROC_FS
270 help 270 help
271 If you say Y here, additional code will be inserted into the 271 If you say Y here, additional code will be inserted into the
272 scheduler and related routines to collect statistics about 272 scheduler and related routines to collect statistics about
273 scheduler behavior and provide them in /proc/schedstat. These 273 scheduler behavior and provide them in /proc/schedstat. These
274 stats may be useful for both tuning and debugging the scheduler 274 stats may be useful for both tuning and debugging the scheduler
275 If you aren't debugging the scheduler or trying to tune a specific 275 If you aren't debugging the scheduler or trying to tune a specific
276 application, you can say N to avoid the very slight overhead 276 application, you can say N to avoid the very slight overhead
277 this adds. 277 this adds.
278 278
279 config TIMER_STATS 279 config TIMER_STATS
280 bool "Collect kernel timers statistics" 280 bool "Collect kernel timers statistics"
281 depends on DEBUG_KERNEL && PROC_FS 281 depends on DEBUG_KERNEL && PROC_FS
282 help 282 help
283 If you say Y here, additional code will be inserted into the 283 If you say Y here, additional code will be inserted into the
284 timer routines to collect statistics about kernel timers being 284 timer routines to collect statistics about kernel timers being
285 reprogrammed. The statistics can be read from /proc/timer_stats. 285 reprogrammed. The statistics can be read from /proc/timer_stats.
286 The statistics collection is started by writing 1 to /proc/timer_stats, 286 The statistics collection is started by writing 1 to /proc/timer_stats,
287 writing 0 stops it. This feature is useful to collect information 287 writing 0 stops it. This feature is useful to collect information
288 about timer usage patterns in kernel and userspace. This feature 288 about timer usage patterns in kernel and userspace. This feature
289 is lightweight if enabled in the kernel config but not activated 289 is lightweight if enabled in the kernel config but not activated
290 (it defaults to deactivated on bootup and will only be activated 290 (it defaults to deactivated on bootup and will only be activated
291 if some application like powertop activates it explicitly). 291 if some application like powertop activates it explicitly).
292 292
293 config DEBUG_OBJECTS 293 config DEBUG_OBJECTS
294 bool "Debug object operations" 294 bool "Debug object operations"
295 depends on DEBUG_KERNEL 295 depends on DEBUG_KERNEL
296 help 296 help
297 If you say Y here, additional code will be inserted into the 297 If you say Y here, additional code will be inserted into the
298 kernel to track the life time of various objects and validate 298 kernel to track the life time of various objects and validate
299 the operations on those objects. 299 the operations on those objects.
300 300
301 config DEBUG_OBJECTS_SELFTEST 301 config DEBUG_OBJECTS_SELFTEST
302 bool "Debug objects selftest" 302 bool "Debug objects selftest"
303 depends on DEBUG_OBJECTS 303 depends on DEBUG_OBJECTS
304 help 304 help
305 This enables the selftest of the object debug code. 305 This enables the selftest of the object debug code.
306 306
307 config DEBUG_OBJECTS_FREE 307 config DEBUG_OBJECTS_FREE
308 bool "Debug objects in freed memory" 308 bool "Debug objects in freed memory"
309 depends on DEBUG_OBJECTS 309 depends on DEBUG_OBJECTS
310 help 310 help
311 This enables checks whether a k/v free operation frees an area 311 This enables checks whether a k/v free operation frees an area
312 which contains an object which has not been deactivated 312 which contains an object which has not been deactivated
313 properly. This can make kmalloc/kfree-intensive workloads 313 properly. This can make kmalloc/kfree-intensive workloads
314 much slower. 314 much slower.
315 315
316 config DEBUG_OBJECTS_TIMERS 316 config DEBUG_OBJECTS_TIMERS
317 bool "Debug timer objects" 317 bool "Debug timer objects"
318 depends on DEBUG_OBJECTS 318 depends on DEBUG_OBJECTS
319 help 319 help
320 If you say Y here, additional code will be inserted into the 320 If you say Y here, additional code will be inserted into the
321 timer routines to track the life time of timer objects and 321 timer routines to track the life time of timer objects and
322 validate the timer operations. 322 validate the timer operations.
323 323
324 config DEBUG_OBJECTS_WORK 324 config DEBUG_OBJECTS_WORK
325 bool "Debug work objects" 325 bool "Debug work objects"
326 depends on DEBUG_OBJECTS 326 depends on DEBUG_OBJECTS
327 help 327 help
328 If you say Y here, additional code will be inserted into the 328 If you say Y here, additional code will be inserted into the
329 work queue routines to track the life time of work objects and 329 work queue routines to track the life time of work objects and
330 validate the work operations. 330 validate the work operations.
331 331
332 config DEBUG_OBJECTS_ENABLE_DEFAULT 332 config DEBUG_OBJECTS_ENABLE_DEFAULT
333 int "debug_objects bootup default value (0-1)" 333 int "debug_objects bootup default value (0-1)"
334 range 0 1 334 range 0 1
335 default "1" 335 default "1"
336 depends on DEBUG_OBJECTS 336 depends on DEBUG_OBJECTS
337 help 337 help
338 Debug objects boot parameter default value 338 Debug objects boot parameter default value
339 339
340 config DEBUG_SLAB 340 config DEBUG_SLAB
341 bool "Debug slab memory allocations" 341 bool "Debug slab memory allocations"
342 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK 342 depends on DEBUG_KERNEL && SLAB && !KMEMCHECK
343 help 343 help
344 Say Y here to have the kernel do limited verification on memory 344 Say Y here to have the kernel do limited verification on memory
345 allocation as well as poisoning memory on free to catch use of freed 345 allocation as well as poisoning memory on free to catch use of freed
346 memory. This can make kmalloc/kfree-intensive workloads much slower. 346 memory. This can make kmalloc/kfree-intensive workloads much slower.
347 347
348 config DEBUG_SLAB_LEAK 348 config DEBUG_SLAB_LEAK
349 bool "Memory leak debugging" 349 bool "Memory leak debugging"
350 depends on DEBUG_SLAB 350 depends on DEBUG_SLAB
351 351
352 config SLUB_DEBUG_ON 352 config SLUB_DEBUG_ON
353 bool "SLUB debugging on by default" 353 bool "SLUB debugging on by default"
354 depends on SLUB && SLUB_DEBUG && !KMEMCHECK 354 depends on SLUB && SLUB_DEBUG && !KMEMCHECK
355 default n 355 default n
356 help 356 help
357 Boot with debugging on by default. SLUB boots by default with 357 Boot with debugging on by default. SLUB boots by default with
358 the runtime debug capabilities switched off. Enabling this is 358 the runtime debug capabilities switched off. Enabling this is
359 equivalent to specifying the "slub_debug" parameter on boot. 359 equivalent to specifying the "slub_debug" parameter on boot.
360 There is no support for more fine grained debug control like 360 There is no support for more fine grained debug control like
361 possible with slub_debug=xxx. SLUB debugging may be switched 361 possible with slub_debug=xxx. SLUB debugging may be switched
362 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying 362 off in a kernel built with CONFIG_SLUB_DEBUG_ON by specifying
363 "slub_debug=-". 363 "slub_debug=-".
364 364
365 config SLUB_STATS 365 config SLUB_STATS
366 default n 366 default n
367 bool "Enable SLUB performance statistics" 367 bool "Enable SLUB performance statistics"
368 depends on SLUB && SLUB_DEBUG && SYSFS 368 depends on SLUB && SLUB_DEBUG && SYSFS
369 help 369 help
370 SLUB statistics are useful to debug SLUBs allocation behavior in 370 SLUB statistics are useful to debug SLUBs allocation behavior in
371 order find ways to optimize the allocator. This should never be 371 order find ways to optimize the allocator. This should never be
372 enabled for production use since keeping statistics slows down 372 enabled for production use since keeping statistics slows down
373 the allocator by a few percentage points. The slabinfo command 373 the allocator by a few percentage points. The slabinfo command
374 supports the determination of the most active slabs to figure 374 supports the determination of the most active slabs to figure
375 out which slabs are relevant to a particular load. 375 out which slabs are relevant to a particular load.
376 Try running: slabinfo -DA 376 Try running: slabinfo -DA
377 377
378 config DEBUG_KMEMLEAK 378 config DEBUG_KMEMLEAK
379 bool "Kernel memory leak detector" 379 bool "Kernel memory leak detector"
380 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \ 380 depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
381 (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE) 381 (X86 || ARM || PPC || S390 || SPARC64 || SUPERH || MICROBLAZE)
382 382
383 select DEBUG_FS if SYSFS 383 select DEBUG_FS if SYSFS
384 select STACKTRACE if STACKTRACE_SUPPORT 384 select STACKTRACE if STACKTRACE_SUPPORT
385 select KALLSYMS 385 select KALLSYMS
386 select CRC32 386 select CRC32
387 help 387 help
388 Say Y here if you want to enable the memory leak 388 Say Y here if you want to enable the memory leak
389 detector. The memory allocation/freeing is traced in a way 389 detector. The memory allocation/freeing is traced in a way
390 similar to the Boehm's conservative garbage collector, the 390 similar to the Boehm's conservative garbage collector, the
391 difference being that the orphan objects are not freed but 391 difference being that the orphan objects are not freed but
392 only shown in /sys/kernel/debug/kmemleak. Enabling this 392 only shown in /sys/kernel/debug/kmemleak. Enabling this
393 feature will introduce an overhead to memory 393 feature will introduce an overhead to memory
394 allocations. See Documentation/kmemleak.txt for more 394 allocations. See Documentation/kmemleak.txt for more
395 details. 395 details.
396 396
397 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances 397 Enabling DEBUG_SLAB or SLUB_DEBUG may increase the chances
398 of finding leaks due to the slab objects poisoning. 398 of finding leaks due to the slab objects poisoning.
399 399
400 In order to access the kmemleak file, debugfs needs to be 400 In order to access the kmemleak file, debugfs needs to be
401 mounted (usually at /sys/kernel/debug). 401 mounted (usually at /sys/kernel/debug).
402 402
403 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE 403 config DEBUG_KMEMLEAK_EARLY_LOG_SIZE
404 int "Maximum kmemleak early log entries" 404 int "Maximum kmemleak early log entries"
405 depends on DEBUG_KMEMLEAK 405 depends on DEBUG_KMEMLEAK
406 range 200 40000 406 range 200 40000
407 default 400 407 default 400
408 help 408 help
409 Kmemleak must track all the memory allocations to avoid 409 Kmemleak must track all the memory allocations to avoid
410 reporting false positives. Since memory may be allocated or 410 reporting false positives. Since memory may be allocated or
411 freed before kmemleak is initialised, an early log buffer is 411 freed before kmemleak is initialised, an early log buffer is
412 used to store these actions. If kmemleak reports "early log 412 used to store these actions. If kmemleak reports "early log
413 buffer exceeded", please increase this value. 413 buffer exceeded", please increase this value.
414 414
415 config DEBUG_KMEMLEAK_TEST 415 config DEBUG_KMEMLEAK_TEST
416 tristate "Simple test for the kernel memory leak detector" 416 tristate "Simple test for the kernel memory leak detector"
417 depends on DEBUG_KMEMLEAK 417 depends on DEBUG_KMEMLEAK
418 help 418 help
419 Say Y or M here to build a test for the kernel memory leak 419 Say Y or M here to build a test for the kernel memory leak
420 detector. This option enables a module that explicitly leaks 420 detector. This option enables a module that explicitly leaks
421 memory. 421 memory.
422 422
423 If unsure, say N. 423 If unsure, say N.
424 424
425 config DEBUG_PREEMPT 425 config DEBUG_PREEMPT
426 bool "Debug preemptible kernel" 426 bool "Debug preemptible kernel"
427 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT 427 depends on DEBUG_KERNEL && PREEMPT && TRACE_IRQFLAGS_SUPPORT
428 default y 428 default y
429 help 429 help
430 If you say Y here then the kernel will use a debug variant of the 430 If you say Y here then the kernel will use a debug variant of the
431 commonly used smp_processor_id() function and will print warnings 431 commonly used smp_processor_id() function and will print warnings
432 if kernel code uses it in a preemption-unsafe way. Also, the kernel 432 if kernel code uses it in a preemption-unsafe way. Also, the kernel
433 will detect preemption count underflows. 433 will detect preemption count underflows.
434 434
435 config DEBUG_RT_MUTEXES 435 config DEBUG_RT_MUTEXES
436 bool "RT Mutex debugging, deadlock detection" 436 bool "RT Mutex debugging, deadlock detection"
437 depends on DEBUG_KERNEL && RT_MUTEXES 437 depends on DEBUG_KERNEL && RT_MUTEXES
438 help 438 help
439 This allows rt mutex semantics violations and rt mutex related 439 This allows rt mutex semantics violations and rt mutex related
440 deadlocks (lockups) to be detected and reported automatically. 440 deadlocks (lockups) to be detected and reported automatically.
441 441
442 config DEBUG_PI_LIST 442 config DEBUG_PI_LIST
443 bool 443 bool
444 default y 444 default y
445 depends on DEBUG_RT_MUTEXES 445 depends on DEBUG_RT_MUTEXES
446 446
447 config RT_MUTEX_TESTER 447 config RT_MUTEX_TESTER
448 bool "Built-in scriptable tester for rt-mutexes" 448 bool "Built-in scriptable tester for rt-mutexes"
449 depends on DEBUG_KERNEL && RT_MUTEXES 449 depends on DEBUG_KERNEL && RT_MUTEXES
450 help 450 help
451 This option enables a rt-mutex tester. 451 This option enables a rt-mutex tester.
452 452
453 config DEBUG_SPINLOCK 453 config DEBUG_SPINLOCK
454 bool "Spinlock and rw-lock debugging: basic checks" 454 bool "Spinlock and rw-lock debugging: basic checks"
455 depends on DEBUG_KERNEL 455 depends on DEBUG_KERNEL
456 help 456 help
457 Say Y here and build SMP to catch missing spinlock initialization 457 Say Y here and build SMP to catch missing spinlock initialization
458 and certain other kinds of spinlock errors commonly made. This is 458 and certain other kinds of spinlock errors commonly made. This is
459 best used in conjunction with the NMI watchdog so that spinlock 459 best used in conjunction with the NMI watchdog so that spinlock
460 deadlocks are also debuggable. 460 deadlocks are also debuggable.
461 461
462 config DEBUG_MUTEXES 462 config DEBUG_MUTEXES
463 bool "Mutex debugging: basic checks" 463 bool "Mutex debugging: basic checks"
464 depends on DEBUG_KERNEL 464 depends on DEBUG_KERNEL
465 help 465 help
466 This feature allows mutex semantics violations to be detected and 466 This feature allows mutex semantics violations to be detected and
467 reported. 467 reported.
468 468
469 config DEBUG_LOCK_ALLOC 469 config DEBUG_LOCK_ALLOC
470 bool "Lock debugging: detect incorrect freeing of live locks" 470 bool "Lock debugging: detect incorrect freeing of live locks"
471 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 471 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
472 select DEBUG_SPINLOCK 472 select DEBUG_SPINLOCK
473 select DEBUG_MUTEXES 473 select DEBUG_MUTEXES
474 select LOCKDEP 474 select LOCKDEP
475 help 475 help
476 This feature will check whether any held lock (spinlock, rwlock, 476 This feature will check whether any held lock (spinlock, rwlock,
477 mutex or rwsem) is incorrectly freed by the kernel, via any of the 477 mutex or rwsem) is incorrectly freed by the kernel, via any of the
478 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(), 478 memory-freeing routines (kfree(), kmem_cache_free(), free_pages(),
479 vfree(), etc.), whether a live lock is incorrectly reinitialized via 479 vfree(), etc.), whether a live lock is incorrectly reinitialized via
480 spin_lock_init()/mutex_init()/etc., or whether there is any lock 480 spin_lock_init()/mutex_init()/etc., or whether there is any lock
481 held during task exit. 481 held during task exit.
482 482
483 config PROVE_LOCKING 483 config PROVE_LOCKING
484 bool "Lock debugging: prove locking correctness" 484 bool "Lock debugging: prove locking correctness"
485 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 485 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
486 select LOCKDEP 486 select LOCKDEP
487 select DEBUG_SPINLOCK 487 select DEBUG_SPINLOCK
488 select DEBUG_MUTEXES 488 select DEBUG_MUTEXES
489 select DEBUG_LOCK_ALLOC 489 select DEBUG_LOCK_ALLOC
490 default n 490 default n
491 help 491 help
492 This feature enables the kernel to prove that all locking 492 This feature enables the kernel to prove that all locking
493 that occurs in the kernel runtime is mathematically 493 that occurs in the kernel runtime is mathematically
494 correct: that under no circumstance could an arbitrary (and 494 correct: that under no circumstance could an arbitrary (and
495 not yet triggered) combination of observed locking 495 not yet triggered) combination of observed locking
496 sequences (on an arbitrary number of CPUs, running an 496 sequences (on an arbitrary number of CPUs, running an
497 arbitrary number of tasks and interrupt contexts) cause a 497 arbitrary number of tasks and interrupt contexts) cause a
498 deadlock. 498 deadlock.
499 499
500 In short, this feature enables the kernel to report locking 500 In short, this feature enables the kernel to report locking
501 related deadlocks before they actually occur. 501 related deadlocks before they actually occur.
502 502
503 The proof does not depend on how hard and complex a 503 The proof does not depend on how hard and complex a
504 deadlock scenario would be to trigger: how many 504 deadlock scenario would be to trigger: how many
505 participant CPUs, tasks and irq-contexts would be needed 505 participant CPUs, tasks and irq-contexts would be needed
506 for it to trigger. The proof also does not depend on 506 for it to trigger. The proof also does not depend on
507 timing: if a race and a resulting deadlock is possible 507 timing: if a race and a resulting deadlock is possible
508 theoretically (no matter how unlikely the race scenario 508 theoretically (no matter how unlikely the race scenario
509 is), it will be proven so and will immediately be 509 is), it will be proven so and will immediately be
510 reported by the kernel (once the event is observed that 510 reported by the kernel (once the event is observed that
511 makes the deadlock theoretically possible). 511 makes the deadlock theoretically possible).
512 512
513 If a deadlock is impossible (i.e. the locking rules, as 513 If a deadlock is impossible (i.e. the locking rules, as
514 observed by the kernel, are mathematically correct), the 514 observed by the kernel, are mathematically correct), the
515 kernel reports nothing. 515 kernel reports nothing.
516 516
517 NOTE: this feature can also be enabled for rwlocks, mutexes 517 NOTE: this feature can also be enabled for rwlocks, mutexes
518 and rwsems - in which case all dependencies between these 518 and rwsems - in which case all dependencies between these
519 different locking variants are observed and mapped too, and 519 different locking variants are observed and mapped too, and
520 the proof of observed correctness is also maintained for an 520 the proof of observed correctness is also maintained for an
521 arbitrary combination of these separate locking variants. 521 arbitrary combination of these separate locking variants.
522 522
523 For more details, see Documentation/lockdep-design.txt. 523 For more details, see Documentation/lockdep-design.txt.
524 524
525 config PROVE_RCU 525 config PROVE_RCU
526 bool "RCU debugging: prove RCU correctness" 526 bool "RCU debugging: prove RCU correctness"
527 depends on PROVE_LOCKING 527 depends on PROVE_LOCKING
528 default n 528 default n
529 help 529 help
530 This feature enables lockdep extensions that check for correct 530 This feature enables lockdep extensions that check for correct
531 use of RCU APIs. This is currently under development. Say Y 531 use of RCU APIs. This is currently under development. Say Y
532 if you want to debug RCU usage or help work on the PROVE_RCU 532 if you want to debug RCU usage or help work on the PROVE_RCU
533 feature. 533 feature.
534 534
535 Say N if you are unsure. 535 Say N if you are unsure.
536 536
537 config LOCKDEP 537 config LOCKDEP
538 bool 538 bool
539 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 539 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
540 select STACKTRACE 540 select STACKTRACE
541 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390 541 select FRAME_POINTER if !MIPS && !PPC && !ARM_UNWIND && !S390
542 select KALLSYMS 542 select KALLSYMS
543 select KALLSYMS_ALL 543 select KALLSYMS_ALL
544 544
545 config LOCK_STAT 545 config LOCK_STAT
546 bool "Lock usage statistics" 546 bool "Lock usage statistics"
547 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT 547 depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
548 select LOCKDEP 548 select LOCKDEP
549 select DEBUG_SPINLOCK 549 select DEBUG_SPINLOCK
550 select DEBUG_MUTEXES 550 select DEBUG_MUTEXES
551 select DEBUG_LOCK_ALLOC 551 select DEBUG_LOCK_ALLOC
552 default n 552 default n
553 help 553 help
554 This feature enables tracking lock contention points 554 This feature enables tracking lock contention points
555 555
556 For more details, see Documentation/lockstat.txt 556 For more details, see Documentation/lockstat.txt
557 557
558 This also enables lock events required by "perf lock", 558 This also enables lock events required by "perf lock",
559 subcommand of perf. 559 subcommand of perf.
560 If you want to use "perf lock", you also need to turn on 560 If you want to use "perf lock", you also need to turn on
561 CONFIG_EVENT_TRACING. 561 CONFIG_EVENT_TRACING.
562 562
563 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events. 563 CONFIG_LOCK_STAT defines "contended" and "acquired" lock events.
564 (CONFIG_LOCKDEP defines "acquire" and "release" events.) 564 (CONFIG_LOCKDEP defines "acquire" and "release" events.)
565 565
566 config DEBUG_LOCKDEP 566 config DEBUG_LOCKDEP
567 bool "Lock dependency engine debugging" 567 bool "Lock dependency engine debugging"
568 depends on DEBUG_KERNEL && LOCKDEP 568 depends on DEBUG_KERNEL && LOCKDEP
569 help 569 help
570 If you say Y here, the lock dependency engine will do 570 If you say Y here, the lock dependency engine will do
571 additional runtime checks to debug itself, at the price 571 additional runtime checks to debug itself, at the price
572 of more runtime overhead. 572 of more runtime overhead.
573 573
574 config TRACE_IRQFLAGS 574 config TRACE_IRQFLAGS
575 depends on DEBUG_KERNEL 575 depends on DEBUG_KERNEL
576 bool 576 bool
577 default y 577 default y
578 depends on TRACE_IRQFLAGS_SUPPORT 578 depends on TRACE_IRQFLAGS_SUPPORT
579 depends on PROVE_LOCKING 579 depends on PROVE_LOCKING
580 580
581 config DEBUG_SPINLOCK_SLEEP 581 config DEBUG_SPINLOCK_SLEEP
582 bool "Spinlock debugging: sleep-inside-spinlock checking" 582 bool "Spinlock debugging: sleep-inside-spinlock checking"
583 depends on DEBUG_KERNEL 583 depends on DEBUG_KERNEL
584 help 584 help
585 If you say Y here, various routines which may sleep will become very 585 If you say Y here, various routines which may sleep will become very
586 noisy if they are called with a spinlock held. 586 noisy if they are called with a spinlock held.
587 587
588 config DEBUG_LOCKING_API_SELFTESTS 588 config DEBUG_LOCKING_API_SELFTESTS
589 bool "Locking API boot-time self-tests" 589 bool "Locking API boot-time self-tests"
590 depends on DEBUG_KERNEL 590 depends on DEBUG_KERNEL
591 help 591 help
592 Say Y here if you want the kernel to run a short self-test during 592 Say Y here if you want the kernel to run a short self-test during
593 bootup. The self-test checks whether common types of locking bugs 593 bootup. The self-test checks whether common types of locking bugs
594 are detected by debugging mechanisms or not. (if you disable 594 are detected by debugging mechanisms or not. (if you disable
595 lock debugging then those bugs wont be detected of course.) 595 lock debugging then those bugs wont be detected of course.)
596 The following locking APIs are covered: spinlocks, rwlocks, 596 The following locking APIs are covered: spinlocks, rwlocks,
597 mutexes and rwsems. 597 mutexes and rwsems.
598 598
599 config STACKTRACE 599 config STACKTRACE
600 bool 600 bool
601 depends on STACKTRACE_SUPPORT 601 depends on STACKTRACE_SUPPORT
602 602
603 config DEBUG_KOBJECT 603 config DEBUG_KOBJECT
604 bool "kobject debugging" 604 bool "kobject debugging"
605 depends on DEBUG_KERNEL 605 depends on DEBUG_KERNEL
606 help 606 help
607 If you say Y here, some extra kobject debugging messages will be sent 607 If you say Y here, some extra kobject debugging messages will be sent
608 to the syslog. 608 to the syslog.
609 609
610 config DEBUG_HIGHMEM 610 config DEBUG_HIGHMEM
611 bool "Highmem debugging" 611 bool "Highmem debugging"
612 depends on DEBUG_KERNEL && HIGHMEM 612 depends on DEBUG_KERNEL && HIGHMEM
613 help 613 help
614 This options enables addition error checking for high memory systems. 614 This options enables addition error checking for high memory systems.
615 Disable for production systems. 615 Disable for production systems.
616 616
617 config DEBUG_BUGVERBOSE 617 config DEBUG_BUGVERBOSE
618 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED 618 bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
619 depends on BUG 619 depends on BUG
620 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \ 620 depends on ARM || AVR32 || M32R || M68K || SPARC32 || SPARC64 || \
621 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300 621 FRV || SUPERH || GENERIC_BUG || BLACKFIN || MN10300
622 default y 622 default y
623 help 623 help
624 Say Y here to make BUG() panics output the file name and line number 624 Say Y here to make BUG() panics output the file name and line number
625 of the BUG call as well as the EIP and oops trace. This aids 625 of the BUG call as well as the EIP and oops trace. This aids
626 debugging but costs about 70-100K of memory. 626 debugging but costs about 70-100K of memory.
627 627
628 config DEBUG_INFO 628 config DEBUG_INFO
629 bool "Compile the kernel with debug info" 629 bool "Compile the kernel with debug info"
630 depends on DEBUG_KERNEL 630 depends on DEBUG_KERNEL
631 help 631 help
632 If you say Y here the resulting kernel image will include 632 If you say Y here the resulting kernel image will include
633 debugging info resulting in a larger kernel image. 633 debugging info resulting in a larger kernel image.
634 This adds debug symbols to the kernel and modules (gcc -g), and 634 This adds debug symbols to the kernel and modules (gcc -g), and
635 is needed if you intend to use kernel crashdump or binary object 635 is needed if you intend to use kernel crashdump or binary object
636 tools like crash, kgdb, LKCD, gdb, etc on the kernel. 636 tools like crash, kgdb, LKCD, gdb, etc on the kernel.
637 Say Y here only if you plan to debug the kernel. 637 Say Y here only if you plan to debug the kernel.
638 638
639 If unsure, say N. 639 If unsure, say N.
640 640
641 config DEBUG_VM 641 config DEBUG_VM
642 bool "Debug VM" 642 bool "Debug VM"
643 depends on DEBUG_KERNEL 643 depends on DEBUG_KERNEL
644 help 644 help
645 Enable this to turn on extended checks in the virtual-memory system 645 Enable this to turn on extended checks in the virtual-memory system
646 that may impact performance. 646 that may impact performance.
647 647
648 If unsure, say N. 648 If unsure, say N.
649 649
650 config DEBUG_VIRTUAL 650 config DEBUG_VIRTUAL
651 bool "Debug VM translations" 651 bool "Debug VM translations"
652 depends on DEBUG_KERNEL && X86 652 depends on DEBUG_KERNEL && X86
653 help 653 help
654 Enable some costly sanity checks in virtual to page code. This can 654 Enable some costly sanity checks in virtual to page code. This can
655 catch mistakes with virt_to_page() and friends. 655 catch mistakes with virt_to_page() and friends.
656 656
657 If unsure, say N. 657 If unsure, say N.
658 658
659 config DEBUG_NOMMU_REGIONS 659 config DEBUG_NOMMU_REGIONS
660 bool "Debug the global anon/private NOMMU mapping region tree" 660 bool "Debug the global anon/private NOMMU mapping region tree"
661 depends on DEBUG_KERNEL && !MMU 661 depends on DEBUG_KERNEL && !MMU
662 help 662 help
663 This option causes the global tree of anonymous and private mapping 663 This option causes the global tree of anonymous and private mapping
664 regions to be regularly checked for invalid topology. 664 regions to be regularly checked for invalid topology.
665 665
666 config DEBUG_WRITECOUNT 666 config DEBUG_WRITECOUNT
667 bool "Debug filesystem writers count" 667 bool "Debug filesystem writers count"
668 depends on DEBUG_KERNEL 668 depends on DEBUG_KERNEL
669 help 669 help
670 Enable this to catch wrong use of the writers count in struct 670 Enable this to catch wrong use of the writers count in struct
671 vfsmount. This will increase the size of each file struct by 671 vfsmount. This will increase the size of each file struct by
672 32 bits. 672 32 bits.
673 673
674 If unsure, say N. 674 If unsure, say N.
675 675
676 config DEBUG_MEMORY_INIT 676 config DEBUG_MEMORY_INIT
677 bool "Debug memory initialisation" if EMBEDDED 677 bool "Debug memory initialisation" if EMBEDDED
678 default !EMBEDDED 678 default !EMBEDDED
679 help 679 help
680 Enable this for additional checks during memory initialisation. 680 Enable this for additional checks during memory initialisation.
681 The sanity checks verify aspects of the VM such as the memory model 681 The sanity checks verify aspects of the VM such as the memory model
682 and other information provided by the architecture. Verbose 682 and other information provided by the architecture. Verbose
683 information will be printed at KERN_DEBUG loglevel depending 683 information will be printed at KERN_DEBUG loglevel depending
684 on the mminit_loglevel= command-line option. 684 on the mminit_loglevel= command-line option.
685 685
686 If unsure, say Y 686 If unsure, say Y
687 687
688 config DEBUG_LIST 688 config DEBUG_LIST
689 bool "Debug linked list manipulation" 689 bool "Debug linked list manipulation"
690 depends on DEBUG_KERNEL 690 depends on DEBUG_KERNEL
691 help 691 help
692 Enable this to turn on extended checks in the linked-list 692 Enable this to turn on extended checks in the linked-list
693 walking routines. 693 walking routines.
694 694
695 If unsure, say N. 695 If unsure, say N.
696 696
697 config DEBUG_SG 697 config DEBUG_SG
698 bool "Debug SG table operations" 698 bool "Debug SG table operations"
699 depends on DEBUG_KERNEL 699 depends on DEBUG_KERNEL
700 help 700 help
701 Enable this to turn on checks on scatter-gather tables. This can 701 Enable this to turn on checks on scatter-gather tables. This can
702 help find problems with drivers that do not properly initialize 702 help find problems with drivers that do not properly initialize
703 their sg tables. 703 their sg tables.
704 704
705 If unsure, say N. 705 If unsure, say N.
706 706
707 config DEBUG_NOTIFIERS 707 config DEBUG_NOTIFIERS
708 bool "Debug notifier call chains" 708 bool "Debug notifier call chains"
709 depends on DEBUG_KERNEL 709 depends on DEBUG_KERNEL
710 help 710 help
711 Enable this to turn on sanity checking for notifier call chains. 711 Enable this to turn on sanity checking for notifier call chains.
712 This is most useful for kernel developers to make sure that 712 This is most useful for kernel developers to make sure that
713 modules properly unregister themselves from notifier chains. 713 modules properly unregister themselves from notifier chains.
714 This is a relatively cheap check but if you care about maximum 714 This is a relatively cheap check but if you care about maximum
715 performance, say N. 715 performance, say N.
716 716
717 config DEBUG_CREDENTIALS 717 config DEBUG_CREDENTIALS
718 bool "Debug credential management" 718 bool "Debug credential management"
719 depends on DEBUG_KERNEL 719 depends on DEBUG_KERNEL
720 help 720 help
721 Enable this to turn on some debug checking for credential 721 Enable this to turn on some debug checking for credential
722 management. The additional code keeps track of the number of 722 management. The additional code keeps track of the number of
723 pointers from task_structs to any given cred struct, and checks to 723 pointers from task_structs to any given cred struct, and checks to
724 see that this number never exceeds the usage count of the cred 724 see that this number never exceeds the usage count of the cred
725 struct. 725 struct.
726 726
727 Furthermore, if SELinux is enabled, this also checks that the 727 Furthermore, if SELinux is enabled, this also checks that the
728 security pointer in the cred struct is never seen to be invalid. 728 security pointer in the cred struct is never seen to be invalid.
729 729
730 If unsure, say N. 730 If unsure, say N.
731 731
732 # 732 #
733 # Select this config option from the architecture Kconfig, if it 733 # Select this config option from the architecture Kconfig, if it
734 # it is preferred to always offer frame pointers as a config 734 # it is preferred to always offer frame pointers as a config
735 # option on the architecture (regardless of KERNEL_DEBUG): 735 # option on the architecture (regardless of KERNEL_DEBUG):
736 # 736 #
737 config ARCH_WANT_FRAME_POINTERS 737 config ARCH_WANT_FRAME_POINTERS
738 bool 738 bool
739 help 739 help
740 740
741 config FRAME_POINTER 741 config FRAME_POINTER
742 bool "Compile the kernel with frame pointers" 742 bool "Compile the kernel with frame pointers"
743 depends on DEBUG_KERNEL && \ 743 depends on DEBUG_KERNEL && \
744 (CRIS || M68K || M68KNOMMU || FRV || UML || \ 744 (CRIS || M68K || M68KNOMMU || FRV || UML || \
745 AVR32 || SUPERH || BLACKFIN || MN10300) || \ 745 AVR32 || SUPERH || BLACKFIN || MN10300) || \
746 ARCH_WANT_FRAME_POINTERS 746 ARCH_WANT_FRAME_POINTERS
747 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS 747 default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS
748 help 748 help
749 If you say Y here the resulting kernel image will be slightly 749 If you say Y here the resulting kernel image will be slightly
750 larger and slower, but it gives very useful debugging information 750 larger and slower, but it gives very useful debugging information
751 in case of kernel bugs. (precise oopses/stacktraces/warnings) 751 in case of kernel bugs. (precise oopses/stacktraces/warnings)
752 752
753 config BOOT_PRINTK_DELAY 753 config BOOT_PRINTK_DELAY
754 bool "Delay each boot printk message by N milliseconds" 754 bool "Delay each boot printk message by N milliseconds"
755 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY 755 depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
756 help 756 help
757 This build option allows you to read kernel boot messages 757 This build option allows you to read kernel boot messages
758 by inserting a short delay after each one. The delay is 758 by inserting a short delay after each one. The delay is
759 specified in milliseconds on the kernel command line, 759 specified in milliseconds on the kernel command line,
760 using "boot_delay=N". 760 using "boot_delay=N".
761 761
762 It is likely that you would also need to use "lpj=M" to preset 762 It is likely that you would also need to use "lpj=M" to preset
763 the "loops per jiffie" value. 763 the "loops per jiffie" value.
764 See a previous boot log for the "lpj" value to use for your 764 See a previous boot log for the "lpj" value to use for your
765 system, and then set "lpj=M" before setting "boot_delay=N". 765 system, and then set "lpj=M" before setting "boot_delay=N".
766 NOTE: Using this option may adversely affect SMP systems. 766 NOTE: Using this option may adversely affect SMP systems.
767 I.e., processors other than the first one may not boot up. 767 I.e., processors other than the first one may not boot up.
768 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect 768 BOOT_PRINTK_DELAY also may cause DETECT_SOFTLOCKUP to detect
769 what it believes to be lockup conditions. 769 what it believes to be lockup conditions.
770 770
771 config RCU_TORTURE_TEST 771 config RCU_TORTURE_TEST
772 tristate "torture tests for RCU" 772 tristate "torture tests for RCU"
773 depends on DEBUG_KERNEL 773 depends on DEBUG_KERNEL
774 default n 774 default n
775 help 775 help
776 This option provides a kernel module that runs torture tests 776 This option provides a kernel module that runs torture tests
777 on the RCU infrastructure. The kernel module may be built 777 on the RCU infrastructure. The kernel module may be built
778 after the fact on the running kernel to be tested, if desired. 778 after the fact on the running kernel to be tested, if desired.
779 779
780 Say Y here if you want RCU torture tests to be built into 780 Say Y here if you want RCU torture tests to be built into
781 the kernel. 781 the kernel.
782 Say M if you want the RCU torture tests to build as a module. 782 Say M if you want the RCU torture tests to build as a module.
783 Say N if you are unsure. 783 Say N if you are unsure.
784 784
785 config RCU_TORTURE_TEST_RUNNABLE 785 config RCU_TORTURE_TEST_RUNNABLE
786 bool "torture tests for RCU runnable by default" 786 bool "torture tests for RCU runnable by default"
787 depends on RCU_TORTURE_TEST = y 787 depends on RCU_TORTURE_TEST = y
788 default n 788 default n
789 help 789 help
790 This option provides a way to build the RCU torture tests 790 This option provides a way to build the RCU torture tests
791 directly into the kernel without them starting up at boot 791 directly into the kernel without them starting up at boot
792 time. You can use /proc/sys/kernel/rcutorture_runnable 792 time. You can use /proc/sys/kernel/rcutorture_runnable
793 to manually override this setting. This /proc file is 793 to manually override this setting. This /proc file is
794 available only when the RCU torture tests have been built 794 available only when the RCU torture tests have been built
795 into the kernel. 795 into the kernel.
796 796
797 Say Y here if you want the RCU torture tests to start during 797 Say Y here if you want the RCU torture tests to start during
798 boot (you probably don't). 798 boot (you probably don't).
799 Say N here if you want the RCU torture tests to start only 799 Say N here if you want the RCU torture tests to start only
800 after being manually enabled via /proc. 800 after being manually enabled via /proc.
801 801
802 config RCU_CPU_STALL_DETECTOR 802 config RCU_CPU_STALL_DETECTOR
803 bool "Check for stalled CPUs delaying RCU grace periods" 803 bool "Check for stalled CPUs delaying RCU grace periods"
804 depends on TREE_RCU || TREE_PREEMPT_RCU 804 depends on TREE_RCU || TREE_PREEMPT_RCU
805 default y 805 default y
806 help 806 help
807 This option causes RCU to printk information on which 807 This option causes RCU to printk information on which
808 CPUs are delaying the current grace period, but only when 808 CPUs are delaying the current grace period, but only when
809 the grace period extends for excessive time periods. 809 the grace period extends for excessive time periods.
810 810
811 Say N if you want to disable such checks. 811 Say N if you want to disable such checks.
812 812
813 Say Y if you are unsure. 813 Say Y if you are unsure.
814 814
815 config RCU_CPU_STALL_VERBOSE 815 config RCU_CPU_STALL_VERBOSE
816 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR" 816 bool "Print additional per-task information for RCU_CPU_STALL_DETECTOR"
817 depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU 817 depends on RCU_CPU_STALL_DETECTOR && TREE_PREEMPT_RCU
818 default n 818 default n
819 help 819 help
820 This option causes RCU to printk detailed per-task information 820 This option causes RCU to printk detailed per-task information
821 for any tasks that are stalling the current RCU grace period. 821 for any tasks that are stalling the current RCU grace period.
822 822
823 Say N if you are unsure. 823 Say N if you are unsure.
824 824
825 Say Y if you want to enable such checks. 825 Say Y if you want to enable such checks.
826 826
827 config KPROBES_SANITY_TEST 827 config KPROBES_SANITY_TEST
828 bool "Kprobes sanity tests" 828 bool "Kprobes sanity tests"
829 depends on DEBUG_KERNEL 829 depends on DEBUG_KERNEL
830 depends on KPROBES 830 depends on KPROBES
831 default n 831 default n
832 help 832 help
833 This option provides for testing basic kprobes functionality on 833 This option provides for testing basic kprobes functionality on
834 boot. A sample kprobe, jprobe and kretprobe are inserted and 834 boot. A sample kprobe, jprobe and kretprobe are inserted and
835 verified for functionality. 835 verified for functionality.
836 836
837 Say N if you are unsure. 837 Say N if you are unsure.
838 838
839 config BACKTRACE_SELF_TEST 839 config BACKTRACE_SELF_TEST
840 tristate "Self test for the backtrace code" 840 tristate "Self test for the backtrace code"
841 depends on DEBUG_KERNEL 841 depends on DEBUG_KERNEL
842 default n 842 default n
843 help 843 help
844 This option provides a kernel module that can be used to test 844 This option provides a kernel module that can be used to test
845 the kernel stack backtrace code. This option is not useful 845 the kernel stack backtrace code. This option is not useful
846 for distributions or general kernels, but only for kernel 846 for distributions or general kernels, but only for kernel
847 developers working on architecture code. 847 developers working on architecture code.
848 848
849 Note that if you want to also test saved backtraces, you will 849 Note that if you want to also test saved backtraces, you will
850 have to enable STACKTRACE as well. 850 have to enable STACKTRACE as well.
851 851
852 Say N if you are unsure. 852 Say N if you are unsure.
853 853
854 config DEBUG_BLOCK_EXT_DEVT 854 config DEBUG_BLOCK_EXT_DEVT
855 bool "Force extended block device numbers and spread them" 855 bool "Force extended block device numbers and spread them"
856 depends on DEBUG_KERNEL 856 depends on DEBUG_KERNEL
857 depends on BLOCK 857 depends on BLOCK
858 default n 858 default n
859 help 859 help
860 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON 860 BIG FAT WARNING: ENABLING THIS OPTION MIGHT BREAK BOOTING ON
861 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT 861 SOME DISTRIBUTIONS. DO NOT ENABLE THIS UNLESS YOU KNOW WHAT
862 YOU ARE DOING. Distros, please enable this and fix whatever 862 YOU ARE DOING. Distros, please enable this and fix whatever
863 is broken. 863 is broken.
864 864
865 Conventionally, block device numbers are allocated from 865 Conventionally, block device numbers are allocated from
866 predetermined contiguous area. However, extended block area 866 predetermined contiguous area. However, extended block area
867 may introduce non-contiguous block device numbers. This 867 may introduce non-contiguous block device numbers. This
868 option forces most block device numbers to be allocated from 868 option forces most block device numbers to be allocated from
869 the extended space and spreads them to discover kernel or 869 the extended space and spreads them to discover kernel or
870 userland code paths which assume predetermined contiguous 870 userland code paths which assume predetermined contiguous
871 device number allocation. 871 device number allocation.
872 872
873 Note that turning on this debug option shuffles all the 873 Note that turning on this debug option shuffles all the
874 device numbers for all IDE and SCSI devices including libata 874 device numbers for all IDE and SCSI devices including libata
875 ones, so root partition specified using device number 875 ones, so root partition specified using device number
876 directly (via rdev or root=MAJ:MIN) won't work anymore. 876 directly (via rdev or root=MAJ:MIN) won't work anymore.
877 Textual device names (root=/dev/sdXn) will continue to work. 877 Textual device names (root=/dev/sdXn) will continue to work.
878 878
879 Say N if you are unsure. 879 Say N if you are unsure.
880 880
881 config DEBUG_FORCE_WEAK_PER_CPU 881 config DEBUG_FORCE_WEAK_PER_CPU
882 bool "Force weak per-cpu definitions" 882 bool "Force weak per-cpu definitions"
883 depends on DEBUG_KERNEL 883 depends on DEBUG_KERNEL
884 help 884 help
885 s390 and alpha require percpu variables in modules to be 885 s390 and alpha require percpu variables in modules to be
886 defined weak to work around addressing range issue which 886 defined weak to work around addressing range issue which
887 puts the following two restrictions on percpu variable 887 puts the following two restrictions on percpu variable
888 definitions. 888 definitions.
889 889
890 1. percpu symbols must be unique whether static or not 890 1. percpu symbols must be unique whether static or not
891 2. percpu variables can't be defined inside a function 891 2. percpu variables can't be defined inside a function
892 892
893 To ensure that generic code follows the above rules, this 893 To ensure that generic code follows the above rules, this
894 option forces all percpu variables to be defined as weak. 894 option forces all percpu variables to be defined as weak.
895 895
896 config LKDTM 896 config LKDTM
897 tristate "Linux Kernel Dump Test Tool Module" 897 tristate "Linux Kernel Dump Test Tool Module"
898 depends on DEBUG_FS 898 depends on DEBUG_FS
899 depends on BLOCK 899 depends on BLOCK
900 default n 900 default n
901 help 901 help
902 This module enables testing of the different dumping mechanisms by 902 This module enables testing of the different dumping mechanisms by
903 inducing system failures at predefined crash points. 903 inducing system failures at predefined crash points.
904 If you don't need it: say N 904 If you don't need it: say N
905 Choose M here to compile this code as a module. The module will be 905 Choose M here to compile this code as a module. The module will be
906 called lkdtm. 906 called lkdtm.
907 907
908 Documentation on how to use the module can be found in 908 Documentation on how to use the module can be found in
909 Documentation/fault-injection/provoke-crashes.txt 909 Documentation/fault-injection/provoke-crashes.txt
910 910
911 config FAULT_INJECTION 911 config FAULT_INJECTION
912 bool "Fault-injection framework" 912 bool "Fault-injection framework"
913 depends on DEBUG_KERNEL 913 depends on DEBUG_KERNEL
914 help 914 help
915 Provide fault-injection framework. 915 Provide fault-injection framework.
916 For more details, see Documentation/fault-injection/. 916 For more details, see Documentation/fault-injection/.
917 917
918 config FAILSLAB 918 config FAILSLAB
919 bool "Fault-injection capability for kmalloc" 919 bool "Fault-injection capability for kmalloc"
920 depends on FAULT_INJECTION 920 depends on FAULT_INJECTION
921 depends on SLAB || SLUB 921 depends on SLAB || SLUB
922 help 922 help
923 Provide fault-injection capability for kmalloc. 923 Provide fault-injection capability for kmalloc.
924 924
925 config FAIL_PAGE_ALLOC 925 config FAIL_PAGE_ALLOC
926 bool "Fault-injection capabilitiy for alloc_pages()" 926 bool "Fault-injection capabilitiy for alloc_pages()"
927 depends on FAULT_INJECTION 927 depends on FAULT_INJECTION
928 help 928 help
929 Provide fault-injection capability for alloc_pages(). 929 Provide fault-injection capability for alloc_pages().
930 930
931 config FAIL_MAKE_REQUEST 931 config FAIL_MAKE_REQUEST
932 bool "Fault-injection capability for disk IO" 932 bool "Fault-injection capability for disk IO"
933 depends on FAULT_INJECTION && BLOCK 933 depends on FAULT_INJECTION && BLOCK
934 help 934 help
935 Provide fault-injection capability for disk IO. 935 Provide fault-injection capability for disk IO.
936 936
937 config FAIL_IO_TIMEOUT 937 config FAIL_IO_TIMEOUT
938 bool "Faul-injection capability for faking disk interrupts" 938 bool "Faul-injection capability for faking disk interrupts"
939 depends on FAULT_INJECTION && BLOCK 939 depends on FAULT_INJECTION && BLOCK
940 help 940 help
941 Provide fault-injection capability on end IO handling. This 941 Provide fault-injection capability on end IO handling. This
942 will make the block layer "forget" an interrupt as configured, 942 will make the block layer "forget" an interrupt as configured,
943 thus exercising the error handling. 943 thus exercising the error handling.
944 944
945 Only works with drivers that use the generic timeout handling, 945 Only works with drivers that use the generic timeout handling,
946 for others it wont do anything. 946 for others it wont do anything.
947 947
948 config FAULT_INJECTION_DEBUG_FS 948 config FAULT_INJECTION_DEBUG_FS
949 bool "Debugfs entries for fault-injection capabilities" 949 bool "Debugfs entries for fault-injection capabilities"
950 depends on FAULT_INJECTION && SYSFS && DEBUG_FS 950 depends on FAULT_INJECTION && SYSFS && DEBUG_FS
951 help 951 help
952 Enable configuration of fault-injection capabilities via debugfs. 952 Enable configuration of fault-injection capabilities via debugfs.
953 953
954 config FAULT_INJECTION_STACKTRACE_FILTER 954 config FAULT_INJECTION_STACKTRACE_FILTER
955 bool "stacktrace filter for fault-injection capabilities" 955 bool "stacktrace filter for fault-injection capabilities"
956 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT 956 depends on FAULT_INJECTION_DEBUG_FS && STACKTRACE_SUPPORT
957 depends on !X86_64 957 depends on !X86_64
958 select STACKTRACE 958 select STACKTRACE
959 select FRAME_POINTER if !PPC && !S390 959 select FRAME_POINTER if !PPC && !S390
960 help 960 help
961 Provide stacktrace filter for fault-injection capabilities 961 Provide stacktrace filter for fault-injection capabilities
962 962
963 config LATENCYTOP 963 config LATENCYTOP
964 bool "Latency measuring infrastructure" 964 bool "Latency measuring infrastructure"
965 select FRAME_POINTER if !MIPS && !PPC && !S390 965 select FRAME_POINTER if !MIPS && !PPC && !S390
966 select KALLSYMS 966 select KALLSYMS
967 select KALLSYMS_ALL 967 select KALLSYMS_ALL
968 select STACKTRACE 968 select STACKTRACE
969 select SCHEDSTATS 969 select SCHEDSTATS
970 select SCHED_DEBUG 970 select SCHED_DEBUG
971 depends on HAVE_LATENCYTOP_SUPPORT 971 depends on HAVE_LATENCYTOP_SUPPORT
972 help 972 help
973 Enable this option if you want to use the LatencyTOP tool 973 Enable this option if you want to use the LatencyTOP tool
974 to find out which userspace is blocking on what kernel operations. 974 to find out which userspace is blocking on what kernel operations.
975 975
976 config SYSCTL_SYSCALL_CHECK 976 config SYSCTL_SYSCALL_CHECK
977 bool "Sysctl checks" 977 bool "Sysctl checks"
978 depends on SYSCTL 978 depends on SYSCTL
979 ---help--- 979 ---help---
980 sys_sysctl uses binary paths that have been found challenging 980 sys_sysctl uses binary paths that have been found challenging
981 to properly maintain and use. This enables checks that help 981 to properly maintain and use. This enables checks that help
982 you to keep things correct. 982 you to keep things correct.
983 983
984 source mm/Kconfig.debug 984 source mm/Kconfig.debug
985 source kernel/trace/Kconfig 985 source kernel/trace/Kconfig
986 986
987 config PROVIDE_OHCI1394_DMA_INIT 987 config PROVIDE_OHCI1394_DMA_INIT
988 bool "Remote debugging over FireWire early on boot" 988 bool "Remote debugging over FireWire early on boot"
989 depends on PCI && X86 989 depends on PCI && X86
990 help 990 help
991 If you want to debug problems which hang or crash the kernel early 991 If you want to debug problems which hang or crash the kernel early
992 on boot and the crashing machine has a FireWire port, you can use 992 on boot and the crashing machine has a FireWire port, you can use
993 this feature to remotely access the memory of the crashed machine 993 this feature to remotely access the memory of the crashed machine
994 over FireWire. This employs remote DMA as part of the OHCI1394 994 over FireWire. This employs remote DMA as part of the OHCI1394
995 specification which is now the standard for FireWire controllers. 995 specification which is now the standard for FireWire controllers.
996 996
997 With remote DMA, you can monitor the printk buffer remotely using 997 With remote DMA, you can monitor the printk buffer remotely using
998 firescope and access all memory below 4GB using fireproxy from gdb. 998 firescope and access all memory below 4GB using fireproxy from gdb.
999 Even controlling a kernel debugger is possible using remote DMA. 999 Even controlling a kernel debugger is possible using remote DMA.
1000 1000
1001 Usage: 1001 Usage:
1002 1002
1003 If ohci1394_dma=early is used as boot parameter, it will initialize 1003 If ohci1394_dma=early is used as boot parameter, it will initialize
1004 all OHCI1394 controllers which are found in the PCI config space. 1004 all OHCI1394 controllers which are found in the PCI config space.
1005 1005
1006 As all changes to the FireWire bus such as enabling and disabling 1006 As all changes to the FireWire bus such as enabling and disabling
1007 devices cause a bus reset and thereby disable remote DMA for all 1007 devices cause a bus reset and thereby disable remote DMA for all
1008 devices, be sure to have the cable plugged and FireWire enabled on 1008 devices, be sure to have the cable plugged and FireWire enabled on
1009 the debugging host before booting the debug target for debugging. 1009 the debugging host before booting the debug target for debugging.
1010 1010
1011 This code (~1k) is freed after boot. By then, the firewire stack 1011 This code (~1k) is freed after boot. By then, the firewire stack
1012 in charge of the OHCI-1394 controllers should be used instead. 1012 in charge of the OHCI-1394 controllers should be used instead.
1013 1013
1014 See Documentation/debugging-via-ohci1394.txt for more information. 1014 See Documentation/debugging-via-ohci1394.txt for more information.
1015 1015
1016 config FIREWIRE_OHCI_REMOTE_DMA 1016 config FIREWIRE_OHCI_REMOTE_DMA
1017 bool "Remote debugging over FireWire with firewire-ohci" 1017 bool "Remote debugging over FireWire with firewire-ohci"
1018 depends on FIREWIRE_OHCI 1018 depends on FIREWIRE_OHCI
1019 help 1019 help
1020 This option lets you use the FireWire bus for remote debugging 1020 This option lets you use the FireWire bus for remote debugging
1021 with help of the firewire-ohci driver. It enables unfiltered 1021 with help of the firewire-ohci driver. It enables unfiltered
1022 remote DMA in firewire-ohci. 1022 remote DMA in firewire-ohci.
1023 See Documentation/debugging-via-ohci1394.txt for more information. 1023 See Documentation/debugging-via-ohci1394.txt for more information.
1024 1024
1025 If unsure, say N. 1025 If unsure, say N.
1026 1026
1027 config BUILD_DOCSRC 1027 config BUILD_DOCSRC
1028 bool "Build targets in Documentation/ tree" 1028 bool "Build targets in Documentation/ tree"
1029 depends on HEADERS_CHECK 1029 depends on HEADERS_CHECK
1030 help 1030 help
1031 This option attempts to build objects from the source files in the 1031 This option attempts to build objects from the source files in the
1032 kernel Documentation/ tree. 1032 kernel Documentation/ tree.
1033 1033
1034 Say N if you are unsure. 1034 Say N if you are unsure.
1035 1035
1036 config DYNAMIC_DEBUG 1036 config DYNAMIC_DEBUG
1037 bool "Enable dynamic printk() support" 1037 bool "Enable dynamic printk() support"
1038 default n 1038 default n
1039 depends on PRINTK 1039 depends on PRINTK
1040 depends on DEBUG_FS 1040 depends on DEBUG_FS
1041 help 1041 help
1042 1042
1043 Compiles debug level messages into the kernel, which would not 1043 Compiles debug level messages into the kernel, which would not
1044 otherwise be available at runtime. These messages can then be 1044 otherwise be available at runtime. These messages can then be
1045 enabled/disabled based on various levels of scope - per source file, 1045 enabled/disabled based on various levels of scope - per source file,
1046 function, module, format string, and line number. This mechanism 1046 function, module, format string, and line number. This mechanism
1047 implicitly enables all pr_debug() and dev_dbg() calls. The impact of 1047 implicitly enables all pr_debug() and dev_dbg() calls. The impact of
1048 this compile option is a larger kernel text size of about 2%. 1048 this compile option is a larger kernel text size of about 2%.
1049 1049
1050 Usage: 1050 Usage:
1051 1051
1052 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file, 1052 Dynamic debugging is controlled via the 'dynamic_debug/ddebug' file,
1053 which is contained in the 'debugfs' filesystem. Thus, the debugfs 1053 which is contained in the 'debugfs' filesystem. Thus, the debugfs
1054 filesystem must first be mounted before making use of this feature. 1054 filesystem must first be mounted before making use of this feature.
1055 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This 1055 We refer the control file as: <debugfs>/dynamic_debug/ddebug. This
1056 file contains a list of the debug statements that can be enabled. The 1056 file contains a list of the debug statements that can be enabled. The
1057 format for each line of the file is: 1057 format for each line of the file is:
1058 1058
1059 filename:lineno [module]function flags format 1059 filename:lineno [module]function flags format
1060 1060
1061 filename : source file of the debug statement 1061 filename : source file of the debug statement
1062 lineno : line number of the debug statement 1062 lineno : line number of the debug statement
1063 module : module that contains the debug statement 1063 module : module that contains the debug statement
1064 function : function that contains the debug statement 1064 function : function that contains the debug statement
1065 flags : 'p' means the line is turned 'on' for printing 1065 flags : 'p' means the line is turned 'on' for printing
1066 format : the format used for the debug statement 1066 format : the format used for the debug statement
1067 1067
1068 From a live system: 1068 From a live system:
1069 1069
1070 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug 1070 nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
1071 # filename:lineno [module]function flags format 1071 # filename:lineno [module]function flags format
1072 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012" 1072 fs/aio.c:222 [aio]__put_ioctx - "__put_ioctx:\040freeing\040%p\012"
1073 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012" 1073 fs/aio.c:248 [aio]ioctx_alloc - "ENOMEM:\040nr_events\040too\040high\012"
1074 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012" 1074 fs/aio.c:1770 [aio]sys_io_cancel - "calling\040cancel\012"
1075 1075
1076 Example usage: 1076 Example usage:
1077 1077
1078 // enable the message at line 1603 of file svcsock.c 1078 // enable the message at line 1603 of file svcsock.c
1079 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' > 1079 nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
1080 <debugfs>/dynamic_debug/ddebug 1080 <debugfs>/dynamic_debug/ddebug
1081 1081
1082 // enable all the messages in file svcsock.c 1082 // enable all the messages in file svcsock.c
1083 nullarbor:~ # echo -n 'file svcsock.c +p' > 1083 nullarbor:~ # echo -n 'file svcsock.c +p' >
1084 <debugfs>/dynamic_debug/ddebug 1084 <debugfs>/dynamic_debug/ddebug
1085 1085
1086 // enable all the messages in the NFS server module 1086 // enable all the messages in the NFS server module
1087 nullarbor:~ # echo -n 'module nfsd +p' > 1087 nullarbor:~ # echo -n 'module nfsd +p' >
1088 <debugfs>/dynamic_debug/ddebug 1088 <debugfs>/dynamic_debug/ddebug
1089 1089
1090 // enable all 12 messages in the function svc_process() 1090 // enable all 12 messages in the function svc_process()
1091 nullarbor:~ # echo -n 'func svc_process +p' > 1091 nullarbor:~ # echo -n 'func svc_process +p' >
1092 <debugfs>/dynamic_debug/ddebug 1092 <debugfs>/dynamic_debug/ddebug
1093 1093
1094 // disable all 12 messages in the function svc_process() 1094 // disable all 12 messages in the function svc_process()
1095 nullarbor:~ # echo -n 'func svc_process -p' > 1095 nullarbor:~ # echo -n 'func svc_process -p' >
1096 <debugfs>/dynamic_debug/ddebug 1096 <debugfs>/dynamic_debug/ddebug
1097 1097
1098 See Documentation/dynamic-debug-howto.txt for additional information. 1098 See Documentation/dynamic-debug-howto.txt for additional information.
1099 1099
1100 config DMA_API_DEBUG 1100 config DMA_API_DEBUG
1101 bool "Enable debugging of DMA-API usage" 1101 bool "Enable debugging of DMA-API usage"
1102 depends on HAVE_DMA_API_DEBUG 1102 depends on HAVE_DMA_API_DEBUG
1103 help 1103 help
1104 Enable this option to debug the use of the DMA API by device drivers. 1104 Enable this option to debug the use of the DMA API by device drivers.
1105 With this option you will be able to detect common bugs in device 1105 With this option you will be able to detect common bugs in device
1106 drivers like double-freeing of DMA mappings or freeing mappings that 1106 drivers like double-freeing of DMA mappings or freeing mappings that
1107 were never allocated. 1107 were never allocated.
1108 This option causes a performance degredation. Use only if you want 1108 This option causes a performance degredation. Use only if you want
1109 to debug device drivers. If unsure, say N. 1109 to debug device drivers. If unsure, say N.
1110 1110
1111 source "samples/Kconfig" 1111 source "samples/Kconfig"
1112 1112
1113 source "lib/Kconfig.kgdb" 1113 source "lib/Kconfig.kgdb"
1114 1114
1115 source "lib/Kconfig.kmemcheck" 1115 source "lib/Kconfig.kmemcheck"
1116 1116