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Commit c99c30feadf664ccd8590b96259cb9f3954bd246

Authored by Ingo Molnar
1 parent 47195d5763
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

nmi_watchdog: Turn it off by default 

It was nice to enable it by default for testing - but before we
push it upstream we want it to be off - so that people can
opt-in gradually.

Cc: Don Zickus <dzickus@redhat.com>
Cc: peterz@infradead.org
Cc: gorcunov@gmail.com
Cc: aris@redhat.com
LKML-Reference: <1266880143-24943-1-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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