[thirdparty/kernel/linux.git] / lib / Kconfig.debug


config PRINTK_TIME
	bool "Show timing information on printks"
	help
	  Selecting this option causes timing information to be
	  included in printk output.  This allows you to measure
	  the interval between kernel operations, including bootup
	  operations.  This is useful for identifying long delays
	  in kernel startup.


config MAGIC_SYSRQ
	bool "Magic SysRq key"
	depends on !UML
	help
	  If you say Y here, you will have some control over the system even
	  if the system crashes for example during kernel debugging (e.g., you
	  will be able to flush the buffer cache to disk, reboot the system
	  immediately or dump some status information). This is accomplished
	  by pressing various keys while holding SysRq (Alt+PrintScreen). It
	  also works on a serial console (on PC hardware at least), if you
	  send a BREAK and then within 5 seconds a command keypress. The
	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
	  unless you really know what this hack does.

config DEBUG_KERNEL
	bool "Kernel debugging"
	help
	  Say Y here if you are developing drivers or trying to debug and
	  identify kernel problems.

config LOG_BUF_SHIFT
	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
	range 12 21
	default 17 if S390
	default 16 if X86_NUMAQ || IA64
	default 15 if SMP
	default 14
	help
	  Select kernel log buffer size as a power of 2.
	  Defaults and Examples:
	  	     17 => 128 KB for S/390
		     16 => 64 KB for x86 NUMAQ or IA-64
	             15 => 32 KB for SMP
	             14 => 16 KB for uniprocessor
		     13 =>  8 KB
		     12 =>  4 KB

config DETECT_SOFTLOCKUP
	bool "Detect Soft Lockups"
	depends on DEBUG_KERNEL
	default y
	help
	  Say Y here to enable the kernel to detect "soft lockups",
	  which are bugs that cause the kernel to loop in kernel
	  mode for more than 10 seconds, without giving other tasks a
	  chance to run.

	  When a soft-lockup is detected, the kernel will print the
	  current stack trace (which you should report), but the
	  system will stay locked up. This feature has negligible
	  overhead.

	  (Note that "hard lockups" are separate type of bugs that
	   can be detected via the NMI-watchdog, on platforms that
	   support it.)

config SCHEDSTATS
	bool "Collect scheduler statistics"
	depends on DEBUG_KERNEL && PROC_FS
	help
	  If you say Y here, additional code will be inserted into the
	  scheduler and related routines to collect statistics about
	  scheduler behavior and provide them in /proc/schedstat.  These
	  stats may be useful for both tuning and debugging the scheduler
	  If you aren't debugging the scheduler or trying to tune a specific
	  application, you can say N to avoid the very slight overhead
	  this adds.

config DEBUG_SLAB
	bool "Debug slab memory allocations"
	depends on DEBUG_KERNEL && SLAB
	help
	  Say Y here to have the kernel do limited verification on memory
	  allocation as well as poisoning memory on free to catch use of freed
	  memory. This can make kmalloc/kfree-intensive workloads much slower.

config DEBUG_SLAB_LEAK
	bool "Memory leak debugging"
	depends on DEBUG_SLAB

config DEBUG_PREEMPT
	bool "Debug preemptible kernel"
	depends on DEBUG_KERNEL && PREEMPT
	default y
	help
	  If you say Y here then the kernel will use a debug variant of the
	  commonly used smp_processor_id() function and will print warnings
	  if kernel code uses it in a preemption-unsafe way. Also, the kernel
	  will detect preemption count underflows.

config DEBUG_MUTEXES
	bool "Mutex debugging, deadlock detection"
	default n
	depends on DEBUG_KERNEL
	help
	 This allows mutex semantics violations and mutex related deadlocks
	 (lockups) to be detected and reported automatically.

config DEBUG_RT_MUTEXES
	bool "RT Mutex debugging, deadlock detection"
	default y
	depends on DEBUG_KERNEL && RT_MUTEXES
	help
	 This allows rt mutex semantics violations and rt mutex related
	 deadlocks (lockups) to be detected and reported automatically.

config DEBUG_PI_LIST
	bool
	default y
	depends on DEBUG_RT_MUTEXES

config RT_MUTEX_TESTER
	bool "Built-in scriptable tester for rt-mutexes"
	depends on RT_MUTEXES
	default n
	help
	  This option enables a rt-mutex tester.

config DEBUG_SPINLOCK
	bool "Spinlock debugging"
	depends on DEBUG_KERNEL
	help
	  Say Y here and build SMP to catch missing spinlock initialization
	  and certain other kinds of spinlock errors commonly made.  This is
	  best used in conjunction with the NMI watchdog so that spinlock
	  deadlocks are also debuggable.

config DEBUG_SPINLOCK_SLEEP
	bool "Sleep-inside-spinlock checking"
	depends on DEBUG_KERNEL
	help
	  If you say Y here, various routines which may sleep will become very
	  noisy if they are called with a spinlock held.

config DEBUG_KOBJECT
	bool "kobject debugging"
	depends on DEBUG_KERNEL
	help
	  If you say Y here, some extra kobject debugging messages will be sent
	  to the syslog. 

config DEBUG_HIGHMEM
	bool "Highmem debugging"
	depends on DEBUG_KERNEL && HIGHMEM
	help
	  This options enables addition error checking for high memory systems.
	  Disable for production systems.

config DEBUG_BUGVERBOSE
	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
	depends on BUG
	depends on ARM || ARM26 || M32R || M68K || SPARC32 || SPARC64 || X86_32 || FRV
	default !EMBEDDED
	help
	  Say Y here to make BUG() panics output the file name and line number
	  of the BUG call as well as the EIP and oops trace.  This aids
	  debugging but costs about 70-100K of memory.

config DEBUG_INFO
	bool "Compile the kernel with debug info"
	depends on DEBUG_KERNEL
	help
          If you say Y here the resulting kernel image will include
	  debugging info resulting in a larger kernel image.
	  Say Y here only if you plan to debug the kernel.

	  If unsure, say N.

config DEBUG_FS
	bool "Debug Filesystem"
	depends on SYSFS
	help
	  debugfs is a virtual file system that kernel developers use to put
	  debugging files into.  Enable this option to be able to read and
	  write to these files.

	  If unsure, say N.

config DEBUG_VM
	bool "Debug VM"
	depends on DEBUG_KERNEL
	help
	  Enable this to turn on extended checks in the virtual-memory system
          that may impact performance.

	  If unsure, say N.

config FRAME_POINTER
	bool "Compile the kernel with frame pointers"
	depends on DEBUG_KERNEL && (X86 || CRIS || M68K || M68KNOMMU || FRV || UML)
	default y if DEBUG_INFO && UML
	help
	  If you say Y here the resulting kernel image will be slightly larger
	  and slower, but it might give very useful debugging information on
	  some architectures or if you use external debuggers.
	  If you don't debug the kernel, you can say N.

config UNWIND_INFO
	bool "Compile the kernel with frame unwind information"
	depends on !IA64 && !PARISC
	depends on !MODULES || !(MIPS || PPC || SUPERH || V850)
	help
	  If you say Y here the resulting kernel image will be slightly larger
	  but not slower, and it will give very useful debugging information.
	  If you don't debug the kernel, you can say N, but we may not be able
	  to solve problems without frame unwind information or frame pointers.

config STACK_UNWIND
	bool "Stack unwind support"
	depends on UNWIND_INFO
	depends on X86
	help
	  This enables more precise stack traces, omitting all unrelated
	  occurrences of pointers into kernel code from the dump.

config FORCED_INLINING
	bool "Force gcc to inline functions marked 'inline'"
	depends on DEBUG_KERNEL
	default y
	help
	  This option determines if the kernel forces gcc to inline the functions
	  developers have marked 'inline'. Doing so takes away freedom from gcc to
	  do what it thinks is best, which is desirable for the gcc 3.x series of
	  compilers. The gcc 4.x series have a rewritten inlining algorithm and
	  disabling this option will generate a smaller kernel there. Hopefully
	  this algorithm is so good that allowing gcc4 to make the decision can
	  become the default in the future, until then this option is there to
	  test gcc for this.

config RCU_TORTURE_TEST
	tristate "torture tests for RCU"
	depends on DEBUG_KERNEL
	default n
	help
	  This option provides a kernel module that runs torture tests
	  on the RCU infrastructure.  The kernel module may be built
	  after the fact on the running kernel to be tested, if desired.

	  Say Y here if you want RCU torture tests to start automatically
	  at boot time (you probably don't).
	  Say M if you want the RCU torture tests to build as a module.
	  Say N if you are unsure.
Commit	Line	Data
1da177e4 LT	1
	2	config PRINTK_TIME
	3	bool "Show timing information on printks"
	4	help
	5	Selecting this option causes timing information to be
	6	included in printk output. This allows you to measure
	7	the interval between kernel operations, including bootup
	8	operations. This is useful for identifying long delays
	9	in kernel startup.
	10
	11
1da177e4 LT	12	config MAGIC_SYSRQ
1da177e4 LT	13	bool "Magic SysRq key"
f346f4b3	14	depends on !UML
1da177e4 LT	15	help
	16	If you say Y here, you will have some control over the system even
	17	if the system crashes for example during kernel debugging (e.g., you
	18	will be able to flush the buffer cache to disk, reboot the system
	19	immediately or dump some status information). This is accomplished
	20	by pressing various keys while holding SysRq (Alt+PrintScreen). It
	21	also works on a serial console (on PC hardware at least), if you
	22	send a BREAK and then within 5 seconds a command keypress. The
	23	keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
	24	unless you really know what this hack does.
	25
f346f4b3 AB	26	config DEBUG_KERNEL
	27	bool "Kernel debugging"
	28	help
	29	Say Y here if you are developing drivers or trying to debug and
	30	identify kernel problems.
	31
1da177e4 LT	32	config LOG_BUF_SHIFT
	33	int "Kernel log buffer size (16 => 64KB, 17 => 128KB)" if DEBUG_KERNEL
	34	range 12 21
347a8dc3	35	default 17 if S390
1da177e4 LT	36	default 16 if X86_NUMAQ \|\| IA64
	37	default 15 if SMP
	38	default 14
	39	help
	40	Select kernel log buffer size as a power of 2.
	41	Defaults and Examples:
	42	17 => 128 KB for S/390
	43	16 => 64 KB for x86 NUMAQ or IA-64
	44	15 => 32 KB for SMP
	45	14 => 16 KB for uniprocessor
	46	13 => 8 KB
	47	12 => 4 KB
	48
8446f1d3 IM	49	config DETECT_SOFTLOCKUP
	50	bool "Detect Soft Lockups"
	51	depends on DEBUG_KERNEL
	52	default y
	53	help
	54	Say Y here to enable the kernel to detect "soft lockups",
	55	which are bugs that cause the kernel to loop in kernel
	56	mode for more than 10 seconds, without giving other tasks a
	57	chance to run.
	58
	59	When a soft-lockup is detected, the kernel will print the
	60	current stack trace (which you should report), but the
	61	system will stay locked up. This feature has negligible
	62	overhead.
	63
	64	(Note that "hard lockups" are separate type of bugs that
	65	can be detected via the NMI-watchdog, on platforms that
	66	support it.)
	67
1da177e4 LT	68	config SCHEDSTATS
	69	bool "Collect scheduler statistics"
	70	depends on DEBUG_KERNEL && PROC_FS
	71	help
	72	If you say Y here, additional code will be inserted into the
	73	scheduler and related routines to collect statistics about
	74	scheduler behavior and provide them in /proc/schedstat. These
	75	stats may be useful for both tuning and debugging the scheduler
	76	If you aren't debugging the scheduler or trying to tune a specific
	77	application, you can say N to avoid the very slight overhead
	78	this adds.
	79
	80	config DEBUG_SLAB
4a2f0acf	81	bool "Debug slab memory allocations"
50dd26ba	82	depends on DEBUG_KERNEL && SLAB
1da177e4 LT	83	help
	84	Say Y here to have the kernel do limited verification on memory
	85	allocation as well as poisoning memory on free to catch use of freed
	86	memory. This can make kmalloc/kfree-intensive workloads much slower.
	87
871751e2 AV	88	config DEBUG_SLAB_LEAK
	89	bool "Memory leak debugging"
	90	depends on DEBUG_SLAB
	91
1da177e4 LT	92	config DEBUG_PREEMPT
	93	bool "Debug preemptible kernel"
	94	depends on DEBUG_KERNEL && PREEMPT
	95	default y
	96	help
	97	If you say Y here then the kernel will use a debug variant of the
	98	commonly used smp_processor_id() function and will print warnings
	99	if kernel code uses it in a preemption-unsafe way. Also, the kernel
	100	will detect preemption count underflows.
	101
408894ee IM	102	config DEBUG_MUTEXES
408894ee IM	103	bool "Mutex debugging, deadlock detection"
cca57c5b	104	default n
408894ee IM	105	depends on DEBUG_KERNEL
	106	help
	107	This allows mutex semantics violations and mutex related deadlocks
	108	(lockups) to be detected and reported automatically.
	109
e7eebaf6 IM	110	config DEBUG_RT_MUTEXES
	111	bool "RT Mutex debugging, deadlock detection"
	112	default y
	113	depends on DEBUG_KERNEL && RT_MUTEXES
	114	help
	115	This allows rt mutex semantics violations and rt mutex related
	116	deadlocks (lockups) to be detected and reported automatically.
	117
	118	config DEBUG_PI_LIST
	119	bool
	120	default y
	121	depends on DEBUG_RT_MUTEXES
	122
61a87122 TG	123	config RT_MUTEX_TESTER
	124	bool "Built-in scriptable tester for rt-mutexes"
	125	depends on RT_MUTEXES
	126	default n
	127	help
	128	This option enables a rt-mutex tester.
	129
1da177e4 LT	130	config DEBUG_SPINLOCK
	131	bool "Spinlock debugging"
	132	depends on DEBUG_KERNEL
	133	help
	134	Say Y here and build SMP to catch missing spinlock initialization
	135	and certain other kinds of spinlock errors commonly made. This is
	136	best used in conjunction with the NMI watchdog so that spinlock
	137	deadlocks are also debuggable.
	138
	139	config DEBUG_SPINLOCK_SLEEP
	140	bool "Sleep-inside-spinlock checking"
	141	depends on DEBUG_KERNEL
	142	help
	143	If you say Y here, various routines which may sleep will become very
	144	noisy if they are called with a spinlock held.
	145
	146	config DEBUG_KOBJECT
	147	bool "kobject debugging"
	148	depends on DEBUG_KERNEL
	149	help
	150	If you say Y here, some extra kobject debugging messages will be sent
	151	to the syslog.
	152
	153	config DEBUG_HIGHMEM
	154	bool "Highmem debugging"
	155	depends on DEBUG_KERNEL && HIGHMEM
	156	help
	157	This options enables addition error checking for high memory systems.
	158	Disable for production systems.
	159
	160	config DEBUG_BUGVERBOSE
	161	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
c8538a7a	162	depends on BUG
0d078f6f	163	depends on ARM \|\| ARM26 \|\| M32R \|\| M68K \|\| SPARC32 \|\| SPARC64 \|\| X86_32 \|\| FRV
1da177e4 LT	164	default !EMBEDDED
	165	help
	166	Say Y here to make BUG() panics output the file name and line number
	167	of the BUG call as well as the EIP and oops trace. This aids
	168	debugging but costs about 70-100K of memory.
	169
	170	config DEBUG_INFO
	171	bool "Compile the kernel with debug info"
	172	depends on DEBUG_KERNEL
	173	help
	174	If you say Y here the resulting kernel image will include
	175	debugging info resulting in a larger kernel image.
	176	Say Y here only if you plan to debug the kernel.
	177
	178	If unsure, say N.
	179
1da177e4 LT	180	config DEBUG_FS
1da177e4 LT	181	bool "Debug Filesystem"
ae36b883	182	depends on SYSFS
1da177e4 LT	183	help
	184	debugfs is a virtual file system that kernel developers use to put
	185	debugging files into. Enable this option to be able to read and
	186	write to these files.
	187
	188	If unsure, say N.
	189
a241ec65 PM	190	config DEBUG_VM
	191	bool "Debug VM"
	192	depends on DEBUG_KERNEL
	193	help
13e7444b NP	194	Enable this to turn on extended checks in the virtual-memory system
13e7444b NP	195	that may impact performance.
a241ec65 PM	196
	197	If unsure, say N.
	198
1da177e4 LT	199	config FRAME_POINTER
1da177e4 LT	200	bool "Compile the kernel with frame pointers"
aeb39986	201	depends on DEBUG_KERNEL && (X86 \|\| CRIS \|\| M68K \|\| M68KNOMMU \|\| FRV \|\| UML)
37fce857	202	default y if DEBUG_INFO && UML
1da177e4 LT	203	help
1da177e4 LT	204	If you say Y here the resulting kernel image will be slightly larger
2a38bccd JJ	205	and slower, but it might give very useful debugging information on
2a38bccd JJ	206	some architectures or if you use external debuggers.
aeb39986	207	If you don't debug the kernel, you can say N.
1da177e4	208
604bf5a2 JB	209	config UNWIND_INFO
604bf5a2 JB	210	bool "Compile the kernel with frame unwind information"
4552d5dc JB	211	depends on !IA64 && !PARISC
4552d5dc JB	212	depends on !MODULES \|\| !(MIPS \|\| PPC \|\| SUPERH \|\| V850)
604bf5a2 JB	213	help
	214	If you say Y here the resulting kernel image will be slightly larger
	215	but not slower, and it will give very useful debugging information.
	216	If you don't debug the kernel, you can say N, but we may not be able
	217	to solve problems without frame unwind information or frame pointers.
	218
4552d5dc JB	219	config STACK_UNWIND
	220	bool "Stack unwind support"
	221	depends on UNWIND_INFO
176a2718	222	depends on X86
4552d5dc JB	223	help
	224	This enables more precise stack traces, omitting all unrelated
	225	occurrences of pointers into kernel code from the dump.
	226
a9df3d0f IM	227	config FORCED_INLINING
	228	bool "Force gcc to inline functions marked 'inline'"
	229	depends on DEBUG_KERNEL
	230	default y
	231	help
	232	This option determines if the kernel forces gcc to inline the functions
	233	developers have marked 'inline'. Doing so takes away freedom from gcc to
	234	do what it thinks is best, which is desirable for the gcc 3.x series of
	235	compilers. The gcc 4.x series have a rewritten inlining algorithm and
	236	disabling this option will generate a smaller kernel there. Hopefully
	237	this algorithm is so good that allowing gcc4 to make the decision can
	238	become the default in the future, until then this option is there to
	239	test gcc for this.
	240
a241ec65 PM	241	config RCU_TORTURE_TEST
	242	tristate "torture tests for RCU"
	243	depends on DEBUG_KERNEL
	244	default n
	245	help
	246	This option provides a kernel module that runs torture tests
	247	on the RCU infrastructure. The kernel module may be built
	248	after the fact on the running kernel to be tested, if desired.
	249
	250	Say Y here if you want RCU torture tests to start automatically
	251	at boot time (you probably don't).
	252	Say M if you want the RCU torture tests to build as a module.
	253	Say N if you are unsure.