[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 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 y
	depends on DEBUG_KERNEL
	help
	 This allows mutex semantics violations and mutex related deadlocks
	 (lockups) to be detected and reported automatically.

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_IOREMAP
	bool "Enable ioremap() debugging"
	depends on DEBUG_KERNEL && PARISC
	help
	  Enabling this option will cause the kernel to distinguish between
	  ioremapped and physical addresses.  It will print a backtrace (at
	  most one every 10 seconds), hopefully allowing you to see which
	  drivers need work.  Fixing all these problems is a prerequisite
	  for turning on USE_HPPA_IOREMAP.  The warnings are harmless;
	  the kernel has enough information to fix the broken drivers
	  automatically, but we'd like to make it more efficient by not
	  having to do that.

config DEBUG_FS
	bool "Debug Filesystem"
	depends on DEBUG_KERNEL && 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
	depends on !MODULES || !(MIPS || PARISC || PPC || SUPERH || SPARC64 || V850)
	default DEBUG_KERNEL
	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 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
	81	bool "Debug 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
	103	bool "Mutex debugging, deadlock detection"
	104	default y
	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
1da177e4 LT	110	config DEBUG_SPINLOCK
	111	bool "Spinlock debugging"
	112	depends on DEBUG_KERNEL
	113	help
	114	Say Y here and build SMP to catch missing spinlock initialization
	115	and certain other kinds of spinlock errors commonly made. This is
	116	best used in conjunction with the NMI watchdog so that spinlock
	117	deadlocks are also debuggable.
	118
	119	config DEBUG_SPINLOCK_SLEEP
	120	bool "Sleep-inside-spinlock checking"
	121	depends on DEBUG_KERNEL
	122	help
	123	If you say Y here, various routines which may sleep will become very
	124	noisy if they are called with a spinlock held.
	125
	126	config DEBUG_KOBJECT
	127	bool "kobject debugging"
	128	depends on DEBUG_KERNEL
	129	help
	130	If you say Y here, some extra kobject debugging messages will be sent
	131	to the syslog.
	132
	133	config DEBUG_HIGHMEM
	134	bool "Highmem debugging"
	135	depends on DEBUG_KERNEL && HIGHMEM
	136	help
	137	This options enables addition error checking for high memory systems.
	138	Disable for production systems.
	139
	140	config DEBUG_BUGVERBOSE
	141	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
c8538a7a	142	depends on BUG
0d078f6f	143	depends on ARM \|\| ARM26 \|\| M32R \|\| M68K \|\| SPARC32 \|\| SPARC64 \|\| X86_32 \|\| FRV
1da177e4 LT	144	default !EMBEDDED
	145	help
	146	Say Y here to make BUG() panics output the file name and line number
	147	of the BUG call as well as the EIP and oops trace. This aids
	148	debugging but costs about 70-100K of memory.
	149
	150	config DEBUG_INFO
	151	bool "Compile the kernel with debug info"
	152	depends on DEBUG_KERNEL
	153	help
	154	If you say Y here the resulting kernel image will include
	155	debugging info resulting in a larger kernel image.
	156	Say Y here only if you plan to debug the kernel.
	157
	158	If unsure, say N.
	159
	160	config DEBUG_IOREMAP
	161	bool "Enable ioremap() debugging"
	162	depends on DEBUG_KERNEL && PARISC
	163	help
	164	Enabling this option will cause the kernel to distinguish between
	165	ioremapped and physical addresses. It will print a backtrace (at
	166	most one every 10 seconds), hopefully allowing you to see which
	167	drivers need work. Fixing all these problems is a prerequisite
	168	for turning on USE_HPPA_IOREMAP. The warnings are harmless;
	169	the kernel has enough information to fix the broken drivers
	170	automatically, but we'd like to make it more efficient by not
	171	having to do that.
	172
	173	config DEBUG_FS
	174	bool "Debug Filesystem"
3348e05a	175	depends on DEBUG_KERNEL && SYSFS
1da177e4 LT	176	help
	177	debugfs is a virtual file system that kernel developers use to put
	178	debugging files into. Enable this option to be able to read and
	179	write to these files.
	180
	181	If unsure, say N.
	182
a241ec65 PM	183	config DEBUG_VM
	184	bool "Debug VM"
	185	depends on DEBUG_KERNEL
	186	help
13e7444b NP	187	Enable this to turn on extended checks in the virtual-memory system
13e7444b NP	188	that may impact performance.
a241ec65 PM	189
	190	If unsure, say N.
	191
1da177e4 LT	192	config FRAME_POINTER
1da177e4 LT	193	bool "Compile the kernel with frame pointers"
aeb39986	194	depends on DEBUG_KERNEL && (X86 \|\| CRIS \|\| M68K \|\| M68KNOMMU \|\| FRV \|\| UML)
37fce857	195	default y if DEBUG_INFO && UML
1da177e4 LT	196	help
1da177e4 LT	197	If you say Y here the resulting kernel image will be slightly larger
2a38bccd JJ	198	and slower, but it might give very useful debugging information on
2a38bccd JJ	199	some architectures or if you use external debuggers.
aeb39986	200	If you don't debug the kernel, you can say N.
1da177e4	201
604bf5a2 JB	202	config UNWIND_INFO
	203	bool "Compile the kernel with frame unwind information"
	204	depends on !IA64
	205	depends on !MODULES \|\| !(MIPS \|\| PARISC \|\| PPC \|\| SUPERH \|\| SPARC64 \|\| V850)
	206	default DEBUG_KERNEL
	207	help
	208	If you say Y here the resulting kernel image will be slightly larger
	209	but not slower, and it will give very useful debugging information.
	210	If you don't debug the kernel, you can say N, but we may not be able
	211	to solve problems without frame unwind information or frame pointers.
	212
a9df3d0f IM	213	config FORCED_INLINING
	214	bool "Force gcc to inline functions marked 'inline'"
	215	depends on DEBUG_KERNEL
	216	default y
	217	help
	218	This option determines if the kernel forces gcc to inline the functions
	219	developers have marked 'inline'. Doing so takes away freedom from gcc to
	220	do what it thinks is best, which is desirable for the gcc 3.x series of
	221	compilers. The gcc 4.x series have a rewritten inlining algorithm and
	222	disabling this option will generate a smaller kernel there. Hopefully
	223	this algorithm is so good that allowing gcc4 to make the decision can
	224	become the default in the future, until then this option is there to
	225	test gcc for this.
	226
a241ec65 PM	227	config RCU_TORTURE_TEST
	228	tristate "torture tests for RCU"
	229	depends on DEBUG_KERNEL
	230	default n
	231	help
	232	This option provides a kernel module that runs torture tests
	233	on the RCU infrastructure. The kernel module may be built
	234	after the fact on the running kernel to be tested, if desired.
	235
	236	Say Y here if you want RCU torture tests to start automatically
	237	at boot time (you probably don't).
	238	Say M if you want the RCU torture tests to build as a module.
	239	Say N if you are unsure.