[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_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 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
	88	config DEBUG_PREEMPT
	89	bool "Debug preemptible kernel"
	90	depends on DEBUG_KERNEL && PREEMPT
	91	default y
	92	help
	93	If you say Y here then the kernel will use a debug variant of the
	94	commonly used smp_processor_id() function and will print warnings
	95	if kernel code uses it in a preemption-unsafe way. Also, the kernel
	96	will detect preemption count underflows.
	97
408894ee IM	98	config DEBUG_MUTEXES
	99	bool "Mutex debugging, deadlock detection"
	100	default y
	101	depends on DEBUG_KERNEL
	102	help
	103	This allows mutex semantics violations and mutex related deadlocks
	104	(lockups) to be detected and reported automatically.
	105
1da177e4 LT	106	config DEBUG_SPINLOCK
	107	bool "Spinlock debugging"
	108	depends on DEBUG_KERNEL
	109	help
	110	Say Y here and build SMP to catch missing spinlock initialization
	111	and certain other kinds of spinlock errors commonly made. This is
	112	best used in conjunction with the NMI watchdog so that spinlock
	113	deadlocks are also debuggable.
	114
	115	config DEBUG_SPINLOCK_SLEEP
	116	bool "Sleep-inside-spinlock checking"
	117	depends on DEBUG_KERNEL
	118	help
	119	If you say Y here, various routines which may sleep will become very
	120	noisy if they are called with a spinlock held.
	121
	122	config DEBUG_KOBJECT
	123	bool "kobject debugging"
	124	depends on DEBUG_KERNEL
	125	help
	126	If you say Y here, some extra kobject debugging messages will be sent
	127	to the syslog.
	128
	129	config DEBUG_HIGHMEM
	130	bool "Highmem debugging"
	131	depends on DEBUG_KERNEL && HIGHMEM
	132	help
	133	This options enables addition error checking for high memory systems.
	134	Disable for production systems.
	135
	136	config DEBUG_BUGVERBOSE
	137	bool "Verbose BUG() reporting (adds 70K)" if DEBUG_KERNEL && EMBEDDED
c8538a7a	138	depends on BUG
0d078f6f	139	depends on ARM \|\| ARM26 \|\| M32R \|\| M68K \|\| SPARC32 \|\| SPARC64 \|\| X86_32 \|\| FRV
1da177e4 LT	140	default !EMBEDDED
	141	help
	142	Say Y here to make BUG() panics output the file name and line number
	143	of the BUG call as well as the EIP and oops trace. This aids
	144	debugging but costs about 70-100K of memory.
	145
	146	config DEBUG_INFO
	147	bool "Compile the kernel with debug info"
	148	depends on DEBUG_KERNEL
	149	help
	150	If you say Y here the resulting kernel image will include
	151	debugging info resulting in a larger kernel image.
	152	Say Y here only if you plan to debug the kernel.
	153
	154	If unsure, say N.
	155
	156	config DEBUG_IOREMAP
	157	bool "Enable ioremap() debugging"
	158	depends on DEBUG_KERNEL && PARISC
	159	help
	160	Enabling this option will cause the kernel to distinguish between
	161	ioremapped and physical addresses. It will print a backtrace (at
	162	most one every 10 seconds), hopefully allowing you to see which
	163	drivers need work. Fixing all these problems is a prerequisite
	164	for turning on USE_HPPA_IOREMAP. The warnings are harmless;
	165	the kernel has enough information to fix the broken drivers
	166	automatically, but we'd like to make it more efficient by not
	167	having to do that.
	168
	169	config DEBUG_FS
	170	bool "Debug Filesystem"
3348e05a	171	depends on DEBUG_KERNEL && SYSFS
1da177e4 LT	172	help
	173	debugfs is a virtual file system that kernel developers use to put
	174	debugging files into. Enable this option to be able to read and
	175	write to these files.
	176
	177	If unsure, say N.
	178
a241ec65 PM	179	config DEBUG_VM
	180	bool "Debug VM"
	181	depends on DEBUG_KERNEL
	182	help
13e7444b NP	183	Enable this to turn on extended checks in the virtual-memory system
13e7444b NP	184	that may impact performance.
a241ec65 PM	185
	186	If unsure, say N.
	187
1da177e4 LT	188	config FRAME_POINTER
1da177e4 LT	189	bool "Compile the kernel with frame pointers"
aeb39986	190	depends on DEBUG_KERNEL && (X86 \|\| CRIS \|\| M68K \|\| M68KNOMMU \|\| FRV \|\| UML)
37fce857	191	default y if DEBUG_INFO && UML
1da177e4 LT	192	help
1da177e4 LT	193	If you say Y here the resulting kernel image will be slightly larger
2a38bccd JJ	194	and slower, but it might give very useful debugging information on
2a38bccd JJ	195	some architectures or if you use external debuggers.
aeb39986	196	If you don't debug the kernel, you can say N.
1da177e4	197
a241ec65 PM	198	config RCU_TORTURE_TEST
	199	tristate "torture tests for RCU"
	200	depends on DEBUG_KERNEL
	201	default n
	202	help
	203	This option provides a kernel module that runs torture tests
	204	on the RCU infrastructure. The kernel module may be built
	205	after the fact on the running kernel to be tested, if desired.
	206
	207	Say Y here if you want RCU torture tests to start automatically
	208	at boot time (you probably don't).
	209	Say M if you want the RCU torture tests to build as a module.
	210	Say N if you are unsure.