+menu "printk and dmesg options"
config PRINTK_TIME
bool "Show timing information on printks"
that are auditing their logs closely may want to set it to a lower
priority.
+config BOOT_PRINTK_DELAY
+ bool "Delay each boot printk message by N milliseconds"
+ depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
+ help
+ This build option allows you to read kernel boot messages
+ by inserting a short delay after each one. The delay is
+ specified in milliseconds on the kernel command line,
+ using "boot_delay=N".
+
+ It is likely that you would also need to use "lpj=M" to preset
+ the "loops per jiffie" value.
+ See a previous boot log for the "lpj" value to use for your
+ system, and then set "lpj=M" before setting "boot_delay=N".
+ NOTE: Using this option may adversely affect SMP systems.
+ I.e., processors other than the first one may not boot up.
+ BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
+ what it believes to be lockup conditions.
+
+config DYNAMIC_DEBUG
+ bool "Enable dynamic printk() support"
+ default n
+ depends on PRINTK
+ depends on DEBUG_FS
+ help
+
+ Compiles debug level messages into the kernel, which would not
+ otherwise be available at runtime. These messages can then be
+ enabled/disabled based on various levels of scope - per source file,
+ function, module, format string, and line number. This mechanism
+ implicitly compiles in all pr_debug() and dev_dbg() calls, which
+ enlarges the kernel text size by about 2%.
+
+ If a source file is compiled with DEBUG flag set, any
+ pr_debug() calls in it are enabled by default, but can be
+ disabled at runtime as below. Note that DEBUG flag is
+ turned on by many CONFIG_*DEBUG* options.
+
+ Usage:
+
+ Dynamic debugging is controlled via the 'dynamic_debug/control' file,
+ which is contained in the 'debugfs' filesystem. Thus, the debugfs
+ filesystem must first be mounted before making use of this feature.
+ We refer the control file as: <debugfs>/dynamic_debug/control. This
+ file contains a list of the debug statements that can be enabled. The
+ format for each line of the file is:
+
+ filename:lineno [module]function flags format
+
+ filename : source file of the debug statement
+ lineno : line number of the debug statement
+ module : module that contains the debug statement
+ function : function that contains the debug statement
+ flags : '=p' means the line is turned 'on' for printing
+ format : the format used for the debug statement
+
+ From a live system:
+
+ nullarbor:~ # cat <debugfs>/dynamic_debug/control
+ # filename:lineno [module]function flags format
+ fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
+ fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
+ fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
+
+ Example usage:
+
+ // enable the message at line 1603 of file svcsock.c
+ nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable all the messages in file svcsock.c
+ nullarbor:~ # echo -n 'file svcsock.c +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable all the messages in the NFS server module
+ nullarbor:~ # echo -n 'module nfsd +p' >
+ <debugfs>/dynamic_debug/control
+
+ // enable all 12 messages in the function svc_process()
+ nullarbor:~ # echo -n 'func svc_process +p' >
+ <debugfs>/dynamic_debug/control
+
+ // disable all 12 messages in the function svc_process()
+ nullarbor:~ # echo -n 'func svc_process -p' >
+ <debugfs>/dynamic_debug/control
+
+ See Documentation/dynamic-debug-howto.txt for additional information.
+
+endmenu # "printk and dmesg options"
+
menu "Compile-time checks and compiler options"
config DEBUG_INFO
Drivers ought to be able to handle interrupts coming in at those
points; some don't and need to be caught.
+menu "Debug Lockups and Hangs"
+
config LOCKUP_DETECTOR
bool "Detect Hard and Soft Lockups"
depends on DEBUG_KERNEL && !S390
default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC
default 1 if BOOTPARAM_SOFTLOCKUP_PANIC
-config PANIC_ON_OOPS
- bool "Panic on Oops"
- help
- Say Y here to enable the kernel to panic when it oopses. This
- has the same effect as setting oops=panic on the kernel command
- line.
-
- This feature is useful to ensure that the kernel does not do
- anything erroneous after an oops which could result in data
- corruption or other issues.
-
- Say N if unsure.
-
-config PANIC_ON_OOPS_VALUE
- int
- range 0 1
- default 0 if !PANIC_ON_OOPS
- default 1 if PANIC_ON_OOPS
-
config DETECT_HUNG_TASK
bool "Detect Hung Tasks"
depends on DEBUG_KERNEL
default 0 if !BOOTPARAM_HUNG_TASK_PANIC
default 1 if BOOTPARAM_HUNG_TASK_PANIC
+endmenu # "Debug lockups and hangs"
+
+config PANIC_ON_OOPS
+ bool "Panic on Oops"
+ help
+ Say Y here to enable the kernel to panic when it oopses. This
+ has the same effect as setting oops=panic on the kernel command
+ line.
+
+ This feature is useful to ensure that the kernel does not do
+ anything erroneous after an oops which could result in data
+ corruption or other issues.
+
+ Say N if unsure.
+
+config PANIC_ON_OOPS_VALUE
+ int
+ range 0 1
+ default 0 if !PANIC_ON_OOPS
+ default 1 if PANIC_ON_OOPS
+
config SCHED_DEBUG
bool "Collect scheduler debugging info"
depends on DEBUG_KERNEL && PROC_FS
This feature allows mutex semantics violations to be detected and
reported.
+config DEBUG_WW_MUTEX_SLOWPATH
+ bool "Wait/wound mutex debugging: Slowpath testing"
+ depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
+ select DEBUG_LOCK_ALLOC
+ select DEBUG_SPINLOCK
+ select DEBUG_MUTEXES
+ help
+ This feature enables slowpath testing for w/w mutex users by
+ injecting additional -EDEADLK wound/backoff cases. Together with
+ the full mutex checks enabled with (CONFIG_PROVE_LOCKING) this
+ will test all possible w/w mutex interface abuse with the
+ exception of simply not acquiring all the required locks.
+
config DEBUG_LOCK_ALLOC
bool "Lock debugging: detect incorrect freeing of live locks"
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
If unsure, say N.
-config BOOT_PRINTK_DELAY
- bool "Delay each boot printk message by N milliseconds"
- depends on DEBUG_KERNEL && PRINTK && GENERIC_CALIBRATE_DELAY
- help
- This build option allows you to read kernel boot messages
- by inserting a short delay after each one. The delay is
- specified in milliseconds on the kernel command line,
- using "boot_delay=N".
-
- It is likely that you would also need to use "lpj=M" to preset
- the "loops per jiffie" value.
- See a previous boot log for the "lpj" value to use for your
- system, and then set "lpj=M" before setting "boot_delay=N".
- NOTE: Using this option may adversely affect SMP systems.
- I.e., processors other than the first one may not boot up.
- BOOT_PRINTK_DELAY also may cause LOCKUP_DETECTOR to detect
- what it believes to be lockup conditions.
-
menu "RCU Debugging"
config PROVE_RCU
Say N if you are unsure.
-config DYNAMIC_DEBUG
- bool "Enable dynamic printk() support"
- default n
- depends on PRINTK
- depends on DEBUG_FS
- help
-
- Compiles debug level messages into the kernel, which would not
- otherwise be available at runtime. These messages can then be
- enabled/disabled based on various levels of scope - per source file,
- function, module, format string, and line number. This mechanism
- implicitly compiles in all pr_debug() and dev_dbg() calls, which
- enlarges the kernel text size by about 2%.
-
- If a source file is compiled with DEBUG flag set, any
- pr_debug() calls in it are enabled by default, but can be
- disabled at runtime as below. Note that DEBUG flag is
- turned on by many CONFIG_*DEBUG* options.
-
- Usage:
-
- Dynamic debugging is controlled via the 'dynamic_debug/control' file,
- which is contained in the 'debugfs' filesystem. Thus, the debugfs
- filesystem must first be mounted before making use of this feature.
- We refer the control file as: <debugfs>/dynamic_debug/control. This
- file contains a list of the debug statements that can be enabled. The
- format for each line of the file is:
-
- filename:lineno [module]function flags format
-
- filename : source file of the debug statement
- lineno : line number of the debug statement
- module : module that contains the debug statement
- function : function that contains the debug statement
- flags : '=p' means the line is turned 'on' for printing
- format : the format used for the debug statement
-
- From a live system:
-
- nullarbor:~ # cat <debugfs>/dynamic_debug/control
- # filename:lineno [module]function flags format
- fs/aio.c:222 [aio]__put_ioctx =_ "__put_ioctx:\040freeing\040%p\012"
- fs/aio.c:248 [aio]ioctx_alloc =_ "ENOMEM:\040nr_events\040too\040high\012"
- fs/aio.c:1770 [aio]sys_io_cancel =_ "calling\040cancel\012"
-
- Example usage:
-
- // enable the message at line 1603 of file svcsock.c
- nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
- <debugfs>/dynamic_debug/control
-
- // enable all the messages in file svcsock.c
- nullarbor:~ # echo -n 'file svcsock.c +p' >
- <debugfs>/dynamic_debug/control
-
- // enable all the messages in the NFS server module
- nullarbor:~ # echo -n 'module nfsd +p' >
- <debugfs>/dynamic_debug/control
-
- // enable all 12 messages in the function svc_process()
- nullarbor:~ # echo -n 'func svc_process +p' >
- <debugfs>/dynamic_debug/control
-
- // disable all 12 messages in the function svc_process()
- nullarbor:~ # echo -n 'func svc_process -p' >
- <debugfs>/dynamic_debug/control
-
- See Documentation/dynamic-debug-howto.txt for additional information.
-
config DMA_API_DEBUG
bool "Enable debugging of DMA-API usage"
depends on HAVE_DMA_API_DEBUG
projects / cascardo / linux.git / blobdiff