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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-03-30 07:04:53 +0400
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2009-03-30 07:04:53 +0400
commit9ff9a26b786c35ee8d2a66222924a807ec851a9f (patch)
treedb432a17bccca1ca2c16907f0ee83ac449ed4012 /lib/Kconfig.debug
parent0a3108beea9143225119d5e7c72a8e2c64f3eb7d (diff)
parent0d34fb8e93ceba7b6dad0062dbb4a0813bacd75b (diff)
downloadlinux-9ff9a26b786c35ee8d2a66222924a807ec851a9f.tar.xz
Merge commit 'origin/master' into next
Manual merge of: arch/powerpc/include/asm/elf.h drivers/i2c/busses/i2c-mpc.c
Diffstat (limited to 'lib/Kconfig.debug')
-rw-r--r--lib/Kconfig.debug76
1 files changed, 43 insertions, 33 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 1bcf9cd4baa0..0626fa4856e6 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -402,7 +402,7 @@ config LOCKDEP
bool
depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
select STACKTRACE
- select FRAME_POINTER if !X86 && !MIPS && !PPC
+ select FRAME_POINTER if !X86 && !MIPS && !PPC && !ARM_UNWIND
select KALLSYMS
select KALLSYMS_ALL
@@ -847,60 +847,70 @@ config BUILD_DOCSRC
Say N if you are unsure.
-config DYNAMIC_PRINTK_DEBUG
- bool "Enable dynamic printk() call support"
+config DYNAMIC_DEBUG
+ bool "Enable dynamic printk() support"
default n
depends on PRINTK
+ depends on DEBUG_FS
select PRINTK_DEBUG
help
Compiles debug level messages into the kernel, which would not
otherwise be available at runtime. These messages can then be
- enabled/disabled on a per module basis. This mechanism implicitly
- enables all pr_debug() and dev_dbg() calls. The impact of this
- compile option is a larger kernel text size of about 2%.
+ enabled/disabled based on various levels of scope - per source file,
+ function, module, format string, and line number. This mechanism
+ implicitly enables all pr_debug() and dev_dbg() calls. The impact of
+ this compile option is a larger kernel text size of about 2%.
Usage:
- Dynamic debugging is controlled by the debugfs file,
- dynamic_printk/modules. This file contains a list of the modules that
- can be enabled. The format of the file is the module name, followed
- by a set of flags that can be enabled. The first flag is always the
- 'enabled' flag. For example:
+ Dynamic debugging is controlled via the 'dynamic_debug/ddebug' 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/ddebug. This
+ file contains a list of the debug statements that can be enabled. The
+ format for each line of the file is:
- <module_name> <enabled=0/1>
- .
- .
- .
+ filename:lineno [module]function flags format
- <module_name> : Name of the module in which the debug call resides
- <enabled=0/1> : whether the messages are enabled or not
+ 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:
- snd_hda_intel enabled=0
- fixup enabled=0
- driver enabled=0
+ nullarbor:~ # cat <debugfs>/dynamic_debug/ddebug
+ # 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"
- Enable a module:
+ Example usage:
- $echo "set enabled=1 <module_name>" > dynamic_printk/modules
+ // enable the message at line 1603 of file svcsock.c
+ nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
+ <debugfs>/dynamic_debug/ddebug
- Disable a module:
+ // enable all the messages in file svcsock.c
+ nullarbor:~ # echo -n 'file svcsock.c +p' >
+ <debugfs>/dynamic_debug/ddebug
- $echo "set enabled=0 <module_name>" > dynamic_printk/modules
+ // enable all the messages in the NFS server module
+ nullarbor:~ # echo -n 'module nfsd +p' >
+ <debugfs>/dynamic_debug/ddebug
- Enable all modules:
+ // enable all 12 messages in the function svc_process()
+ nullarbor:~ # echo -n 'func svc_process +p' >
+ <debugfs>/dynamic_debug/ddebug
- $echo "set enabled=1 all" > dynamic_printk/modules
+ // disable all 12 messages in the function svc_process()
+ nullarbor:~ # echo -n 'func svc_process -p' >
+ <debugfs>/dynamic_debug/ddebug
- Disable all modules:
-
- $echo "set enabled=0 all" > dynamic_printk/modules
-
- Finally, passing "dynamic_printk" at the command line enables
- debugging for all modules. This mode can be turned off via the above
- disable command.
+ See Documentation/dynamic-debug-howto.txt for additional information.
source "samples/Kconfig"