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author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-03-30 07:04:53 +0400 |
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committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-03-30 07:04:53 +0400 |
commit | 9ff9a26b786c35ee8d2a66222924a807ec851a9f (patch) | |
tree | db432a17bccca1ca2c16907f0ee83ac449ed4012 /lib/Kconfig.debug | |
parent | 0a3108beea9143225119d5e7c72a8e2c64f3eb7d (diff) | |
parent | 0d34fb8e93ceba7b6dad0062dbb4a0813bacd75b (diff) | |
download | linux-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.debug | 76 |
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" |