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| author | Steven Rostedt <srostedt@redhat.com> | 2008-11-21 12:59:38 -0500 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-11-23 11:45:34 +0100 |
| commit | 69bb54ec05f57da7f6fac2cec0820cbc970df20f (patch) | |
| tree | cdee5802117c2e78cf18df7fa524c7390d1bdb67 | |
| parent | e58918ab9d4cd375f6d842e6d88cf4d7a55cbfcc (diff) | |
| download | op-kernel-dev-69bb54ec05f57da7f6fac2cec0820cbc970df20f.zip op-kernel-dev-69bb54ec05f57da7f6fac2cec0820cbc970df20f.tar.gz | |
ftrace: add ftrace_off_permanent
Impact: add new API to disable all of ftrace on anomalies
It case of a serious anomaly being detected (like something caught by
lockdep) it is a good idea to disable all tracing immediately, without
grabing any locks.
This patch adds ftrace_off_permanent that disables the tracers, function
tracing and ring buffers without a way to enable them again. This should
only be used when something serious has been detected.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/linux/ftrace.h | 2 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 15 |
2 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index f7ba4ea..13e9cfc 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -257,6 +257,7 @@ extern int ftrace_dump_on_oops; extern void tracing_start(void); extern void tracing_stop(void); +extern void ftrace_off_permanent(void); extern void ftrace_special(unsigned long arg1, unsigned long arg2, unsigned long arg3); @@ -290,6 +291,7 @@ ftrace_printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 0))); static inline void tracing_start(void) { } static inline void tracing_stop(void) { } +static inline void ftrace_off_permanent(void) { } static inline int ftrace_printk(const char *fmt, ...) { diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4ee6f037..0dbfb23 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -661,6 +661,21 @@ static int trace_stop_count; static DEFINE_SPINLOCK(tracing_start_lock); /** + * ftrace_off_permanent - disable all ftrace code permanently + * + * This should only be called when a serious anomally has + * been detected. This will turn off the function tracing, + * ring buffers, and other tracing utilites. It takes no + * locks and can be called from any context. + */ +void ftrace_off_permanent(void) +{ + tracing_disabled = 1; + ftrace_stop(); + tracing_off_permanent(); +} + +/** * tracing_start - quick start of the tracer * * If tracing is enabled but was stopped by tracing_stop, |
