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| author | Steven Rostedt <srostedt@redhat.com> | 2013-01-11 16:14:10 -0500 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2013-01-11 16:14:10 -0500 |
| commit | 2df8f8a6a897ebf4c5613b5be6103d33b2a21520 (patch) | |
| tree | a79d468ef6e2b41392dca68c9319f73a99a51770 /kernel | |
| parent | a8dd2176a8e988e3744e863ac39647a6f59fa900 (diff) | |
| download | linux-2df8f8a6a897ebf4c5613b5be6103d33b2a21520.tar.gz linux-2df8f8a6a897ebf4c5613b5be6103d33b2a21520.tar.bz2 linux-2df8f8a6a897ebf4c5613b5be6103d33b2a21520.zip | |
tracing: Fix regression with irqsoff tracer and tracing_on file
Commit 02404baf1b47 "tracing: Remove deprecated tracing_enabled file"
removed the tracing_enabled file as it never worked properly and
the tracing_on file should be used instead. But the tracing_on file
didn't call into the tracers start/stop routines like the
tracing_enabled file did. This caused trace-cmd to break when it
enabled the irqsoff tracer.
If you just did "echo irqsoff > current_tracer" then it would work
properly. But the tool trace-cmd disables tracing first by writing
"0" into the tracing_on file. Then it writes "irqsoff" into
current_tracer and then writes "1" into tracing_on. Unfortunately,
the above commit changed the irqsoff tracer to check the tracing_on
status instead of the tracing_enabled status. If it's disabled then
it does not start the tracer internals.
The problem is that writing "1" into tracing_on does not call the
tracers "start" routine like writing "1" into tracing_enabled did.
This makes the irqsoff tracer not start when using the trace-cmd
tool, and is a regression for userspace.
Simple fix is to have the tracing_on file call the tracers start()
method when being enabled (and the stop() method when disabled).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 1bbfa0446507..f3ec1cfb0de1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4817,10 +4817,17 @@ rb_simple_write(struct file *filp, const char __user *ubuf, return ret; if (buffer) { - if (val) + mutex_lock(&trace_types_lock); + if (val) { ring_buffer_record_on(buffer); - else + if (current_trace->start) + current_trace->start(tr); + } else { ring_buffer_record_off(buffer); + if (current_trace->stop) + current_trace->stop(tr); + } + mutex_unlock(&trace_types_lock); } (*ppos)++; |