[tip:tracing/tasks] tracing: stop command line recording when tracing is disabled

[Thomas Gleixner]

Commit-ID:  18aecd362a1c991fbf5f7919ae051a77532ba2f8
Gitweb:     http://git.kernel.org/tip/18aecd362a1c991fbf5f7919ae051a77532ba2f8
Author:     Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Wed, 18 Mar 2009 08:56:58 +0100
Commit:     Ingo Molnar <mingo@xxxxxxx>
CommitDate: Wed, 18 Mar 2009 10:10:16 +0100

tracing: stop command line recording when tracing is disabled

Impact: prevent overwrite of command line entries

When the tracer is stopped the command line recording continues to
record. The check for tracing_is_on() is not sufficient here as the
ringbuffer status is not affected by setting
debug/tracing/tracing_enabled to 0. On a non idle system this can
result in the loss of the command line information for the stopped
trace, which makes the trace harder to read and analyse.

Check tracer_enabled to allow further recording.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Steven Rostedt <srostedt@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
 kernel/trace/trace.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1ce6208..7b6043e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -797,7 +797,8 @@ void trace_find_cmdline(int pid, char comm[])
 
 void tracing_record_cmdline(struct task_struct *tsk)
 {
-	if (atomic_read(&trace_record_cmdline_disabled) || !tracing_is_on())
+	if (atomic_read(&trace_record_cmdline_disabled) || !tracer_enabled ||
+	    !tracing_is_on())
 		return;
 
 	trace_save_cmdline(tsk);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/