tracing: Add checks if tr->buffer is NULL in tracing_reset{_online_cpus}

max_tr->buffer could be NULL in the tracing_reset{_online_cpus}. In this
case, a NULL pointer dereference happens, so we should return immediately
from these functions.

Note, the current code does not call tracing_reset*() with max_tr when
its buffer is NULL, but future code will. This patch is needed to prevent
the future code from crashing.

Link: http://lkml.kernel.org/r/20121219070234.31200.93863.stgit@liselsia

Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Hiraku Toyooka 2012-12-19 16:02:34 +09:00 committed by Steven Rostedt
parent 6aea49cb5f
commit a54164114b

View File

@ -922,6 +922,9 @@ void tracing_reset(struct trace_array *tr, int cpu)
{
struct ring_buffer *buffer = tr->buffer;
if (!buffer)
return;
ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */
@ -936,6 +939,9 @@ void tracing_reset_online_cpus(struct trace_array *tr)
struct ring_buffer *buffer = tr->buffer;
int cpu;
if (!buffer)
return;
ring_buffer_record_disable(buffer);
/* Make sure all commits have finished */