From a54164114b96b4693b42cdb553260eec41ea4393 Mon Sep 17 00:00:00 2001 From: Hiraku Toyooka Date: Wed, 19 Dec 2012 16:02:34 +0900 Subject: [PATCH] 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 Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f8b7c626f3fd..72b171b90e55 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -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 */