From 1027fcb206a0fb8348e63aff078c74bdee1c2698 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 12 Mar 2009 11:33:20 -0400 Subject: [PATCH] tracing: protect ring_buffer_expanded with trace_types_lock Impact: prevent races with ring_buffer_expanded This patch places the expanding of the tracing buffer under the protection of the trace_types_lock mutex. It is highly unlikely that there would be any contention, but better safe than sorry. Reported-by: Andrew Morton Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index c61ee85c50bb..04ab8243a13d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2391,8 +2391,10 @@ int tracing_update_buffers(void) { int ret = 0; + mutex_lock(&trace_types_lock); if (!ring_buffer_expanded) ret = tracing_resize_ring_buffer(trace_buf_size); + mutex_unlock(&trace_types_lock); return ret; } @@ -2412,6 +2414,8 @@ static int tracing_set_tracer(const char *buf) struct tracer *t; int ret = 0; + mutex_lock(&trace_types_lock); + if (!ring_buffer_expanded) { ret = tracing_resize_ring_buffer(trace_buf_size); if (ret < 0) @@ -2419,7 +2423,6 @@ static int tracing_set_tracer(const char *buf) ret = 0; } - mutex_lock(&trace_types_lock); for (t = trace_types; t; t = t->next) { if (strcmp(t->name, buf) == 0) break; -- 2.34.1