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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 <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This commit is contained in:
Steven Rostedt 2009-03-12 11:33:20 -04:00
parent a123c52b46
commit 1027fcb206
1 changed files with 4 additions and 1 deletions
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5
kernel/trace/trace.c
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@ -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;