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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2015-05-27 10:48:56 -0400
committerSteven Rostedt <rostedt@goodmis.org>2015-05-27 10:48:56 -0400
commit985e871b28fc3e73ccd21cb999ce61266dc8c941 (patch)
treed0b67209c5b3e8f0854994bce2aa6a40e9d3ce28 /kernel/trace
parent6776221bfe50afdc053527055577012a1acaabd5 (diff)
ring-buffer: Add trace_recursive checks to ring_buffer_write()
The ring_buffer_write() function isn't protected by the trace recursive writes. Luckily, this function is not used as much and is unlikely to ever recurse. But it should still have the protection, because even a call to ring_buffer_lock_reserve() could cause ring buffer corruption if called when ring_buffer_write() is being used. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ring_buffer.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1c037ad923db..6d6ebcea3463 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -3013,9 +3013,12 @@ int ring_buffer_write(struct ring_buffer *buffer,
if (length > BUF_MAX_DATA_SIZE)
goto out;
+ if (unlikely(trace_recursive_lock(cpu_buffer)))
+ goto out;
+
event = rb_reserve_next_event(buffer, cpu_buffer, length);
if (!event)
- goto out;
+ goto out_unlock;
body = rb_event_data(event);
@@ -3026,6 +3029,10 @@ int ring_buffer_write(struct ring_buffer *buffer,
rb_wakeups(buffer, cpu_buffer);
ret = 0;
+
+ out_unlock:
+ trace_recursive_unlock(cpu_buffer);
+
out:
preempt_enable_notrace();