From 985e871b28fc3e73ccd21cb999ce61266dc8c941 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 27 May 2015 10:48:56 -0400 Subject: [PATCH] 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 --- kernel/trace/ring_buffer.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) 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();