From: Jens Axboe <axboe@kernel.dk>
Date: Sun, 19 Nov 2017 18:52:55 +0000 (-0700)
Subject: blktrace: fix trace mutex deadlock
X-Git-Tag: v4.9.224~60
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0f62edba7ca63ba8abd05379b812723162313608;p=platform%2Fkernel%2Flinux-amlogic.git

blktrace: fix trace mutex deadlock

commit 2967acbb257a6a9bf912f4778b727e00972eac9b upstream.

A previous commit changed the locking around registration/cleanup,
but direct callers of blk_trace_remove() were missed. This means
that if we hit the error path in setup, we will deadlock on
attempting to re-acquire the queue trace mutex.

Fixes: 1f2cac107c59 ("blktrace: fix unlocked access to init/start-stop/teardown")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 55337d797deb..a88e677c74f3 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -572,7 +572,7 @@ static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 		return ret;
 
 	if (copy_to_user(arg, &buts, sizeof(buts))) {
-		blk_trace_remove(q);
+		__blk_trace_remove(q);
 		return -EFAULT;
 	}
 	return 0;
@@ -618,7 +618,7 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
 		return ret;
 
 	if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
-		blk_trace_remove(q);
+		__blk_trace_remove(q);
 		return -EFAULT;
 	}