From: Jan Kara <jack@suse.cz>
Date: Tue, 29 Jan 2013 23:28:01 +0000 (+0100)
Subject: fs: Fix possible use-after-free with AIO
X-Git-Tag: v3.2.40~59
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=53edcd239765c93597d079ac98858916d1f724f4;p=thirdparty%2Fkernel%2Fstable.git

fs: Fix possible use-after-free with AIO

commit 54c807e71d5ac59dee56c685f2b66e27cd54c475 upstream.

Running AIO is pinning inode in memory using file reference. Once AIO
is completed using aio_complete(), file reference is put and inode can
be freed from memory. So we have to be sure that calling aio_complete()
is the last thing we do with the inode.

CC: Christoph Hellwig <hch@infradead.org>
CC: Jens Axboe <axboe@kernel.dk>
CC: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/fs/direct-io.c b/fs/direct-io.c
index d740ab67ff6e1..ac401d229f9be 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -304,9 +304,9 @@ static ssize_t dio_complete(struct dio *dio, loff_t offset, ssize_t ret, bool is
 		dio->end_io(dio->iocb, offset, transferred,
 			    dio->private, ret, is_async);
 	} else {
+		inode_dio_done(dio->inode);
 		if (is_async)
 			aio_complete(dio->iocb, ret, 0);
-		inode_dio_done(dio->inode);
 	}
 
 	return ret;