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[PATCH 4/4] fs: Fix possible use-after-free with AIO

To: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Subject: [PATCH 4/4] fs: Fix possible use-after-free with AIO
From: Jan Kara <jack@xxxxxxx>
Date: Wed, 30 Jan 2013 00:28:01 +0100
Cc: linux-fsdevel@xxxxxxxxxxxxxxx, xfs@xxxxxxxxxxx, linux-ext4@xxxxxxxxxxxxxxx, ocfs2-devel@xxxxxxxxxxxxxx, Jan Kara <jack@xxxxxxx>, Christoph Hellwig <hch@xxxxxxxxxxxxx>, Jens Axboe <axboe@xxxxxxxxx>, Jeff Moyer <jmoyer@xxxxxxxxxx>, stable@xxxxxxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1359502081-20240-1-git-send-email-jack@xxxxxxx>
References: <1359502081-20240-1-git-send-email-jack@xxxxxxx>
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@xxxxxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
CC: Jeff Moyer <jmoyer@xxxxxxxxxx>
CC: stable@xxxxxxxxxxxxxxx
Acked-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 fs/direct-io.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index cf5b44b..f853263 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -261,9 +261,9 @@ 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;
-- 
1.7.1

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