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.

Acked-by: Jeff Moyer <jmoyer@redhat.com>
CC: Christoph Hellwig <hch@infradead.org>
CC: Jens Axboe <axboe@kernel.dk>
CC: 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/direct-io.c b/fs/direct-io.c
index f4aadd15b61376ee97a4a7bababe2eb659850820..29c4fdab29db905af3340761d3d50df61e636209 100644 (file)
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -305,9 +305,9 @@ 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;