xfs: Fix possible use-after-free with AIO

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: xfs@oss.sgi.com
CC: Ben Myers <bpm@sgi.com>
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 4111a40ebe1a17dde31f89e5154c0d257c6e5d6c..5f707e5371717a331131f72f5babff24670d9bef 100644 (file)
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -86,11 +86,11 @@ xfs_destroy_ioend(
        }
 
        if (ioend->io_iocb) {
+               inode_dio_done(ioend->io_inode);
                if (ioend->io_isasync) {
                        aio_complete(ioend->io_iocb, ioend->io_error ?
                                        ioend->io_error : ioend->io_result, 0);
                }
-               inode_dio_done(ioend->io_inode);
        }
 
        mempool_free(ioend, xfs_ioend_pool);