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[PATCH 2/4] xfs: Fix possible use-after-free with AIO

To: linux-fsdevel@xxxxxxxxxxxxxxx
Subject: [PATCH 2/4] xfs: Fix possible use-after-free with AIO
From: Jan Kara <jack@xxxxxxx>
Date: Wed, 23 Jan 2013 13:56:18 +0100
Cc: tytso@xxxxxxx, bpm@xxxxxxx, jlbec@xxxxxxxxxxxx, Jan Kara <jack@xxxxxxx>, xfs@xxxxxxxxxxx, stable@xxxxxxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1358945780-23661-1-git-send-email-jack@xxxxxxx>
References: <1358945780-23661-1-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: xfs@xxxxxxxxxxx
CC: Ben Myers <bpm@xxxxxxx>
CC: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 fs/xfs/xfs_aops.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 4111a40..5f707e5 100644
--- 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);
-- 
1.7.1

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