[ 42/77] fs: Fix possible use-after-free with AIO

From: Greg Kroah-Hartman
Date: Fri Mar 01 2013 - 15:14:38 EST


3.8-stable review patch. If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@xxxxxxx>

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@xxxxxxxxxx>
CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
CC: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
fs/direct-io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -261,9 +261,9 @@ static ssize_t dio_complete(struct dio *
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;


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