[PATCH 115/139] fs: Fix possible use-after-free with AIO

From: Luis Henriques
Date: Thu Feb 28 2013 - 09:57:53 EST -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.

CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
CC: Jens Axboe <axboe@xxxxxxxxx>
CC: Jeff Moyer <jmoyer@xxxxxxxxxx>
Acked-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
fs/direct-io.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 0c85fae..84466cb 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;

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