[ 3.5.y.z extended stable ] Patch "fs: Fix possible use-after-free with AIO" has been added to staging queue

Luis Henriques luis.henriques at canonical.com
Thu Feb 28 11:58:50 UTC 2013


This is a note to let you know that I have just added a patch titled

    fs: Fix possible use-after-free with AIO

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 354fcd5599fdcf83c2dc54b5e9eb7dd8b817b317 Mon Sep 17 00:00:00 2001
From: Jan Kara <jack at suse.cz>
Date: Wed, 30 Jan 2013 00:28:01 +0100
Subject: [PATCH] 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.

CC: Christoph Hellwig <hch at infradead.org>
CC: Jens Axboe <axboe at kernel.dk>
CC: Jeff Moyer <jmoyer at redhat.com>
Acked-by: Jeff Moyer <jmoyer at redhat.com>
Signed-off-by: Jan Kara <jack at suse.cz>
Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 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;
--
1.8.1.2





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