diff options
authorTejun Heo <>2011-11-24 19:22:24 -0500
committerGreg Kroah-Hartman <>2011-12-09 08:54:18 -0800
commit01da30a885baa667801facc2a54c80346ab6c414 (patch)
parent453fdf5561cc042b7e127af6a62138969726f539 (diff)
ext4: fix racy use-after-free in ext4_end_io_dio()
commit 4c81f045c0bd2cbb78cc6446a4cd98038fe11a2e upstream. ext4_end_io_dio() queues io_end->work and then clears iocb->private; however, io_end->work calls aio_complete() which frees the iocb object. If that slab object gets reallocated, then ext4_end_io_dio() can end up clearing someone else's iocb->private, this use-after-free can cause a leak of a struct ext4_io_end_t structure. Detected and tested with slab poisoning. [ Note: Can also reproduce using 12 fio's against 12 file systems with the following configuration file: [global] direct=1 ioengine=libaio iodepth=1 bs=4k ba=4k size=128m [create] filename=${TESTDIR} rw=write -- tytso ] Google-Bug-Id: 5354697 Signed-off-by: Tejun Heo <> Signed-off-by: "Theodore Ts'o" <> Reported-by: Kent Overstreet <> Tested-by: Kent Overstreet <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 89c47f4ee005..b644b9c164a7 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2656,8 +2656,8 @@ out:
spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
/* queue the work to convert unwritten extents to written */
- queue_work(wq, &io_end->work);
iocb->private = NULL;
+ queue_work(wq, &io_end->work);
/* XXX: probably should move into the real I/O completion handler */