ext4: fix ext4_end_io_dio() racing against fsync()
We need to make sure iocb->private is cleared *before* we put the
io_end structure on i_completed_io_list. Otherwise fsync() could
potentially run on another CPU and free the iocb structure out from
under us.
Reported-by: Kent Overstreet <koverstreet@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@kernel.org
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 848f436..d2c8663 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2781,10 +2781,11 @@
iocb->private, io_end->inode->i_ino, iocb, offset,
size);
+ iocb->private = NULL;
+
/* if not aio dio with unwritten extents, just free io and return */
if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
ext4_free_io_end(io_end);
- iocb->private = NULL;
out:
if (is_async)
aio_complete(iocb, ret, 0);
@@ -2807,7 +2808,6 @@
spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
/* queue the work to convert unwritten extents to written */
- iocb->private = NULL;
queue_work(wq, &io_end->work);
/* XXX: probably should move into the real I/O completion handler */
