Messages in this thread Patch in this message | | | Date | Fri, 16 Dec 2011 11:45:38 -0800 | From | Greg KH <> | Subject | [41/53] ext4: fix ext4_end_io_dio() racing against fsync() |
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3.1-stable review patch. If anyone has any objections, please let me know.
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From: Theodore Ts'o <tytso@mit.edu>
commit b5a7e97039a80fae673ccc115ce595d5b88fb4ee upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/ext4/inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2630,10 +2630,11 @@ static void ext4_end_io_dio(struct kiocb 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); @@ -2656,7 +2657,6 @@ out: 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 */
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