From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: [PATCH] ext4: fix ext4_end_io_dio() racing against fsync() Date: Wed, 30 Nov 2011 15:53:48 -0500 Message-ID: <1322686428-17728-1-git-send-email-tytso@mit.edu> Cc: curtw@google.com, Theodore Ts'o To: Ext4 Developers List Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:53951 "EHLO test.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752483Ab1K3Uxz (ORCPT ); Wed, 30 Nov 2011 15:53:55 -0500 Sender: linux-ext4-owner@vger.kernel.org List-ID: 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 Signed-off-by: "Theodore Ts'o" --- fs/ext4/inode.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) 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 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset, 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 @@ 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 */ -- 1.7.4.1.22.gec8e1.dirty