From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH 0/7] IPv4/IPv6 unregistration deadlock fixes Date: Wed, 13 May 2009 19:53:40 -0700 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: , Herbert Xu , Stephen Hemminger , Ben Greear , Patrick McHardy To: David Miller Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]:51478 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759948AbZENCxq (ORCPT ); Wed, 13 May 2009 22:53:46 -0400 Sender: netdev-owner@vger.kernel.org List-ID: A while ago it was noticed that unregistering network devices could cause deadlocks if virtual files that take the rtnl_lock were accessed at the wrong time. After looking at the different possibilities the only way to solve it cleanly without some kind of busy loop appears to be reducing the scope of the rtnl lock. I have not tackled the hard fix yet but I have tested our current work around and it does not succeed in restarting the system call and instead leaks -ERESTARNOSYS to userspace, because we do not have a signal pending. Further the current work around misses several interesting places in the network stack where the deadlock can occur. I have addressed the problems by making a common helper function and patching all of the places I could find that had this problem. Eric