From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: [PATCH 1/3] netns: Fix icmp shutdown. Date: Fri, 20 Feb 2009 07:52:36 -0800 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: In-Reply-To: (Eric W. Biederman's message of "Fri\, 20 Feb 2009 07\:47\:01 -0800") Sender: netdev-owner@vger.kernel.org To: David Miller Cc: Linux Containers , netdev@vger.kernel.org, Alexey Dobriyan , "Denis V. Lunev" List-Id: containers.vger.kernel.org Recently I had a kernel panic in icmp_send during a network namespace cleanup. There were packets in the arp queue that failed to be sent and we attempted to generate an ICMP host unreachable message, but failed because icmp_sk_exit had already been called. The network devices are removed from a network namespace and their arp queues are flushed before we do attempt to shutdown subsystems so this error should have been impossible. It turns out icmp_init is using register_pernet_device instead of register_pernet_subsys. Which resulted in icmp being shut down while we still had the possibility of packets in flight, making a nasty NULL pointer deference in interrupt context possible. Changing this to register_pernet_subsys fixes the problem in my testing. Signed-off-by: Eric W. Biederman --- net/ipv4/icmp.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c index 382800a..3f50807 100644 --- a/net/ipv4/icmp.c +++ b/net/ipv4/icmp.c @@ -1207,7 +1207,7 @@ static struct pernet_operations __net_initdata icmp_sk_ops = { int __init icmp_init(void) { - return register_pernet_device(&icmp_sk_ops); + return register_pernet_subsys(&icmp_sk_ops); } EXPORT_SYMBOL(icmp_err_convert); -- 1.6.1.2.350.g88cc