Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752144AbcDIFd2 (ORCPT ); Sat, 9 Apr 2016 01:33:28 -0400 Received: from mail-yw0-f171.google.com ([209.85.161.171]:35882 "EHLO mail-yw0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750899AbcDIFd0 (ORCPT ); Sat, 9 Apr 2016 01:33:26 -0400 MIME-Version: 1.0 In-Reply-To: <570892F9.9030700@lwfinger.net> References: <570892F9.9030700@lwfinger.net> Date: Fri, 8 Apr 2016 22:33:25 -0700 Message-ID: Subject: Re: Kernel crash on startup - bisected to commit 3b24d854cb35 From: Eric Dumazet To: Larry Finger Cc: "David S. Miller" , linux-next , linux-netdev@vger.kernel.org, LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1708 Lines: 38 On Fri, Apr 8, 2016 at 10:28 PM, Larry Finger wrote: > Following a recent pull of the wireless-drivers-next repo. my system got a > kernel panic on startup at native_apic_msr_write+0x27. The problem was > bisected to commit 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt > under synflood"). I am confident of the bisection as a kernel built with the > previous commit (3a5d1c0) boots OK. > > I have not yet captured the entire traceback for the crash, but I do have a > crappy photo of the screen that I have attached. The RIP is at > native_apic_msr_write+0x27. As this crash is likely configuration dependent, > a copy of my .config is also attached. Note that IPv6 is turned off on my > machine. > > Please let me know if any other info is needed. Can you double check you have this fix ? commit 8501786929de4616b10b8059ad97abd304a7dddf Author: Eric Dumazet Date: Wed Apr 6 22:07:34 2016 -0700 tcp/dccp: fix inet_reuseport_add_sock() David Ahern reported panics in __inet_hash() caused by my recent commit. The reason is inet_reuseport_add_sock() was still using sk_nulls_for_each_rcu() instead of sk_for_each_rcu(). SO_REUSEPORT enabled listeners were causing an instant crash. While chasing this bug, I found that I forgot to clear SOCK_RCU_FREE flag, as it is inherited from the parent at clone time. Fixes: 3b24d854cb35 ("tcp/dccp: do not touch listener sk_refcnt under synflood") Signed-off-by: Eric Dumazet Reported-by: David Ahern Tested-by: David Ahern Signed-off-by: David S. Miller