Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756394AbbHZLuH (ORCPT ); Wed, 26 Aug 2015 07:50:07 -0400 Received: from mail-ig0-f174.google.com ([209.85.213.174]:37142 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751859AbbHZLuE convert rfc822-to-8bit (ORCPT ); Wed, 26 Aug 2015 07:50:04 -0400 Date: Wed, 26 Aug 2015 07:49:59 -0400 From: Chuck Ebbert To: Shaun Crampton Cc: linux-kernel@vger.kernel.org, Peter White , netdev@vger.kernel.org Subject: Re: ip_rcv_finish() NULL pointer and possibly related Oopses Message-ID: <20150826074959.48aea34c@as> In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6103 Lines: 116 On Wed, 26 Aug 2015 08:46:59 +0000 Shaun Crampton wrote: > Testing our app at scale on Google¹s GCE, running ~1000 CoreOS hosts: over > approximately 1 hour, I see about 1 in 50 hosts hit one of the Oopses > below and then reboot (I¹m not sure if the different oopses are related to > each other). > > The app is Project Calico, which is a datacenter networking fabric. > calico-felix, the process named below, is our per-host agent. The > per-host agent is responsible for reading the network information from a > central server and applying "ip route² and "iptables" updates to the > kernel. We¹re running on CoreOS, with about 100 docker containers/veths > pairs running on each host. calico-felix is running inside one of those > containers. We also run the BIRD BGP stack to redistribute routes around > the datacenter. The errors happen more frequently while Calico is under > load. > > I¹m not sure where to go from here. I can reproduce these issues easily > at that scale but I haven¹t managed to boil it down to a small-scale repro > scenario for further investigation (yet). > What in the world is going on with those call traces? E.g.: > [ 4513.712008] > [ 4513.712008] [] ? ip_rcv_finish+0x81/0x360 > [ 4513.712008] [] ip_rcv+0x2a4/0x400 > [ 4513.712008] [] ? inet_del_offload+0x40/0x40 > [ 4513.712008] [] __netif_receive_skb_core+0x6c3/0x9a0 > [ 4513.712008] [] ? build_skb+0x17/0x90 > [ 4513.712008] [] __netif_receive_skb+0x18/0x60 > [ 4513.712008] [] netif_receive_skb_internal+0x33/0xa0 > [ 4513.712008] [] netif_receive_skb_sk+0x1c/0x70 > [ 4513.712008] [] 0xffffffffa00f772b > [ 4513.712008] [] ? __netif_receive_skb_core+0x6c3/0x9a0 > [ 4513.712008] [] 0xffffffffa00f7d81 > [ 4513.712008] [] net_rx_action+0x159/0x340 > [ 4513.712008] [] __do_softirq+0xf4/0x290 > [ 4513.712008] [] irq_exit+0xad/0xc0 > [ 4513.712008] [] do_IRQ+0x5a/0xf0 > [ 4513.712008] [] common_interrupt+0x6e/0x6e > [ 4513.712008] There are two functions in the call trace that the kernel knows nothing about. How did they get in there? And there is really executable code in there, as can be seen from a later trace: > [ 4123.003006] > [ 4123.003006] [] nf_iterate+0x57/0x80 > [ 4123.003006] [] nf_hook_slow+0x97/0x100 > [ 4123.003006] [] ip_local_deliver+0x92/0xa0 > [ 4123.003006] [] ? ip_rcv_finish+0x360/0x360 > [ 4123.003006] [] ip_rcv_finish+0x81/0x360 > [ 4123.003006] [] ip_rcv+0x2a4/0x400 > [ 4123.003006] [] ? inet_del_offload+0x40/0x40 > [ 4123.003006] [] __netif_receive_skb_core+0x6c3/0x9a0 > [ 4123.003006] [] ? build_skb+0x17/0x90 > [ 4123.003006] [] __netif_receive_skb+0x18/0x60 > [ 4123.003006] [] netif_receive_skb_internal+0x33/0xa0 > [ 4123.003006] [] netif_receive_skb_sk+0x1c/0x70 > [ 4123.003006] [] 0xffffffffa00d472b > [ 4123.003006] [] 0xffffffffa00d4d81 > [ 4123.003006] [] net_rx_action+0x159/0x340 > [ 4123.003006] [] __do_softirq+0xf4/0x290 > [ 4123.003006] [] irq_exit+0xad/0xc0 > [ 4123.003006] [] do_IRQ+0x5a/0xf0 > [ 4123.003006] [] common_interrupt+0x6e/0x6e > [ 4123.003006] > [ 4123.003006] [] ? __ip_route_output_key+0x31d/0x860 > [ 4123.003006] [] ? xfrm_lookup_route+0x5/0x70 > [ 4123.003006] [] ? ip_route_output_flow+0x54/0x60 > [ 4123.003006] [] ip_queue_xmit+0x36a/0x3d0 > [ 4123.003006] [] tcp_transmit_skb+0x4b9/0x990 > [ 4123.003006] [] tcp_write_xmit+0x115/0xe90 > [ 4123.003006] [] __tcp_push_pending_frames+0x32/0xd0 > [ 4123.003006] [] tcp_push+0xef/0x120 > [ 4123.003006] [] tcp_sendmsg+0xc5/0xb20 > [ 4123.003006] [] ? lock_hrtimer_base.isra.22+0x29/0x50 > [ 4123.003006] [] inet_sendmsg+0x64/0xa0 > [ 4123.003006] [] ? __fget_light+0x25/0x70 > [ 4123.003006] [] sock_sendmsg+0x3d/0x50 > [ 4123.003006] [] SYSC_sendto+0x102/0x1a0 > [ 4123.003006] [] ? __audit_syscall_entry+0xb4/0x110 > [ 4123.003006] [] ? do_audit_syscall_entry+0x6c/0x70 > [ 4123.003006] [] ? > syscall_trace_enter_phase1+0x103/0x160 > [ 4123.003006] [] SyS_sendto+0xe/0x10 > [ 4123.003006] [] system_call_fastpath+0x12/0x71 > [ 4123.003006] Code: <48> 8b 88 40 03 00 00 e8 1d dd dd ff 5d c3 0f 1f 00 > 41 83 b9 80 00 > [ 4123.003006] RIP [] 0xffffffffa0233027 > [ 4123.003006] RSP Presumably the same two functions as before (loaded at a different base address but same offsets, 0xd81 and 0x72b). And then nf_iterate call into another unknown function, and there really is code there and it's consistent with the oops. And the kernel thinks it's outside of any normal text section, so it does not try to dump any code from before the instruction pointer. 0: 48 8b 88 40 03 00 00 mov 0x340(%rax),%rcx 7: e8 1d dd dd ff callq 0xffffffffffdddd29 c: 5d pop %rbp d: c3 retq Did you write your own module loader or something? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/