Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751505AbaFKIe0 (ORCPT ); Wed, 11 Jun 2014 04:34:26 -0400 Received: from mga11.intel.com ([192.55.52.93]:47968 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751003AbaFKIeY (ORCPT ); Wed, 11 Jun 2014 04:34:24 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,456,1400050800"; d="scan'208";a="553703804" Message-ID: <5398148B.603@intel.com> Date: Wed, 11 Jun 2014 16:34:19 +0800 From: Jet Chen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Julian Anastasov CC: Wensong Zhang , Simon Horman , Fengguang Wu , Linux Kernel Mailing List Subject: Re: [net/ipvs] BUG: unable to handle kernel NULL pointer dereference at 00000004 References: <5397DE0E.2070501@intel.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/11/2014 01:59 PM, Julian Anastasov wrote: > > Hello, > > On Wed, 11 Jun 2014, Jet Chen wrote: > >> Hi Wensong, >> >> 0day kernel testing robot got the below dmesg. >> >> +-------------------------------------------------------+----+ >> | boot_successes | 26 | >> | boot_failures | 4 | >> | BUG:unable_to_handle_kernel_NULL_pointer_dereference | 4 | >> | Oops | 4 | >> | EIP_is_at_ip_vs_stop_estimator | 4 | >> | Kernel_panic-not_syncing:Fatal_exception_in_interrupt | 4 | >> | backtrace:cleanup_net | 4 | >> +-------------------------------------------------------+----+ >> >> >> [child0:2725] process_vm_readv (347) returned ENOSYS, marking as inactive. >> [child0:2725] uid changed! Was: 0, now -788547075 >> Bailing main loop. Exit reason: UID changed. >> [ 12.182233] BUG: unable to handle kernel NULL pointer dereference at 00000004 >> [ 12.183011] IP: [<4c2f6567>] ip_vs_stop_estimator+0x20/0x3e >> [ 12.183011] *pdpt = 0000000000000000 *pde = f000ff53f000ff53 [ 12.183011] Oops: 0002 [#1] DEBUG_PAGEALLOC >> [ 12.183011] Modules linked in: >> [ 12.183011] CPU: 0 PID: 57 Comm: kworker/u2:1 Not tainted 3.15.0-rc8 #1 >> [ 12.183011] Workqueue: netns cleanup_net >> [ 12.183011] task: 528773f0 ti: 52878000 task.ti: 52878000 >> [ 12.183011] EIP: 0060:[<4c2f6567>] EFLAGS: 00010206 CPU: 0 >> [ 12.183011] EIP is at ip_vs_stop_estimator+0x20/0x3e >> [ 12.183011] EAX: 00000000 EBX: 51c39a54 ECX: 00000000 EDX: 00000000 > > ip_vs_stop_estimator fails at list_del(&est->list) > on mov %eax,0x4(%edx) instruction and EDX is 0. It means, > this estimator was never started (initialized with > INIT_LIST_HEAD in ip_vs_start_estimator) or stopped > before with the same list_del. > > At first look, it is strange but I think the reason > is the missing CONFIG_SYSCTL. ip_vs_control_net_cleanup > fails at ip_vs_stop_estimator(net, &ipvs->tot_stats) > because it is called not depending on CONFIG_SYSCTL but > without CONFIG_SYSCTL ip_vs_start_estimator was never > called. > > Can you test such patch? Julian, your patch works. Thanks. Tested-by: Jet Chen > > ipvs: stop tot_stats estimator only under CONFIG_SYSCTL > > The tot_stats estimator is started only when CONFIG_SYSCTL > is defined. But it is stopped without checking CONFIG_SYSCTL. > Fix the crash by moving ip_vs_stop_estimator into > ip_vs_control_net_cleanup_sysctl. > > Signed-off-by: Julian Anastasov > --- > net/netfilter/ipvs/ip_vs_ctl.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c > index c42e83d..581a658 100644 > --- a/net/netfilter/ipvs/ip_vs_ctl.c > +++ b/net/netfilter/ipvs/ip_vs_ctl.c > @@ -3778,6 +3778,7 @@ static void __net_exit ip_vs_control_net_cleanup_sysctl(struct net *net) > cancel_delayed_work_sync(&ipvs->defense_work); > cancel_work_sync(&ipvs->defense_work.work); > unregister_net_sysctl_table(ipvs->sysctl_hdr); > + ip_vs_stop_estimator(net, &ipvs->tot_stats); > } > > #else > @@ -3840,7 +3841,6 @@ void __net_exit ip_vs_control_net_cleanup(struct net *net) > struct netns_ipvs *ipvs = net_ipvs(net); > > ip_vs_trash_cleanup(net); > - ip_vs_stop_estimator(net, &ipvs->tot_stats); > ip_vs_control_net_cleanup_sysctl(net); > remove_proc_entry("ip_vs_stats_percpu", net->proc_net); > remove_proc_entry("ip_vs_stats", net->proc_net); > -- 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/