Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932315AbaFLDqh (ORCPT ); Wed, 11 Jun 2014 23:46:37 -0400 Received: from kirsty.vergenet.net ([202.4.237.240]:50772 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932150AbaFLDqg (ORCPT ); Wed, 11 Jun 2014 23:46:36 -0400 Date: Thu, 12 Jun 2014 12:46:33 +0900 From: Simon Horman To: Jet Chen Cc: Julian Anastasov , Wensong Zhang , Fengguang Wu , Linux Kernel Mailing List Subject: Re: [net/ipvs] BUG: unable to handle kernel NULL pointer dereference at 00000004 Message-ID: <20140612034633.GH22273@verge.net.au> References: <5397DE0E.2070501@intel.com> <5398148B.603@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5398148B.603@intel.com> Organisation: Horms Solutions Ltd. User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 11, 2014 at 04:34:19PM +0800, Jet Chen wrote: > 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 Thanks, Julian, should I take this one? I'm assuming this problem has been present for quite a number of releases. > > 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/