From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: System freeze on reboot - general protection fault Date: Thu, 03 Sep 2009 00:17:43 +0200 Message-ID: <4A9EEF07.5070800@gmail.com> References: <20090811154853.GF2763@sgi.com> <4A87CE60.4020506@gmail.com> <4A896324.3040104@trash.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Patrick McHardy , Christoph Lameter , Robin Holt , Linux Kernel Mailing List , Pekka Enberg , Jesper Dangaard Brouer , Linux Netdev List , Netfilter Developers To: Zdenek Kabelac Return-path: Received: from gw1.cosmosbay.com ([212.99.114.194]:42276 "EHLO gw1.cosmosbay.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753610AbZIBWSj (ORCPT ); Wed, 2 Sep 2009 18:18:39 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Zdenek Kabelac a =E9crit : > 2009/8/17 Patrick McHardy : >> Eric Dumazet wrote: >>> Zdenek Kabelac a =E9crit : >>>> [] nf_conntrack_ftp_fini+0x2f/0x70 [nf_conntrac= k_ftp] >>>> [] sys_delete_module+0x1a5/0x270 >>>> [] ? retint_swapgs+0xe/0x13 >>>> [] ? trace_hardirqs_on_caller+0x162/0x1b0 >>>> [] ? audit_syscall_entry+0x191/0x1c0 >>>> [] ? trace_hardirqs_on_thunk+0x3a/0x3f >>>> [] system_call_fastpath+0x16/0x1b >>>> Code: c6 00 00 0f 82 66 ff ff ff 49 8b 9e d8 05 00 00 48 85 db 75 = 16 >>>> e9 8e 00 00 00 0f 1f 44 00 00 48 85 c0 0f 84 80 00 00 00 48 89 c3 = <0f> >>>> b6 4b 37 48 8b 03 48 8d 14 cd 00 00 00 00 0f 18 08 48 29 ca >>>> RIP [] nf_conntrack_helper_unregister+0x16c/0x3= 20 >>>> [nf_conntrack] >>>> RSP >>>> CR2: 0000000000000038 >>>> ---[ end trace bc3a0ede3d0084db ]--- >>>> >>> I am currently traveling and wont be able to help you before next w= eek. >>> >>> I added netdev, Patrick, and netfilter-devel in CC so that more eye= s can take a look. >> Thanks for the report, I'll have a look at this. Zdenek, please >> send me the nf_conntrack.ko file used in the above oops. Thanks. >> >=20 > Ok >=20 > I've found the solution for my problem. >=20 > http://thread.gmane.org/gmane.comp.security.firewalls.netfilter.devel= /30483 >=20 > I've made this small fix from this thread: >=20 > diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_con= ntrack_core > index b5869b9..68488f8 100644 > --- a/net/netfilter/nf_conntrack_core.c > +++ b/net/netfilter/nf_conntrack_core.c > @@ -1108,6 +1108,7 @@ static void nf_conntrack_cleanup_init_net(void) > { > nf_conntrack_helper_fini(); > nf_conntrack_proto_fini(); > + rcu_barrier(); > kmem_cache_destroy(nf_conntrack_cachep); > } >=20 > @@ -1266,7 +1267,7 @@ static int nf_conntrack_init_init_net(void) >=20 > nf_conntrack_cachep =3D kmem_cache_create("nf_conntrack", > sizeof(struct nf_conn= ), > - 0, SLAB_DESTROY_BY_RC= U, NULL); > + 0, 0, NULL); > if (!nf_conntrack_cachep) { > printk(KERN_ERR "Unable to create nf_conn slab cache\= n"); > ret =3D -ENOMEM; >=20 >=20 > As the thread nf_conntrack: Use rcu_barrier() and fix kmem_cache_crea= te flags > seems to be samewhat 'unfinished' and already a bit old and I've no > idea whether it actually fixes problem completely or just hides it in > my case - I'm leaving it to some RCU gurus to fix this issue. >=20 > All I could say is - this this extra rcu_barrier() and removal of > SLAB_DESTROY removes my GPF on reboot. >=20 > Zdenek Ouch.. Dont think such a patch makes your kernel better, it'll crash too. You cannot remove SLAB_DESTROY_BY_RCU like this, it's there for very go= od reasons.