From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zdenek Kabelac Subject: Re: System freeze on reboot - general protection fault Date: Thu, 3 Sep 2009 00:31:07 +0200 Message-ID: References: <4A87CE60.4020506@gmail.com> <4A896324.3040104@trash.net> <4A9EEF07.5070800@gmail.com> 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: Eric Dumazet Return-path: In-Reply-To: <4A9EEF07.5070800@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 2009/9/3 Eric Dumazet : > Zdenek Kabelac a =E9crit : >> 2009/8/17 Patrick McHardy : >>> Eric Dumazet wrote: >>>> Zdenek Kabelac a =E9crit : >>>>> =A0[] nf_conntrack_ftp_fini+0x2f/0x70 [nf_connt= rack_ftp] >>>>> =A0[] sys_delete_module+0x1a5/0x270 >>>>> =A0[] ? retint_swapgs+0xe/0x13 >>>>> =A0[] ? trace_hardirqs_on_caller+0x162/0x1b0 >>>>> =A0[] ? audit_syscall_entry+0x191/0x1c0 >>>>> =A0[] ? trace_hardirqs_on_thunk+0x3a/0x3f >>>>> =A0[] 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 =A0[] nf_conntrack_helper_unregister+0x16c/= 0x320 >>>>> [nf_conntrack] >>>>> =A0RSP >>>>> CR2: 0000000000000038 >>>>> ---[ end trace bc3a0ede3d0084db ]--- >>>>> >>>> I am currently traveling and wont be able to help you before next = week. >>>> >>>> I added netdev, Patrick, and netfilter-devel in CC so that more ey= es 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. >>> >> >> Ok >> >> I've found the solution for my problem. >> >> http://thread.gmane.org/gmane.comp.security.firewalls.netfilter.deve= l/30483 >> >> I've made this small fix from this thread: >> >> diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_co= nntrack_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= ) >> =A0{ >> =A0 =A0 =A0 =A0 nf_conntrack_helper_fini(); >> =A0 =A0 =A0 =A0 nf_conntrack_proto_fini(); >> + =A0 =A0 =A0 rcu_barrier(); >> =A0 =A0 =A0 =A0 kmem_cache_destroy(nf_conntrack_cachep); >> =A0} >> >> @@ -1266,7 +1267,7 @@ static int nf_conntrack_init_init_net(void) >> >> =A0 =A0 =A0 =A0 nf_conntrack_cachep =3D kmem_cache_create("nf_conntr= ack", >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0 =A0 sizeof(struct nf_conn), >> - =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0 0, SLAB_DESTROY_BY_RCU, NULL); >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 =A0 =A0 =A0 0, 0, NULL); >> =A0 =A0 =A0 =A0 if (!nf_conntrack_cachep) { >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 printk(KERN_ERR "Unable to create nf= _conn slab cache\n"); >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 ret =3D -ENOMEM; >> >> >> As the thread nf_conntrack: Use rcu_barrier() and fix kmem_cache_cre= ate flags >> seems to be samewhat 'unfinished' =A0and already a bit old and I've = no >> idea whether it actually fixes problem completely or just hides it i= n >> my case - I'm leaving it to some RCU gurus to fix this issue. >> >> All I could say is - this this extra rcu_barrier() and removal of >> SLAB_DESTROY removes my GPF on reboot. >> >> 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 = good reasons. > Well I'm not noticing any ill behavior - also note - rcu_barrier() is there before the cache is destroyed. But as I said - it's just my shot into the dark - which seems to work f= or me... Zdenek