| Message ID | 20120912213627.GJ14750@breakpoint.cc |
|---|---|
| State | Not Applicable |
| Headers | show |
On Wed, Sep 12, 2012 at 11:36:27PM +0200, Florian Westphal wrote: > Jesper Dangaard Brouer <brouer@redhat.com> wrote: > > [ CC'd Patrick ] > > > I'm hitting this general protection fault, when unloading iptables_nat. > > [ 524.591067] Pid: 5842, comm: modprobe Not tainted 3.6.0-rc3-pablo-nf-next+ #1 Red Hat KVM > > [ 524.591067] RIP: 0010:[<ffffffffa002c2fd>] [<ffffffffa002c2fd>] nf_nat_proto_clean+0x6d/0xc0 [nf_nat] > > [ 524.591067] RSP: 0018:ffff880073203e18 EFLAGS: 00010246 > > [ 524.591067] RAX: 0000000000000000 RBX: ffff880077dff2c8 RCX: ffff8800797fab70 > > [ 524.591067] RDX: dead000000200200 RSI: ffff880073203e88 RDI: ffffffffa002f208 > > [ 524.591067] RBP: ffff880073203e28 R08: ffff880073202000 R09: 0000000000000000 > > [ 524.591067] R10: dead000000200200 R11: dead000000100100 R12: ffffffff81c6dc00 > > list corruption? ^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^ > > Yep, looks like it. > > > [ 524.591067] [<ffffffffa002c290>] ? nf_nat_net_exit+0x50/0x50 [nf_nat] > > [ 524.591067] [<ffffffff815614e3>] nf_ct_iterate_cleanup+0xc3/0x170 > > [ 524.591067] [<ffffffffa002c54a>] nf_nat_l3proto_unregister+0x8a/0x100 [nf_nat] > > [ 524.591067] [<ffffffff812a0303>] ? compat_prepare_timeout+0x13/0xb0 > > [ 524.591067] [<ffffffffa0035848>] nf_nat_l3proto_ipv4_exit+0x10/0x23 [nf_nat_ipv4] > > On module removal nf_nat_ipv4 calls nf_iterate_cleanup which invokes > nf_nat_proto_clean() for each conntrack. That will then call > hlist_del_rcu(&nat->bysource) using eachs conntracks nat ext area. > > Problem is that nf_nat_proto_clean() is called multiple times for the same > conntrack: > a) nf_ct_iterate_cleanup() returns each ct twice (origin, reply) > b) we call it both for l3 and for l4 protocol ids > > We barf in hlist_del_rcu the 2nd time because ->pprev is poisoned. > > This was introduced with the ipv6 nat patches. > > --- a/net/netfilter/nf_nat_core.c > +++ b/net/netfilter/nf_nat_core.c > @@ -487,7 +487,7 @@ static int nf_nat_proto_clean(struct nf_conn *i, void *data) > > if (clean->hash) { > spin_lock_bh(&nf_nat_lock); > - hlist_del_rcu(&nat->bysource); > + hlist_del_init_rcu(&nat->bysource); > spin_unlock_bh(&nf_nat_lock); > } else { > > Would probably avoid it. I guess it would be nicer to only call this > once for each ct. > > Patrick, any other idea? I already discussed this with Florian (I've been having problems with two out of three of my email accounts this week... so I couldn't reply to this email in the mailing list). We can add nf_nat_iterate_cleanup that can iterate over the NAT hashtable to replace current usage of nf_ct_iterate_cleanup. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 2012-09-12 at 23:36 +0200, Florian Westphal wrote: [...cut...] > On module removal nf_nat_ipv4 calls nf_iterate_cleanup which invokes > nf_nat_proto_clean() for each conntrack. That will then call > hlist_del_rcu(&nat->bysource) using eachs conntracks nat ext area. > > Problem is that nf_nat_proto_clean() is called multiple times for the same > conntrack: > a) nf_ct_iterate_cleanup() returns each ct twice (origin, reply) > b) we call it both for l3 and for l4 protocol ids > > We barf in hlist_del_rcu the 2nd time because ->pprev is poisoned. > > This was introduced with the ipv6 nat patches. > > --- a/net/netfilter/nf_nat_core.c > +++ b/net/netfilter/nf_nat_core.c > @@ -487,7 +487,7 @@ static int nf_nat_proto_clean(struct nf_conn *i, void *data) > > if (clean->hash) { > spin_lock_bh(&nf_nat_lock); > - hlist_del_rcu(&nat->bysource); > + hlist_del_init_rcu(&nat->bysource); > spin_unlock_bh(&nf_nat_lock); > } else { > > Would probably avoid it. I guess it would be nicer to only call this > once for each ct. Florian's patch fixes the Oops :-) -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -487,7 +487,7 @@ static int nf_nat_proto_clean(struct nf_conn *i, void *data) if (clean->hash) { spin_lock_bh(&nf_nat_lock); - hlist_del_rcu(&nat->bysource); + hlist_del_init_rcu(&nat->bysource); spin_unlock_bh(&nf_nat_lock); } else {