[ 18/22] ipv6: take rtnl_lock and mark mrt6 table as freed on namespace cleanup

Greg Kroah-Hartman
2013-08-09T01:42:52Z

From: Hannes Frederic Sowa <hannes@stressinduktion.org>

[ Upstream commit 905a6f96a1b18e490a75f810d733ced93c39b0e5 ]

Otherwise we end up dereferencing the already freed net->ipv6.mrt pointer
which leads to a panic (from Srivatsa S. Bhat):

BUG: unable to handle kernel paging request at ffff882018552020
IP: [<ffffffffa0366b02>] ip6mr_sk_done+0x32/0xb0 [ipv6]
PGD 290a067 PUD 207ffe0067 PMD 207ff1d067 PTE 8000002018552060
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
Modules linked in: ebtable_nat ebtables nfs fscache nf_conntrack_ipv4 nf_defrag_ipv4 ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables nfsd lockd nfs_acl exportfs auth_rpcgss autofs4 sunrpc 8021q garp bridge stp llc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter
+ip6_tables ipv6 vfat fat vhost_net macvtap macvlan vhost tun kvm_intel kvm uinput iTCO_wdt iTCO_vendor_support cdc_ether usbnet mii microcode i2c_i801 i2c_core lpc_ich mfd_core shpchp ioatdma dca mlx4_core be2net wmi acpi_cpufreq mperf ext4 jbd2 mbcache dm_mirror dm_region_hash dm_log dm_mod
CPU: 0 PID: 7 Comm: kworker/u33:0 Not tainted 3.11.0-rc1-ea45e-a #4
Hardware name: IBM -[8737R2A]-/00Y2738, BIOS -[B2E120RUS-1.20]- 11/30/2012
Workqueue: netns cleanup_net
task: ffff8810393641c0 ti: ffff881039366000 task.ti: ffff881039366000
RIP: 0010:[<ffffffffa0366b02>] [<ffffffffa0366b02>] ip6mr_sk_done+0x32/0xb0 [ipv6]
RSP: 0018:ffff881039367bd8 EFLAGS: 00010286
RAX: ffff881039367fd8 RBX: ffff882018552000 RCX: dead000000200200
RDX: 0000000000000000 RSI: ffff881039367b68 RDI: ffff881039367b68
RBP: ffff881039367bf8 R08: ffff881039367b68 R09: 2222222222222222
R10: 2222222222222222 R11: 2222222222222222 R12: ffff882015a7a040
R13: ffff882014eb89c0 R14: ffff8820289e2800 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88103fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff882018552020 CR3: 0000000001c0b000 CR4: 00000000000407f0
Stack:
ffff881039367c18 ffff882014eb89c0 ffff882015e28c00 0000000000000000
ffff881039367c18 ffffffffa034d9d1 ffff8820289e2800 ffff882014eb89c0
ffff881039367c58 ffffffff815bdecb ffffffff815bddf2 ffff882014eb89c0
Call Trace:
[<ffffffffa034d9d1>] rawv6_close+0x21/0x40 [ipv6]
[<ffffffff815bdecb>] inet_release+0xfb/0x220
[<ffffffff815bddf2>] ? inet_release+0x22/0x220
[<ffffffffa032686f>] inet6_release+0x3f/0x50 [ipv6]
[<ffffffff8151c1d9>] sock_release+0x29/0xa0
[<ffffffff81525520>] sk_release_kernel+0x30/0x70
[<ffffffffa034f14b>] icmpv6_sk_exit+0x3b/0x80 [ipv6]
[<ffffffff8152fff9>] ops_exit_list+0x39/0x60
[<ffffffff815306fb>] cleanup_net+0xfb/0x1a0
[<ffffffff81075e3a>] process_one_work+0x1da/0x610
[<ffffffff81075dc9>] ? process_one_work+0x169/0x610
[<ffffffff81076390>] worker_thread+0x120/0x3a0
[<ffffffff81076270>] ? process_one_work+0x610/0x610
[<ffffffff8107da2e>] kthread+0xee/0x100
[<ffffffff8107d940>] ? __init_kthread_worker+0x70/0x70
[<ffffffff8162a99c>] ret_from_fork+0x7c/0xb0
[<ffffffff8107d940>] ? __init_kthread_worker+0x70/0x70
Code: 20 48 89 5d e8 4c 89 65 f0 4c 89 6d f8 66 66 66 66 90 4c 8b 67 30 49 89 fd e8 db 3c 1e e1 49 8b 9c 24 90 08 00 00 48 85 db 74 06 <4c> 39 6b 20 74 20 bb f3 ff ff ff e8 8e 3c 1e e1 89 d8 4c 8b 65
RIP [<ffffffffa0366b02>] ip6mr_sk_done+0x32/0xb0 [ipv6]
RSP <ffff881039367bd8>
CR2: ffff882018552020

Reported-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Tested-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv6/ip6mr.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/net/ipv6/ip6mr.c
+++ b/net/ipv6/ip6mr.c
@@ -256,10 +256,12 @@ static void __net_exit ip6mr_rules_exit(
{
struct mr6_table *mrt, *next;

+ rtnl_lock();
list_for_each_entry_safe(mrt, next, &net->ipv6.mr6_tables, list) {
list_del(&mrt->list);
ip6mr_free_table(mrt);
}
+ rtnl_unlock();
fib_rules_unregister(net->ipv6.mr6_rules_ops);
}
#else
@@ -286,7 +288,10 @@ static int __net_init ip6mr_rules_init(s

static void __net_exit ip6mr_rules_exit(struct net *net)
{
+ rtnl_lock();
ip6mr_free_table(net->ipv6.mrt6);
+ net->ipv6.mrt6 = NULL;
+ rtnl_unlock();
}
#endif