diff options
| author | Ben Pfaff <blp@nicira.com> | 2011-09-29 09:49:37 -0700 |
|---|---|---|
| committer | Ben Pfaff <blp@nicira.com> | 2011-09-29 10:52:35 -0700 |
| commit | 954fde3f2e68ba41f2f32faf5dbd900ce1b699a5 (patch) | |
| tree | 64f9b33ac96cd02246d78e83f4f6ea33b29b4f7f | |
| parent | 3fc5a86ab3e7168993a51ed3e71e25eda40f71fe (diff) | |
datapath: Avoid use-after-free error in dp_device_event().
Commit f14d80834 "datapath: genl_notify() on port disappearances" frees the
vport before passing it to ovs_vport_cmd_build_info(), which reads the
freed data.
Without this commit, the following commands consistently trigger a kernel
BUG report on my test VM (which has slab debugging enabled) on 3 attempts:
tunctl
ovs-vsctl add-port br0 tap0
tunctl -d tap0
With this commit, I consistently don't see the BUG, on a few hundred tries
in a tight loop.
The interesting log information is:
device tap0 entered promiscuous mode
device tap0 left promiscuous mode
BUG: unable to handle kernel paging request at 6b6b6ba7
IP: [<c88269ed>] get_vport_protected+0x8/0x52 [openvswitch_mod]
*pde = 00000000
Oops: 0000 [#1] SMP
last sysfs file: /sys/devices/pci0000:00/0000:00:04.0/net/eth1/carrier
Modules linked in: brcompat_mod openvswitch_mod
Pid: 653, comm: tunctl Not tainted 2.6.37+ #25 /Bochs
EIP: 0060:[<c88269ed>] EFLAGS: 00010246 CPU: 0
EIP is at get_vport_protected+0x8/0x52 [openvswitch_mod]
EAX: 6b6b6ba7 EBX: 00000000 ECX: 00000000 EDX: 00000000
ESI: c6d98400 EDI: c5c32074 EBP: c6ff1de8 ESP: c6ff1de4
DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068
Process tunctl (pid: 653, ti=c6ff0000 task=c5c3a820 task.ti=c6ff0000)
Stack:
00000000 c6ff1df8 c8826b1d 6b6b6b6b c6d77ab0 c6ff1e14 c8826dc6 c7489160
00000f40 c6d98400 c6d77ab0 00000000 c6ff1e3c c88286fa 00000000 00000000
00000002 02ff1e34 00000000 c6d77ab0 c6df98a0 00000006 c6ff1e54 c8828aa2
Call Trace:
[<c8826b1d>] ? get_dpifindex+0x1b/0x31 [openvswitch_mod]
[<c8826dc6>] ? ovs_vport_cmd_fill_info+0x40/0x183 [openvswitch_mod]
[<c88286fa>] ? ovs_vport_cmd_build_info+0x3f/0x62 [openvswitch_mod]
[<c8828aa2>] ? dp_device_event+0x56/0xb0 [openvswitch_mod]
[<c1046c0d>] ? notifier_call_chain+0x6d/0x96
[<c1046c52>] ? raw_notifier_call_chain+0xc/0xe
[<c1254c10>] ? call_netdevice_notifiers+0x3c/0x43
[<c1255029>] ? rollback_registered_many+0xd4/0x18b
[<c1255146>] ? rollback_registered+0x23/0x28
[<c1255199>] ? unregister_netdevice_queue+0x4e/0x6b
[<c1227d2e>] ? tun_chr_close+0x3f/0x76
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
| -rw-r--r-- | datapath/dp_notify.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/datapath/dp_notify.c b/datapath/dp_notify.c index 942d628c..07fd222d 100644 --- a/datapath/dp_notify.c +++ b/datapath/dp_notify.c @@ -37,9 +37,9 @@ static int dp_device_event(struct notifier_block *unused, unsigned long event, if (!is_internal_dev(dev)) { struct sk_buff *reply; - dp_detach_port(vport); reply = ovs_vport_cmd_build_info(vport, 0, 0, OVS_VPORT_CMD_DEL); + dp_detach_port(vport); if (IS_ERR(reply)) { netlink_set_err(INIT_NET_GENL_SOCK, 0, dp_vport_multicast_group.id, |