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 <[email protected]>
---
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 942d628..07fd222 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,
--
1.7.4.4
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