bonding: use local function pointer of bond->recv_probe in bond_handle_frame
The bond->recv_probe is called in bond_handle_frame() when
a packet is received, but bond_close() sets it to NULL. So,
a panic occurs when both functions work in parallel.
Why this happen:
After null pointer check of bond->recv_probe, an sk_buff is
duplicated and bond->recv_probe is called in bond_handle_frame.
So, a panic occurs when bond_close() is called between the
check and call of bond->recv_probe.
Patch:
This patch uses a local function pointer of bond->recv_probe
in bond_handle_frame(). So, it can avoid the null pointer
dereference.
Signed-off-by: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
Cc: Jay Vosburgh <fubar@us.ibm.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 6d79b78..de3d351 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1435,6 +1435,8 @@
struct sk_buff *skb = *pskb;
struct slave *slave;
struct bonding *bond;
+ void (*recv_probe)(struct sk_buff *, struct bonding *,
+ struct slave *);
skb = skb_share_check(skb, GFP_ATOMIC);
if (unlikely(!skb))
@@ -1448,11 +1450,12 @@
if (bond->params.arp_interval)
slave->dev->last_rx = jiffies;
- if (bond->recv_probe) {
+ recv_probe = ACCESS_ONCE(bond->recv_probe);
+ if (recv_probe) {
struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
if (likely(nskb)) {
- bond->recv_probe(nskb, bond, slave);
+ recv_probe(nskb, bond, slave);
dev_kfree_skb(nskb);
}
}