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authorMitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>2011-10-12 16:04:29 (GMT)
committerDavid S. Miller <davem@davemloft.net>2011-10-19 04:14:22 (GMT)
commit4d97480b1806e883eb1c7889d4e7a87e936e06d9 (patch)
tree0a690a2f5718826eb871ad655c9acddb5b84f335
parent28c213793c994e4aac5f669ce856b5682a549bbb (diff)
downloadlinux-4d97480b1806e883eb1c7889d4e7a87e936e06d9.tar.xz
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>
-rw-r--r--drivers/net/bonding/bond_main.c7
1 files changed, 5 insertions, 2 deletions
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 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
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 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
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);
}
}