From 4d97480b1806e883eb1c7889d4e7a87e936e06d9 Mon Sep 17 00:00:00 2001 From: Mitsuo Hayasaka Date: Wed, 12 Oct 2011 16:04:29 +0000 Subject: [PATCH] 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 Cc: Jay Vosburgh Cc: Andy Gospodarek Cc: Eric Dumazet Cc: WANG Cong Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 6d79b78cfc75..de3d351ccb6b 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); } } -- 2.30.2