| Date | Wed, 09 Nov 2011 13:27:37 -0800 | From | Greg KH <> | Subject | [135/262] bonding: use local function pointer of bond->recv_probe in bond_handle_frame |
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3.0-stable review patch. If anyone has any objections, please let me know.
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From: Mitsuo Hayasaka <mitsuo.hayasaka.hu@hitachi.com>
[ Upstream commit 4d97480b1806e883eb1c7889d4e7a87e936e06d9 ]
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- drivers/net/bonding/bond_main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1500,6 +1500,8 @@ static rx_handler_result_t bond_handle_f 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)) @@ -1513,11 +1515,12 @@ static rx_handler_result_t bond_handle_f 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); } }
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