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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-11-02 22:47:44 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-11-03 18:02:13 -0400 |
| commit | e2e210c0238eb7073e07af503ae743fa53977120 (patch) | |
| tree | a4940a436eb0292f09a9e9c09d7bfccfc5a0d76f | |
| parent | 2edcd4ca43df3c1d1d392753531cc73a53e709ba (diff) | |
| download | linux-e2e210c0238eb7073e07af503ae743fa53977120.tar.gz linux-e2e210c0238eb7073e07af503ae743fa53977120.tar.bz2 linux-e2e210c0238eb7073e07af503ae743fa53977120.zip | |
l2tp: fix race in l2tp_recv_dequeue()
Misha Labjuk reported panics occurring in l2tp_recv_dequeue()
If we release reorder_q.lock, we must not keep a dangling pointer (tmp),
since another thread could manipulate reorder_q.
Instead we must restart the scan at beginning of list.
Reported-by: Misha Labjuk <spiked.yar@gmail.com>
Tested-by: Misha Labjuk <spiked.yar@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/l2tp/l2tp_core.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c index 34b2ddeacb67..bf8d50c67931 100644 --- a/net/l2tp/l2tp_core.c +++ b/net/l2tp/l2tp_core.c @@ -397,6 +397,7 @@ static void l2tp_recv_dequeue(struct l2tp_session *session) * expect to send up next, dequeue it and any other * in-sequence packets behind it. */ +start: spin_lock_bh(&session->reorder_q.lock); skb_queue_walk_safe(&session->reorder_q, skb, tmp) { if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) { @@ -433,7 +434,7 @@ static void l2tp_recv_dequeue(struct l2tp_session *session) */ spin_unlock_bh(&session->reorder_q.lock); l2tp_recv_dequeue_skb(session, skb); - spin_lock_bh(&session->reorder_q.lock); + goto start; } out: |