Messages in this thread | | | Date | Tue, 22 May 2012 21:23:32 +0900 | From | Chanyeol Park <> | Subject | Re: [RFC/PATCH] Bluetooth: prevent double l2cap_chan_destroy |
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Hi
On 2012년 05월 22일 11:50, Minho Ban wrote: > @@ -1343,10 +1343,10 @@ static void l2cap_conn_del(struct hci_conn *hcon, int err) > l2cap_chan_lock(chan); > > l2cap_chan_del(chan, err); > + chan->ops->close(chan->data); > > l2cap_chan_unlock(chan); > > - chan->ops->close(chan->data); > l2cap_chan_put(chan); > } I think this patch does not make sense Because inside chan->ops->close() "chan" could be freed in the l2cap_chan_destroy().
> close callback must locate within chan_lock unless it can be scheduled to other thread > which may wait for chan_lock in l2cap_sock_shutdown and this lead to duplicate sock_kill. > > static void l2cap_sock_kill(struct sock *sk) > { > - if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket) > + if (!sock_flag(sk, SOCK_ZAPPED) || sock_flag(sk, SOCK_DEAD) || > + sk->sk_socket) > return; > > BT_DBG("sk %p state %s", sk, state_to_string(sk->sk_state)); > > Duplicate sock_kill may happen anyway, need test SOCK_DEAD if chan_destroy is already called. Even l2cap_sock_kill() is called twice, " if (!sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket)" can't filter it. I tested Mr.ban case. it works fine with me.
BR Chanyeol Park.
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