Re: [PATCH 1/3] bluetooth: add write_lock_bh to __l2cap_chan_link

From: Marcel Holtmann
Date: Sat Feb 28 2009 - 16:33:43 EST


Hi Gustavo,

> fix race condition
>
> Signed-off-by: Gustavo F. Padovan <gustavo@xxxxxxxxxxxxxxxxx>
> ---
> net/bluetooth/l2cap.c | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/net/bluetooth/l2cap.c b/net/bluetooth/l2cap.c
> index ca4d3b4..355f375 100644
> --- a/net/bluetooth/l2cap.c
> +++ b/net/bluetooth/l2cap.c
> @@ -175,12 +175,14 @@ static inline void __l2cap_chan_link(struct l2cap_chan_list *l, struct sock *sk)
> {
> sock_hold(sk);
>
> + write_lock_bh(&l->lock);
> if (l->head)
> l2cap_pi(l->head)->prev_c = sk;
>
> l2cap_pi(sk)->next_c = l->head;
> l2cap_pi(sk)->prev_c = NULL;
> l->head = sk;
> + write_unlock_bh(&l->lock);
> }

a general rule of thumb is that function starting with __ are the ones
that don't use any kind of locking.

Regards

Marcel


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