On Mon, Dec 10, 2018 at 8:50 PM Cong Wang <[email protected]> wrote:
>
> lock_sock() must be used in process context to be race-free with
> other lock_sock() callers, for example, tipc_release(). Otherwise
> using the spinlock directly can't serialize a parallel tipc_release().
>
> As it is blocking, we have to hold the sock refcnt before
> rhashtable_walk_stop() and release it after rhashtable_walk_start().
Thanks for the quick fix!
> Fixes: 07f6c4bc048a ("tipc: convert tipc reference table to use generic
> rhashtable")
> Reported-by: Dmitry Vyukov <[email protected]>
> Cc: Ying Xue <[email protected]>
> Cc: Jon Maloy <[email protected]>
> Signed-off-by: Cong Wang <[email protected]>
> ---
> net/tipc/socket.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index b57b1be7252b..e1396fb87779 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -2724,11 +2724,15 @@ void tipc_sk_reinit(struct net *net)
> rhashtable_walk_start(&iter);
>
> while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
> - spin_lock_bh(&tsk->sk.sk_lock.slock);
> + sock_hold(&tsk->sk);
> + rhashtable_walk_stop(&iter);
> + lock_sock(&tsk->sk);
> msg = &tsk->phdr;
> msg_set_prevnode(msg, tipc_own_addr(net));
> msg_set_orignode(msg, tipc_own_addr(net));
> - spin_unlock_bh(&tsk->sk.sk_lock.slock);
> + release_sock(&tsk->sk);
> + rhashtable_walk_start(&iter);
> + sock_put(&tsk->sk);
> }
>
> rhashtable_walk_stop(&iter);
> --
> 2.19.2
>
