4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Cong Wang <[email protected]> [ Upstream commit 15ef70e286176165d28b0b8a969b422561a68dfc ] 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(). 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]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/tipc/socket.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -2281,11 +2281,15 @@ void tipc_sk_reinit(struct net *net) goto walk_stop; 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, tn->own_addr); msg_set_orignode(msg, tn->own_addr); - spin_unlock_bh(&tsk->sk.sk_lock.slock); + release_sock(&tsk->sk); + rhashtable_walk_start(&iter); + sock_put(&tsk->sk); } walk_stop: rhashtable_walk_stop(&iter);
