[PATCH 4.14 031/101] tipc: use lock_sock() in tipc_sk_reinit()

From: Greg Kroah-Hartman
Date: Mon Jan 07 2019 - 08:01:05 EST

4.14-stable review patch. If anyone has any objections, please let me know.


From: Cong Wang <xiyou.wangcong@xxxxxxxxx>

[ 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 <dvyukov@xxxxxxxxxx>
Cc: Ying Xue <ying.xue@xxxxxxxxxxxxx>
Cc: Jon Maloy <jon.maloy@xxxxxxxxxxxx>
Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
net/tipc/socket.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2261,11 +2261,15 @@ 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);