[PATCH 6.1 178/195] phonet: take correct lock to peek at the RX queue

Greg Kroah-Hartman
2024-02-27T14:20:30Z

From: Rémi Denis-Courmont <courmisch@gmail.com>

[ Upstream commit 3b2d9bc4d4acdf15a876eae2c0d83149250e85ba ]

The receive queue is protected by its embedded spin-lock, not the
socket lock, so we need the former lock here (and only that one).

Fixes: 107d0d9b8d9a ("Phonet: Phonet datagram transport protocol")
Reported-by: Luosili <rootlab@huawei.com>
Signed-off-by: Rémi Denis-Courmont <courmisch@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240218081214.4806-1-remi@remlab.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/phonet/datagram.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/phonet/datagram.c
+++ b/net/phonet/datagram.c
@@ -35,10 +35,10 @@ static int pn_ioctl(struct sock *sk, int

switch (cmd) {
case SIOCINQ:
- lock_sock(sk);
+ spin_lock_bh(&sk->sk_receive_queue.lock);
skb = skb_peek(&sk->sk_receive_queue);
answ = skb ? skb->len : 0;
- release_sock(sk);
+ spin_unlock_bh(&sk->sk_receive_queue.lock);
return put_user(answ, (int __user *)arg);