wireguard: use synchronize_net rather than synchronize_rcu

Many of the synchronization points are sometimes called under the rtnl
lock, which means we should use synchronize_net rather than
synchronize_rcu. Under the hood, this expands to using the expedited
flavor of function in the event that rtnl is held, in order to not stall
other concurrent changes.

This fixes some very, very long delays when removing multiple peers at
once, which would cause some operations to take several minutes.

Fixes: 4dff5496e367 ("net: WireGuard secure network tunnel")
Cc: stable@vger.kernel.org
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/wireguard/peer.c b/drivers/net/wireguard/peer.c
index cd5cb0292cb6752bd5eac2f0a111e1eec9fd393a..3a042d28eb2ea2282c8c2f41e048ae42dca54d1d 100644 (file)
--- a/drivers/net/wireguard/peer.c
+++ b/drivers/net/wireguard/peer.c
@@ -88,7 +88,7 @@ static void peer_make_dead(struct wg_peer *peer)
        /* Mark as dead, so that we don't allow jumping contexts after. */
        WRITE_ONCE(peer->is_dead, true);
 
-       /* The caller must now synchronize_rcu() for this to take effect. */
+       /* The caller must now synchronize_net() for this to take effect. */
 }
 
 static void peer_remove_after_dead(struct wg_peer *peer)
@@ -160,7 +160,7 @@ void wg_peer_remove(struct wg_peer *peer)
        lockdep_assert_held(&peer->device->device_update_lock);
 
        peer_make_dead(peer);
-       synchronize_rcu();
+       synchronize_net();
        peer_remove_after_dead(peer);
 }
 
@@ -178,7 +178,7 @@ void wg_peer_remove_all(struct wg_device *wg)
                peer_make_dead(peer);
                list_add_tail(&peer->peer_list, &dead_peers);
        }
-       synchronize_rcu();
+       synchronize_net();
        list_for_each_entry_safe(peer, temp, &dead_peers, peer_list)
                peer_remove_after_dead(peer);
 }

diff --git a/drivers/net/wireguard/socket.c b/drivers/net/wireguard/socket.c
index d9ad850daa7932b93e6dc982eccc1d22a4cc7ca3..8c496b7471082eb6c093154d7a05662718f9999c 100644 (file)
--- a/drivers/net/wireguard/socket.c
+++ b/drivers/net/wireguard/socket.c
@@ -430,7 +430,7 @@ void wg_socket_reinit(struct wg_device *wg, struct sock *new4,
        if (new4)
                wg->incoming_port = ntohs(inet_sk(new4)->inet_sport);
        mutex_unlock(&wg->socket_update_lock);
-       synchronize_rcu();
+       synchronize_net();
        sock_free(old4);
        sock_free(old6);
 }