wireguard: use synchronize_net rather than synchronize_rcu

BugLink: https://bugs.launchpad.net/bugs/1933691
commit 24b70eeeb4f46c09487f8155239ebfb1f875774a upstream.

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: e7096c131e51 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

diff --git a/drivers/net/wireguard/peer.c b/drivers/net/wireguard/peer.c
index 6936a82364bf74a456ac40f2ea832358688d0caa..1acd00ab2fbcbf0ac5faabae474bf6ec16dcf30c 100644 (file)
--- a/drivers/net/wireguard/peer.c
+++ b/drivers/net/wireguard/peer.c
@@ -89,7 +89,7 @@ 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)
@@ -161,7 +161,7 @@ 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);
 }
 
@@ -179,7 +179,7 @@ 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 410b318e57fb941140fb3e6161eb876fb0d7fa42..181373f4a0afd0ca7f5ddf0f6eeb83074a3db412 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);
 }