target/linux/generic/backport-5.4/080-wireguard-0130-wireguard-use-synchronize_net-rather-than-synchroniz.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: "Jason A. Donenfeld" <Jason@zx2c4.com>
   3 Date: Fri, 4 Jun 2021 17:17:33 +0200
   4 Subject: [PATCH] wireguard: use synchronize_net rather than synchronize_rcu
   5
   6 commit 24b70eeeb4f46c09487f8155239ebfb1f875774a upstream.
   7
   8 Many of the synchronization points are sometimes called under the rtnl
   9 lock, which means we should use synchronize_net rather than
  10 synchronize_rcu. Under the hood, this expands to using the expedited
  11 flavor of function in the event that rtnl is held, in order to not stall
  12 other concurrent changes.
  13
  14 This fixes some very, very long delays when removing multiple peers at
  15 once, which would cause some operations to take several minutes.
  16
  17 Fixes: e7096c131e51 ("net: WireGuard secure network tunnel")
  18 Cc: stable@vger.kernel.org
  19 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  20 Signed-off-by: David S. Miller <davem@davemloft.net>
  21 Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
  22 ---
  23  drivers/net/wireguard/peer.c   | 6 +++---
  24  drivers/net/wireguard/socket.c | 2 +-
  25  2 files changed, 4 insertions(+), 4 deletions(-)
  26
  27 --- a/drivers/net/wireguard/peer.c
  28 +++ b/drivers/net/wireguard/peer.c
  29 @@ -88,7 +88,7 @@ static void peer_make_dead(struct wg_pee
  30         /* Mark as dead, so that we don't allow jumping contexts after. */
  31         WRITE_ONCE(peer->is_dead, true);
  32
  33 -       /* The caller must now synchronize_rcu() for this to take effect. */
  34 +       /* The caller must now synchronize_net() for this to take effect. */
  35  }
  36
  37  static void peer_remove_after_dead(struct wg_peer *peer)
  38 @@ -160,7 +160,7 @@ void wg_peer_remove(struct wg_peer *peer
  39         lockdep_assert_held(&peer->device->device_update_lock);
  40
  41         peer_make_dead(peer);
  42 -       synchronize_rcu();
  43 +       synchronize_net();
  44         peer_remove_after_dead(peer);
  45  }
  46
  47 @@ -178,7 +178,7 @@ void wg_peer_remove_all(struct wg_device
  48                 peer_make_dead(peer);
  49                 list_add_tail(&peer->peer_list, &dead_peers);
  50         }
  51 -       synchronize_rcu();
  52 +       synchronize_net();
  53         list_for_each_entry_safe(peer, temp, &dead_peers, peer_list)
  54                 peer_remove_after_dead(peer);
  55  }
  56 --- a/drivers/net/wireguard/socket.c
  57 +++ b/drivers/net/wireguard/socket.c
  58 @@ -430,7 +430,7 @@ void wg_socket_reinit(struct wg_device *
  59         if (new4)
  60                 wg->incoming_port = ntohs(inet_sk(new4)->inet_sport);
  61         mutex_unlock(&wg->socket_update_lock);
  62 -       synchronize_rcu();
  63 +       synchronize_net();
  64         sock_free(old4);
  65         sock_free(old6);
  66  }