From 9e2bbf9915255770836d16cd99eeb6536297079d Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Mon, 14 Jan 2019 00:30:37 +0900
Subject: [PATCH] network: make Link and NetDev always have the valid poiter to
 Manager

c4397d94c3d94909188d82e086ebedf5d3690569 introduces
link_detach_from_manager() and netdev_detach_from_manager(), and they
set Link::manager or NetDev::manager NULL.
But, at the time e.g. link is removed, hence link_drop() is called,
there may be still some asynchronous netlink call is waiting, and
their callbacks hit assertion.

This make {link,netdev}_detach_from_manager() just drop all references
from manager, but keep the pointer to manager.

Fixes #11411.
---
 src/network/netdev/netdev.c    | 9 +++++++--
 src/network/netdev/netdev.h    | 1 +
 src/network/netdev/wireguard.c | 6 ++----
 src/network/networkd-link.c    | 2 --
 4 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/network/netdev/netdev.c b/src/network/netdev/netdev.c
index f0e9d00246..65959f4a03 100644
--- a/src/network/netdev/netdev.c
+++ b/src/network/netdev/netdev.c
@@ -148,11 +148,16 @@ static void netdev_callbacks_clear(NetDev *netdev) {
         }
 }
 
+bool netdev_is_managed(NetDev *netdev) {
+        if (!netdev || !netdev->manager || !netdev->ifname)
+                return false;
+
+        return hashmap_get(netdev->manager->netdevs, netdev->ifname) == netdev;
+}
+
 static void netdev_detach_from_manager(NetDev *netdev) {
         if (netdev->ifname && netdev->manager)
                 hashmap_remove(netdev->manager->netdevs, netdev->ifname);
-
-        netdev->manager = NULL;
 }
 
 static NetDev *netdev_free(NetDev *netdev) {
diff --git a/src/network/netdev/netdev.h b/src/network/netdev/netdev.h
index bfe1094181..d6524da0f3 100644
--- a/src/network/netdev/netdev.h
+++ b/src/network/netdev/netdev.h
@@ -156,6 +156,7 @@ NetDev *netdev_ref(NetDev *netdev);
 DEFINE_TRIVIAL_DESTRUCTOR(netdev_destroy_callback, NetDev, netdev_unref);
 DEFINE_TRIVIAL_CLEANUP_FUNC(NetDev*, netdev_unref);
 
+bool netdev_is_managed(NetDev *netdev);
 int netdev_get(Manager *manager, const char *name, NetDev **ret);
 int netdev_set_ifindex(NetDev *netdev, sd_netlink_message *newlink);
 int netdev_get_mac(const char *ifname, struct ether_addr **ret);
diff --git a/src/network/netdev/wireguard.c b/src/network/netdev/wireguard.c
index 167cf65046..45b7c7c330 100644
--- a/src/network/netdev/wireguard.c
+++ b/src/network/netdev/wireguard.c
@@ -224,8 +224,7 @@ static int on_resolve_retry(sd_event_source *s, usec_t usec, void *userdata) {
         w = WIREGUARD(netdev);
         assert(w);
 
-        if (!netdev->manager)
-                /* The netdev is detached. */
+        if (!netdev_is_managed(netdev))
                 return 0;
 
         assert(!w->unresolved_endpoints);
@@ -260,8 +259,7 @@ static int wireguard_resolve_handler(sd_resolve_query *q,
         w = WIREGUARD(netdev);
         assert(w);
 
-        if (!netdev->manager)
-                /* The netdev is detached. */
+        if (!netdev_is_managed(netdev))
                 return 0;
 
         if (ret != 0) {
diff --git a/src/network/networkd-link.c b/src/network/networkd-link.c
index 5353b9daaf..3661498f39 100644
--- a/src/network/networkd-link.c
+++ b/src/network/networkd-link.c
@@ -517,8 +517,6 @@ static void link_detach_from_manager(Link *link) {
         hashmap_remove(link->manager->links, INT_TO_PTR(link->ifindex));
         set_remove(link->manager->links_requesting_uuid, link);
         link_clean(link);
-
-        link->manager = NULL;
 }
 
 static Link *link_free(Link *link) {