net: allow to kill a task which waits net_mutex in copy_new_ns

net_mutex can be locked for a long time. It may be because many namespaces are being destroyed or many processes decide to create a network namespace. Both these operations are heavy, so it is better to have an ability to kill a process which is waiting net_mutex. Cc: "David S. Miller" <[email protected]> Cc: Eric W. Biederman <[email protected]> Signed-off-by: Andrei Vagin <[email protected]> Signed-off-by: David S. Miller <[email protected]>
adn770 · Oct 23, 2016 · 7281a66 · 7281a66
1 parent d65f2fa
commit 7281a66
Showing 1 changed file with 8 additions and 1 deletion.
diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
@@ -379,7 +379,14 @@ struct net *copy_net_ns(unsigned long flags,
 
 	get_user_ns(user_ns);
 
-	mutex_lock(&net_mutex);
+	rv = mutex_lock_killable(&net_mutex);
+	if (rv < 0) {
+		net_free(net);
+		dec_net_namespaces(ucounts);
+		put_user_ns(user_ns);
+		return ERR_PTR(rv);
+	}
+
 	net->ucounts = ucounts;
 	rv = setup_net(net, user_ns);
 	if (rv == 0) {