linux-kernel - [PATCH 3.10 219/319] ipv6: don't call fib6_run

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Message-Id: <1486322541-8206-120-git-send-email-w@1wt.eu>
Date:   Sun,  5 Feb 2017 20:20:41 +0100
From:   Willy Tarreau <w@....eu>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        linux@...ck-us.net
Cc:     Michal Kubeček <mkubecek@...e.cz>,
        "David S . Miller" <davem@...emloft.net>,
        Mike Manning <mmanning@...cade.com>, Willy Tarreau <w@....eu>
Subject: [PATCH 3.10 219/319] ipv6: don't call fib6_run_gc() until routing is ready

From: Michal Kubeček <mkubecek@...e.cz>

commit 2c861cc65ef4604011a0082e4dcdba2819aa191a upstream.

When loading the ipv6 module, ndisc_init() is called before
ip6_route_init(). As the former registers a handler calling
fib6_run_gc(), this opens a window to run the garbage collector
before necessary data structures are initialized. If a network
device is initialized in this window, adding MAC address to it
triggers a NETDEV_CHANGEADDR event, leading to a crash in
fib6_clean_all().

Take the event handler registration out of ndisc_init() into a
separate function ndisc_late_init() and move it after
ip6_route_init().

Signed-off-by: Michal Kubecek <mkubecek@...e.cz>
Signed-off-by: David S. Miller <davem@...emloft.net>
Cc: <stable@...r.kernel.org> 
Signed-off-by: Mike Manning <mmanning@...cade.com>
Signed-off-by: Willy Tarreau <w@....eu>
---
 include/net/ndisc.h |  2 ++
 net/ipv6/af_inet6.c |  6 ++++++
 net/ipv6/ndisc.c    | 18 +++++++++++-------
 3 files changed, 19 insertions(+), 7 deletions(-)

diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 5043f8b..4b12d99 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -190,7 +190,9 @@ static inline struct neighbour *__ipv6_neigh_lookup(struct net_device *dev, cons
 }
 
 extern int			ndisc_init(void);
+extern int			ndisc_late_init(void);
 
+extern void			ndisc_late_cleanup(void);
 extern void			ndisc_cleanup(void);
 
 extern int			ndisc_rcv(struct sk_buff *skb);
diff --git a/net/ipv6/af_inet6.c b/net/ipv6/af_inet6.c
index a944f13..9443af7 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -900,6 +900,9 @@ static int __init inet6_init(void)
 	err = ip6_route_init();
 	if (err)
 		goto ip6_route_fail;
+	err = ndisc_late_init();
+	if (err)
+		goto ndisc_late_fail;
 	err = ip6_flowlabel_init();
 	if (err)
 		goto ip6_flowlabel_fail;
@@ -960,6 +963,8 @@ ipv6_exthdrs_fail:
 addrconf_fail:
 	ip6_flowlabel_cleanup();
 ip6_flowlabel_fail:
+	ndisc_late_cleanup();
+ndisc_late_fail:
 	ip6_route_cleanup();
 ip6_route_fail:
 #ifdef CONFIG_PROC_FS
@@ -1020,6 +1025,7 @@ static void __exit inet6_exit(void)
 	ipv6_exthdrs_exit();
 	addrconf_cleanup();
 	ip6_flowlabel_cleanup();
+	ndisc_late_cleanup();
 	ip6_route_cleanup();
 #ifdef CONFIG_PROC_FS
 
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index deedf7d..de10ccf 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1716,24 +1716,28 @@ int __init ndisc_init(void)
 	if (err)
 		goto out_unregister_pernet;
 #endif
-	err = register_netdevice_notifier(&ndisc_netdev_notifier);
-	if (err)
-		goto out_unregister_sysctl;
 out:
 	return err;
 
-out_unregister_sysctl:
 #ifdef CONFIG_SYSCTL
-	neigh_sysctl_unregister(&nd_tbl.parms);
 out_unregister_pernet:
-#endif
 	unregister_pernet_subsys(&ndisc_net_ops);
 	goto out;
+#endif
 }
 
-void ndisc_cleanup(void)
+int __init ndisc_late_init(void)
+{
+	return register_netdevice_notifier(&ndisc_netdev_notifier);
+}
+
+void ndisc_late_cleanup(void)
 {
 	unregister_netdevice_notifier(&ndisc_netdev_notifier);
+}
+
+void ndisc_cleanup(void)
+{
 #ifdef CONFIG_SYSCTL
 	neigh_sysctl_unregister(&nd_tbl.parms);
 #endif
-- 
2.8.0.rc2.1.gbe9624a