linux-kernel - [PATCH 3.4 118/125] ipv6: don't call fib6_run

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Date:   Wed, 12 Oct 2016 20:33:54 +0800
From:   lizf@...nel.org
To:     stable@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Michal Kubeček <mkubecek@...e.cz>,
        "David S. Miller" <davem@...emloft.net>,
        Zefan Li <lizefan@...wei.com>
Subject: [PATCH 3.4 118/125] ipv6: don't call fib6_run_gc() until routing is ready

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

3.4.113-rc1 review patch.  If anyone has any objections, please let me know.

------------------


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>
Signed-off-by: Zefan Li <lizefan@...wei.com>
---
 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 6f9c25a..cd205e9 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -117,7 +117,9 @@ static inline struct neighbour *__ipv6_neigh_lookup(struct neigh_table *tbl, str
 }
 
 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 5300ef3..8ddb56f 100644
--- a/net/ipv6/af_inet6.c
+++ b/net/ipv6/af_inet6.c
@@ -1161,6 +1161,9 @@ 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;
@@ -1221,6 +1224,8 @@ 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
@@ -1288,6 +1293,7 @@ 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 e235b4c..02e6568 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1867,24 +1867,28 @@ 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
-- 
1.9.1