[NET]: fix oops after tunnel module unload

Tunnel modules used to obtain module refcount each time when some tunnel was created, which meaned that tunnel could be unloaded only after all the tunnels are deleted. Since killing old MOD_*_USE_COUNT macros this protection has gone. It is possible to return it back as module_get/put, but it looks more natural and practically useful to force destruction of all the child tunnels on module unload. Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>

[NET]: fix oops after tunnel module unload
Tunnel modules used to obtain module refcount each time when some tunnel was created, which meaned that tunnel could be unloaded only after all the tunnels are deleted. Since killing old MOD_*_USE_COUNT macros this protection has gone. It is possible to return it back as module_get/put, but it looks more natural and practically useful to force destruction of all the child tunnels on module unload. Signed-off-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by: David S. Miller <davem@davemloft.net>
Alexey Kuznetsov · David S. Miller
1 parent 1f494c0e04
Showing 3 changed files with 55 additions and 7 deletions Side-by-side Diff
net/ipv4/ip_gre.c
net/ipv4/ipip.c
net/ipv6/sit.c
@@ -290,7 +290,6 @@
  
 	dev_hold(dev);
 	ipgre_tunnel_link(nt);
-	/* Do not decrement MOD_USE_COUNT here. */
 	return nt;
  
 failed:
  
  
@@ -1277,12 +1276,28 @@
 	goto out;
 }
  
-static void ipgre_fini(void)
+static void __exit ipgre_destroy_tunnels(void)
 {
+	int prio;
+
+	for (prio = 0; prio < 4; prio++) {
+		int h;
+		for (h = 0; h < HASH_SIZE; h++) {
+			struct ip_tunnel *t;
+			while ((t = tunnels[prio][h]) != NULL)
+				unregister_netdevice(t->dev);
+		}
+	}
+}
+
+static void __exit ipgre_fini(void)
+{
 	if (inet_del_protocol(&ipgre_protocol, IPPROTO_GRE) < 0)
 		printk(KERN_INFO "ipgre close: can't remove protocol\n");
  
-	unregister_netdev(ipgre_fb_tunnel_dev);
+	rtnl_lock();
+	ipgre_destroy_tunnels();
+	rtnl_unlock();
 }
  
 module_init(ipgre_init);
@@ -255,7 +255,6 @@
  
 	dev_hold(dev);
 	ipip_tunnel_link(nt);
-	/* Do not decrement MOD_USE_COUNT here. */
 	return nt;
  
 failed:
  
@@ -920,12 +919,29 @@
 	goto out;
 }
  
+static void __exit ipip_destroy_tunnels(void)
+{
+	int prio;
+
+	for (prio = 1; prio < 4; prio++) {
+		int h;
+		for (h = 0; h < HASH_SIZE; h++) {
+			struct ip_tunnel *t;
+			while ((t = tunnels[prio][h]) != NULL)
+				unregister_netdevice(t->dev);
+		}
+	}
+}
+
 static void __exit ipip_fini(void)
 {
 	if (ipip_unregister() < 0)
 		printk(KERN_INFO "ipip close: can't deregister tunnel\n");
  
-	unregister_netdev(ipip_fb_tunnel_dev);
+	rtnl_lock();
+	ipip_destroy_tunnels();
+	unregister_netdevice(ipip_fb_tunnel_dev);
+	rtnl_unlock();
 }
  
 module_init(ipip_init);
@@ -195,7 +195,6 @@
 	dev_hold(dev);
  
 	ipip6_tunnel_link(nt);
-	/* Do not decrement MOD_USE_COUNT here. */
 	return nt;
  
 failed:
  
@@ -794,10 +793,28 @@
 	.err_handler	=	ipip6_err,
 };
  
+static void __exit sit_destroy_tunnels(void)
+{
+	int prio;
+
+	for (prio = 1; prio < 4; prio++) {
+		int h;
+		for (h = 0; h < HASH_SIZE; h++) {
+			struct ip_tunnel *t;
+			while ((t = tunnels[prio][h]) != NULL)
+				unregister_netdevice(t->dev);
+		}
+	}
+}
+
 void __exit sit_cleanup(void)
 {
 	inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
-	unregister_netdev(ipip6_fb_tunnel_dev);
+
+	rtnl_lock();
+	sit_destroy_tunnels();
+	unregister_netdevice(ipip6_fb_tunnel_dev);
+	rtnl_unlock();
 }
  
 int __init sit_init(void)
...	...	@@ -290,7 +290,6 @@
290	290
291	291	dev_hold(dev);
292	292	ipgre_tunnel_link(nt);
293		- /* Do not decrement MOD_USE_COUNT here. */
294	293	return nt;
295	294
296	295	failed:
297	296
298	297
...	...	@@ -1277,12 +1276,28 @@
1277	1276	goto out;
1278	1277	}
1279	1278
1280		-static void ipgre_fini(void)
	1279	+static void __exit ipgre_destroy_tunnels(void)
1281	1280	{
	1281	+ int prio;
	1282	+
	1283	+ for (prio = 0; prio < 4; prio++) {
	1284	+ int h;
	1285	+ for (h = 0; h < HASH_SIZE; h++) {
	1286	+ struct ip_tunnel *t;
	1287	+ while ((t = tunnels[prio][h]) != NULL)
	1288	+ unregister_netdevice(t->dev);
	1289	+ }
	1290	+ }
	1291	+}
	1292	+
	1293	+static void __exit ipgre_fini(void)
	1294	+{
1282	1295	if (inet_del_protocol(&ipgre_protocol, IPPROTO_GRE) < 0)
1283	1296	printk(KERN_INFO "ipgre close: can't remove protocol\n");
1284	1297
1285		- unregister_netdev(ipgre_fb_tunnel_dev);
	1298	+ rtnl_lock();
	1299	+ ipgre_destroy_tunnels();
	1300	+ rtnl_unlock();
1286	1301	}
1287	1302
1288	1303	module_init(ipgre_init);
...	...	@@ -255,7 +255,6 @@
255	255
256	256	dev_hold(dev);
257	257	ipip_tunnel_link(nt);
258		- /* Do not decrement MOD_USE_COUNT here. */
259	258	return nt;
260	259
261	260	failed:
262	261
...	...	@@ -920,12 +919,29 @@
920	919	goto out;
921	920	}
922	921
	922	+static void __exit ipip_destroy_tunnels(void)
	923	+{
	924	+ int prio;
	925	+
	926	+ for (prio = 1; prio < 4; prio++) {
	927	+ int h;
	928	+ for (h = 0; h < HASH_SIZE; h++) {
	929	+ struct ip_tunnel *t;
	930	+ while ((t = tunnels[prio][h]) != NULL)
	931	+ unregister_netdevice(t->dev);
	932	+ }
	933	+ }
	934	+}
	935	+
923	936	static void __exit ipip_fini(void)
924	937	{
925	938	if (ipip_unregister() < 0)
926	939	printk(KERN_INFO "ipip close: can't deregister tunnel\n");
927	940
928		- unregister_netdev(ipip_fb_tunnel_dev);
	941	+ rtnl_lock();
	942	+ ipip_destroy_tunnels();
	943	+ unregister_netdevice(ipip_fb_tunnel_dev);
	944	+ rtnl_unlock();
929	945	}
930	946
931	947	module_init(ipip_init);
...	...	@@ -195,7 +195,6 @@
195	195	dev_hold(dev);
196	196
197	197	ipip6_tunnel_link(nt);
198		- /* Do not decrement MOD_USE_COUNT here. */
199	198	return nt;
200	199
201	200	failed:
202	201
...	...	@@ -794,10 +793,28 @@
794	793	.err_handler = ipip6_err,
795	794	};
796	795
	796	+static void __exit sit_destroy_tunnels(void)
	797	+{
	798	+ int prio;
	799	+
	800	+ for (prio = 1; prio < 4; prio++) {
	801	+ int h;
	802	+ for (h = 0; h < HASH_SIZE; h++) {
	803	+ struct ip_tunnel *t;
	804	+ while ((t = tunnels[prio][h]) != NULL)
	805	+ unregister_netdevice(t->dev);
	806	+ }
	807	+ }
	808	+}
	809	+
797	810	void __exit sit_cleanup(void)
798	811	{
799	812	inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
800		- unregister_netdev(ipip6_fb_tunnel_dev);
	813	+
	814	+ rtnl_lock();
	815	+ sit_destroy_tunnels();
	816	+ unregister_netdevice(ipip6_fb_tunnel_dev);
	817	+ rtnl_unlock();
801	818	}
802	819
803	820	int __init sit_init(void)