[IPV6] route6/fib6: Don't panic a kmem_cache_create.

If the kmem_cache_creation fails, the kernel will panic. It is
acceptable if the system is booting, but if the ipv6 protocol is
compiled as a module and it is loaded after the system has booted, do
we want to panic instead of just failing to initialize the protocol ?

The init function is now returning an error and this one is checked
for protocol initialization. So the ipv6 protocol will safely fails.
Signed-off-by: NDaniel Lezcano <dlezcano@fr.ibm.com>
Acked-by: NBenjamin Thery <benjamin.thery@bull.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/ip6_fib.c

@@ -1478,8 +1478,11 @@ int __init fib6_init(void)
 	int ret;
 	fib6_node_kmem = kmem_cache_create("fib6_nodes",
 					   sizeof(struct fib6_node),
-					   0, SLAB_HWCACHE_ALIGN|SLAB_PANIC,
+					   0, SLAB_HWCACHE_ALIGN,
 					   NULL);
+	if (!fib6_node_kmem)
+		return -ENOMEM;
+
 	fib6_tables_init();
 
 	ret = __rtnl_register(PF_INET6, RTM_GETROUTE, NULL, inet6_dump_fib);

net/ipv6/route.c

@@ -2474,7 +2474,10 @@ int __init ip6_route_init(void)
 
 	ip6_dst_ops.kmem_cachep =
 		kmem_cache_create("ip6_dst_cache", sizeof(struct rt6_info), 0,
-				  SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
+				  SLAB_HWCACHE_ALIGN, NULL);
+	if (!ip6_dst_ops.kmem_cachep)
+		return -ENOMEM;
+
 	ip6_dst_blackhole_ops.kmem_cachep = ip6_dst_ops.kmem_cachep;
 
 	ret = fib6_init();