[PATCH net-next] ipv6: don't free static mem in the case of init_net

[PATCH net-next] ipv6: don't free static mem in the case of init_net

[Hong Zhiguo]

Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
---
 net/ipv6/addrconf.c |    8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index fa36a67..1f5f51f 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4891,10 +4891,14 @@ static int __net_init addrconf_init_net(struct net *net)
 err_reg_dflt:
 	__addrconf_sysctl_unregister(all);
 err_reg_all:
-	kfree(dflt);
+	if (dflt != &ipv6_devconf_dflt) {
+		kfree(dflt);
+	}
 #endif
 err_alloc_dflt:
-	kfree(all);
+	if (all != &ipv6_devconf) {
+		kfree(all);
+	}
 err_alloc_all:
 	return err;
 }
-- 
1.7.10.4

Re: [PATCH net-next] ipv6: don't free static mem in the case of init_net

[David Miller]

From: Hong Zhiguo <honkiko@gmail.com>
Date: Tue, 26 Mar 2013 00:25:25 +0800

> Signed-off-by: Hong Zhiguo <honkiko@gmail.com>

1) This should be submitted against 'net' since it's clearly
   a real bug.

2) This needs to be fixed differently.  We should always
   kmemdup() and create fresh copies of these objects, even
   for init_net.  So 'dflt' and 'all' will start as "NULL"
   and always we will try to kmemdup(&ipv6_defconf, ...) and
   kmemdup(&ipv6_devconf_dflt, ...);