ipv4_sysctl_exit_net() is currently freeing net->ipv4.sysctl_local_reserved_ports
too soon.

Only after unregister_net_sysctl_table() we can be sure no threads can possibly
use the sysctls, including /proc/sys/net/ipv4/ip_local_reserved_ports.

Fixes: 122ff243f5f1 ("ipv4: make ip_local_reserved_ports per netns")
Reported-by: Ji'an Zhou <redacted>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Cong Wang <redacted>
---
 net/ipv4/sysctl_net_ipv4.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index d8bdb1bdbff17ab52fe969b93ce13673e88c05a4..c0e85cc171aec099fd5d4897b1a623dd27eaee08 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c

@@ -1705,10 +1705,10 @@ static __net_exit void ipv4_sysctl_exit_net(struct net *net)
 {
 	const struct ctl_table *table;
 
-	kfree(net->ipv4.sysctl_local_reserved_ports);
 	table = net->ipv4.ipv4_hdr->ctl_table_arg;
 	unregister_net_sysctl_table(net->ipv4.ipv4_hdr);
 	kfree(table);
+	kfree(net->ipv4.sysctl_local_reserved_ports);
 }
 
 static __net_initdata struct pernet_operations ipv4_sysctl_ops = {

-- 
2.54.0.669.g59709faab0-goog