ipv4: free net->ipv4.sysctl_local_reserved_ports after unregister_net_sysctl_table()

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 <eilaimemedsnaimel@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Link: https://patch.msgid.link/20260521122147.3584624-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index d8bdb1bdbff17ab52fe969b93ce13673e88c05a4..c0e85cc171aec099fd5d4897b1a623dd27eaee08 100644 (file)
--- 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 = {