ipvs: fix memory leak in ip_vs_ctl.c

commit f30bf2a5 upstream.

Fix memory leak introduced in commit a0840e2e ("IPVS: netns,
ip_vs_ctl local vars moved to ipvs struct."):

unreferenced object 0xffff88005785b800 (size 2048):
  comm "(-localed)", pid 1434, jiffies 4294755650 (age 1421.089s)
  hex dump (first 32 bytes):
    bb 89 0b 83 ff ff ff ff b0 78 f0 4e 00 88 ff ff  .........x.N....
    04 00 00 00 a4 01 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<ffffffff8262ea8e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811fba74>] __kmalloc_track_caller+0x244/0x430
    [<ffffffff811b88a0>] kmemdup+0x20/0x50
    [<ffffffff823276b7>] ip_vs_control_net_init+0x1f7/0x510
    [<ffffffff8231d630>] __ip_vs_init+0x100/0x250
    [<ffffffff822363a1>] ops_init+0x41/0x190
    [<ffffffff82236583>] setup_net+0x93/0x150
    [<ffffffff82236cc2>] copy_net_ns+0x82/0x140
    [<ffffffff810ab13d>] create_new_namespaces+0xfd/0x190
    [<ffffffff810ab49a>] unshare_nsproxy_namespaces+0x5a/0xc0
    [<ffffffff810833e3>] SyS_unshare+0x173/0x310
    [<ffffffff8265cbd7>] system_call_fastpath+0x12/0x6f
    [<ffffffffffffffff>] 0xffffffffffffffff

Fixes: a0840e2e ("IPVS: netns, ip_vs_ctl local vars moved to ipvs struct.")
Signed-off-by: Tommi Rantala <tt.rantala@gmail.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

net/netfilter/ipvs/ip_vs_ctl.c

@@ -3779,6 +3779,9 @@ static void __net_exit ip_vs_control_net_cleanup_sysctl(struct net *net)
 	cancel_work_sync(&ipvs->defense_work.work);
 	unregister_net_sysctl_table(ipvs->sysctl_hdr);
 	ip_vs_stop_estimator(net, &ipvs->tot_stats);
+
+	if (!net_eq(net, &init_net))
+		kfree(ipvs->sysctl_tbl);
 }
 
 #else