team: Free BPF filter when unregistering netdev

When team is used in loadbalance mode a BPF filter can be used to
provide a hash which will determine the Tx port.

When the netdev is later unregistered the filter is not freed which
results in memory leaks [1].

Fix by freeing the program and the corresponding filter when
unregistering the netdev.

[1]
unreferenced object 0xffff8881dbc47cc8 (size 16):
  comm "teamd", pid 3068, jiffies 4294997779 (age 438.247s)
  hex dump (first 16 bytes):
    a3 00 6b 6b 6b 6b 6b 6b 88 a5 82 e1 81 88 ff ff  ..kkkkkk........
  backtrace:
    [<000000008a3b47e3>] team_nl_cmd_options_set+0x88f/0x11b0
    [<00000000c4f4f27e>] genl_family_rcv_msg+0x78f/0x1080
    [<00000000610ef838>] genl_rcv_msg+0xca/0x170
    [<00000000a281df93>] netlink_rcv_skb+0x132/0x380
    [<000000004d9448a2>] genl_rcv+0x29/0x40
    [<000000000321b2f4>] netlink_unicast+0x4c0/0x690
    [<000000008c25dffb>] netlink_sendmsg+0x929/0xe10
    [<00000000068298c5>] sock_sendmsg+0xc8/0x110
    [<0000000082a61ff0>] ___sys_sendmsg+0x77a/0x8f0
    [<00000000663ae29d>] __sys_sendmsg+0xf7/0x250
    [<0000000027c5f11a>] do_syscall_64+0x14d/0x610
    [<000000006cfbc8d3>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<00000000e23197e2>] 0xffffffffffffffff
unreferenced object 0xffff8881e182a588 (size 2048):
  comm "teamd", pid 3068, jiffies 4294997780 (age 438.247s)
  hex dump (first 32 bytes):
    20 00 00 00 02 00 00 00 30 00 00 00 28 f0 ff ff   .......0...(...
    07 00 00 00 00 00 00 00 28 00 00 00 00 00 00 00  ........(.......
  backtrace:
    [<000000002daf01fb>] lb_bpf_func_set+0x45c/0x6d0
    [<000000008a3b47e3>] team_nl_cmd_options_set+0x88f/0x11b0
    [<00000000c4f4f27e>] genl_family_rcv_msg+0x78f/0x1080
    [<00000000610ef838>] genl_rcv_msg+0xca/0x170
    [<00000000a281df93>] netlink_rcv_skb+0x132/0x380
    [<000000004d9448a2>] genl_rcv+0x29/0x40
    [<000000000321b2f4>] netlink_unicast+0x4c0/0x690
    [<000000008c25dffb>] netlink_sendmsg+0x929/0xe10
    [<00000000068298c5>] sock_sendmsg+0xc8/0x110
    [<0000000082a61ff0>] ___sys_sendmsg+0x77a/0x8f0
    [<00000000663ae29d>] __sys_sendmsg+0xf7/0x250
    [<0000000027c5f11a>] do_syscall_64+0x14d/0x610
    [<000000006cfbc8d3>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<00000000e23197e2>] 0xffffffffffffffff

Fixes: 01d7f30a ("team: add loadbalance mode")
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reported-by: Amit Cohen <amitc@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/team/team_mode_loadbalance.c

@@ -325,6 +325,20 @@ static int lb_bpf_func_set(struct team *team, struct team_gsetter_ctx *ctx)
 	return 0;
 }
 
+static void lb_bpf_func_free(struct team *team)
+{
+	struct lb_priv *lb_priv = get_lb_priv(team);
+	struct bpf_prog *fp;
+
+	if (!lb_priv->ex->orig_fprog)
+		return;
+
+	__fprog_destroy(lb_priv->ex->orig_fprog);
+	fp = rcu_dereference_protected(lb_priv->fp,
+				       lockdep_is_held(&team->lock));
+	bpf_prog_destroy(fp);
+}
+
 static int lb_tx_method_get(struct team *team, struct team_gsetter_ctx *ctx)
 {
 	struct lb_priv *lb_priv = get_lb_priv(team);
@@ -639,6 +653,7 @@ static void lb_exit(struct team *team)
 
 	team_options_unregister(team, lb_options,
 				ARRAY_SIZE(lb_options));
+	lb_bpf_func_free(team);
 	cancel_delayed_work_sync(&lb_priv->ex->stats.refresh_dw);
 	free_percpu(lb_priv->pcpu_stats);
 	kfree(lb_priv->ex);