[PATCH] net: dsa: felix: Add NULL check for outer_tagging_rule()

[Wentao Liang]

In felix_update_tag_8021q_rx_rules(), the return value of
ocelot_vcap_block_find_filter_by_id() is not checked, which could
lead to a NULL pointer dereference if the filter is not found.

Add the necessary check and use `continue` to skip the current CPU
port if the filter is not found, ensuring that all CPU ports are
processed.

Fixes: f1288fd7293b ("net: dsa: felix: fix VLAN tag loss on CPU reception with ocelot-8021q")
Cc: stable@xxxxxxxxxxxxxxx # 6.11+
Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
---
 drivers/net/dsa/ocelot/felix.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 3aa9c997018a..10ad43108b88 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c
@@ -348,6 +348,8 @@ static int felix_update_tag_8021q_rx_rules(struct dsa_switch *ds, int port,
 
 		outer_tagging_rule = ocelot_vcap_block_find_filter_by_id(block_vcap_es0,
 									 cookie, false);
+		if (!outer_tagging_rule)
+			continue;
 
 		felix_update_tag_8021q_rx_rule(outer_tagging_rule, vlan_filtering);
 
-- 
2.42.0.windows.2