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From:   Xiaomeng Tong <xiam0nd.tong@gmail.com>
To:     andrew@lunn.ch
Cc:     vivien.didelot@gmail.com, olteanv@gmail.com, davem@davemloft.net,
        kuba@kernel.org, pabeni@redhat.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Xiaomeng Tong <xiam0nd.tong@gmail.com>, stable@vger.kernel.org
Subject: [PATCH] dsa: bcm_sf2_cfp: fix an incorrect NULL check on list iterator
Date:   Sun, 27 Mar 2022 13:55:47 +0800
Message-Id: <20220327055547.3938-1-xiam0nd.tong@gmail.com>
Precedence: bulk

The bug is here:
	return rule;

The list iterator value 'rule' will *always* be set and non-NULL
by list_for_each_entry(), so it is incorrect to assume that the
iterator value will be NULL if the list is empty or no element
is found.

To fix the bug, return 'rule' when found, otherwise return NULL.

Cc: stable@vger.kernel.org
Fixes: ae7a5aff783c7 ("net: dsa: bcm_sf2: Keep copy of inserted rules")
Signed-off-by: Xiaomeng Tong <xiam0nd.tong@gmail.com>
---
 drivers/net/dsa/bcm_sf2_cfp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/bcm_sf2_cfp.c b/drivers/net/dsa/bcm_sf2_cfp.c
index a7e2fcf2df2c..edbe5e7f1cb6 100644
--- a/drivers/net/dsa/bcm_sf2_cfp.c
+++ b/drivers/net/dsa/bcm_sf2_cfp.c
@@ -567,14 +567,14 @@ static void bcm_sf2_cfp_slice_ipv6(struct bcm_sf2_priv *priv,
 static struct cfp_rule *bcm_sf2_cfp_rule_find(struct bcm_sf2_priv *priv,
 					      int port, u32 location)
 {
-	struct cfp_rule *rule = NULL;
+	struct cfp_rule *rule;
 
 	list_for_each_entry(rule, &priv->cfp.rules_list, next) {
 		if (rule->port == port && rule->fs.location == location)
-			break;
+			return rule;
 	}
 
-	return rule;
+	return NULL;
 }
 
 static int bcm_sf2_cfp_rule_cmp(struct bcm_sf2_priv *priv, int port,
-- 
2.17.1