[PATCH] net: dsa: bcm_sf2_cfp: fix an incorrect NULL check on list iterator

[PATCH] net: dsa: bcm_sf2_cfp: fix an incorrect NULL check on list iterator

[Xiaomeng Tong]

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.

Fixes: ae7a5aff783c7 ("net: dsa: bcm_sf2: Keep copy of inserted rules")
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
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

Re: [PATCH] net: dsa: bcm_sf2_cfp: fix an incorrect NULL check on list iterator

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 28 Mar 2022 11:24:31 +0800 you wrote:
> 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.
> 
> [...]

Here is the summary with links:
  - net: dsa: bcm_sf2_cfp: fix an incorrect NULL check on list iterator
    https://git.kernel.org/netdev/net/c/6da69b1da130

You are awesome, thank you!
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