On Tue, Sep 10, 2024 at 7:20 PM Maxime Chevallier
[off-list ref] wrote:

Hello Eric,

On Tue, 10 Sep 2024 18:41:03 +0200
Eric Dumazet [off-list ref] wrote:

quoted

quoted

+int ethnl_phy_doit(struct sk_buff *skb, struct genl_info *info)
+{
+       struct phy_req_info req_info = {};
+       struct nlattr **tb = info->attrs;
+       struct sk_buff *rskb;
+       void *reply_payload;
+       int reply_len;
+       int ret;
+
+       ret = ethnl_parse_header_dev_get(&req_info.base,
+                                        tb[ETHTOOL_A_PHY_HEADER],
+                                        genl_info_net(info), info->extack,
+                                        true);
+       if (ret < 0)
+               return ret;
+
+       rtnl_lock();
+
+       ret = ethnl_phy_parse_request(&req_info.base, tb, info->extack);
+       if (ret < 0)
+               goto err_unlock_rtnl;
+
+       /* No PHY, return early */

I got a syzbot report here.

I seem to have missed the report, sorry about that.

quoted

Should we fix this with :

diff --git a/net/ethtool/phy.c b/net/ethtool/phy.c
index 560dd039c6625ac0925a0f28c14ce77cf768b6a5..4ef7c6e32d1087dc71acb467f9cd2ab8faf4dc39

100644

--- a/net/ethtool/phy.c
+++ b/net/ethtool/phy.c

@@ -164,7 +164,7 @@ int ethnl_phy_doit(struct sk_buff *skb, struct

genl_info *info)
                goto err_unlock_rtnl;

        /* No PHY, return early */
-       if (!req_info.pdn->phy)
+       if (!req_info.pdn)
                goto err_unlock_rtnl;

        ret = ethnl_phy_reply_size(&req_info.base, info->extack);

Indeed that's the correct fix. Should I send it ? ( including
suggested-by/reported-by )

Yes please, go ahead.

Thanks,

Maxime