fix an unreleased lock in out_dev_put path and substitute
both labels (out_rtnl and out_dev_put) for a simpler out.

Reported-by: syzbot+c641161e97237326ea74@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c641161e97237326ea74
Fixes: 3688ff3077d3 ("net: ethtool: cable-test: Target the command to the requested PHY")
Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
---
 net/ethtool/cabletest.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/net/ethtool/cabletest.c b/net/ethtool/cabletest.c
index 01db8f394869..c1f0510eb465 100644
--- a/net/ethtool/cabletest.c
+++ b/net/ethtool/cabletest.c
@@ -77,18 +77,18 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
 				      info->extack);
 	if (IS_ERR_OR_NULL(phydev)) {
 		ret = -EOPNOTSUPP;
-		goto out_dev_put;
+		goto out;
 	}
 
 	ops = ethtool_phy_ops;
 	if (!ops || !ops->start_cable_test) {
 		ret = -EOPNOTSUPP;
-		goto out_rtnl;
+		goto out;
 	}
 
 	ret = ethnl_ops_begin(dev);
 	if (ret < 0)
-		goto out_rtnl;
+		goto out;
 
 	ret = ops->start_cable_test(phydev, info->extack);
 
@@ -97,9 +97,8 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
 	if (!ret)
 		ethnl_cable_test_started(phydev, ETHTOOL_MSG_CABLE_TEST_NTF);
 
-out_rtnl:
+out:
 	rtnl_unlock();
-out_dev_put:
 	ethnl_parse_header_dev_put(&req_info);
 	return ret;
 }
-- 
2.43.0

On Mon, Aug 26, 2024 at 09:14:15AM -0300, Diogo Jahchan Koike wrote:
> fix an unreleased lock in out_dev_put path and substitute
> both labels (out_rtnl and out_dev_put) for a simpler out.

Hi Diogo

We try to keep fixes simple. I would of changed the out_dev_put to
out_rtnl, and then removed the unused out_dev_put. That makes the
change smaller, more obviously correct.

As far as i can see, 3688ff3077d3 is only in net-next, not an -rc
kernel. As such, we want this patch added to net-next. You indicate
this in the patch Subject: [path net-next v2].

Thanks

    Andrew

---
pw-bot: cr

fix an unreleased lock in out_dev_put path by removing the (now)
unnecessary path.

Reported-by: syzbot+c641161e97237326ea74@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=c641161e97237326ea74
Fixes: 3688ff3077d3 ("net: ethtool: cable-test: Target the command to the requested PHY")
Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>
---
 net/ethtool/cabletest.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/ethtool/cabletest.c b/net/ethtool/cabletest.c
index 01db8f394869..8c5aa63cb1aa 100644
--- a/net/ethtool/cabletest.c
+++ b/net/ethtool/cabletest.c
@@ -77,7 +77,7 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
 				      info->extack);
 	if (IS_ERR_OR_NULL(phydev)) {
 		ret = -EOPNOTSUPP;
-		goto out_dev_put;
+		goto out_rtnl;
 	}
 
 	ops = ethtool_phy_ops;
@@ -99,7 +99,6 @@ int ethnl_act_cable_test(struct sk_buff *skb, struct genl_info *info)
 
 out_rtnl:
 	rtnl_unlock();
-out_dev_put:
 	ethnl_parse_header_dev_put(&req_info);
 	return ret;
 }
-- 
2.43.0

Hi,

Thanks for addressing this, I was unavailable in the past hours to
quicky respond to the issue so your help is welcome :)

On Mon, 26 Aug 2024 10:45:46 -0300
Diogo Jahchan Koike <djahchankoike@gmail.com> wrote:

> fix an unreleased lock in out_dev_put path by removing the (now)
> unnecessary path.
> 
> Reported-by: syzbot+c641161e97237326ea74@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=c641161e97237326ea74
> Fixes: 3688ff3077d3 ("net: ethtool: cable-test: Target the command to the requested PHY")
> Signed-off-by: Diogo Jahchan Koike <djahchankoike@gmail.com>

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

Thanks,

Maxime