[PATCH] net: phy: only remove owned topology entries

[PATCH] net: phy: only remove owned topology entries

[Jiale Yao]

phy_link_topo_add_phy() can fail to insert a PHY when its saved index is
already occupied.  Its caller may subsequently run the normal detach
path.  phy_link_topo_del_phy() then unconditionally removes the entry at
that index, including its ports, even though the entry belongs to a
different PHY.

Look up the topology entry first and only remove the PHY and its ports
when the entry belongs to the PHY being detached.

Fixes: 384968786909 ("net: phy: Introduce ethernet link topology representation")
Cc: stable@vger.kernel.org
Signed-off-by: Jiale Yao <yaojiale02@163.com>
---
 drivers/net/phy/phy_link_topology.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/phy/phy_link_topology.c b/drivers/net/phy/phy_link_topology.c
index 214ccce23cf6..175eef44cf54 100644
--- a/drivers/net/phy/phy_link_topology.c
+++ b/drivers/net/phy/phy_link_topology.c
@@ -185,6 +185,10 @@ void phy_link_topo_del_phy(struct net_device *dev,
 	if (!topo)
 		return;
 
+	pdn = xa_load(&topo->phys, phy->phyindex);
+	if (!pdn || pdn->phy != phy)
+		return;
+
 	list_for_each_entry(port, &phy->ports, head)
 		phy_link_topo_del_port(dev, port);
 
-- 
2.34.1

Re: [PATCH] net: phy: only remove owned topology entries

[netdev-bot+sinfo]

Hi!

This is an automated message. This series looks like a fix, but its
commit messages seem to be missing some information:

 - How the issue was discovered, e.g. hit in production, hit during
   development, syzbot report, manual code inspection, LLM or static
   analysis tool scan.

 - Whether the issue was actually triggered, or is only theoretical
   (e.g. found by code inspection). If it was triggered please include
   the symptoms, like the stack trace or error messages.

Please do not repost the series just to address the above. Instead,
reply to this email with the missing information, so that reviewers
can take it into account. If the series needs another revision for
other reasons, please include the information in the commit messages
then.

The evaluation is done by an LLM so it may be wrong, if you think
that is the case please reply and explain.

Re: [PATCH] net: phy: only remove owned topology entries

[Maxime Chevallier]

On 10/28/26 06:03, Jiale Yao wrote:
> phy_link_topo_add_phy() can fail to insert a PHY when its saved index is
> already occupied.

It's unclear to me how this can happen in real life...

>  Its caller may subsequently run the normal detach
> path.  phy_link_topo_del_phy() then unconditionally removes the entry at
> that index, including its ports, even though the entry belongs to a
> different PHY.
> 
> Look up the topology entry first and only remove the PHY and its ports
> when the entry belongs to the PHY being detached.

Maxime

Re: [PATCH] net: phy: only remove owned topology entries

[Andrew Lunn]

On Wed, Oct 28, 2026 at 01:03:12PM +0800, Jiale Yao wrote:
> phy_link_topo_add_phy() can fail to insert a PHY when its saved index is
> already occupied.

How did you get into this state? It indicates there is another bug
somewhere which needs fixing. Fixing that bug is much more important.

	  Andrew