net: phylink: correctly validate returned PCS in phylink_inband_caps

In phylink_inband_caps(), the PCS returned by mac_select_pcs is only
checked if NULL but mac_select_pcs can also return an error pointer.

This can cause a kernel panic as phylink_pcs_inband_caps() only checks
if passed PCS is not NULL and directly dereference ops from the phylink_pcs
struct.

Use the IS_ERR_OR_NULL macro to address both case where the returned
PCS can be NULL or an error pointer and prevent a kernel panic.

Cc: stable@vger.kernel.org
Fixes: df874f9e52 ("net: phylink: add pcs_inband_caps() method")
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Link: https://patch.msgid.link/20260817213009.13924-1-ansuelsmth@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Christian Marangi 2026-08-17 23:30:03 +02:00 • committed by Jakub Kicinski
commit f2849b1fd0