If no PHY device is found (e.g., for LAN7801 in fixed-link mode), lan78xx_phy_init() may proceed to dereference a NULL phydev pointer, leading to a crash. Update the logic to perform MAC configuration first, then check for the presence of a PHY. For the fixed-link case, set up the fixed link and return early, bypassing any code that assumes a valid phydev pointer. It is safe to move lan78xx_mac_prepare_for_phy() earlier because this function only uses information from dev->interface, which is configured by lan78xx_get_phy() beforehand. The function does not access phydev or any data set up by later steps. Reported-by: Dan Carpenter Signed-off-by: Oleksij Rempel --- drivers/net/usb/lan78xx.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index ae37cd235526..6e9dc30b50f9 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -2831,6 +2831,10 @@ static int lan78xx_phy_init(struct lan78xx_net *dev) if (ret < 0) return ret; + ret = lan78xx_mac_prepare_for_phy(dev); + if (ret < 0) + goto phylink_uninit; + /* If no PHY is found, set up a fixed link. It is very specific to * the LAN7801 and is used in special cases like EVB-KSZ9897-1 where * LAN7801 acts as a USB-to-Ethernet interface to a switch without @@ -2840,11 +2844,12 @@ static int lan78xx_phy_init(struct lan78xx_net *dev) ret = lan78xx_set_fixed_link(dev); if (ret < 0) goto phylink_uninit; - } - ret = lan78xx_mac_prepare_for_phy(dev); - if (ret < 0) - goto phylink_uninit; + /* No PHY found, so set up a fixed link and return early. + * No need to configure PHY IRQ or attach to phylink. + */ + return 0; + } /* if phyirq is not set, use polling mode in phylib */ if (dev->domain_data.phyirq > 0) -- 2.39.5