[PATCH net] net: phy: Fix possible NULL pointer dereference issues caused by phy_attached_info_irq

[Kunwu Chan]

kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.

Fixes: e27f178793de ("net: phy: Added IRQ print to phylink_bringup_phy()")
Signed-off-by: Kunwu Chan <chentao@xxxxxxxxxx>
---
 drivers/net/phy/phy_device.c | 3 +++
 drivers/net/phy/phylink.c    | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c
index 3611ea64875e..10fa99d957c0 100644
--- a/drivers/net/phy/phy_device.c
+++ b/drivers/net/phy/phy_device.c
@@ -1299,6 +1299,9 @@ void phy_attached_print(struct phy_device *phydev, const char *fmt, ...)
 	const char *unbound = phydev->drv ? "" : "[unbound] ";
 	char *irq_str = phy_attached_info_irq(phydev);
 
+	if (!irq_str)
+		return;
+
 	if (!fmt) {
 		phydev_info(phydev, ATTACHED_FMT "\n", unbound,
 			    phydev_name(phydev), irq_str);
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index ed0b4ccaa6a6..db0a545c9468 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -1884,6 +1884,8 @@ static int phylink_bringup_phy(struct phylink *pl, struct phy_device *phy,
 	phy->phy_link_change = phylink_phy_change;
 
 	irq_str = phy_attached_info_irq(phy);
+	if (!irq_str)
+		return -ENOMEM;
 	phylink_info(pl,
 		     "PHY [%s] driver [%s] (irq=%s)\n",
 		     dev_name(&phy->mdio.dev), phy->drv->name, irq_str);
-- 
2.39.2