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net: phy: microchip_t1: fix NULL pointer dereference in lan887x_phy_init()

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The issue was discovered via smatch static analyzer:

  make CHECK="smatch -p=kernel"  C=2  drivers/net/phy/microchip_t1.o
    CHECK   scripts/mod/empty.c
    DESCEND objtool
    CHECK   drivers/net/phy/microchip_t1.c
  drivers/net/phy/microchip_t1.c:1295 lan887x_phy_init() warn: 'priv->clock' can also be NULL

mchp_rds_ptp_probe() returns NULL when CONFIG_MICROCHIP_PHY_RDS_PTP or
CONFIG_PTP_1588_CLOCK is disabled. However, lan887x_phy_init() only checks
for an error pointer before using the returned clock to configure the
periodic output pin, which can result in a NULL pointer dereference.

Handle the NULL return as PTP being unavailable and skip the event pin
configuration in that case. Smatch no longer reports the NULL dereference
warning after the change.

Cc: stable+noautosel@kernel.org # untested fix to unlikely driver error path
Reviewed-by: Divya Koppera <Divya.Koppera@microchip.com>
Signed-off-by: Henry Hu <huhai@kylinos.cn>
Link: https://patch.msgid.link/20260903113046.163630-1-15815827059@163.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Henry Hu 2026-09-03 19:30:46 +08:00 committed by Jakub Kicinski
parent 6f157f39d1
commit a4050ce7e4
1 changed files with 9 additions and 7 deletions
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16
drivers/net/phy/microchip_t1.c
View File

@ -1285,14 +1285,16 @@ static int lan887x_phy_init(struct phy_device *phydev)
if (IS_ERR(priv->clock))
return PTR_ERR(priv->clock);
/* Enable pin mux for EVT */
phy_modify_mmd(phydev, MDIO_MMD_VEND1,
LAN887X_MX_CHIP_TOP_REG_CONTROL1,
LAN887X_MX_CHIP_TOP_REG_CONTROL1_EVT_EN,
LAN887X_MX_CHIP_TOP_REG_CONTROL1_EVT_EN);
if (priv->clock) {
/* Enable pin mux for EVT */
phy_modify_mmd(phydev, MDIO_MMD_VEND1,
LAN887X_MX_CHIP_TOP_REG_CONTROL1,
LAN887X_MX_CHIP_TOP_REG_CONTROL1_EVT_EN,
LAN887X_MX_CHIP_TOP_REG_CONTROL1_EVT_EN);
/* Initialize pin numbers specific to PEROUT */
priv->clock->event_pin = 3;
/* Initialize pin numbers specific to PEROUT */
priv->clock->event_pin = 3;
}
priv->init_done = true;
}