[PATCH 6.12 120/337] net: dsa: mt7530: check bus->read() errors in the MDIO regmap backend
Greg Kroah-Hartman <[email protected]>
| Newsgroups | dev.linux.lists.patches,org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Golle <[email protected]> [ Upstream commit b4ce102b2cd88424c5860fbbb20b9eb343a93bf4 ] bus->read() returns a negative errno on failure, but mt7530_regmap_read() assigns it to a u16, truncating e.g. -ETIMEDOUT into 0xff92, and returns success. The garbage word is then consumed as register data, and read-modify-write cycles write it back to the switch. Check both reads and propagate their errors. The same defect existed in mt7530_mii_read() since the driver was introduced and moved into the regmap backend unchanged. Fixes: b8f126a8d543 ("net-next: dsa: add dsa support for Mediatek MT7530 switch") Signed-off-by: Daniel Golle <[email protected]> Reviewed-by: Andrew Lunn <[email protected]> Link: https://patch.msgid.link/3c628e48276c2e5522c8795a6be60d11c7a76a7d.1785213071.git.daniel@makrotopia.org Signed-off-by: Jakub Kicinski <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- drivers/net/dsa/mt7530-mdio.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/net/dsa/mt7530-mdio.c b/drivers/net/dsa/mt7530-mdio.c index 51df42ccdbe62..e19b46449ffe6 100644 --- a/drivers/net/dsa/mt7530-mdio.c +++ b/drivers/net/dsa/mt7530-mdio.c @@ -55,8 +55,15 @@ mt7530_regmap_read(void *context, unsigned int reg, unsigned int *val) if (ret < 0) return ret; - lo = bus->read(bus, priv->mdiodev->addr, r); - hi = bus->read(bus, priv->mdiodev->addr, 0x10); + ret = bus->read(bus, priv->mdiodev->addr, r); + if (ret < 0) + return ret; + lo = ret; + + ret = bus->read(bus, priv->mdiodev->addr, 0x10); + if (ret < 0) + return ret; + hi = ret; *val = (hi << 16) | (lo & 0xffff); -- 2.53.0