[PATCH net] net: dsa: mv88e6xxx: Avoid uninitialized value on MDIO read error
From: Ruoyu Wang <hidden>
Date: 2026-08-14 13:40:13
Also in:
lkml
Subsystem:
marvell 88e6xxx ethernet switch fabric driver, networking drivers, networking [dsa], the rest · Maintainers:
Andrew Lunn, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds
An SMI timeout or PPU access failure can make a Clause 22 PHY read
return without initializing its output value. When reading MII_PHYSID2,
mv88e6xxx_mdio_read() still passes that value through the internal PHY
model-number workaround before returning the error, causing an
uninitialized stack read.
Run the workaround only after a successful PHY read. This preserves the
original error and leaves successful PHY ID reads unchanged.
This issue was found by a static analysis checker and confirmed by
manual source review.
Fixes: da9f33018e2c ("net: dsa: mv88e6xxx: Workaround missing PHY ID on mv88e6390")
Signed-off-by: Ruoyu Wang <redacted>
---
drivers/net/dsa/mv88e6xxx/chip.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/dsa/mv88e6xxx/chip.c b/drivers/net/dsa/mv88e6xxx/chip.c
index 80b877c74513d..e71707ce71cbc 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.c
+++ b/drivers/net/dsa/mv88e6xxx/chip.c@@ -3770,7 +3770,7 @@ static int mv88e6xxx_mdio_read(struct mii_bus *bus, int phy, int reg) mv88e6xxx_reg_unlock(chip); /* Some internal PHYs don't have a model number. */ - if (reg == MII_PHYSID2 && !(val & 0x3f0) && + if (!err && reg == MII_PHYSID2 && !(val & 0x3f0) && chip->info->family < ARRAY_SIZE(family_prod_id_table)) { prod_id = family_prod_id_table[chip->info->family]; if (prod_id)
--
2.51.0