Thread (7 messages) 7 messages, 4 authors, 2025-10-16
STALE255d

[PATCH net v2] net: usb: lan78xx: fix use of improperly initialized dev->chipid in lan78xx_reset

From: I Viswanath <hidden>
Date: 2025-10-13 18:17:29
Also in: linux-kernel-mentees, linux-usb, lkml
Subsystem: networking drivers, the rest, usb lan78xx ethernet driver, usb networking drivers · Maintainers: Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Thangaraj Samynathan, Rengarajan Sundararajan

dev->chipid is used in lan78xx_init_mac_address before it's initialized:

lan78xx_reset() {
    lan78xx_init_mac_address()
        lan78xx_read_eeprom()
            lan78xx_read_raw_eeprom() <- dev->chipid is used here

    dev->chipid = ... <- dev->chipid is initialized correctly here
}

Reorder initialization so that dev->chipid is set before calling
lan78xx_init_mac_address().

Fixes: a0db7d10b76e ("lan78xx: Add to handle mux control per chip id")
Signed-off-by: I Viswanath <redacted>
---
v1:
Link: https://lore.kernel.org/netdev/20251001131409.155650-1-viswanathiyyappan@gmail.com/ (local)

v2:
- Add Fixes tag

 drivers/net/usb/lan78xx.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
index 42d35cc6b421..b4b086f86ed8 100644
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -3247,10 +3247,6 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 		}
 	} while (buf & HW_CFG_LRST_);
 
-	ret = lan78xx_init_mac_address(dev);
-	if (ret < 0)
-		return ret;
-
 	/* save DEVID for later usage */
 	ret = lan78xx_read_reg(dev, ID_REV, &buf);
 	if (ret < 0)
@@ -3259,6 +3255,10 @@ static int lan78xx_reset(struct lan78xx_net *dev)
 	dev->chipid = (buf & ID_REV_CHIP_ID_MASK_) >> 16;
 	dev->chiprev = buf & ID_REV_CHIP_REV_MASK_;
 
+	ret = lan78xx_init_mac_address(dev);
+	if (ret < 0)
+		return ret;
+
 	/* Respond to the IN token with a NAK */
 	ret = lan78xx_read_reg(dev, USB_CFG0, &buf);
 	if (ret < 0)
-- 
2.47.3
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