On Thu, Oct 09, 2025 at 11:00:09AM +0530, Bhanu Seshu Kumar Valluri wrote:

The function lan78xx_write_raw_eeprom failed to properly propagate EEPROM
write timeout errors (-ETIMEDOUT). In the timeout  fallthrough path, it first
attempted to restore the pin configuration for LED outputs and then
returned only the status of that restore operation, discarding the
original timeout error saved in ret.

As a result, callers could mistakenly treat EEPROM write operation as
successful even though the EEPROM write had actually timed out with no
or partial data write.

To fix this, handle errors in restoring the LED pin configuration separately.
If the restore succeeds, return any prior EEPROM write timeout error saved
in ret to the caller.

Suggested-by: Oleksij Rempel <o.rempel@pengutronix.de>
Fixes: 8b1b2ca83b20 ("net: usb: lan78xx: Improve error handling in EEPROM and OTP operations")
cc: stable@vger.kernel.org
Signed-off-by: Bhanu Seshu Kumar Valluri <redacted>
---
 Note:
 The patch is compiled and tested using EVB-LAN7800LC.
 The patch was suggested by Oleksij Rempel while reviewing a fix to a bug
 found by syzbot earlier.
 The review mail chain where this fix was suggested is given below.
 https://lore.kernel.org/all/aNzojoXK-m1Tn6Lc@pengutronix.de/ (local)

 ChangeLog:
 v1->v2:
  Added cc:stable tag as asked during v1 review.
  V1 Link : https://lore.kernel.org/all/20251004040722.82882-1-bhanuseshukumar@gmail.com/ (local)

Thanks,

This patch seems consistent with the discussion at the link under Note.
I believe it addresses the review of v1.
And that the Fixes tag corresponds to the commit that introduced this problem.

Reviewed-by: Simon Horman <horms@kernel.org>