From d77ab053fb2f97ff366118d4dbffd8fe48168541 Mon Sep 17 00:00:00 2001 From: Javier Carrasco Date: Sun, 25 Feb 2024 00:20:06 +0100 Subject: [PATCH] net: usb: dm9601: fix wrong return value in dm9601_mdio_read [ Upstream commit c68b2c9eba38ec3f60f4894b189090febf4d8d22 ] The MII code does not check the return value of mdio_read (among others), and therefore no error code should be sent. A previous fix to the use of an uninitialized variable propagates negative error codes, that might lead to wrong operations by the MII library. An example of such issues is the use of mii_nway_restart by the dm9601 driver. The mii_nway_restart function does not check the value returned by mdio_read, which in this case might be a negative number which could contain the exact bit the function checks (BMCR_ANENABLE = 0x1000). Return zero in case of error, as it is common practice in users of mdio_read to avoid wrong uses of the return value. Fixes: 8f8abb863fa5 ("net: usb: dm9601: fix uninitialized variable use in dm9601_mdio_read") Signed-off-by: Javier Carrasco Reviewed-by: Simon Horman Reviewed-by: Peter Korsgaard Link: https://lore.kernel.org/r/20240225-dm9601_ret_err-v1-1-02c1d959ea59@gmail.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- drivers/net/usb/dm9601.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/usb/dm9601.c b/drivers/net/usb/dm9601.c index 99ec1d4a972d..8b6d6a1b3c2e 100644 --- a/drivers/net/usb/dm9601.c +++ b/drivers/net/usb/dm9601.c @@ -232,7 +232,7 @@ static int dm9601_mdio_read(struct net_device *netdev, int phy_id, int loc) err = dm_read_shared_word(dev, 1, loc, &res); if (err < 0) { netdev_err(dev->net, "MDIO read error: %d\n", err); - return err; + return 0; } netdev_dbg(dev->net,