It could lead to error happen because the variable res is not updated if
the call to sr_share_read_word returns an error. In this particular case
error code was returned and res stayed uninitialized. Same issue also
applies to sr_read_reg.
This can be avoided by checking the return value of sr_share_read_word
and sr_read_reg, and propagating the error if the read operation failed.
Found by code review.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: c9b37458e956 ("USB2NET : SR9700 : One chip USB 1.1 USB2NET SR9700Device Driver Support")
Signed-off-by: Ma Ke <make24@xxxxxxxxxxx>
---
Changes in v4:
- added a check for sr_read_reg() as suggestions.
Changes in v3:
- added Cc stable line as suggestions.
Changes in v2:
- modified the subject as suggestions.
---
drivers/net/usb/sr9700.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/net/usb/sr9700.c b/drivers/net/usb/sr9700.c
index 0a662e42ed96..cb7d2f798fb4 100644
--- a/drivers/net/usb/sr9700.c
+++ b/drivers/net/usb/sr9700.c
@@ -179,6 +179,7 @@ static int sr_mdio_read(struct net_device *netdev, int phy_id, int loc)
struct usbnet *dev = netdev_priv(netdev);
__le16 res;
int rc = 0;
+ int err;
if (phy_id) {
netdev_dbg(netdev, "Only internal phy supported\n");
@@ -189,11 +190,17 @@ static int sr_mdio_read(struct net_device *netdev, int phy_id, int loc)
if (loc == MII_BMSR) {
u8 value;
- sr_read_reg(dev, SR_NSR, &value);
+ err = sr_read_reg(dev, SR_NSR, &value);
+ if (err < 0)
+ return err;
+
if (value & NSR_LINKST)
rc = 1;
}
- sr_share_read_word(dev, 1, loc, &res);
+ err = sr_share_read_word(dev, 1, loc, &res);
+ if (err < 0)
+ return err;
+
if (rc == 1)
res = le16_to_cpu(res) | BMSR_LSTATUS;
else
--
2.25.1
