From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Sat, 23 May 2020 17:40:25 +0200
Subject: ethtool: propagate get_coalesce return value
Patch-mainline: v5.8-rc1
Git-commit: 316107119f473e764cf5e50437333c8b83bec0da
References: bsc#1176447

get_coalesce returns 0 or ERRNO, but the return value isn't checked.
The returned coalesce data may be invalid if an ERRNO is set,
therefore better check and propagate the return value.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Kubecek <mkubecek@suse.cz>

---
 net/ethtool/ioctl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -1503,11 +1503,14 @@ static noinline_for_stack int ethtool_get_coalesce(struct net_device *dev,
 						   void __user *useraddr)
 {
 	struct ethtool_coalesce coalesce = { .cmd = ETHTOOL_GCOALESCE };
+	int ret;
 
 	if (!dev->ethtool_ops->get_coalesce)
 		return -EOPNOTSUPP;
 
-	dev->ethtool_ops->get_coalesce(dev, &coalesce);
+	ret = dev->ethtool_ops->get_coalesce(dev, &coalesce);
+	if (ret)
+		return ret;
 
 	if (copy_to_user(useraddr, &coalesce, sizeof(coalesce)))
 		return -EFAULT;