[PATCH net v2] ethtool: netlink: Add missing ethnl_ops_begin/complete

[Ludvig Pärsson]

Accessing an ethernet device that is powered off or clock gated might
cause the CPU to hang. Add ethnl_ops_begin/complete in
ethnl_set_features() to protect against this.

Fixes: 0980bfcd6954 ("ethtool: set netdev features with FEATURES_SET request")
Signed-off-by: Ludvig Pärsson <ludvig.parsson@xxxxxxxx>
---
Changes in v2:
- Add Fixes tag.
- Link to v1: https://lore.kernel.org/r/20240108-etht2-v1-1-beab95e80f7e@xxxxxxxx
---
 net/ethtool/features.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/ethtool/features.c b/net/ethtool/features.c
index a79af8c25a07..b6cb101d7f19 100644
--- a/net/ethtool/features.c
+++ b/net/ethtool/features.c
@@ -234,17 +234,20 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info)
 	dev = req_info.dev;
 
 	rtnl_lock();
+	ret = ethnl_ops_begin(dev);
+	if (ret < 0)
+		goto out_rtnl;
 	ethnl_features_to_bitmap(old_active, dev->features);
 	ethnl_features_to_bitmap(old_wanted, dev->wanted_features);
 	ret = ethnl_parse_bitset(req_wanted, req_mask, NETDEV_FEATURE_COUNT,
 				 tb[ETHTOOL_A_FEATURES_WANTED],
 				 netdev_features_strings, info->extack);
 	if (ret < 0)
-		goto out_rtnl;
+		goto out_ops;
 	if (ethnl_bitmap_to_features(req_mask) & ~NETIF_F_ETHTOOL_BITS) {
 		GENL_SET_ERR_MSG(info, "attempt to change non-ethtool features");
 		ret = -EINVAL;
-		goto out_rtnl;
+		goto out_ops;
 	}
 
 	/* set req_wanted bits not in req_mask from old_wanted */
@@ -281,6 +284,8 @@ int ethnl_set_features(struct sk_buff *skb, struct genl_info *info)
 	if (mod)
 		netdev_features_change(dev);
 
+out_ops:
+	ethnl_ops_complete(dev);
 out_rtnl:
 	rtnl_unlock();
 	ethnl_parse_header_dev_put(&req_info);

---
base-commit: 0dd3ee31125508cd67f7e7172247f05b7fd1753a
change-id: 20240108-etht2-2b2454e837e7

Best regards,
-- 
Ludvig Pärsson <ludvig.parsson@xxxxxxxx>