[PATCH net-next v2 2/5] ethtool: hold a reference to the netdevice around devlink compat

[Jakub Kicinski <jakub.kicinski@netronome.com>]

When calling into devlink compat code make sure we have a reference
on the netdevice on which the operation was invoked.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
 net/core/ethtool.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 1320e8dce559..6832476dfcaf 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -805,11 +805,14 @@ static noinline_for_stack int ethtool_get_drvinfo(struct net_device *dev,
 	if (ops->get_eeprom_len)
 		info.eedump_len = ops->get_eeprom_len(dev);
 
-	rtnl_unlock();
-	if (!info.fw_version[0])
+	if (!info.fw_version[0]) {
+		dev_hold(dev);
+		rtnl_unlock();
 		devlink_compat_running_version(dev, info.fw_version,
 					       sizeof(info.fw_version));
-	rtnl_lock();
+		rtnl_lock();
+		dev_put(dev);
+	}
 
 	if (copy_to_user(useraddr, &info, sizeof(info)))
 		return -EFAULT;
@@ -2043,9 +2046,11 @@ static noinline_for_stack int ethtool_flash_device(struct net_device *dev,
 	if (!dev->ethtool_ops->flash_device) {
 		int ret;
 
+		dev_hold(dev);
 		rtnl_unlock();
 		ret = devlink_compat_flash_update(dev, efl.data);
 		rtnl_lock();
+		dev_put(dev);
 
 		return ret;
 	}
-- 
2.19.2