dev: Acquire netdev_rename_lock before restoring dev->name in dev_change_name().

The cited commit forgot to add netdev_rename_lock in one of the
error paths in dev_change_name().

Let's hold netdev_rename_lock before restoring the old dev->name.

Fixes: 0840556e5a3a ("net: Protect dev->name by seqlock.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250115095545.52709-2-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index 782ae3f..cb6da0c 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1389,7 +1389,9 @@ int dev_change_name(struct net_device *dev, const char *newname)
 rollback:
        ret = device_rename(&dev->dev, dev->name);
        if (ret) {
+               write_seqlock_bh(&netdev_rename_lock);
                memcpy(dev->name, oldname, IFNAMSIZ);
+               write_sequnlock_bh(&netdev_rename_lock);
                WRITE_ONCE(dev->name_assign_type, old_assign_type);
                up_write(&devnet_rename_sem);
                return ret;