CVE-2026-74321 btrfs: fix invalid pointer dereference in __btrfs_run_delayed_refs()

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix invalid pointer dereference in btrfsrundelayedrefs In the beginning of the loop, we try to obtain a locked delayed ref head, if 'lockedref' is currently NULL, by calling btrfsselectrefhead, which can return an error...