CVE-2025-21867 bpf, test_run: Fix use-after-free issue in eth_skb_pkt_type()

In the Linux kernel, the following vulnerability has been resolved: bpf, testrun: Fix use-after-free issue in ethskbpkttype KMSAN reported a use-after-free issue in ethskbpkttype1. The cause of the issue was that ethskbpkttype accessed skb's data that didn't contain an Ethernet header. This occur...