CVE-2025-68378 bpf: Fix stackmap overflow check in __bpf_get_stackid()

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix stackmap overflow check in bpfgetstackid Syzkaller reported a KASAN slab-out-of-bounds write in bpfgetstackid when copying stack trace data. The issue occurs when the perf trace contains more stack entries than the stack...