CVE-2025-38696 MIPS: Don't crash in stack_top() for tasks without ABI or vDSO

In the Linux kernel, the following vulnerability has been resolved: MIPS: Don't crash in stacktop for tasks without ABI or vDSO Not all tasks have an ABI associated or vDSO mapped, for example kthreads never do. If such a task ever ends up calling stacktop, it will derefence the NULL ABI pointer...