um: init cpu_tasks[] earlier

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: um: init cpu_tasks[] earlier This is currently done in uml_finishsetup(), but e.g. with KCOV enabled we'll crash because some init code can call into e.g. memparse(), which has coverage annotations, and then the checks in check_kcov_mode() crash because current is NULL. Simply initialize the cpu_tasks[] array statically, which fixes the crash. For the later SMP work, it seems to have not really caused any problems yet, but initialize all of the entries anyway.

References

• https://git.kernel.org/stable/c/dbbf6d47130674640cd12a0781a0fb2a575d0e44
• https://git.kernel.org/stable/c/7b5d4416964c07c902163822a30a622111172b01