CVE-2021-47567

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> powerpc/32: Fix hardlockup on vmap stack overflow<br /> <br /> Since the commit c118c7303ad5 ("powerpc/32: Fix vmap stack - Do not<br /> activate MMU before reading task struct") a vmap stack overflow<br /> results in a hard lockup. This is because emergency_ctx is still<br /> addressed with its virtual address allthough data MMU is not active<br /> anymore at that time.<br /> <br /> Fix it by using a physical address instead.