Linux Kernel SDM845/850 Devices Page Table Walker Cache Coherency Vulnerability

A vulnerability in the Linux kernel has been addressed, specifically related to the page table walker cache coherency on SDM845/850 devices. This issue has caused lock-ups and resets on some devices, such as the Lenovo Yoga C630, while others, like the Dragonboard 845c, function properly. The problem appears to stem from a firmware development oversight, where a necessary adjustment in the hypervisor stack was only made after the initial software release, which typically serves as a product baseline. The vulnerability's resolution involved reverting a previous change that had introduced uncertainty around crash causes.

Impact

The lack of proper cache coherency can lead to system lock-ups and resets on affected devices.