CVE-2021-47187

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

arm64: dts: qcom: msm8998: Fix CPU/L2 idle state latency and residency

The entry/exit latency and minimum residency in state for the idle

states of MSM8998 were ..bad: first of all, for all of them the

timings were written for CPU sleep but the min-residency-us param

was miscalculated (supposedly, while porting this from downstream);

Then, the power collapse states are setting PC on both the CPU

cluster *and* the L2 cache, which have different timings: in the

specific case of L2 the times are higher so these ones should be

taken into account instead of the CPU ones.

This parameter misconfiguration was not giving particular issues

because on MSM8998 there was no CPU scaling at all, so cluster/L2

power collapse was rarely (if ever) hit.

When CPU scaling is enabled, though, the wrong timings will produce

SoC unstability shown to the user as random, apparently error-less,

sudden reboots and/or lockups.

This set of para

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References