1.7 KiB
CVE-2021-47187
Description
In the Linux kernel, the following vulnerability has been resolved:arm64: dts: qcom: msm8998: Fix CPU/L2 idle state latency and residencyThe entry/exit latency and minimum residency in state for the idlestates of MSM8998 were ..bad: first of all, for all of them thetimings were written for CPU sleep but the min-residency-us paramwas miscalculated (supposedly, while porting this from downstream);Then, the power collapse states are setting PC on both the CPUcluster and the L2 cache, which have different timings: in thespecific case of L2 the times are higher so these ones should betaken into account instead of the CPU ones.This parameter misconfiguration was not giving particular issuesbecause on MSM8998 there was no CPU scaling at all, so cluster/L2power collapse was rarely (if ever) hit.When CPU scaling is enabled, though, the wrong timings will produceSoC unstability shown to the user as random, apparently error-less,sudden reboots and/or lockups.This set of parameters are stabilizing the SoC when CPU scaling isON and when power collapse is frequently hit.
POC
Reference
No PoCs from references.