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Vulnerability CVE-2021-47187
Published: 2024-04-10
| 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 parameters are stabilizing the SoC when CPU scaling is
ON and when power collapse is frequently hit. |
References: |
https://git.kernel.org/stable/c/a14d7038ea201c5526375becfc43b9ba281b1e82
https://git.kernel.org/stable/c/e52fecdd0c142b95c720683885b06ee3f0e065c8
https://git.kernel.org/stable/c/118c826ef8b43efe0fda8faf419673707ee8c5e5
https://git.kernel.org/stable/c/3f1dcaff642e75c1d2ad03f783fa8a3b1f56dd50
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