| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47187: arm64: dts: qcom: msm8998: Fix CPU/L2 idle state latency and residency |
| |
| 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. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47187 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.3 with commit c3083c80b52c4e29b65ed838d2e66a91b13a3152 and fixed in 5.4.162 with commit a14d7038ea201c5526375becfc43b9ba281b1e82 |
| Issue introduced in 5.3 with commit c3083c80b52c4e29b65ed838d2e66a91b13a3152 and fixed in 5.10.82 with commit e52fecdd0c142b95c720683885b06ee3f0e065c8 |
| Issue introduced in 5.3 with commit c3083c80b52c4e29b65ed838d2e66a91b13a3152 and fixed in 5.15.5 with commit 118c826ef8b43efe0fda8faf419673707ee8c5e5 |
| Issue introduced in 5.3 with commit c3083c80b52c4e29b65ed838d2e66a91b13a3152 and fixed in 5.16 with commit 3f1dcaff642e75c1d2ad03f783fa8a3b1f56dd50 |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47187 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| arch/arm64/boot/dts/qcom/msm8998.dtsi |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| 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 |
