CVE-2022-50118

/// Technical description

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

powerpc/perf: Optimize clearing the pending PMI and remove WARN_ON for PMI check in power_pmu_disable

commit 2c9ac51b850d ("powerpc/perf: Fix PMU callbacks to clear

pending PMI before resetting an overflown PMC") added a new

function "pmi_irq_pending" in hw_irq.h. This function is to check

if there is a PMI marked as pending in Paca (PACA_IRQ_PMI).This is

used in power_pmu_disable in a WARN_ON. The intention here is to

provide a warning if there is PMI pending, but no counter is found

overflown.

During some of the perf runs, below warning is hit:

WARNING: CPU: 36 PID: 0 at arch/powerpc/perf/core-book3s.c:1332 power_pmu_disable+0x25c/0x2c0

Modules linked in:

-----

NIP [c000000000141c3c] power_pmu_disable+0x25c/0x2c0

LR [c000000000141c8c] power_pmu_disable+0x2ac/0x2c0

Call Trace:

[c000000baffcfb90] [c000000000141c8c] power_pmu_disable+0x2ac/0x2c0 (unreliable)

[c000000baffcfc10] [c0000000003e2f8c] perf_pmu_dis

/// 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