CVE-2026-98477: perf/core: Fix NULL pmu_ctx passed to pmu->sched_task()

Published Oct 18, 2026

Updated

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

perf/core: Fix NULL pmuctx passed to pmu->schedtask()

perfpmuschedtask() returns early when cpuctx->taskctx is set, and cpc->taskepc is only non-NULL while a task context is scheduled in on this CPU. perfpmuschedtask() therefore always passes NULL:

Unable to handle kernel NULL pointer dereference at virtual address 00 pc : armv8pmuschedtask+0x14/0x50 Call trace: armv8pmuschedtask+0x14/0x50 (P) perfpmuschedtask+0xac/0x108 perfeventtaskschedout+0x6c/0xe0

Pass &cpc->epc instead, the CPU-wide context for this PMU, which the function already dereferences a few lines up to find pmu.

armv8pmuschedtask() is the only in-tree implementation that dereferences the argument, and it only reads ->pmu, so the oops needs BRBE, added in v6.17.

Affected Software

1 affected component

Linux Linux kernel

Event History

Oct 18, 2026

CVE Published

via MITRE·03:15 PM

Data Sourced

via MITRE·03:15 PM

Description

Data Sourced

via NVD·04:16 PM

Description

Frequently Asked Questions

Which systems are exposed to the kernel oops?

The oops requires BRBE support and affects the ARMv8 PMU scheduling path. The described dereference is in armv8pmu_sched_task(), the only in-tree implementation noted as dereferencing the affected argument.

What condition triggers the NULL pointer dereference?

It occurs during perf event task scheduling when __perf_pmu_sched_task() passes a NULL PMU context to the PMU sched_task callback. The NULL value results from using cpc->task_epc, which is non-NULL only while a task context is scheduled on that CPU.

What is the relevant remediation?

Apply a kernel update containing the fix that passes the CPU-wide context, &cpc->epc, to the PMU callback instead of the task context pointer. The provided stable-kernel references identify commits carrying this correction.

CVE-2026-98477: perf/core: Fix NULL pmu_ctx passed to pmu->sched_task()

Affected Software

Event History

Frequently Asked Questions

Which systems are exposed to the kernel oops?

What condition triggers the NULL pointer dereference?

What is the relevant remediation?

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Frequently Asked Questions

Which systems are exposed to the kernel oops?

What condition triggers the NULL pointer dereference?

What is the relevant remediation?