In the Linux kernel, the following vulnerability has been resolved: perf/core: Fix NULL pmu_ctx passed to pmu->sched_task() perf_pmu_sched_task()… (CVE-2026-98477)

The Linux kernel's perf/core subsystem had a vulnerability where perf_pmu_sched_task() could pass a NULL pmu_ctx pointer to the pmu->sched_task() callback, leading to a kernel NULL pointer dereference and crash (kernel oops). This occurred because perf_pmu_sched_task() returned early when cpuctx->task_ctx was set, but cpc->task_epc was only non-NULL during a scheduled task context, causing __perf_pmu_sched_task() to always pass NULL. The fix involves passing &cpc->epc, the CPU-wide context, which is safely dereferenced by armv8pmu_sched_task(), the only in-tree implementation affected. This issue was addressed in Linux kernel version 6.17 with the addition of a BRBE (bug report and bug fix).

This vulnerability can cause a kernel NULL pointer dereference leading to a kernel crash (oops) on affected systems, potentially resulting in denial of service. There is no indication of code execution or privilege escalation from the provided data. The issue affects ARMv8 PMU implementations in the Linux kernel.

A fix is available and was included in Linux kernel version 6.17. Users and administrators should update to Linux kernel 6.17 or later to remediate this issue. No additional mitigation steps are indicated by the vendor advisory.