VYPR
← All advisories
Medium severity5.5NVD Advisory· Published Sep 5, 2025· Updated Jun 17, 2026

CVE-2025-39681

CVE-2025-39681

Description

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

x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper

Since

923f3a2b48bd ("x86/resctrl: Query LLC monitoring properties once during boot")

resctrl_cpu_detect() has been moved from common CPU initialization code to the vendor-specific BSP init helper, while Hygon didn't put that call in their code.

This triggers a division by zero fault during early booting stage on our machines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries to calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale.

Add the missing resctrl_cpu_detect() in the Hygon BSP init helper.

[ bp: Massage commit message. ]

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected products

116

Patches

Vulnerability mechanics

References

10

News mentions

1