{"id":"CVE-2025-39681","title":"x86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper\n\nSince\n\n  923f3a2b48bd (\"x86/resctrl: Query LLC monitoring properties once during boot\")\n\nresctrl_cpu…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < 62f12cde10118253348a7540e85606869bd69432","Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < 873f32201df8876bdb2563e3187e79149427cab4","Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < fb81222c1559f89bfe3aa1010f6d112531d55353","Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < 7207923d8453ebfb35667c1736169f2dd796772e","Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < a9e5924daa954c9f585c1ca00358afe71d6781c4","Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < d23264c257a70dbe021b43b3bc2ee16134cd2c69","Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < d8df126349dad855cdfedd6bbf315bad2e901c2f","Linux 5.8"],"published":"2025-09-05","updated":"2026-09-08","sourceUpdated":"2026-09-08T08:42:05.979Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2025-39681","references":[{"url":"https://git.kernel.org/stable/c/62f12cde10118253348a7540e85606869bd69432"},{"url":"https://git.kernel.org/stable/c/873f32201df8876bdb2563e3187e79149427cab4"},{"url":"https://git.kernel.org/stable/c/fb81222c1559f89bfe3aa1010f6d112531d55353"},{"url":"https://git.kernel.org/stable/c/7207923d8453ebfb35667c1736169f2dd796772e"},{"url":"https://git.kernel.org/stable/c/a9e5924daa954c9f585c1ca00358afe71d6781c4"},{"url":"https://git.kernel.org/stable/c/d23264c257a70dbe021b43b3bc2ee16134cd2c69"},{"url":"https://git.kernel.org/stable/c/d8df126349dad855cdfedd6bbf315bad2e901c2f"}],"tags":["cve.org"],"epss":0.00172,"epssPercentile":0.06896,"ingestedAt":"2026-09-08T15:33:26.997Z","slug":"CVE-2025-39681","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nx86/cpu/hygon: Add missing resctrl_cpu_detect() in bsp_init helper\n\nSince\n\n  923f3a2b48bd (\"x86/resctrl: Query LLC monitoring properties once during boot\")\n\nresctrl_cpu_detect() has been moved from common CPU initialization code to\nthe vendor-specific BSP init helper, while Hygon didn't put that call in their\ncode.\n\nThis triggers a division by zero fault during early booting stage on our\nmachines with X86_FEATURE_CQM* supported, where get_rdt_mon_resources() tries\nto calculate mon_l3_config with uninitialized boot_cpu_data.x86_cache_occ_scale.\n\nAdd the missing resctrl_cpu_detect() in the Hygon BSP init helper.\n\n  [ bp: Massage commit message. ]\n\n## Affected\n\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < 62f12cde10118253348a7540e85606869bd69432`\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < 873f32201df8876bdb2563e3187e79149427cab4`\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < fb81222c1559f89bfe3aa1010f6d112531d55353`\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < 7207923d8453ebfb35667c1736169f2dd796772e`\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < a9e5924daa954c9f585c1ca00358afe71d6781c4`\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < d23264c257a70dbe021b43b3bc2ee16134cd2c69`\n- `Linux >= 923f3a2b48bdccb6a1d1f0dd48de03de7ad936d9 < d8df126349dad855cdfedd6bbf315bad2e901c2f`\n- `Linux 5.8`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}