{"cve":"CVE-2022-49781","nvd":{"published":"2025-05-01T15:16:01.307","modified":"2026-06-17T05:19:07.973","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/amd: Fix crash due to race between amd_pmu_enable_all, perf NMI and throttling\n\namd_pmu_enable_all() does:\n\n      if (!test_bit(idx, cpuc->active_mask))\n              continue;\n\n      amd_pmu_enable_event(cpuc->events[idx]);\n\nA perf NMI of another event can come between these two steps. Perf NMI\nhandler internally disables and enables _all_ events, including the one\nwhich nmi-intercepted amd_pmu_enable_all() was in process of enabling.\nIf that unintentionally enabled event has very low sampling period and\ncauses immediate successive NMI, causing the event to be throttled,\ncpuc->events[idx] and cpuc->active_mask gets cleared by x86_pmu_stop().\nThis will result in amd_pmu_enable_event() getting called with event=NULL\nwhen amd_pmu_enable_all() resumes after handling the NMIs. This causes a\nkernel crash:\n\n  BUG: kernel NULL pointer dereference, address: 0000000000000198\n  #PF: supervisor read access in kernel mode\n  #PF: error_code(0x0000) - not-present page\n  [...]\n  Call Trace:\n   <TASK>\n   amd_pmu_enable_all+0x68/0xb0\n   ctx_resched+0xd9/0x150\n   event_function+0xb8/0x130\n   ? hrtimer_start_range_ns+0x141/0x4a0\n   ? perf_duration_warn+0x30/0x30\n   remote_function+0x4d/0x60\n   __flush_smp_call_function_queue+0xc4/0x500\n   flush_smp_call_function_queue+0x11d/0x1b0\n   do_idle+0x18f/0x2d0\n   cpu_startup_entry+0x19/0x20\n   start_secondary+0x121/0x160\n   secondary_startup_64_no_verify+0xe5/0xeb\n   </TASK>\n\namd_pmu_disable_all()/amd_pmu_enable_all() calls inside perf NMI handler\nwere recently added as part of BRS enablement but I'm not sure whether\nwe really need them. We can just disable BRS in the beginning and enable\nit back while returning from NMI. This will solve the issue by not\nenabling those events whose active_masks are set but are not yet enabled\nin hw pmu.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H","score":4.7},"cwes":["CWE-362"],"references":["https://git.kernel.org/stable/c/baa014b9543c8e5e94f5d15b66abfe60750b8284","https://git.kernel.org/stable/c/fd5e454b856ed86b090336e269695d9908609b71"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:01:22.920403922+00:00"},"epss":{"cve":"CVE-2022-49781","score":0.0012,"percentile":0.01796,"date":"2026-11-01"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}