{"id":"DEBIAN-CVE-2025-38055","details":"In the Linux kernel, the following vulnerability has been resolved:  perf/x86/intel: Fix segfault with PEBS-via-PT with sample_freq  Currently, using PEBS-via-PT with a sample frequency instead of a sample period, causes a segfault.  For example:      BUG: kernel NULL pointer dereference, address: 0000000000000195     \u003cNMI\u003e     ? __die_body.cold+0x19/0x27     ? page_fault_oops+0xca/0x290     ? exc_page_fault+0x7e/0x1b0     ? asm_exc_page_fault+0x26/0x30     ? intel_pmu_pebs_event_update_no_drain+0x40/0x60     ? intel_pmu_pebs_event_update_no_drain+0x32/0x60     intel_pmu_drain_pebs_icl+0x333/0x350     handle_pmi_common+0x272/0x3c0     intel_pmu_handle_irq+0x10a/0x2e0     perf_event_nmi_handler+0x2a/0x50  That happens because intel_pmu_pebs_event_update_no_drain() assumes all the pebs_enabled bits represent counter indexes, which is not always the case. In this particular case, bits 60 and 61 are set for PEBS-via-PT purposes.  The behaviour of PEBS-via-PT with sample frequency is questionable because although a PMI is generated (PEBS_PMI_AFTER_EACH_RECORD), the period is not adjusted anyway.  Putting that aside, fix intel_pmu_pebs_event_update_no_drain() by passing the mask of counter bits instead of 'size'.  Note, prior to the Fixes commit, 'size' would be limited to the maximum counter index, so the issue was not hit.","modified":"2026-08-27T23:05:29.136881822Z","published":"2025-06-18T10:15:38.213Z","upstream":["CVE-2025-38055"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2025-38055"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.32-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-38055.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.32-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2025-38055.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"}]}