{"schema":"threatline.record/2","record":{"id":"CVE-2026-93275","aliases":[],"summary":"perf/x86/intel/pt: Fix stop/start with no update","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/x86/intel/pt: Fix stop/start with no update\n\nIf pt_event_stop() is called without PERF_EF_UPDATE flag, then\nperf_aux_output_end() is not called.  A subsequent call to pt_event_start()\nwill call perf_aux_output_begin() again which violates the rule against\nnesting and triggers a WARNING in perf_aux_output_begin().\n\nOriginally, pt_event_stop() was never called without PERF_EF_UPDATE,\nbecause the only code paths to do so are from event overflow, and Intel PT\ndoes not do that.\n\nHowever the introduction of group throttling by commit 9734e25fbf5ae\n(\"perf: Fix the throttle logic for a group\") meant that an Intel PT event\ncould be throttled if it was part of a group.  Throttling calls PMU\n ->stop() / ->start() callbacks without flags.\n\nAn example is when AUX area sampling is used. The following commands\nhit the issue:\n\n  echo 10000 > /proc/sys/kernel/perf_event_max_sample_rate\n\n  perf record -F32000 --aux-sample -e '{intel_pt//u,cycles:u}' \\\n  -- bash -c 'for i in `seq 1 100000` ; do true ; done'\n\nUse PERF_HES_UPTODATE to track whether perf_aux_output_begin() and\nperf_aux_output_end() are balanced.  A cleared PERF_HES_UPTODATE bit\nindicates that an AUX output context is still open.\n\nAmend pt_event_start() / pt_event_stop() accordingly so that begin/end\nstay balanced:\n\n - In non-snapshot mode, stop() always closes the buffer (the buffer may\n   have run out of space, and that accounting is done by the update), so\n   a following start() opens a fresh one as before.\n\n - In snapshot/overwrite mode, stop() without PERF_EF_UPDATE leaves the\n   buffer open so that pt_event_snapshot_aux() can still copy from it,\n   and start() then only re-enables tracing instead of calling\n   perf_aux_output_begin() again.\n\nNote that pt_event_del() calls pt_event_stop() with PERF_EF_UPDATE flag set\n(as is required by the documentation), so a final call to\nperf_aux_output_end() is assured.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93275","source_modified_at":"2026-10-19T09:08:29.668Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"9734e25fbf5ae68eb04234b2cd14a4b36ab89141","lessThan":"cab5015ee3f25f789b4a368f2abfa65536576b78","status":"affected","versionType":"git"},{"version":"9734e25fbf5ae68eb04234b2cd14a4b36ab89141","lessThan":"304844b5545f444d523286da8228a1cbc46ffffa","status":"affected","versionType":"git"},{"version":"9734e25fbf5ae68eb04234b2cd14a4b36ab89141","lessThan":"2e17bf3a469a41457a3bc31b1f8fd66b6ce94a6d","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93275","source_modified_at":"2026-10-19T09:08:29.668Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"6.16","status":"affected"},{"version":"0","lessThan":"6.16","status":"unaffected","versionType":"semver"},{"version":"6.18.52","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.6","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93275","source_modified_at":"2026-10-19T09:08:29.668Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"304844b5545f444d523286da8228a1cbc46ffffa","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-93275","source_modified_at":"2026-10-19T09:08:29.668Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"2e17bf3a469a41457a3bc31b1f8fd66b6ce94a6d","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00184,"percentile":0.07626,"score_date":"2026-10-23"},"published_at":"2026-09-24T15:52:17.064Z","modified_at":"2026-10-19T09:08:29.668Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-93275","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-19T09:08:29.668Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-93275","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/cab5015ee3f25f789b4a368f2abfa65536576b78"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/304844b5545f444d523286da8228a1cbc46ffffa"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/2e17bf3a469a41457a3bc31b1f8fd66b6ce94a6d"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-19T09:08:29.668Z","content_hash":"a822a1161800b7f27b6f7c5315f22eed5f235f1e1a9b2423a58c68cd989d0dd3"}}