CVE-2026-93275

CVE CVE-2026-93275EUVD EUVD-2026-86147Veröffentlicht 2026-09-24T15:52:17.000Z

Was das Advisory beschreibt

In the Linux kernel, the following vulnerability has been resolved: perf/x86/intel/pt: Fix stop/start with no update If pt_event_stop() is called without PERF_EF_UPDATE flag, then perf_aux_output_end() is not called. A subsequent call to pt_event_start() will call perf_aux_output_begin() again which violates the rule against nesting and triggers a WARNING in perf_aux_output_begin(). Originally, pt_event_stop() was never called without PERF_EF_UPDATE, because the only code paths to do so are from event overflow, and Intel PT does not do that. However the introduction of group throttling by commit 9734e25fbf5ae ("perf: Fix the throttle logic for a group") meant that an Intel PT event could be throttled if it was part of a group. Throttling calls PMU ->stop() / ->start() callbacks without flags. An example is when AUX area sampling is used. The following commands hit the issue: echo 10000 > /proc/sys/kernel/perf_event_max_sample_rate perf record -F32000 --aux-sample -e '{intel_pt//u,cycles:u}' \ -- bash -c 'for i in `seq 1 100000` ; do true ; done' Use PERF_HES_UPTODATE to track whether perf_aux_output_begin() and perf_aux_output_end() are balanced. A cleared PERF_HES_UPTODATE bit indicates that an AUX output context is still open. Amend pt_event_start() / pt_event_stop() accordingly so that begin/end stay balanced: - In non-snapshot mode, stop() always closes the buffer (the buffer may have run out of space, and that accounting is done by the update), so a following start() opens a fresh one as before. - In snapshot/overwrite mode, stop() without PERF_EF_UPDATE leaves the buffer open so that pt_event_snapshot_aux() can still copy from it, and start() then only re-enables tracing instead of calling perf_aux_output_begin() again. Note that pt_event_del() calls pt_event_stop() with PERF_EF_UPDATE flag set (as is required by the documentation), so a final call to perf_aux_output_end() is assured.

Quelle: EUVD (ENISA), im Wortlaut der Meldung.

Produkte, die das Advisory nennt

Diese Angaben stammen aus der Meldung selbst, nicht aus einer Prüfung durch uns.

• Linux — Linux patch: 7.2.6; patch: 6.12.110; patch: 0; 52ca9ced3f70779589e6ecc329baffe69d8f5f7a <304844b5545f444d523286da8228a1cbc46ffffa; 52ca9ced3f70779589e6ecc329baffe69d8f5f7a <2e17bf3a469a41457a3bc31b1f8fd66b6ce94a6d; 4.1; 52ca9ced3f70779589e6ecc329baffe69d8f5f7a <cab5015ee3f25f789b4a368f2abfa65536576b78; patch: 6.18.52; 52ca9ced3f70779589e6ecc329baffe69d8f5f7a <9b919fb5512f256e9e0604faf960b2bb98aab454; patch: 7.3-rc1

Die genannten Versionen sind die Angabe der Meldung. Patchlage vergleicht keine Versionsnummern und leitet aus ihnen keine Aussage ab — welche Version installiert ist, muss ein Mensch nachsehen.

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• Linux — Linux

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