{"id":"CVE-2026-99105","aliases":[],"title":"sched_ext: Fix stall when a task enqueued with SCX_ENQ_LAST lands back on its CPU's local DSQ","titleSource":"Linux","descriptionSource":"Linux","products":[{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"f0e1a0643a59bf1f922fa209cec86a170b784f3f","status":"affected","lessThan":"8d891c218016b6145993e082e7f732cb69dd0e29","versionType":"git"},{"version":"f0e1a0643a59bf1f922fa209cec86a170b784f3f","status":"affected","lessThan":"396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59","versionType":"git"},{"version":"f0e1a0643a59bf1f922fa209cec86a170b784f3f","status":"affected","lessThan":"7a9df76679633cf26e0fea882a684012c6ec245a","versionType":"git"}],"defaultStatus":"unaffected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99105"},{"vendor":"Linux","name":"Linux","platforms":[],"versions":[{"version":"6.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.12","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"defaultStatus":"affected","source":"Linux","url":"https://www.cve.org/CVERecord?id=CVE-2026-99105"}],"remediation":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Fix stall when a task enqueued with SCX_ENQ_LAST lands back on its CPU's local DSQ\n\nWith SCX_OPS_ENQ_LAST, the last runnable task on a CPU is passed to\nops.enqueue() instead of being kept running. Exiting tasks without\nSCX_OPS_ENQ_EXITING, migration disabled tasks without\nSCX_OPS_ENQ_MIGRATION_DISABLED and tasks on an offline rq skip ops.enqueue()\nand go straight to the local DSQ. This happens in put_prev_task_scx() after\nthe pick has settled on idle, so nothing reschedules the CPU, which idles\nwith the task queued until an unrelated wakeup lands on it or the watchdog\nfires.\n\nscx_mitosis, which sets SCX_OPS_ENQ_LAST without SCX_OPS_ENQ_EXITING, hit\nthis during mass cgroup teardown: exiting tasks stuck in exit_mmap() for\nover 40 seconds.\n\nA task put on the local DSQ runs, as anywhere else. If the SCX_ENQ_LAST\nenqueue left the task on this CPU's local DSQ, set need_resched on the task\nbeing switched in, as proxy_resched_idle() does. resched_curr() would flag\nthe task being put instead, and __schedule() clears that right after the\npick.","severity":"unknown","score":null,"published":"2026-10-28T10:34:24.456Z","modified":"2026-10-28T10:34:24.456Z","withdrawn":false,"knownExploited":false,"affected":[],"references":["https://git.kernel.org/stable/c/8d891c218016b6145993e082e7f732cb69dd0e29","https://git.kernel.org/stable/c/396ba6f04da3fd1fb5a3d1c9535bef3f967f4e59","https://git.kernel.org/stable/c/7a9df76679633cf26e0fea882a684012c6ec245a"],"sources":[{"name":"CVE","id":"CVE-2026-99105","modified":"2026-10-28T10:34:24.456Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-99105"}],"assessments":[],"sourceAffected":[],"kev":{"status":"not-listed","checkedAt":"2026-10-28T19:55:31.817Z"},"coverage":[{"source":"NVD","status":"not-checked"},{"source":"GHSA","status":"not-checked"},{"source":"EUVD","status":"not-checked"},{"source":"EPSS","status":"not-checked"}],"evidence":[]}