{"id":"CVE-2026-68421","summary":"sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Don't warn on core-sched forced idle in put_prev_task_scx()\n\nput_prev_task_scx() warns when a runnable task drops to a lower sched_class\nwithout SCX_OPS_ENQ_LAST, on the assumption that balance_one() would have\nkept it running. Core scheduling breaks that: a forced-idle SMT sibling\nreschedules through the core_pick fast path in pick_next_task(), which skips\npick_task_scx() and thus balance_one(), so a runnable task can drop to idle\nwith ENQ_LAST unset.\n\nGate the warning on sched_cpu_cookie_match(): a cookie mismatch means core\nscheduling forced the idle, while a match (or core scheduling off) still\ncatches a genuine missing-ENQ_LAST drop.","modified":"2026-08-12T04:24:32.566251489Z","published":"2026-08-10T12:04:41.946Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68421.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2907e9d0f05b506dfd58aec589a23042a56ef36b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b7d9c359e5cf867f7eb23df3bb1c6b9e58af24da"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e2f188cdbf8312289532c36eb4e9eb1c9544d43a"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/68xxx/CVE-2026-68421.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-68421"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"7c65ae81ea86a6ed8086e1a5651acd766187f19b"},{"fixed":"2907e9d0f05b506dfd58aec589a23042a56ef36b"},{"fixed":"e2f188cdbf8312289532c36eb4e9eb1c9544d43a"},{"fixed":"b7d9c359e5cf867f7eb23df3bb1c6b9e58af24da"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-68421.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.12.0"},{"fixed":"6.18.42"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.6"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-68421.json"}}],"schema_version":"1.9.0"}