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CVE-2026-68421

sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx() PUBLISHED

Description (CNA)

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Don't warn on core-sched forced idle in put_prev_task_scx() put_prev_task_scx() warns when a runnable task drops to a lower sched_class without SCX_OPS_ENQ_LAST, on the assumption that balance_one() would have kept it running. Core scheduling breaks that: a forced-idle SMT sibling reschedules through the core_pick fast path in pick_next_task(), which skips pick_task_scx() and thus balance_one(), so a runnable task can drop to idle with ENQ_LAST unset. Gate the warning on sched_cpu_cookie_match(): a cookie mismatch means core scheduling forced the idle, while a match (or core scheduling off) still catches a genuine missing-ENQ_LAST drop.

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected 7c65ae81ea86a6ed8086e1a5651acd766187f19b before 6267ebee9f2f3e26f4968bf6dc29d350620fa320; affected 7c65ae81ea86a6ed8086e1a5651acd766187f19b before 2907e9d0f05b506dfd58aec589a23042a56ef36b; affected 7c65ae81ea86a6ed8086e1a5651acd766187f19b before e2f188cdbf8312289532c36eb4e9eb1c9544d43a; affected 7c65ae81ea86a6ed8086e1a5651acd766187f19b before b7d9c359e5cf867f7eb23df3bb1c6b9e58af24da
Linux / Linuxaffected 6.12; unaffected 0 before 6.12; unaffected 6.12.114 through 6.12.*; unaffected 6.18.42 through 6.18.*; unaffected 7.1.6 through 7.1.*; unaffected 7.2 through *

CWE

No CWE identifiers supplied.

References