CVE-2026-89521CVE-2026-89521

In the Linux kernel, the following vulnerability has been resolved: sched/core: Handle pick_task() releasing the rq lock Core scheduling's pick_next_task() breaks when a ->pick_task() implementation can release the rq lock. The selection state derived on entry is only valid while the lock is held continuously. Once a pick can drop the lock, an interleaving selection can invalidate all of it: the single-CPU fast path can commit an uncookied pick although the core went cookied during the release, and forceidle committed by the interleaving selection skews the restarted pass's accounting. Fix it by restarting the whole selection when a pick returns RETRY_TASK after releasing the lock: a single restart point above the state derivation replaces the per-loop restart labels, so a retry picks up state committed by interleaving selections and accounts and resets forceidle like a fresh selection would. need_sync and fi_before latch across retries. Clock validity can't be re-derived - there i