Description
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Derive SCX_RQ_IN_WAKEUP from the core enqueue flags schedule_deferred_locked() skips scheduling a deferred action while SCX_RQ_IN_WAKEUP is set and relies on the task_woken_scx() call that follows a wakeup enqueue to run it. enqueue_task_scx() sets the flag from the merged enqueue flags, which include the flags stashed for a remote activation. move_remote_task_to_local_dsq() thus sets SCX_RQ_IN_WAKEUP on the destination rq when the moved task was woken up, although no task_woken_scx() follows that activation. An IMMED insert into a busy destination requests a local reenqueue during that enqueue. The request gets linked but not scheduled and stays pending until an unrelated wakeup or preemption on that CPU runs the deferred actions. The IMMED task sits behind the running task in the meantime. If nothing runs them before the scheduler is disabled, the request outlives the scheduler and points into its freed per-cpu area, which the next scheduler dereferences from run_deferred(). Test the core enqueue flags for the wakeup bit. Only the core's wakeup path is followed by task_woken_scx().
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Linux Linux
Default version status: unaffected
997967adf10ce26c3e7bd89598b3ded62b943052 to < 6c401ae426e20e53a3398a8e79afd0964c0f5110affected57ccf5ccdc56954f2a91a7f66684fd31c566bde5 to < 3fdf2ceb31e8aff77451e468bc8409e10587916aaffected57ccf5ccdc56954f2a91a7f66684fd31c566bde5 to < df5cdc2c832ca4e8a6d774596b9005558761a403affectedee502c056c4c9cce4c132ccb588e06ffe5b831c1affected6.18.19 to < 6.18.55affected6.19.9 to < 6.20affected
Linux Linux
Default version status: affected
7.0affected0 to < 7.0unaffected6.18.55 to ≤ 6.18.*unaffected7.2.9 to ≤ 7.2.*unaffected7.3 to ≤ *unaffected