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CVE-2026-98087: Linux

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Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

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    In the Linux kernel, the following vulnerability has been resolved: sched/rt,dl: Skip migrate-disabled tasks when picking a push candidate A migrate_disable()'d RT task cannot be moved to another CPU, but the scheduler still keeps such a task on that CPU's pushable list (rq->rt.pushable_tasks) and still marks the runqueue RT-overloaded (rq->rt.overloaded = 1). So the RT balancer keeps treating this CPU as having a task to move away, and keeps trying to move the task, but the push can never succeed. When the head is pinned, push_rt_task() does not give up either. It falls back to pushing rq->curr instead, using the per-CPU stopper, as added by commit a7c81556ec4d ("sched: Fix migrate_disable() vs rt/dl balancing"). The CPU spends tens of milliseconds in this retry loop. The core is isolated for real-time work, but during the loop nearly half of its time is consumed by pushes that cannot succeed. An ftrace capture of the affected CPU, with sched_switch enabled and commit 94894c9c477e ("sched/rt: Skip currently executing CPU in rto_next_cpu()") applied, shows where the CPU time went. Two SCHED_FIFO tasks at equal priority shared the CPU, taskA migrate_disable()'d and queued, taskB as rq->curr. In one 89 ms window, taskB got only 52 ms of CPU. The other 37 ms went to the stopper thread. The scheduler kept trying to push taskA, the pinned head of the pushable list, fell back to pushing taskB instead, and woke the stopper 5204 times. Every one of those pushes failed and no task was moved. taskA stayed runnable and queued the whole time, and never ran. Pushing taskB fails on a re-check. find_lock_lowest_rq() drops the rq lock to take the target rq lock, then checks again with "task != pick_next_pushable_task(rq)". The task being pushed is taskB, but the pick returns taskA, the head of the pushable list. taskB is rq->curr, and set_next_task_rt() removes the running task from that list, so taskB can never be the head. The check expects a candidate taken from the pusha

    Засегнати продукти

    • Linux Linux: a7c81556ec4d341dfdbf2cc478ead89d73e474a7 преди 755476d7ba92a1f3fe2a376c515d710bc6baebc3; a7c81556ec4d341dfdbf2cc478ead89d73e474a7 преди b0c6f947057751ab4d30ccf8095cd19804fb97fa; a7c81556ec4d341dfdbf2cc478ead89d73e474a7 преди dae5c0292080dd7b9c7d784268dcf443f1f3d15e
    • Linux Linux: 5.11; преди 5.11; 6.18.53 до 6.18.*; 7.2.7 до 7.2.*; от 7.3 нататък

    История

    • 25 септември 2026 Публикувано

    Други уязвимости в Linux Linux

    Първоизточници

    CVE-2026-98087: Linux | freedomonline.bg