In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix CPU hotplug hang when a dying CPU's tasks sit in the BPF scheduler A CPU going down has to empty its own rq. Its hotplug thread waits in sched_cpu_wait_empty() until nothing else is left, and the only thing that wakes it is balance_push(), which runs from __schedule() on the dying CPU and pushes off the migratable tasks the CPU picks. sched_ext breaks this. A task sitting on a user DSQ or held by the BPF scheduler is still counted on its rq, but an inactive CPU no longer calls ops.dispatch() and can't pull the task back. The dying CPU goes idle with the task still counted, and one of two things happens: - Another CPU consumes the task. The rq empties without a __schedule() on the dying CPU, so the hotplug thread is never woken and cpu_down() hangs holding cpu_hotplug_lock. - The task is affine only to the dying CPU. Nothing can move it, and the offline stalls until the watchdog ejects the BPF scheduler. When the rq goes offline, re-enqueue every task on it that isn't already on the local DSQ. An enqueue on an offline rq lands on the local DSQ, so the dying CPU itself picks the tasks and balance_push() pushes them off, the same as for the other sched classes. From then on no sched_ext path on another CPU can pull a task off the rq. ops.dispatch() currently stops as soon as the CPU goes inactive, and CPU hotplug then waits for an RCU grace period before taking the rq offline. A BPF-held task affine only to the dying CPU and preempted inside an RCU read-side critical section would block that grace period, and the rq would never go offline. Test SCX_RQ_ONLINE directly so that ops.dispatch() keeps running until the rq goes offline. Only the dying CPU's own hotplug thread clears the flag during teardown, and task_can_run_on_remote_rq() still keeps other rqs' tasks off the CPU.

debian_linux dla-4904: Debian dla-4904 : ata-modules-6.12.107+deb12-armmp-di - security update

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - sched_ext: Fix CPU hotplug hang when a dying CPU's tasks sit in the BPF scheduler A CPU going down has to     empty its own rq. Its hotplug thread waits in sched_cpu_wait_empty() until nothing else is left, and the     only thing that wakes it is balance_push(), which runs from __schedule() on the dying CPU and pushes off     the migratable tasks the CPU picks. sched_ext breaks this. A task sitting on a user DSQ or held by the BPF     scheduler is still counted on its rq, but an inactive CPU no longer calls ops.dispatch() and can't pull     the task back. The dying CPU goes idle with the task still counted, and one of two things happens: -     Another CPU consumes the task. The rq empties without a __schedule() on the dying CPU, so the hotplug     thread is never woken and cpu_down() hangs holding cpu_hotplug_lock. - The task is affine only to the     dying CPU. Nothing can move it, and the offline stalls until the watchdog ejects the BPF scheduler. When     the rq goes offline, re-enqueue every task on it that isn't already on the local DSQ. An enqueue on an     offline rq lands on the local DSQ, so the dying CPU itself picks the tasks and balance_push() pushes them     off, the same as for the other sched classes. From then on no sched_ext path on another CPU can pull a     task off the rq. ops.dispatch() currently stops as soon as the CPU goes inactive, and CPU hotplug then     waits for an RCU grace period before taking the rq offline. A BPF-held task affine only to the dying CPU     and preempted inside an RCU read-side critical section would block that grace period, and the rq would     never go offline. Test SCX_RQ_ONLINE directly so that ops.dispatch() keeps running until the rq goes     offline. Only the dying CPU's own hotplug thread clears the flag during teardown, and     task_can_run_on_remote_rq() still keeps other rqs' tasks off the CPU. (CVE-2026-99085)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
377900	Amazon Linux 2023 : bpftool6.12, kernel6.12, kernel6.12-devel (ALAS2023-2026-3402)	Nessus	Amazon Linux Local Security Checks	Local	high
371502	Linux Distros Unpatched Vulnerability : CVE-2026-99085	Nessus	Misc.	Local	medium

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