CVE-2024-49573

In the Linux kernel, the following vulnerability has been resolved:

sched/fair: Fix NEXT_BUDDY

Adam reports that enabling NEXT_BUDDY insta triggers a WARN in pick_next_entity().

Moving clear_buddies() up before the delayed dequeue bits ensures no ->next buddy becomes delayed. Further ensure no new ->next buddy ever starts as delayed.

This flaw presents no security impact on supported Red Hat products because the affected task scheduling changes are not present in Red Hat Enterprise Linux kernels. In vulnerable upstream environments, activating the NEXT_BUDDY scheduling feature can trigger internal scheduler warnings and disrupt fair queuing operations, potentially causing a denial of service. As the code path introducing this behavior was never incorporated into supported releases, Red Hat systems are not exposed to this issue.