Re: [PATCH] sched/fair: Add null pointer check to pick_next_entity()

From: Pat Cody
Date: Fri Mar 21 2025 - 13:53:00 EST


On Thu, Mar 20, 2025 at 10:42:44PM +0000, Christian Loehle wrote:
> Did this happen on mainline? Any chance it's reproducible?

We have the following back-ported on top of 6.13:

sched/fair: Adhere to place_entity() constraints (not upstreamed, see https://lore.kernel.org/all/20250207111141.GD7145@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/)
a430d99e3490 sched/fair: Fix value reported by hot tasks pulled in /proc/schedstat
2a77e4be12cb sched/fair: Untangle NEXT_BUDDY and pick_next_task()

We don't have a repro, but the crash in pick_task_fair happens more
often than MCE crashes with our limited deployment of 6.13.