Re: [PATCH v2 1/7] sched/fair: Fix zero_vruntime tracking

[John Stultz]

On Mon, Mar 30, 2026 at 2:43 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Fri, Mar 27, 2026 at 10:44:28PM -0700, John Stultz wrote:
>
> > The backtrace is usually due to stress-ng stress-ng-yield test:
>
> What actual stress-ng parameters are that, and what kind of VM are you
> running?

Just running in a loop:
  stress-ng --class scheduler --all 1 --timeout 300

I usually also run with locktorture using the following boot args:
torture.random_shuffle=1 locktorture.writer_fifo=1
locktorture.torture_type=mutex_lock locktorture.nested_locks=8
locktorture.rt_boost=1 locktorture.rt_boost_factor=50
locktorture.stutter=0

As well as cyclictest -t -p99 and my prio-inversion-demo in a loop in
the background, but I suspect they aren't necessary here.

This all on a nested VM w/ 64 vCPUs (host has 96 vCPUs).

Over the weekend I did run with CONFIG_SCHED_PROXY_EXEC disabled, and
still tripped the problem. I've added some trace_printks back in and
am working to get more details.

thanks
-john