Re: [REGRESSION] sched/core merge 1c3b68f0d55b: futex_waitv lost wakeup hangs RE Engine games and PID 1 init

[Peter Zijlstra]

On Wed, Apr 22, 2026 at 03:48:16PM +0500, Mikhail Gavrilov wrote:
> On Tue, Apr 21, 2026 at 7:41 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:>
> > Specifically, see this thread:
> >
> >   https://lore.kernel.org/r/95651a71-1adf-45ba-83eb-5744bc6d4a52@xxxxxxx
> 
> You're right — it is to blame, and I was about to follow up to say so.
> 
> After sending the first mail I kept re-verifying markers with the
> stricter RE2+RE9 workload and found that 33c66eb5e984 (parent 1 of
> 1c3b68f0, which I had marked "good") actually reproduces the hang too.
> A third bisect run with the stricter workload converges unambiguously
> on:
> 
>   25500ba7e77c ("locking/mutex: Remove the list_head from struct mutex")
> 
> Parent b9bdd4b68404 ("locking/semaphore: Remove the list_head from struct
> semaphore"): good. 25500ba7e77c: bad.

Please test this:

  https://lore.kernel.org/r/20260422092335.GH3102924@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

and reply there with your findings if possible.