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From: Patrick Schaaf <bof@bof.de>
Date: Wed, 28 Jul 2021 19:51:59 +0200
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Subject: Re: stable 5.4.135 REGRESSION / once-a-day WARNING: at kthread_is_per_cpu+0x1c/0x20
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Patrick Schaaf <bof@bof.de>, stable@vger.kernel.org, regressions@lists.linux.dev
Content-Type: text/plain; charset="UTF-8"

On Wed, Jul 28, 2021 at 7:45 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> > to roll out 5.4.135 on a few of the hosts, and encounter a rare "WARNING: CPU ... PID ... at kthread_is_per_cpu+0x1c/0x20" splat (see full dmesg below)
> >
> > Previous kernel I was running there, never seeing that, was 5.4.114
>
> Can you narrow this down to a specific commit using 'git bisect'?

Not set up for it, but can try - I normally build from .tar.xz's.
Given the WARNING seems to take a day to happen, it'll take a while to
bisect that by commits.

I'll try to revert that one 5.4.118 change in kernel/sched/fair.c, in parallel.

best regards
  Patrick