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From: Thomas Gleixner <tglx@linutronix.de>
To: John Stultz <jstultz@google.com>, Marco Elver <elver@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Ingo Molnar <mingo@kernel.org>,
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 kasan-dev@googlegroups.com, Edward Liaw <edliaw@google.com>, Carlos Llamas
 <cmllamas@google.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v6 1/2] posix-timers: Prefer delivery of signals to the
 current thread
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 <CANDhNCqBGnAr_MSBhQxWo+-8YnPPggxoVL32zVrDB+NcoKXVPQ@mail.gmail.com>
Date: Tue, 02 Apr 2024 16:57:42 +0200
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On Mon, Apr 01 2024 at 13:17, John Stultz wrote:
> Apologies for drudging up this old thread.
> I wanted to ask if anyone had objections to including this in the -stable trees?
>
> After this and the follow-on patch e797203fb3ba
> ("selftests/timers/posix_timers: Test delivery of signals across
> threads") landed, folks testing older kernels with the latest
> selftests started to see the new test checking for this behavior to
> stall.  Thomas did submit an adjustment to the test here to avoid the
> stall: https://lore.kernel.org/lkml/20230606142031.071059989@linutronix.de/,
> but it didn't seem to land, however that would just result in the test
> failing instead of hanging.

Thanks for reminding me about this series. I completely forgot about it.

> This change does seem to cherry-pick cleanly back to at least
> stable/linux-5.10.y cleanly, so it looks simple to pull this change
> back. But I wanted to make sure there wasn't anything subtle I was
> missing before sending patches.

This test in particular exercises new functionality/behaviour, which
really has no business to be backported into stable just to make the
relevant test usable on older kernels.

Why would testing with latest tests against an older kernel be valid per
se?

Thanks,

        tglx