From: stsp <stsp2@yandex.ru>
To: Sean Christopherson <seanjc@google.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>
Cc: Peter Zijlstra <peterz@infradead.org>, Greg KH <greg@kroah.com>,
stable@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, corbet@lwn.net,
kernel-dev@igalia.com, kernel@gpiccoli.net, fenghua.yu@intel.com,
joshua@froggi.es, pgofman@codeweavers.com, pavel@denx.de,
pgriffais@valvesoftware.com, zfigura@codeweavers.com,
cristian.ciocaltea@collabora.com,
Thomas Gleixner <tglx@linutronix.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Andre Almeida <andrealmeid@igalia.com>
Subject: Re: [PATCH 6.0.y / 6.1.y] x86/split_lock: Add sysctl to control the misery mode
Date: Wed, 29 Mar 2023 22:43:38 +0500 [thread overview]
Message-ID: <0994ea3a-e197-e938-6eab-72433d6547fd@yandex.ru> (raw)
In-Reply-To: <ZCRx8YaAt7ybDlLM@google.com>
Hi Sean, thanks for a head-up!
29.03.2023 22:14, Sean Christopherson пишет:
> Resurrecting this thread with a concrete use case.
> dosemu2, which uses KVM to accelerate DOS emulation (stating the obvious), ran
> into a problem where the hardcoded (prior to this patch) behavior will effectively
> hang userspace if the 10ms sleep is interrupted, e.g. by a periodic SIGALRM[*].
Yes, and we also created a ready-to-use
host test-case with no dosemu2 involved.
> Alternatively, we could try to figure out a way to ensure forward progress without
> letting userpace run an end-around on the enforced misery, but backporting this
> patch to stable kernels seems easier.
>
> Stas, do you happen to know what the oldest stable kernel your users use, i.e.
> how far back this backport would need to go?
It seems, the "broken" code was added by
the patch b041b525dab95 which is "described"
as v5.18-rc4-1-gb041b525dab9.
So I guess the answer would be "down to 5.18".
Of course I don't believe the patch you
mention, is a real solution. Its good for
-stable, but something else needs to be
developed in the future.
prev parent reply other threads:[~2023-03-29 17:51 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-18 23:44 Guilherme G. Piccoli
2022-12-19 10:17 ` Greg KH
2022-12-19 10:59 ` Peter Zijlstra
2022-12-19 12:48 ` Guilherme G. Piccoli
2023-03-29 17:14 ` Sean Christopherson
2023-03-29 17:43 ` stsp [this message]
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