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Date: Mon, 13 May 2024 10:22:51 +0200
From: Pavel Machek <pavel@denx.de>
To: Sasha Levin <sashal@kernel.org>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Linus Torvalds <torvalds@linux-foundation.org>,
	syzbot+83e7f982ca045ab4405c@syzkaller.appspotmail.com,
	Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
	Andy Lutomirski <luto@kernel.org>, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	x86@kernel.org, peterz@infradead.org, xin3.li@intel.com,
	ubizjak@gmail.com, rick.p.edgecombe@intel.com, arnd@arndb.de,
	mjguzik@gmail.com, bpf@vger.kernel.org
Subject: Re: [PATCH AUTOSEL 6.1 19/25] x86/mm: Remove broken vsyscall
 emulation code from the page fault code
Message-ID: <ZkHN25mewwQsCSVl@duo.ucw.cz>
References: <20240507231231.394219-1-sashal@kernel.org>
 <20240507231231.394219-19-sashal@kernel.org>
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Hi!

> From: Linus Torvalds <torvalds@linux-foundation.org>
>=20
> [ Upstream commit 02b670c1f88e78f42a6c5aee155c7b26960ca054 ]
=2E..
> IOW, I think the only right thing is to remove that horrendously broken
> code.
>=20
> The attached patch looks like the ObviouslyCorrect(tm) thing to do.
>=20
> NOTE! This broken code goes back to this commit in 2011:
>=20
>   4fc3490114bb ("x86-64: Set siginfo and context on vsyscall emulation fa=
ults")
>=20
> .. and back then the reason was to get all the siginfo details right.
> Honestly, I do not for a moment believe that it's worth getting the sigin=
fo
> details right here, but part of the commit says:
>=20
>     This fixes issues with UML when vsyscall=3Demulate.
>=20
> .. and so my patch to remove this garbage will probably break UML in this
> situation.
>=20
> I do not believe that anybody should be running with vsyscall=3Demulate in
> 2024 in the first place, much less if you are doing things like UML. But
> let's see if somebody screams.

Surely this should not go to stable with just 14days in mainline? We
don't want stable users to scream.

Best regards,
								Pavel
--=20
DENX Software Engineering GmbH,        Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

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