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 <20150817080143.GA16928@gmail.com>
From: Andy Lutomirski <luto@amacapital.net>
Date: Mon, 17 Aug 2015 16:59:18 -0700
Message-ID: <CALCETrUFpqb8=dYq0q4JomaH1i51OrY48B6PKZQbaN2mOxMW+w@mail.gmail.com>
Subject: Re: [GIT PULL] x86 fixes
To: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Juergen Gross <jgross@suse.com>, Andy Lutomirski <luto@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Brian Gerst <brgerst@gmail.com>, Denys Vlasenko <dvlasenk@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
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On Mon, Aug 17, 2015 at 1:01 AM, Ingo Molnar <mingo@kernel.org> wrote:
> So when I re-introduced static allocations math-emu started working again, to a
> limited degree: on a modern distro, trying to boot /bin/bash I got a prompt, but
> various programs would segfault. I did not investigate it any deeper, I suppose
> the FPU emulation does not go far enough for modern user-space, or maybe it has
> more bugs.
>

Were you testing with just no387 or did you run a VM with SSE2 and
such turned off?

There's a *lot* of userspace that incorrectly checks for instructions
without checking for the state support.  I've filed bugs against
libgcc for this and they're still not fixed IIRC.

--Andy
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