linux-kernel - Re: irq_fpu_usable() is irreliable

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Message-ID: <CAHmME9qJ8zr54A+S6+6by2YDos6vc4Dfd2V6gOtraM4mgA5raQ@mail.gmail.com>
Date:	Wed, 18 Nov 2015 20:59:35 +0100
From:	"Jason A. Donenfeld" <Jason@...c4.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, mingo@...hat.com,
	hpa@...or.com, LKML <linux-kernel@...r.kernel.org>
Subject: Re: irq_fpu_usable() is irreliable

Hi Ingo,

The plot thickens, once again.

> > Also, what CPU does the test system have, Intel or AMD? The FPU behavior can be
> > very different in the two cases.
> Intel 3820QM, but inside VMWare Workstation 12.

Trying this on bare metal, the problem goes away! Though the VM is 4.2
and my bare metal is 4.3. Perhaps your recent changes did something.

But more likely, there's some funny business happening with VMWare.
Any speculation about this? Fascinating issue...

Jason
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