linux-kernel - Re: math_state_restore and kernel_fpu

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Message-ID: <20140119210228.9598.qmail@science.horizon.com>
Date:	19 Jan 2014 16:02:28 -0500
From:	"George Spelvin" <linux@...izon.com>
To:	linux@...izon.com, nate@...tsmathematics.com
Cc:	adilger@...ger.ca, arjan@...ux.intel.com, jack@...e.cz,
	linux-kernel@...r.kernel.org, maarten-baert@...mail.com,
	mingo@...e.hu, suresh.b.siddha@...el.com, tglx@...utronix.de,
	viro@...iv.linux.org.uk
Subject: Re: math_state_restore and kernel_fpu_end disable interrupts?

> It's credited to Suresh Siddha, whom I've cc'ed (along with others who 
> signed off).  Suresh, if you're still around, could you comment on why 
> math_state_restore always leaves interrupts disabled, regardless of their 
> state on entry?  Is there a deep reason or is it a bug?

What the comments seemed to be implying was that it was a bug to enter
this code with interrupts enabled.  So the problem may be a little bit
more systemic; expert counsel is required.

> George, does it help your problem?

I'm trying it now.  But it takes a while for me to reproduce, and even
longer to be sure the problem has gone away.  So anything you hear from
me within a week will be bad news.
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