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Date: Fri, 12 Feb 2016 18:00:10 +0100
From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: x86-ml <x86@kernel.org>, lkml <linux-kernel@vger.kernel.org>
Subject: Re: WARNING: CPU: 0 PID: 3031 at
 ./arch/x86/include/asm/fpu/internal.h:530 fpu__restore+0x90/0x130()
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On Thu, Feb 11, 2016 at 05:16:00PM -0800, Andy Lutomirski wrote:
>         fpu__drop(fpu);
>         if (__copy_from_user(&fpu->state.xsave, buf_fx, state_size) ||
>             __copy_from_user(&env, buf, sizeof(env))) {
>             fpstate_init(&fpu->state);
>             err = -1;
>         } else {
>             sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
>         }
> 
>         fpu->fpstate_active = 1;
> 
> <-- preempted right here

>>From IRC:

<amluto> you could try sticking a schedule() right after that fpu->fpstate_active = 1; line

>         if (use_eager_fpu()) {
>             preempt_disable();
>             fpu__restore(fpu);
>             preempt_enable();

Something for me to try when I get a chance.

-- 
Regards/Gruss,
    Boris.

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