linux-kernel - Re: [PATCH 4/3] x86/fpu: don't use current->mm to check for a kthread

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Message-ID: <20190613190359.GF11598@zn.tnic>
Date:   Thu, 13 Jun 2019 21:03:59 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Christoph Hellwig <hch@....de>
Cc:     x86@...nel.org, Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/3] x86/fpu: don't use current->mm to check for a kthread

On Tue, Jun 04, 2019 at 07:54:12PM +0200, Christoph Hellwig wrote:
> current->mm can be non-NULL if a kthread calls use_mm.  Check for
> PF_KTHREAD instead to decide when to store user mode FP state.
> 
> Fixes: 2722146eb784 ("x86/fpu: Remove fpu->initialized")
> Reported-by: Peter Zijlstra <peterz@...radead.org>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
>  arch/x86/include/asm/fpu/internal.h | 6 +++---
>  arch/x86/kernel/fpu/core.c          | 3 ++-
>  2 files changed, 5 insertions(+), 4 deletions(-)

I had to take this one first because of the Fixes: tag and expedite it
through tip:x86/urgent. Check the tip-bot notification mail whether it
is still ok.

I'll redo the other ones ontop, or you can if you feel bored. :)

Thx.

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.