From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <owner-linux-mm@kvack.org>
Received: from mail-ot0-f199.google.com (mail-ot0-f199.google.com [74.125.82.199])
	by kanga.kvack.org (Postfix) with ESMTP id 378C96B0343
	for <linux-mm@kvack.org>; Wed, 22 Mar 2017 17:27:14 -0400 (EDT)
Received: by mail-ot0-f199.google.com with SMTP id u47so3303911ota.4
        for <linux-mm@kvack.org>; Wed, 22 Mar 2017 14:27:14 -0700 (PDT)
Received: from mail-ot0-x242.google.com (mail-ot0-x242.google.com. [2607:f8b0:4003:c0f::242])
        by mx.google.com with ESMTPS id f125si1283926oia.267.2017.03.22.14.27.12
        for <linux-mm@kvack.org>
        (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
        Wed, 22 Mar 2017 14:27:13 -0700 (PDT)
Received: by mail-ot0-x242.google.com with SMTP id i1so26967966ota.3
        for <linux-mm@kvack.org>; Wed, 22 Mar 2017 14:27:12 -0700 (PDT)
MIME-Version: 1.0
In-Reply-To: <CAK8P3a2pm2EsxOxxf7SsEObxcNFJP60JOY_78a19g2kD4pL6Rw@mail.gmail.com>
References: <20170322111022.85745-1-dvyukov@google.com> <CAK8P3a2pm2EsxOxxf7SsEObxcNFJP60JOY_78a19g2kD4pL6Rw@mail.gmail.com>
From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 22 Mar 2017 22:27:12 +0100
Message-ID: <CAK8P3a2DskgumXx5XuzN8J-T0jmhXgD5dPZ4QWBtDA3WvMCyoQ@mail.gmail.com>
Subject: Re: [PATCH] asm-generic: fix compilation failure in cmpxchg_double()
Content-Type: text/plain; charset=UTF-8
Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Mark Rutland <mark.rutland@arm.com>, Andrey Ryabinin <aryabinin@virtuozzo.com>, Peter Zijlstra <peterz@infradead.org>, Will Deacon <will.deacon@arm.com>, Linux-MM <linux-mm@kvack.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>

On Wed, Mar 22, 2017 at 12:27 PM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Wed, Mar 22, 2017 at 12:10 PM, Dmitry Vyukov <dvyukov@google.com> wrote:
>> Arnd reported that the new code leads to compilation failures
>> with some versions of gcc. I've filed gcc issue 72873,
>> but we need a kernel fix as well.
>>
>> Remove instrumentation from cmpxchg_double() for now.
>
> Thanks, I also checked that fixes the build error for me.

I got a new variant of the bug in
arch/x86/include/asm/cmpxchg_32.h:set_64bit() now.

In file included from /git/arm-soc/arch/x86/include/asm/cmpxchg.h:142:0,
                 from /git/arm-soc/arch/x86/include/asm/atomic.h:7,
                 from /git/arm-soc/arch/x86/include/asm/msr.h:66,
                 from /git/arm-soc/arch/x86/include/asm/processor.h:20,
                 from /git/arm-soc/arch/x86/include/asm/cpufeature.h:4,
                 from /git/arm-soc/arch/x86/include/asm/thread_info.h:52,
                 from /git/arm-soc/include/linux/thread_info.h:25,
                 from /git/arm-soc/arch/x86/include/asm/preempt.h:6,
                 from /git/arm-soc/include/linux/preempt.h:80,
                 from /git/arm-soc/include/linux/spinlock.h:50,
                 from /git/arm-soc/include/linux/mmzone.h:7,
                 from /git/arm-soc/include/linux/gfp.h:5,
                 from /git/arm-soc/include/linux/mm.h:9,
                 from /git/arm-soc/mm/khugepaged.c:3:
/git/arm-soc/mm/khugepaged.c: In function 'khugepaged':
/git/arm-soc/arch/x86/include/asm/cmpxchg_32.h:29:2: error: 'asm'
operand has impossible constraints
  asm volatile("\n1:\t"

Defconfig is at http://pastebin.com/raw/Pthhv5iU

       Arnd

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>