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From:   Thomas Gleixner <tglx@linutronix.de>
To:     Stephen Rothwell <sfr@canb.auug.org.au>,
        Ingo Molnar <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>
Cc:     Linux Next Mailing List <linux-next@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: linux-next: build warning after merge of the tip tree
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References: <20200330134746.627dcd93@canb.auug.org.au> <20200401085753.617c1636@canb.auug.org.au>
Date:   Wed, 01 Apr 2020 12:25:25 +0200
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Stephen Rothwell <sfr@canb.auug.org.au> writes:
> Hi all,
>
> On Mon, 30 Mar 2020 13:47:46 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>>
>> Hi all,
>> 
>> After merging the tip tree, today's linux-next build (arm
>> multi_v7_defconfig) produced this warning:
>> 
>> kernel/futex.c: In function 'do_futex':
>> kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized]
>>  1676 |   return oldval == cmparg;
>>       |          ~~~~~~~^~~~~~~~~
>> kernel/futex.c:1652:6: note: 'oldval' was declared here
>>  1652 |  int oldval, ret;
>>       |      ^~~~~~
>> 
>> Introduced by commit
>> 
>>   a08971e9488d ("futex: arch_futex_atomic_op_inuser() calling
>>   conventions change")

Huch?
 
>> but I don't see how it makes this difference :-(

Me neither. Which compiler version?

I'm using arm-linux-gnueabi-gcc (Debian 8.3.0-2) 8.3.0 which does not
show that oddity.

Thanks,

        tglx