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Subject: Re: linux-next: build warning after merge of the tip tree
To: Ingo Molnar <mingo@kernel.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>
References: <20161214132828.1d128963@canb.auug.org.au>
 <20161214072411.GA1635@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Artem Bityutskiy <dedekind1@gmail.com>, linux-next@vger.kernel.org,
        linux-kernel@vger.kernel.org, David Gstir <david@sigma-star.at>
From: Richard Weinberger <richard@nod.at>
Message-ID: <bd5e8291-5ace-eb83-5b63-6af8957376bf@nod.at>
Date: Wed, 14 Dec 2016 09:05:10 +0100
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Stephen, Ingo,

CC'ing David.

On 14.12.2016 08:24, Ingo Molnar wrote:
> 
> * Stephen Rothwell <sfr@canb.auug.org.au> wrote:
> 
>> Hi all,
>>
>> After merging the tip tree, today's linux-next build (x86_64 allmodconfig)
>> produced this warning:
>>
>> fs/ubifs/dir.c: In function 'ubifs_readdir':
>> fs/ubifs/dir.c:629:13: warning: 'fstr_real_len' may be used uninitialized in this function [-Wmaybe-uninitialized]
>>     fstr.len = fstr_real_len;
>>              ^
>>
>> Introduced by commit
>>
>>   f4f61d2cc6d8 ("ubifs: Implement encrypted filenames")
>>
>> This is a false positive because assignment and use are both protected by
>> "if (encrypted)".
>>
>> I have no idea why this did not turn up earlier in my builds.
> 
> FYI, f4f61d2cc6d8 is not in the -tip tree, so it cannot possibly have introduced 
> this warning.

The commit comes via my UBIFS tree. But I never saw this warning, I'm testing with both gcc-4.8 and gcc-6.1.
Let me investigate into that.

Does today's tip change some compiler flags?

Thanks,
//richard