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Date:   Fri, 4 Dec 2020 21:19:23 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Stephen Rothwell <sfr@canb.auug.org.au>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux Next Mailing List <linux-next@vger.kernel.org>,
        Victor Chibotaru <tchibo@google.com>,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Konovalov <andreyknvl@google.com>
Subject: Re: linux-next: build warning after merge of the akpm tree
Message-Id: <20201204211923.a88aa12dc06b61780282dd1b@linux-foundation.org>
In-Reply-To: <20201204210000.660293c6@canb.auug.org.au>
References: <20201204210000.660293c6@canb.auug.org.au>
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On Fri, 4 Dec 2020 21:00:00 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:

> Hi all,
> 
> After merging the akpm tree, today's linux-next build (powerpc
> allyesconfig) produced warnings like this:
> 
> kernel/kcov.c:296:14: warning: conflicting types for built-in function '__sanitizer_cov_trace_switch'; expected 'void(long unsigned int,  void *)' [-Wbuiltin-declaration-mismatch]
>   296 | void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases)
>       |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Odd.  clang wants that signature, according to
https://clang.llvm.org/docs/SanitizerCoverage.html.  But gcc seems to
want a different signature.  Beats me - best I can do is to cc various
likely culprits ;)

Which gcc version?  Did you recently update gcc?

> ld: warning: orphan section `.data..Lubsan_data177' from `arch/powerpc/oprofile/op_model_pa6t.o' being placed in section `.data..Lubsan_data177'
> 
> (lots of these latter ones)
> 
> I don't know what produced these, but it is in the akpm-current or
> akpm trees.