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Date:   Sun, 16 Oct 2022 17:40:33 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Peter Oberparleiter <oberpar@linux.ibm.com>
Cc:     Martin =?UTF-8?B?TGnFoWth?= <mliska@suse.cz>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] gcov: support GCC 12.1 and newer compilers
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On Fri, 14 Oct 2022 11:30:51 +0200 Peter Oberparleiter <oberpar@linux.ibm.com> wrote:

> On 13.10.2022 09:40, Martin Liška wrote:
> > Starting with GCC 12.1, there are 2 significant changes to the .gcda
> > file format that needs to be supported:
> > 
> > a) [gcov: Use system IO buffering] (23eb66d1d46a34cb28c4acbdf8a1deb80a7c5a05) changed
> >    that all sizes in the format are in bytes and not in words (4B)
> > b) [gcov: make profile merging smarter] (72e0c742bd01f8e7e6dcca64042b9ad7e75979de)
> >    add a new checksum to the file header.
> > 
> > Tested with GCC 7.5, 10.4, 12.2 and the current master.
> > 
> > Signed-off-by: Martin Liska <mliska@suse.cz>
> 
> Looks good, thanks! I successfully tested this patch on s390 using GCC
> 12.2 and 11.2.
> 
> Tested-by: Peter Oberparleiter <oberpar@linux.ibm.com>
> Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
> 
> Andrew, could you add this patch via your tree?

Sure.

The changelog doesn't tell us what the user-visible effects of this are
(please, it should do so), but it sounds to me like those effects are
"gcov is utterly busted".

So I'll add a cc:stable to this, so that people can use new gcc
versions to build older kernels.