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Subject: Re: [kbuild-all] Re: include/linux/compiler_types.h:315:38: error:
 call to '__compiletime_assert_536' declared with attribute error:
 BUILD_BUG_ON failed: offsetof(struct can_frame, len) != offsetof(struct
 canfd_frame, len) || offsetof(struct can_frame, data) != offsetof(struc...
To:     Marc Kleine-Budde <mkl@pengutronix.de>,
        Rong Chen <rong.a.chen@intel.com>,
        Patrick Menschel <menschel.p@posteo.de>
Cc:     kernel test robot <lkp@intel.com>, kbuild-all@lists.01.org,
        linux-kernel@vger.kernel.org, linux-can <linux-can@vger.kernel.org>
References: <202103210435.I0fiBGAC-lkp@intel.com>
 <dad98ebd-77a4-3305-e681-278cabe38793@hartkopp.net>
 <7f4f7e1c-194b-a903-d474-e3b742556a55@intel.com>
 <f8075a19-10e1-abf9-6d59-1a46454b74b1@hartkopp.net>
 <b10903ca-c424-b305-d981-fe0004500190@intel.com>
 <20210323073437.yo63wreqnubbeqby@pengutronix.de>
From:   Oliver Hartkopp <socketcan@hartkopp.net>
Message-ID: <7ff6bfd3-6b4b-045a-abb7-485927909587@hartkopp.net>
Date:   Tue, 23 Mar 2021 08:45:45 +0100
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On 23.03.21 08:34, Marc Kleine-Budde wrote:
> On 23.03.2021 10:54:40, Rong Chen wrote:
>> I tried arm-linux-gnueabi (gcc version 10.2.0) and the problem still
>> exists, btw we prefer to not use the latest gcc compiler to avoid
>> false positives.
> 
> FWIW:
> 
> I'm using latest debian arm compiler and the BUILD_BUG never triggered.
> gcc version 10.2.1 20210110 (Debian 10.2.1-6)
> 

Thanks Marc!

IMO we facing a compiler problem here - and we should be very happy that 
the BUILD_BUG_ON() triggered an issue after years of silence.

I do not have a good feeling about what kind of strange effects this 
compiler issue might have in other code of other projects.

So I would explicitly suggest NOT to change the af_can.c code to work 
around this compiler issue.

Let the gcc people fix their product and let them thank all of us for 
detecting it.

Regards,
Oliver