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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Thu, 29 Apr 2021 11:39:03 -0700
Message-ID: <CAKwvOdmEybM=Vij+DP0O8waL4Awi1pip2VzHhcczgNQsryqBoA@mail.gmail.com>
Subject: Re: [PATCH] smp: fix smp_call_function_single_async prototype
To:     Arnd Bergmann <arnd@kernel.org>
Cc:     Jens Axboe <axboe@kernel.dk>, Borislav Petkov <bp@suse.de>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Juergen Gross <jgross@suse.com>, Jian Cai <jiancai@google.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Guenter Roeck <linux@roeck-us.net>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Huang Ying <ying.huang@intel.com>,
        Nathan Chancellor <nathan@kernel.org>,
        clang-built-linux <clang-built-linux@googlegroups.com>
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On Thu, Apr 29, 2021 at 11:27 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> Either way, I'll give it some more time on the randconfig build machine
> before I send out v2.

SGTM and thanks for the fix.  Perhaps worth a note that this isn't
just "a violation of the calling conventions" but straight up
undefined behavior, full stop.

UBSAN folks are working on adding a catch for this as well:
https://reviews.llvm.org/D100037, see the relevant citations from the
standard.
-- 
Thanks,
~Nick Desaulniers