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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Tue, 28 Jan 2020 07:25:59 +0100
Message-ID: <CACT4Y+a5q1dWrm+PhWH3uQRfLWZ0HOyHA6Er4V3bn9tk85TKYA@mail.gmail.com>
Subject: Re: mmotm 2020-01-23-21-12 uploaded (efi)
To:     Qian Cai <cai@lca.pw>
Cc:     Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mark Brown <broonie@kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Linux-Next Mailing List <linux-next@vger.kernel.org>,
        Michal Hocko <mhocko@suse.cz>, mm-commits@vger.kernel.org,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        Ard Biesheuvel <ardb@kernel.org>,
        linux-efi <linux-efi@vger.kernel.org>,
        kasan-dev <kasan-dev@googlegroups.com>
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On Tue, Jan 28, 2020 at 7:15 AM Qian Cai <cai@lca.pw> wrote:
> > Should be fixed by
> >
> > https://lore.kernel.org/linux-efi/20200121093912.5246-1-ardb@kernel.org/
>
> Cc kasan-devel@
>
> If everyone has to disable KASAN for the whole subdirectories like this, I am worried about we are losing testing coverage fairly quickly. Is there a bug in compiler?

My understanding is that this is invalid C code in the first place,
no? It just happened to compile with some compilers, some options and
probably only with high optimization level.
There is a known, simple fix that is used throughout the kernel -
provide empty static inline stub, or put whole calls under ifdef.