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From:   Marco Elver <elver@google.com>
Date:   Tue, 12 Jul 2022 15:43:31 +0200
Message-ID: <CANpmjNMpCow-pwqQnw8aHRUZKuBcOUU4On=JgEgysT8SBTrz6g@mail.gmail.com>
Subject: Re: [PATCH v4 33/45] x86: kmsan: disable instrumentation of
 unsupported code
To:     Alexander Potapenko <glider@google.com>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Alexei Starovoitov <ast@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andrey Konovalov <andreyknvl@google.com>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Christoph Hellwig <hch@lst.de>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Eric Dumazet <edumazet@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Ilya Leoshkevich <iii@linux.ibm.com>,
        Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Kees Cook <keescook@chromium.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Matthew Wilcox <willy@infradead.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Pekka Enberg <penberg@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vegard Nossum <vegard.nossum@oracle.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        linux-mm@kvack.org, linux-arch@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Fri, 1 Jul 2022 at 16:24, 'Alexander Potapenko' via kasan-dev
<kasan-dev@googlegroups.com> wrote:
[...]
> ---
>  arch/x86/boot/Makefile            | 1 +
>  arch/x86/boot/compressed/Makefile | 1 +
>  arch/x86/entry/vdso/Makefile      | 3 +++
>  arch/x86/kernel/Makefile          | 2 ++
>  arch/x86/kernel/cpu/Makefile      | 1 +
>  arch/x86/mm/Makefile              | 2 ++
>  arch/x86/realmode/rm/Makefile     | 1 +
>  lib/Makefile                      | 2 ++
[...]
> --- a/lib/Makefile
> +++ b/lib/Makefile
> @@ -272,6 +272,8 @@ obj-$(CONFIG_POLYNOMIAL) += polynomial.o
>  CFLAGS_stackdepot.o += -fno-builtin
>  obj-$(CONFIG_STACKDEPOT) += stackdepot.o
>  KASAN_SANITIZE_stackdepot.o := n
> +# In particular, instrumenting stackdepot.c with KMSAN will result in infinite
> +# recursion.
>  KMSAN_SANITIZE_stackdepot.o := n
>  KCOV_INSTRUMENT_stackdepot.o := n

This is generic code and not x86, should it have been in the earlier patch?