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References: <20231115203401.2495875-1-iii@linux.ibm.com> <20231115203401.2495875-4-iii@linux.ibm.com>
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From:   Alexander Potapenko <glider@google.com>
Date:   Thu, 16 Nov 2023 10:41:33 +0100
Message-ID: <CAG_fn=Vw-kR4QM8jwJYQjv8ma+mh8uyGyP2SP7PhoMvn7UqYwQ@mail.gmail.com>
Subject: Re: [PATCH 03/32] kmsan: Disable KMSAN when DEFERRED_STRUCT_PAGE_INIT
 is enabled
To:     Ilya Leoshkevich <iii@linux.ibm.com>
Cc:     Alexander Gordeev <agordeev@linux.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Marco Elver <elver@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Pekka Enberg <penberg@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Christian Borntraeger <borntraeger@linux.ibm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-s390@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Sven Schnelle <svens@linux.ibm.com>
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On Wed, Nov 15, 2023 at 9:34=E2=80=AFPM Ilya Leoshkevich <iii@linux.ibm.com=
> wrote:
>
> KMSAN relies on memblock returning all available pages to it
> (see kmsan_memblock_free_pages()). It partitions these pages into 3
> categories: pages available to the buddy allocator, shadow pages and
> origin pages. This partitioning is static.
>
> If new pages appear after kmsan_init_runtime(), it is considered
> an error. DEFERRED_STRUCT_PAGE_INIT causes this, so mark it as
> incompatible with KMSAN.

In the future we could probably collect the deferred pages as well,
but it's okay to disable KMSAN for now.

> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>