Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2;
MIME-Version: 1.0
References: <20231121220155.1217090-1-iii@linux.ibm.com> <20231121220155.1217090-33-iii@linux.ibm.com>
 <CAG_fn=V5zMxGUQ=KmJh-ghTUHa-AZYn1CPTQNbf3x7Lu0w=HvA@mail.gmail.com> <13e3e073f6ed6aa48b39ec16add85baa677d17b4.camel@linux.ibm.com>
In-Reply-To: <13e3e073f6ed6aa48b39ec16add85baa677d17b4.camel@linux.ibm.com>
From:   Alexander Potapenko <glider@google.com>
Date:   Mon, 11 Dec 2023 11:45:22 +0100
Message-ID: <CAG_fn=UX=8HrFzCSxmPgMn=H4cVmZ4GHE0Z+qZbpysOZwuH=aw@mail.gmail.com>
Subject: Re: [PATCH v2 32/33] s390: Implement the architecture-specific kmsan functions
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>,
        Heiko Carstens <hca@linux.ibm.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>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

> > Is there a possibility for infinite recursion here? E.g. can
> > `lowcore_ptr[raw_smp_processor_id()]` point somewhere in between
> > `(void *)&S390_lowcore` and `(void *)(&S390_lowcore + 1))`?
>
> No, it's allocated with __get_free_pages() or memblock_alloc_low().
> But since this question came up, I should probably add a check and
> a WARN_ON_ONCE() here.

Yes, please.


--=20
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Stra=C3=9Fe, 33
80636 M=C3=BCnchen

Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Liana Sebastian
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg