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References: <20230117163543.1049025-1-jannh@google.com>
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From:   Jann Horn <jannh@google.com>
Date:   Wed, 25 Jan 2023 10:49:48 +0100
Message-ID: <CAG48ez246oQD-rdnemBokm+345Uo+OejvVQk1mR4=9fXzbX0gQ@mail.gmail.com>
Subject: Re: [PATCH] fork, vmalloc: KASAN-poison backing pages of vmapped stacks
To:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org
Cc:     Uladzislau Rezki <urezki@gmail.com>,
        Christoph Hellwig <hch@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        linux-kernel@vger.kernel.org,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        kasan-dev@googlegroups.com
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On Tue, Jan 17, 2023 at 5:35 PM Jann Horn <jannh@google.com> wrote:
> KASAN (except in HW_TAGS mode) tracks memory state based on virtual
> addresses. The mappings of kernel stack pages in the linear mapping are
> currently marked as fully accessible.
> Since stack corruption issues can cause some very gnarly errors, let's be
> extra careful and tell KASAN to forbid accesses to stack memory through the
> linear mapping.
>
> Signed-off-by: Jann Horn <jannh@google.com>

@akpm please remove this one from your tree for now, it's unlikely to
work at least for now because there's code like cifs_sg_set_buf()