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From:   Linus Walleij <linus.walleij@linaro.org>
Date:   Fri, 24 Dec 2021 04:13:49 +0100
Message-ID: <CACRpkda_42LSWcaq0Q8aGB+12bo2494snk1Tua62UTLjVE1fQA@mail.gmail.com>
Subject: Re: [PATCH] ARM: module: fix MODULE_PLTS not work for KASAN
To:     Ard Biesheuvel <ardb@kernel.org>
Cc:     Lecopzer Chen <lecopzer.chen@mediatek.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Russell King <linux@armlinux.org.uk>,
        Abbott Liu <liuwenliang@huawei.com>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        kasan-dev <kasan-dev@googlegroups.com>, yj.chiang@mediatek.com,
        "# 3.4.x" <stable@vger.kernel.org>, Arnd Bergmann <arnd@arndb.de>
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On Thu, Dec 23, 2021 at 12:01 PM Ard Biesheuvel <ardb@kernel.org> wrote:
> On Thu, 23 Dec 2021 at 11:16, Lecopzer Chen <lecopzer.chen@mediatek.com> wrote:
> >
> > When we run out of module space address with ko insertion,
> > and with MODULE_PLTS, module would turn to try to find memory
> > from VMALLOC address space.
> >
> > Unfortunately, with KASAN enabled, VMALLOC doesn't work without
> > VMALLOC_KASAN which is unimplemented in ARM.
(...)
> This is not the right place to fix this. If module PLTs are
> incompatible with KAsan, they should not be selectable in Kconfig at
> the same time.
>
> But ideally, we should implement KASAN_VMALLOC for ARM as well - we
> also need this for the vmap'ed stacks.

I also need it for my kernel-in-vmalloc patch, I guess it's the
reason why I can't seem to get it to work. So a lot depends on
this.

Yours,
Linus Walleij