Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210329125449.GA3805@willie-the-truck> <20210330081417.22011-1-lecopzer.chen@mediatek.com>
In-Reply-To: <20210330081417.22011-1-lecopzer.chen@mediatek.com>
From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Tue, 30 Mar 2021 17:41:02 +0200
Message-ID: <CA+fCnZdugY3ei_iZ3OLukdgLnGx8b0h-TmbFARXQQWwww3EZmA@mail.gmail.com>
Subject: Re: [PATCH v4 5/5] arm64: Kconfig: select KASAN_VMALLOC if
 KANSAN_GENERIC is enabled
To:     Lecopzer Chen <lecopzer.chen@mediatek.com>,
        Will Deacon <will@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Alexander Potapenko <glider@google.com>, gustavoars@kernel.org,
        kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
        LKML <linux-kernel@vger.kernel.org>, linux@roeck-us.net,
        maz@kernel.org, rppt@kernel.org,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        tyhicks@linux.microsoft.com, yj.chiang@mediatek.com,
        lecopzer@gmail.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Tue, Mar 30, 2021 at 10:14 AM Lecopzer Chen
<lecopzer.chen@mediatek.com> wrote:
>
> > Do you know if anybody is working on this? It's really unfortunate that
> > we can't move exclusively to VMAP_STACK just because of SW_TAGS KASAN.
> >
> > That said, what is there to do? As things stand, won't kernel stack
> > addresses end up using KASAN_TAG_KERNEL?
>
> Hi Andrey,
>
> Do you or any KASAN developers have already had any plan for this?

Hi Will and Lecopzer,

We have an issue open to track this [1], but no immediate plans to work on this.

Now that we have GENERIC vmalloc support for arm64, there's a chance
that SW_TAGS vmalloc will just work once allowed via configs. However,
I would expect that we'll still need to at least add some
kasan_reset_tag() annotations here and there.

Thanks!

[1] https://bugzilla.kernel.org/show_bug.cgi?id=211777