linux-kernel - Re: [PATCH v2] task_work: kasan: record task_work

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Date:   Tue, 16 Mar 2021 08:33:20 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Walter Wu <walter-zh.wu@...iatek.com>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Andrey Konovalov <andreyknvl@...gle.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Oleg Nesterov <oleg@...hat.com>
Cc:     kasan-dev@...glegroups.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        wsd_upstream <wsd_upstream@...iatek.com>,
        linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v2] task_work: kasan: record task_work_add() call stack

On 3/15/21 8:44 PM, Walter Wu wrote:
> Why record task_work_add() call stack?
> Syzbot reports many use-after-free issues for task_work, see [1].
> After see the free stack and the current auxiliary stack, we think
> they are useless, we don't know where register the work, this work
> may be the free call stack, so that we miss the root cause and
> don't solve the use-after-free.
> 
> Add task_work_add() call stack into KASAN auxiliary stack in
> order to improve KASAN report. It is useful for programmers
> to solve use-after-free issues.

I think this is a very useful addition, especially as task_work
proliferates.

Reviewed-by: Jens Axboe <axboe@...nel.dk>

-- 
Jens Axboe