Re: [PATCH v4 0/6] kasan: add workqueue and timer stack for generic KASAN

From: Walter Wu <walter-zh.wu@mediatek.com>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>,
	wsd_upstream <wsd_upstream@mediatek.com>,
	Linux-MM <linux-mm@kvack.org>, Stephen Boyd <sboyd@kernel.org>,
	Alexander Potapenko <glider@google.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	kasan-dev <kasan-dev@googlegroups.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	linux-mediatek@lists.infradead.org,
	John Stultz <john.stultz@linaro.org>,
	Andrey Konovalov <andreyknvl@google.com>,
	Tejun Heo <tj@kernel.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 0/6] kasan: add workqueue and timer stack for generic KASAN
Date: Tue, 1 Dec 2020 19:17:02 +0800	[thread overview]
Message-ID: <1606821422.6563.10.camel@mtksdccf07> (raw)
In-Reply-To: <CACT4Y+a=GmYVZwwjyXwO=_AeGy4QB9X=5x7cL76erwjPvRW6Zw@mail.gmail.com>

Hi Dmitry,

On Tue, 2020-12-01 at 08:59 +0100, 'Dmitry Vyukov' via kasan-dev wrote:
> On Wed, Sep 30, 2020 at 5:29 PM Thomas Gleixner <tglx@linutronix.de> wrote:
> >
> > On Thu, Sep 24 2020 at 12:01, Walter Wu wrote:
> > > Syzbot reports many UAF issues for workqueue or timer, see [1] and [2].
> > > In some of these access/allocation happened in process_one_work(),
> > > we see the free stack is useless in KASAN report, it doesn't help
> > > programmers to solve UAF on workqueue. The same may stand for times.
> > >
> > > This patchset improves KASAN reports by making them to have workqueue
> > > queueing stack and timer stack information. It is useful for programmers
> > > to solve use-after-free or double-free memory issue.
> > >
> > > Generic KASAN also records the last two workqueue and timer stacks and
> > > prints them in KASAN report. It is only suitable for generic KASAN.
> 
> Walter, did you mail v5?
> Checking statuses of KASAN issues and this seems to be not in linux-next.
> 

Sorry for the delay in responding to this patch. I'm busy these few
months, so that suspend processing it.
Yes, I will send it next week. But v4 need to confirm the timer stack is
useful. I haven't found an example. Do you have some suggestion about
timer?

Thanks.
Walter

> > > [1]https://groups.google.com/g/syzkaller-bugs/search?q=%22use-after-free%22+process_one_work
> > > [2]https://groups.google.com/g/syzkaller-bugs/search?q=%22use-after-free%22%20expire_timers
> >
> > How are these links useful for people who do not have a gurgle account?
> 
> This is a public mailing list archive, so effectively the same way as
> lore links ;)
> 

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