linux-kernel - Re: [PATCH] workqueue: Fix UAF report by KASAN in pwq_release

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Date:   Mon, 18 Sep 2023 17:18:37 +0800
From:   Z qiang <qiang.zhang1211@...il.com>
To:     Tejun Heo <tj@...nel.org>
Cc:     jiangshanlai@...il.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] workqueue: Fix UAF report by KASAN in pwq_release_workfn()

>
> >
> > On Wed, Sep 06, 2023 at 10:12:34AM +0800, Z qiang wrote:
> > > Flush the pwq_release_worker is insufficient, the call_rcu() is
> > > invoked to release wq
> > > in pwq_release_workfn(), this is also asynchronous.
> >
> > But rcu_free_pwq() doesn't access wq or anything. The last access is from
> > the work function.
>
> The rcu_free_wq() will access wq->cpu_pwq or unbound_attrs,
> but  at this time, the kfree(wq) may have been called in alloc_workqueue().
>

Friendly ping.

Thanks
Zqiang

> Thanks
> Zqiang
>
>
> >
> > Thanks.
> >
> > --
> > tejun