From: Pavel Skripkin <paskripkin@gmail.com>
To: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>,
LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>,
Xu Qiang <xuqiang36@huawei.com>
Subject: Re: [PATCH v3] workqueue: fix UAF in pwq_unbound_release_workfn()
Date: Thu, 15 Jul 2021 21:52:19 +0300 [thread overview]
Message-ID: <20210715215219.061a2f25@gmail.com> (raw)
In-Reply-To: <CAJhGHyA+8p7mHR4o2VoAFTxKKtAC4Aeq1cwtszaVj-OS63KUgA@mail.gmail.com>
On Thu, 15 Jul 2021 16:08:12 +0800
Lai Jiangshan <jiangshanlai@gmail.com> wrote:
> On Wed, Jul 14, 2021 at 5:16 PM Yang Yingliang
> <yangyingliang@huawei.com> wrote:
>
> >
> > Fixes: 2d5f0764b526 ("workqueue: split apply_workqueue_attrs() into
> > 3 stages") Reported-by: Hulk Robot <hulkci@huawei.com>
> > Suggested-by: Lai Jiangshan <jiangshanlai@gmail.com>
> > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> > ---
> > v3:
> > drop the v2 and v1 changes, add check pwq in
> > pwq_unbound_release_workfn() v2:
> > also use free_wqattrs_ctx() in workqueue_apply_unbound_cpumask()
> > ---
> > kernel/workqueue.c | 20 +++++++++++++-------
> > 1 file changed, 13 insertions(+), 7 deletions(-)
> >
>
> I'm fine with the code.
>
> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
>
> Hello, Pavel
>
> Could you have a test again, please?
>
Hi, Lai!
Sorry for late response.
Yes, I have started local syzkaller instance just now, so I will share
the results tomorrow.
> Thanks,
> Lai
>
> > diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> > index 50142fc08902..f148eacda55a 100644
> > --- a/kernel/workqueue.c
> > +++ b/kernel/workqueue.c
> > @@ -3676,15 +3676,21 @@ static void
> > pwq_unbound_release_workfn(struct work_struct *work)
> > unbound_release_work); struct workqueue_struct *wq = pwq->wq;
> > struct worker_pool *pool = pwq->pool;
> > - bool is_last;
> > + bool is_last = false;
> >
> > - if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
> > - return;
> > + /*
> > + * when @pwq is not linked, it doesn't hold any reference
> > to the
> > + * @wq, and @wq is invalid to access.
> > + */
> > + if (!list_empty(&pwq->pwqs_node)) {
> > + if (WARN_ON_ONCE(!(wq->flags & WQ_UNBOUND)))
> > + return;
> >
> > - mutex_lock(&wq->mutex);
> > - list_del_rcu(&pwq->pwqs_node);
> > - is_last = list_empty(&wq->pwqs);
> > - mutex_unlock(&wq->mutex);
> > + mutex_lock(&wq->mutex);
> > + list_del_rcu(&pwq->pwqs_node);
> > + is_last = list_empty(&wq->pwqs);
> > + mutex_unlock(&wq->mutex);
> > + }
> >
> > mutex_lock(&wq_pool_mutex);
> > put_unbound_pool(pool);
> > --
> > 2.25.1
> >
With regards,
Pavel Skripkin
next prev parent reply other threads:[~2021-07-15 19:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 9:19 [PATCH v3] workqueue: fix UAF in pwq_unbound_release_workfn() Yang Yingliang
2021-07-15 8:08 ` Lai Jiangshan
2021-07-15 18:52 ` Pavel Skripkin [this message]
2021-07-16 10:45 ` Pavel Skripkin
2021-07-16 16:14 ` Tejun Heo
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