Re: [PATCH v2] power: supply: da9150: Fix use after free bug in da9150_charger_remove due to race condition

From: Zheng Hacker <hackerzheng666@gmail.com>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Zheng Wang <zyytlz.wz@163.com>,
	njavali@marvell.com, mrangankar@marvell.com,
	GR-QLogic-Storage-Upstream@marvell.com, jejb@linux.ibm.com,
	martin.petersen@oracle.com, linux-pm@vger.kernel.org,
	linux-kernel@vger.kernel.org, 1395428693sheep@gmail.com,
	alex000young@gmail.com
Subject: Re: [PATCH v2] power: supply: da9150: Fix use after free bug in da9150_charger_remove due to race condition
Date: Mon, 13 Mar 2023 10:50:13 +0800	[thread overview]
Message-ID: <CAJedcCy7-pNmHFC1VinXWUwvzh4cQ1yi4CSSEjgdfB1iidyjQw@mail.gmail.com> (raw)
In-Reply-To: <1fdf00a0-4830-465a-801c-147472fdcd22@mercury.local>

Sebastian Reichel <sebastian.reichel@collabora.com> 于2023年3月13日周一 06:31写道：
>
> Hi,
>
> On Sun, Mar 12, 2023 at 01:46:50AM +0800, Zheng Wang wrote:
> > In da9150_charger_probe, &charger->otg_work is bound with
> > da9150_charger_otg_work. da9150_charger_otg_ncb may be
> > called to start the work.
> >
> > If we remove the module which will call da9150_charger_remove
> > to make cleanup, there may be a unfinished work. The possible
> > sequence is as follows:
> >
> > Fix it by canceling the work before cleanup in the da9150_charger_remove
> >
> > CPU0                  CPUc1
> >
> >                     |da9150_charger_otg_work
> > da9150_charger_remove      |
> > power_supply_unregister  |
> > device_unregister   |
> > power_supply_dev_release|
> > kfree(psy)          |
> >                     |
> >                     |         power_supply_changed(charger->usb);
> >                     |   //use
> >
> > Fixes: c1a281e34dae ("power: Add support for DA9150 Charger")
> > Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
> > ---
> > v2:
> > - fix wrong description in commit message and mov cancel_work_sync
> > after usb_unregister_notifier suggested by Sebastian Reichel
> > ---
>
> Thanks, queued to power-supply's fixes branch. Please make sure you
> send your patches to the correct destination next time (linux-scsi
> should be linux-pm).

Thanks for your effort. I'll keep that in mind :)

Best regards,
Zheng

>
> >  drivers/power/supply/da9150-charger.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/power/supply/da9150-charger.c b/drivers/power/supply/da9150-charger.c
> > index 14da5c595dd9..a87aeaea38e1 100644
> > --- a/drivers/power/supply/da9150-charger.c
> > +++ b/drivers/power/supply/da9150-charger.c
> > @@ -657,6 +657,7 @@ static int da9150_charger_remove(struct platform_device *pdev)
> >
> >       if (!IS_ERR_OR_NULL(charger->usb_phy))
> >               usb_unregister_notifier(charger->usb_phy, &charger->otg_nb);
> > +     cancel_work_sync(&charger->otg_work);
> >
> >       power_supply_unregister(charger->battery);
> >       power_supply_unregister(charger->usb);
> > --
> > 2.25.1
> >