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References: <20230311174650.3979517-1-zyytlz.wz@163.com> <1fdf00a0-4830-465a-801c-147472fdcd22@mercury.local>
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From:   Zheng Hacker <hackerzheng666@gmail.com>
Date:   Mon, 13 Mar 2023 10:50:13 +0800
Message-ID: <CAJedcCy7-pNmHFC1VinXWUwvzh4cQ1yi4CSSEjgdfB1iidyjQw@mail.gmail.com>
Subject: Re: [PATCH v2] power: supply: da9150: Fix use after free bug in
 da9150_charger_remove due to race condition
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
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Sebastian Reichel <sebastian.reichel@collabora.com> =E4=BA=8E2023=E5=B9=B43=
=E6=9C=8813=E6=97=A5=E5=91=A8=E4=B8=80 06:31=E5=86=99=E9=81=93=EF=BC=9A
>
> 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_remov=
e
> >
> > 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/supp=
ly/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_de=
vice *pdev)
> >
> >       if (!IS_ERR_OR_NULL(charger->usb_phy))
> >               usb_unregister_notifier(charger->usb_phy, &charger->otg_n=
b);
> > +     cancel_work_sync(&charger->otg_work);
> >
> >       power_supply_unregister(charger->battery);
> >       power_supply_unregister(charger->usb);
> > --
> > 2.25.1
> >