Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
MIME-Version: 1.0
References: <20230914015656.20856-1-xingxing.luo@unisoc.com>
 <8365ba2a-8ecd-d055-e962-3a7f2bfdbfb0@omp.ru> <CANnj+8S6AXjkdO3sQnK-H7a-TSOxbqUQi3U5H+q_8wA-JcAV5g@mail.gmail.com>
 <f3463cff-c6d5-07e7-2f94-cdcbc76d3957@omp.ru> <CANnj+8R8ueWOOE=yA-pug7EEs0DRyh65dyRV8owQae1pZv5b9g@mail.gmail.com>
In-Reply-To: <CANnj+8R8ueWOOE=yA-pug7EEs0DRyh65dyRV8owQae1pZv5b9g@mail.gmail.com>
From:   xingxing luo <xingxing0070.luo@gmail.com>
Date:   Mon, 18 Sep 2023 13:50:11 +0800
Message-ID: <CANnj+8TNryKgq8MZ+Kx9-TE6SgNEjjfP-ZzVMd_KpYn4-F9_Og@mail.gmail.com>
Subject: Re: [PATCH] usb: musb: Get the musb_qh poniter after musb_giveback
To:     Sergey Shtylyov <s.shtylyov@omp.ru>, b-liu@ti.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        xingxing luo <xingxing0070.luo@gmail.com>,
        Zhiyong.Liu@unisoc.com, Cixi.Geng1@unisoc.com,
        Orson.Zhai@unisoc.com, Chunyan Zhang <zhang.lyra@gmail.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Precedence: bulk

Add more.

On Mon, Sep 18, 2023 at 1:22=E2=80=AFPM xingxing luo <xingxing0070.luo@gmai=
l.com> wrote:
>
> On Fri, Sep 15, 2023 at 4:48=E2=80=AFPM Sergey Shtylyov <s.shtylyov@omp.r=
u> wrote:
> >
> > On 9/15/23 5:59 AM, xingxing luo wrote:
> > [...]
> >
> > >>> When multiple threads are performing USB transmission, musb->lock w=
ill be
> > >>> unlocked when musb_giveback is executed. At this time, qh may be re=
leased
> > >>> in the dequeue process in other threads, resulting in a wild pointe=
r, so
> > >>> it needs to be here get qh again, and judge whether qh is NULL, and=
 when
> > >>> dequeue, you need to set qh to NULL.
> > >>>
> > >>> Fixes: dbac5d07d13e ("usb: musb: host: don't start next rx urb if c=
urrent one failed")
> > >>> Signed-off-by: Xingxing Luo <xingxing.luo@unisoc.com>
> > >>> ---
> > >>>  drivers/usb/musb/musb_host.c | 9 ++++++++-
> > >>>  1 file changed, 8 insertions(+), 1 deletion(-)
> > >>>
> > >>> diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_h=
ost.c
> > >>> index a02c29216955..9df27db5847a 100644
> > >>> --- a/drivers/usb/musb/musb_host.c
> > >>> +++ b/drivers/usb/musb/musb_host.c
> > >>> @@ -321,10 +321,16 @@ static void musb_advance_schedule(struct musb=
 *musb, struct urb *urb,
> > >>>       musb_giveback(musb, urb, status);
> > >>>       qh->is_ready =3D ready;
> > >>>
> > >>> +     /*
> > >>> +      * musb->lock had been unlocked in musb_giveback, so somtimes=
 qh
> > >>
> > >>    Sometimes?
> >
> >    You have a typo...
> >
> > >>
> > >>> +      * may freed, need get it again
> > >>> +      */
> > >>> +     qh =3D musb_ep_get_qh(hw_ep, is_in);
> > >>> +
> > >>>       /* reclaim resources (and bandwidth) ASAP; deschedule it, and
> > >>>        * invalidate qh as soon as list_empty(&hep->urb_list)
> > >>>        */
> > >>> -     if (list_empty(&qh->hep->urb_list)) {
> > >>> +     if (qh !=3D NULL && list_empty(&qh->hep->urb_list)) {
> > >>
> > >>    Just qh, perhaps?
> > >
> > > Could you elaborate a little more?
> > > Thanks.
> >
> >    Just 'qh' gives you the same as 'qh !=3D NULL'.
>
> Ok, I will address this in the next version.
>
> >
> > [...]
> >
> > MBR, Sergey

B.R Xingxing.Luo