Re: [PATCH v3 1/4] usb: renesas_usbhs: gadget: fix NULL pointer dereference in ep_disable()

[Felipe Balbi <balbi@ti.com>]

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On Fri, Oct 31, 2014 at 12:06:06AM +0000, yoshihiro shimoda wrote:
> > On Thu, Oct 30, 2014 at 07:30:16PM +0900, Yoshihiro Shimoda wrote:
> > > From: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
> > >
> > > This patch fixes an issue that the NULL pointer dereference happens
> > > when we uses g_audio driver. Since the g_audio driver will call
> > > usb_ep_disable() in afunc_set_alt() before it calls usb_ep_enable(),
> > > the uep->pipe of renesas usbhs driver will be NULL. So, this patch
> > > adds a condition to avoid the oops.
> > >
> > > Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
> > > Signed-off-by: Takeshi Kihara <takeshi.kihara.df@renesas.com>
> > > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> > > Cc: <stable@vger.kernel.org>
> > > ---
> > >  drivers/usb/renesas_usbhs/mod_gadget.c |    3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/drivers/usb/renesas_usbhs/mod_gadget.c
> > > b/drivers/usb/renesas_usbhs/mod_gadget.c
> > > index 2d17c10..2d0903f 100644
> > > --- a/drivers/usb/renesas_usbhs/mod_gadget.c
> > > +++ b/drivers/usb/renesas_usbhs/mod_gadget.c
> > > @@ -602,6 +602,9 @@ static int usbhsg_ep_disable(struct usb_ep *ep)
> > >  	struct usbhsg_uep *uep = usbhsg_ep_to_uep(ep);
> > >  	struct usbhs_pipe *pipe = usbhsg_uep_to_pipe(uep);
> > >
> > > +	if (!uep || !uep->pipe)
> > 
> > how can uep ever be NULL ? Look at the definition of
> > usbhsg_ep_to_uep():
> > 
> > 	#define usbhsg_ep_to_uep(e)             container_of(e, struct usbhsg_uep, ep)
> > 
> > how can a container_of() ever return NULL ? What you should check if
> > "ep" (the argument to this function) being NULL.
> 
> Thank you for the point.
> Morimoto-san also pointed out this code at v1 patch. But I forgot to fix it...
> We can change the "if (!uep || !uep->pipe)" to "if (!pipe)".

alright, I'll wait for a new version. Thank you

-- 
balbi

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