[bug report] usb: dwc2: host: Fix ISOC flow in DDMA mode

[bug report] usb: dwc2: host: Fix ISOC flow in DDMA mode

[Dan Carpenter]

Hello Minas Harutyunyan,

This is a semi-automatic email about new static checker warnings.

Commit b258e4268850 ("usb: dwc2: host: Fix ISOC flow in DDMA mode")
from Mar 13, 2024, leads to the following Smatch complaint:

    drivers/usb/dwc2/hcd_ddma.c:874 dwc2_cmpl_host_isoc_dma_desc()
    warn: variable dereferenced before check 'qtd->urb' (see line 870)

drivers/usb/dwc2/hcd_ddma.c
   869		u16 frame_desc_idx;
   870		struct urb *usb_urb = qtd->urb->priv;
                                      ^^^^^^^^^^
The patch adds a dereference

   871		u16 remain = 0;
   872		int rc = 0;
   873	
   874		if (!qtd->urb)
                    ^^^^^^^^^
The existing check is too late now

   875			return -EINVAL;
   876	

regards,
dan carpenter

Re: [bug report] usb: dwc2: host: Fix ISOC flow in DDMA mode

[Minas Harutyunyan]

Hi Greg,

On 4/5/24 14:09, Dan Carpenter wrote:
> Hello Minas Harutyunyan,
> 
> This is a semi-automatic email about new static checker warnings.
> 
> Commit b258e4268850 ("usb: dwc2: host: Fix ISOC flow in DDMA mode")
> from Mar 13, 2024, leads to the following Smatch complaint:
> 
>      drivers/usb/dwc2/hcd_ddma.c:874 dwc2_cmpl_host_isoc_dma_desc()
>      warn: variable dereferenced before check 'qtd->urb' (see line 870)
> 
> drivers/usb/dwc2/hcd_ddma.c
>     869		u16 frame_desc_idx;
>     870		struct urb *usb_urb = qtd->urb->priv;
>                                        ^^^^^^^^^^
> The patch adds a dereference
> 
>     871		u16 remain = 0;
>     872		int rc = 0;
>     873	
>     874		if (!qtd->urb)
>                      ^^^^^^^^^
> The existing check is too late now
> 
>     875			return -EINVAL;
>     876	
> 
> regards,
> dan carpenter

Should I send new version of this patch or should develop fixup patch to 
be applied to "usb-linus" branch?

Re: [bug report] usb: dwc2: host: Fix ISOC flow in DDMA mode

[Greg Kroah-Hartman]

On Mon, Apr 08, 2024 at 06:04:42AM +0000, Minas Harutyunyan wrote:
> Hi Greg,
> 
> On 4/5/24 14:09, Dan Carpenter wrote:
> > Hello Minas Harutyunyan,
> > 
> > This is a semi-automatic email about new static checker warnings.
> > 
> > Commit b258e4268850 ("usb: dwc2: host: Fix ISOC flow in DDMA mode")
> > from Mar 13, 2024, leads to the following Smatch complaint:
> > 
> >      drivers/usb/dwc2/hcd_ddma.c:874 dwc2_cmpl_host_isoc_dma_desc()
> >      warn: variable dereferenced before check 'qtd->urb' (see line 870)
> > 
> > drivers/usb/dwc2/hcd_ddma.c
> >     869		u16 frame_desc_idx;
> >     870		struct urb *usb_urb = qtd->urb->priv;
> >                                        ^^^^^^^^^^
> > The patch adds a dereference
> > 
> >     871		u16 remain = 0;
> >     872		int rc = 0;
> >     873	
> >     874		if (!qtd->urb)
> >                      ^^^^^^^^^
> > The existing check is too late now
> > 
> >     875			return -EINVAL;
> >     876	
> > 
> > regards,
> > dan carpenter
> 
> Should I send new version of this patch or should develop fixup patch to 
> be applied to "usb-linus" branch?

A fixup patch please, I can not rebase this tree.

thanks,

greg k-h