Re: [bug report] net: Prepare gro for packet consuming gro callbacks

[Dan Carpenter <dan.carpenter@oracle.com>]

On Fri, Feb 17, 2017 at 11:22:41AM +0100, Steffen Klassert wrote:
> On Fri, Feb 17, 2017 at 01:13:05PM +0300, Dan Carpenter wrote:
> > On Fri, Feb 17, 2017 at 09:18:25AM +0100, Steffen Klassert wrote:
> > > Hi Dan.
> > > 
> > > On Thu, Feb 16, 2017 at 11:11:27PM +0300, Dan Carpenter wrote:
> > > > Hello Steffen Klassert,
> > > > 
> > > > The patch 25393d3fc055: "net: Prepare gro for packet consuming gro
> > > > callbacks" from Feb 15, 2017, leads to the following Smatch
> > > > warning:
> > > > 
> > > > 	net/core/dev.c:4522 dev_gro_receive()
> > > > 	error: 'pp' dereferencing possible ERR_PTR()
> > > > 
> > > > net/core/dev.c
> > > >   4510          if (&ptype->list = head)
> > > >   4511                  goto normal;
> > > >   4512  
> > > >   4513          if (IS_ERR(pp) && PTR_ERR(pp) = -EINPROGRESS) {
> > > > 
> > > > 
> > > > Smatch sees this and assumes that it's possible for "pp" to be an error
> > > > pointer that's not -EINPROGRESS.
> > > 
> > > pp can be either a vaild pointer, NULL or -EINPROGRESS,
> > > nothing else. So I guess this is ok.
> > 
> > Could you change it to:
> > 
> > 	if (PTR_ERR(pp) = -EINPROGRESS) {
> > 
> > That would silence the warning and make the code more clear I think.
> 
> I had it like that, but some other code checking tool
> complained that I check -EINPROGRESS without checking
> if this is an error pointer. So I changed it to that
> what I have now.
> 

Why would it complain about that???

regards,
dan carpenter