Subject: Re: Coverity: irdma_fill_device_info(): Null pointer dereferences

From: Jason Gunthorpe <[email-masked]>
Date: Tue, 15 Jun 2021 13:01:59 -0300

On Tue, Jun 15, 2021 at 03:58:52PM +0000, Saleem, Shiraz wrote:
> > Subject: Coverity: irdma_fill_device_info(): Null pointer dereferences
> > 
> > Hello!
> > 
> > This is an experimental semi-automated report about issues detected by Coverity
> > from a scan of next-20210608 as part of the linux-next scan project:
> > https://scan.coverity.com/projects/linux-next-weekly-scan
> > 
> > You're getting this email because you were associated with the identified lines of
> > code (noted below) that were touched by commits:
> > 
> >   Wed Jun 2 19:55:16 2021 -0300
> >     8498a30e1b94 ("RDMA/irdma: Register auxiliary driver and implement private
> > channel OPs")
> > 
> > Coverity reported the following:
> > 
> > *** CID 1505164:  Null pointer dereferences  (NULL_RETURNS)
> > /drivers/infiniband/hw/irdma/main.c: 230 in irdma_fill_device_info()
> > 224     	rf->gen_ops.register_qset = irdma_lan_register_qset;
> > 225     	rf->gen_ops.unregister_qset = irdma_lan_unregister_qset;
> > 226     	rf->hw.hw_addr = pf->hw.hw_addr;
> > 227     	rf->pcidev = pf->pdev;
> > 228     	rf->msix_count =  pf->num_rdma_msix;
> > 229     	rf->msix_entries = &pf->msix_entries[pf->rdma_base_vector];
> > vvv     CID 1505164:  Null pointer dereferences  (NULL_RETURNS)
> > vvv     Dereferencing "vsi", which is known to be "NULL".
> 
> This is a false +ve IMO.

It is because of this:

static inline struct ice_vsi *ice_get_main_vsi(struct ice_pf *pf)
{
        if (pf->vsi)
                return pf->vsi[0];

        return NULL;
}

If the above can't return null it should be rewritten

If something special about this case prevents null it should be
reworked in some way?

Jason