Re: [net PATCH] octeontx2-af: Fix pointer dereference before sanity check

[Sai Krishna Gajula]

> -----Original Message-----
> From: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> Sent: Wednesday, June 7, 2023 5:17 PM
> To: Sai Krishna Gajula <saikrishnag@xxxxxxxxxxx>
> Cc: davem@xxxxxxxxxxxxx; edumazet@xxxxxxxxxx; kuba@xxxxxxxxxx;
> pabeni@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Sunil Kovvuri Goutham <sgoutham@xxxxxxxxxxx>;
> dan.carpenter@xxxxxxxxxx; Naveen Mamindlapalli <naveenm@xxxxxxxxxxx>
> Subject: Re: [net PATCH] octeontx2-af: Fix pointer dereference before
> sanity check
> 
> On Wed, Jun 07, 2023 at 12:32:55PM +0530, Sai Krishna wrote:
> > PTP pointer is being dereferenced before NULL, error check.
> > Fixed the same to avoid NULL dereference and smatch checker warning.
> 
> please use imperative mood, you could say:
> Move validation of ptp pointer before its usage
> 
I will change in V2 patch.

> >
> > Fixes: 2ef4e45d99b1 ("octeontx2-af: Add PTP PPS Errata workaround on
> CN10K silicon")
> > Signed-off-by: Sai Krishna <saikrishnag@xxxxxxxxxxx>
> > Signed-off-by: Naveen Mamindlapalli <naveenm@xxxxxxxxxxx>
> 
> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> 
> > ---
> >  drivers/net/ethernet/marvell/octeontx2/af/ptp.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/af/ptp.c
> b/drivers/net/ethernet/marvell/octeontx2/af/ptp.c
> > index 3411e2e47d46..6a7dfb181fa8 100644
> > --- a/drivers/net/ethernet/marvell/octeontx2/af/ptp.c
> > +++ b/drivers/net/ethernet/marvell/octeontx2/af/ptp.c
> > @@ -449,12 +449,12 @@ static void ptp_remove(struct pci_dev *pdev)
> >  	struct ptp *ptp = pci_get_drvdata(pdev);
> >  	u64 clock_cfg;
> >
> > -	if (cn10k_ptp_errata(ptp) && hrtimer_active(&ptp->hrtimer))
> > -		hrtimer_cancel(&ptp->hrtimer);
> > -
> >  	if (IS_ERR_OR_NULL(ptp))
> >  		return;
> >
> > +	if (cn10k_ptp_errata(ptp) && hrtimer_active(&ptp->hrtimer))
> > +		hrtimer_cancel(&ptp->hrtimer);
> > +
> >  	/* Disable PTP clock */
> >  	clock_cfg = readq(ptp->reg_base + PTP_CLOCK_CFG);
> >  	clock_cfg &= ~PTP_CLOCK_CFG_PTP_EN;
> 
> i wonder if ptp_remove() would be able to free the struct ptp that
> ptp_probe() allocated - then you wouldn't have to use devm_kzalloc().
> 
We intend to use devm_kzalloc() so that we do not need to call kfree in the remove function. Please let us know why you prefer to manually free the resource.

Thanks,
Sai
> > --
> > 2.25.1
> >
> >