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

From: Maciej Fijalkowski <[email-masked]>
Date: Wed, 7 Jun 2023 13:46:41 +0200

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

> 
> Fixes: 2ef4e45d99b1 ("octeontx2-af: Add PTP PPS Errata workaround on CN10K silicon")
> Signed-off-by: Sai Krishna <[email-masked]>
> Signed-off-by: Naveen Mamindlapalli <[email-masked]>

Reviewed-by: Maciej Fijalkowski <[email-masked]>

> ---
>  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().

> -- 
> 2.25.1