Subject: Re: [PATCH net v4 6/7] octeon_ep_vf: add protective null checks in napi callbacks for cn9k cards

From: Vadim Fedorenko <[email-masked]>
Date: Wed, 13 Nov 2024 18:02:57 +0000

On 13/11/2024 11:13, Shinas Rasheed wrote:
> During unload, at times the OQ parsed in the napi callbacks
> have been observed to be null, causing system crash.
> Add protective checks to avoid the same, for cn9k cards.
> 
> Fixes: cb7dd712189f ("octeon_ep_vf: Add driver framework and device initialization")
> Signed-off-by: Shinas Rasheed <[email-masked]>
> ---
> V4:
>    - No changes
> 
> V3: https://lore.kernel.org/all/[email-masked]/
>    - Added back "Fixes" to the changelist
> 
> V2: https://lore.kernel.org/all/[email-masked]/
>    - Split into a separate patch
>    - Added more context
> 
> V1: https://lore.kernel.org/all/[email-masked]/
> 
>   drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_cn9k.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_cn9k.c b/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_cn9k.c
> index 88937fce75f1..f1b7eda3fa42 100644
> --- a/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_cn9k.c
> +++ b/drivers/net/ethernet/marvell/octeon_ep_vf/octep_vf_cn9k.c
> @@ -273,8 +273,14 @@ static irqreturn_t octep_vf_ioq_intr_handler_cn93(void *data)
>   	struct octep_vf_oq *oq;
>   	u64 reg_val;
>   
> -	oct = vector->octep_vf_dev;
> +	if (!vector)
> +		return IRQ_HANDLED;

And again, this function is irq handler, which is
called from octep_vf_ioq_intr_handler() only if ioq_vector was properly
resolved. This check makes no sense here.

The same goes to the next patch.

> +
>   	oq = vector->oq;
> +	if (!oq)
> +		return IRQ_HANDLED;
> +
> +	oct = vector->octep_vf_dev;
>   	/* Mailbox interrupt arrives along with interrupt of tx/rx ring pair 0 */
>   	if (oq->q_no == 0) {
>   		reg_val = octep_vf_read_csr64(oct, CN93_VF_SDP_R_MBOX_PF_VF_INT(0));