Re: [PATCH net-next v2] net/ionic: avoid OOB TX partner lookup for hwstamp RXQ

On 8/12/2026 10:52 PM, Shannon Nelson wrote:
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>
>
> On 8/12/26 22:13, Anand Khoje wrote:
>> The dedicated hardware timestamp RX queue is allocated with q->index
>> equal to lif->ionic->nrxqs_per_lif. The normal txqcqs array only
>> contains the regular queue pairs, so using that index to set 
>> rxq->partner
>> can read one entry past txqcqs[] and then write through the derived
>> pointer.
>> Only link RX/TX partners for normal queue-pair indexes. Leave the 
>> hwstamp
>> RX queue unpaired, and make the XDP_TX path abort cleanly if an RX queue
>> has no TX partner.
>>
>> Fixes: 8eeed8373e1c ("ionic: Add XDP_TX support")
>> Signed-off-by: Anand Khoje <[email protected]>
>> Reviewed-by: Si-Wei Liu <[email protected]>
>> ---
>> v2:
>>   Fixed the Fixes tag.
>>
>>   drivers/net/ethernet/pensando/ionic/ionic_lif.c     | 14 
>> ++++++++++++++
>>   drivers/net/ethernet/pensando/ionic/ionic_txrx.c    |  5 ++++-
>>   2 files changed, 20 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c 
>> b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
>> index fd3ee9820531..1822361e1070 100644
>> --- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
>> +++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
>> @@ -920,9 +920,23 @@ static int ionic_lif_rxq_init(struct ionic_lif 
>> *lif, struct ionic_qcq *qcq)
>>       };
>>       int err;
>>
>> +     q->partner = NULL;
>> +
>> +     /* Only normal RX queues have matching TX queue partners,
>> +      * skip partner pairing for hwstamp RX queue.
>> +      */
>> +     if (q->index >= lif->nxqs)
>> +             goto skip_partner;
>> +
>> +     if (WARN_ON_ONCE(!lif->txqcqs ||
>> +         q->index >= lif->ionic->ntxqs_per_lif ||
>> +         !lif->txqcqs[q->index]))
>> +             return -EINVAL;
>
> This driver doesn't have any other WARN type statements, and the WARN*
> is more often frowned upon now that so many places use
> panic_on_warn.  The other place where this kind of check is done simply
> prints a dev_err() and returns -ENXIO - see ionic_txrx_enable(). Brett
> or Eric J might have another opinion, but you might stick with that
> practice here.

Thanks for pointing this out Shannon. I agree and would like to keep the 
driver consistent regarding not using WARN statements.

Brett
>
>> +
>>       q->partner = &lif->txqcqs[q->index]->q;
>>       q->partner->partner = q;
>>
>> +skip_partner:
>>       if (!lif->xdp_prog ||
>>           (lif->xdp_prog->aux && lif->xdp_prog->aux->xdp_has_frags))
>>               ctx.cmd.q_init.flags |= cpu_to_le16(IONIC_QINIT_F_SG);
>> diff --git a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c 
>> b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
>> index 301ebee2fdc5..73998d61593 100644
>> --- a/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
>> +++ b/drivers/net/ethernet/pensando/ionic/ionic_txrx.c
>> @@ -543,13 +543,18 @@ static bool ionic_run_xdp(struct ionic_rx_stats 
>> *stats,
>>               break;
>>
>>       case XDP_TX:
>> +             txq = rxq->partner;
>> +             if (unlikely(!txq)) {
>> +                     err = -EIO;
>> +                     break;
>> +             }
>> +
>>               xdpf = xdp_convert_buff_to_frame(&xdp_buf);
>>               if (!xdpf) {
>>                       err = -ENOSPC;
>>                       break;
>>               }
>>
>> -             txq = rxq->partner;
>>               nq = netdev_get_tx_queue(netdev, txq->index);
>>               __netif_tx_lock(nq, smp_processor_id());
>>               txq_trans_cond_update(nq);
>
> Other than the above, this looks fine to me.
> Reviewed-by: Shannon Nelson <[email protected]>
>