[PATCH 1/2] wifi: ath11k: fix RCU stall while reaping monitor destination ring

[Jeff Johnson]

On 9/13/2024 3:07 AM, Kang Yang wrote:
> From: P Praneesh <quic_ppranees at quicinc.com>
> 
> While processing the monitor destination ring, MSDUs are reaped from the
> link descriptor based on the corresponding buf_id.
> 
> However, sometimes the driver cannot obtain a valid buffer corresponding
> to the buf_id received from the hardware. This causes an infinite loop
> in the  the link descriptor based on the corresponding buf_id. However,
> sometimes the driver cannot obtain a valid buffer corresponding to the
> buf_id received from the hardware. This causes an infinite loop in the
> destination processing, resulting in a kernel crash.

there is replicated text above, remove:
> ...     the link descriptor based on the corresponding buf_id. However,
> sometimes the driver cannot obtain a valid buffer corresponding to the
> buf_id received from the hardware. This causes an infinite loop in the

> 
> kernel log:
> ath11k_pci 0000:58:00.0: data msdu_pop: invalid buf_id 309
> ath11k_pci 0000:58:00.0: data dp_rx_monitor_link_desc_return failed
> ath11k_pci 0000:58:00.0: data msdu_pop: invalid buf_id 309
> ath11k_pci 0000:58:00.0: data dp_rx_monitor_link_desc_return failed
> ……
> 
> Fix this by skipping the problematic buf_id and reaping the next entry,
> replacing the break with the next MSDU processing.
> 
> Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30
> Tested-on: QCN9074 hw1.0 PCI WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1
> Signed-off-by: P Praneesh <quic_ppranees at quicinc.com>
> Signed-off-by: Kang Yang <quic_kangyang at quicinc.com>
> ---
>  drivers/net/wireless/ath/ath11k/dp_rx.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
> index c087d8a0f5b2..072963d3396c 100644
> --- a/drivers/net/wireless/ath/ath11k/dp_rx.c
> +++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
> @@ -4781,7 +4781,7 @@ ath11k_dp_rx_mon_mpdu_pop(struct ath11k *ar, int mac_id,
>  			if (!msdu) {
>  				ath11k_dbg(ar->ab, ATH11K_DBG_DATA,
>  					   "msdu_pop: invalid buf_id %d\n", buf_id);
> -				break;
> +				goto next_msdu;
>  			}
>  			rxcb = ATH11K_SKB_RXCB(msdu);
>  			if (!rxcb->unmapped) {
> @@ -5405,7 +5405,7 @@ ath11k_dp_rx_full_mon_mpdu_pop(struct ath11k *ar,
>  					   "full mon msdu_pop: invalid buf_id %d\n",
>  					    buf_id);
>  				spin_unlock_bh(&rx_ring->idr_lock);
> -				break;
> +				goto next_msdu;
>  			}
>  			idr_remove(&rx_ring->bufs_idr, buf_id);
>  			spin_unlock_bh(&rx_ring->idr_lock);