wifi: ath12k: fix undefined behavior with __fls in dp

[ Upstream commit d48f55e773dcce8fcf9e587073452a4944011b11 ]

When max virtual ap interfaces are configured in all the bands
with ACS and hostapd restart is done every 60s,
a crash is observed at random times because of handling the
uninitialized peer fragments with fragment id of packet as 0.

"__fls" would have an undefined behavior if the argument is passed
as "0". Hence, added changes to handle the same.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Signed-off-by: Harshitha Prem <quic_hprem@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230821130343.29495-3-quic_hprem@quicinc.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/wireless/ath/ath12k/dp_rx.c b/drivers/net/wireless/ath/ath12k/dp_rx.c
index e6e64d4..17da39b 100644 (file)
--- a/drivers/net/wireless/ath/ath12k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath12k/dp_rx.c
@@ -3229,7 +3229,7 @@ static int ath12k_dp_rx_frag_h_mpdu(struct ath12k *ar,
                goto out_unlock;
        }
 
-       if (frag_no > __fls(rx_tid->rx_frag_bitmap))
+       if ((!rx_tid->rx_frag_bitmap || frag_no > __fls(rx_tid->rx_frag_bitmap)))
                __skb_queue_tail(&rx_tid->rx_frags, msdu);
        else
                ath12k_dp_rx_h_sort_frags(ab, &rx_tid->rx_frags, msdu);