wifi: ath11k: fix rx completion meta data corruption

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

        ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set

Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Fixes d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")

Cc [email protected] # 5.6

Link https://bugzilla.kernel.org/show_bug.cgi?id=218005

Signed-off-by Johan Hovold <[email protected]>

---

As I reported here:

https://lore.kernel.org/lkml/[email protected]/

the ath11k and ath12k appear to be missing a number of memory barriers that are required on weakly ordered architectures like aarch64 to avoid memory corruption issues.

Here's a fix for one more such case which people already seem to be hitting.

Note that I've seen one "msdu_done" bit not set warning also with this patch so whether it helps with that at all remains to be seen. I'm CCing Jens and Steev that see these warnings frequently and that may be able to help out with testing.

Johan

 drivers/net/wireless/ath/ath11k/dp_rx.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

drivers/net/wireless/ath/ath11k/dp_rx.c +16 -10

index 029ecf51c9ef..0a57b337e4c6 100644
@@ -2646,7 +2646,7 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
        struct ath11k *ar;
        struct hal_reo_dest_ring *desc;
        enum hal_reo_dest_ring_push_reason push_reason;
-       u32 cookie;
+       u32 cookie, info0, rx_msdu_info0, rx_mpdu_info0;
        int i;
 
        for (i = 0; i < MAX_RADIOS; i++)

@@ -2659,11 +2659,14 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 try_again:
        ath11k_hal_srng_access_begin(ab, srng);
 
+       /* Make sure descriptor is read after the head pointer. */
+       dma_rmb();
+
        while (likely(desc =
              (struct hal_reo_dest_ring *)ath11k_hal_srng_dst_get_next_entry(ab,
                                                                             srng))) {
                cookie = FIELD_GET(BUFFER_ADDR_INFO1_SW_COOKIE,
-                                  desc->buf_addr_info.info1);
+                                  READ_ONCE(desc->buf_addr_info.info1));
                buf_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_BUF_ID,
                                   cookie);
                mac_id = FIELD_GET(DP_RXDMA_BUF_COOKIE_PDEV_ID, cookie);

@@ -2692,8 +2695,9 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
 
                num_buffs_reaped[mac_id]++;
 
+               info0 = READ_ONCE(desc->info0);
                push_reason = FIELD_GET(HAL_REO_DEST_RING_INFO0_PUSH_REASON,
-                                       desc->info0);
+                                       info0);
                if (unlikely(push_reason !=
                             HAL_REO_DEST_RING_PUSH_REASON_ROUTING_INSTRUCTION)) {
                        dev_kfree_skb_any(msdu);

@@ -2701,18 +2705,21 @@ int ath11k_dp_process_rx(struct ath11k_base *ab, int ring_id,
                        continue;
                }
 
-               rxcb->is_first_msdu = !!(desc->rx_msdu_info.info0 &
+               rx_msdu_info0 = READ_ONCE(desc->rx_msdu_info.info0);
+               rx_mpdu_info0 = READ_ONCE(desc->rx_mpdu_info.info0);
+
+               rxcb->is_first_msdu = !!(rx_msdu_info0 &
                                         RX_MSDU_DESC_INFO0_FIRST_MSDU_IN_MPDU);
-               rxcb->is_last_msdu = !!(desc->rx_msdu_info.info0 &
+               rxcb->is_last_msdu = !!(rx_msdu_info0 &
                                        RX_MSDU_DESC_INFO0_LAST_MSDU_IN_MPDU);
-               rxcb->is_continuation = !!(desc->rx_msdu_info.info0 &
+               rxcb->is_continuation = !!(rx_msdu_info0 &
                                           RX_MSDU_DESC_INFO0_MSDU_CONTINUATION);
                rxcb->peer_id = FIELD_GET(RX_MPDU_DESC_META_DATA_PEER_ID,
-                                         desc->rx_mpdu_info.meta_data);
+                                         READ_ONCE(desc->rx_mpdu_info.meta_data));
                rxcb->seq_no = FIELD_GET(RX_MPDU_DESC_INFO0_SEQ_NUM,
-                                        desc->rx_mpdu_info.info0);
+                                        rx_mpdu_info0);
                rxcb->tid = FIELD_GET(HAL_REO_DEST_RING_INFO0_RX_QUEUE_NUM,
-                                     desc->info0);
+                                     info0);
 
                rxcb->mac_id = mac_id;
                __skb_queue_tail(&msdu_list[mac_id], msdu);
--

2.48.1

Quoted 31 lines · Johan Hovold

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

        ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set

Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Fixes d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")

Cc [email protected] # 5.6

Link https://bugzilla.kernel.org/show_bug.cgi?id=218005

Signed-off-by Johan Hovold <[email protected]>

---

As I reported here:

https://lore.kernel.org/lkml/[email protected]/

the ath11k and ath12k appear to be missing a number of memory barriers that are required on weakly ordered architectures like aarch64 to avoid memory corruption issues.

Here's a fix for one more such case which people already seem to be hitting.

Quoted 4 lines

Note that I've seen one "msdu_done" bit not set warning also with this patch so whether it helps with that at all remains to be seen. I'm CCing Jens and Steev that see these warnings frequently and that may be able to help out with testing.

While the fix is definitely a fix, it does not seem to help with the msdu_done bit in attention is not set message as I have seen it 43 times in the last 12 hours.

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

	ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set

Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Fixes d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")

Cc [email protected] # 5.6

Link https://bugzilla.kernel.org/show_bug.cgi?id=218005

Signed-off-by Johan Hovold <[email protected]>

---

As I reported here:

https://lore.kernel.org/lkml/[email protected]/

the ath11k and ath12k appear to be missing a number of memory barriers that are required on weakly ordered architectures like aarch64 to avoid memory corruption issues.

Here's a fix for one more such case which people already seem to be hitting.

Note that I've seen one "msdu_done" bit not set warning also with this patch so whether it helps with that at all remains to be seen. I'm CCing Jens and Steev that see these warnings frequently and that may be able to help out with testing.

Quoted 27 lines · Johan Hovold

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

	ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set

Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Fixes d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")

Cc [email protected] # 5.6

Link https://bugzilla.kernel.org/show_bug.cgi?id=218005

Signed-off-by Johan Hovold <[email protected]>

---

As I reported here:

https://lore.kernel.org/lkml/[email protected]/

the ath11k and ath12k appear to be missing a number of memory barriers that are required on weakly ordered architectures like aarch64 to avoid memory corruption issues.

Quoted 7 lines

Here's a fix for one more such case which people already seem to be hitting.

Note that I've seen one "msdu_done" bit not set warning also with this patch so whether it helps with that at all remains to be seen. I'm CCing Jens and Steev that see these warnings frequently and that may be able to help out with testing.

Before this patch I was seeing this "msdu_done bit" an average of about 40 times per hour... e.g. a recent boot period of 43hrs saw 1600 of these msgs. I've been testing this patch for about 10 hours now connected to the same network etc, and haven't seen this "msdu_done bit" message once. So, even if it's not completely resolving this for everyone, it seems to be a huge improvement for me.

0006:01:00.0 Network controller: Qualcomm Technologies, Inc QCNFA765 Wireless Network Adapter (rev 01)
ath11k_pci 0006:01:00.0: chip_id 0x2 chip_family 0xb board_id 0x8c soc_id 0x400c0210
ath11k_pci 0006:01:00.0: fw_version 0x11088c35 fw_build_timestamp 2024-04-17 08:34 fw_build_id WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Tested-by Clayton Craft <[email protected]>

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

	ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set

Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Fixes d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")

Cc [email protected] # 5.6

Link https://bugzilla.kernel.org/show_bug.cgi?id=218005

Signed-off-by Johan Hovold <[email protected]>

Quoted 13 lines · Johan Hovold

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

	ath11k_pci 0006:01:00.0: msdu_done bit in attention is not set

Tested-on: WCN6855 hw2.1 WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.41

Quoted 4 lines

Fixes d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")

Cc [email protected] # 5.6

Link https://bugzilla.kernel.org/show_bug.cgi?id=218005

Signed-off-by Johan Hovold <[email protected]>

Does this supersede:
[PATCH] wifi: ath11k: fix ring-buffer corruption

Add the missing memory barrier to make sure that the REO dest ring descriptor is read after the head pointer to avoid using stale data on weakly ordered architectures like aarch64.

This may fix the ring-buffer corruption worked around by commit f9fff67d2d7c ("wifi: ath11k: Fix SKB corruption in REO destination ring") by silently discarding data, and may possibly also address user reported errors like:

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