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* [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption
@ 2025-06-17  8:43 Johan Hovold
  2025-06-17  8:43 ` [PATCH v3 1/4] " Johan Hovold
                   ` (4 more replies)
  0 siblings, 5 replies; 10+ messages in thread
From: Johan Hovold @ 2025-06-17  8:43 UTC (permalink / raw)
  To: Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, Baochen Qiang, linux-wireless,
	ath12k, linux-kernel, Johan Hovold

As a follow up to commit:

	b67d2cf14ea ("wifi: ath12k: fix ring-buffer corruption")

add the remaining missing memory barriers to make sure that destination
ring descriptors are read after the head pointers to avoid using stale
data on weakly ordered architectures like aarch64.

Also switch back to plain accesses for the descriptor fields which is
sufficient after the memory barrier.

New in v2 are two patches that add the missing barriers also for source
rings and when updating the tail pointer for destination rings.

To avoid leaking ring details from the "hal" (lmac or non-lmac), the
barriers are added to the ath12k_hal_srng_access_end() helper. For
symmetry I therefore moved also the dest ring barriers into
ath12k_hal_srng_access_begin() and made the barrier conditional.

[ Due to this change I did not add Miaoqing's reviewed-by tag. ]

Johan


Changes in v3:
 - drop reference to commit 51ad34a47e9f ("wifi: ath12k: Add drop
   descriptor handling for monitor ring") from the commit message of
   patch 1/4

Changes in v2:
 - add tested-on tags to plain access patch
 - move destination barriers into begin helper
 - fix source ring corruption (new patch)
 - fix dest ring corruption when ring is full (new patch)


Johan Hovold (4):
  wifi: ath12k: fix dest ring-buffer corruption
  wifi: ath12k: use plain access for descriptor length
  wifi: ath12k: fix source ring-buffer corruption
  wifi: ath12k: fix dest ring-buffer corruption when ring is full

 drivers/net/wireless/ath/ath12k/ce.c  |  3 --
 drivers/net/wireless/ath/ath12k/hal.c | 40 ++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 10 deletions(-)

-- 
2.49.0


^ permalink raw reply	[flat|nested] 10+ messages in thread

* [PATCH v3 1/4] wifi: ath12k: fix dest ring-buffer corruption
  2025-06-17  8:43 [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Johan Hovold
@ 2025-06-17  8:43 ` Johan Hovold
  2025-06-25  1:53   ` Baochen Qiang
  2025-06-17  8:44 ` [PATCH v3 2/4] wifi: ath12k: use plain access for descriptor length Johan Hovold
                   ` (3 subsequent siblings)
  4 siblings, 1 reply; 10+ messages in thread
From: Johan Hovold @ 2025-06-17  8:43 UTC (permalink / raw)
  To: Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, Baochen Qiang, linux-wireless,
	ath12k, linux-kernel, Johan Hovold, stable

Add the missing memory barrier to make sure that destination ring
descriptors are read after the head pointers to avoid using stale data
on weakly ordered architectures like aarch64.

The barrier is added to the ath12k_hal_srng_access_begin() helper for
symmetry with follow-on fixes for source ring buffer corruption which
will add barriers to ath12k_hal_srng_access_end().

Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Cc: stable@vger.kernel.org	# 6.3
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/net/wireless/ath/ath12k/ce.c  |  3 ---
 drivers/net/wireless/ath/ath12k/hal.c | 17 ++++++++++++++---
 2 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/ce.c b/drivers/net/wireless/ath/ath12k/ce.c
index 3f3439262cf4..f7c15b547504 100644
--- a/drivers/net/wireless/ath/ath12k/ce.c
+++ b/drivers/net/wireless/ath/ath12k/ce.c
@@ -433,9 +433,6 @@ static int ath12k_ce_completed_recv_next(struct ath12k_ce_pipe *pipe,
 		goto err;
 	}
 
-	/* Make sure descriptor is read after the head pointer. */
-	dma_rmb();
-
 	*nbytes = ath12k_hal_ce_dst_status_get_length(desc);
 
 	*skb = pipe->dest_ring->skb[sw_index];
diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
index a301898e5849..f8bd3837b9dc 100644
--- a/drivers/net/wireless/ath/ath12k/hal.c
+++ b/drivers/net/wireless/ath/ath12k/hal.c
@@ -2143,13 +2143,24 @@ void *ath12k_hal_srng_src_get_next_reaped(struct ath12k_base *ab,
 
 void ath12k_hal_srng_access_begin(struct ath12k_base *ab, struct hal_srng *srng)
 {
+	u32 hp;
+
 	lockdep_assert_held(&srng->lock);
 
-	if (srng->ring_dir == HAL_SRNG_DIR_SRC)
+	if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
 		srng->u.src_ring.cached_tp =
 			*(volatile u32 *)srng->u.src_ring.tp_addr;
-	else
-		srng->u.dst_ring.cached_hp = READ_ONCE(*srng->u.dst_ring.hp_addr);
+	} else {
+		hp = READ_ONCE(*srng->u.dst_ring.hp_addr);
+
+		if (hp != srng->u.dst_ring.cached_hp) {
+			srng->u.dst_ring.cached_hp = hp;
+			/* Make sure descriptor is read after the head
+			 * pointer.
+			 */
+			dma_rmb();
+		}
+	}
 }
 
 /* Update cached ring head/tail pointers to HW. ath12k_hal_srng_access_begin()
-- 
2.49.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH v3 2/4] wifi: ath12k: use plain access for descriptor length
  2025-06-17  8:43 [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Johan Hovold
  2025-06-17  8:43 ` [PATCH v3 1/4] " Johan Hovold
@ 2025-06-17  8:44 ` Johan Hovold
  2025-06-25  1:53   ` Baochen Qiang
  2025-06-17  8:44 ` [PATCH v3 3/4] wifi: ath12k: fix source ring-buffer corruption Johan Hovold
                   ` (2 subsequent siblings)
  4 siblings, 1 reply; 10+ messages in thread
From: Johan Hovold @ 2025-06-17  8:44 UTC (permalink / raw)
  To: Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, Baochen Qiang, linux-wireless,
	ath12k, linux-kernel, Johan Hovold

The read memory barrier added by commit 6b67d2cf14ea ("wifi: ath12k: fix
ring-buffer corruption") is enough to guarantee ordering also for plain
descriptor accesses if the length helper is ever inlined so drop the
unnecessary READ_ONCE().

Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/net/wireless/ath/ath12k/hal.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
index f8bd3837b9dc..726969cfcaec 100644
--- a/drivers/net/wireless/ath/ath12k/hal.c
+++ b/drivers/net/wireless/ath/ath12k/hal.c
@@ -1950,7 +1950,7 @@ u32 ath12k_hal_ce_dst_status_get_length(struct hal_ce_srng_dst_status_desc *desc
 {
 	u32 len;
 
-	len = le32_get_bits(READ_ONCE(desc->flags), HAL_CE_DST_STATUS_DESC_FLAGS_LEN);
+	len = le32_get_bits(desc->flags, HAL_CE_DST_STATUS_DESC_FLAGS_LEN);
 	desc->flags &= ~cpu_to_le32(HAL_CE_DST_STATUS_DESC_FLAGS_LEN);
 
 	return len;
-- 
2.49.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH v3 3/4] wifi: ath12k: fix source ring-buffer corruption
  2025-06-17  8:43 [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Johan Hovold
  2025-06-17  8:43 ` [PATCH v3 1/4] " Johan Hovold
  2025-06-17  8:44 ` [PATCH v3 2/4] wifi: ath12k: use plain access for descriptor length Johan Hovold
@ 2025-06-17  8:44 ` Johan Hovold
  2025-06-25  1:54   ` Baochen Qiang
  2025-06-17  8:44 ` [PATCH v3 4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full Johan Hovold
  2025-06-26 23:15 ` [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Jeff Johnson
  4 siblings, 1 reply; 10+ messages in thread
From: Johan Hovold @ 2025-06-17  8:44 UTC (permalink / raw)
  To: Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, Baochen Qiang, linux-wireless,
	ath12k, linux-kernel, Johan Hovold, stable

Add the missing memory barrier to make sure that LMAC source ring
descriptors are written before updating the head pointer to avoid
passing stale data to the firmware on weakly ordered architectures like
aarch64.

Note that non-LMAC rings use MMIO write accessors which have the
required write memory barrier.

Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Cc: stable@vger.kernel.org      # 6.3
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/net/wireless/ath/ath12k/hal.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
index 726969cfcaec..d8193d9577bb 100644
--- a/drivers/net/wireless/ath/ath12k/hal.c
+++ b/drivers/net/wireless/ath/ath12k/hal.c
@@ -2178,7 +2178,11 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
 			srng->u.src_ring.last_tp =
 				*(volatile u32 *)srng->u.src_ring.tp_addr;
-			*srng->u.src_ring.hp_addr = srng->u.src_ring.hp;
+			/* Make sure descriptor is written before updating the
+			 * head pointer.
+			 */
+			dma_wmb();
+			WRITE_ONCE(*srng->u.src_ring.hp_addr, srng->u.src_ring.hp);
 		} else {
 			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
 			*srng->u.dst_ring.tp_addr = srng->u.dst_ring.tp;
@@ -2187,6 +2191,10 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
 			srng->u.src_ring.last_tp =
 				*(volatile u32 *)srng->u.src_ring.tp_addr;
+			/* Assume implementation use an MMIO write accessor
+			 * which has the required wmb() so that the descriptor
+			 * is written before the updating the head pointer.
+			 */
 			ath12k_hif_write32(ab,
 					   (unsigned long)srng->u.src_ring.hp_addr -
 					   (unsigned long)ab->mem,
-- 
2.49.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* [PATCH v3 4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full
  2025-06-17  8:43 [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Johan Hovold
                   ` (2 preceding siblings ...)
  2025-06-17  8:44 ` [PATCH v3 3/4] wifi: ath12k: fix source ring-buffer corruption Johan Hovold
@ 2025-06-17  8:44 ` Johan Hovold
  2025-06-25  1:54   ` Baochen Qiang
  2025-06-26 23:15 ` [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Jeff Johnson
  4 siblings, 1 reply; 10+ messages in thread
From: Johan Hovold @ 2025-06-17  8:44 UTC (permalink / raw)
  To: Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, Baochen Qiang, linux-wireless,
	ath12k, linux-kernel, Johan Hovold, stable

Add the missing memory barriers to make sure that destination ring
descriptors are read before updating the tail pointer (and passing
ownership to the device) to avoid memory corruption on weakly ordered
architectures like aarch64 when the ring is full.

Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Cc: stable@vger.kernel.org      # 6.3
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/net/wireless/ath/ath12k/hal.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
index d8193d9577bb..6406fcf5d69f 100644
--- a/drivers/net/wireless/ath/ath12k/hal.c
+++ b/drivers/net/wireless/ath/ath12k/hal.c
@@ -2170,7 +2170,6 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 {
 	lockdep_assert_held(&srng->lock);
 
-	/* TODO: See if we need a write memory barrier here */
 	if (srng->flags & HAL_SRNG_FLAGS_LMAC_RING) {
 		/* For LMAC rings, ring pointer updates are done through FW and
 		 * hence written to a shared memory location that is read by FW
@@ -2185,7 +2184,11 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 			WRITE_ONCE(*srng->u.src_ring.hp_addr, srng->u.src_ring.hp);
 		} else {
 			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
-			*srng->u.dst_ring.tp_addr = srng->u.dst_ring.tp;
+			/* Make sure descriptor is read before updating the
+			 * tail pointer.
+			 */
+			dma_mb();
+			WRITE_ONCE(*srng->u.dst_ring.tp_addr, srng->u.dst_ring.tp);
 		}
 	} else {
 		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
@@ -2201,6 +2204,10 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
 					   srng->u.src_ring.hp);
 		} else {
 			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
+			/* Make sure descriptor is read before updating the
+			 * tail pointer.
+			 */
+			mb();
 			ath12k_hif_write32(ab,
 					   (unsigned long)srng->u.dst_ring.tp_addr -
 					   (unsigned long)ab->mem,
-- 
2.49.0


^ permalink raw reply related	[flat|nested] 10+ messages in thread

* Re: [PATCH v3 1/4] wifi: ath12k: fix dest ring-buffer corruption
  2025-06-17  8:43 ` [PATCH v3 1/4] " Johan Hovold
@ 2025-06-25  1:53   ` Baochen Qiang
  0 siblings, 0 replies; 10+ messages in thread
From: Baochen Qiang @ 2025-06-25  1:53 UTC (permalink / raw)
  To: Johan Hovold, Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, linux-wireless, ath12k, linux-kernel,
	stable



On 6/17/2025 4:43 PM, Johan Hovold wrote:
> Add the missing memory barrier to make sure that destination ring
> descriptors are read after the head pointers to avoid using stale data
> on weakly ordered architectures like aarch64.
> 
> The barrier is added to the ath12k_hal_srng_access_begin() helper for
> symmetry with follow-on fixes for source ring buffer corruption which
> will add barriers to ath12k_hal_srng_access_end().
> 
> Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Cc: stable@vger.kernel.org	# 6.3
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>  drivers/net/wireless/ath/ath12k/ce.c  |  3 ---
>  drivers/net/wireless/ath/ath12k/hal.c | 17 ++++++++++++++---
>  2 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/ce.c b/drivers/net/wireless/ath/ath12k/ce.c
> index 3f3439262cf4..f7c15b547504 100644
> --- a/drivers/net/wireless/ath/ath12k/ce.c
> +++ b/drivers/net/wireless/ath/ath12k/ce.c
> @@ -433,9 +433,6 @@ static int ath12k_ce_completed_recv_next(struct ath12k_ce_pipe *pipe,
>  		goto err;
>  	}
>  
> -	/* Make sure descriptor is read after the head pointer. */
> -	dma_rmb();
> -
>  	*nbytes = ath12k_hal_ce_dst_status_get_length(desc);
>  
>  	*skb = pipe->dest_ring->skb[sw_index];
> diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
> index a301898e5849..f8bd3837b9dc 100644
> --- a/drivers/net/wireless/ath/ath12k/hal.c
> +++ b/drivers/net/wireless/ath/ath12k/hal.c
> @@ -2143,13 +2143,24 @@ void *ath12k_hal_srng_src_get_next_reaped(struct ath12k_base *ab,
>  
>  void ath12k_hal_srng_access_begin(struct ath12k_base *ab, struct hal_srng *srng)
>  {
> +	u32 hp;
> +
>  	lockdep_assert_held(&srng->lock);
>  
> -	if (srng->ring_dir == HAL_SRNG_DIR_SRC)
> +	if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
>  		srng->u.src_ring.cached_tp =
>  			*(volatile u32 *)srng->u.src_ring.tp_addr;
> -	else
> -		srng->u.dst_ring.cached_hp = READ_ONCE(*srng->u.dst_ring.hp_addr);
> +	} else {
> +		hp = READ_ONCE(*srng->u.dst_ring.hp_addr);
> +
> +		if (hp != srng->u.dst_ring.cached_hp) {
> +			srng->u.dst_ring.cached_hp = hp;
> +			/* Make sure descriptor is read after the head
> +			 * pointer.
> +			 */
> +			dma_rmb();
> +		}
> +	}
>  }
>  
>  /* Update cached ring head/tail pointers to HW. ath12k_hal_srng_access_begin()

Reviewed-by: Baochen Qiang <quic_bqiang@quicinc.com>



^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v3 2/4] wifi: ath12k: use plain access for descriptor length
  2025-06-17  8:44 ` [PATCH v3 2/4] wifi: ath12k: use plain access for descriptor length Johan Hovold
@ 2025-06-25  1:53   ` Baochen Qiang
  0 siblings, 0 replies; 10+ messages in thread
From: Baochen Qiang @ 2025-06-25  1:53 UTC (permalink / raw)
  To: Johan Hovold, Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, linux-wireless, ath12k, linux-kernel



On 6/17/2025 4:44 PM, Johan Hovold wrote:
> The read memory barrier added by commit 6b67d2cf14ea ("wifi: ath12k: fix
> ring-buffer corruption") is enough to guarantee ordering also for plain
> descriptor accesses if the length helper is ever inlined so drop the
> unnecessary READ_ONCE().
> 
> Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>  drivers/net/wireless/ath/ath12k/hal.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
> index f8bd3837b9dc..726969cfcaec 100644
> --- a/drivers/net/wireless/ath/ath12k/hal.c
> +++ b/drivers/net/wireless/ath/ath12k/hal.c
> @@ -1950,7 +1950,7 @@ u32 ath12k_hal_ce_dst_status_get_length(struct hal_ce_srng_dst_status_desc *desc
>  {
>  	u32 len;
>  
> -	len = le32_get_bits(READ_ONCE(desc->flags), HAL_CE_DST_STATUS_DESC_FLAGS_LEN);
> +	len = le32_get_bits(desc->flags, HAL_CE_DST_STATUS_DESC_FLAGS_LEN);
>  	desc->flags &= ~cpu_to_le32(HAL_CE_DST_STATUS_DESC_FLAGS_LEN);
>  
>  	return len;


Reviewed-by: Baochen Qiang <quic_bqiang@quicinc.com>



^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v3 3/4] wifi: ath12k: fix source ring-buffer corruption
  2025-06-17  8:44 ` [PATCH v3 3/4] wifi: ath12k: fix source ring-buffer corruption Johan Hovold
@ 2025-06-25  1:54   ` Baochen Qiang
  0 siblings, 0 replies; 10+ messages in thread
From: Baochen Qiang @ 2025-06-25  1:54 UTC (permalink / raw)
  To: Johan Hovold, Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, linux-wireless, ath12k, linux-kernel,
	stable



On 6/17/2025 4:44 PM, Johan Hovold wrote:
> Add the missing memory barrier to make sure that LMAC source ring
> descriptors are written before updating the head pointer to avoid
> passing stale data to the firmware on weakly ordered architectures like
> aarch64.
> 
> Note that non-LMAC rings use MMIO write accessors which have the
> required write memory barrier.
> 
> Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Cc: stable@vger.kernel.org      # 6.3
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>  drivers/net/wireless/ath/ath12k/hal.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
> index 726969cfcaec..d8193d9577bb 100644
> --- a/drivers/net/wireless/ath/ath12k/hal.c
> +++ b/drivers/net/wireless/ath/ath12k/hal.c
> @@ -2178,7 +2178,11 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
>  		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
>  			srng->u.src_ring.last_tp =
>  				*(volatile u32 *)srng->u.src_ring.tp_addr;
> -			*srng->u.src_ring.hp_addr = srng->u.src_ring.hp;
> +			/* Make sure descriptor is written before updating the
> +			 * head pointer.
> +			 */
> +			dma_wmb();
> +			WRITE_ONCE(*srng->u.src_ring.hp_addr, srng->u.src_ring.hp);
>  		} else {
>  			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
>  			*srng->u.dst_ring.tp_addr = srng->u.dst_ring.tp;
> @@ -2187,6 +2191,10 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
>  		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
>  			srng->u.src_ring.last_tp =
>  				*(volatile u32 *)srng->u.src_ring.tp_addr;
> +			/* Assume implementation use an MMIO write accessor
> +			 * which has the required wmb() so that the descriptor
> +			 * is written before the updating the head pointer.
> +			 */
>  			ath12k_hif_write32(ab,
>  					   (unsigned long)srng->u.src_ring.hp_addr -
>  					   (unsigned long)ab->mem,

Reviewed-by: Baochen Qiang <quic_bqiang@quicinc.com>


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v3 4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full
  2025-06-17  8:44 ` [PATCH v3 4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full Johan Hovold
@ 2025-06-25  1:54   ` Baochen Qiang
  0 siblings, 0 replies; 10+ messages in thread
From: Baochen Qiang @ 2025-06-25  1:54 UTC (permalink / raw)
  To: Johan Hovold, Jeff Johnson
  Cc: Miaoqing Pan, Remi Pommarel, linux-wireless, ath12k, linux-kernel,
	stable



On 6/17/2025 4:44 PM, Johan Hovold wrote:
> Add the missing memory barriers to make sure that destination ring
> descriptors are read before updating the tail pointer (and passing
> ownership to the device) to avoid memory corruption on weakly ordered
> architectures like aarch64 when the ring is full.
> 
> Tested-on: WCN7850 hw2.0 WLAN.HMT.1.0.c5-00481-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Cc: stable@vger.kernel.org      # 6.3
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> ---
>  drivers/net/wireless/ath/ath12k/hal.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/hal.c b/drivers/net/wireless/ath/ath12k/hal.c
> index d8193d9577bb..6406fcf5d69f 100644
> --- a/drivers/net/wireless/ath/ath12k/hal.c
> +++ b/drivers/net/wireless/ath/ath12k/hal.c
> @@ -2170,7 +2170,6 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
>  {
>  	lockdep_assert_held(&srng->lock);
>  
> -	/* TODO: See if we need a write memory barrier here */
>  	if (srng->flags & HAL_SRNG_FLAGS_LMAC_RING) {
>  		/* For LMAC rings, ring pointer updates are done through FW and
>  		 * hence written to a shared memory location that is read by FW
> @@ -2185,7 +2184,11 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
>  			WRITE_ONCE(*srng->u.src_ring.hp_addr, srng->u.src_ring.hp);
>  		} else {
>  			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
> -			*srng->u.dst_ring.tp_addr = srng->u.dst_ring.tp;
> +			/* Make sure descriptor is read before updating the
> +			 * tail pointer.
> +			 */
> +			dma_mb();
> +			WRITE_ONCE(*srng->u.dst_ring.tp_addr, srng->u.dst_ring.tp);
>  		}
>  	} else {
>  		if (srng->ring_dir == HAL_SRNG_DIR_SRC) {
> @@ -2201,6 +2204,10 @@ void ath12k_hal_srng_access_end(struct ath12k_base *ab, struct hal_srng *srng)
>  					   srng->u.src_ring.hp);
>  		} else {
>  			srng->u.dst_ring.last_hp = *srng->u.dst_ring.hp_addr;
> +			/* Make sure descriptor is read before updating the
> +			 * tail pointer.
> +			 */
> +			mb();
>  			ath12k_hif_write32(ab,
>  					   (unsigned long)srng->u.dst_ring.tp_addr -
>  					   (unsigned long)ab->mem,

Reviewed-by: Baochen Qiang <quic_bqiang@quicinc.com>


^ permalink raw reply	[flat|nested] 10+ messages in thread

* Re: [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption
  2025-06-17  8:43 [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Johan Hovold
                   ` (3 preceding siblings ...)
  2025-06-17  8:44 ` [PATCH v3 4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full Johan Hovold
@ 2025-06-26 23:15 ` Jeff Johnson
  4 siblings, 0 replies; 10+ messages in thread
From: Jeff Johnson @ 2025-06-26 23:15 UTC (permalink / raw)
  To: Jeff Johnson, Johan Hovold
  Cc: Miaoqing Pan, Remi Pommarel, Baochen Qiang, linux-wireless,
	ath12k, linux-kernel


On Tue, 17 Jun 2025 10:43:58 +0200, Johan Hovold wrote:
> As a follow up to commit:
> 
> 	b67d2cf14ea ("wifi: ath12k: fix ring-buffer corruption")
> 
> add the remaining missing memory barriers to make sure that destination
> ring descriptors are read after the head pointers to avoid using stale
> data on weakly ordered architectures like aarch64.
> 
> [...]

Applied, thanks!

[1/4] wifi: ath12k: fix dest ring-buffer corruption
      commit: 8157ce533a60521f21d466eb4de45d9735b19484
[2/4] wifi: ath12k: use plain access for descriptor length
      commit: 79390f613d639f7ef913377719cc5094357e53bc
[3/4] wifi: ath12k: fix source ring-buffer corruption
      commit: e834da4cbd6fe1d24f89368bf0c80adcad212726
[4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full
      commit: ed32169be1ccb9b1a295275ba7746dc6bf103e80

Best regards,
-- 
Jeff Johnson <jeff.johnson@oss.qualcomm.com>


^ permalink raw reply	[flat|nested] 10+ messages in thread

end of thread, other threads:[~2025-06-26 23:15 UTC | newest]

Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-06-17  8:43 [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Johan Hovold
2025-06-17  8:43 ` [PATCH v3 1/4] " Johan Hovold
2025-06-25  1:53   ` Baochen Qiang
2025-06-17  8:44 ` [PATCH v3 2/4] wifi: ath12k: use plain access for descriptor length Johan Hovold
2025-06-25  1:53   ` Baochen Qiang
2025-06-17  8:44 ` [PATCH v3 3/4] wifi: ath12k: fix source ring-buffer corruption Johan Hovold
2025-06-25  1:54   ` Baochen Qiang
2025-06-17  8:44 ` [PATCH v3 4/4] wifi: ath12k: fix dest ring-buffer corruption when ring is full Johan Hovold
2025-06-25  1:54   ` Baochen Qiang
2025-06-26 23:15 ` [PATCH v3 0/4] wifi: ath12k: fix dest ring-buffer corruption Jeff Johnson

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