6.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Hovold johan+linaro@kernel.org
commit ed32169be1ccb9b1a295275ba7746dc6bf103e80 upstream.
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 Reviewed-by: Baochen Qiang quic_bqiang@quicinc.com Link: https://patch.msgid.link/20250617084402.14475-5-johan+linaro@kernel.org Signed-off-by: Jeff Johnson jeff.johnson@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/wireless/ath/ath12k/hal.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
--- 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 a { 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 a 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 a 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,