wifi: ath12k: avoid double DMA unmap of held monitor RX buffers

Browse source

ath12k_dp_cc_cleanup() assumes that every rx_desc_info entry with a
non-NULL skb still has an active DMA mapping and therefore always
calls dma_unmap_single() before freeing the skb.

This assumption is not true for the monitor RX path.
ath12k_wifi7_dp_rx_mon_mpdu_pop() may DMA-unmap a buffer and mark
rxcb->unmapped before returning early to hold the MSDU for later
reprocessing. In that state desc_info->skb remains populated, so
module removal can trigger a second dma_unmap_single() from
ath12k_dp_cc_cleanup().

IOMMU reports the issue as:
  dma_unmap_phys()
  dma_unmap_page_attrs()
  ath12k_dp_cc_cleanup()
  ath12k_dp_cmn_device_deinit()
  ath12k_core_stop()

Skip dma_unmap_single() when rxcb->unmapped is already set and free
the skb directly.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c7-00108-QCAHMTSWPL_V1.0_V2.0_SILICONZ_UPSTREAM-3

Fixes: 72bfbf19b7 ("wifi: ath12k: add support to reap and process mon dest ring")
Signed-off-by: Kang Yang <kang.yang@oss.qualcomm.com>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20260916060325.854-7-kang.yang@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>

...

This commit is contained in:

Kang Yang 2026-09-16 14:03:25 +08:00 • committed by Jeff Johnson

parent 97b144b82e

commit febe1f8cbc

1 changed files with 5 additions and 4 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

9

drivers/net/wireless/ath/ath12k/dp.c

View file