CVE-2022-50700CVE-2022-50700

In the Linux kernel, the following vulnerability has been resolved: wifi: ath10k: Delay the unmapping of the buffer On WCN3990, we are seeing a rare scenario where copy engine hardware is sending a copy complete interrupt to the host driver while still processing the buffer that the driver has sent, this is leading into an SMMU fault triggering kernel panic. This is happening on copy engine channel 3 (CE3) where the driver normally enqueues WMI commands to the firmware. Upon receiving a copy complete interrupt, host driver will immediately unmap and frees the buffer presuming that hardware has processed the buffer. In the issue case, upon receiving copy complete interrupt, host driver will unmap and free the buffer but since hardware is still accessing the buffer (which in this case got unmapped in parallel), SMMU hardware will trigger an SMMU fault resulting in a kernel panic. In order to avoid this, as a work around, add a delay before unmapping the copy engine source DMA buffer.