In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix dead lock while flushing management frames
Commit [1] converted the management transmission work item into a wiphy work. Since a wiphy work can only run under wiphy lock protection, a race condition happens in below scenario:
- a management frame is queued for transmission.
- ath12k_mac_op_flush() gets called to flush pending frames associated
- Since wiphy lock has been taken by the flush process, the transmission
>From user view, this dead lock results in below issue:
wlp8s0: authenticate with xxxxxx (local address=xxxxxx) wlp8s0: send auth to xxxxxx (try 1/3) wlp8s0: authenticate with xxxxxx (local address=xxxxxx) wlp8s0: send auth to xxxxxx (try 1/3) wlp8s0: authenticated wlp8s0: associate with xxxxxx (try 1/3) wlp8s0: aborting association with xxxxxx by local choice (Reason: 3=DEAUTH_LEAVING) ath12k_pci 0000:08:00.0: failed to flush mgmt transmit queue, mgmt pkts pending 1
The dead lock can be avoided by invoking wiphy_work_flush() to proactively run the queued work item. Note actually it is already present in ath12k_mac_op_flush(), however it does not protect the case where vif being NULL. Hence move it ahead to cover this case as well.
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3