[ Upstream commit 2d3b55853b ]
There was a race condition in SMP that an ath10k_peer was created but its
member sta was null. Following are procedures of ath10k_peer creation and
member sta access in peer statistics path.
1. Peer creation:
ath10k_peer_create()
=>ath10k_wmi_peer_create()
=>ath10k_wait_for_peer_created()
...
# another kernel path, RX from firmware
ath10k_htt_t2h_msg_handler()
=>ath10k_peer_map_event()
=>wake_up()
# ar->peer_map[id] = peer //add peer to map
#wake up original path from waiting
...
# peer->sta = sta //sta assignment
2. RX path of statistics
ath10k_htt_t2h_msg_handler()
=>ath10k_update_per_peer_tx_stats()
=>ath10k_htt_fetch_peer_stats()
# peer->sta //sta accessing
Any access of peer->sta after peer was added to peer_map but before sta was
assigned could cause a null pointer issue. And because these two steps are
asynchronous, no proper lock can protect them. So both peer and sta need to
be checked before access.
Tested: QCA9984 with firmware ver 10.4-3.9.0.1-00005
Signed-off-by: Zhi Chen <zhichen@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
0718a466c6