zhichen@xxxxxxxxxxxxxx wrote: > 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@xxxxxxxxxxxxxx> > Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> 2 patches applied to ath-next branch of ath.git, thanks. 2d3b55853b12 ath10k: fix peer stats null pointer dereference 386f97e3b201 ath10k: fix tx_stats memory leak -- https://patchwork.kernel.org/patch/10722983/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
