4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 2d3b55853b123c177037cf534c5aaa2650310094 ]
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 --- drivers/net/wireless/ath/ath10k/debugfs_sta.c | 2 +- drivers/net/wireless/ath/ath10k/htt_rx.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/ath/ath10k/debugfs_sta.c b/drivers/net/wireless/ath/ath10k/debugfs_sta.c index b09cdc699c69..38afbbd9fb44 100644 --- a/drivers/net/wireless/ath/ath10k/debugfs_sta.c +++ b/drivers/net/wireless/ath/ath10k/debugfs_sta.c @@ -71,7 +71,7 @@ void ath10k_sta_update_rx_tid_stats_ampdu(struct ath10k *ar, u16 peer_id, u8 tid spin_lock_bh(&ar->data_lock);
peer = ath10k_peer_find_by_id(ar, peer_id); - if (!peer) + if (!peer || !peer->sta) goto out;
arsta = (struct ath10k_sta *)peer->sta->drv_priv; diff --git a/drivers/net/wireless/ath/ath10k/htt_rx.c b/drivers/net/wireless/ath/ath10k/htt_rx.c index ffec98f7be50..2c2761d04d01 100644 --- a/drivers/net/wireless/ath/ath10k/htt_rx.c +++ b/drivers/net/wireless/ath/ath10k/htt_rx.c @@ -2832,7 +2832,7 @@ static void ath10k_htt_fetch_peer_stats(struct ath10k *ar, rcu_read_lock(); spin_lock_bh(&ar->data_lock); peer = ath10k_peer_find_by_id(ar, peer_id); - if (!peer) { + if (!peer || !peer->sta) { ath10k_warn(ar, "Invalid peer id %d peer stats buffer\n", peer_id); goto out; @@ -2885,7 +2885,7 @@ static void ath10k_fetch_10_2_tx_stats(struct ath10k *ar, u8 *data) rcu_read_lock(); spin_lock_bh(&ar->data_lock); peer = ath10k_peer_find_by_id(ar, peer_id); - if (!peer) { + if (!peer || !peer->sta) { ath10k_warn(ar, "Invalid peer id %d in peer stats buffer\n", peer_id); goto out;