4.20-stable review patch. If anyone has any objections, please let me know.
------------------
[ 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@xxxxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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;
--
2.19.1
