[PATCH 5.18 268/879] ath11k: acquire ab->base_lock in unassign when finding the peer by addr

Greg Kroah-Hartman
2022-06-07T22:29:51Z

From: Niels Dossche <dossche.niels@gmail.com>

[ Upstream commit 2db80f93869d491be57cbc2b36f30d0d3a0e5bde ]

ath11k_peer_find_by_addr states via lockdep that ab->base_lock must be
held when calling that function in order to protect the list. All
callers except ath11k_mac_op_unassign_vif_chanctx have that lock
acquired when calling ath11k_peer_find_by_addr. That lock is also not
transitively held by a path towards ath11k_mac_op_unassign_vif_chanctx.
The solution is to acquire the lock when calling
ath11k_peer_find_by_addr inside ath11k_mac_op_unassign_vif_chanctx.

I am currently working on a static analyser to detect missing locks and
this was a reported case. I manually verified the report by looking at
the code, but I do not have real hardware so this is compile tested
only.

Fixes: 701e48a43e15 ("ath11k: add packet log support for QCA6390")
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220314215253.92658-1-dossche.niels@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/ath/ath11k/mac.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 58ff761393db..2c8d5f2a0517 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -7114,6 +7114,7 @@ ath11k_mac_op_unassign_vif_chanctx(struct ieee80211_hw *hw,
struct ath11k *ar = hw->priv;
struct ath11k_base *ab = ar->ab;
struct ath11k_vif *arvif = (void *)vif->drv_priv;
+ struct ath11k_peer *peer;
int ret;

mutex_lock(&ar->conf_mutex);
@@ -7125,9 +7126,13 @@ ath11k_mac_op_unassign_vif_chanctx(struct ieee80211_hw *hw,
WARN_ON(!arvif->is_started);

if (ab->hw_params.vdev_start_delay &&
- arvif->vdev_type == WMI_VDEV_TYPE_MONITOR &&
- ath11k_peer_find_by_addr(ab, ar->mac_addr))
- ath11k_peer_delete(ar, arvif->vdev_id, ar->mac_addr);
+ arvif->vdev_type == WMI_VDEV_TYPE_MONITOR) {
+ spin_lock_bh(&ab->base_lock);
+ peer = ath11k_peer_find_by_addr(ab, ar->mac_addr);
+ spin_unlock_bh(&ab->base_lock);
+ if (peer)
+ ath11k_peer_delete(ar, arvif->vdev_id, ar->mac_addr);
+ }

if (arvif->vdev_type == WMI_VDEV_TYPE_MONITOR) {
ret = ath11k_mac_monitor_stop(ar);
--
2.35.1