From: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
[ Upstream commit 591cdccebdd4d02eb46d400dea911136400cc567 ]
Fix a possible race in mt7921_pm_power_save_work() if rx/tx napi
schedules ps_work and we are currently accessing device register
on a different cpu.
Fixes: 1d8efc741df8 ("mt76: mt7921: introduce Runtime PM support")
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/wireless/mediatek/mt76/mt7921/mac.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index fc21a78b37c4..1fea9266d4b8 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -1472,6 +1472,14 @@ void mt7921_pm_power_save_work(struct work_struct *work)
test_bit(MT76_HW_SCHED_SCANNING, &mphy->state))
goto out;
+ if (mutex_is_locked(&dev->mt76.mutex))
+ /* if mt76 mutex is held we should not put the device
+ * to sleep since we are currently accessing device
+ * register map. We need to wait for the next power_save
+ * trigger.
+ */
+ goto out;
+
if (time_is_after_jiffies(dev->pm.last_activity + delta)) {
delta = dev->pm.last_activity + delta - jiffies;
goto out;
--
2.34.1
