This is a note to let you know that I've just added the patch titled
mt76: mt7921: fix a leftover race in runtime-pm
to the 5.17-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mt76-mt7921-fix-a-leftover-race-in-runtime-pm.patch
and it can be found in the queue-5.17 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9d64c081691ec21ffd400cd9e59b5bc3bd372d24
Author: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Date: Thu Dec 30 21:47:05 2021 +0100
mt76: mt7921: fix a leftover race in runtime-pm
[ 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>
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
index ec10f95a4649..3e83a0c33143 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mac.c
@@ -1551,6 +1551,14 @@ 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;
