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;