Fixes a reported lockdep error in mac80211:
[ 179.867321] =============================
[ 179.871510] WARNING: suspicious RCU usage
[ 179.875528] 4.14.32 #0 Not tainted
[ 179.878924] -----------------------------
[ 179.882981] backports-2017-11-01/net/mac80211/tx.c:594 suspicious rcu_dereference_check() usage!
[ 179.891785]
[ 179.891785] other info that might help us debug this:
[ 179.891785]
[ 179.899824]
[ 179.899824] rcu_scheduler_active = 2, debug_locks = 1
[ 179.906343] 2 locks held by ksoftirqd/0/7:
[ 179.910479] #0: (&(&q->lock)->rlock){+.-.}, at: [<86b207a4>] mt76_dma_tx_cleanup+0x64/0x354 [mt76]
[ 179.919734] #1: (&(&fq->lock)->rlock){+.-.}, at: [<87238410>] ieee80211_tx_dequeue+0x54/0xc3c [mac80211]
[ 179.929890]
[ 179.929890] stack backtrace:
[ 179.934257] CPU: 0 PID: 7 Comm: ksoftirqd/0 Not tainted 4.14.32 #0
[ 179.940421] Stack : 00000000 00000000 00000000 00000000 80e0fce2 00000036 00000000 00000000
[ 179.948864] 87c3d24c 80696377 8061039c 00000000 00000007 00000001 87c5db78 6534689d
[ 179.957306] 00000000 00000000 80e10000 87c5da74 00000001 0000015a 00000007 00000000
[ 179.965748] 00000000 806a0000 000e4171 00000000 00000000 00000000 ffffffff 00000001
[ 179.974189] 806c0000 8692b240 86b000d0 87316fe4 00000001 802c9a68 00000000 80700000
[ 179.982632] ...
[ 179.985104] Call Trace:
[ 179.987582] [<80010a48>] show_stack+0x58/0x100
[ 179.992040] [<804c2c58>] dump_stack+0xe8/0x170
[ 179.996868] [<87234a04>] ieee80211_tx_h_select_key+0xa8/0x5b8 [mac80211]
[ 180.004299] [<87238d44>] ieee80211_tx_dequeue+0x988/0xc3c [mac80211]
[ 180.011048] [<86b230dc>] mt76_txq_schedule+0x110/0x3a4 [mt76]
[ 180.016821] [<86b209d0>] mt76_dma_tx_cleanup+0x290/0x354 [mt76]
[ 180.022777] [<86be2e60>] mt7603_tx_tasklet+0x40/0x6c [mt7603e]
[ 180.028637] [<80037058>] tasklet_action+0x110/0x1ec
[ 180.033532] [<804e1dac>] __do_softirq+0x164/0x35c
[ 180.038235] [<80037174>] run_ksoftirqd+0x40/0x84
[ 180.042870] [<800580c8>] smpboot_thread_fn+0x1a8/0x1d8
[ 180.048023] [<800542e8>] kthread+0x130/0x144
[ 180.052297] [<8000b1f8>] ret_from_kernel_thread+0x14/0x1c
Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
---
drivers/net/wireless/mediatek/mt76/tx.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/wireless/mediatek/mt76/tx.c b/drivers/net/wireless/mediatek/mt76/tx.c
index 4eef69bd8a9e..6aca794cf998 100644
--- a/drivers/net/wireless/mediatek/mt76/tx.c
+++ b/drivers/net/wireless/mediatek/mt76/tx.c
@@ -422,12 +422,14 @@ void mt76_txq_schedule(struct mt76_dev *dev, struct mt76_queue *hwq)
{
int len;
+ rcu_read_lock();
do {
if (hwq->swq_queued >= 4 || list_empty(&hwq->swq))
break;
len = mt76_txq_schedule_list(dev, hwq);
} while (len > 0);
+ rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(mt76_txq_schedule);
--
2.14.2
