From 95dbb10c81619c9a35a63f73dadd7379d95fdec0 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 16 Sep 2020 16:15:39 +0200
Subject: [PATCH 237/323] net: Dequeue in dev_cpu_dead() without the lock
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz

Upstream uses skb_dequeue() to acquire lock of `input_pkt_queue'. The reason is
to synchronize against a remote CPU which still thinks that the CPU is online
enqueues packets to this CPU.
There are no guarantees that the packet is enqueued before the callback is run,
it just hope.
RT however complains about an not initialized lock because it uses another lock
for `input_pkt_queue' due to the IRQ-off nature of the context.

Use the unlocked dequeue version for `input_pkt_queue'.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 net/core/dev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index 895eb42bb5d6..c55993848233 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10980,7 +10980,7 @@ static int dev_cpu_dead(unsigned int oldcpu)
 		netif_rx_ni(skb);
 		input_queue_head_incr(oldsd);
 	}
-	while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
+	while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {
 		netif_rx_ni(skb);
 		input_queue_head_incr(oldsd);
 	}
-- 
2.43.0