From 09cccf2f21d14f5ed2e114c7372031eb14209999 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <>
Date: Wed, 16 Sep 2020 16:15:39 +0200
Subject: [PATCH 106/166] net: Dequeue in dev_cpu_dead() without the lock

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 <>
Signed-off-by: Thomas Gleixner <>
 net/core/dev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-5.15.13-rt26/net/core/dev.c
@ linux-5.15.13-rt26/net/core/dev.c:11335 @ static int dev_cpu_dead(unsigned int old
-	while ((skb = skb_dequeue(&oldsd->input_pkt_queue))) {
+	while ((skb = __skb_dequeue(&oldsd->input_pkt_queue))) {