Otherwise, with CONFIG_DEBUG_SPINLOCK=y, this stack trace gets printed
when enabling RX timestamping and receiving a PTP frame:

[  318.537078] INFO: trying to register non-static key.
[  318.542040] the code is fine but needs lockdep annotation.
[  318.547500] turning off the locking correctness validator.
[  318.552972] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.3.0-13257-g0825b0669811-dirty #1962
[  318.561283] Hardware name: Freescale LS1021A
[  318.565566] [<c03144bc>] (unwind_backtrace) from [<c030e164>] (show_stack+0x10/0x14)
[  318.573289] [<c030e164>] (show_stack) from [<c11b9f50>] (dump_stack+0xd4/0x100)
[  318.580579] [<c11b9f50>] (dump_stack) from [<c03b9b40>] (register_lock_class+0x728/0x734)
[  318.588731] [<c03b9b40>] (register_lock_class) from [<c03b60c4>] (__lock_acquire+0x78/0x25cc)
[  318.597227] [<c03b60c4>] (__lock_acquire) from [<c03b8ef8>] (lock_acquire+0xd8/0x234)
[  318.605033] [<c03b8ef8>] (lock_acquire) from [<c11db934>] (_raw_spin_lock+0x44/0x54)
[  318.612755] [<c11db934>] (_raw_spin_lock) from [<c1164370>] (sja1105_rcv+0x1f8/0x4e8)
[  318.620561] [<c1164370>] (sja1105_rcv) from [<c115d7cc>] (dsa_switch_rcv+0x80/0x204)
[  318.628283] [<c115d7cc>] (dsa_switch_rcv) from [<c0f58c80>] (__netif_receive_skb_one_core+0x50/0x6c)
[  318.637386] [<c0f58c80>] (__netif_receive_skb_one_core) from [<c0f58f04>] (netif_receive_skb_internal+0xac/0x264)
[  318.647611] [<c0f58f04>] (netif_receive_skb_internal) from [<c0f59e98>] (napi_gro_receive+0x1d8/0x338)
[  318.656887] [<c0f59e98>] (napi_gro_receive) from [<c0c298a4>] (gfar_clean_rx_ring+0x328/0x724)
[  318.665472] [<c0c298a4>] (gfar_clean_rx_ring) from [<c0c29e60>] (gfar_poll_rx_sq+0x34/0x94)
[  318.673795] [<c0c29e60>] (gfar_poll_rx_sq) from [<c0f5b40c>] (net_rx_action+0x128/0x4f8)
[  318.681860] [<c0f5b40c>] (net_rx_action) from [<c03022f0>] (__do_softirq+0x148/0x5ac)
[  318.689666] [<c03022f0>] (__do_softirq) from [<c0355af4>] (irq_exit+0x160/0x170)
[  318.697040] [<c0355af4>] (irq_exit) from [<c03c6818>] (__handle_domain_irq+0x60/0xb4)
[  318.704847] [<c03c6818>] (__handle_domain_irq) from [<c07e9440>] (gic_handle_irq+0x58/0x9c)
[  318.713172] [<c07e9440>] (gic_handle_irq) from [<c0301a70>] (__irq_svc+0x70/0x98)
[  318.720622] Exception stack(0xc2001f18 to 0xc2001f60)
[  318.725656] 1f00:                                                       00000001 00000006
[  318.733805] 1f20: 00000000 c20165c0 ffffe000 c2010cac c2010cf4 00000001 00000000 c2010c88
[  318.741955] 1f40: c1f7a5a8 00000000 00000000 c2001f68 c03ba140 c030a288 200e0013 ffffffff
[  318.750110] [<c0301a70>] (__irq_svc) from [<c030a288>] (arch_cpu_idle+0x24/0x3c)
[  318.757486] [<c030a288>] (arch_cpu_idle) from [<c038a480>] (do_idle+0x1b8/0x2a4)
[  318.764859] [<c038a480>] (do_idle) from [<c038a94c>] (cpu_startup_entry+0x18/0x1c)
[  318.772407] [<c038a94c>] (cpu_startup_entry) from [<c1e00f10>] (start_kernel+0x4cc/0x4fc)

Fixes: 844d7edc

 ("net: dsa: sja1105: Add a global sja1105_tagger_data structure")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>