softirq: Add debug check to __raise_softirq_irqoff()

__raise_softirq_irqoff() must be called with interrupts disabled to protect
the per CPU softirq pending state update against an interrupt and soft
interrupt handling on return from interrupt.

Add a lockdep assertion to validate the calling convention.

[ tglx: Massaged changelog ]

Signed-off-by: Jiafei Pan <Jiafei.Pan@nxp.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20200814045522.45719-1-Jiafei.Pan@nxp.com

kernel/softirq.c

@@ -481,6 +481,7 @@ void raise_softirq(unsigned int nr)
 
 void __raise_softirq_irqoff(unsigned int nr)
 {
+	lockdep_assert_irqs_disabled();
 	trace_softirq_raise(nr);
 	or_softirq_pending(1UL << nr);
 }