This is a note to let you know that I've just added the patch titled irq: mips: avoid nested irq_enter() to the 5.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: irq-mips-avoid-nested-irq_enter.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 748cc0c40f1b87585636acad27dc7b0f101d4d9a Author: Mark Rutland <mark.rutland@xxxxxxx> Date: Wed Oct 20 17:25:22 2021 +0100 irq: mips: avoid nested irq_enter() [ Upstream commit c65b52d02f6c1a06ddb20cba175ad49eccd6410d ] As bcm6345_l1_irq_handle() is a chained irqchip handler, it will be invoked within the context of the root irqchip handler, which must have entered IRQ context already. When bcm6345_l1_irq_handle() calls arch/mips's do_IRQ() , this will nest another call to irq_enter(), and the resulting nested increment to `rcu_data.dynticks_nmi_nesting` will cause rcu_is_cpu_rrupt_from_idle() to fail to identify wakeups from idle, resulting in failure to preempt, and RCU stalls. Chained irqchip handlers must invoke IRQ handlers by way of thee core irqchip code, i.e. generic_handle_irq() or generic_handle_domain_irq() and should not call do_IRQ(), which is intended only for root irqchip handlers. Fix bcm6345_l1_irq_handle() by calling generic_handle_irq() directly. Fixes: c7c42ec2baa1de7a ("irqchips/bmips: Add bcm6345-l1 interrupt controller") Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx> Acked-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/irqchip/irq-bcm6345-l1.c b/drivers/irqchip/irq-bcm6345-l1.c index e3483789f4df3..1bd0621c4ce2a 100644 --- a/drivers/irqchip/irq-bcm6345-l1.c +++ b/drivers/irqchip/irq-bcm6345-l1.c @@ -140,7 +140,7 @@ static void bcm6345_l1_irq_handle(struct irq_desc *desc) for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) { irq = irq_linear_revmap(intc->domain, base + hwirq); if (irq) - do_IRQ(irq); + generic_handle_irq(irq); else spurious_interrupt(); }