From: Yicong Yang <yangyicong@hisilicon.com> The introduce of FEAT_NMI/FEAT_GICv3_NMI will cause a race problem that we may handle the normal interrupt in interrupt disabled context due to the withdraw of NMI interrupt. The flow will be like below: [interrupt disabled] <- normal interrupt pending, for example timer interrupt <- NMI occurs, ISR_EL1.nmi = 1 do_el1_interrupt() <- NMI withdraw, ISR_EL1.nmi = 0 ISR_EL1.nmi = 0, not an NMI interrupt gic_handle_irq() __gic_handle_irq_from_irqson() irqnr = gic_read_iar() <- Oops, ack and handle an normal interrupt in interrupt disabled context! Fix this by checking the interrupt status in __gic_handle_irq_from_irqson() and ignore the interrupt if we're in interrupt disabled context. Fixes: 0408b5bc4300 ("irqchip/gic-v3: Implement FEAT_GICv3_NMI support") Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> --- drivers/irqchip/irq-gic-v3.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c index c4503951b6b7..e83b24e2fad8 100644 --- a/drivers/irqchip/irq-gic-v3.c +++ b/drivers/irqchip/irq-gic-v3.c @@ -736,6 +736,28 @@ static void __gic_handle_irq_from_irqson(struct pt_regs *regs) bool is_nmi; u32 irqnr; + /* + * We should enter here with interrupts disabled, otherwise we may met + * a race here with FEAT_NMI/FEAT_GICv3_NMI: + * + * [interrupt disabled] + * <- normal interrupt pending, for example timer interrupt + * <- NMI occurs, ISR_EL1.nmi = 1 + * do_el1_interrupt() + * <- NMI withdraw, ISR_EL1.nmi = 0 + * ISR_EL1.nmi = 0, not an NMI interrupt + * gic_handle_irq() + * __gic_handle_irq_from_irqson() + * irqnr = gic_read_iar() <- Oops, ack and handle an normal interrupt + * in interrupt disabled context! + * + * So if we met this case here, just return from the interrupt context. + * Since the interrupt is still pending, we can handle it once the + * interrupt re-enabled and it'll not be missing. + */ + if (!interrupts_enabled(regs)) + return; + irqnr = gic_read_iar(); is_nmi = gic_rpr_is_nmi_prio(); -- 2.25.1