From 409596462aafb62c4f034a8d1f92433d3db0f698 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 31 May 2017 11:58:33 +0200 Subject: [PATCH] UPSTREAM: genirq: Warn when IRQ_NOAUTOEN is used with shared interrupts Shared interrupts do not go well with disabling auto enable: 1) The sharing interrupt might request it while it's still disabled and then wait for interrupts forever. 2) The interrupt might have been requested by the driver sharing the line before IRQ_NOAUTOEN has been set. So the driver which expects that disabled state after calling request_irq() will not get what it wants. Even worse, when it calls enable_irq() later, it will trigger the unbalanced enable_irq() warning. Reported-by: Brian Norris Signed-off-by: Thomas Gleixner Cc: dianders@chromium.org Cc: jeffy Cc: Marc Zyngier Cc: tfiga@chromium.org Link: http://lkml.kernel.org/r/20170531100212.210682135@linutronix.de (cherry picked from commit 04c848d398797a626608ff48804d809ae6687163) Change-Id: I89711656f22e15697c76a4dcb9c60c8b0c8052d2 Signed-off-by: Jeffy Chen --- kernel/irq/chip.c | 7 +++++++ kernel/irq/manage.c | 12 ++++++++++-- 2 files changed, 17 insertions(+), 2 deletions(-) diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 481b9a2ee690..e0190c9662c5 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -865,6 +865,13 @@ void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set) if (!desc) return; + + /* + * Warn when a driver sets the no autoenable flag on an already + * active interrupt. + */ + WARN_ON_ONCE(!desc->depth && (set & _IRQ_NOAUTOEN)); + irq_settings_clr_and_set(desc, clr, set); irqd_clear(&desc->irq_data, IRQD_NO_BALANCING | IRQD_PER_CPU | diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 8755e74d0238..cee102969d08 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1311,11 +1311,19 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) if (new->flags & IRQF_ONESHOT) desc->istate |= IRQS_ONESHOT; - if (irq_settings_can_autoenable(desc)) + if (irq_settings_can_autoenable(desc)) { irq_startup(desc, true); - else + } else { + /* + * Shared interrupts do not go well with disabling + * auto enable. The sharing interrupt might request + * it while it's still disabled and then wait for + * interrupts forever. + */ + WARN_ON_ONCE(new->flags & IRQF_SHARED); /* Undo nested disables: */ desc->depth = 1; + } /* Exclude IRQ from balancing if requested */ if (new->flags & IRQF_NOBALANCING) {