From: Thomas Gleixner tglx@linutronix.de
commit 4001d8e8762f57d418b66e4e668601791900a1dd upstream.
When interrupts are shutdown, they are immediately deactivated in the irqdomain hierarchy. While this looks obviously correct there is a subtle issue:
There might be an interrupt in flight when free_irq() is invoking the shutdown. This is properly handled at the irq descriptor / primary handler level, but the deactivation might completely disable resources which are required to acknowledge the interrupt.
Split the shutdown code and deactivate the interrupt after synchronization in free_irq(). Fixup all other usage sites where this is not an issue to invoke the combined shutdown_and_deactivate() function instead.
This still might be an issue if the interrupt in flight servicing is delayed on a remote CPU beyond the invocation of synchronize_irq(), but that cannot be handled at that level and needs to be handled in the synchronize_irq() context.
Fixes: f8264e34965a ("irqdomain: Introduce new interfaces to support hierarchy irqdomains") Reported-by: Robert Hodaszi Robert.Hodaszi@digi.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Reviewed-by: Marc Zyngier marc.zyngier@arm.com Link: https://lkml.kernel.org/r/20190628111440.098196390@linutronix.de Signed-off-by: Rishabh Bhatnagar risbhat@amazon.com --- kernel/irq/autoprobe.c | 6 +++--- kernel/irq/chip.c | 6 ++++++ kernel/irq/cpuhotplug.c | 2 +- kernel/irq/internals.h | 1 + kernel/irq/manage.c | 10 ++++++++++ 5 files changed, 21 insertions(+), 4 deletions(-)
diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c index befa671fba64..39ff9ab34e82 100644 --- a/kernel/irq/autoprobe.c +++ b/kernel/irq/autoprobe.c @@ -92,7 +92,7 @@ unsigned long probe_irq_on(void) /* It triggered already - consider it spurious. */ if (!(desc->istate & IRQS_WAITING)) { desc->istate &= ~IRQS_AUTODETECT; - irq_shutdown(desc); + irq_shutdown_and_deactivate(desc); } else if (i < 32) mask |= 1 << i; @@ -129,7 +129,7 @@ unsigned int probe_irq_mask(unsigned long val) mask |= 1 << i;
desc->istate &= ~IRQS_AUTODETECT; - irq_shutdown(desc); + irq_shutdown_and_deactivate(desc); } raw_spin_unlock_irq(&desc->lock); } @@ -171,7 +171,7 @@ int probe_irq_off(unsigned long val) nr_of_irqs++; } desc->istate &= ~IRQS_AUTODETECT; - irq_shutdown(desc); + irq_shutdown_and_deactivate(desc); } raw_spin_unlock_irq(&desc->lock); } diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c index 317fc759de76..1936d86db883 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -293,6 +293,12 @@ void irq_shutdown(struct irq_desc *desc) } irq_state_clr_started(desc); } +} + + +void irq_shutdown_and_deactivate(struct irq_desc *desc) +{ + irq_shutdown(desc); /* * This must be called even if the interrupt was never started up, * because the activation can happen before the interrupt is diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c index 9eb09aef0313..a9f931217a1b 100644 --- a/kernel/irq/cpuhotplug.c +++ b/kernel/irq/cpuhotplug.c @@ -115,7 +115,7 @@ static bool migrate_one_irq(struct irq_desc *desc) */ if (irqd_affinity_is_managed(d)) { irqd_set_managed_shutdown(d); - irq_shutdown(desc); + irq_shutdown_and_deactivate(desc); return false; } affinity = cpu_online_mask; diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 5230c47fc43e..3de3821ab5fe 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -78,6 +78,7 @@ extern void __enable_irq(struct irq_desc *desc); extern int irq_startup(struct irq_desc *desc, bool resend, bool force);
extern void irq_shutdown(struct irq_desc *desc); +extern void irq_shutdown_and_deactivate(struct irq_desc *desc); extern void irq_enable(struct irq_desc *desc); extern void irq_disable(struct irq_desc *desc); extern void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 722aeaae92b1..4e4fc7879307 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -14,6 +14,7 @@ #include <linux/module.h> #include <linux/random.h> #include <linux/interrupt.h> +#include <linux/irqdomain.h> #include <linux/slab.h> #include <linux/sched.h> #include <linux/sched/rt.h> @@ -1604,6 +1605,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) /* If this was the last handler, shut down the IRQ line: */ if (!desc->action) { irq_settings_clr_disable_unlazy(desc); + /* Only shutdown. Deactivate after synchronize_hardirq() */ irq_shutdown(desc); }
@@ -1673,6 +1675,14 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id) * require it to deallocate resources over the slow bus. */ chip_bus_lock(desc); + /* + * There is no interrupt on the fly anymore. Deactivate it + * completely. + */ + raw_spin_lock_irqsave(&desc->lock, flags); + irq_domain_deactivate_irq(&desc->irq_data); + raw_spin_unlock_irqrestore(&desc->lock, flags); + irq_release_resources(desc); chip_bus_sync_unlock(desc); irq_remove_timings(desc);