From 4001d8e8762f57d418b66e4e668601791900a1dd Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 28 Jun 2019 13:11:49 +0200 Subject: [PATCH] genirq: Delay deactivation in free_irq() 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 Signed-off-by: Thomas Gleixner Reviewed-by: Marc Zyngier Link: https://lkml.kernel.org/r/20190628111440.098196390@linutronix.de --- kernel/irq/autoprobe.c | 6 +++--- kernel/irq/chip.c | 6 ++++++ kernel/irq/cpuhotplug.c | 2 +- kernel/irq/internals.h | 1 + kernel/irq/manage.c | 12 +++++++++++- 5 files changed, 22 insertions(+), 5 deletions(-) diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c index 16cbf6beb276..ae60cae24e9a 100644 --- a/kernel/irq/autoprobe.c +++ b/kernel/irq/autoprobe.c @@ -90,7 +90,7 @@ 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; @@ -127,7 +127,7 @@ 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); } @@ -169,7 +169,7 @@ 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 51128bea3846..04fe4f989bd8 100644 --- a/kernel/irq/chip.c +++ b/kernel/irq/chip.c @@ -314,6 +314,12 @@ 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 5b1072e394b2..6c7ca2e983a5 100644 --- a/kernel/irq/cpuhotplug.c +++ b/kernel/irq/cpuhotplug.c @@ -116,7 +116,7 @@ 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 70c3053bc1f6..9c957f8b1198 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h @@ -82,6 +82,7 @@ extern int irq_activate_and_startup(struct irq_desc *desc, bool resend); 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 53a081392115..dc8b35f2d545 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -1699,6 +1700,7 @@ static struct irqaction *__free_irq(struct irq_desc *desc, 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); } @@ -1768,6 +1770,14 @@ static struct irqaction *__free_irq(struct irq_desc *desc, 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); @@ -1855,7 +1865,7 @@ static const void *__cleanup_nmi(unsigned int irq, struct irq_desc *desc) } irq_settings_clr_disable_unlazy(desc); - irq_shutdown(desc); + irq_shutdown_and_deactivate(desc); irq_release_resources(desc);