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authorThomas Gleixner <tglx@linutronix.de>2019-06-23 20:04:32 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-06-28 13:19:17 +0200
commitbd62f444b98d511e7ee9e66c57c082c026230ab7 (patch)
tree5c1f6ecf3f1d98d1697814317ab17f0d7cde1a79 /kernel/irq/manage.c
parent4b972a01a7da614b4796475f933094751a295a2f (diff)
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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 <Robert.Hodaszi@digi.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'kernel/irq/manage.c')
-rw-r--r--kernel/irq/manage.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 78f3ddeb7fe4..54a41da65eb3 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -13,6 +13,7 @@
#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>
@@ -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);