genirq/irqdomain: Don't try to free an interrupt that has no mapping

[ Upstream commit 4615fbc3788ddc8e7c6d697714ad35a53729aa2c ]

When an interrupt allocation fails for N interrupts, it is pretty
common for the error handling code to free the same number of interrupts,
no matter how many interrupts have actually been allocated.

This may result in the domain freeing code to be unexpectedly called
for interrupts that have no mapping in that domain. Things end pretty
badly.

Instead, add some checks to irq_domain_free_irqs_hierarchy() to make sure
that thiss does not follow the hierarchy if no mapping exists for a given
interrupt.

Fixes: 6a6544e520abe ("genirq/irqdomain: Remove auto-recursive hierarchy support")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201129135551.396777-1-maz@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 0a76c44eb6b29e0d778b7d95a6286e00ad506a0e..1e42fc2ad4d57a3a752e238964c0cdc38d810e08 100644 (file)
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1247,8 +1247,15 @@ static void irq_domain_free_irqs_hierarchy(struct irq_domain *domain,
                                           unsigned int irq_base,
                                           unsigned int nr_irqs)
 {
-       if (domain->ops->free)
-               domain->ops->free(domain, irq_base, nr_irqs);
+       unsigned int i;
+
+       if (!domain->ops->free)
+               return;
+
+       for (i = 0; i < nr_irqs; i++) {
+               if (irq_domain_get_irq_data(domain, irq_base + i))
+                       domain->ops->free(domain, irq_base + i, 1);
+       }
 }
 
 int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,