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Subject[PATCH v3] irqdomain: Prevent Oops in irq_domain_push_irq()
This code generates a Smatch warning:

kernel/irq/irqdomain.c:1511 irq_domain_push_irq()
warn: variable dereferenced before check 'root_irq_data' (see line 1508)

irq_get_irq_data() does sometimes return NULL pointers so this seems
like a real bug. Let's fix this bug by moving the check for NULL

Signed-off-by: Dan Carpenter <>
v2: Redo changelog.
v3: Redo changelog again. Make it imperative.

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index b9c688944429..e84b7056bb08 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1505,10 +1505,10 @@ int irq_domain_push_irq(struct irq_domain *domain, int virq, void *arg)
if (WARN_ON(!irq_domain_is_hierarchy(domain)))
return -EINVAL;

- if (domain->parent != root_irq_data->domain)
+ if (!root_irq_data)
return -EINVAL;

- if (!root_irq_data)
+ if (domain->parent != root_irq_data->domain)
return -EINVAL;

child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL,
 \ /
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