On 08/25/2017 05:14 AM, Dan Carpenter wrote:
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
earlier.
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Thanks for identifying and fixing this. It looks plausible, so if it
compiles without error you can add:
Acked-by: David Daney <david.daney@xxxxxxxxxx>
---
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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