From: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
irq_domain_associate() is the only place where irq_find_mapping() can be
used reliably (under irq_domain_mutex) to make a decision if the mapping
shall be created or not. Other calls to irq_find_mapping() (not under
any lock) cannot be used for this purpose and lead to race conditions in
particular inside irq_create_mapping().
Give the callers of irq_domain_associate() an ability to detect existing
domain reliably by examining the return value.
Reported-by: Krzysztof Adamski <krzysztof.adamski@xxxxxxxxx>
Reported-by: Tomasz Bachorski <tomasz.bachorski@xxxxxxxxx>
Reported-by: Wojciech Kosnikowski <wojciech.kosnikowski@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Alexander Sverdlin <alexander.sverdlin@xxxxxxxxx>
---
kernel/irq/irqdomain.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 132672b..ccbb048 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -545,6 +545,15 @@ int irq_domain_associate(struct irq_domain *domain, unsigned int virq,
return -EINVAL;
mutex_lock(&irq_domain_mutex);
+
+ /* Check if mapping already exists */
+ if (irq_find_mapping(domain, hwirq)) {
+ mutex_unlock(&irq_domain_mutex);
+ pr_debug("%s: conflicting mapping for hwirq 0x%x\n",
+ domain->name, (int)hwirq);
+ return -EEXIST;
+ }
+
irq_data->hwirq = hwirq;
irq_data->domain = domain;
if (domain->ops->map) {
--
2.4.6
