From: Alexander Sverdlin alexander.sverdlin@nokia.com

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@nokia.com Reported-by: Tomasz Bachorski tomasz.bachorski@nokia.com Reported-by: Wojciech Kosnikowski wojciech.kosnikowski@nokia.com Cc: stable@vger.kernel.org Signed-off-by: Alexander Sverdlin alexander.sverdlin@nokia.com --- 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) {