From: Alexander Sverdlin alexander.sverdlin@nokia.com

If two irq_create_mapping() calls perform a mapping of the same hwirq on two CPU cores in parallel they both will get 0 from irq_find_mapping(), both will allocate unique virq using irq_domain_alloc_descs() and both will finally irq_domain_associate() it. Giving different virq numbers to their callers.

In practice the first caller is usually an interrupt controller driver and the seconds is some device requesting the interrupt providede by the above interrupt controller.

In this case either the interrupt controller driver configures virq which is not the one being "associated" with hwirq, or the "slave" device requests the virq which is never being triggered.

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 | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index ccbb048..ad62c08 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -661,6 +661,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain, { struct device_node *of_node; int virq; + int ret;

pr_debug("irq_create_mapping(0x%p, 0x%lx)\n", domain, hwirq);

@@ -675,13 +676,6 @@ unsigned int irq_create_mapping(struct irq_domain *domain,

of_node = irq_domain_get_of_node(domain);

- /* Check if mapping already exists */ - virq = irq_find_mapping(domain, hwirq); - if (virq) { - pr_debug("-> existing mapping on virq %d\n", virq); - return virq; - } - /* Allocate a virtual interrupt number */ virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node), NULL); if (virq <= 0) { @@ -689,8 +683,11 @@ unsigned int irq_create_mapping(struct irq_domain *domain, return 0; }

- if (irq_domain_associate(domain, virq, hwirq)) { + ret = irq_domain_associate(domain, virq, hwirq); + if (ret) { irq_free_desc(virq); + if (ret == -EEXIST) + return irq_find_mapping(domain, hwirq); return 0; }