From: Alexander Sverdlin alexander.sverdlin@nokia.com

irq_create_fwspec_mapping() can race with itself during IRQ trigger type configuration. Possible scenarios include:

- Mapping exists, two irq_create_fwspec_mapping() running in parallel do not detect type mismatch, IRQ remains configured with one of the different trigger types randomly - Second call to irq_create_fwspec_mapping() sees existing mapping just created by first call, but earlier irqd_set_trigger_type() call races with later irqd_set_trigger_type() => totally undetected, IRQ type is being set randomly to either one or another type

Introduce helper function to detect parallel changes to IRQ type.

Cc: stable@vger.kernel.org Signed-off-by: Alexander Sverdlin alexander.sverdlin@nokia.com --- kernel/irq/irqdomain.c | 66 +++++++++++++++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 28 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 176f2cc..af4d30c 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -764,10 +764,45 @@ static void of_phandle_args_to_fwspec(struct device_node *np, const u32 *args, fwspec->param[i] = args[i]; }

+/* Detect races during IRQ type setting */ +static int irq_set_trigger_type_locked(unsigned int virq, unsigned int type, + irq_hw_number_t hwirq, + const struct irq_fwspec *fwspec) +{ + struct irq_data *irq_data; + int ret = 0; + + mutex_lock(&irq_domain_mutex); + /* + * If the trigger type is not specified or matches the current trigger + * type then we are done. + */ + if (type == IRQ_TYPE_NONE || type == irq_get_trigger_type(virq)) + goto unlock; + + /* If the trigger type has not been set yet, then set it now */ + if (irq_get_trigger_type(virq) != IRQ_TYPE_NONE) { + pr_warn("type mismatch, failed to map hwirq-%lu for %s!\n", + hwirq, of_node_full_name(to_of_node(fwspec->fwnode))); + ret = -EINVAL; + goto unlock; + } + + irq_data = irq_get_irq_data(virq); + if (!irq_data) { + ret = -ENOENT; + goto unlock; + } + irqd_set_trigger_type(irq_data, type); + +unlock: + mutex_unlock(&irq_domain_mutex); + return ret; +} + unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) { struct irq_domain *domain; - struct irq_data *irq_data; irq_hw_number_t hwirq; unsigned int type = IRQ_TYPE_NONE; int virq; @@ -802,29 +837,8 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) */ virq = irq_find_mapping(domain, hwirq); if (virq) { - /* - * If the trigger type is not specified or matches the - * current trigger type then we are done so return the - * interrupt number. - */ - if (type == IRQ_TYPE_NONE || type == irq_get_trigger_type(virq)) - return virq; - - /* - * If the trigger type has not been set yet, then set - * it now and return the interrupt number. - */ - if (irq_get_trigger_type(virq) == IRQ_TYPE_NONE) { - irq_data = irq_get_irq_data(virq); - if (!irq_data) - return 0; - - irqd_set_trigger_type(irq_data, type); + if (!irq_set_trigger_type_locked(virq, type, hwirq, fwspec)) return virq; - } - - pr_warn("type mismatch, failed to map hwirq-%lu for %s!\n", - hwirq, of_node_full_name(to_of_node(fwspec->fwnode))); return 0; }

@@ -839,8 +853,7 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) return virq; }

- irq_data = irq_get_irq_data(virq); - if (!irq_data) { + if (irq_set_trigger_type_locked(virq, type, hwirq, fwspec)) { if (irq_domain_is_hierarchy(domain)) irq_domain_free_irqs(virq, 1); else @@ -848,9 +861,6 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) return 0; }

- /* Store trigger type */ - irqd_set_trigger_type(irq_data, type); - return virq; } EXPORT_SYMBOL_GPL(irq_create_fwspec_mapping);