Parallel probing of devices that share interrupts (e.g. when a driver uses asynchronous probing) can currently result in two mappings for the same hardware interrupt to be created due to missing serialisation.

Make sure to hold the irq_domain_mutex when creating mappings so that looking for an existing mapping before creating a new one is done atomically.

Fixes: 765230b5f084 ("driver-core: add asynchronous probing support for drivers") Fixes: b62b2cf5759b ("irqdomain: Fix handling of type settings for existing mappings") Link: https://lore.kernel.org/r/YuJXMHoT4ijUxnRb@hovoldconsulting.com Cc: stable@vger.kernel.org # 4.8 Cc: Dmitry Torokhov dtor@chromium.org Cc: Jon Hunter jonathanh@nvidia.com Tested-by: Hsin-Yi Wang hsinyi@chromium.org Tested-by: Mark-PK Tsai mark-pk.tsai@mediatek.com Signed-off-by: Johan Hovold johan+linaro@kernel.org --- kernel/irq/irqdomain.c | 64 ++++++++++++++++++++++++++++++------------ 1 file changed, 46 insertions(+), 18 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 7b57949bc79c..bfda4adc05c0 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -25,6 +25,9 @@ static DEFINE_MUTEX(irq_domain_mutex);

static struct irq_domain *irq_default_domain;

+static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base, + unsigned int nr_irqs, int node, void *arg, + bool realloc, const struct irq_affinity_desc *affinity); static void irq_domain_check_hierarchy(struct irq_domain *domain);

struct irqchip_fwid { @@ -682,9 +685,9 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain) EXPORT_SYMBOL_GPL(irq_create_direct_mapping); #endif

-static unsigned int __irq_create_mapping_affinity(struct irq_domain *domain, - irq_hw_number_t hwirq, - const struct irq_affinity_desc *affinity) +static unsigned int irq_create_mapping_affinity_locked(struct irq_domain *domain, + irq_hw_number_t hwirq, + const struct irq_affinity_desc *affinity) { struct device_node *of_node = irq_domain_get_of_node(domain); int virq; @@ -699,7 +702,7 @@ static unsigned int __irq_create_mapping_affinity(struct irq_domain *domain, return 0; }

- if (irq_domain_associate(domain, virq, hwirq)) { + if (irq_domain_associate_locked(domain, virq, hwirq)) { irq_free_desc(virq); return 0; } @@ -735,14 +738,20 @@ unsigned int irq_create_mapping_affinity(struct irq_domain *domain, return 0; }

+ mutex_lock(&irq_domain_mutex); + /* Check if mapping already exists */ virq = irq_find_mapping(domain, hwirq); if (virq) { pr_debug("existing mapping on virq %d\n", virq); - return virq; + goto out; }

- return __irq_create_mapping_affinity(domain, hwirq, affinity); + virq = irq_create_mapping_affinity_locked(domain, hwirq, affinity); +out: + mutex_unlock(&irq_domain_mutex); + + return virq; } EXPORT_SYMBOL_GPL(irq_create_mapping_affinity);

@@ -809,6 +818,8 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) if (WARN_ON(type & ~IRQ_TYPE_SENSE_MASK)) type &= IRQ_TYPE_SENSE_MASK;

+ mutex_lock(&irq_domain_mutex); + /* * If we've already configured this interrupt, * don't do it again, or hell will break loose. @@ -821,7 +832,7 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) * interrupt number. */ if (type == IRQ_TYPE_NONE || type == irq_get_trigger_type(virq)) - return virq; + goto out;

/* * If the trigger type has not been set yet, then set @@ -829,35 +840,45 @@ unsigned int irq_create_fwspec_mapping(struct irq_fwspec *fwspec) */ if (irq_get_trigger_type(virq) == IRQ_TYPE_NONE) { irq_data = irq_get_irq_data(virq); - if (!irq_data) - return 0; + if (!irq_data) { + virq = 0; + goto out; + }

irqd_set_trigger_type(irq_data, type); - return virq; + goto out; }

pr_warn("type mismatch, failed to map hwirq-%lu for %s!\n", hwirq, of_node_full_name(to_of_node(fwspec->fwnode))); - return 0; + virq = 0; + goto out; }

if (irq_domain_is_hierarchy(domain)) { - virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, fwspec); - if (virq <= 0) - return 0; + virq = irq_domain_alloc_irqs_locked(domain, -1, 1, NUMA_NO_NODE, + fwspec, false, NULL); + if (virq <= 0) { + virq = 0; + goto out; + } } else { /* Create mapping */ - virq = __irq_create_mapping_affinity(domain, hwirq, NULL); + virq = irq_create_mapping_affinity_locked(domain, hwirq, NULL); if (!virq) - return virq; + goto out; }

irq_data = irq_get_irq_data(virq); - if (WARN_ON(!irq_data)) - return 0; + if (WARN_ON(!irq_data)) { + virq = 0; + goto out; + }

/* Store trigger type */ irqd_set_trigger_type(irq_data, type); +out: + mutex_unlock(&irq_domain_mutex);

return virq; } @@ -1888,6 +1909,13 @@ void irq_domain_set_info(struct irq_domain *domain, unsigned int virq, irq_set_handler_data(virq, handler_data); }

+static int irq_domain_alloc_irqs_locked(struct irq_domain *domain, int irq_base, + unsigned int nr_irqs, int node, void *arg, + bool realloc, const struct irq_affinity_desc *affinity) +{ + return -EINVAL; +} + static void irq_domain_check_hierarchy(struct irq_domain *domain) { }