irqdomain: Fix mapping-creation race

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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230213104302.17307-7-johan+linaro@kernel.org

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 78fb480..df0cbad 100644 (file)
--- 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)
 {
 }