From: Johan Hovold <johan+linaro@kernel.org>

Date: Mon, 13 Feb 2023 11:42:48 +0100

Subject: [PATCH] irqdomain: Fix mapping-creation race

References: bsc#1012628

Patch-mainline: 6.2.3

Git-commit: 601363cc08da25747feb87c55573dd54de91d66a

commit 601363cc08da25747feb87c55573dd54de91d66a upstream.

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

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 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 7b57949b..bfda4adc 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)

 {

 }

-- 

2.35.3