[PATCH stable-5.15 0/2] irqdomain: Fix mapping-creation race

[PATCH stable-5.15 0/2] irqdomain: Fix mapping-creation race

[Johan Hovold]

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

Here are backports of the irqdomain fixes that failed to apply to 5.15.

Johan

Johan Hovold (2):
  irqdomain: Refactor __irq_domain_alloc_irqs()
  irqdomain: Fix mapping-creation race

 kernel/irq/irqdomain.c | 152 +++++++++++++++++++++++++----------------
 1 file changed, 94 insertions(+), 58 deletions(-)

-- 
2.39.2

[PATCH stable-5.15 1/2] irqdomain: Refactor __irq_domain_alloc_irqs()

[Johan Hovold]

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

Refactor __irq_domain_alloc_irqs() so that it can be called internally
while holding the irq_domain_mutex.

This will be used to fix a shared-interrupt mapping race, hence the
Fixes tag.

Fixes: b62b2cf5759b ("irqdomain: Fix handling of type settings for existing mappings")
Cc: stable@vger.kernel.org      # 4.8
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/20230213104302.17307-6-johan+linaro@kernel.org
[ johan: backport to 5.15; adjust context ]
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 kernel/irq/irqdomain.c | 88 +++++++++++++++++++++++-------------------
 1 file changed, 48 insertions(+), 40 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index 298f9c12023c..f95196063884 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -1464,40 +1464,12 @@ int irq_domain_alloc_irqs_hierarchy(struct irq_domain *domain,
 	return domain->ops->alloc(domain, irq_base, nr_irqs, arg);
 }
 
-/**
- * __irq_domain_alloc_irqs - Allocate IRQs from domain
- * @domain:	domain to allocate from
- * @irq_base:	allocate specified IRQ number if irq_base >= 0
- * @nr_irqs:	number of IRQs to allocate
- * @node:	NUMA node id for memory allocation
- * @arg:	domain specific argument
- * @realloc:	IRQ descriptors have already been allocated if true
- * @affinity:	Optional irq affinity mask for multiqueue devices
- *
- * Allocate IRQ numbers and initialized all data structures to support
- * hierarchy IRQ domains.
- * Parameter @realloc is mainly to support legacy IRQs.
- * Returns error code or allocated IRQ number
- *
- * The whole process to setup an IRQ has been split into two steps.
- * The first step, __irq_domain_alloc_irqs(), is to allocate IRQ
- * descriptor and required hardware resources. The second step,
- * irq_domain_activate_irq(), is to program the hardware with preallocated
- * resources. In this way, it's easier to rollback when failing to
- * allocate resources.
- */
-int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
-			    unsigned int nr_irqs, int node, void *arg,
-			    bool realloc, const struct irq_affinity_desc *affinity)
+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)
 {
 	int i, ret, virq;
 
-	if (domain == NULL) {
-		domain = irq_default_domain;
-		if (WARN(!domain, "domain is NULL; cannot allocate IRQ\n"))
-			return -EINVAL;
-	}
-
 	if (realloc && irq_base >= 0) {
 		virq = irq_base;
 	} else {
@@ -1516,24 +1488,18 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 		goto out_free_desc;
 	}
 
-	mutex_lock(&irq_domain_mutex);
 	ret = irq_domain_alloc_irqs_hierarchy(domain, virq, nr_irqs, arg);
-	if (ret < 0) {
-		mutex_unlock(&irq_domain_mutex);
+	if (ret < 0)
 		goto out_free_irq_data;
-	}
 
 	for (i = 0; i < nr_irqs; i++) {
 		ret = irq_domain_trim_hierarchy(virq + i);
-		if (ret) {
-			mutex_unlock(&irq_domain_mutex);
+		if (ret)
 			goto out_free_irq_data;
-		}
 	}
-	
+
 	for (i = 0; i < nr_irqs; i++)
 		irq_domain_insert_irq(virq + i);
-	mutex_unlock(&irq_domain_mutex);
 
 	return virq;
 
@@ -1544,6 +1510,48 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
 	return ret;
 }
 
+/**
+ * __irq_domain_alloc_irqs - Allocate IRQs from domain
+ * @domain:	domain to allocate from
+ * @irq_base:	allocate specified IRQ number if irq_base >= 0
+ * @nr_irqs:	number of IRQs to allocate
+ * @node:	NUMA node id for memory allocation
+ * @arg:	domain specific argument
+ * @realloc:	IRQ descriptors have already been allocated if true
+ * @affinity:	Optional irq affinity mask for multiqueue devices
+ *
+ * Allocate IRQ numbers and initialized all data structures to support
+ * hierarchy IRQ domains.
+ * Parameter @realloc is mainly to support legacy IRQs.
+ * Returns error code or allocated IRQ number
+ *
+ * The whole process to setup an IRQ has been split into two steps.
+ * The first step, __irq_domain_alloc_irqs(), is to allocate IRQ
+ * descriptor and required hardware resources. The second step,
+ * irq_domain_activate_irq(), is to program the hardware with preallocated
+ * resources. In this way, it's easier to rollback when failing to
+ * allocate resources.
+ */
+int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
+			    unsigned int nr_irqs, int node, void *arg,
+			    bool realloc, const struct irq_affinity_desc *affinity)
+{
+	int ret;
+
+	if (domain == NULL) {
+		domain = irq_default_domain;
+		if (WARN(!domain, "domain is NULL; cannot allocate IRQ\n"))
+			return -EINVAL;
+	}
+
+	mutex_lock(&irq_domain_mutex);
+	ret = irq_domain_alloc_irqs_locked(domain, irq_base, nr_irqs, node, arg,
+					   realloc, affinity);
+	mutex_unlock(&irq_domain_mutex);
+
+	return ret;
+}
+
 /* The irq_data was moved, fix the revmap to refer to the new location */
 static void irq_domain_fix_revmap(struct irq_data *d)
 {
-- 
2.39.2

[PATCH stable-5.15 2/2] irqdomain: Fix mapping-creation race

[Johan Hovold]

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

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: 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 f95196063884..e0b67784ac1e 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 {
@@ -703,9 +706,9 @@ 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;
@@ -720,7 +723,7 @@ 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;
 	}
@@ -756,14 +759,20 @@ 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);
 
@@ -830,6 +839,8 @@ 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.
@@ -842,7 +853,7 @@ 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
@@ -850,35 +861,45 @@ 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;
 }
@@ -1910,6 +1931,13 @@ 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)
 {
 }
-- 
2.39.2