On Thu, 09 Feb 2023 13:23:10 +0000,
Johan Hovold <johan+linaro@xxxxxxxxxx> wrote:
>
> 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@xxxxxxxxxxxxxxxxxxxx
> Cc: stable@xxxxxxxxxxxxxxx # 4.8
> Cc: Dmitry Torokhov <dtor@xxxxxxxxxxxx>
> Cc: Jon Hunter <jonathanh@xxxxxxxxxx>
> Tested-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> Tested-by: Mark-PK Tsai <mark-pk.tsai@xxxxxxxxxxxx>
> Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
> ---
> kernel/irq/irqdomain.c | 55 ++++++++++++++++++++++++++++++------------
> 1 file changed, 40 insertions(+), 15 deletions(-)
>
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index 7b57949bc79c..1ddb01bd49a4 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
> @@ -830,36 +841,43 @@ 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;
> + goto err;
>
> 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;
> + goto err;
> }
>
> if (irq_domain_is_hierarchy(domain)) {
> - virq = irq_domain_alloc_irqs(domain, 1, NUMA_NO_NODE, fwspec);
> + virq = irq_domain_alloc_irqs_locked(domain, -1, 1, NUMA_NO_NODE,
> + fwspec, false, NULL);
> if (virq <= 0)
> - return 0;
> + goto err;
> } 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 err;
> }
>
> irq_data = irq_get_irq_data(virq);
> if (WARN_ON(!irq_data))
> - return 0;
> + goto err;
>
> /* Store trigger type */
> irqd_set_trigger_type(irq_data, type);
> +out:
> + mutex_unlock(&irq_domain_mutex);
>
> return virq;
> +err:
> + mutex_unlock(&irq_domain_mutex);
> +
> + return 0;
nit: it'd look better if we had a single exit path with the unlock,
setting virq to 0 on failure. Not a big deal, as this can be tidied up
when applied.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
