The following commit has been merged into the irq/irqchip-next branch of irqchip:

Commit-ID: 8932c32c3053accd50702b36e944ac2016cd103c Gitweb: https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/8932c32c30... Author: Marc Zyngier maz@kernel.org AuthorDate: Mon, 13 Feb 2023 11:42:49 +01:00 Committer: Marc Zyngier maz@kernel.org CommitterDate: Mon, 13 Feb 2023 19:31:24

irqdomain: Fix domain registration race

Hierarchical domains created using irq_domain_create_hierarchy() are currently added to the domain list before having been fully initialised.

This specifically means that a racing allocation request might fail to allocate irq data for the inner domains of a hierarchy in case the parent domain pointer has not yet been set up.

Note that this is not really any issue for irqchip drivers that are registered early (e.g. via IRQCHIP_DECLARE() or IRQCHIP_ACPI_DECLARE()) but could potentially cause trouble with drivers that are registered later (e.g. modular drivers using IRQCHIP_PLATFORM_DRIVER_BEGIN(), gpiochip drivers, etc.).

Fixes: afb7da83b9f4 ("irqdomain: Introduce helper function irq_domain_add_hierarchy()") Cc: stable@vger.kernel.org # 3.19 Signed-off-by: Marc Zyngier maz@kernel.org [ johan: add commit message ] Signed-off-by: Johan Hovold johan+linaro@kernel.org Signed-off-by: Marc Zyngier maz@kernel.org Link: https://lore.kernel.org/r/20230213104302.17307-8-johan+linaro@kernel.org --- kernel/irq/irqdomain.c | 62 ++++++++++++++++++++++++++++------------- 1 file changed, 43 insertions(+), 19 deletions(-)

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index df0cbad..a6d1b10 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -126,23 +126,12 @@ void irq_domain_free_fwnode(struct fwnode_handle *fwnode) } EXPORT_SYMBOL_GPL(irq_domain_free_fwnode);

-/** - * __irq_domain_add() - Allocate a new irq_domain data structure - * @fwnode: firmware node for the interrupt controller - * @size: Size of linear map; 0 for radix mapping only - * @hwirq_max: Maximum number of interrupts supported by controller - * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no - * direct mapping - * @ops: domain callbacks - * @host_data: Controller private data pointer - * - * Allocates and initializes an irq_domain structure. - * Returns pointer to IRQ domain, or NULL on failure. - */ -struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, unsigned int size, - irq_hw_number_t hwirq_max, int direct_max, - const struct irq_domain_ops *ops, - void *host_data) +static struct irq_domain *__irq_domain_create(struct fwnode_handle *fwnode, + unsigned int size, + irq_hw_number_t hwirq_max, + int direct_max, + const struct irq_domain_ops *ops, + void *host_data) { struct irqchip_fwid *fwid; struct irq_domain *domain; @@ -230,12 +219,44 @@ struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, unsigned int s

irq_domain_check_hierarchy(domain);

+ return domain; +} + +static void __irq_domain_publish(struct irq_domain *domain) +{ mutex_lock(&irq_domain_mutex); debugfs_add_domain_dir(domain); list_add(&domain->link, &irq_domain_list); mutex_unlock(&irq_domain_mutex);

pr_debug("Added domain %s\n", domain->name); +} + +/** + * __irq_domain_add() - Allocate a new irq_domain data structure + * @fwnode: firmware node for the interrupt controller + * @size: Size of linear map; 0 for radix mapping only + * @hwirq_max: Maximum number of interrupts supported by controller + * @direct_max: Maximum value of direct maps; Use ~0 for no limit; 0 for no + * direct mapping + * @ops: domain callbacks + * @host_data: Controller private data pointer + * + * Allocates and initializes an irq_domain structure. + * Returns pointer to IRQ domain, or NULL on failure. + */ +struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, unsigned int size, + irq_hw_number_t hwirq_max, int direct_max, + const struct irq_domain_ops *ops, + void *host_data) +{ + struct irq_domain *domain; + + domain = __irq_domain_create(fwnode, size, hwirq_max, direct_max, + ops, host_data); + if (domain) + __irq_domain_publish(domain); + return domain; } EXPORT_SYMBOL_GPL(__irq_domain_add); @@ -1138,12 +1159,15 @@ struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent, struct irq_domain *domain;

if (size) - domain = irq_domain_create_linear(fwnode, size, ops, host_data); + domain = __irq_domain_create(fwnode, size, size, 0, ops, host_data); else - domain = irq_domain_create_tree(fwnode, ops, host_data); + domain = __irq_domain_create(fwnode, 0, ~0, 0, ops, host_data); + if (domain) { domain->parent = parent; domain->flags |= flags; + + __irq_domain_publish(domain); }

return domain;