Commit 02cbf8e0 authored by Lorenzo Pieralisi's avatar Lorenzo Pieralisi Committed by Thomas Gleixner
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irqchip/msi-lib: Fix fwnode refcount in msi_lib_irq_domain_select() 



Commit 8b65db1e ("irqchip/msi-lib: Add IRQ_DOMAIN_FLAG_FWNODE_PARENT
handling") added logic in msi_lib_irq_domain_select() to match the domain
fwnode against the fwnode parent of the fwspec.fwnode.

The fwnode_get_parent() caller must call fwnode_handle_put() on the
returned pointer value, lest fwnode refcounting for the parent ends up
being out of kilter.

Fix this by relying on the fwnode_handle clean-up handlers and by
incrementing the fwnode refcount regardless of whether parent matching is
used or not (the domain selection code already holds a reference before
calling msi_lib_irq_domain_select() but to make the exit path more uniform
if IRQ_DOMAIN_FLAG_FWNODE_PARENT is not set fwnode_handle_get() is called
again on fwspec.fwnode so that the clean-up code is the same for the two
matching patterns).

Fixes: 8b65db1e ("irqchip/msi-lib: Add IRQ_DOMAIN_FLAG_FWNODE_PARENT handling")
Signed-off-by: default avatarLorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250804145553.795065-1-lpieralisi@kernel.org
parent cb9f6a40

drivers/irqchip/irq-msi-lib.c

+3 −3
Original line number Diff line number Diff line
@@ -133,13 +133,13 @@ int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec, 
{

	const struct msi_parent_ops *ops = d->msi_parent_ops;

	u32 busmask = BIT(bus_token);

	struct fwnode_handle *fwh;



	if (!ops)

		return 0;



	fwh = d->flags & IRQ_DOMAIN_FLAG_FWNODE_PARENT ? fwnode_get_parent(fwspec->fwnode)

						       : fwspec->fwnode;

	struct fwnode_handle *fwh __free(fwnode_handle) =

		d->flags & IRQ_DOMAIN_FLAG_FWNODE_PARENT ? fwnode_get_parent(fwspec->fwnode)

							 : fwnode_handle_get(fwspec->fwnode);

	if (fwh != d->fwnode || fwspec->param_count != 0)

		return 0;