irqchip/irq-msi-lib: Check for NULL ops in msi_lib_irq_domain_select()

The irq_domain passed to msi_lib_irq_domain_select() may not have
msi_parent_ops set. There is a NULL pointer check for it, but unfortunately
there is a dereference of the parent ops pointer before that.

Move the NULL pointer test before the first use of that pointer.

This was found on a MacchiatoBin (Marvell Armada 8K SoC), which uses the
irq-mvebu-sei driver.

Fixes: 72e257c6f058 ("irqchip: Provide irq-msi-lib")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20240823100733.1900666-1-maxime.chevallier@bootlin.com
Closes: https://lore.kernel.org/all/20240821165034.1af97bad@fedora-3.home/

diff --git a/drivers/irqchip/irq-msi-lib.c b/drivers/irqchip/irq-msi-lib.c
index b5b90003311a1899477c4dabe86cb988e18462dd..d8e29fc0d4068b133a0da0de306c3d14ac5a3b50 100644 (file)
--- a/drivers/irqchip/irq-msi-lib.c
+++ b/drivers/irqchip/irq-msi-lib.c
@@ -128,6 +128,9 @@ 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);
 
+       if (!ops)
+               return 0;
+
        if (fwspec->fwnode != d->fwnode || fwspec->param_count != 0)
                return 0;
 
@@ -135,6 +138,6 @@ int msi_lib_irq_domain_select(struct irq_domain *d, struct irq_fwspec *fwspec,
        if (bus_token == ops->bus_select_token)
                return 1;
 
-       return ops && !!(ops->bus_select_mask & busmask);
+       return !!(ops->bus_select_mask & busmask);
 }
 EXPORT_SYMBOL_GPL(msi_lib_irq_domain_select);