Commit 20c4d49c authored Aug 25, 2017 by Dan Carpenter Committed by Thomas Gleixner Aug 25, 2017

irqdomain: Prevent potential NULL pointer dereference in irq_domain_push_irq()



This code generates a Smatch warning:

  kernel/irq/irqdomain.c:1511 irq_domain_push_irq()
  warn: variable dereferenced before check 'root_irq_data' (see line 1508)

irq_get_irq_data() can return a NULL pointer, but the code dereferences
the returned pointer before checking it.

Move the NULL pointer check before the dereference.

[ tglx: Rewrote changelog to be precise and conforming to the instructions
  	in submitting-patches and added a Fixes tag. Sigh! ]

Fixes: 495c38d3 ("irqdomain: Add irq_domain_{push,pop}_irq() functions")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Daney <david.daney@cavium.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: kernel-janitors@vger.kernel.org
Link: http://lkml.kernel.org/r/20170825121409.6rfv4vt6ztz2oqkt@mwanda

parent ce8bdd69

kernel/irq/irqdomain.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1504,10 +1504,10 @@ int irq_domain_push_irq(struct irq_domain domain, int virq, void arg)
		if (WARN_ON(!irq_domain_is_hierarchy(domain)))
		return -EINVAL;

		if (domain->parent != root_irq_data->domain)
		if (!root_irq_data)
		return -EINVAL;

		if (!root_irq_data)
		if (domain->parent != root_irq_data->domain)
		return -EINVAL;

		child_irq_data = kzalloc_node(sizeof(*child_irq_data), GFP_KERNEL,

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