From 20c4d49c0f304f3f945bbd560b26afa98f75a0c4 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 25 Aug 2017 15:14:09 +0300 Subject: [PATCH] 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: 495c38d3001f ("irqdomain: Add irq_domain_{push,pop}_irq() functions") Signed-off-by: Dan Carpenter Signed-off-by: Thomas Gleixner Acked-by: David Daney Cc: Marc Zyngier Cc: kernel-janitors@vger.kernel.org Link: http://lkml.kernel.org/r/20170825121409.6rfv4vt6ztz2oqkt@mwanda --- kernel/irq/irqdomain.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c index 1ff9912211e9..d62351714f3e 100644 --- a/kernel/irq/irqdomain.c +++ b/kernel/irq/irqdomain.c @@ -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, -- 2.20.1