[PATCH] powerpc/smp: Add check for kcalloc() in parse_thread_groups()

[Guangshuo Li]

As kcalloc() may fail, check its return value to avoid a NULL pointer
dereference when passing it to of_property_read_u32_array().

Fixes: 790a1662d3a26 ("powerpc/smp: Parse ibm,thread-groups with multiple properties")
Cc: stable at vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244 at gmail.com>
---
 arch/powerpc/kernel/smp.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index dac45694a9c9..34de27d75b1b 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -822,9 +822,9 @@ static int parse_thread_groups(struct device_node *dn,
 
 	count = of_property_count_u32_elems(dn, "ibm,thread-groups");
 	thread_group_array = kcalloc(count, sizeof(u32), GFP_KERNEL);
-	if (!thread_group_array) {
-	ret = -ENOMEM;
-	goto out_free;
+	if (!thread_group_array) {	/* check kcalloc() to avoid NULL deref */
+		ret = -ENOMEM;
+		goto out_free;
 	}
 	ret = of_property_read_u32_array(dn, "ibm,thread-groups",
 					 thread_group_array, count);
-- 
2.43.0