of: unittest: fix null pointer dereferencing in of_unittest_find_node_by_name()

when kmalloc() fail to allocate memory in kasprintf(), name
or full_name will be NULL, strcmp() will cause
null pointer dereference.

Fixes: 0d638a07 ("of: Convert to using %pOF instead of full_name")
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Link: https://lore.kernel.org/r/20230727080246.519539-1-ruanjinjie@huawei.comSigned-off-by: Rob Herring <robh@kernel.org>

drivers/of/unittest.c

@@ -77,7 +77,7 @@ static void __init of_unittest_find_node_by_name(void)
 
 	np = of_find_node_by_path("/testcase-data");
 	name = kasprintf(GFP_KERNEL, "%pOF", np);
-	unittest(np && !strcmp("/testcase-data", name),
+	unittest(np && name && !strcmp("/testcase-data", name),
 		"find /testcase-data failed\n");
 	of_node_put(np);
 	kfree(name);
@@ -88,14 +88,14 @@ static void __init of_unittest_find_node_by_name(void)
 
 	np = of_find_node_by_path("/testcase-data/phandle-tests/consumer-a");
 	name = kasprintf(GFP_KERNEL, "%pOF", np);
-	unittest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", name),
+	unittest(np && name && !strcmp("/testcase-data/phandle-tests/consumer-a", name),
 		"find /testcase-data/phandle-tests/consumer-a failed\n");
 	of_node_put(np);
 	kfree(name);
 
 	np = of_find_node_by_path("testcase-alias");
 	name = kasprintf(GFP_KERNEL, "%pOF", np);
-	unittest(np && !strcmp("/testcase-data", name),
+	unittest(np && name && !strcmp("/testcase-data", name),
 		"find testcase-alias failed\n");
 	of_node_put(np);
 	kfree(name);
@@ -106,7 +106,7 @@ static void __init of_unittest_find_node_by_name(void)
 
 	np = of_find_node_by_path("testcase-alias/phandle-tests/consumer-a");
 	name = kasprintf(GFP_KERNEL, "%pOF", np);
-	unittest(np && !strcmp("/testcase-data/phandle-tests/consumer-a", name),
+	unittest(np && name && !strcmp("/testcase-data/phandle-tests/consumer-a", name),
 		"find testcase-alias/phandle-tests/consumer-a failed\n");
 	of_node_put(np);
 	kfree(name);
@@ -1533,6 +1533,8 @@ static void attach_node_and_children(struct device_node *np)
 	const char *full_name;
 
 	full_name = kasprintf(GFP_KERNEL, "%pOF", np);
+	if (!full_name)
+		return;
 
 	if (!strcmp(full_name, "/__local_fixups__") ||
 	    !strcmp(full_name, "/__fixups__")) {