[PATCH v3] Loongarch: env: fix missing NULL checks for kstrdup

[Li Jun]

1.Replacing `of_find_node_by_path("/")` with `of_root` avoids multiple
calls to `of_node_put()`.
2.Fixes potential kernel oops during early boot when memory
allocation fails while parsing CPU model from device tree.

--Replacing `of_find_node_by_path("/")` with `of_root`,
Fix missing NULL checks.

Signed-off-by: Li Jun <lijun01@xxxxxxxxxx>
---
 arch/loongarch/kernel/env.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/kernel/env.c b/arch/loongarch/kernel/env.c
index 841206fde3ab..2afc9b09f139 100644
--- a/arch/loongarch/kernel/env.c
+++ b/arch/loongarch/kernel/env.c
@@ -15,6 +15,7 @@
 #include <asm/loongson.h>
 #include <asm/setup.h>
 #include <asm/time.h>
+#include <linux/of.h>
 
 u64 efi_system_table;
 struct loongson_system_configuration loongson_sysconf;
@@ -42,16 +43,15 @@ static int __init init_cpu_fullname(void)
 	int cpu, ret;
 	char *cpuname;
 	const char *model;
-	struct device_node *root;
 
 	/* Parsing cpuname from DTS model property */
-	root = of_find_node_by_path("/");
-	ret = of_property_read_string(root, "model", &model);
+	ret = of_property_read_string(of_root, "model", &model);
 	if (ret == 0) {
 		cpuname = kstrdup(model, GFP_KERNEL);
+		if (!cpuname)
+			return -ENOMEM;
 		loongson_sysconf.cpuname = strsep(&cpuname, " ");
 	}
-	of_node_put(root);
 
 	if (loongson_sysconf.cpuname && !strncmp(loongson_sysconf.cpuname, "Loongson", 8)) {
 		for (cpu = 0; cpu < NR_CPUS; cpu++)
-- 
2.34.1