diff --git a/kernel/core_hook.c b/kernel/core_hook.c
index 8641a8ed..c6ac7d66 100644
--- a/kernel/core_hook.c
+++ b/kernel/core_hook.c
@@ -232,7 +232,7 @@ int ksu_handle_prctl(int option, unsigned long arg2, unsigned long arg3,
 		// someone wants to be root manager, just check it!
 		// arg3 should be `/data/user/<userId>/<manager_package_name>`
 		char param[128];
-		if (ksu_strncpy_from_user_nofault(param, arg3, sizeof(param))) {
+		if (ksu_strncpy_from_user_nofault(param, arg3, sizeof(param)) == -EFAULT) {
 #ifdef CONFIG_KSU_DEBUG
 			pr_err("become_manager: copy param err\n");
 #endif
diff --git a/kernel/kernel_compat.h b/kernel/kernel_compat.h
index 8e1df0ad..f47f43a5 100644
--- a/kernel/kernel_compat.h
+++ b/kernel/kernel_compat.h
@@ -11,7 +11,7 @@
 #elif LINUX_VERSION_CODE >= KERNEL_VERSION(5, 3, 0)
 #define ksu_strncpy_from_user_nofault strncpy_from_unsafe_user
 #else
-#define ksu_strncpy_from_user_nofault strncpy_from_user
+#define ksu_strncpy_from_user_nofault probe_kernel_read
 #endif
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(4, 10, 0)