diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index e727fe0d145..4b6755984d2 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -58,12 +58,13 @@ struct bug_entry {
  */
 #ifndef __WARN
 #ifndef __ASSEMBLY__
-extern void warn_slowpath(const char *file, const int line,
+extern void warn_slowpath_fmt(const char *file, const int line,
 		const char *fmt, ...) __attribute__((format(printf, 3, 4)));
+extern void warn_slowpath_null(const char *file, const int line);
 #define WANT_WARN_ON_SLOWPATH
 #endif
-#define __WARN()		warn_slowpath(__FILE__, __LINE__, NULL)
-#define __WARN_printf(arg...)	warn_slowpath(__FILE__, __LINE__, arg)
+#define __WARN()		warn_slowpath_null(__FILE__, __LINE__)
+#define __WARN_printf(arg...)	warn_slowpath_fmt(__FILE__, __LINE__, arg)
 #else
 #define __WARN_printf(arg...)	do { printk(arg); __WARN(); } while (0)
 #endif
diff --git a/kernel/panic.c b/kernel/panic.c
index 3dcaa166135..874ecf1307a 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -340,7 +340,7 @@ void oops_exit(void)
 }
 
 #ifdef WANT_WARN_ON_SLOWPATH
-void warn_slowpath(const char *file, int line, const char *fmt, ...)
+void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
 {
 	va_list args;
 	char function[KSYM_SYMBOL_LEN];
@@ -356,7 +356,7 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
 	if (board)
 		printk(KERN_WARNING "Hardware name: %s\n", board);
 
-	if (fmt) {
+	if (*fmt) {
 		va_start(args, fmt);
 		vprintk(fmt, args);
 		va_end(args);
@@ -367,7 +367,14 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
 	print_oops_end_marker();
 	add_taint(TAINT_WARN);
 }
-EXPORT_SYMBOL(warn_slowpath);
+EXPORT_SYMBOL(warn_slowpath_fmt);
+
+void warn_slowpath_null(const char *file, int line)
+{
+	static const char *empty = "";
+	warn_slowpath_fmt(file, line, empty);
+}
+EXPORT_SYMBOL(warn_slowpath_null);
 #endif
 
 #ifdef CONFIG_CC_STACKPROTECTOR