1 files changed, 3 insertions, 0 deletions

diff --git a/lib/libc/stdio/snprintf.c b/lib/libc/stdio/snprintf.c
index e3e71f227bd3..e4cc7fcfea4e 100644
--- a/lib/libc/stdio/snprintf.c
+++ b/lib/libc/stdio/snprintf.c
@@ -53,6 +53,7 @@ snprintf(char *str, size_t n, char const *fmt, ...)
 	int ret;
 	va_list ap;
 	FILE f;
+	struct __sFILEX ext;
 
 	on = n;
 	if (n != 0)
@@ -64,6 +65,8 @@ snprintf(char *str, size_t n, char const *fmt, ...)
 	f._flags = __SWR | __SSTR;
 	f._bf._base = f._p = (unsigned char *)str;
 	f._bf._size = f._w = n;
+	f._extra = &ext;
+	INITEXTRA(&f);
 	ret = __vfprintf(&f, fmt, ap);
 	if (on > 0)
 		*f._p = '\0';