user/netstack: ARP cache

1 files changed, 1 insertions, 0 deletions

diff --git a/src/shared/printf.c b/src/shared/printf.c
index 2dc3048..ff07c72 100644
--- a/src/shared/printf.c
+++ b/src/shared/printf.c
@@ -171,6 +171,7 @@ int __printf_internal(const char *fmt, va_list argp,
 static void vsnprintf_backend(void *arg, const char *buf, size_t len) {
 	char **ptrs = arg;
 	size_t space = ptrs[1] - ptrs[0];
+	if (!ptrs[0]) return;
 	if (len > space) len = space;
 
 	memcpy(ptrs[0], buf, len);