diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index 23b138e31e9c2fe229c42050ab2c5e864cac4710..504ad198e4ad0f999b43dfbb16f1957305e71ffe 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -886,7 +886,7 @@ asmlinkage void early_printk(const char *fmt, ...)
 	va_list ap;
 
 	va_start(ap, fmt);
-	n = vscnprintf(buf, 512, fmt, ap);
+	n = vscnprintf(buf, sizeof(buf), fmt, ap);
 	early_console->write(early_console, buf, n);
 	va_end(ap);
 }