diff --git a/qemu-char.c b/qemu-char.c
index f6bdf2f..cbd6b9a 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -94,6 +94,7 @@
 CharDriverState *qemu_chr_alloc(void)
 {
     CharDriverState *chr = g_malloc0(sizeof(CharDriverState));
+    qemu_mutex_init(&chr->chr_write_lock);
     return chr;
 }