1 files changed, 3 insertions, 1 deletions
diff --git a/sysemu.h b/sysemu.h
index d77de09c1c..aa036bfd1f 100644
--- a/sysemu.h
+++ b/sysemu.h
@@ -154,6 +154,8 @@ typedef enum {
     BLOCK_ERR_STOP_ANY
 } BlockInterfaceErrorAction;
 
+#define BLOCK_SERIAL_STRLEN 20
+
 typedef struct DriveInfo {
     BlockDriverState *bdrv;
     const char *devaddr;
@@ -163,7 +165,7 @@ typedef struct DriveInfo {
     int used;
     int drive_opt_idx;
     BlockInterfaceErrorAction onerror;
-    char serial[21];
+    char serial[BLOCK_SERIAL_STRLEN + 1];
 } DriveInfo;
 
 #define MAX_IDE_DEVS	2