diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 4c05e849da..bdfccbac78 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,7 @@
+2020-03-25  Alan Modra  <amodra@gmail.com>
+
+	* z80-dis.c (suffix): Init mybuf.
+
 2020-03-22  Alan Modra  <amodra@gmail.com>
 
 	* h8300-dis.c (bfd_h8_disassemble): Limit data[] access to that
diff --git a/opcodes/z80-dis.c b/opcodes/z80-dis.c
index b23e8e99fd..cd84044451 100644
--- a/opcodes/z80-dis.c
+++ b/opcodes/z80-dis.c
@@ -804,6 +804,7 @@ suffix (struct buffer *buf, disassemble_info *info, const char *txt)
   old_stream = info->stream;
   info->fprintf_func = (fprintf_ftype) &sprintf;
   info->stream = mybuf;
+  mybuf[0] = 0;
   buf->base++;
   if (print_insn_z80_buf (buf, info) >= 0)
     buf->n_used++;