diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index f21d6544c1c..1c3d7016510 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2017-02-13  Nick Clifton  <nickc@redhat.com>
+
+	PR binutils/21151
+	* dwarf2.c (_bfd_dwarf2_find_nearest_line): Check for an invalid
+	unit length field.
+
 2017-02-07  Andrew Waterman  <andrew@sifive.com>
 
 	* elfnn-riscv.c (riscv_elf_finish_dynamic_sections): Only write PLT
diff --git a/bfd/dwarf2.c b/bfd/dwarf2.c
index 369958765ad..6b111d3d7a0 100644
--- a/bfd/dwarf2.c
+++ b/bfd/dwarf2.c
@@ -4294,6 +4294,10 @@ _bfd_dwarf2_find_nearest_line (bfd *abfd,
 	{
 	  bfd_byte * new_ptr;
 
+	  /* PR 21151  */
+	  if (stash->info_ptr + length > stash->info_ptr_end)
+	    return FALSE;
+
 	  each = parse_comp_unit (stash, length, info_ptr_unit,
 				  offset_size);
 	  if (!each)