diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 397a08f20b5..22a473a4037 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2019-06-17  Tom de Vries  <tdevries@suse.de>
+
+	PR gdb/24617
+	* common/pathstuff.c (child_path): Make sure parent_len > 0 before
+	accessing parent[parent_len - 1].
+
 2019-06-17  Paul Pluzhnikov  <ppluzhnikov@google.com>
 
 	PR gdb/24364
diff --git a/gdb/common/pathstuff.c b/gdb/common/pathstuff.c
index e0e048d6654..b295e73237b 100644
--- a/gdb/common/pathstuff.c
+++ b/gdb/common/pathstuff.c
@@ -158,7 +158,7 @@ child_path (const char *parent, const char *child)
   /* The parent path must be a directory and the child must contain at
      least one component underneath the parent.  */
   const char *child_component;
-  if (IS_DIR_SEPARATOR (parent[parent_len - 1]))
+  if (parent_len > 0 && IS_DIR_SEPARATOR (parent[parent_len - 1]))
     {
       /* The parent path ends in a directory separator, so it is a
 	 directory.  The first child component starts after the common