diff --git a/gio/gdbusmessage.c b/gio/gdbusmessage.c
index 0b803bc30..cc8f37e5d 100644
--- a/gio/gdbusmessage.c
+++ b/gio/gdbusmessage.c
@@ -51,6 +51,7 @@
 #include "gseekable.h"
 #include "gioerror.h"
 #include "gdbusprivate.h"
+#include "gutilsprivate.h"
 
 #ifdef G_OS_UNIX
 #include "gunixfdlist.h"
@@ -257,17 +258,6 @@ g_memory_buffer_read_uint64 (GMemoryBuffer  *mbuf,
 
 #define MIN_ARRAY_SIZE  128
 
-static gsize
-g_nearest_pow (gsize num)
-{
-  gsize n = 1;
-
-  while (n < num && n > 0)
-    n <<= 1;
-
-  return n;
-}
-
 static void
 array_resize (GMemoryBuffer  *mbuf,
               gsize           size)
diff --git a/gio/gmemoryoutputstream.c b/gio/gmemoryoutputstream.c
index b120ccedc..6a410ebb5 100644
--- a/gio/gmemoryoutputstream.c
+++ b/gio/gmemoryoutputstream.c
@@ -29,6 +29,7 @@
 #include "gioerror.h"
 #include "string.h"
 #include "glibintl.h"
+#include "gutilsprivate.h"
 
 
 /**
@@ -596,17 +597,6 @@ array_resize (GMemoryOutputStream  *ostream,
   return TRUE;
 }
 
-static gsize
-g_nearest_pow (gsize num)
-{
-  gsize n = 1;
-
-  while (n < num && n > 0)
-    n <<= 1;
-
-  return n;
-}
-
 static gssize
 g_memory_output_stream_write (GOutputStream  *stream,
                               const void     *buffer,
diff --git a/glib/garray.c b/glib/garray.c
index 254921247..3803fee03 100644
--- a/glib/garray.c
+++ b/glib/garray.c
@@ -42,6 +42,7 @@
 #include "gmessages.h"
 #include "gqsort.h"
 #include "grefcount.h"
+#include "gutilsprivate.h"
 
 /**
  * SECTION:arrays
@@ -159,7 +160,6 @@ struct _GRealArray
     g_array_elt_zero ((array), (array)->len, 1);                        \
 }G_STMT_END
 
-static gsize g_nearest_pow        (gsize       num) G_GNUC_CONST;
 static void  g_array_maybe_expand (GRealArray *array,
                                    guint       len);
 
@@ -972,28 +972,6 @@ g_array_binary_search (GArray        *array,
   return result;
 }
 
-/* Returns the smallest power of 2 greater than or equal to n,
- * or 0 if such power does not fit in a gsize
- */
-static gsize
-g_nearest_pow (gsize num)
-{
-  gsize n = num - 1;
-
-  g_assert (num > 0 && num <= G_MAXSIZE / 2);
-
-  n |= n >> 1;
-  n |= n >> 2;
-  n |= n >> 4;
-  n |= n >> 8;
-  n |= n >> 16;
-#if GLIB_SIZEOF_SIZE_T == 8
-  n |= n >> 32;
-#endif
-
-  return n + 1;
-}
-
 static void
 g_array_maybe_expand (GRealArray *array,
                       guint       len)
@@ -1525,8 +1503,16 @@ static void
 g_ptr_array_maybe_expand (GRealPtrArray *array,
                           guint          len)
 {
+  guint max_len;
+
+  /* The maximum array length is derived from following constraints:
+   * - The number of bytes must fit into a gsize / 2.
+   * - The number of elements must fit into guint.
+   */
+  max_len = MIN (G_MAXSIZE / 2 / sizeof (gpointer), G_MAXUINT);
+
   /* Detect potential overflow */
-  if G_UNLIKELY ((G_MAXUINT - array->len) < len)
+  if G_UNLIKELY ((max_len - array->len) < len)
     g_error ("adding %u to array would overflow", len);
 
   if ((array->len + len) > array->alloc)
diff --git a/glib/gstring.c b/glib/gstring.c
index 17dc2c33d..0a509e5e5 100644
--- a/glib/gstring.c
+++ b/glib/gstring.c
@@ -37,6 +37,7 @@
 #include "gstring.h"
 #include "guriprivate.h"
 #include "gprintf.h"
+#include "gutilsprivate.h"
 
 
 /**
@@ -71,34 +72,21 @@
  * The GString struct contains the public fields of a GString.
  */
 
-
-#define MY_MAXSIZE ((gsize)-1)
-
-static inline gsize
-nearest_power (gsize base, gsize num)
-{
-  if (num > MY_MAXSIZE / 2)
-    {
-      return MY_MAXSIZE;
-    }
-  else
-    {
-      gsize n = base;
-
-      while (n < num)
-        n <<= 1;
-
-      return n;
-    }
-}
-
 static void
 g_string_maybe_expand (GString *string,
                        gsize    len)
 {
+  /* Detect potential overflow */
+  if G_UNLIKELY ((G_MAXSIZE - string->len - 1) < len)
+    g_error ("adding %" G_GSIZE_FORMAT " to string would overflow", len);
+
   if (string->len + len >= string->allocated_len)
     {
-      string->allocated_len = nearest_power (1, string->len + len + 1);
+      string->allocated_len = g_nearest_pow (string->len + len + 1);
+      /* If the new size is bigger than G_MAXSIZE / 2, only allocate enough
+       * memory for this string and don't over-allocate. */
+      if (string->allocated_len == 0)
+        string->allocated_len = string->len + len + 1;
       string->str = g_realloc (string->str, string->allocated_len);
     }
 }
diff --git a/glib/gstringchunk.c b/glib/gstringchunk.c
index 524eadcef..feacb154f 100644
--- a/glib/gstringchunk.c
+++ b/glib/gstringchunk.c
@@ -37,6 +37,7 @@
 #include "gmessages.h"
 
 #include "gutils.h"
+#include "gutilsprivate.h"
 
 /**
  * SECTION:string_chunks
@@ -82,27 +83,6 @@ struct _GStringChunk
   gsize       default_size;
 };
 
-#define MY_MAXSIZE ((gsize)-1)
-
-static inline gsize
-nearest_power (gsize base,
-               gsize num)
-{
-  if (num > MY_MAXSIZE / 2)
-    {
-      return MY_MAXSIZE;
-    }
-  else
-    {
-      gsize n = base;
-
-      while (n < num)
-        n <<= 1;
-
-      return n;
-    }
-}
-
 /**
  * g_string_chunk_new:
  * @size: the default size of the blocks of memory which are
@@ -120,7 +100,7 @@ g_string_chunk_new (gsize size)
   GStringChunk *new_chunk = g_new (GStringChunk, 1);
   gsize actual_size = 1;
 
-  actual_size = nearest_power (1, size);
+  actual_size = g_nearest_pow (MAX (1, size));
 
   new_chunk->const_table  = NULL;
   new_chunk->storage_list = NULL;
@@ -280,7 +260,7 @@ g_string_chunk_insert_len (GStringChunk *chunk,
                            const gchar  *string,
                            gssize        len)
 {
-  gssize size;
+  gsize size;
   gchar* pos;
 
   g_return_val_if_fail (chunk != NULL, NULL);
@@ -288,11 +268,16 @@ g_string_chunk_insert_len (GStringChunk *chunk,
   if (len < 0)
     size = strlen (string);
   else
-    size = len;
+    size = (gsize) len;
 
-  if ((chunk->storage_next + size + 1) > chunk->this_size)
+  if ((G_MAXSIZE - chunk->storage_next < size + 1) || (chunk->storage_next + size + 1) > chunk->this_size)
     {
-      gsize new_size = nearest_power (chunk->default_size, size + 1);
+      gsize new_size = g_nearest_pow (MAX (chunk->default_size, size + 1));
+
+      /* If size is bigger than G_MAXSIZE / 2 then store it in its own
+       * allocation instead of failing here */
+      if (new_size == 0)
+        new_size = size + 1;
 
       chunk->storage_list = g_slist_prepend (chunk->storage_list,
                                              g_new (gchar, new_size));
diff --git a/glib/gutilsprivate.h b/glib/gutilsprivate.h
index 5a0686086..a3996f8b7 100644
--- a/glib/gutilsprivate.h
+++ b/glib/gutilsprivate.h
@@ -20,7 +20,9 @@
 #ifndef __G_UTILS_PRIVATE_H__
 #define __G_UTILS_PRIVATE_H__
 
+#include "glibconfig.h"
 #include "gtypes.h"
+#include "gtestutils.h"
 
 G_BEGIN_DECLS
 
@@ -28,6 +30,28 @@ GLIB_AVAILABLE_IN_2_60
 void g_set_user_dirs (const gchar *first_dir_type,
                       ...) G_GNUC_NULL_TERMINATED;
 
+/* Returns the smallest power of 2 greater than or equal to n,
+ * or 0 if such power does not fit in a gsize
+ */
+static inline gsize
+g_nearest_pow (gsize num)
+{
+  gsize n = num - 1;
+
+  g_assert (num > 0 && num <= G_MAXSIZE / 2);
+
+  n |= n >> 1;
+  n |= n >> 2;
+  n |= n >> 4;
+  n |= n >> 8;
+  n |= n >> 16;
+#if GLIB_SIZEOF_SIZE_T == 8
+  n |= n >> 32;
+#endif
+
+  return n + 1;
+}
+
 G_END_DECLS
 
 #endif /* __G_UTILS_PRIVATE_H__ */