diff --git a/winsup/cygwin/fhandler_proc.cc b/winsup/cygwin/fhandler_proc.cc
index f887e8cb7..86c3c81fb 100644
--- a/winsup/cygwin/fhandler_proc.cc
+++ b/winsup/cygwin/fhandler_proc.cc
@@ -327,7 +327,7 @@ fhandler_proc::fill_filebuf ()
 	    uname (&uts_name);
 		bufalloc = strlen (uts_name.sysname) + 1 + strlen (uts_name.release) +
 			  1 + strlen (uts_name.version) + 2;
-	    filebuf = (char *) realloc (filebuf, bufalloc);
+	    filebuf = (char *) cmalloc (HEAP_BUF, bufalloc);
 		filesize = __small_sprintf (filebuf, "%s %s %s\n", uts_name.sysname,
 			     uts_name.release, uts_name.version);
 	  }
@@ -335,13 +335,15 @@ fhandler_proc::fill_filebuf ()
       }
     case PROC_UPTIME:
       {
-	filebuf = (char *) realloc (filebuf, bufalloc = 80);
+	if (!filebuf)
+	  filebuf = (char *) cmalloc (HEAP_BUF, bufalloc = 80);
 	filesize = format_proc_uptime (filebuf, bufalloc);
 	break;
       }
     case PROC_STAT:
       {
-	filebuf = (char *) realloc (filebuf, bufalloc = 2048);
+	if (!filebuf)
+	  filebuf = (char *) cmalloc (HEAP_BUF, bufalloc = 2048);
 	filesize = format_proc_stat (filebuf, bufalloc);
 	break;
       }
@@ -352,14 +354,16 @@ fhandler_proc::fill_filebuf ()
 	 * Windows 95/98/me does have the KERNEL/CPUUsage performance counter
 	 * which is similar.
 	 */
-	filebuf = (char *) realloc (filebuf, bufalloc = 16);
+	if (!filebuf)
+	  filebuf = (char *) cmalloc (HEAP_BUF, bufalloc = 16);
 	filesize = __small_sprintf (filebuf, "%u.%02u %u.%02u %u.%02u\n",
 				    0, 0, 0, 0, 0, 0);
 	break;
       }
     case PROC_MEMINFO:
       {
-	filebuf = (char *) realloc (filebuf, bufalloc = 2048);
+	if (!filebuf)
+	  filebuf = (char *) cmalloc (HEAP_BUF, bufalloc = 2048);
 	filesize = format_proc_meminfo (filebuf, bufalloc);
 	break;
       }