--- old/src/jdk.hotspot.agent/linux/native/libsaproc/ps_proc.c	2017-05-25 14:37:18.472517922 +0530
+++ new/src/jdk.hotspot.agent/linux/native/libsaproc/ps_proc.c	2017-05-25 14:37:18.224641913 +0530
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -22,8 +22,6 @@
  *
  */
 
-#ifdef INCLUDE_SA_ATTACH
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -34,6 +32,9 @@
 #include <sys/wait.h>
 #include <sys/ptrace.h>
 #include <sys/uio.h>
+#ifndef INCLUDE_SA_ATTACH
+#include <dirent.h>
+#endif
 #include "libproc_impl.h"
 
 #if defined(x86_64) && !defined(amd64)
@@ -220,9 +221,11 @@
 static bool ptrace_attach(pid_t pid, char* err_buf, size_t err_buf_len) {
   if (ptrace(PTRACE_ATTACH, pid, NULL, NULL) < 0) {
     char buf[200];
-    char* msg = strerror_r(errno, buf, sizeof(buf));
-    snprintf(err_buf, err_buf_len, "ptrace(PTRACE_ATTACH, ..) failed for %d: %s", pid, msg);
-    print_debug("%s\n", err_buf);
+    if (strerror_r(errno, buf, sizeof(buf) == 0)) {
+      snprintf(err_buf, err_buf_len,
+               "ptrace(PTRACE_ATTACH, ..) failed for %d: %s", pid, buf);
+      print_debug("%s\n", err_buf);
+    }
     return false;
   } else {
     return ptrace_waitpid(pid);
@@ -401,6 +404,7 @@
   // the list of threads within the same process.
   read_lib_info(ph);
 
+#ifdef INCLUDE_SA_ATTACH
   // read thread info
   read_thread_info(ph, add_new_thread);
 
@@ -408,14 +412,47 @@
   thr = ph->threads;
   while (thr) {
      // don't attach to the main thread again
-    if (ph->pid != thr->lwp_id && ptrace_attach(thr->lwp_id, err_buf, err_buf_len) != true) {
+    if (pid != thr->lwp_id && ptrace_attach(thr->lwp_id, err_buf, err_buf_len) != true) {
         // even if one attach fails, we get return NULL
         Prelease(ph);
         return NULL;
      }
      thr = thr->next;
   }
+#else
+  DIR *dir = NULL;
+  struct dirent *ent = NULL;
+  char taskpath[80];
+
+  // Find the lwpids to attach to by traversing the /proc/<pid>/task/ directory,
+  // and attach to those.
+  snprintf (taskpath, sizeof (taskpath), "/proc/%ld/task", (unsigned long) pid);
+  if ((dir = opendir(taskpath)) != NULL) {
+    while ((ent = readdir (dir)) != NULL) {
+      unsigned long lwp;
+
+      if ((lwp = strtoul (ent->d_name, NULL, 10)) != 0) {
+        add_new_thread (ph, 0, lwp);
+
+        // Don't attach to the main thread again
+        if (lwp == (unsigned long) pid) {
+          continue;
+        }
+
+        if (ptrace_attach(lwp, err_buf, err_buf_len) != true) {
+          Prelease(ph);
+          closedir (dir);
+          return NULL;
+        }
+      }
+    }
+  } else {
+    print_debug("Could not open /proc/%ld/task.\n", (unsigned long) pid);
+    Prelease(ph);
+    return NULL;
+  }
+
+  closedir (dir);
+#endif
   return ph;
 }
-
-#endif // INCLUDE_SA_ATTACH