diff -pruN glibc-2.17-c758a686/csu/libc-start.c glibc-2.17-c758a686.new/csu/libc-start.c
--- glibc-2.17-c758a686/csu/libc-start.c	2012-12-25 08:32:13.000000000 +0530
+++ glibc-2.17-c758a686.new/csu/libc-start.c	2013-07-30 11:46:44.571901690 +0530
@@ -32,7 +32,7 @@ extern int __libc_multiple_libcs;
 #include <tls.h>
 #ifndef SHARED
 # include <dl-osinfo.h>
-extern void __pthread_initialize_minimal (void);
+extern void __pthread_initialize_minimal (int, char **, char **);
 # ifndef THREAD_SET_STACK_GUARD
 /* Only exported for architectures that don't store the stack guard canary
    in thread local area.  */
@@ -175,7 +175,7 @@ LIBC_START_MAIN (int (*main) (int, char
   /* Initialize the thread library at least a bit since the libgcc
      functions are using thread functions if these are available and
      we need to setup errno.  */
-  __pthread_initialize_minimal ();
+  __pthread_initialize_minimal (argc, argv, __environ);
 
   /* Set up the stack checker's canary.  */
   uintptr_t stack_chk_guard = _dl_setup_stack_chk_guard (_dl_random);
diff -pruN glibc-2.17-c758a686/csu/libc-tls.c glibc-2.17-c758a686.new/csu/libc-tls.c
--- glibc-2.17-c758a686/csu/libc-tls.c	2012-12-25 08:32:13.000000000 +0530
+++ glibc-2.17-c758a686.new/csu/libc-tls.c	2013-07-30 11:46:44.572901690 +0530
@@ -243,7 +243,7 @@ _dl_tls_setup (void)
    not used.  */
 void
 __attribute__ ((weak))
-__pthread_initialize_minimal (void)
+__pthread_initialize_minimal (int argc, char **argv, char **envp)
 {
   __libc_setup_tls (TLS_INIT_TCB_SIZE, TLS_INIT_TCB_ALIGN);
 }
diff -pruN glibc-2.17-c758a686/nptl/Makefile glibc-2.17-c758a686.new/nptl/Makefile
--- glibc-2.17-c758a686/nptl/Makefile	2013-07-30 11:46:34.909902026 +0530
+++ glibc-2.17-c758a686.new/nptl/Makefile	2013-07-30 11:46:44.573901690 +0530
@@ -201,7 +201,7 @@ CFLAGS-pt-system.c = -fexceptions
 
 
 tests = tst-typesizes \
-	tst-attr1 tst-attr2 tst-attr3 \
+	tst-attr1 tst-attr2 tst-attr3 tst-default-attr \
 	tst-mutex1 tst-mutex2 tst-mutex3 tst-mutex4 tst-mutex5 tst-mutex6 \
 	tst-mutex7 tst-mutex8 tst-mutex9 tst-mutex5a tst-mutex7a \
 	tst-mutexpi1 tst-mutexpi2 tst-mutexpi3 tst-mutexpi4 tst-mutexpi5 \
@@ -276,6 +276,13 @@ gen-as-const-headers = pthread-errnos.sy
 
 LDFLAGS-pthread.so = -Wl,--enable-new-dtags,-z,nodelete,-z,initfirst
 
+# The size is 1MB + 4KB.  The extra 4KB has been added to prevent allocatestack
+# from resizing the input size to avoid the 64K aliasing conflict on Intel
+# processors.
+DEFAULT_STACKSIZE=1052672
+CFLAGS-tst-default-attr.c = -DDEFAULT_STACKSIZE=$(DEFAULT_STACKSIZE)
+tst-default-attr-ENV = GLIBC_PTHREAD_STACKSIZE=$(DEFAULT_STACKSIZE)
+
 include ../Makeconfig
 
 ifeq ($(have-forced-unwind),yes)
diff -pruN glibc-2.17-c758a686/nptl/nptl-init.c glibc-2.17-c758a686.new/nptl/nptl-init.c
--- glibc-2.17-c758a686/nptl/nptl-init.c	2013-07-30 11:46:35.112902019 +0530
+++ glibc-2.17-c758a686.new/nptl/nptl-init.c	2013-07-30 11:46:44.601901689 +0530
@@ -35,6 +35,7 @@
 #include <smp.h>
 #include <lowlevellock.h>
 #include <kernel-features.h>
+#include <libc-internal.h>
 
 
 /* Size and alignment of static TLS block.  */
@@ -276,8 +277,28 @@ extern void **__libc_dl_error_tsd (void)
 /* This can be set by the debugger before initialization is complete.  */
 static bool __nptl_initial_report_events __attribute_used__;
 
+/* Validate and set the default stacksize.  */
+static void
+set_default_stacksize (size_t stacksize)
+{
+  if (stacksize < PTHREAD_STACK_MIN)
+    stacksize = PTHREAD_STACK_MIN;
+
+  /* Make sure it meets the minimum size that allocate_stack
+     (allocatestack.c) will demand, which depends on the page size.  */
+  const uintptr_t pagesz = GLRO(dl_pagesize);
+  const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
+
+  if (stacksize < minstack)
+    stacksize = minstack;
+
+  /* Round the resource limit up to page size.  */
+  stacksize = ALIGN_UP (stacksize, pagesz);
+  __default_pthread_attr.stacksize = stacksize;
+}
+
 void
-__pthread_initialize_minimal_internal (void)
+__pthread_initialize_minimal_internal (int argc, char **argv, char **envp)
 {
 #ifndef SHARED
   /* Unlike in the dynamically linked case the dynamic linker has not
@@ -401,29 +422,44 @@ __pthread_initialize_minimal_internal (v
 
   __static_tls_size = roundup (__static_tls_size, static_tls_align);
 
-  /* Determine the default allowed stack size.  This is the size used
-     in case the user does not specify one.  */
-  struct rlimit limit;
-  if (__getrlimit (RLIMIT_STACK, &limit) != 0
-      || limit.rlim_cur == RLIM_INFINITY)
-    /* The system limit is not usable.  Use an architecture-specific
-       default.  */
-    limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
-  else if (limit.rlim_cur < PTHREAD_STACK_MIN)
-    /* The system limit is unusably small.
-       Use the minimal size acceptable.  */
-    limit.rlim_cur = PTHREAD_STACK_MIN;
+  /* Initialize the environment.  libc.so gets initialized after us due to a
+     circular dependency and hence __environ is not available otherwise.  */
+  __environ = envp; 
 
-  /* Make sure it meets the minimum size that allocate_stack
-     (allocatestack.c) will demand, which depends on the page size.  */
-  const uintptr_t pagesz = GLRO(dl_pagesize);
-  const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
-  if (limit.rlim_cur < minstack)
-    limit.rlim_cur = minstack;
+#ifndef SHARED
+  __libc_init_secure ();
+#endif
 
-  /* Round the resource limit up to page size.  */
-  limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
-  __default_pthread_attr.stacksize = limit.rlim_cur;
+  /* Get the default stack size from the environment variable if it is set and
+     is valid.  */
+  size_t stacksize = 0;
+  char *envval = __libc_secure_getenv ("GLIBC_PTHREAD_STACKSIZE");
+
+  if (__builtin_expect (envval != NULL && envval[0] != '\0', 0))
+    {
+      char *env_conv = envval;
+      size_t ret = strtoul (envval, &env_conv, 0);
+
+      if (*env_conv == '\0' && env_conv != envval)
+	stacksize = ret;
+    }
+
+  if (stacksize == 0)
+    {
+      /* Determine the default allowed stack size.  */
+      struct rlimit limit;
+      if (__getrlimit (RLIMIT_STACK, &limit) != 0
+	  || limit.rlim_cur == RLIM_INFINITY)
+	/* The system limit is not usable.  Use an architecture-specific
+	   default.  */
+	stacksize = ARCH_STACK_DEFAULT_SIZE;
+      else
+	stacksize = limit.rlim_cur;
+    }
+
+  /* Finally, set the default stack size.  This size is used when the user does
+     not specify a stack size during thread creation.  */
+  set_default_stacksize (stacksize);
   __default_pthread_attr.guardsize = GLRO (dl_pagesize);
 
 #ifdef SHARED
diff -pruN glibc-2.17-c758a686/nptl/tst-default-attr.c glibc-2.17-c758a686.new/nptl/tst-default-attr.c
--- glibc-2.17-c758a686/nptl/tst-default-attr.c	1970-01-01 05:30:00.000000000 +0530
+++ glibc-2.17-c758a686.new/nptl/tst-default-attr.c	2013-07-30 11:46:44.601901689 +0530
@@ -0,0 +1,109 @@
+/* Verify that default stack size gets set correctly from the environment
+   variable.
+
+   Copyright (C) 2013 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <pthread.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+
+#define RETURN_IF_FAIL(f, ...) \
+  ({									      \
+    int ret = f (__VA_ARGS__);						      \
+    if (ret != 0)							      \
+      {									      \
+	printf ("%s:%d: %s returned %d (errno = %d)\n", __FILE__, __LINE__,   \
+		#f, ret, errno);					      \
+	return ret;							      \
+      }									      \
+  })
+
+/* DEFAULT_STACKSIZE macro is defined in the Makefile.  */
+static size_t stacksize = DEFAULT_STACKSIZE;
+
+static int
+verify_stacksize_result (pthread_attr_t *attr)
+{
+  size_t stack;
+
+  RETURN_IF_FAIL (pthread_attr_getstacksize, attr, &stack);
+
+  if (stacksize != stack)
+    {
+      printf ("failed to set default stacksize (%zu, %zu)\n", stacksize, stack);
+      return 1;
+    }
+
+  return 0;
+}
+
+static void *
+thr (void *unused __attribute__ ((unused)))
+{
+  pthread_attr_t attr;
+  int ret;
+
+  memset (&attr, 0xab, sizeof attr);
+  /* To verify that the attributes actually got applied.  */
+  if ((ret = pthread_getattr_np (pthread_self (), &attr)) != 0)
+    {
+      printf ("pthread_getattr_np failed: %s\n", strerror (ret));
+      goto out;
+    }
+
+  ret = verify_stacksize_result (&attr);
+
+out:
+  return (void *) (uintptr_t) ret;
+}
+
+static int
+run_threads (void)
+{
+  pthread_t t;
+  void *tret = NULL;
+
+  /* Run twice to ensure that the attributes do not get overwritten in the
+     first run somehow.  */
+  for (int i = 0; i < 2; i++)
+    {
+      RETURN_IF_FAIL (pthread_create, &t, NULL, thr, NULL);
+      RETURN_IF_FAIL (pthread_join, t, &tret);
+
+      if (tret != NULL)
+	{
+	  puts ("Thread failed");
+	  return 1;
+	}
+    }
+
+  return 0;
+}
+
+static int
+do_test (void)
+{
+  RETURN_IF_FAIL (run_threads);
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"