add patch series

5 files changed, 1126 insertions, 0 deletions

diff --git a/debian/patches/0001-libports-use-protected-payloads-to-optimize-the-obje.patch b/debian/patches/0001-libports-use-protected-payloads-to-optimize-the-obje.patch
new file mode 100644
index 00000000..c5575573
--- /dev/null
+++ b/debian/patches/0001-libports-use-protected-payloads-to-optimize-the-obje.patch
@@ -0,0 +1,364 @@
+From baa1d1e45d73ca0e5a402bae6e183ab22a176824 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 23 Nov 2013 16:12:55 +0100
+Subject: [PATCH hurd 1/4] libports: use protected payloads to optimize the
+ object lookup
+
+* libports/create-internal.c (_ports_create_port_internal): Set the
+protected payload to the objects address.
+* libports/import-port.c (ports_import_port): Likewise.
+* libports/reallocate-from-external.c (ports_reallocate_from_external):
+Likewise.
+* libports/reallocate-port.c (ports_reallocate_port): Likewise.
+* libports/transfer-right.c (ports_transfer_right): Likewise.
+* libports/manage-multithread.c (ports_manage_port_operations_multithread):
+Use the protected payload as the objects address if provided.
+* libports/manage-one-thread.c (ports_manage_port_operations_one_thread):
+Likewise.
+* libports/destroy-right.c (ports_destroy_right): Defer the
+dereferencing of outstanding send rights to avoid a port_info
+use-after-free if a no-senders notification is dispatched.
+(struct deferred_dereference, gc_loop, start_gc, defer_dereferencing):
+Simple generational garbage collection of outstanding send rights.
+---
+ libports/complete-deallocate.c      |   2 +-
+ libports/create-internal.c          |   6 +-
+ libports/destroy-right.c            | 133 ++++++++++++++++++++++++++++++++++--
+ libports/import-port.c              |   6 +-
+ libports/manage-multithread.c       |  22 +++++-
+ libports/manage-one-thread.c        |  22 +++++-
+ libports/reallocate-from-external.c |   4 ++
+ libports/reallocate-port.c          |   4 ++
+ libports/transfer-right.c           |   3 +
+ 9 files changed, 193 insertions(+), 9 deletions(-)
+
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 0d852f5..6799dfd 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -27,7 +27,7 @@ _ports_complete_deallocate (struct port_info *pi)
+ {
+   assert ((pi->flags & PORT_HAS_SENDRIGHTS) == 0);
+ 
+-  if (pi->port_right)
++  if (MACH_PORT_VALID (pi->port_right))
+     {
+       struct references result;
+ 
+diff --git a/libports/create-internal.c b/libports/create-internal.c
+index 2d85931..d79dc78 100644
+--- a/libports/create-internal.c
++++ b/libports/create-internal.c
+@@ -99,7 +99,11 @@ _ports_create_port_internal (struct port_class *class,
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+-  
++
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), port,
++				   (unsigned long) pi);
++
+   if (install)
+     {
+       err = mach_port_move_member (mach_task_self (), pi->port_right,
+diff --git a/libports/destroy-right.c b/libports/destroy-right.c
+index 448b379..c229d77 100644
+--- a/libports/destroy-right.c
++++ b/libports/destroy-right.c
+@@ -1,5 +1,5 @@
+ /*
+-   Copyright (C) 1995, 1996, 1999 Free Software Foundation, Inc.
++   Copyright (C) 1995, 1996, 1999, 2014 Free Software Foundation, Inc.
+    Written by Michael I. Bushnell.
+ 
+    This file is part of the GNU Hurd.
+@@ -22,30 +22,155 @@
+ #include <hurd/ihash.h>
+ #include <assert.h>
+ 
++#include <pthread.h>
++#include <error.h>
++#include <time.h>
++#include <unistd.h>
++
++/* To prevent protected payloads from becoming stale, we defer the
++   derefercing of port_info objects.  Consumes PI.  */
++static error_t defer_dereferencing (struct port_info *pi);
++
+ error_t
+ ports_destroy_right (void *portstruct)
+ {
+   struct port_info *pi = portstruct;
+   error_t err;
+ 
++  mach_port_clear_protected_payload (mach_task_self (),
++				     pi->port_right);
++
++  pthread_mutex_lock (&_ports_lock);
+   if (pi->port_right != MACH_PORT_NULL)
+     {
+       pthread_rwlock_wrlock (&_ports_htable_lock);
+       hurd_ihash_locp_remove (&_ports_htable, pi->ports_htable_entry);
+       hurd_ihash_locp_remove (&pi->bucket->htable, pi->hentry);
+       pthread_rwlock_unlock (&_ports_htable_lock);
++
+       err = mach_port_mod_refs (mach_task_self (), pi->port_right,
+ 				MACH_PORT_RIGHT_RECEIVE, -1);
+       assert_perror (err);
+ 
+-      pi->port_right = MACH_PORT_NULL;
+-
+       if (pi->flags & PORT_HAS_SENDRIGHTS)
+ 	{
+ 	  pi->flags &= ~PORT_HAS_SENDRIGHTS;
+-	  ports_port_deref (pi);
++
++	  /* There are outstanding send rights, so we might get a
++	     no-senders notification.  Attached to the notification
++	     is a reference to the port_info object.  Of course we
++	     destroyed the receive right these were send to above, but
++	     the message could already have been send and dequeued.
++
++	     Previously, those messages would have carried an stale
++	     name, which would have caused a hash table lookup
++	     failure.  However, stale payloads results in port_info
++	     use-after-free.  Therefore, we cannot release the
++	     reference here, but defer that instead.  */
++	  defer_dereferencing (pi);
+ 	}
++
++      pi->port_right = MACH_PORT_DEAD;
+     }
++  pthread_mutex_unlock (&_ports_lock);
++
++  return 0;
++}
++
++/* Simple lock-less generational garbage collection.  */
++
++/* We maintain three lists of objects.	Producers add objects to the
++   current generation G using defer_dereferencing.  G-1 holds old
++   objects, G-2 holds garbage.	*/
++static struct deferred_dereference
++{
++  struct deferred_dereference *next;
++  struct port_info *pi;	/* We hold a reference for these objects.  */
++} *generations[3];	/* Must be accessed using atomic
++			   operations.	*/
++
++/* The current generation.  Must be accessed using atomic operations.  */
++static int generation;
++
++/* The garbage collection thread.  Does not return.  */
++static void *
++gc_loop (void *arg)
++{
++  while (1)
++    {
++      int old, garbage;
++      struct deferred_dereference *d;
++
++      sleep (5);
++
++      /* We are the only one updating generation, so this is safe.  */
++      old = generation;
++
++      /* Update generation.  */
++      __atomic_store_n (&generation, (old + 1) % 3, __ATOMIC_RELAXED);
++
++      /* This is the garbage generation.  As all writers are long
++	 gone, we do not need to bother with atomic operations.	 */
++      garbage = (old + 2) % 3;
++      d = generations[garbage];
++      generations[garbage] = NULL;
++      while (d != NULL)
++	{
++	  struct deferred_dereference *next = d->next;
++
++	  /* Get rid of our reference.	*/
++	  ports_port_deref (d->pi);
++
++	  free (d);
++	  d = next;
++	}
++    }
++
++  assert (! "reached");
++  return NULL;
++}
++
++/* Start the gc thread.  */
++static void
++start_gc (void)
++{
++  error_t err;
++  pthread_attr_t attr;
++  pthread_t thread;
++
++  pthread_attr_init (&attr);
++#define STACK_SIZE (64 * 1024)
++  pthread_attr_setstacksize (&attr, STACK_SIZE);
++#undef STACK_SIZE
++
++  err = pthread_create (&thread, &attr, gc_loop, NULL);
++  assert_perror (err);
++  err = pthread_detach (thread);
++  assert_perror (err);
++}
++
++/* Defer the derefercing of port_info objects.  Consumes PI.  */
++static error_t
++defer_dereferencing (struct port_info *pi)
++{
++  static pthread_once_t once = PTHREAD_ONCE_INIT;
++  int g;
++  struct deferred_dereference *d;
++  pthread_once (&once, start_gc);
++
++  d = malloc (sizeof *d);
++  if (d == NULL)
++    return ENOMEM;
++  d->pi = pi;
++
++ retry:
++  /* Append to the current generation.	*/
++  g = __atomic_load_n (&generation, __ATOMIC_RELAXED);
++
++  d->next = __atomic_load_n (&generations[g], __ATOMIC_RELAXED);
++  if (! __atomic_compare_exchange_n (&generations[g], &d->next, d,
++				     0, __ATOMIC_RELAXED, __ATOMIC_RELAXED))
++    goto retry;
+ 
+   return 0;
+ }
+diff --git a/libports/import-port.c b/libports/import-port.c
+index c337c85..2c638e1 100644
+--- a/libports/import-port.c
++++ b/libports/import-port.c
+@@ -93,7 +93,11 @@ ports_import_port (struct port_class *class, struct port_bucket *bucket,
+   bucket->count++;
+   class->count++;
+   pthread_mutex_unlock (&_ports_lock);
+-  
++
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), port,
++				   (unsigned long) pi);
++
+   mach_port_move_member (mach_task_self (), port, bucket->portset);
+ 
+   if (stat.mps_srights)
+diff --git a/libports/manage-multithread.c b/libports/manage-multithread.c
+index 58814d2..9a5278e 100644
+--- a/libports/manage-multithread.c
++++ b/libports/manage-multithread.c
+@@ -167,7 +167,27 @@ ports_manage_port_operations_multithread (struct port_bucket *bucket,
+       outp->RetCodeType = RetCodeType;
+       outp->RetCode = MIG_BAD_ID;
+ 
+-      pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++      if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) ==
++	  MACH_MSG_TYPE_PROTECTED_PAYLOAD)
++	{
++	  pi = (struct port_info *) inp->msgh_protected_payload;
++	  if (pi && pi->bucket == bucket)
++	    ports_port_ref (pi);
++	  else
++	    pi = NULL;
++	}
++      else
++	{
++	  pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++	  if (pi)
++	    {
++	      inp->msgh_bits = MACH_MSGH_BITS (
++		MACH_MSGH_BITS_REMOTE (inp->msgh_bits),
++		MACH_MSG_TYPE_PROTECTED_PAYLOAD);
++	      inp->msgh_protected_payload = (unsigned long) pi;
++	    }
++	}
++
+       if (pi)
+ 	{
+ 	  error_t err = ports_begin_rpc (pi, inp->msgh_id, &link);
+diff --git a/libports/manage-one-thread.c b/libports/manage-one-thread.c
+index cbd2df7..58c0f36 100644
+--- a/libports/manage-one-thread.c
++++ b/libports/manage-one-thread.c
+@@ -57,7 +57,27 @@ ports_manage_port_operations_one_thread (struct port_bucket *bucket,
+       outp->RetCodeType = RetCodeType;
+       outp->RetCode = MIG_BAD_ID;
+ 
+-      pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++      if (MACH_MSGH_BITS_LOCAL (inp->msgh_bits) ==
++	  MACH_MSG_TYPE_PROTECTED_PAYLOAD)
++	{
++	  pi = (struct port_info *) inp->msgh_protected_payload;
++	  if (pi && pi->bucket == bucket)
++	    ports_port_ref (pi);
++	  else
++	    pi = NULL;
++	}
++      else
++	{
++	  pi = ports_lookup_port (bucket, inp->msgh_local_port, 0);
++	  if (pi)
++	    {
++	      inp->msgh_bits = MACH_MSGH_BITS (
++		MACH_MSGH_BITS_REMOTE (inp->msgh_bits),
++		MACH_MSG_TYPE_PROTECTED_PAYLOAD);
++	      inp->msgh_protected_payload = (unsigned long) pi;
++	    }
++	}
++
+       if (pi)
+ 	{
+ 	  err = ports_begin_rpc (pi, inp->msgh_id, &link);
+diff --git a/libports/reallocate-from-external.c b/libports/reallocate-from-external.c
+index 7205bd9..d0fae1a 100644
+--- a/libports/reallocate-from-external.c
++++ b/libports/reallocate-from-external.c
+@@ -71,6 +71,10 @@ ports_reallocate_from_external (void *portstruct, mach_port_t receive)
+   pthread_mutex_unlock (&_ports_lock);
+   assert_perror (err);
+ 
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), pi->port_right,
++				   (unsigned long) pi);
++
+   mach_port_move_member (mach_task_self (), receive, pi->bucket->portset);
+   
+   if (stat.mps_srights)
+diff --git a/libports/reallocate-port.c b/libports/reallocate-port.c
+index cc534eb..4e859a1 100644
+--- a/libports/reallocate-port.c
++++ b/libports/reallocate-port.c
+@@ -59,6 +59,10 @@ ports_reallocate_port (void *portstruct)
+   pthread_mutex_unlock (&_ports_lock);
+   assert_perror (err);
+ 
++  /* This is an optimization.  It may fail.  */
++  mach_port_set_protected_payload (mach_task_self (), pi->port_right,
++				   (unsigned long) pi);
++
+   err = mach_port_move_member (mach_task_self (), pi->port_right, 
+ 			       pi->bucket->portset);
+   assert_perror (err);
+diff --git a/libports/transfer-right.c b/libports/transfer-right.c
+index 776a8d2..64de7f7 100644
+--- a/libports/transfer-right.c
++++ b/libports/transfer-right.c
+@@ -91,6 +91,9 @@ ports_transfer_right (void *tostruct,
+       err = hurd_ihash_add (&topi->bucket->htable, port, topi);
+       pthread_rwlock_unlock (&_ports_htable_lock);
+       assert_perror (err);
++      /* This is an optimization.  It may fail.  */
++      mach_port_set_protected_payload (mach_task_self (), port,
++				       (unsigned long) topi);
+       if (topi->bucket != frompi->bucket)
+         {
+ 	  err = mach_port_move_member (mach_task_self (), port,
+-- 
+2.1.4
+
diff --git a/debian/patches/0002-xxx-fix-and-assert-reached.patch b/debian/patches/0002-xxx-fix-and-assert-reached.patch
new file mode 100644
index 00000000..b89b0d3a
--- /dev/null
+++ b/debian/patches/0002-xxx-fix-and-assert-reached.patch
@@ -0,0 +1,26 @@
+From bfa67266242b4457cfa108f72c9f000381518c26 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Fri, 3 Apr 2015 23:03:01 +0200
+Subject: [PATCH hurd 2/4] xxx fix, and assert !reached
+
+---
+ libports/complete-deallocate.c | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/libports/complete-deallocate.c b/libports/complete-deallocate.c
+index 6799dfd..c81425e 100644
+--- a/libports/complete-deallocate.c
++++ b/libports/complete-deallocate.c
+@@ -37,7 +37,8 @@ _ports_complete_deallocate (struct port_info *pi)
+         {
+           /* A reference was reacquired through a hash table lookup.
+              It's fine, we didn't touch anything yet. */
+-          pthread_mutex_unlock (&_ports_htable_lock);
++          assert (! "reacquired reference w/o send rights");
++          pthread_rwlock_unlock (&_ports_htable_lock);
+           return;
+         }
+ 
+-- 
+2.1.4
+
diff --git a/debian/patches/0003-new-design.patch b/debian/patches/0003-new-design.patch
new file mode 100644
index 00000000..2fde1825
--- /dev/null
+++ b/debian/patches/0003-new-design.patch
@@ -0,0 +1,452 @@
+From c9dce531c41baa55bdfd2cae22f2a029c7039f73 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 4 Apr 2015 13:22:30 +0200
+Subject: [PATCH hurd 3/4] new design
+
+---
+ libports/Makefile              |   2 +-
+ libports/create-bucket.c       |   1 +
+ libports/destroy-right.c       | 104 +--------------------------------
+ libports/manage-multithread.c  |  15 ++++-
+ libports/manage-one-thread.c   |   4 ++
+ libports/port-deref-deferred.c | 129 +++++++++++++++++++++++++++++++++++++++++
+ libports/port-deref-deferred.h |  32 ++++++++++
+ libports/ports.h               |   7 +++
+ 8 files changed, 189 insertions(+), 105 deletions(-)
+ create mode 100644 libports/port-deref-deferred.c
+ create mode 100644 libports/port-deref-deferred.h
+
+diff --git a/libports/Makefile b/libports/Makefile
+index f49cb9f..b8b82ee 100644
+--- a/libports/Makefile
++++ b/libports/Makefile
+@@ -36,7 +36,7 @@ SRCS = create-bucket.c create-class.c \
+  interrupt-operation.c interrupt-on-notify.c interrupt-notified-rpcs.c \
+  dead-name.c create-port.c import-port.c default-uninhibitable-rpcs.c \
+  claim-right.c transfer-right.c create-port-noinstall.c create-internal.c \
+- interrupted.c extern-inline.c
++ interrupted.c extern-inline.c port-deref-deferred.c
+ 
+ installhdrs = ports.h
+ 
+diff --git a/libports/create-bucket.c b/libports/create-bucket.c
+index 2c5f1b6..32b2b76 100644
+--- a/libports/create-bucket.c
++++ b/libports/create-bucket.c
+@@ -48,5 +48,6 @@ ports_create_bucket ()
+ 
+   hurd_ihash_init (&ret->htable, offsetof (struct port_info, hentry));
+   ret->rpcs = ret->flags = ret->count = 0;
++  _ports_sync_init (&ret->sync);
+   return ret;
+ }
+diff --git a/libports/destroy-right.c b/libports/destroy-right.c
+index c229d77..a9a9702 100644
+--- a/libports/destroy-right.c
++++ b/libports/destroy-right.c
+@@ -27,10 +27,6 @@
+ #include <time.h>
+ #include <unistd.h>
+ 
+-/* To prevent protected payloads from becoming stale, we defer the
+-   derefercing of port_info objects.  Consumes PI.  */
+-static error_t defer_dereferencing (struct port_info *pi);
+-
+ error_t
+ ports_destroy_right (void *portstruct)
+ {
+@@ -67,7 +63,7 @@ ports_destroy_right (void *portstruct)
+ 	     failure.  However, stale payloads results in port_info
+ 	     use-after-free.  Therefore, we cannot release the
+ 	     reference here, but defer that instead.  */
+-	  defer_dereferencing (pi);
++	  _ports_port_deref_deferred (pi);
+ 	}
+ 
+       pi->port_right = MACH_PORT_DEAD;
+@@ -76,101 +72,3 @@ ports_destroy_right (void *portstruct)
+ 
+   return 0;
+ }
+-
+-/* Simple lock-less generational garbage collection.  */
+-
+-/* We maintain three lists of objects.	Producers add objects to the
+-   current generation G using defer_dereferencing.  G-1 holds old
+-   objects, G-2 holds garbage.	*/
+-static struct deferred_dereference
+-{
+-  struct deferred_dereference *next;
+-  struct port_info *pi;	/* We hold a reference for these objects.  */
+-} *generations[3];	/* Must be accessed using atomic
+-			   operations.	*/
+-
+-/* The current generation.  Must be accessed using atomic operations.  */
+-static int generation;
+-
+-/* The garbage collection thread.  Does not return.  */
+-static void *
+-gc_loop (void *arg)
+-{
+-  while (1)
+-    {
+-      int old, garbage;
+-      struct deferred_dereference *d;
+-
+-      sleep (5);
+-
+-      /* We are the only one updating generation, so this is safe.  */
+-      old = generation;
+-
+-      /* Update generation.  */
+-      __atomic_store_n (&generation, (old + 1) % 3, __ATOMIC_RELAXED);
+-
+-      /* This is the garbage generation.  As all writers are long
+-	 gone, we do not need to bother with atomic operations.	 */
+-      garbage = (old + 2) % 3;
+-      d = generations[garbage];
+-      generations[garbage] = NULL;
+-      while (d != NULL)
+-	{
+-	  struct deferred_dereference *next = d->next;
+-
+-	  /* Get rid of our reference.	*/
+-	  ports_port_deref (d->pi);
+-
+-	  free (d);
+-	  d = next;
+-	}
+-    }
+-
+-  assert (! "reached");
+-  return NULL;
+-}
+-
+-/* Start the gc thread.  */
+-static void
+-start_gc (void)
+-{
+-  error_t err;
+-  pthread_attr_t attr;
+-  pthread_t thread;
+-
+-  pthread_attr_init (&attr);
+-#define STACK_SIZE (64 * 1024)
+-  pthread_attr_setstacksize (&attr, STACK_SIZE);
+-#undef STACK_SIZE
+-
+-  err = pthread_create (&thread, &attr, gc_loop, NULL);
+-  assert_perror (err);
+-  err = pthread_detach (thread);
+-  assert_perror (err);
+-}
+-
+-/* Defer the derefercing of port_info objects.  Consumes PI.  */
+-static error_t
+-defer_dereferencing (struct port_info *pi)
+-{
+-  static pthread_once_t once = PTHREAD_ONCE_INIT;
+-  int g;
+-  struct deferred_dereference *d;
+-  pthread_once (&once, start_gc);
+-
+-  d = malloc (sizeof *d);
+-  if (d == NULL)
+-    return ENOMEM;
+-  d->pi = pi;
+-
+- retry:
+-  /* Append to the current generation.	*/
+-  g = __atomic_load_n (&generation, __ATOMIC_RELAXED);
+-
+-  d->next = __atomic_load_n (&generations[g], __ATOMIC_RELAXED);
+-  if (! __atomic_compare_exchange_n (&generations[g], &d->next, d,
+-				     0, __ATOMIC_RELAXED, __ATOMIC_RELAXED))
+-    goto retry;
+-
+-  return 0;
+-}
+diff --git a/libports/manage-multithread.c b/libports/manage-multithread.c
+index 9a5278e..a5952e8 100644
+--- a/libports/manage-multithread.c
++++ b/libports/manage-multithread.c
+@@ -223,10 +223,19 @@ ports_manage_port_operations_multithread (struct port_bucket *bucket,
+   void *
+   thread_function (void *arg)
+     {
++      struct ports_thread thread;
+       int master = (int) arg;
+       int timeout;
+       error_t err;
+ 
++      int synchronized_demuxer (mach_msg_header_t *inp,
++				mach_msg_header_t *outheadp)
++      {
++	int r = internal_demuxer (inp, outheadp);
++	_ports_thread_quiescent (bucket, &thread);
++	return r;
++      }
++
+       adjust_priority (__atomic_load_n (&totalthreads, __ATOMIC_RELAXED));
+ 
+       if (hook)
+@@ -237,10 +246,13 @@ ports_manage_port_operations_multithread (struct port_bucket *bucket,
+       else
+ 	timeout = thread_timeout;
+ 
++      _ports_thread_online (bucket, &thread);
++
+     startover:
+ 
+       do
+-	err = mach_msg_server_timeout (internal_demuxer, 0, bucket->portset,
++	err = mach_msg_server_timeout (synchronized_demuxer,
++				       0, bucket->portset,
+ 				       timeout ? MACH_RCV_TIMEOUT : 0,
+ 				       timeout);
+       while (err != MACH_RCV_TIMED_OUT);
+@@ -260,6 +272,7 @@ ports_manage_port_operations_multithread (struct port_bucket *bucket,
+ 	    }
+ 	  __atomic_sub_fetch (&totalthreads, 1, __ATOMIC_RELAXED);
+ 	}
++      _ports_thread_offline (bucket, &thread);
+       return NULL;
+     }
+ 
+diff --git a/libports/manage-one-thread.c b/libports/manage-one-thread.c
+index 58c0f36..0a8e4e7 100644
+--- a/libports/manage-one-thread.c
++++ b/libports/manage-one-thread.c
+@@ -25,6 +25,7 @@ ports_manage_port_operations_one_thread (struct port_bucket *bucket,
+ 					 ports_demuxer_type demuxer,
+ 					 int timeout)
+ {
++  struct ports_thread thread;
+   error_t err;
+ 
+   int 
+@@ -103,6 +104,7 @@ ports_manage_port_operations_one_thread (struct port_bucket *bucket,
+ 	  status = 1;
+ 	}
+ 
++      _ports_thread_quiescent (bucket, &thread);
+       return status;
+     }
+ 
+@@ -113,8 +115,10 @@ ports_manage_port_operations_one_thread (struct port_bucket *bucket,
+      zero.  */
+   timeout = 0;
+ 
++  _ports_thread_online (bucket, &thread);
+   do
+     err = mach_msg_server_timeout (internal_demuxer, 0, bucket->portset, 
+ 				   timeout ? MACH_RCV_TIMEOUT : 0, timeout);
+   while (err != MACH_RCV_TIMED_OUT);
++  _ports_thread_offline (bucket, &thread);
+ }
+diff --git a/libports/port-deref-deferred.c b/libports/port-deref-deferred.c
+new file mode 100644
+index 0000000..27604c5
+--- /dev/null
++++ b/libports/port-deref-deferred.c
+@@ -0,0 +1,129 @@
++#include "ports.h"
++#include <assert.h>
++
++#include <pthread.h>
++
++#define COLOR_VALID(X) ((X) == COLOR_BLACK || (X) == COLOR_WHITE)
++
++void
++_ports_sync_init (struct ports_sync *s)
++{
++  pthread_spin_init (&s->lock, PTHREAD_PROCESS_PRIVATE);
++  s->color = COLOR_BLACK;
++  s->old_threads = 0;
++  s->old_objects = NULL;
++  s->young_threads = 0;
++  s->young_objects = NULL;
++}
++
++static inline enum def_color
++flip_color (enum def_color c)
++{
++  switch (c)
++    {
++    case COLOR_BLACK:
++      return COLOR_WHITE;
++    case COLOR_WHITE:
++      return COLOR_BLACK;
++    default:
++      assert (! "invalid color");
++    }
++}
++
++static inline void
++flip_generations (struct ports_sync *s)
++{
++  assert (s->old_threads == 0);
++  s->old_threads = s->young_threads;
++  s->old_objects = s->young_objects;
++  s->young_threads = 0;
++  s->young_objects = NULL;
++  s->color = flip_color (s->color);
++}
++
++void
++_ports_port_deref_deferred (struct port_info *pi)
++{
++  struct ports_sync *s = &pi->bucket->sync;
++
++  struct pi_list *pl = malloc (sizeof *pl);
++  if (pl == NULL)
++    return;
++  pl->pi = pi;
++
++  pthread_spin_lock (&s->lock);
++  pl->next = s->young_objects;
++  s->young_objects = pl;
++  if (s->old_threads == 0)
++    {
++      assert (s->old_objects == NULL);
++      flip_generations (s);
++    }
++  pthread_spin_unlock (&s->lock);
++}
++
++void
++_ports_thread_online (struct port_bucket *bucket,
++		      struct ports_thread *t)
++{
++  struct ports_sync *s = &bucket->sync;
++  pthread_spin_lock (&s->lock);
++  t->color = flip_color (s->color);
++  s->young_threads += 1;
++  pthread_spin_unlock (&s->lock);
++}
++
++void
++_ports_thread_quiescent (struct port_bucket *bucket,
++			 struct ports_thread *t)
++{
++  struct ports_sync *s = &bucket->sync;
++  struct pi_list *free_list = NULL, *p;
++  assert (COLOR_VALID (t->color));
++
++  pthread_spin_lock (&s->lock);
++  if (t->color == s->color)
++    {
++      s->old_threads -= 1;
++      s->young_threads += 1;
++      t->color = flip_color (t->color);
++
++      if (s->old_threads == 0)
++	{
++	  free_list = s->old_objects;
++	  flip_generations (s);
++	}
++    }
++  pthread_spin_unlock (&s->lock);
++
++  if (free_list)
++    error (0, 0, "dereferencing %p, my color is %d", free_list, t->color);
++
++  for (p = free_list; p;)
++    {
++      struct pi_list *old = p;
++      p = p->next;
++
++      ports_port_deref (old->pi);
++      free (old);
++    }
++}
++
++void
++_ports_thread_offline (struct port_bucket *bucket,
++		       struct ports_thread *t)
++{
++  struct ports_sync *s = &bucket->sync;
++  assert (COLOR_VALID (t->color));
++ retry:
++  pthread_spin_lock (&s->lock);
++  if (t->color == s->color)
++    {
++      pthread_spin_unlock (&s->lock);
++      _ports_thread_quiescent (bucket, t);
++      goto retry;
++    }
++  t->color = COLOR_NONE;
++  s->young_threads -= 1;
++  pthread_spin_unlock (&s->lock);
++}
+diff --git a/libports/port-deref-deferred.h b/libports/port-deref-deferred.h
+new file mode 100644
+index 0000000..6586c81
+--- /dev/null
++++ b/libports/port-deref-deferred.h
+@@ -0,0 +1,32 @@
++#ifndef	_HURD_PORTS_DEREF_DEFERRED_
++#define	_HURD_PORTS_DEREF_DEFERRED_
++
++enum def_color { COLOR_NONE, COLOR_BLACK, COLOR_WHITE };
++
++struct pi_list
++{
++  struct pi_list *next;
++  struct port_info *pi;
++};
++
++struct ports_sync
++{
++  pthread_spinlock_t lock;
++
++  enum def_color color;
++
++  size_t old_threads;
++  struct pi_list *old_objects;
++
++  size_t young_threads;
++  struct pi_list *young_objects;
++};
++
++struct ports_thread
++{
++  enum def_color color;
++};
++
++void _ports_sync_init (struct ports_sync *s);
++
++#endif	/* _HURD_PORTS_DEREF_DEFERRED_ */
+diff --git a/libports/ports.h b/libports/ports.h
+index f02edb4..c047a1a 100644
+--- a/libports/ports.h
++++ b/libports/ports.h
+@@ -29,6 +29,8 @@
+ #include <pthread.h>
+ #include <refcount.h>
+ 
++#include "port-deref-deferred.h"
++
+ #ifdef PORTS_DEFINE_EI
+ #define PORTS_EI
+ #else
+@@ -73,6 +75,7 @@ struct port_bucket
+   int rpcs;
+   int flags;
+   int count;
++  struct ports_sync sync;
+ };
+ /* FLAGS above are the following: */
+ #define PORT_BUCKET_INHIBITED	PORTS_INHIBITED
+@@ -477,4 +480,8 @@ void _ports_complete_deallocate (struct port_info *);
+ error_t _ports_create_port_internal (struct port_class *, struct port_bucket *,
+ 				     size_t, void *, int);
+ 
++void _ports_thread_online (struct port_bucket *, struct ports_thread *);
++void _ports_thread_quiescent (struct port_bucket *, struct ports_thread *);
++void _ports_thread_offline (struct port_bucket *, struct ports_thread *);
++
+ #endif
+-- 
+2.1.4
+
diff --git a/debian/patches/0004-renamed-stuff.patch b/debian/patches/0004-renamed-stuff.patch
new file mode 100644
index 00000000..e74633ed
--- /dev/null
+++ b/debian/patches/0004-renamed-stuff.patch
@@ -0,0 +1,280 @@
+From f18e34a4a6cd93bad8af6e720f52c71b020c3f69 Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sat, 4 Apr 2015 13:57:30 +0200
+Subject: [PATCH hurd 4/4] renamed stuff
+
+---
+ libports/create-bucket.c       |   2 +-
+ libports/port-deref-deferred.c | 139 ++++++++++++++++++++++-------------------
+ libports/port-deref-deferred.h |  16 ++---
+ libports/ports.h               |   2 +-
+ 4 files changed, 82 insertions(+), 77 deletions(-)
+
+diff --git a/libports/create-bucket.c b/libports/create-bucket.c
+index 32b2b76..82c00a4 100644
+--- a/libports/create-bucket.c
++++ b/libports/create-bucket.c
+@@ -48,6 +48,6 @@ ports_create_bucket ()
+ 
+   hurd_ihash_init (&ret->htable, offsetof (struct port_info, hentry));
+   ret->rpcs = ret->flags = ret->count = 0;
+-  _ports_sync_init (&ret->sync);
++  _ports_threadpool_init (&ret->threadpool);
+   return ret;
+ }
+diff --git a/libports/port-deref-deferred.c b/libports/port-deref-deferred.c
+index 27604c5..06b57f8 100644
+--- a/libports/port-deref-deferred.c
++++ b/libports/port-deref-deferred.c
+@@ -3,101 +3,112 @@
+ 
+ #include <pthread.h>
+ 
+-#define COLOR_VALID(X) ((X) == COLOR_BLACK || (X) == COLOR_WHITE)
++/*
++ * A threadpool has a color indicating which threads belong to the old
++ * generation.
++ */
++#define COLOR_BLACK	0
++#define COLOR_WHITE	1
++#define COLOR_INVALID	~0U
++
++static inline int
++valid_color (unsigned int c)
++{
++  return c == COLOR_BLACK || c == COLOR_WHITE;
++}
+ 
+-void
+-_ports_sync_init (struct ports_sync *s)
++static inline unsigned int
++flip_color (unsigned int c)
+ {
+-  pthread_spin_init (&s->lock, PTHREAD_PROCESS_PRIVATE);
+-  s->color = COLOR_BLACK;
+-  s->old_threads = 0;
+-  s->old_objects = NULL;
+-  s->young_threads = 0;
+-  s->young_objects = NULL;
++  assert (valid_color (c));
++  return ! c;
+ }
+ 
+-static inline enum def_color
+-flip_color (enum def_color c)
++void
++_ports_threadpool_init (struct ports_threadpool *pool)
+ {
+-  switch (c)
+-    {
+-    case COLOR_BLACK:
+-      return COLOR_WHITE;
+-    case COLOR_WHITE:
+-      return COLOR_BLACK;
+-    default:
+-      assert (! "invalid color");
+-    }
++  pthread_spin_init (&pool->lock, PTHREAD_PROCESS_PRIVATE);
++  pool->color = COLOR_BLACK;
++  pool->old_threads = 0;
++  pool->old_objects = NULL;
++  pool->young_threads = 0;
++  pool->young_objects = NULL;
+ }
+ 
+ static inline void
+-flip_generations (struct ports_sync *s)
++flip_generations (struct ports_threadpool *pool)
+ {
+-  assert (s->old_threads == 0);
+-  s->old_threads = s->young_threads;
+-  s->old_objects = s->young_objects;
+-  s->young_threads = 0;
+-  s->young_objects = NULL;
+-  s->color = flip_color (s->color);
++  assert (pool->old_threads == 0);
++  pool->old_threads = pool->young_threads;
++  pool->old_objects = pool->young_objects;
++  pool->young_threads = 0;
++  pool->young_objects = NULL;
++  pool->color = flip_color (pool->color);
+ }
+ 
++struct pi_list
++{
++  struct pi_list *next;
++  struct port_info *pi;
++};
++
+ void
+ _ports_port_deref_deferred (struct port_info *pi)
+ {
+-  struct ports_sync *s = &pi->bucket->sync;
++  struct ports_threadpool *pool = &pi->bucket->threadpool;
+ 
+   struct pi_list *pl = malloc (sizeof *pl);
+   if (pl == NULL)
+     return;
+   pl->pi = pi;
+ 
+-  pthread_spin_lock (&s->lock);
+-  pl->next = s->young_objects;
+-  s->young_objects = pl;
+-  if (s->old_threads == 0)
++  pthread_spin_lock (&pool->lock);
++  pl->next = pool->young_objects;
++  pool->young_objects = pl;
++  if (pool->old_threads == 0)
+     {
+-      assert (s->old_objects == NULL);
+-      flip_generations (s);
++      assert (pool->old_objects == NULL);
++      flip_generations (pool);
+     }
+-  pthread_spin_unlock (&s->lock);
++  pthread_spin_unlock (&pool->lock);
+ }
+ 
+ void
+ _ports_thread_online (struct port_bucket *bucket,
+-		      struct ports_thread *t)
++		      struct ports_thread *thread)
+ {
+-  struct ports_sync *s = &bucket->sync;
+-  pthread_spin_lock (&s->lock);
+-  t->color = flip_color (s->color);
+-  s->young_threads += 1;
+-  pthread_spin_unlock (&s->lock);
++  struct ports_threadpool *pool = &bucket->threadpool;
++  pthread_spin_lock (&pool->lock);
++  thread->color = flip_color (pool->color);
++  pool->young_threads += 1;
++  pthread_spin_unlock (&pool->lock);
+ }
+ 
+ void
+ _ports_thread_quiescent (struct port_bucket *bucket,
+-			 struct ports_thread *t)
++			 struct ports_thread *thread)
+ {
+-  struct ports_sync *s = &bucket->sync;
++  struct ports_threadpool *pool = &bucket->threadpool;
+   struct pi_list *free_list = NULL, *p;
+-  assert (COLOR_VALID (t->color));
++  assert (valid_color (thread->color));
+ 
+-  pthread_spin_lock (&s->lock);
+-  if (t->color == s->color)
++  pthread_spin_lock (&pool->lock);
++  if (thread->color == pool->color)
+     {
+-      s->old_threads -= 1;
+-      s->young_threads += 1;
+-      t->color = flip_color (t->color);
++      pool->old_threads -= 1;
++      pool->young_threads += 1;
++      thread->color = flip_color (thread->color);
+ 
+-      if (s->old_threads == 0)
++      if (pool->old_threads == 0)
+ 	{
+-	  free_list = s->old_objects;
+-	  flip_generations (s);
++	  free_list = pool->old_objects;
++	  flip_generations (pool);
+ 	}
+     }
+-  pthread_spin_unlock (&s->lock);
++  pthread_spin_unlock (&pool->lock);
+ 
+   if (free_list)
+-    error (0, 0, "dereferencing %p, my color is %d", free_list, t->color);
++    error (0, 0, "dereferencing %p, my color is %d", free_list, thread->color);
+ 
+   for (p = free_list; p;)
+     {
+@@ -111,19 +122,19 @@ _ports_thread_quiescent (struct port_bucket *bucket,
+ 
+ void
+ _ports_thread_offline (struct port_bucket *bucket,
+-		       struct ports_thread *t)
++		       struct ports_thread *thread)
+ {
+-  struct ports_sync *s = &bucket->sync;
+-  assert (COLOR_VALID (t->color));
++  struct ports_threadpool *pool = &bucket->threadpool;
++  assert (valid_color (thread->color));
+  retry:
+-  pthread_spin_lock (&s->lock);
+-  if (t->color == s->color)
++  pthread_spin_lock (&pool->lock);
++  if (thread->color == pool->color)
+     {
+-      pthread_spin_unlock (&s->lock);
+-      _ports_thread_quiescent (bucket, t);
++      pthread_spin_unlock (&pool->lock);
++      _ports_thread_quiescent (bucket, thread);
+       goto retry;
+     }
+-  t->color = COLOR_NONE;
+-  s->young_threads -= 1;
+-  pthread_spin_unlock (&s->lock);
++  thread->color = COLOR_INVALID;
++  pool->young_threads -= 1;
++  pthread_spin_unlock (&pool->lock);
+ }
+diff --git a/libports/port-deref-deferred.h b/libports/port-deref-deferred.h
+index 6586c81..6c208fd 100644
+--- a/libports/port-deref-deferred.h
++++ b/libports/port-deref-deferred.h
+@@ -1,19 +1,13 @@
+ #ifndef	_HURD_PORTS_DEREF_DEFERRED_
+ #define	_HURD_PORTS_DEREF_DEFERRED_
+ 
+-enum def_color { COLOR_NONE, COLOR_BLACK, COLOR_WHITE };
++struct pi_list;
+ 
+-struct pi_list
+-{
+-  struct pi_list *next;
+-  struct port_info *pi;
+-};
+-
+-struct ports_sync
++struct ports_threadpool
+ {
+   pthread_spinlock_t lock;
+ 
+-  enum def_color color;
++  unsigned int color;
+ 
+   size_t old_threads;
+   struct pi_list *old_objects;
+@@ -24,9 +18,9 @@ struct ports_sync
+ 
+ struct ports_thread
+ {
+-  enum def_color color;
++  unsigned int color;
+ };
+ 
+-void _ports_sync_init (struct ports_sync *s);
++void _ports_threadpool_init (struct ports_threadpool *);
+ 
+ #endif	/* _HURD_PORTS_DEREF_DEFERRED_ */
+diff --git a/libports/ports.h b/libports/ports.h
+index c047a1a..dd396f2 100644
+--- a/libports/ports.h
++++ b/libports/ports.h
+@@ -75,7 +75,7 @@ struct port_bucket
+   int rpcs;
+   int flags;
+   int count;
+-  struct ports_sync sync;
++  struct ports_threadpool threadpool;
+ };
+ /* FLAGS above are the following: */
+ #define PORT_BUCKET_INHIBITED	PORTS_INHIBITED
+-- 
+2.1.4
+
diff --git a/debian/patches/series b/debian/patches/series
index 49de301c..5d6f0e28 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -46,3 +46,7 @@ merge-me-0002-startup-faster-reboots.patch
 thomas_term.patch
 ajoin.patch
 proc_disable_new_task_notifications.patch
+0001-libports-use-protected-payloads-to-optimize-the-obje.patch
+0002-xxx-fix-and-assert-reached.patch
+0003-new-design.patch
+0004-renamed-stuff.patch