Package: glibc / 2.28-10

hurd-i386/tg-hurdsig-global-dispositions.diff Patch series | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
Subject: [PATCH] Global signal dispositions.

Although they should not change the
default behaviors of signals for cthread programs, these patches add
new functions which can be used by libpthread to enable
POSIX-conforming behavior of signals on a per-thread basis.

YYYY-MM-DD  Jeremie Koenig  <jk@jk.fr.eu.org>

    e407ae3 Hurd signals: implement global signal dispositions
    38eb4b3 Hurd signals: provide a sigstate destructor
    344dfd6 Hurd signals: fix sigwait() for global signals
    fb055f2 Hurd signals: fix global untraced signals.

YYYY-MM-DD  Thomas Schwinge  <thomas@codesourcery.com>

	* sysdeps/mach/hurd/fork.c (__fork): In the child, reinitialize
	the global sigstate's lock.

This is work in progress.

This cures an issue that would very rarely cause a deadlock in the child
in fork, tries to unlock ss' critical section lock at the end of fork.
This will typically (always?) be observed in /bin/sh, which is not
surprising as that is the foremost caller of fork.

To reproduce an intermediate state, add an endless loop if
_hurd_global_sigstate is locked after __proc_dostop (cast through
volatile); that is, while still being in the fork's parent process.

When that triggers (use the libtool testsuite), the signal thread has
already locked ss (which is _hurd_global_sigstate), and is stuck at
hurdsig.c:685 in post_signal, trying to lock _hurd_siglock (which the
main thread already has locked and keeps locked until after
__task_create).  This is the case that ss->thread == MACH_PORT_NULL, that
is, a global signal.  In the main thread, between __proc_dostop and
__task_create is the __thread_abort call on the signal thread which would
abort any current kernel operation (but leave ss locked).  Later in fork,
in the parent, when _hurd_siglock is unlocked in fork, the parent's
signal thread can proceed and will unlock eventually the global sigstate.
In the client, _hurd_siglock will likewise be unlocked, but the global
sigstate never will be, as the client's signal thread has been configured
to restart execution from _hurd_msgport_receive.  Thus, when the child
tries to unlock ss' critical section lock at the end of fork, it will
first lock the global sigstate, will spin trying to lock it, which can
never be successful, and we get our deadlock.

Options seem to be:

  * Move the locking of _hurd_siglock earlier in post_signal -- but that
    may generally impact performance, if this locking isn't generally
    needed anyway?

    On the other hand, would it actually make sense to wait here until we
    are not any longer in a critical section (which is meant to disable
    signal delivery anyway (but not for preempted signals?))?

  * Clear the global sigstate in the fork's child with the rationale that
    we're anyway restarting the signal thread from a clean state.  This
    has now been implemented.

Why has this problem not been observed before Jérémie's patches?  (Or has
it?  Perhaps even more rarely?)  In _S_msg_sig_post, the signal is now
posted to a *global receiver thread*, whereas previously it was posted to
the *designated signal-receiving thread*.  The latter one was in a
critical section in fork, so didn't try to handle the signal until after
leaving the critical section?  (Not completely analyzed and verified.)

Another question is what the signal is that is being received
during/around the time __proc_dostop executes.

---
 hurd/ctty-input.c                   |   16 +-
 hurd/ctty-output.c                  |   16 +-
 hurd/hurd/signal.h                  |   38 +++--
 hurd/hurdexec.c                     |    9 -
 hurd/hurdmsg.c                      |   24 ---
 hurd/hurdsig.c                      |  272 +++++++++++++++++++++++++++---------
 sysdeps/mach/hurd/fork.c            |   24 ++-
 sysdeps/mach/hurd/i386/sigreturn.c  |   10 -
 sysdeps/mach/hurd/i386/trampoline.c |    6 
 sysdeps/mach/hurd/sigaction.c       |   16 +-
 sysdeps/mach/hurd/sigpending.c      |    6 
 sysdeps/mach/hurd/sigprocmask.c     |    8 -
 sysdeps/mach/hurd/sigsuspend.c      |   15 +
 sysdeps/mach/hurd/sigwait.c         |   21 +-
 sysdeps/mach/hurd/spawni.c          |   23 +--
 15 files changed, 348 insertions(+), 156 deletions(-)

--- a/hurd/ctty-input.c
+++ b/hurd/ctty-input.c
@@ -43,12 +43,15 @@
 	  else
 	    {
 	      struct hurd_sigstate *ss = _hurd_self_sigstate ();
-	      __spin_lock (&ss->lock);
+	      struct sigaction *actions;
+
+	      _hurd_sigstate_lock (ss);
+	      actions = _hurd_sigstate_actions (ss);
 	      if (__sigismember (&ss->blocked, SIGTTIN) ||
-		  ss->actions[SIGTTIN].sa_handler == SIG_IGN)
+		  actions[SIGTTIN].sa_handler == SIG_IGN)
 		/* We are blocking or ignoring SIGTTIN.  Just fail.  */
 		err = EIO;
-	      __spin_unlock (&ss->lock);
+	      _hurd_sigstate_unlock (ss);
 
 	      if (err == EBACKGROUND)
 		{
@@ -65,10 +68,11 @@
 		     SIGTTIN or resumed after being stopped.  Now this is
 		     still a "system call", so check to see if we should
 		  restart it.  */
-		  __spin_lock (&ss->lock);
-		  if (!(ss->actions[SIGTTIN].sa_flags & SA_RESTART))
+		  _hurd_sigstate_lock (ss);
+		  actions = _hurd_sigstate_actions (ss);
+		  if (!(actions[SIGTTIN].sa_flags & SA_RESTART))
 		    err = EINTR;
-		  __spin_unlock (&ss->lock);
+		  _hurd_sigstate_unlock (ss);
 		}
 	    }
 	}
--- a/hurd/ctty-output.c
+++ b/hurd/ctty-output.c
@@ -34,16 +34,19 @@
 
       do
 	{
+	  struct sigaction *actions;
+
 	  /* Don't use the ctty io port if we are blocking or ignoring
 	     SIGTTOU.  We redo this check at the top of the loop in case
 	     the signal handler changed the state.  */
-	  __spin_lock (&ss->lock);
+	  _hurd_sigstate_lock (ss);
+	  actions = _hurd_sigstate_actions (ss);
 	  if (__sigismember (&ss->blocked, SIGTTOU) ||
-	      ss->actions[SIGTTOU].sa_handler == SIG_IGN)
+	      actions[SIGTTOU].sa_handler == SIG_IGN)
 	    err = EIO;
 	  else
 	    err = 0;
-	  __spin_unlock (&ss->lock);
+	  _hurd_sigstate_unlock (ss);
 
 	  if (err)
 	    return (*rpc) (port);
@@ -70,10 +73,11 @@
 		     SIGTTOU or resumed after being stopped.  Now this is
 		     still a "system call", so check to see if we should
 		  restart it.  */
-		  __spin_lock (&ss->lock);
-		  if (!(ss->actions[SIGTTOU].sa_flags & SA_RESTART))
+		  _hurd_sigstate_lock (ss);
+		  actions = _hurd_sigstate_actions (ss);
+		  if (!(actions[SIGTTOU].sa_flags & SA_RESTART))
 		    err = EINTR;
-		  __spin_unlock (&ss->lock);
+		  _hurd_sigstate_unlock (ss);
 		}
 	    }
 	  /* If the last RPC generated a SIGTTOU, loop to try it again.  */
--- a/hurd/hurd/signal.h
+++ b/hurd/hurd/signal.h
@@ -73,7 +73,13 @@
 
     sigset_t blocked;		/* What signals are blocked.  */
     sigset_t pending;		/* Pending signals, possibly blocked.  */
+
+    /* Signal handlers.  ACTIONS[0] is used to mark the threads with POSIX
+       semantics: if sa_handler is SIG_IGN instead of SIG_DFL, this thread
+       will receive global signals and use the process-wide action vector
+       instead of this one.  */
     struct sigaction actions[_NSIG];
+
     stack_t sigaltstack;
 
     /* Chain of thread-local signal preemptors; see <hurd/sigpreempt.h>.
@@ -129,6 +135,26 @@
 	by different threads.  */
      __attribute__ ((__const__));
 
+/* Process-wide signal state.  */
+
+extern struct hurd_sigstate *_hurd_global_sigstate;
+
+/* Mark the given thread as a process-wide signal receiver.  */
+
+extern void _hurd_sigstate_set_global_rcv (struct hurd_sigstate *ss);
+
+/* A thread can either use its own action vector and pending signal set
+   or use the global ones, depending on wether it has been marked as a
+   global receiver. The accessors below take that into account.  */
+
+extern void _hurd_sigstate_lock (struct hurd_sigstate *ss);
+extern struct sigaction *_hurd_sigstate_actions (struct hurd_sigstate *ss);
+extern sigset_t _hurd_sigstate_pending (const struct hurd_sigstate *ss);
+extern void _hurd_sigstate_unlock (struct hurd_sigstate *ss);
+
+/* Used by libpthread to remove stale sigstate structures.  */
+extern void _hurd_sigstate_delete (thread_t thread);
+
 #ifndef _HURD_SIGNAL_H_EXTERN_INLINE
 #define _HURD_SIGNAL_H_EXTERN_INLINE __extern_inline
 #endif
@@ -154,12 +180,6 @@
 
 extern mach_port_t _hurd_msgport;
 
-
-/* Thread to receive process-global signals.  */
-
-extern thread_t _hurd_sigthread;
-
-
 /* Resource limit on core file size.  Enforced by hurdsig.c.  */
 extern int _hurd_core_limit;
 
@@ -222,10 +242,10 @@
       /* It was us who acquired the critical section lock.  Unlock it.  */
       struct hurd_sigstate *ss = (struct hurd_sigstate *) our_lock;
       sigset_t pending;
-      __spin_lock (&ss->lock);
+      _hurd_sigstate_lock (ss);
       __spin_unlock (&ss->critical_section_lock);
-      pending = ss->pending & ~ss->blocked;
-      __spin_unlock (&ss->lock);
+      pending = _hurd_sigstate_pending(ss) & ~ss->blocked;
+      _hurd_sigstate_unlock (ss);
       if (! __sigisemptyset (&pending))
 	/* There are unblocked signals pending, which weren't
 	   delivered because we were in the critical section.
--- a/hurd/hurdexec.c
+++ b/hurd/hurdexec.c
@@ -125,12 +125,13 @@
 
   __spin_lock (&ss->critical_section_lock);
 
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
+  struct sigaction *actions = _hurd_sigstate_actions (ss);
   ints[INIT_SIGMASK] = ss->blocked;
-  ints[INIT_SIGPENDING] = ss->pending;
+  ints[INIT_SIGPENDING] = _hurd_sigstate_pending (ss);
   ints[INIT_SIGIGN] = 0;
   for (i = 1; i < NSIG; ++i)
-    if (ss->actions[i].sa_handler == SIG_IGN)
+    if (actions[i].sa_handler == SIG_IGN)
       ints[INIT_SIGIGN] |= __sigmask (i);
 
   /* We hold the sigstate lock until the exec has failed so that no signal
@@ -141,7 +142,7 @@
      critical section flag avoids anything we call trying to acquire the
      sigstate lock.  */
 
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
 
   /* Pack up the descriptor table to give the new program.  */
   __mutex_lock (&_hurd_dtable_lock);
--- a/hurd/hurdmsg.c
+++ b/hurd/hurdmsg.c
@@ -121,17 +121,9 @@
     case INIT_UMASK:
       *value = _hurd_umask;
       return 0;
-    case INIT_SIGMASK:
-      {
-	struct hurd_sigstate *ss = _hurd_thread_sigstate (_hurd_sigthread);
-	__spin_lock (&ss->lock);
-	*value = ss->blocked;
-	__spin_unlock (&ss->lock);
-	return 0;
-      }
     case INIT_SIGPENDING:
       {
-	struct hurd_sigstate *ss = _hurd_thread_sigstate (_hurd_sigthread);
+	struct hurd_sigstate *ss = _hurd_global_sigstate;
 	__spin_lock (&ss->lock);
 	*value = ss->pending;
 	__spin_unlock (&ss->lock);
@@ -139,7 +131,7 @@
       }
     case INIT_SIGIGN:
       {
-	struct hurd_sigstate *ss = _hurd_thread_sigstate (_hurd_sigthread);
+	struct hurd_sigstate *ss = _hurd_global_sigstate;
 	sigset_t ign;
 	int sig;
 	__spin_lock (&ss->lock);
@@ -207,17 +199,9 @@
       return 0;
 
       /* These are pretty odd things to do.  But you asked for it.  */
-    case INIT_SIGMASK:
-      {
-	struct hurd_sigstate *ss = _hurd_thread_sigstate (_hurd_sigthread);
-	__spin_lock (&ss->lock);
-	ss->blocked = value;
-	__spin_unlock (&ss->lock);
-	return 0;
-      }
     case INIT_SIGPENDING:
       {
-	struct hurd_sigstate *ss = _hurd_thread_sigstate (_hurd_sigthread);
+	struct hurd_sigstate *ss = _hurd_global_sigstate;
 	__spin_lock (&ss->lock);
 	ss->pending = value;
 	__spin_unlock (&ss->lock);
@@ -225,7 +209,7 @@
       }
     case INIT_SIGIGN:
       {
-	struct hurd_sigstate *ss = _hurd_thread_sigstate (_hurd_sigthread);
+	struct hurd_sigstate *ss = _hurd_global_sigstate;
 	int sig;
 	const sigset_t ign = value;
 	__spin_lock (&ss->lock);
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -46,9 +46,6 @@
 /* Thread listening on it.  */
 thread_t _hurd_msgport_thread;
 
-/* Thread which receives task-global signals.  */
-thread_t _hurd_sigthread;
-
 /* These are set up by _hurdsig_init.  */
 unsigned long int __hurd_sigthread_stack_base;
 unsigned long int __hurd_sigthread_stack_end;
@@ -56,6 +53,9 @@
 /* Linked-list of per-thread signal state.  */
 struct hurd_sigstate *_hurd_sigstates;
 
+/* Sigstate for the task-global signals.  */
+struct hurd_sigstate *_hurd_global_sigstate;
+
 /* Timeout for RPC's after interrupt_operation. */
 mach_msg_timeout_t _hurd_interrupted_rpc_timeout = 3000;
 
@@ -84,7 +84,7 @@
     {
       ss = malloc (sizeof (*ss));
       if (ss == NULL)
-	__libc_fatal ("hurd: Can't allocate thread sigstate\n");
+	__libc_fatal ("hurd: Can't allocate sigstate\n");
       ss->thread = thread;
       __spin_lock_init (&ss->lock);
 
@@ -97,16 +97,19 @@
       ss->intr_port = MACH_PORT_NULL;
       ss->context = NULL;
 
-      /* Initialize the sigaction vector from the default signal receiving
-	 thread's state, and its from the system defaults.  */
-      if (thread == _hurd_sigthread)
-	default_sigaction (ss->actions);
+      if (thread == MACH_PORT_NULL)
+	{
+	  /* Process-wide sigstate, use the system defaults.  */
+	  default_sigaction (ss->actions);
+
+	  /* The global sigstate is not added to the _hurd_sigstates list.
+	     It is created with _hurd_thread_sigstate (MACH_PORT_NULL)
+	     but should be accessed through _hurd_global_sigstate.  */
+	}
       else
 	{
-	  struct hurd_sigstate *s;
-	  for (s = _hurd_sigstates; s != NULL; s = s->next)
-	    if (s->thread == _hurd_sigthread)
-	      break;
+	  /* Use the global actions as a default for new threads.  */
+	  struct hurd_sigstate *s = _hurd_global_sigstate;
 	  if (s)
 	    {
 	      __spin_lock (&s->lock);
@@ -115,15 +118,109 @@
 	    }
 	  else
 	    default_sigaction (ss->actions);
-	}
 
-      ss->next = _hurd_sigstates;
-      _hurd_sigstates = ss;
+	  ss->next = _hurd_sigstates;
+	  _hurd_sigstates = ss;
+	}
     }
   __mutex_unlock (&_hurd_siglock);
   return ss;
 }
 libc_hidden_def (_hurd_thread_sigstate)
+
+/* Destroy a sigstate structure.  Called by libpthread just before the
+ * corresponding thread is terminated (the kernel thread port must remain valid
+ * until this function is called.) */
+void
+_hurd_sigstate_delete (thread_t thread)
+{
+  struct hurd_sigstate **ssp, *ss;
+
+  __mutex_lock (&_hurd_siglock);
+  for (ssp = &_hurd_sigstates; *ssp; ssp = &(*ssp)->next)
+    if ((*ssp)->thread == thread)
+      break;
+
+  ss = *ssp;
+  if (ss)
+    *ssp = ss->next;
+
+  __mutex_unlock (&_hurd_siglock);
+  if (ss)
+    free (ss);
+}
+
+/* Make SS a global receiver, with pthread signal semantics.  */
+void
+_hurd_sigstate_set_global_rcv (struct hurd_sigstate *ss)
+{
+  assert (ss->thread != MACH_PORT_NULL);
+  ss->actions[0].sa_handler = SIG_IGN;
+}
+
+/* Check whether SS is a global receiver.  */
+static int
+sigstate_is_global_rcv (const struct hurd_sigstate *ss)
+{
+  return ss->actions[0].sa_handler == SIG_IGN;
+}
+
+/* Lock/unlock a hurd_sigstate structure.  If the accessors below require
+   it, the global sigstate will be locked as well.  */
+void
+_hurd_sigstate_lock (struct hurd_sigstate *ss)
+{
+  if (sigstate_is_global_rcv (ss))
+    __spin_lock (&_hurd_global_sigstate->lock);
+  __spin_lock (&ss->lock);
+}
+void
+_hurd_sigstate_unlock (struct hurd_sigstate *ss)
+{
+  __spin_unlock (&ss->lock);
+  if (sigstate_is_global_rcv (ss))
+    __spin_unlock (&_hurd_global_sigstate->lock);
+}
+
+/* Retreive a thread's full set of pending signals, including the global
+   ones if appropriate.  SS must be locked.  */
+sigset_t
+_hurd_sigstate_pending (const struct hurd_sigstate *ss)
+{
+  sigset_t pending = ss->pending;
+  if (sigstate_is_global_rcv (ss))
+    __sigorset (&pending, &pending, &_hurd_global_sigstate->pending);
+  return pending;
+}
+
+/* Clear a pending signal and return the associated detailed
+   signal information. SS must be locked, and must have signal SIGNO
+   pending, either directly or through the global sigstate.  */
+static struct hurd_signal_detail
+sigstate_clear_pending (struct hurd_sigstate *ss, int signo)
+{
+  if (sigstate_is_global_rcv (ss)
+      && __sigismember (&_hurd_global_sigstate->pending, signo))
+    {
+      __sigdelset (&_hurd_global_sigstate->pending, signo);
+      return _hurd_global_sigstate->pending_data[signo];
+    }
+
+  assert (__sigismember (&ss->pending, signo));
+  __sigdelset (&ss->pending, signo);
+  return ss->pending_data[signo];
+}
+
+/* Retreive a thread's action vector.  SS must be locked.  */
+struct sigaction *
+_hurd_sigstate_actions (struct hurd_sigstate *ss)
+{
+  if (sigstate_is_global_rcv (ss))
+    return _hurd_global_sigstate->actions;
+  else
+    return ss->actions;
+}
+
 
 /* Signal delivery itself is on this page.  */
 
@@ -218,6 +315,8 @@
 abort_thread (struct hurd_sigstate *ss, struct machine_thread_all_state *state,
 	      void (*reply) (void))
 {
+  assert (ss->thread != MACH_PORT_NULL);
+
   if (!(state->set & THREAD_ABORTED))
     {
       error_t err = __thread_abort (ss->thread);
@@ -364,7 +463,7 @@
 	   call above will retry their RPCs unless we clear SS->intr_port.
 	   So we clear it for the thread taking a signal when SA_RESTART is
 	   clear, so that its call returns EINTR.  */
-	if (! signo || !(ss->actions[signo].sa_flags & SA_RESTART))
+	if (! signo || !(_hurd_sigstate_actions (ss) [signo].sa_flags & SA_RESTART))
 	  ss->intr_port = MACH_PORT_NULL;
       }
 
@@ -487,9 +586,11 @@
 		  sigmask (SIGSTOP) | sigmask (SIGTSTP))
 
 /* Actual delivery of a single signal.  Called with SS unlocked.  When
-   the signal is delivered, return 1 with SS locked.  If the signal is
-   being traced, return 0 with SS unlocked.   */
-static int
+   the signal is delivered, return SS, locked (or, if SS was originally
+   _hurd_global_sigstate, the sigstate of the actual thread the signal
+   was delivered to).  If the signal is being traced, return NULL with
+   SS unlocked.   */
+static struct hurd_sigstate *
 post_signal (struct hurd_sigstate *ss,
 	     int signo, struct hurd_signal_detail *detail,
 	     int untraced, void (*reply) (void))
@@ -542,8 +643,12 @@
       assert_perror (err);
       for (i = 0; i < nthreads; ++i)
 	{
-	  if (threads[i] != _hurd_msgport_thread &&
-	      (act != handle || threads[i] != ss->thread))
+	  if (act == handle && threads[i] == ss->thread)
+	    {
+	      /* The thread that will run the handler is kept suspended.  */
+	      ss_suspended = 1;
+	    }
+	  else if (threads[i] != _hurd_msgport_thread)
 	    {
 	      err = __thread_resume (threads[i]);
 	      assert_perror (err);
@@ -556,9 +661,6 @@
 		       (vm_address_t) threads,
 		       nthreads * sizeof *threads);
       _hurd_stopped = 0;
-      if (act == handle)
-	/* The thread that will run the handler is already suspended.  */
-	ss_suspended = 1;
     }
 
   error_t err;
@@ -574,13 +676,43 @@
 	}
 
       /* This call is just to check for pending signals.  */
-      __spin_lock (&ss->lock);
-      return 1;
+      _hurd_sigstate_lock (ss);
+      return ss;
     }
 
   thread_state.set = 0;		/* We know nothing.  */
 
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
+
+  /* If this is a global signal, try to find a thread ready to accept
+     it right away.  This is especially important for untraced signals,
+     since going through the global pending mask would de-untrace them.  */
+  if (ss->thread == MACH_PORT_NULL)
+  {
+    struct hurd_sigstate *rss;
+
+    __mutex_lock (&_hurd_siglock);
+    for (rss = _hurd_sigstates; rss != NULL; rss = rss->next)
+      {
+	if (! sigstate_is_global_rcv (rss))
+	  continue;
+
+	/* The global sigstate is already locked.  */
+	__spin_lock (&rss->lock);
+	if (! __sigismember (&rss->blocked, signo))
+	  {
+	    ss = rss;
+	    break;
+	  }
+	__spin_unlock (&rss->lock);
+      }
+    __mutex_unlock (&_hurd_siglock);
+  }
+
+  /* We want the preemptors to be able to update the blocking mask
+     without affecting the delivery of this signal, so we save the
+     current value to test against later.  */
+  sigset_t blocked = ss->blocked;
 
   /* Check for a preempted signal.  Preempted signals can arrive during
      critical sections.  */
@@ -638,12 +770,12 @@
 	    mark_pending ();
 	  else
 	    suspend ();
-	  __spin_unlock (&ss->lock);
+	  _hurd_sigstate_unlock (ss);
 	  reply ();
-	  return 0;
+	  return NULL;
 	}
 
-      handler = ss->actions[signo].sa_handler;
+      handler = _hurd_sigstate_actions (ss) [signo].sa_handler;
 
       if (handler == SIG_DFL)
 	/* Figure out the default action for this signal.  */
@@ -737,7 +869,7 @@
 
   /* Handle receipt of a blocked signal, or any signal while stopped.  */
   if (act != ignore &&		/* Signals ignored now are forgotten now.  */
-      __sigismember (&ss->blocked, signo) ||
+      __sigismember (&blocked, signo) ||
       (signo != SIGKILL && _hurd_stopped))
     {
       mark_pending ();
@@ -773,6 +905,7 @@
 	 now's the time to set it going. */
       if (ss_suspended)
 	{
+	  assert (ss->thread != MACH_PORT_NULL);
 	  err = __thread_resume (ss->thread);
 	  assert_perror (err);
 	  ss_suspended = 0;
@@ -817,6 +950,8 @@
 	struct sigcontext *scp, ocontext;
 	int wait_for_reply, state_changed;
 
+	assert (ss->thread != MACH_PORT_NULL);
+
 	/* Stop the thread and abort its pending RPC operations.  */
 	if (! ss_suspended)
 	  {
@@ -953,23 +1088,25 @@
 	    }
 	}
 
+	struct sigaction *action = & _hurd_sigstate_actions (ss) [signo];
+
 	/* Backdoor extra argument to signal handler.  */
 	scp->sc_error = detail->error;
 
 	/* Block requested signals while running the handler.  */
 	scp->sc_mask = ss->blocked;
-	__sigorset (&ss->blocked, &ss->blocked, &ss->actions[signo].sa_mask);
+	__sigorset (&ss->blocked, &ss->blocked, &action->sa_mask);
 
 	/* Also block SIGNO unless we're asked not to.  */
-	if (! (ss->actions[signo].sa_flags & (SA_RESETHAND | SA_NODEFER)))
+	if (! (action->sa_flags & (SA_RESETHAND | SA_NODEFER)))
 	  __sigaddset (&ss->blocked, signo);
 
 	/* Reset to SIG_DFL if requested.  SIGILL and SIGTRAP cannot
            be automatically reset when delivered; the system silently
            enforces this restriction.  */
-	if (ss->actions[signo].sa_flags & SA_RESETHAND
+	if (action->sa_flags & SA_RESETHAND
 	    && signo != SIGILL && signo != SIGTRAP)
-	  ss->actions[signo].sa_handler = SIG_DFL;
+	  action->sa_handler = SIG_DFL;
 
 	/* Any sigsuspend call must return after the handler does.  */
 	wake_sigsuspend (ss);
@@ -987,7 +1124,7 @@
       }
     }
 
-  return 1;
+  return ss;
 }
 
 /* Return the set of pending signals in SS which should be delivered. */
@@ -1002,7 +1139,7 @@
   if (_hurd_stopped || __spin_lock_locked (&ss->critical_section_lock))
     return 0;
 
-  return ss->pending & ~ss->blocked;
+  return _hurd_sigstate_pending (ss) & ~ss->blocked;
 }
 
 /* Post the specified pending signals in SS and return 1.  If one of
@@ -1014,12 +1151,15 @@
   int signo;
   struct hurd_signal_detail detail;
 
+  /* Make sure SS corresponds to an actual thread, since we assume it won't
+     change in post_signal. */
+  assert (ss->thread != MACH_PORT_NULL);
+
   for (signo = 1; signo < NSIG; ++signo)
     if (__sigismember (&pending, signo))
       {
-	__sigdelset (&ss->pending, signo);
-	detail = ss->pending_data[signo];
-	__spin_unlock (&ss->lock);
+	detail = sigstate_clear_pending (ss, signo);
+	_hurd_sigstate_unlock (ss);
 
 	/* Will reacquire the lock, except if the signal is traced.  */
 	if (! post_signal (ss, signo, &detail, 0, reply))
@@ -1027,7 +1167,7 @@
       }
 
   /* No more signals pending; SS->lock is still locked.  */
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
 
   return 1;
 }
@@ -1045,14 +1185,14 @@
       __mutex_lock (&_hurd_siglock);
       for (ss = _hurd_sigstates; ss != NULL; ss = ss->next)
         {
-	  __spin_lock (&ss->lock);
+	  _hurd_sigstate_lock (ss);
 
 	  pending = pending_signals (ss);
 	  if (pending)
 	    /* post_pending() below will unlock SS. */
 	    break;
 
-	  __spin_unlock (&ss->lock);
+	  _hurd_sigstate_unlock (ss);
 	}
       __mutex_unlock (&_hurd_siglock);
 
@@ -1085,11 +1225,12 @@
 	assert_perror (err);
     }
 
-  if (! post_signal (ss, signo, detail, untraced, reply))
+  ss = post_signal (ss, signo, detail, untraced, reply);
+  if (! ss)
     return;
 
   /* The signal was neither fatal nor traced.  We still hold SS->lock.  */
-  if (signo != 0)
+  if (signo != 0 && ss->thread != MACH_PORT_NULL)
     {
       /* The signal has either been ignored or is now being handled.  We can
 	 consider it delivered and reply to the killer.  */
@@ -1101,8 +1242,9 @@
     }
   else
     {
-      /* We need to check for pending signals for all threads.  */
-      __spin_unlock (&ss->lock);
+      /* If this was a process-wide signal or a poll request, we need
+	 to check for pending signals for all threads.  */
+      _hurd_sigstate_unlock (ss);
       if (! post_all_pending_signals (reply))
 	return;
 
@@ -1228,9 +1370,10 @@
   d.code = sigcode;
   d.exc = 0;
 
-  /* Post the signal to the designated signal-receiving thread.  This will
-     reply when the signal can be considered delivered.  */
-  _hurd_internal_post_signal (_hurd_thread_sigstate (_hurd_sigthread),
+  /* Post the signal to a global receiver thread (or mark it pending in
+     the global sigstate).  This will reply when the signal can be
+     considered delivered.  */
+  _hurd_internal_post_signal (_hurd_global_sigstate,
 			      signo, &d, reply_port, reply_port_type,
 			      0); /* Stop if traced.  */
 
@@ -1258,7 +1401,7 @@
 
   /* Post the signal to the designated signal-receiving thread.  This will
      reply when the signal can be considered delivered.  */
-  _hurd_internal_post_signal (_hurd_thread_sigstate (_hurd_sigthread),
+  _hurd_internal_post_signal (_hurd_global_sigstate,
 			      signo, &d, reply_port, reply_port_type,
 			      1); /* Untraced flag. */
 
@@ -1269,8 +1412,8 @@
 
 #include <mach/task_special_ports.h>
 
-/* Initialize the message port and _hurd_sigthread and start the signal
-   thread.  */
+/* Initialize the message port, _hurd_global_sigstate, and start the
+   signal thread.  */
 
 void
 _hurdsig_init (const int *intarray, size_t intarraysize)
@@ -1293,27 +1436,34 @@
 				  MACH_MSG_TYPE_MAKE_SEND);
   assert_perror (err);
 
+  /* Initialize the global signal state.  */
+  _hurd_global_sigstate = _hurd_thread_sigstate (MACH_PORT_NULL);
+
+  /* We block all signals, and let actual threads pull them from the
+     pending mask.  */
+  __sigfillset(& _hurd_global_sigstate->blocked);
+
   /* Initialize the main thread's signal state.  */
   ss = _hurd_self_sigstate ();
 
-  /* Copy inherited values from our parent (or pre-exec process state)
-     into the signal settings of the main thread.  */
+  /* Mark it as a process-wide signal receiver.  Threads in this set use
+     the common action vector in _hurd_global_sigstate.  */
+  _hurd_sigstate_set_global_rcv (ss);
+
+  /* Copy inherited signal settings from our parent (or pre-exec process
+     state) */
   if (intarraysize > INIT_SIGMASK)
     ss->blocked = intarray[INIT_SIGMASK];
   if (intarraysize > INIT_SIGPENDING)
-    ss->pending = intarray[INIT_SIGPENDING];
+    _hurd_global_sigstate->pending = intarray[INIT_SIGPENDING];
   if (intarraysize > INIT_SIGIGN && intarray[INIT_SIGIGN] != 0)
     {
       int signo;
       for (signo = 1; signo < NSIG; ++signo)
 	if (intarray[INIT_SIGIGN] & __sigmask(signo))
-	  ss->actions[signo].sa_handler = SIG_IGN;
+	  _hurd_global_sigstate->actions[signo].sa_handler = SIG_IGN;
     }
 
-  /* Set the default thread to receive task-global signals
-     to this one, the main (first) user thread.  */
-  _hurd_sigthread = ss->thread;
-
   /* Start the signal thread listening on the message port.  */
 
 #pragma weak __cthread_fork
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -444,6 +444,7 @@
 	  (err = __mach_port_insert_right (newtask, ss->thread,
 					   thread, MACH_MSG_TYPE_COPY_SEND)))
 	LOSE;
+      /* XXX consumed? (_hurd_sigthread is no more) */
       if (thread_refs > 1 &&
 	  (err = __mach_port_mod_refs (newtask, ss->thread,
 				       MACH_PORT_RIGHT_SEND,
@@ -608,10 +609,6 @@
       for (i = 0; i < _hurd_nports; ++i)
 	__spin_unlock (&_hurd_ports[i].lock);
 
-      /* We are one of the (exactly) two threads in this new task, we
-	 will take the task-global signals.  */
-      _hurd_sigthread = ss->thread;
-
       /* Claim our sigstate structure and unchain the rest: the
 	 threads existed in the parent task but don't exist in this
 	 task (the child process).  Delay freeing them until later
@@ -631,6 +628,25 @@
       ss->next = NULL;
       _hurd_sigstates = ss;
       __mutex_unlock (&_hurd_siglock);
+      /* Earlier on, the global sigstate may have been tainted and now needs to
+         be reinitialized.  Nobody is interested in its present state anymore:
+         we're not, the signal thread will be restarted, and there are no other
+         threads.
+
+         We can't simply allocate a fresh global sigstate here, as
+         _hurd_thread_sigstate will call malloc and that will deadlock trying
+         to determine the current thread's sigstate.  */
+#if 0
+      _hurd_thread_sigstate_init (_hurd_global_sigstate, MACH_PORT_NULL);
+#else
+      /* Only reinitialize the lock -- otherwise we might have to do additional
+         setup as done in hurdsig.c:_hurdsig_init.  */
+      __spin_lock_init (&_hurd_global_sigstate->lock);
+#endif
+
+      /* We are one of the (exactly) two threads in this new task, we
+	 will take the task-global signals.  */
+      _hurd_sigstate_set_global_rcv (ss);
 
       /* Fetch our new process IDs from the proc server.  No need to
 	 refetch our pgrp; it is always inherited from the parent (so
--- a/sysdeps/mach/hurd/i386/sigreturn.c
+++ b/sysdeps/mach/hurd/i386/sigreturn.c
@@ -38,7 +38,7 @@
     }
 
   ss = _hurd_self_sigstate ();
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
 
   /* Remove the link on the `active resources' chain added by
      _hurd_setup_sighandler.  Its purpose was to make sure
@@ -50,19 +50,19 @@
   ss->intr_port = scp->sc_intr_port;
 
   /* Check for pending signals that were blocked by the old set.  */
-  if (ss->pending & ~ss->blocked)
+  if (_hurd_sigstate_pending (ss) & ~ss->blocked)
     {
       /* There are pending signals that just became unblocked.  Wake up the
 	 signal thread to deliver them.  But first, squirrel away SCP where
 	 the signal thread will notice it if it runs another handler, and
 	 arrange to have us called over again in the new reality.  */
       ss->context = scp;
-      __spin_unlock (&ss->lock);
+      _hurd_sigstate_unlock (ss);
       __msg_sig_post (_hurd_msgport, 0, 0, __mach_task_self ());
       /* If a pending signal was handled, sig_post never returned.
 	 If it did return, the pending signal didn't run a handler;
 	 proceed as usual.  */
-      __spin_lock (&ss->lock);
+      _hurd_sigstate_lock (ss);
       ss->context = NULL;
     }
 
@@ -73,7 +73,7 @@
       abort ();
     }
   else
-    __spin_unlock (&ss->lock);
+    _hurd_sigstate_unlock (ss);
 
   /* Destroy the MiG reply port used by the signal handler, and restore the
      reply port in use by the thread when interrupted.  */
--- a/sysdeps/mach/hurd/i386/trampoline.c
+++ b/sysdeps/mach/hurd/i386/trampoline.c
@@ -74,7 +74,11 @@
      interrupted RPC frame.  */
   state->basic.esp = state->basic.uesp;
 
-  if ((ss->actions[signo].sa_flags & SA_ONSTACK) &&
+  /* XXX what if handler != action->handler (for instance, if a signal
+   * preemptor took over) ? */
+  action = & _hurd_sigstate_actions (ss) [signo];
+
+  if ((action->sa_flags & SA_ONSTACK) &&
       !(ss->sigaltstack.ss_flags & (SS_DISABLE|SS_ONSTACK)))
     {
       sigsp = ss->sigaltstack.ss_sp + ss->sigaltstack.ss_size;
--- a/sysdeps/mach/hurd/sigaction.c
+++ b/sysdeps/mach/hurd/sigaction.c
@@ -46,15 +46,15 @@
   ss = _hurd_self_sigstate ();
 
   __spin_lock (&ss->critical_section_lock);
-  __spin_lock (&ss->lock);
-  old = ss->actions[sig];
+  _hurd_sigstate_lock (ss);
+  old = _hurd_sigstate_actions (ss) [sig];
   if (act != NULL)
-    ss->actions[sig] = a;
+    _hurd_sigstate_actions (ss) [sig] = a;
 
   if (act != NULL && sig == SIGCHLD &&
       (a.sa_flags & SA_NOCLDSTOP) != (old.sa_flags & SA_NOCLDSTOP))
     {
-      __spin_unlock (&ss->lock);
+      _hurd_sigstate_unlock (ss);
 
       /* Inform the proc server whether or not it should send us SIGCHLD for
 	 stopped children.  We do this in a critical section so that no
@@ -62,8 +62,8 @@
       __USEPORT (PROC,
 		 __proc_mod_stopchild (port, !(a.sa_flags & SA_NOCLDSTOP)));
 
-      __spin_lock (&ss->lock);
-      pending = ss->pending & ~ss->blocked;
+      _hurd_sigstate_lock (ss);
+      pending = _hurd_sigstate_pending (ss) & ~ss->blocked;
     }
   else if (act != NULL && (a.sa_handler == SIG_IGN || a.sa_handler == SIG_DFL))
     /* We are changing to an action that might be to ignore SIG signals.
@@ -72,11 +72,11 @@
        back and then SIG is unblocked, the signal pending now should not
        arrive.  So wake up the signal thread to check the new state and do
        the right thing.  */
-    pending = ss->pending & __sigmask (sig);
+    pending = _hurd_sigstate_pending (ss) & __sigmask (sig);
   else
     pending = 0;
 
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
   __spin_unlock (&ss->critical_section_lock);
 
   if (pending)
--- a/sysdeps/mach/hurd/sigpending.c
+++ b/sysdeps/mach/hurd/sigpending.c
@@ -36,9 +36,9 @@
     }
 
   ss = _hurd_self_sigstate ();
-  __spin_lock (&ss->lock);
-  pending = ss->pending;
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_lock (ss);
+  pending = _hurd_sigstate_pending (ss);
+  _hurd_sigstate_unlock (ss);
 
   *set = pending;
   return 0;
--- a/sysdeps/mach/hurd/sigprocmask.c
+++ b/sysdeps/mach/hurd/sigprocmask.c
@@ -36,7 +36,7 @@
 
   ss = _hurd_self_sigstate ();
 
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
 
   old = ss->blocked;
 
@@ -57,7 +57,7 @@
 	  break;
 
 	default:
-	  __spin_unlock (&ss->lock);
+	  _hurd_sigstate_unlock (ss);
 	  errno = EINVAL;
 	  return -1;
 	}
@@ -65,9 +65,9 @@
       ss->blocked &= ~_SIG_CANT_MASK;
     }
 
-  pending = ss->pending & ~ss->blocked;
+  pending = _hurd_sigstate_pending (ss) & ~ss->blocked;
 
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
 
   if (oset != NULL)
     *oset = old;
--- a/sysdeps/mach/hurd/sigsuspend.c
+++ b/sysdeps/mach/hurd/sigsuspend.c
@@ -40,7 +40,7 @@
 
   ss = _hurd_self_sigstate ();
 
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
 
   oldmask = ss->blocked;
   if (set != NULL)
@@ -48,11 +48,11 @@
     ss->blocked = newmask & ~_SIG_CANT_MASK;
 
   /* Notice if any pending signals just became unblocked.  */
-  pending = ss->pending & ~ss->blocked;
+  pending = _hurd_sigstate_pending (ss) & ~ss->blocked;
 
   /* Tell the signal thread to message us when a signal arrives.  */
   ss->suspended = wait;
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
 
   if (pending)
     /* Tell the signal thread to check for pending signals.  */
@@ -63,10 +63,11 @@
 	      MACH_MSG_TIMEOUT_NONE, MACH_PORT_NULL);
   __mach_port_destroy (__mach_task_self (), wait);
 
-  __spin_lock (&ss->lock);
-  ss->blocked = oldmask;	/* Restore the old mask.  */
-  pending = ss->pending & ~ss->blocked;	/* Again check for pending signals.  */
-  __spin_unlock (&ss->lock);
+  /* Restore the old mask and check for pending signals again.  */
+  _hurd_sigstate_lock (ss);
+  ss->blocked = oldmask;
+  pending = _hurd_sigstate_pending(ss) & ~ss->blocked;
+  _hurd_sigstate_unlock (ss);
 
   if (pending)
     /* Tell the signal thread to check for pending signals.  */
--- a/sysdeps/mach/hurd/sigwait.c
+++ b/sysdeps/mach/hurd/sigwait.c
@@ -27,7 +27,7 @@
 __sigwait (const sigset_t *set, int *sig)
 {
   struct hurd_sigstate *ss;
-  sigset_t mask, ready;
+  sigset_t mask, ready, blocked;
   int signo = 0;
   struct hurd_signal_preemptor preemptor;
   jmp_buf buf;
@@ -49,8 +49,8 @@
       /* Make sure this is all kosher */
       assert (__sigismember (&mask, signo));
 
-      /* Make sure this signal is unblocked */
-      __sigdelset (&ss->blocked, signo);
+      /* Restore the blocking mask. */
+      ss->blocked = blocked;
 
       return pe->handler;
     }
@@ -71,10 +71,11 @@
     __sigemptyset (&mask);
 
   ss = _hurd_self_sigstate ();
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
 
   /* See if one of these signals is currently pending.  */
-  __sigandset (&ready, &ss->pending, &mask);
+  sigset_t pending = _hurd_sigstate_pending (ss);
+  __sigandset (&ready, &pending, &mask);
   if (! __sigisemptyset (&ready))
     {
       for (signo = 1; signo < NSIG; signo++)
@@ -102,7 +103,11 @@
       preemptor.next = ss->preemptors;
       ss->preemptors = &preemptor;
 
-      __spin_unlock (&ss->lock);
+      /* Unblock the expected signals */
+      blocked = ss->blocked;
+      ss->blocked &= ~mask;
+
+      _hurd_sigstate_unlock (ss);
 
       /* Wait. */
       __mach_msg (&msg, MACH_RCV_MSG, 0, sizeof (msg), wait,
@@ -113,7 +118,7 @@
     {
       assert (signo);
 
-      __spin_lock (&ss->lock);
+      _hurd_sigstate_lock (ss);
 
       /* Delete our preemptor. */
       assert (ss->preemptors == &preemptor);
@@ -122,7 +127,7 @@
 
 
 all_done:
-  spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
 
   __mach_port_destroy (__mach_task_self (), wait);
   *sig = signo;
--- a/sysdeps/mach/hurd/spawni.c
+++ b/sysdeps/mach/hurd/spawni.c
@@ -241,26 +241,29 @@
 
   __spin_lock (&ss->critical_section_lock);
 
-  __spin_lock (&ss->lock);
+  _hurd_sigstate_lock (ss);
   ints[INIT_SIGMASK] = ss->blocked;
-  ints[INIT_SIGPENDING] = ss->pending;
+  ints[INIT_SIGPENDING] = _hurd_sigstate_pending (ss); /* XXX really? */
   ints[INIT_SIGIGN] = 0;
   /* Unless we were asked to reset all handlers to SIG_DFL,
      pass down the set of signals that were set to SIG_IGN.  */
-  if ((flags & POSIX_SPAWN_SETSIGDEF) == 0)
-    for (i = 1; i < NSIG; ++i)
-      if (ss->actions[i].sa_handler == SIG_IGN)
-	ints[INIT_SIGIGN] |= __sigmask (i);
+  {
+    struct sigaction *actions = _hurd_sigstate_actions (ss);
+    if ((flags & POSIX_SPAWN_SETSIGDEF) == 0)
+      for (i = 1; i < NSIG; ++i)
+	if (actions[i].sa_handler == SIG_IGN)
+	  ints[INIT_SIGIGN] |= __sigmask (i);
+  }
 
-  /* We hold the sigstate lock until the exec has failed so that no signal
-     can arrive between when we pack the blocked and ignored signals, and
-     when the exec actually happens.  A signal handler could change what
+  /* We hold the critical section lock until the exec has failed so that no
+     signal can arrive between when we pack the blocked and ignored signals,
+     and when the exec actually happens.  A signal handler could change what
      signals are blocked and ignored.  Either the change will be reflected
      in the exec, or the signal will never be delivered.  Setting the
      critical section flag avoids anything we call trying to acquire the
      sigstate lock.  */
 
-  __spin_unlock (&ss->lock);
+  _hurd_sigstate_unlock (ss);
 
   /* Set signal mask.  */
   if ((flags & POSIX_SPAWN_SETSIGMASK) != 0)