init.c (__nptl_initial_report_events): New variable.

	(__pthread_initialize_minimal_internal): Initialize pd->report_events
	to that.

This patch helps NPTL report TD_CREATE event, so that GDB could catch the
event and update its thread_list.
Link: http://lists.uclibc.org/pipermail/uclibc/2015-April/048921.html
[shengyong:
 - original patch from glibc: commit 7d9d8bd18906fdd17364f372b160d7ab896ce909
 - context adjust
 - update nptl_db/ChangeLog]

Signed-off-by: Roland McGrath <roland@gnu.org>
Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

14 files changed, 217 insertions, 86 deletions

diff --git a/libpthread/nptl_db/ChangeLog b/libpthread/nptl_db/ChangeLog
index 52c849138..92021cbfb 100644
--- a/libpthread/nptl_db/ChangeLog
+++ b/libpthread/nptl_db/ChangeLog
@@ -1,3 +1,26 @@
+2007-05-16  Roland McGrath  <roland@redhat.com>
+
+	* td_thr_get_info.c: Fake the results for TH->th_unique == 0.
+	* td_thr_validate.c: Likewise.
+	* td_thr_setgregs.c: Likewise.
+	* td_thr_setfpregs.c: Likewise.
+	* td_thr_getgregs.c: Likewise.
+	* td_thr_getfpregs.c: Likewise.
+	* td_thr_tlsbase.c: Likewise.
+
+	* structs.def: Add DB_VARIABLE (__nptl_initial_report_events).
+	* db_info.c: Add necessary declaration.
+	* td_thr_event_enable.c: Set __nptl_initial_report_events too.
+
+	* td_ta_thr_iter.c (iterate_thread_list): Make FAKE_EMPTY bool.
+	Use th_unique=0 in fake descriptor before initialization.
+
+	* td_ta_map_lwp2thr.c (__td_ta_lookup_th_unique): New function, broken
+	out of ...
+	(td_ta_map_lwp2thr): ... here, call it.  But don't before __stack_user
+	is initialized, then fake a handle with th_unique=0.
+	* thread_dbP.h: Declare it.
+
 2004-09-09  Roland McGrath  <roland@redhat.com>
 
 	* td_ta_map_lwp2thr.c (td_ta_map_lwp2thr): Don't abort if inferior's
diff --git a/libpthread/nptl_db/db_info.c b/libpthread/nptl_db/db_info.c
index 521ad78a5..a57a053dd 100644
--- a/libpthread/nptl_db/db_info.c
+++ b/libpthread/nptl_db/db_info.c
@@ -1,7 +1,7 @@
 /* This file is included by pthread_create.c to define in libpthread
    all the magic symbols required by libthread_db.
 
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007 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
@@ -37,6 +37,8 @@ typedef struct
 
 typedef struct link_map link_map;
 
+/* Actually static in nptl/init.c, but we only need it for typeof.  */
+extern bool __nptl_initial_report_events;
 
 #define schedparam_sched_priority schedparam.sched_priority
 
diff --git a/libpthread/nptl_db/structs.def b/libpthread/nptl_db/structs.def
index 915867b5b..bb571d45c 100644
--- a/libpthread/nptl_db/structs.def
+++ b/libpthread/nptl_db/structs.def
@@ -1,5 +1,5 @@
 /* List of types and symbols in libpthread examined by libthread_db.
-   Copyright (C) 2003, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2006, 2007 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
@@ -55,6 +55,7 @@ DB_FUNCTION (__nptl_death_event)
 DB_SYMBOL (__nptl_threads_events)
 DB_VARIABLE (__nptl_nthreads)
 DB_VARIABLE (__nptl_last_event)
+DB_VARIABLE (__nptl_initial_report_events)
 
 DB_ARRAY_VARIABLE (__pthread_keys)
 DB_STRUCT (pthread_key_struct)
diff --git a/libpthread/nptl_db/td_ta_map_lwp2thr.c b/libpthread/nptl_db/td_ta_map_lwp2thr.c
index 97097777b..6b4382fbd 100644
--- a/libpthread/nptl_db/td_ta_map_lwp2thr.c
+++ b/libpthread/nptl_db/td_ta_map_lwp2thr.c
@@ -1,5 +1,5 @@
 /* Which thread is running on an LWP?
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007 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
@@ -23,8 +23,8 @@
 
 
 td_err_e
-td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
-		   lwpid_t lwpid, td_thrhandle_t *th)
+__td_ta_lookup_th_unique (const td_thragent_t *ta_arg,
+			  lwpid_t lwpid, td_thrhandle_t *th)
 {
   td_thragent_t *const ta = (td_thragent_t *) ta_arg;
   ps_err_e err;
@@ -117,9 +117,6 @@ td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
 
   switch (ta->ta_howto)
     {
-    case ta_howto_unknown:
-      return TD_DBERR;
-
     default:
       return TD_DBERR;
 
@@ -131,6 +128,7 @@ td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
 				    0, regs, &addr);
       if (terr != TD_OK)
 	return terr;
+
       /* In this descriptor the nelem word is overloaded as the bias.  */
       addr += (int32_t) DB_DESC_NELEM (ta->ta_howto_data.reg);
       th->th_unique = addr;
@@ -142,22 +140,22 @@ td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
       if (&ps_get_thread_area == NULL)
 	return TD_NOCAPAB;
 
-       /* A la x86-64, there is a constant magic index for get_thread_area.  */
-       if (ps_get_thread_area (ta->ph, lwpid,
-			       ta->ta_howto_data.const_thread_area,
-			       &th->th_unique) != PS_OK)
-	 return TD_ERR;	/* XXX Other error value?  */
-       break;
+      /* A la x86-64, there is a magic index for get_thread_area.  */
+      if (ps_get_thread_area (ta->ph, lwpid,
+			      ta->ta_howto_data.const_thread_area,
+			      &th->th_unique) != PS_OK)
+	return TD_ERR;	/* XXX Other error value?  */
+      break;
 
-     case ta_howto_reg_thread_area:
+    case ta_howto_reg_thread_area:
       if (&ps_get_thread_area == NULL)
 	return TD_NOCAPAB;
 
-       /* A la i386, there is a register with an index for get_thread_area.  */
-       if (ps_lgetregs (ta->ph, lwpid, regs) != PS_OK)
-	 return TD_ERR;
-       terr = _td_fetch_value_local (ta, ta->ta_howto_data.reg_thread_area, -1,
-				     0, regs, &addr);
+      /* A la i386, a register holds the index for get_thread_area.  */
+      if (ps_lgetregs (ta->ph, lwpid, regs) != PS_OK)
+	return TD_ERR;
+      terr = _td_fetch_value_local (ta, ta->ta_howto_data.reg_thread_area,
+				    -1, 0, regs, &addr);
       if (terr != TD_OK)
 	return terr;
       /* In this descriptor the nelem word is overloaded as scale factor.  */
@@ -171,7 +169,40 @@ td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
     }
 
   /* Found it.  Now complete the `td_thrhandle_t' object.  */
-  th->th_ta_p = (td_thragent_t *) ta;
+  th->th_ta_p = ta;
 
   return TD_OK;
 }
+
+td_err_e
+td_ta_map_lwp2thr (const td_thragent_t *ta_arg,
+		   lwpid_t lwpid, td_thrhandle_t *th)
+{
+  td_thragent_t *const ta = (td_thragent_t *) ta_arg;
+
+  /* We cannot rely on thread registers and such information at all
+     before __pthread_initialize_minimal has gotten far enough.  They
+     sometimes contain garbage that would confuse us, left by the kernel
+     at exec.  So if it looks like initialization is incomplete, we only
+     fake a special descriptor for the initial thread.  */
+
+  psaddr_t list;
+  td_err_e err = DB_GET_SYMBOL (list, ta, __stack_user);
+  if (err != TD_OK)
+    return err;
+
+  err = DB_GET_FIELD (list, ta, list, list_t, next, 0);
+  if (err != TD_OK)
+    return err;
+
+  if (list == 0)
+    {
+      if (ps_getpid (ta->ph) != lwpid)
+	return TD_ERR;
+      th->th_ta_p = ta;
+      th->th_unique = 0;
+      return TD_OK;
+    }
+
+  return __td_ta_lookup_th_unique (ta_arg, lwpid, th);
+}
diff --git a/libpthread/nptl_db/td_ta_thr_iter.c b/libpthread/nptl_db/td_ta_thr_iter.c
index 1fd02ef87..0f1b2bfd2 100644
--- a/libpthread/nptl_db/td_ta_thr_iter.c
+++ b/libpthread/nptl_db/td_ta_thr_iter.c
@@ -1,5 +1,6 @@
 /* Iterate over a process's threads.
-   Copyright (C) 1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc.
+   Copyright (C) 1999,2000,2001,2002,2003,2004,2007
+	Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -23,7 +24,7 @@
 static td_err_e
 iterate_thread_list (td_thragent_t *ta, td_thr_iter_f *callback,
 		     void *cbdata_p, td_thr_state_e state, int ti_pri,
-		     psaddr_t head, int fake_empty)
+		     psaddr_t head, bool fake_empty)
 {
   td_err_e err;
   psaddr_t next, ofs;
@@ -40,13 +41,13 @@ iterate_thread_list (td_thragent_t *ta, td_thr_iter_f *callback,
 
   if (next == 0 && fake_empty)
     {
-      /* __pthread_initialize_minimal has not run.
-	 There is just the main thread to return.  */
-      td_thrhandle_t th;
-      err = td_ta_map_lwp2thr (ta, ps_getpid (ta->ph), &th);
-      if (err == TD_OK)
-	err = callback (&th, cbdata_p) != 0 ? TD_DBERR : TD_OK;
-      return err;
+      /* __pthread_initialize_minimal has not run.  There is just the main
+	 thread to return.  We cannot rely on its thread register.  They
+	 sometimes contain garbage that would confuse us, left by the
+	 kernel at exec.  So if it looks like initialization is incomplete,
+	 we only fake a special descriptor for the initial thread.  */
+      td_thrhandle_t th = { ta, 0 };
+      return callback (&th, cbdata_p) != 0 ? TD_DBERR : TD_OK;
     }
 
   /* Cache the offset from struct pthread to its list_t member.  */
@@ -135,13 +136,15 @@ td_ta_thr_iter (const td_thragent_t *ta_arg, td_thr_iter_f *callback,
 
   err = DB_GET_SYMBOL (list, ta, __stack_user);
   if (err == TD_OK)
-    err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri, list, 1);
+    err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
+			       list, true);
 
   /* And the threads with stacks allocated by the implementation.  */
   if (err == TD_OK)
     err = DB_GET_SYMBOL (list, ta, stack_used);
   if (err == TD_OK)
-    err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri, list, 0);
+    err = iterate_thread_list (ta, callback, cbdata_p, state, ti_pri,
+			       list, false);
 
   return err;
 }
diff --git a/libpthread/nptl_db/td_thr_event_enable.c b/libpthread/nptl_db/td_thr_event_enable.c
index f49682daa..fd9458011 100644
--- a/libpthread/nptl_db/td_thr_event_enable.c
+++ b/libpthread/nptl_db/td_thr_event_enable.c
@@ -1,5 +1,5 @@
 /* Enable event process-wide.
-   Copyright (C) 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2001, 2002, 2003, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -25,7 +25,25 @@ td_thr_event_enable (const td_thrhandle_t *th, int onoff)
 {
   LOG ("td_thr_event_enable");
 
-  /* Write the new value into the thread data structure.  */
-  return DB_PUT_FIELD (th->th_ta_p, th->th_unique, pthread, report_events, 0,
+  if (th->th_unique != 0)
+    {
+      /* Write the new value into the thread data structure.  */
+      td_err_e err = DB_PUT_FIELD (th->th_ta_p, th->th_unique, pthread,
+				   report_events, 0,
+				   (psaddr_t) 0 + (onoff != 0));
+      if (err != TD_OK)
+	return err;
+
+      /* Just in case we are in the window between initializing __stack_user
+	 and copying from __nptl_initial_report_events, we set it too.
+	 It doesn't hurt to do this for non-initial threads, since it
+	 won't be consulted again anyway.  It would take another fetch
+	 to get the tid and determine this isn't the initial thread,
+	 so just do it always.  */
+    }
+
+  /* We are faking it for the initial thread before its thread
+     descriptor is set up.  */
+  return DB_PUT_VALUE (th->th_ta_p, __nptl_initial_report_events, 0,
 		       (psaddr_t) 0 + (onoff != 0));
 }
diff --git a/libpthread/nptl_db/td_thr_get_info.c b/libpthread/nptl_db/td_thr_get_info.c
index 09d0d1a13..27d5d706b 100644
--- a/libpthread/nptl_db/td_thr_get_info.c
+++ b/libpthread/nptl_db/td_thr_get_info.c
@@ -1,5 +1,5 @@
 /* Get thread information.
-   Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1999,2000,2001,2002,2003,2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -31,35 +31,49 @@ td_thr_get_info (const td_thrhandle_t *th, td_thrinfo_t *infop)
 
   LOG ("td_thr_get_info");
 
-  /* Copy the whole descriptor in once so we can access the several
-     fields locally.  Excess copying in one go is much better than
-     multiple ps_pdread calls.  */
-  err = DB_GET_STRUCT (copy, th->th_ta_p, th->th_unique, pthread);
-  if (err != TD_OK)
-    return err;
-
-  err = DB_GET_FIELD_ADDRESS (tls, th->th_ta_p, th->th_unique,
-			      pthread, specific, 0);
-  if (err != TD_OK)
-    return err;
-
-  err = DB_GET_FIELD_LOCAL (schedpolicy, th->th_ta_p, copy, pthread,
-			    schedpolicy, 0);
-  if (err != TD_OK)
-    return err;
-  err = DB_GET_FIELD_LOCAL (schedprio, th->th_ta_p, copy, pthread,
-			    schedparam_sched_priority, 0);
-  if (err != TD_OK)
-    return err;
-  err = DB_GET_FIELD_LOCAL (tid, th->th_ta_p, copy, pthread, tid, 0);
-  if (err != TD_OK)
-    return err;
-  err = DB_GET_FIELD_LOCAL (cancelhandling, th->th_ta_p, copy, pthread,
-			    cancelhandling, 0);
-  if (err != TD_OK)
-    return err;
-  err = DB_GET_FIELD_LOCAL (report_events, th->th_ta_p, copy, pthread,
-			    report_events, 0);
+  if (th->th_unique == 0)
+    {
+      /* Special case for the main thread before initialization.  */
+      copy = NULL;
+      tls = 0;
+      cancelhandling = 0;
+      schedprio = 0;
+      tid = 0;
+      err = DB_GET_VALUE (report_events, th->th_ta_p,
+			  __nptl_initial_report_events, 0);
+    }
+  else
+    {
+      /* Copy the whole descriptor in once so we can access the several
+	 fields locally.  Excess copying in one go is much better than
+	 multiple ps_pdread calls.  */
+      err = DB_GET_STRUCT (copy, th->th_ta_p, th->th_unique, pthread);
+      if (err != TD_OK)
+	return err;
+
+      err = DB_GET_FIELD_ADDRESS (tls, th->th_ta_p, th->th_unique,
+				  pthread, specific, 0);
+      if (err != TD_OK)
+	return err;
+
+      err = DB_GET_FIELD_LOCAL (schedpolicy, th->th_ta_p, copy, pthread,
+				schedpolicy, 0);
+      if (err != TD_OK)
+	return err;
+      err = DB_GET_FIELD_LOCAL (schedprio, th->th_ta_p, copy, pthread,
+				schedparam_sched_priority, 0);
+      if (err != TD_OK)
+	return err;
+      err = DB_GET_FIELD_LOCAL (tid, th->th_ta_p, copy, pthread, tid, 0);
+      if (err != TD_OK)
+	return err;
+      err = DB_GET_FIELD_LOCAL (cancelhandling, th->th_ta_p, copy, pthread,
+				cancelhandling, 0);
+      if (err != TD_OK)
+	return err;
+      err = DB_GET_FIELD_LOCAL (report_events, th->th_ta_p, copy, pthread,
+				report_events, 0);
+    }
   if (err != TD_OK)
     return err;
 
@@ -86,9 +100,10 @@ td_thr_get_info (const td_thrhandle_t *th, td_thrinfo_t *infop)
   infop->ti_lid = tid == 0 ? ps_getpid (th->th_ta_p->ph) : (uintptr_t) tid;
   infop->ti_traceme = report_events != 0;
 
-  err = DB_GET_FIELD_LOCAL (infop->ti_startfunc, th->th_ta_p, copy, pthread,
-			    start_routine, 0);
-  if (err == TD_OK)
+  if (copy != NULL)
+    err = DB_GET_FIELD_LOCAL (infop->ti_startfunc, th->th_ta_p, copy, pthread,
+			      start_routine, 0);
+  if (copy != NULL && err == TD_OK)
     {
       uint32_t idx;
       for (idx = 0; idx < TD_EVENTSIZE; ++idx)
diff --git a/libpthread/nptl_db/td_thr_getfpregs.c b/libpthread/nptl_db/td_thr_getfpregs.c
index ff4b5997d..4f4742a3e 100644
--- a/libpthread/nptl_db/td_thr_getfpregs.c
+++ b/libpthread/nptl_db/td_thr_getfpregs.c
@@ -1,5 +1,5 @@
 /* Get a thread's floating-point register set.
-   Copyright (C) 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2001, 2002, 2003, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -28,6 +28,11 @@ td_thr_getfpregs (const td_thrhandle_t *th, prfpregset_t *regset)
 
   LOG ("td_thr_getfpregs");
 
+  if (th->th_unique == 0)
+    /* Special case for the main thread before initialization.  */
+    return ps_lgetfpregs (th->th_ta_p->ph, ps_getpid (th->th_ta_p->ph),
+			  regset) != PS_OK ? TD_ERR : TD_OK;
+
   /* We have to get the state and the PID for this thread.  */
   err = DB_GET_FIELD (cancelhandling, th->th_ta_p, th->th_unique, pthread,
 		      cancelhandling, 0);
diff --git a/libpthread/nptl_db/td_thr_getgregs.c b/libpthread/nptl_db/td_thr_getgregs.c
index 497941b75..d5f0f61a8 100644
--- a/libpthread/nptl_db/td_thr_getgregs.c
+++ b/libpthread/nptl_db/td_thr_getgregs.c
@@ -1,5 +1,5 @@
 /* Get a thread's general register set.
-   Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2000, 2001, 2002, 2003, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -28,6 +28,11 @@ td_thr_getgregs (const td_thrhandle_t *th, prgregset_t regset)
 
   LOG ("td_thr_getgregs");
 
+  if (th->th_unique == 0)
+    /* Special case for the main thread before initialization.  */
+    return ps_lgetregs (th->th_ta_p->ph, ps_getpid (th->th_ta_p->ph),
+			regset) != PS_OK ? TD_ERR : TD_OK;
+
   /* We have to get the state and the PID for this thread.  */
   err = DB_GET_FIELD (cancelhandling, th->th_ta_p, th->th_unique, pthread,
 		      cancelhandling, 0);
diff --git a/libpthread/nptl_db/td_thr_setfpregs.c b/libpthread/nptl_db/td_thr_setfpregs.c
index 3c4e8edc3..3154953fe 100644
--- a/libpthread/nptl_db/td_thr_setfpregs.c
+++ b/libpthread/nptl_db/td_thr_setfpregs.c
@@ -1,5 +1,5 @@
 /* Set a thread's floating-point register set.
-   Copyright (C) 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2001, 2002, 2003, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -28,6 +28,11 @@ td_thr_setfpregs (const td_thrhandle_t *th, const prfpregset_t *fpregs)
 
   LOG ("td_thr_setfpregs");
 
+  if (th->th_unique == 0)
+    /* Special case for the main thread before initialization.  */
+    return ps_lsetfpregs (th->th_ta_p->ph, ps_getpid (th->th_ta_p->ph),
+			  fpregs) != PS_OK ? TD_ERR : TD_OK;
+
   /* We have to get the state and the PID for this thread.  */
   err = DB_GET_FIELD (cancelhandling, th->th_ta_p, th->th_unique, pthread,
 		      cancelhandling, 0);
diff --git a/libpthread/nptl_db/td_thr_setgregs.c b/libpthread/nptl_db/td_thr_setgregs.c
index 83d2cd9a5..5945dea90 100644
--- a/libpthread/nptl_db/td_thr_setgregs.c
+++ b/libpthread/nptl_db/td_thr_setgregs.c
@@ -1,5 +1,5 @@
 /* Set a thread's general register set.
-   Copyright (C) 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1999, 2001, 2002, 2003, 2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -28,6 +28,11 @@ td_thr_setgregs (const td_thrhandle_t *th, prgregset_t gregs)
 
   LOG ("td_thr_setgregs");
 
+  if (th->th_unique == 0)
+    /* Special case for the main thread before initialization.  */
+    return ps_lsetregs (th->th_ta_p->ph, ps_getpid (th->th_ta_p->ph),
+			gregs) != PS_OK ? TD_ERR : TD_OK;
+
   /* We have to get the state and the PID for this thread.  */
   err = DB_GET_FIELD (cancelhandling, th->th_ta_p, th->th_unique, pthread,
 		      cancelhandling, 0);
diff --git a/libpthread/nptl_db/td_thr_tlsbase.c b/libpthread/nptl_db/td_thr_tlsbase.c
index f7d4c2966..9f98bd9ae 100644
--- a/libpthread/nptl_db/td_thr_tlsbase.c
+++ b/libpthread/nptl_db/td_thr_tlsbase.c
@@ -1,5 +1,5 @@
 /* Locate TLS data for a thread.
-   Copyright (C) 2003, 2006 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2006, 2007 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
@@ -29,8 +29,29 @@ td_thr_tlsbase (const td_thrhandle_t *th,
   if (modid < 1)
     return TD_NOTLS;
 
+  psaddr_t pd = th->th_unique;
+  if (pd == 0)
+    {
+      /* This is the fake handle for the main thread before libpthread
+	 initialization.  We are using 0 for its th_unique because we can't
+	 trust that its thread register has been initialized.  But we need
+	 a real pointer to have any TLS access work.  In case of dlopen'd
+	 libpthread, initialization might not be for quite some time.  So
+	 try looking up the thread register now.  Worst case, it's nonzero
+	 uninitialized garbage and we get bogus results for TLS access
+	 attempted too early.  Tough.  */
+
+      td_thrhandle_t main_th;
+      err = __td_ta_lookup_th_unique (th->th_ta_p, ps_getpid (th->th_ta_p->ph),
+				      &main_th);
+      if (err == 0)
+	pd = main_th.th_unique;
+      if (pd == 0)
+	return TD_TLSDEFER;
+    }
+
   /* Get the DTV pointer from the thread descriptor.  */
-  err = DB_GET_FIELD (dtv, th->th_ta_p, th->th_unique, pthread, dtvp, 0);
+  err = DB_GET_FIELD (dtv, th->th_ta_p, pd, pthread, dtvp, 0);
   if (err != TD_OK)
     return err;
 
diff --git a/libpthread/nptl_db/td_thr_validate.c b/libpthread/nptl_db/td_thr_validate.c
index 49c30c103..1b96b5156 100644
--- a/libpthread/nptl_db/td_thr_validate.c
+++ b/libpthread/nptl_db/td_thr_validate.c
@@ -1,5 +1,5 @@
 /* Validate a thread handle.
-   Copyright (C) 1999, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1999,2001,2002,2003,2004,2007 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@redhat.com>, 1999.
 
@@ -74,16 +74,10 @@ td_thr_validate (const td_thrhandle_t *th)
       if (err == TD_OK)
 	err = check_thread_list (th, list, &uninit);
 
-      if (err == TD_NOTHR && uninit)
-	{
-	  /* __pthread_initialize_minimal has not run yet.
-	     But the main thread still has a valid ID.  */
-	  td_thrhandle_t main_th;
-	  err = td_ta_map_lwp2thr (th->th_ta_p,
-				   ps_getpid (th->th_ta_p->ph), &main_th);
-	  if (err == TD_OK && th->th_unique != main_th.th_unique)
-	    err = TD_NOTHR;
-	}
+      if (err == TD_NOTHR && uninit && th->th_unique == 0)
+	/* __pthread_initialize_minimal has not run yet.
+	   There is only the special case thread handle.  */
+	err = TD_OK;
     }
 
   return err;
diff --git a/libpthread/nptl_db/thread_dbP.h b/libpthread/nptl_db/thread_dbP.h
index 24623ef79..b8399f758 100644
--- a/libpthread/nptl_db/thread_dbP.h
+++ b/libpthread/nptl_db/thread_dbP.h
@@ -1,5 +1,5 @@
 /* Private header for thread debug library
-   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 2003, 2004, 2007 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
@@ -254,4 +254,7 @@ extern td_err_e _td_store_value_local (td_thragent_t *ta,
 extern td_err_e _td_check_sizeof (td_thragent_t *ta, uint32_t *sizep,
 				  int sizep_name) attribute_hidden;
 
+extern td_err_e __td_ta_lookup_th_unique (const td_thragent_t *ta,
+					  lwpid_t lwpid, td_thrhandle_t *th);
+
 #endif /* thread_dbP.h */