[packages/gdb.git] / gdb-6.5-bz216711-clone-is-outermost.patch

https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216711

FIXME: This workaround should be dropped and
glibc/sysdeps/unix/sysv/linux/x86_64/clone.S should get CFI for the child
instead.

2006-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb/amd64-linux-tdep.c (linux_clone_code): New variable.
	(LINUX_CLONE_LEN): New definition.
	(amd64_linux_clone_running, amd64_linux_outermost_frame): New function.
	(amd64_linux_init_abi): Initialize `outermost_frame_p'.
	* gdb/i386-tdep.c (i386_gdbarch_init): Likewise.
	* gdb/i386-tdep.h (gdbarch_tdep): Add `outermost_frame_p' member.
	* gdb/amd64-tdep.c (amd64_frame_this_id): Call `outermost_frame_p'.

2006-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.threads/bt-clone-stop.exp, gdb.threads/bt-clone-stop.c:
	New file.

2007-10-16  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Port to GDB-6.7.

Index: gdb-6.8.50.20090802/gdb/amd64-linux-tdep.c
===================================================================
--- gdb-6.8.50.20090802.orig/gdb/amd64-linux-tdep.c	2009-07-02 19:25:52.000000000 +0200
+++ gdb-6.8.50.20090802/gdb/amd64-linux-tdep.c	2009-08-03 15:50:08.000000000 +0200
@@ -238,6 +238,80 @@ amd64_linux_register_reggroup_p (struct 
 
 /* Set the program counter for process PTID to PC.  */
 
+/* Detect the outermost frame; during unwind of
+   	#5  0x000000305cec68c3 in clone () from /lib64/tls/libc.so.6
+   avoid the additional bogus frame
+   	#6  0x0000000000000000 in ??
+   We compare if the `linux_clone_code' block is _before_ unwound PC.  */
+
+static const unsigned char linux_clone_code[] =
+{
+/* libc/sysdeps/unix/sysv/linux/x86_64/clone.S */
+/* #ifdef RESET_PID */
+/* ... */
+/* 	mov	$SYS_ify(getpid), %eax */
+/* 0xb8, 0x27, 0x00, 0x00, 0x00 */
+/* OR */
+/* 	mov	$SYS_ify(getpid), %rax */
+/* 0x48, 0xc7, 0xc0, 0x27, 0x00, 0x00, 0x00 */
+/* so just: */
+  0x27, 0x00, 0x00, 0x00,
+/* 	syscall */
+  0x0f, 0x05,
+/* 	movl	%eax, %fs:PID */
+  0x64, 0x89, 0x04, 0x25, 0x94, 0x00, 0x00, 0x00,
+/* 	movl	%eax, %fs:TID */
+  0x64, 0x89, 0x04, 0x25, 0x90, 0x00, 0x00, 0x00,
+/* #endif */
+/* 	|* Set up arguments for the function call.  *| */
+/* 	popq	%rax		|* Function to call.  *| */
+  0x58,
+/* 	popq	%rdi		|* Argument.  *| */
+  0x5f,
+/* 	call	*%rax$   */
+  0xff, 0xd0
+};
+
+#define LINUX_CLONE_LEN (sizeof linux_clone_code)
+
+static int
+amd64_linux_clone_running (struct frame_info *this_frame)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  unsigned char buf[LINUX_CLONE_LEN];
+
+  if (!safe_frame_unwind_memory (this_frame, pc - LINUX_CLONE_LEN, buf,
+				 LINUX_CLONE_LEN))
+    return 0;
+
+  if (memcmp (buf, linux_clone_code, LINUX_CLONE_LEN) != 0)
+    return 0;
+
+  return 1;
+}
+
+static int
+amd64_linux_outermost_frame (struct frame_info *this_frame)
+{
+  CORE_ADDR pc = get_frame_pc (this_frame);
+  char *name;
+
+  find_pc_partial_function (pc, &name, NULL, NULL);
+
+  /* If we have NAME, we can optimize the search.
+     `clone' NAME still needs to have the code checked as its name may be
+     present in the user code.
+     `__clone' NAME should not be present in the user code but in the initial
+     parts of the `__clone' implementation the unwind still makes sense.
+     More detailed unwinding decision would be too much sensitive to possible
+     subtle changes in specific glibc revisions.  */
+  if (name == NULL || strcmp (name, "clone") == 0
+      || strcmp ("__clone", name) == 0)
+    return (amd64_linux_clone_running (this_frame) != 0);
+
+  return 0;
+}
+
 static void
 amd64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
 {
@@ -276,6 +350,8 @@ amd64_linux_init_abi (struct gdbarch_inf
   tdep->sc_reg_offset = amd64_linux_sc_reg_offset;
   tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset);
 
+  tdep->outermost_frame_p = amd64_linux_outermost_frame;
+
   /* GNU/Linux uses SVR4-style shared libraries.  */
   set_solib_svr4_fetch_link_map_offsets
     (gdbarch, svr4_lp64_fetch_link_map_offsets);
Index: gdb-6.8.50.20090802/gdb/amd64-tdep.c
===================================================================
--- gdb-6.8.50.20090802.orig/gdb/amd64-tdep.c	2009-07-02 19:25:52.000000000 +0200
+++ gdb-6.8.50.20090802/gdb/amd64-tdep.c	2009-08-03 15:50:08.000000000 +0200
@@ -1736,11 +1736,16 @@ amd64_frame_this_id (struct frame_info *
 {
   struct amd64_frame_cache *cache =
     amd64_frame_cache (this_frame, this_cache);
+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
 
   /* This marks the outermost frame.  */
   if (cache->base == 0)
     return;
 
+  /* Detect OS dependent outermost frames; such as `clone'.  */
+  if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame))
+    return;
+
   (*this_id) = frame_id_build (cache->base + 16, cache->pc);
 }
 
--- gdb-6.8.50.20090811/gdb/i386-tdep.c.orig	2009-08-10 05:02:39.000000000 +0200
+++ gdb-6.8.50.20090811/gdb/i386-tdep.c	2009-08-11 16:33:51.000000000 +0200
@@ -5432,6 +5432,9 @@ i386_gdbarch_init (struct gdbarch_info i
   tdep->sc_pc_offset = -1;
   tdep->sc_sp_offset = -1;
 
+  /* Unwinding stops on i386 automatically.  */
+  tdep->outermost_frame_p = NULL;
+
   tdep->record_regmap = i386_record_regmap;
 
   /* The format used for `long double' on almost all i386 targets is
--- gdb-6.8.50.20090811/gdb/i386-tdep.h.orig	2009-08-10 05:02:39.000000000 +0200
+++ gdb-6.8.50.20090811/gdb/i386-tdep.h	2009-08-11 16:34:08.000000000 +0200
@@ -120,6 +120,9 @@ struct gdbarch_tdep
   int (*i386_sysenter_record) (struct regcache *regcache);
   /* Parse syscall args.  */
   int (*i386_syscall_record) (struct regcache *regcache);
+
+  /* Detect OS dependent outermost frames; such as `clone'.  */
+  int (*outermost_frame_p) (struct frame_info *this_frame);
 };
 
 /* Floating-point registers.  */
Index: gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.c	2009-08-03 15:50:08.000000000 +0200
@@ -0,0 +1,39 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2006 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+ 
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+   MA 02110-1301, USA.  */
+
+
+#include <pthread.h>
+#include <unistd.h>
+#include <assert.h>
+
+
+void *threader (void *arg)
+{
+	assert (0);
+	return NULL;
+}
+
+int main (void)
+{
+	pthread_t t1;
+
+	pthread_create (&t1, NULL, threader, (void *) NULL);
+	for (;;)
+		pause();
+}
Index: gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.exp
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.exp	2009-08-03 15:50:08.000000000 +0200
@@ -0,0 +1,61 @@
+# Copyright 2006 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
+
+# Backtraced `clone' must not have `PC == 0' as its previous frame.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set testfile bt-clone-stop
+set srcfile ${testfile}.c
+set binfile ${objdir}/${subdir}/${testfile}
+if  { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested "Couldn't compile test program"
+    return -1
+}
+
+# Get things started.
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+# threader: threader.c:8: threader: Assertion `0' failed.
+# Program received signal SIGABRT, Aborted.
+
+gdb_test "run" \
+     "Program received signal SIGABRT.*" \
+     "run"
+
+# Former gdb unwind (the first function is `clone'):
+# #5  0x0000003421ecd62d in ?? () from /lib64/libc.so.6
+# #6  0x0000000000000000 in ?? ()
+# (gdb)
+# Tested `amd64_linux_outermost_frame' functionality should omit the line `#6'.
+# 
+# Two `-re' cases below must be in this order (1st is a subset of the 2nd one).
+# Unhandled case below should not happen and it is fortunately handled by
+# `amd64_linux_outermost_frame' as FAIL (and result `0x0 entry output invalid').
+gdb_test_multiple "bt" "0x0 entry output invalid" {
+    -re "in threader \\(.*\n#\[0-9\]* *0x0* in .*$gdb_prompt $" {
+    	fail "0x0 entry found"
+    }
+    -re "in threader \\(.*$gdb_prompt $" {
+    	pass "0x0 entry not found"
+    }
+}
Commit	Line	Data
3a58abaf AM	1	https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216711
	2
	3	FIXME: This workaround should be dropped and
	4	glibc/sysdeps/unix/sysv/linux/x86_64/clone.S should get CFI for the child
	5	instead.
	6
	7	2006-12-17 Jan Kratochvil <jan.kratochvil@redhat.com>
	8
	9	* gdb/amd64-linux-tdep.c (linux_clone_code): New variable.
	10	(LINUX_CLONE_LEN): New definition.
	11	(amd64_linux_clone_running, amd64_linux_outermost_frame): New function.
	12	(amd64_linux_init_abi): Initialize `outermost_frame_p'.
	13	* gdb/i386-tdep.c (i386_gdbarch_init): Likewise.
	14	* gdb/i386-tdep.h (gdbarch_tdep): Add `outermost_frame_p' member.
	15	* gdb/amd64-tdep.c (amd64_frame_this_id): Call `outermost_frame_p'.
	16
	17	2006-12-17 Jan Kratochvil <jan.kratochvil@redhat.com>
	18
	19	* gdb.threads/bt-clone-stop.exp, gdb.threads/bt-clone-stop.c:
	20	New file.
	21
	22	2007-10-16 Jan Kratochvil <jan.kratochvil@redhat.com>
	23
	24	Port to GDB-6.7.
	25
7566401a	26	Index: gdb-6.8.50.20090802/gdb/amd64-linux-tdep.c
3a58abaf	27	===================================================================
7566401a ER	28	--- gdb-6.8.50.20090802.orig/gdb/amd64-linux-tdep.c 2009-07-02 19:25:52.000000000 +0200
	29	+++ gdb-6.8.50.20090802/gdb/amd64-linux-tdep.c 2009-08-03 15:50:08.000000000 +0200
	30	@@ -238,6 +238,80 @@ amd64_linux_register_reggroup_p (struct
3a58abaf AM	31
	32	/* Set the program counter for process PTID to PC. */
	33
	34	+/* Detect the outermost frame; during unwind of
	35	+ #5 0x000000305cec68c3 in clone () from /lib64/tls/libc.so.6
	36	+ avoid the additional bogus frame
	37	+ #6 0x0000000000000000 in ??
	38	+ We compare if the `linux_clone_code' block is _before_ unwound PC. */
	39	+
	40	+static const unsigned char linux_clone_code[] =
	41	+{
	42	+/* libc/sysdeps/unix/sysv/linux/x86_64/clone.S */
	43	+/* #ifdef RESET_PID */
	44	+/* ... */
	45	+/* mov $SYS_ify(getpid), %eax */
	46	+/* 0xb8, 0x27, 0x00, 0x00, 0x00 */
	47	+/* OR */
	48	+/* mov $SYS_ify(getpid), %rax */
	49	+/* 0x48, 0xc7, 0xc0, 0x27, 0x00, 0x00, 0x00 */
	50	+/* so just: */
	51	+ 0x27, 0x00, 0x00, 0x00,
	52	+/* syscall */
	53	+ 0x0f, 0x05,
	54	+/* movl %eax, %fs:PID */
	55	+ 0x64, 0x89, 0x04, 0x25, 0x94, 0x00, 0x00, 0x00,
	56	+/* movl %eax, %fs:TID */
	57	+ 0x64, 0x89, 0x04, 0x25, 0x90, 0x00, 0x00, 0x00,
	58	+/* #endif */
	59	+/* \|* Set up arguments for the function call. \| /
	60	+/* popq %rax \|* Function to call. \| /
	61	+ 0x58,
	62	+/* popq %rdi \|* Argument. \| /
	63	+ 0x5f,
	64	+/* call %rax$ /
	65	+ 0xff, 0xd0
	66	+};
	67	+
	68	+#define LINUX_CLONE_LEN (sizeof linux_clone_code)
	69	+
	70	+static int
	71	+amd64_linux_clone_running (struct frame_info *this_frame)
	72	+{
	73	+ CORE_ADDR pc = get_frame_pc (this_frame);
	74	+ unsigned char buf[LINUX_CLONE_LEN];
	75	+
	76	+ if (!safe_frame_unwind_memory (this_frame, pc - LINUX_CLONE_LEN, buf,
	77	+ LINUX_CLONE_LEN))
	78	+ return 0;
	79	+
	80	+ if (memcmp (buf, linux_clone_code, LINUX_CLONE_LEN) != 0)
	81	+ return 0;
	82	+
	83	+ return 1;
	84	+}
	85	+
	86	+static int
	87	+amd64_linux_outermost_frame (struct frame_info *this_frame)
	88	+{
	89	+ CORE_ADDR pc = get_frame_pc (this_frame);
	90	+ char *name;
	91	+
	92	+ find_pc_partial_function (pc, &name, NULL, NULL);
	93	+
	94	+ /* If we have NAME, we can optimize the search.
95	+ `clone' NAME still needs to have the code checked as its name may be
96	+ present in the user code.
97	+ `__clone' NAME should not be present in the user code but in the initial
98	+ parts of the `__clone' implementation the unwind still makes sense.
99	+ More detailed unwinding decision would be too much sensitive to possible
100	+ subtle changes in specific glibc revisions. */
101	+ if (name == NULL \|\| strcmp (name, "clone") == 0
102	+ \|\| strcmp ("__clone", name) == 0)
103	+ return (amd64_linux_clone_running (this_frame) != 0);
104	+
105	+ return 0;
106	+}
107	+
108	static void
109	amd64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
110	{
7566401a	111	@@ -276,6 +350,8 @@ amd64_linux_init_abi (struct gdbarch_inf
3a58abaf AM	112	tdep->sc_reg_offset = amd64_linux_sc_reg_offset;
	113	tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset);
	114
	115	+ tdep->outermost_frame_p = amd64_linux_outermost_frame;
	116	+
	117	/* GNU/Linux uses SVR4-style shared libraries. */
	118	set_solib_svr4_fetch_link_map_offsets
	119	(gdbarch, svr4_lp64_fetch_link_map_offsets);
7566401a	120	Index: gdb-6.8.50.20090802/gdb/amd64-tdep.c
3a58abaf	121	===================================================================
7566401a ER	122	--- gdb-6.8.50.20090802.orig/gdb/amd64-tdep.c 2009-07-02 19:25:52.000000000 +0200
	123	+++ gdb-6.8.50.20090802/gdb/amd64-tdep.c 2009-08-03 15:50:08.000000000 +0200
	124	@@ -1736,11 +1736,16 @@ amd64_frame_this_id (struct frame_info *
3a58abaf AM	125	{
	126	struct amd64_frame_cache *cache =
	127	amd64_frame_cache (this_frame, this_cache);
	128	+ struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
	129
	130	/* This marks the outermost frame. */
	131	if (cache->base == 0)
	132	return;
	133
	134	+ /* Detect OS dependent outermost frames; such as `clone'. */
	135	+ if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame))
	136	+ return;
	137	+
	138	(*this_id) = frame_id_build (cache->base + 16, cache->pc);
	139	}
	140
7566401a ER	141	--- gdb-6.8.50.20090811/gdb/i386-tdep.c.orig 2009-08-10 05:02:39.000000000 +0200
	142	+++ gdb-6.8.50.20090811/gdb/i386-tdep.c 2009-08-11 16:33:51.000000000 +0200
	143	@@ -5432,6 +5432,9 @@ i386_gdbarch_init (struct gdbarch_info i
3a58abaf AM	144	tdep->sc_pc_offset = -1;
	145	tdep->sc_sp_offset = -1;
	146
	147	+ /* Unwinding stops on i386 automatically. */
	148	+ tdep->outermost_frame_p = NULL;
	149	+
7566401a ER	150	tdep->record_regmap = i386_record_regmap;
7566401a ER	151
3a58abaf	152	/* The format used for `long double' on almost all i386 targets is
7566401a ER	153	--- gdb-6.8.50.20090811/gdb/i386-tdep.h.orig 2009-08-10 05:02:39.000000000 +0200
	154	+++ gdb-6.8.50.20090811/gdb/i386-tdep.h 2009-08-11 16:34:08.000000000 +0200
	155	@@ -120,6 +120,9 @@ struct gdbarch_tdep
	156	int (i386_sysenter_record) (struct regcache regcache);
	157	/* Parse syscall args. */
	158	int (i386_syscall_record) (struct regcache regcache);
3a58abaf AM	159	+
	160	+ /* Detect OS dependent outermost frames; such as `clone'. */
	161	+ int (outermost_frame_p) (struct frame_info this_frame);
	162	};
	163
	164	/* Floating-point registers. */
7566401a	165	Index: gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.c
3a58abaf AM	166	===================================================================
3a58abaf AM	167	--- /dev/null 1970-01-01 00:00:00.000000000 +0000
7566401a	168	+++ gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.c 2009-08-03 15:50:08.000000000 +0200
3a58abaf AM	169	@@ -0,0 +1,39 @@
	170	+/* This testcase is part of GDB, the GNU debugger.
	171	+
	172	+ Copyright 2006 Free Software Foundation, Inc.
	173	+
	174	+ This program is free software; you can redistribute it and/or modify
	175	+ it under the terms of the GNU General Public License as published by
	176	+ the Free Software Foundation; either version 2 of the License, or
	177	+ (at your option) any later version.
	178	+
	179	+ This program is distributed in the hope that it will be useful,
	180	+ but WITHOUT ANY WARRANTY; without even the implied warranty of
	181	+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	182	+ GNU General Public License for more details.
	183	+
	184	+ You should have received a copy of the GNU General Public License
	185	+ along with this program; if not, write to the Free Software
	186	+ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
	187	+ MA 02110-1301, USA. */
	188	+
	189	+
	190	+#include <pthread.h>
	191	+#include <unistd.h>
	192	+#include <assert.h>
	193	+
	194	+
	195	+void threader (void arg)
	196	+{
	197	+ assert (0);
	198	+ return NULL;
	199	+}
	200	+
	201	+int main (void)
	202	+{
	203	+ pthread_t t1;
	204	+
	205	+ pthread_create (&t1, NULL, threader, (void *) NULL);
	206	+ for (;;)
	207	+ pause();
	208	+}
7566401a	209	Index: gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.exp
3a58abaf AM	210	===================================================================
3a58abaf AM	211	--- /dev/null 1970-01-01 00:00:00.000000000 +0000
7566401a	212	+++ gdb-6.8.50.20090802/gdb/testsuite/gdb.threads/bt-clone-stop.exp 2009-08-03 15:50:08.000000000 +0200
3a58abaf AM	213	@@ -0,0 +1,61 @@
	214	+# Copyright 2006 Free Software Foundation, Inc.
	215	+
	216	+# This program is free software; you can redistribute it and/or modify
	217	+# it under the terms of the GNU General Public License as published by
	218	+# the Free Software Foundation; either version 2 of the License, or
	219	+# (at your option) any later version.
	220	+#
	221	+# This program is distributed in the hope that it will be useful,
	222	+# but WITHOUT ANY WARRANTY; without even the implied warranty of
	223	+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	224	+# GNU General Public License for more details.
	225	+#
	226	+# You should have received a copy of the GNU General Public License
	227	+# along with this program; if not, write to the Free Software
	228	+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	229	+
	230	+# Backtraced `clone' must not have `PC == 0' as its previous frame.
	231	+
	232	+if $tracelevel then {
	233	+ strace $tracelevel
	234	+}
	235	+
	236	+set testfile bt-clone-stop
	237	+set srcfile ${testfile}.c
	238	+set binfile ${objdir}/${subdir}/${testfile}
	239	+if { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
	240	+ untested "Couldn't compile test program"
	241	+ return -1
	242	+}
	243	+
	244	+# Get things started.
	245	+
	246	+gdb_exit
	247	+gdb_start
	248	+gdb_reinitialize_dir $srcdir/$subdir
	249	+gdb_load ${binfile}
	250	+
	251	+# threader: threader.c:8: threader: Assertion `0' failed.
	252	+# Program received signal SIGABRT, Aborted.
	253	+
	254	+gdb_test "run" \
	255	+ "Program received signal SIGABRT.*" \
	256	+ "run"
	257	+
	258	+# Former gdb unwind (the first function is `clone'):
	259	+# #5 0x0000003421ecd62d in ?? () from /lib64/libc.so.6
	260	+# #6 0x0000000000000000 in ?? ()
	261	+# (gdb)
	262	+# Tested `amd64_linux_outermost_frame' functionality should omit the line `#6'.
	263	+#
	264	+# Two `-re' cases below must be in this order (1st is a subset of the 2nd one).
	265	+# Unhandled case below should not happen and it is fortunately handled by
	266	+# `amd64_linux_outermost_frame' as FAIL (and result `0x0 entry output invalid').
	267	+gdb_test_multiple "bt" "0x0 entry output invalid" {
	268	+ -re "in threader \\(.\n#\[0-9\] 0x0 in .*$gdb_prompt $" {
	269	+ fail "0x0 entry found"
	270	+ }
	271	+ -re "in threader \\(.*$gdb_prompt $" {
	272	+ pass "0x0 entry not found"
	273	+ }
	274	+}