Blame SOURCES/gdb-6.5-bz216711-clone-is-outermost.patch

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From FEDORA_PATCHES Mon Sep 17 00:00:00 2001
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From: Jan Kratochvil <jan.kratochvil@redhat.com>
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Date: Fri, 27 Oct 2017 21:07:50 +0200
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Subject: gdb-6.5-bz216711-clone-is-outermost.patch
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;; Fix bogus 0x0 unwind of the thread's topmost function clone(3) (BZ 216711).
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;;=fedora
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https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=216711
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FIXME: This workaround should be dropped and
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glibc/sysdeps/unix/sysv/linux/x86_64/clone.S should get CFI for the child
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instead.
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2006-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>
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	* gdb/amd64-linux-tdep.c (linux_clone_code): New variable.
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	(LINUX_CLONE_LEN): New definition.
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	(amd64_linux_clone_running, amd64_linux_outermost_frame): New function.
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	(amd64_linux_init_abi): Initialize `outermost_frame_p'.
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	* gdb/i386-tdep.c (i386_gdbarch_init): Likewise.
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	* gdb/i386-tdep.h (gdbarch_tdep): Add `outermost_frame_p' member.
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	* gdb/amd64-tdep.c (amd64_frame_this_id): Call `outermost_frame_p'.
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2006-12-17  Jan Kratochvil  <jan.kratochvil@redhat.com>
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	* gdb.threads/bt-clone-stop.exp, gdb.threads/bt-clone-stop.c:
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	New file.
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2007-10-16  Jan Kratochvil  <jan.kratochvil@redhat.com>
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	Port to GDB-6.7.
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diff --git a/gdb/amd64-linux-tdep.c b/gdb/amd64-linux-tdep.c
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--- a/gdb/amd64-linux-tdep.c
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+++ b/gdb/amd64-linux-tdep.c
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@@ -291,6 +291,80 @@ amd64_linux_register_reggroup_p (struct gdbarch *gdbarch, int regnum,
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 /* Set the program counter for process PTID to PC.  */
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+/* Detect the outermost frame; during unwind of
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+   	#5  0x000000305cec68c3 in clone () from /lib64/tls/libc.so.6
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+   avoid the additional bogus frame
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+   	#6  0x0000000000000000 in ??
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+   We compare if the `linux_clone_code' block is _before_ unwound PC.  */
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+
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+static const unsigned char linux_clone_code[] =
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+{
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+/* libc/sysdeps/unix/sysv/linux/x86_64/clone.S */
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+/* #ifdef RESET_PID */
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+/* ... */
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+/* 	mov	$SYS_ify(getpid), %eax */
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+/* 0xb8, 0x27, 0x00, 0x00, 0x00 */
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+/* OR */
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+/* 	mov	$SYS_ify(getpid), %rax */
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+/* 0x48, 0xc7, 0xc0, 0x27, 0x00, 0x00, 0x00 */
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+/* so just: */
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+  0x27, 0x00, 0x00, 0x00,
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+/* 	syscall */
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+  0x0f, 0x05,
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+/* 	movl	%eax, %fs:PID */
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+  0x64, 0x89, 0x04, 0x25, 0x94, 0x00, 0x00, 0x00,
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+/* 	movl	%eax, %fs:TID */
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+  0x64, 0x89, 0x04, 0x25, 0x90, 0x00, 0x00, 0x00,
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+/* #endif */
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+/* 	|* Set up arguments for the function call.  *| */
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+/* 	popq	%rax		|* Function to call.  *| */
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+  0x58,
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+/* 	popq	%rdi		|* Argument.  *| */
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+  0x5f,
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+/* 	call	*%rax$   */
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+  0xff, 0xd0
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+};
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+
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+#define LINUX_CLONE_LEN (sizeof linux_clone_code)
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+
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+static int
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+amd64_linux_clone_running (struct frame_info *this_frame)
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+{
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+  CORE_ADDR pc = get_frame_pc (this_frame);
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+  unsigned char buf[LINUX_CLONE_LEN];
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+
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+  if (!safe_frame_unwind_memory (this_frame, pc - LINUX_CLONE_LEN, buf,
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+				 LINUX_CLONE_LEN))
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+    return 0;
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+
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+  if (memcmp (buf, linux_clone_code, LINUX_CLONE_LEN) != 0)
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+    return 0;
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+
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+  return 1;
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+}
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+
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+static int
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+amd64_linux_outermost_frame (struct frame_info *this_frame)
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+{
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+  CORE_ADDR pc = get_frame_pc (this_frame);
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+  const char *name;
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+
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+  find_pc_partial_function (pc, &name, NULL, NULL);
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+
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+  /* If we have NAME, we can optimize the search.
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+     `clone' NAME still needs to have the code checked as its name may be
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+     present in the user code.
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+     `__clone' NAME should not be present in the user code but in the initial
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+     parts of the `__clone' implementation the unwind still makes sense.
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+     More detailed unwinding decision would be too much sensitive to possible
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+     subtle changes in specific glibc revisions.  */
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+  if (name == NULL || strcmp (name, "clone") == 0
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+      || strcmp ("__clone", name) == 0)
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+    return (amd64_linux_clone_running (this_frame) != 0);
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+
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+  return 0;
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+}
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+
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 static void
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 amd64_linux_write_pc (struct regcache *regcache, CORE_ADDR pc)
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 {
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@@ -1808,6 +1882,8 @@ amd64_linux_init_abi_common(struct gdbarch_info info, struct gdbarch *gdbarch)
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   tdep->xsave_xcr0_offset = I386_LINUX_XSAVE_XCR0_OFFSET;
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+  tdep->outermost_frame_p = amd64_linux_outermost_frame;
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+
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   /* Add the %orig_rax register used for syscall restarting.  */
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   set_gdbarch_write_pc (gdbarch, amd64_linux_write_pc);
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diff --git a/gdb/amd64-tdep.c b/gdb/amd64-tdep.c
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--- a/gdb/amd64-tdep.c
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+++ b/gdb/amd64-tdep.c
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@@ -2595,6 +2595,7 @@ amd64_frame_unwind_stop_reason (struct frame_info *this_frame,
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 {
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   struct amd64_frame_cache *cache =
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     amd64_frame_cache (this_frame, this_cache);
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+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
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   if (!cache->base_p)
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     return UNWIND_UNAVAILABLE;
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@@ -2603,6 +2604,10 @@ amd64_frame_unwind_stop_reason (struct frame_info *this_frame,
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   if (cache->base == 0)
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     return UNWIND_OUTERMOST;
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+  /* Detect OS dependent outermost frames; such as `clone'.  */
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+  if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame))
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+    return UNWIND_OUTERMOST;
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+
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   return UNWIND_NO_REASON;
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 }
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@@ -2737,6 +2742,7 @@ amd64_sigtramp_frame_this_id (struct frame_info *this_frame,
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 {
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   struct amd64_frame_cache *cache =
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     amd64_sigtramp_frame_cache (this_frame, this_cache);
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+  struct gdbarch_tdep *tdep = gdbarch_tdep (get_frame_arch (this_frame));
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   if (!cache->base_p)
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     (*this_id) = frame_id_build_unavailable_stack (get_frame_pc (this_frame));
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@@ -2745,6 +2751,11 @@ amd64_sigtramp_frame_this_id (struct frame_info *this_frame,
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       /* This marks the outermost frame.  */
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       return;
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     }
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+  else if (tdep->outermost_frame_p && tdep->outermost_frame_p (this_frame))
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+    {
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+      /* Detect OS dependent outermost frames; such as `clone'.  */
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+      return;
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+    }
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   else
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     (*this_id) = frame_id_build (cache->base + 16, get_frame_pc (this_frame));
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 }
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diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
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--- a/gdb/i386-tdep.c
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+++ b/gdb/i386-tdep.c
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@@ -8406,6 +8406,9 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
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   tdep->xsave_xcr0_offset = -1;
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+  /* Unwinding stops on i386 automatically.  */
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+  tdep->outermost_frame_p = NULL;
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+
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   tdep->record_regmap = i386_record_regmap;
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   set_gdbarch_type_align (gdbarch, i386_type_align);
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diff --git a/gdb/i386-tdep.h b/gdb/i386-tdep.h
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--- a/gdb/i386-tdep.h
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+++ b/gdb/i386-tdep.h
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@@ -251,6 +251,9 @@ struct gdbarch_tdep
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   /* Regsets. */
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   const struct regset *fpregset;
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+
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+  /* Detect OS dependent outermost frames; such as `clone'.  */
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+  int (*outermost_frame_p) (struct frame_info *this_frame);
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 };
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 /* Floating-point registers.  */
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diff --git a/gdb/testsuite/gdb.threads/bt-clone-stop.c b/gdb/testsuite/gdb.threads/bt-clone-stop.c
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new file mode 100644
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--- /dev/null
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+++ b/gdb/testsuite/gdb.threads/bt-clone-stop.c
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@@ -0,0 +1,39 @@
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+/* This testcase is part of GDB, the GNU debugger.
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+
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+   Copyright 2006 Free Software Foundation, Inc.
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+
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+   This program is free software; you can redistribute it and/or modify
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+   it under the terms of the GNU General Public License as published by
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+   the Free Software Foundation; either version 2 of the License, or
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+   (at your option) any later version.
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+
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+   This program is distributed in the hope that it will be useful,
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+   but WITHOUT ANY WARRANTY; without even the implied warranty of
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+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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+   GNU General Public License for more details.
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+ 
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+   You should have received a copy of the GNU General Public License
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+   along with this program; if not, write to the Free Software
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+   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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+   MA 02110-1301, USA.  */
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+
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+
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+#include <pthread.h>
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+#include <unistd.h>
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+#include <assert.h>
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+
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+
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+void *threader (void *arg)
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+{
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+	assert (0);
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+	return NULL;
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+}
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+
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+int main (void)
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+{
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+	pthread_t t1;
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+
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+	pthread_create (&t1, NULL, threader, (void *) NULL);
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+	for (;;)
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+		pause();
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+}
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diff --git a/gdb/testsuite/gdb.threads/bt-clone-stop.exp b/gdb/testsuite/gdb.threads/bt-clone-stop.exp
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new file mode 100644
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--- /dev/null
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+++ b/gdb/testsuite/gdb.threads/bt-clone-stop.exp
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@@ -0,0 +1,61 @@
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+# Copyright 2006 Free Software Foundation, Inc.
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+
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+# This program is free software; you can redistribute it and/or modify
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+# it under the terms of the GNU General Public License as published by
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+# the Free Software Foundation; either version 2 of the License, or
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+# (at your option) any later version.
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+# 
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+# This program is distributed in the hope that it will be useful,
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+# but WITHOUT ANY WARRANTY; without even the implied warranty of
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+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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+# GNU General Public License for more details.
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+# 
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+# You should have received a copy of the GNU General Public License
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+# along with this program; if not, write to the Free Software
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+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  
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+
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+# Backtraced `clone' must not have `PC == 0' as its previous frame.
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+
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+if $tracelevel then {
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+    strace $tracelevel
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+}
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+
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+set testfile bt-clone-stop
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+set srcfile ${testfile}.c
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+set binfile [standard_output_file ${testfile}]
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+if  { [gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
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+    untested "Couldn't compile test program"
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+    return -1
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+}
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+
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+# Get things started.
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+
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+gdb_exit
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+gdb_start
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+gdb_reinitialize_dir $srcdir/$subdir
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+gdb_load ${binfile}
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+
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+# threader: threader.c:8: threader: Assertion `0' failed.
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+# Program received signal SIGABRT, Aborted.
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+
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+gdb_test "run" \
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+     {Thread 2 "bt-clone-stop" received signal SIGABRT.*} \
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+     "run"
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+
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+# Former gdb unwind (the first function is `clone'):
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+# #5  0x0000003421ecd62d in ?? () from /lib64/libc.so.6
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+# #6  0x0000000000000000 in ?? ()
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+# (gdb)
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+# Tested `amd64_linux_outermost_frame' functionality should omit the line `#6'.
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+# 
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+# Two `-re' cases below must be in this order (1st is a subset of the 2nd one).
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+# Unhandled case below should not happen and it is fortunately handled by
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+# `amd64_linux_outermost_frame' as FAIL (and result `0x0 entry output invalid').
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+gdb_test_multiple "bt" "0x0 entry output invalid" {
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+    -re "in threader \\(.*\n#\[0-9\]* *0x0* in .*$gdb_prompt $" {
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+    	fail "0x0 entry found"
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+    }
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+    -re "in threader \\(.*$gdb_prompt $" {
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+    	pass "0x0 entry not found"
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+    }
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+}