3 files changed, 170 insertions, 0 deletions
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index c50edad..16b756c 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2016-05-24  Pedro Alves  <palves@redhat.com>
+
+	PR gdb/19828
+	* gdb.threads/clone-attach-detach.c: New file.
+	* gdb.threads/clone-attach-detach.exp: New file.
+
 2016-05-24  Francis Ricci  <francisjricci@gmail.com>  (tiny patch)
 
 	* gdb.base/annota-input-while-running.exp: Fix syntax error.
diff --git a/gdb/testsuite/gdb.threads/clone-attach-detach.c b/gdb/testsuite/gdb.threads/clone-attach-detach.c
new file mode 100644
index 0000000..daa8f1f
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/clone-attach-detach.c
@@ -0,0 +1,66 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2016 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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
+#define _GNU_SOURCE
+#include <sched.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#define STACK_SIZE 0x1000
+
+int clone_pid;
+
+static int
+clone_fn (void *unused)
+{
+  /* Wait for alarm.  */
+  while (1)
+    sleep (1);
+  return 0;
+}
+
+int
+main (int argc, char **argv)
+{
+  unsigned char *stack;
+  int res;
+
+  alarm (300);
+
+  stack = malloc (STACK_SIZE);
+  assert (stack != NULL);
+
+#define CLONE_FLAGS (CLONE_THREAD | CLONE_SIGHAND | CLONE_VM)
+
+#ifdef __ia64__
+  clone_pid = __clone2 (clone_fn, stack, STACK_SIZE, CLONE_FLAGS, NULL);
+#else
+  clone_pid = clone (clone_fn, stack + STACK_SIZE, CLONE_FLAGS, NULL);
+#endif
+
+  assert (clone_pid > 0);
+
+  /* Wait for alarm.  */
+  while (1)
+    sleep (1);
+
+  return 0;
+}
diff --git a/gdb/testsuite/gdb.threads/clone-attach-detach.exp b/gdb/testsuite/gdb.threads/clone-attach-detach.exp
new file mode 100644
index 0000000..42e9914
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/clone-attach-detach.exp
@@ -0,0 +1,98 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2016 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# Test attach / detach from a process that uses raw clone.  We use raw
+# clone as proxy for when libthread_db is not available.
+
+# This only works on targets with the Linux kernel.
+if ![istarget *-*-linux*] {
+    return
+}
+
+if {![can_spawn_for_attach]} {
+    return 0
+}
+
+standard_testfile
+
+if [prepare_for_testing "failed to prepare" $testfile $srcfile {debug}] {
+    return -1
+}
+
+clean_restart ${binfile}
+
+set test_spawn_id [spawn_wait_for_attach $binfile]
+set testpid [spawn_id_get_pid $test_spawn_id]
+
+# Native/gdbserver.
+set thread_re "(LWP $decimal|Thread )"
+
+# Try attach / detach a few times, in case GDB ends up with stale
+# state after detaching.
+
+set attempts 3
+for {set attempt 1} {$attempt <= $attempts} {incr attempt} {
+    with_test_prefix "fg attach $attempt" {
+
+	gdb_test "attach $testpid" \
+	    "Attaching to program.*process $testpid.*" \
+	    "attach"
+
+	gdb_test "info threads" \
+	    "1.*${thread_re}.*\r\n.*2.*${thread_re}.*" \
+	    "info threads shows two LWPs"
+
+	gdb_test "detach" "Detaching from .*, process $testpid"
+    }
+}
+
+# Same, but use async/background attach.
+
+# If debugging with target remote, check whether the all-stop variant
+# of the RSP is being used.  If so, we can't run the background tests.
+if {[target_info exists gdb_protocol]
+    && ([target_info gdb_protocol] == "remote"
+	|| [target_info gdb_protocol] == "extended-remote")} {
+
+    set test "maint show target-non-stop"
+    gdb_test_multiple "maint show target-non-stop" $test {
+	-re "(is|currently) on.*$gdb_prompt $" {
+	}
+	-re "(is|currently) off.*$gdb_prompt $" {
+	    unsupported "bg attach: can't issue info threads while target is running"
+	    return 0
+	}
+    }
+}
+
+set attempts 3
+for {set attempt 1} {$attempt <= $attempts} {incr attempt} {
+    with_test_prefix "bg attach $attempt" {
+
+	gdb_test "attach $testpid &" \
+	    "Attaching to program.*process $testpid.*" \
+	    "attach"
+
+	gdb_test "info threads" \
+	    "1.*${thread_re}.*\\(running\\)\r\n.*2.*${thread_re}.*\\(running\\)" \
+	    "info threads shows two LWPs"
+
+	gdb_test "detach" "Detaching from .*, process $testpid"
+    }
+}
+
+kill_wait_spawned_process $test_spawn_id