qtest: Fix crash if SIGABRT during qtest_init()

If an assertion fails during qtest_init() the SIGABRT handler is
invoked.  This is the correct behavior since we need to kill the QEMU
process to avoid leaking it when the test dies.

The global_qtest pointer used by the SIGABRT handler is currently only
assigned after qtest_init() returns.  This results in a segfault if an
assertion failure occurs during qtest_init().

Move global_qtest assignment inside qtest_init().  Not pretty but let's
face it - the signal handler depends on global state.

Reported-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Marcel Apfelbaum <marcel.a@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/libqtest.c b/tests/libqtest.c
index 2b90e4a76e..b03b57a3db 100644
--- a/tests/libqtest.c
+++ b/tests/libqtest.c
@@ -120,7 +120,7 @@ QTestState *qtest_init(const char *extra_args)
     qemu_binary = getenv("QTEST_QEMU_BINARY");
     g_assert(qemu_binary != NULL);
 
-    s = g_malloc(sizeof(*s));
+    global_qtest = s = g_malloc(sizeof(*s));
 
     socket_path = g_strdup_printf("/tmp/qtest-%d.sock", getpid());
     qmp_socket_path = g_strdup_printf("/tmp/qtest-%d.qmp", getpid());
@@ -181,6 +181,7 @@ QTestState *qtest_init(const char *extra_args)
 void qtest_quit(QTestState *s)
 {
     sigaction(SIGABRT, &s->sigact_old, NULL);
+    global_qtest = NULL;
 
     kill_qemu(s);
     close(s->fd);