From e912742c1e26ef853064ddf672d990e1db254492 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Fri, 21 Oct 2016 10:11:45 +0200
Subject: [PATCH xserver v2] xwayland: Activate and enable touch devices

On some random condition, a touch event may trigger a crash in Xwayland
in GetTouchEvents().

The (simplified) backtrace goes as follow:

 (gdb) bt
 #0  GetTouchEvents() at getevents.c:1892
 #1  QueueTouchEvents() at getevents.c:1866
 #2  xwl_touch_send_event() at xwayland-input.c:652
 #5  wl_closure_invoke() from libwayland-client.so.0
 #6  dispatch_event() from libwayland-client.so.0
 #7  wl_display_dispatch_queue_pending() from libwayland-client.so.0
 #8  xwl_read_events() at xwayland.c:483
 #9  ospoll_wait() at ospoll.c:412
 #10 WaitForSomething() at WaitFor.c:222
 #11 Dispatch() at dispatch.c:412
 #12 dix_main() at main.c:287
 #13 __libc_start_main() at libc-start.c:289
 #14 _start ()

The crash occurs when trying to access the sprite associated with the
touch device, which appears to be NULL. Reason being the device itself
is more a keyboard device than a touch device.

Moreover, it appears the device is neither enabled nor activated
(inited=0, enabled=0) which doesn't seem right, but matches the code in
init_touch() from xwayland-input.c which would enable the device if it
was previously existing and otherwise would create the device but not
activate it.

Make sure we do activate and enable touch devices just like we do for
other input devices such as keyboard and pointer.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 hw/xwayland/xwayland-input.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
index 1991076..7ec3b1a 100644
--- a/hw/xwayland/xwayland-input.c
+++ b/hw/xwayland/xwayland-input.c
@@ -1059,12 +1059,13 @@ init_touch(struct xwl_seat *xwl_seat)
     wl_touch_add_listener(xwl_seat->wl_touch,
                           &touch_listener, xwl_seat);
 
-    if (xwl_seat->touch)
-        EnableDevice(xwl_seat->touch, TRUE);
-    else {
+    if (xwl_seat->touch == NULL) {
         xwl_seat->touch =
             add_device(xwl_seat, "xwayland-touch", xwl_touch_proc);
+        ActivateDevice(xwl_seat->touch, TRUE);
     }
+    EnableDevice(xwl_seat->touch, TRUE);
+
 }
 
 static void
-- 
2.9.3