[PATCH xwayland] xwayland: Unconditionally initialize lists in init_tablet_manager_seat()

[Peter Hutterer]

On Thu, May 04, 2017 at 06:04:31PM -0400, Lyude wrote:
> In the event that xwayland gets launched on a wayland compositor that
> doesn't yet have support for wp_tablet_manager, we end up skipping the
> initialization of the lists. This is wrong, because regardless of
> whether or not a tablet is present we still attempt to traverse these
> lists later in xwl_set_cursor(), expecting that if the lists are empty
> from no tablet manager that we simply won't execute any loop iterations.
> 
> (EE)
> (EE) Backtrace:
> (EE) 0: Xwayland (OsSigHandler+0x3b) [0x4982f9]
> (EE) 1: /lib64/libpthread.so.0 (__restore_rt+0x0) [0x7f73722545bf]
> (EE) 2: Xwayland (xwl_set_cursor+0x9f) [0x429974]
> (EE) 3: Xwayland (miPointerUpdateSprite+0x261) [0x4fe1ca]
> (EE) 4: Xwayland (mieqProcessInputEvents+0x239) [0x4f8d33]
> (EE) 5: Xwayland (ProcessInputEvents+0x9) [0x4282f0]
> (EE) 6: Xwayland (Dispatch+0x42) [0x43e2d4]
> (EE) 7: Xwayland (dix_main+0x5c9) [0x44c6dc]
> (EE) 8: Xwayland (main+0x28) [0x61c523]
> (EE) 9: /lib64/libc.so.6 (__libc_start_main+0xf1) [0x7f7371e9d401]
> (EE) 10: Xwayland (_start+0x2a) [0x4208fa]
> (EE) 11: ? (?+0x2a) [0x2a]
> (EE)
> (EE) Segmentation fault at address 0x28
> (EE)
> Fatal server error:
> (EE) Caught signal 11 (Segmentation fault). Server aborting
> (EE)
> 
> Reproduced when trying to run upstream xwayland under fedora 25's weston
> package.
> 
> Signed-off-by: Lyude <lyude at redhat.com>
> Cc: Carlos Garnacho <carlosg at gnome.org>
> Cc: Peter Hutterer <peter.hutterer at who-t.net>
> ---

oops. Pushed, thanks

remote: Updating patchwork state for https://patchwork.freedesktop.org/project/Xorg/list/
remote: I: patch #154673 updated using rev a06bb73053d9df56d9070ce325a43af3a3c7a6a2.
remote: I: 1 patch(es) updated to state Accepted.
To git+ssh://git.freedesktop.org/git/xorg/xserver
   5f83b951a..a06bb7305  master -> master

Cheers,
  Peter


>  hw/xwayland/xwayland-input.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/hw/xwayland/xwayland-input.c b/hw/xwayland/xwayland-input.c
> index bb667c4..557aac8 100644
> --- a/hw/xwayland/xwayland-input.c
> +++ b/hw/xwayland/xwayland-input.c
> @@ -2194,6 +2194,10 @@ static void
>  init_tablet_manager_seat(struct xwl_screen *xwl_screen,
>                           struct xwl_seat *xwl_seat)
>  {
> +    xorg_list_init(&xwl_seat->tablets);
> +    xorg_list_init(&xwl_seat->tablet_tools);
> +    xorg_list_init(&xwl_seat->tablet_pads);
> +
>      if (!xwl_screen->tablet_manager)
>          return;
>  
> @@ -2201,10 +2205,6 @@ init_tablet_manager_seat(struct xwl_screen *xwl_screen,
>          zwp_tablet_manager_v2_get_tablet_seat(xwl_screen->tablet_manager,
>                                                xwl_seat->seat);
>  
> -    xorg_list_init(&xwl_seat->tablets);
> -    xorg_list_init(&xwl_seat->tablet_tools);
> -    xorg_list_init(&xwl_seat->tablet_pads);
> -
>      zwp_tablet_seat_v2_add_listener(xwl_seat->tablet_seat, &tablet_seat_listener, xwl_seat);
>  }
>  
> -- 
> 2.9.3
>