Compositor crashes when switching tty

[adlo]

On Fri, 2019-05-31 at 01:22 +0100, adlo wrote:
> On Thu, 2019-05-30 at 13:39 +0300, Pekka Paalanen wrote:
> > 
> > Hi,
> > 
> > as always, look at the very first problem reported. Other problems
> > may be fallout from the first one, so fix the first one, and
> > repeat.
> > 
> > It is quite easy to corrupt a list based on struct wl_list, which
> > will then result in more errors all over the place.
> > 
> 
> The first problem is this:
> 
> ==13998== Invalid write of size 8
> ==13998==    at 0x4884ADB: wl_list_remove (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x48A2585: weston_view_set_output (in
> /usr/lib64/libweston-6.so.0.0.0)
> ==13998==    by 0x48A41AD: weston_view_unmap (in
> /usr/lib64/libweston-
> 6.so.0.0.0)
> ==13998==    by 0x48A5587: weston_view_destroy (in
> /usr/lib64/libweston-6.so.0.0.0)
> ==13998==    by 0x48A5664: weston_surface_destroy (in
> /usr/lib64/libweston-6.so.0.0.0)
> ==13998==    by 0x4880927: ??? (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4884A7F: ??? (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4884FC3: ??? (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4880AA1: wl_client_destroy (in
> /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4880EDD: wl_display_flush_clients (in
> /usr/lib64/libwayland-server.so.0.1.0)
> ==13998==    by 0x4880F17: wl_display_run (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x403A57: main (main-wayland.c:625)
> ==13998==  Address 0x9fcda10 is 96 bytes inside a block of size 120
> free'd
> ==13998==    at 0x4839A0C: free (vg_replace_malloc.c:540)
> ==13998==    by 0x48DD073: ??? (in /usr/lib64/libweston-desktop-
> 6.so.0.0.0)
> ==13998==    by 0x48D8E53: ??? (in /usr/lib64/libweston-desktop-
> 6.so.0.0.0)
> ==13998==    by 0x4880927: ??? (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4880993: wl_resource_destroy (in
> /usr/lib64/libwayland-server.so.0.1.0)
> ==13998==    by 0x5984B27: ffi_call_unix64 (in
> /usr/lib64/libffi.so.6.0.2)
> ==13998==    by 0x5984338: ffi_call (in /usr/lib64/libffi.so.6.0.2)
> ==13998==    by 0x48841B6: ??? (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4880D31: ??? (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x4882369: wl_event_loop_dispatch (in
> /usr/lib64/libwayland-server.so.0.1.0)
> ==13998==    by 0x4880F24: wl_display_run (in /usr/lib64/libwayland-
> server.so.0.1.0)
> ==13998==    by 0x403A57: main (main-wayland.c:625)
> 
> However, this doesn't seem to call back into my compositor's code at
> any point. I see a call to weston_surface_destroy (), which suggests
> a
> surface was destroyed. However, if a surface was destroyed, I would
> expect to see a call to surface_removed () in src/shell.c. How do I
> interpret this?
> 

How do I debug something that isn't even part of my code? It goes
straight from main to wl_display_run to library code without calling
any of my callbacks.

Regards

adlo