Deadlock changing background 4.16 (debian)

This is triggered by Variety but the deadlock is in xfdesktop (or glib, I will file this there as well)

I traced it down to xfce_backdrop_load_image_files() setting a monitor on the directory the image is in, which takes a lock on the monitor. if there's a inotify event causing a monitor release at the same time the monitor thread grabs the locks as well, deadlocking. I think in this case it's on .xsession-errors being written to?

I hit this quite often because Variety changing the background every few minutes, so every few days the xfdesktop process will lockup.

Backtraces Main thread:

gdb) bt
#0  syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1  0x00007faaab03725c in g_mutex_lock_slowpath (mutex=mutex@entry=0x7faaab3113e8 <g.inotify_lock_lock>) at ../../../glib/gthread-posix.c:1493
#2  0x00007faaab037d32 in g_mutex_lock (mutex=mutex@entry=0x7faaab3113e8 <g.inotify_lock_lock>) at ../../../glib/gthread-posix.c:1517
#3  0x00007faaab274ac4 in _ih_startup () at ../../../gio/inotify/inotify-helper.c:74
#4  0x00007faaab2744b0 in g_inotify_file_monitor_start
    (local_monitor=<optimized out>, dirname=0x564029b29890 "/home/USERNAME/.config/variety/Downloaded/Unsplash", basename=0x0, filename=0x0, source=0x56402df58690)
    at ../../../gio/inotify/ginotifyfilemonitor.c:61
#5  0x00007faaab269f58 in g_local_file_monitor_new_for_path (pathname=0x56402df725e0 "/home/USERNAME/.config/variety/Downloaded/Unsplash", is_directory=1, flags=G_FILE_MONITOR_NONE, error=0x0)
    at ../../../gio/glocalfilemonitor.c:887
#6  0x0000564026070e56 in xfce_backdrop_load_image_files (backdrop=0x5640268bf990 [XfceBackdrop]) at xfce-backdrop.c:536

Monitor thread:

#0  syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1  0x00007faaab03725c in g_mutex_lock_slowpath (mutex=mutex@entry=0x7faaab3113e8 <g.inotify_lock_lock>) at ../../../glib/gthread-posix.c:1493
#2  0x00007faaab037d32 in g_mutex_lock (mutex=mutex@entry=0x7faaab3113e8 <g.inotify_lock_lock>) at ../../../glib/gthread-posix.c:1517
#3  0x00007faaab274bb9 in _ih_sub_cancel (sub=0x56402ae31750) at ../../../gio/inotify/inotify-helper.c:121
#4  0x00007faaab27445a in g_inotify_file_monitor_cancel (monitor=0x7faa9c2221f0 [GInotifyFileMonitor]) at ../../../gio/inotify/ginotifyfilemonitor.c:75
#5  0x00007faaab19ce69 in g_file_monitor_cancel (monitor=0x7faa9c2221f0 [GInotifyFileMonitor]) at ../../../gio/gfilemonitor.c:241
#6  0x00007faaab19ceec in g_file_monitor_dispose (object=0x7faa9c2221f0 [GInotifyFileMonitor]) at ../../../gio/gfilemonitor.c:123
#7  0x00007faaab0e27e1 in g_object_unref (_object=<optimized out>) at ../../../gobject/gobject.c:3636
#8  g_object_unref (_object=0x7faa9c2221f0) at ../../../gobject/gobject.c:3553
#9  0x00007faaab2695f8 in g_file_monitor_source_handle_event
    (fms=0x564029abf8d0, event_type=<optimized out>, child=0x7faaa4015980 ".xsession-errors", rename_to=rename_to@entry=0x0, other=<optimized out>, other@entry=0x0, event_time=<optimized out>)
    at ../../../gio/glocalfilemonitor.c:455
#10 0x00007faaab2748ae in ih_event_callback (event=0x7faaa4002ac0, sub=0x56402ae31750, file_event=<optimized out>) at ../../../gio/inotify/inotify-helper.c:206
#11 0x00007faaab27509c in ip_event_dispatch (dir_list=dir_list@entry=0x56402df36680 = {...}, file_list=0x0, event=event@entry=0x7faaa4002ac0) at ../../../gio/inotify/inotify-path.c:493
#12 0x00007faaab27528e in ip_event_dispatch (event=0x7faaa4002ac0, file_list=<optimized out>, dir_list=0x56402df36680 = {...}) at ../../../gio/inotify/inotify-path.c:448
#13 ip_event_callback (event=0x7faaa4002ac0) at ../../../gio/inotify/inotify-path.c:548
#14 ip_event_callback (event=0x7faaa4002ac0) at ../../../gio/inotify/inotify-path.c:530
#15 0x00007faaab275d11 in ik_source_dispatch (source=0x5640269dc420, func=0x7faaab2751d0 <ip_event_callback>, user_data=<optimized out>) at ../../../gio/inotify/inotify-kernel.c:327
#16 0x00007faaaafe3e94 in g_main_dispatch (context=0x5640268acae0) at ../../../glib/gmain.c:3417
#17 g_main_context_dispatch (context=0x5640268acae0) at ../../../glib/gmain.c:4135
#18 0x00007faaaafe4238 in g_main_context_iterate (context=context@entry=0x5640268acae0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at ../../../glib/gmain.c:4211
#19 0x00007faaaafe42ef in g_main_context_iteration (context=0x5640268acae0, may_block=may_block@entry=1) at ../../../glib/gmain.c:4276
#20 0x00007faaaafe4341 in glib_worker_main (data=<optimized out>) at ../../../glib/gmain.c:6178
#21 0x00007faaab00e59d in g_thread_proxy (data=0x564026887e40) at ../../../glib/gthread.c:827
#22 0x00007faaaaf74d80 in start_thread (arg=0x7faaa95a3640) at pthread_create.c:481
#23 0x00007faaaae8e76f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95