Locking the screen crashes after !3958

Affected version

Bug summary

After screen locking a core dump follows.

Relevant logs, screenshots, screencasts etc.

Stack trace:

#0  0x00007fc39faa53f4 n/a (libc.so.6 + 0x963f4)
#1  0x00007fc39fa4c120 raise (libc.so.6 + 0x3d120)
#2  0x000056319f93e14d dump_gjs_stack_on_signal_handler (gnome-shell + 0x314d)
#3  0x00007fc39fa4c1d0 n/a (libc.so.6 + 0x3d1d0)
#4  0x00007fc39faa53f4 n/a (libc.so.6 + 0x963f4)
#5  0x00007fc39fa4c120 raise (libc.so.6 + 0x3d120)
#6  0x00007fc39fa334c3 abort (libc.so.6 + 0x244c3)
#7  0x00007fc3a030011b n/a (libglib-2.0.so.0 + 0x1e11b)
#8  0x00007fc3a036c8b9 g_assertion_message_expr (libglib-2.0.so.0 + 0x8a8b9)
#9  0x00007fc39fdb7d20 meta_kms_impl_device_hold_fd (libmutter-15.so.0 + 0x1b7d20)
#10 0x00007fc39fdbda3a meta_kms_update_realize (libmutter-15.so.0 + 0x1bda3a)
#11 0x00007fc39fdd5398 dispatch_task_func (libmutter-15.so.0 + 0x1d5398)
#12 0x00007fc3a033f459 n/a (libglib-2.0.so.0 + 0x5d459)
#13 0x00007fc3a03a20d7 n/a (libglib-2.0.so.0 + 0xc00d7)
#14 0x00007fc3a0340187 g_main_loop_run (libglib-2.0.so.0 + 0x5e187)
#15 0x00007fc39fdda0c8 meta_thread_impl_run (libmutter-15.so.0 + 0x1da0c8)
#16 0x00007fc3a0372f26 n/a (libglib-2.0.so.0 + 0x90f26)
#17 0x00007fc39faa339d n/a (libc.so.6 + 0x9439d)
#18 0x00007fc39fb2849c n/a (libc.so.6 + 0x11949c)

Cc: @daenzer