Bug#698097: gnome-shell: Still hangs, but 10 minutes or so after startup this time

[BlueSloth]

It hung again.  It's hung 2 out of 3 times so far.  I looked at the
clock this time, so I know it was 10 minutes after startup.

And I got a backtrace this time (the "$1 = 30118832" at the end is from
doing "call gjs_dumpstack ()" in gdb):

Thread 5 (Thread 0x7f524dcd6700 (LWP 4010)):
#0  0x00007f5258a00e33 in poll () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f5258f21624 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f5258f21a82 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f525a4b7a86 in ?? () from /usr/lib/x86_64-linux-gnu/libgio-2.0.so.0
#4  0x00007f5258f43f45 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f5258cc1b50 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#6  0x00007f5258a0ba7d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 4 (Thread 0x7f524d2b1700 (LWP 4011)):
#0  0x00007f5258a00e33 in poll () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f5258f21624 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f5258f21a82 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f524d2b9efb in ?? () from /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
#4  0x00007f5258f43f45 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f5258cc1b50 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#6  0x00007f5258a0ba7d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 3 (Thread 0x7f5247fff700 (LWP 4013)):
#0  0x00007f5258cc62d4 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
#1  0x00007f5260d92c90 in PR_WaitCondVar () from /usr/lib/x86_64-linux-gnu/libnspr4.so
#2  0x00007f5261473a47 in ?? () from /usr/lib/libmozjs185.so.1.0
#3  0x00007f5260d983b3 in ?? () from /usr/lib/x86_64-linux-gnu/libnspr4.so
#4  0x00007f5258cc1b50 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#5  0x00007f5258a0ba7d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#6  0x0000000000000000 in ?? ()

Thread 2 (Thread 0x7f523690d700 (LWP 4460)):
#0  0x00007f5258a00e33 in poll () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x00007f5258f21624 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f5258f21744 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f5258f21791 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f5258f43f45 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f5258cc1b50 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#6  0x00007f5258a0ba7d in clone () from /lib/x86_64-linux-gnu/libc.so.6
#7  0x0000000000000000 in ?? ()

Thread 1 (Thread 0x7f526294a9a0 (LWP 4008)):
#0  0x00007f5258cc62d4 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
#1  0x00007f5260d92c90 in PR_WaitCondVar () from /usr/lib/x86_64-linux-gnu/libnspr4.so
#2  0x00007f526146dcd2 in ?? () from /usr/lib/libmozjs185.so.1.0
#3  0x00007f5261473c89 in ?? () from /usr/lib/libmozjs185.so.1.0
#4  0x00007f52614746f5 in ?? () from /usr/lib/libmozjs185.so.1.0
#5  0x00007f52625108ad in on_gc_timeout (data=<optimized out>) at shell-global.c:1642
#6  0x00007f5258f21eeb in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#7  0x00007f5258f21355 in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#8  0x00007f5258f21688 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#9  0x00007f5258f21a82 in g_main_loop_run () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#10 0x00007f5261bb4f27 in meta_run () from /usr/lib/libmutter.so.0
#11 0x0000000000401e77 in main (argc=1, argv=0x7fff9d1b9618) at main.c:334
$1 = 30118832