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Reading symbols from /usr/bin/gnome-shell...(no debugging symbols found)...done.
[New LWP 2864]
[New LWP 2907]
[New LWP 2949]
[New LWP 2954]
[New LWP 2945]
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
Core was generated by `gnome-shell --mode=gdm'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0  center_pointer (backend=0x182b8d0 [MetaBackendX11]) at backends/meta-backend.c:106
106	backends/meta-backend.c: No such file or directory.
[Current thread is 1 (Thread 0x7f3436effa80 (LWP 2864))]
(gdb) backtrace full
#0  0x00007f3435983035 in center_pointer (backend=0x182b8d0 [MetaBackendX11]) at backends/meta-backend.c:106
        monitors = 0x0
        primary = 0x0
        n_monitors = 0
#1  0x00007f343598f246 in meta_backend_x11_post_init (backend=0x182b8d0 [MetaBackendX11]) at backends/x11/meta-backend-x11.c:499
        x11 = <optimized out>
        major = 2
        minor = 3
#2  0x00007f34359b6402 in meta_init () at core/main.c:358
        act = {__sigaction_handler = {sa_handler = 0x1, sa_sigaction = 0x1}, sa_mask = {__val = {0 <repeats 16 times>}}, sa_flags = 0, sa_restorer = 0x0}
        empty_mask = {__val = {0 <repeats 16 times>}}
#3  0x0000000000401ee2 in main ()
(gdb) info registers
rax            0x0	0
rbx            0x182b8d0	25344208
rcx            0x0	0
rdx            0x0	0
rsi            0x7ffe2e35f244	140729673708100
rdi            0x182b8d0	25344208
rbp            0x0	0x0
rsp            0x7ffe2e35f240	0x7ffe2e35f240
r8             0x0	0
r9             0x1	1
r10            0x2e0	736
r11            0x7f3430f88a30	139862136621616
r12            0x182b8b0	25344176
r13            0x182b840	25344064
r14            0x1828900	25331968
r15            0x0	0
rip            0x7f3435983035	0x7f3435983035 <center_pointer+85>
eflags         0x10246	[ PF ZF IF RF ]
cs             0x33	51
ss             0x2b	43
ds             0x0	0
es             0x0	0
fs             0x0	0
gs             0x0	0
(gdb) x/16i $pc
=> 0x7f3435983035 <center_pointer+85>:	mov    0x14(%rax),%edx
   0x7f3435983038 <center_pointer+88>:	mov    %edx,%ecx
   0x7f343598303a <center_pointer+90>:	shr    $0x1f,%ecx
   0x7f343598303d <center_pointer+93>:	add    %ecx,%edx
   0x7f343598303f <center_pointer+95>:	mov    0x10(%rax),%ecx
   0x7f3435983042 <center_pointer+98>:	sar    %edx
   0x7f3435983044 <center_pointer+100>:	add    0xc(%rax),%edx
   0x7f3435983047 <center_pointer+103>:	mov    %ecx,%esi
   0x7f3435983049 <center_pointer+105>:	shr    $0x1f,%esi
   0x7f343598304c <center_pointer+108>:	add    %ecx,%esi
   0x7f343598304e <center_pointer+110>:	mov    %esi,%ecx
   0x7f3435983050 <center_pointer+112>:	sar    %ecx
   0x7f3435983052 <center_pointer+114>:	add    0x8(%rax),%ecx
   0x7f3435983055 <center_pointer+117>:	mov    %ecx,%esi
   0x7f3435983057 <center_pointer+119>:	callq  0x7f3435982fd0 <meta_backend_warp_pointer>
   0x7f343598305c <center_pointer+124>:	mov    0x8(%rsp),%rax
(gdb) thread apply all backtrace

Thread 5 (Thread 0x7f3417fff700 (LWP 2945)):
#0  0x00007f3433dadaad in sendmsg () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f34347a58d3 in g_socket_send_message_with_timeout (socket=0x1c30670 [GSocket], address=address@entry=0x0, vectors=vectors@entry=0x7f3417ffe9b0, num_vectors=<optimized out>, 
    num_vectors@entry=1, messages=0x0, num_messages=<optimized out>, num_messages@entry=0, flags=0, timeout=0, cancellable=0x1c36b60 [GCancellable], error=0x7f3417ffe9a8) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gsocket.c:4342
#2  0x00007f34347a6057 in g_socket_send_message (socket=<optimized out>, address=address@entry=0x0, vectors=vectors@entry=0x7f3417ffe9b0, num_vectors=num_vectors@entry=1, messages=<optimized out>, num_messages=num_messages@entry=0, flags=0, cancellable=0x1c36b60 [GCancellable], error=0x7f3417ffe9a8) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gsocket.c:4251
#3  0x00007f3434810c58 in write_message_continue_writing (data=data@entry=0x1c3acd0) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gdbusprivate.c:1003
#4  0x00007f3434811030 in continue_writing (callback=0x7f34348114a0 <write_message_cb>, worker=0x7f3408003600, user_data=0x1c3acd0, data=0x1c3acd0) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gdbusprivate.c:1095
#5  0x00007f3434811030 in continue_writing (worker=0x7f3408003600) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gdbusprivate.c:1495
#6  0x00007f34348115ff in write_message_cb (source_object=<optimized out>, res=<optimized out>, user_data=0x7f3410005d60) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gdbusprivate.c:1313
#7  0x00007f34347b2b33 in g_task_return_now (task=0x7f3410003060 [GTask]) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gtask.c:1107
#8  0x00007f34347b2b69 in complete_in_idle_cb (task=0x7f3410003060) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gtask.c:1121
#9  0x00007f3434003fda in g_main_context_dispatch (context=0x1c34300) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3154
#10 0x00007f3434003fda in g_main_context_dispatch (context=context@entry=0x1c34300) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3769
#11 0x00007f3434004380 in g_main_context_iterate (context=0x1c34300, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3840
#12 0x00007f34340046a2 in g_main_loop_run (loop=0x1c36220) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:4034
#13 0x00007f343480f906 in gdbus_shared_thread_func (user_data=0x1c342d0) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./gio/gdbusprivate.c:246
#14 0x00007f343402ab45 in g_thread_proxy (data=0x1824540) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthread.c:780
#15 0x00007f3433da46fa in start_thread (arg=0x7f3417fff700) at pthread_create.c:333
#16 0x00007f3433adab5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 4 (Thread 0x7f3416dbd700 (LWP 2954)):
#0  0x00007f3433acee8d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f343400431c in g_main_context_iterate (priority=2147483647, n_fds=1, fds=0x7f340c0010c0, timeout=<optimized out>, context=0x1c40090) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:4135
#2  0x00007f343400431c in g_main_context_iterate (context=context@entry=0x1c40090, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3835
#3  0x00007f343400442c in g_main_context_iteration (context=0x1c40090, may_block=1) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3901
#4  0x00007f3416dc528d in  () at /usr/lib/x86_64-linux-gnu/gio/modules/libdconfsettings.so
#5  0x00007f343402ab45 in g_thread_proxy (data=0x1c3dad0) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthread.c:780
#6  0x00007f3433da46fa in start_thread (arg=0x7f3416dbd700) at pthread_create.c:333
---Type <return> to continue, or q <return> to quit---
#7  0x00007f3433adab5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 3 (Thread 0x7f34177fe700 (LWP 2949)):
#0  0x00007f3433ad4c19 in syscall () at ../sysdeps/unix/sysv/linux/x86_64/syscall.S:38
#1  0x00007f3434048cca in g_cond_wait_until (cond=cond@entry=0x1c33ca8, mutex=mutex@entry=0x1c33ca0, end_time=end_time@entry=15247419) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthread-posix.c:1444
#2  0x00007f3433fd8929 in g_async_queue_pop_intern_unlocked (queue=0x1c33ca0, wait=wait@entry=1, end_time=15247419) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gasyncqueue.c:422
#3  0x00007f3433fd8f88 in g_async_queue_timeout_pop_unlocked (queue=<optimized out>, timeout=timeout@entry=500000) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gasyncqueue.c:570
#4  0x00007f343402b4b6 in g_thread_pool_thread_proxy (pool=0x1c33c40) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthreadpool.c:262
#5  0x00007f343402b4b6 in g_thread_pool_thread_proxy (data=<optimized out>) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthreadpool.c:296
#6  0x00007f343402ab45 in g_thread_proxy (data=0x18248a0) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthread.c:780
#7  0x00007f3433da46fa in start_thread (arg=0x7f34177fe700) at pthread_create.c:333
#8  0x00007f3433adab5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 2 (Thread 0x7f341f77d700 (LWP 2907)):
#0  0x00007f3433acee8d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f343400431c in g_main_context_iterate (priority=2147483647, n_fds=1, fds=0x7f34180008e0, timeout=<optimized out>, context=0x18242c0) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:4135
#2  0x00007f343400431c in g_main_context_iterate (context=context@entry=0x18242c0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3835
#3  0x00007f343400442c in g_main_context_iteration (context=0x18242c0, may_block=may_block@entry=1) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:3901
#4  0x00007f3434004469 in glib_worker_main (data=<optimized out>) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gmain.c:5672
#5  0x00007f343402ab45 in g_thread_proxy (data=0x1824400) at /build/glib2.0-t9oPgV/glib2.0-2.48.0/./glib/gthread.c:780
#6  0x00007f3433da46fa in start_thread (arg=0x7f341f77d700) at pthread_create.c:333
#7  0x00007f3433adab5d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f3436effa80 (LWP 2864)):
#0  0x00007f3435983035 in center_pointer (backend=0x182b8d0 [MetaBackendX11]) at backends/meta-backend.c:106
#1  0x00007f343598f246 in meta_backend_x11_post_init (backend=0x182b8d0 [MetaBackendX11]) at backends/x11/meta-backend-x11.c:499
#2  0x00007f34359b6402 in meta_init () at core/main.c:358
#3  0x0000000000401ee2 in main ()