this is darktable 1.6.3 reporting a segfault:

#0  0x00007fbbc4bcdee9 in waitpid () from /lib/x86_64-linux-gnu/libpthread.so.0
#1  0x00007fbbc4e639c0 in ?? () from /usr/bin/../lib/darktable/libdarktable.so
#2  <signal handler called>
#3  0x00007fbbc4ea175d in dt_mipmap_cache_allocate () from /usr/bin/../lib/darktable/libdarktable.so
#4  0x00007fbbc4e57daa in dt_cache_read_get () from /usr/bin/../lib/darktable/libdarktable.so
#5  0x00007fbbc4ea24d9 in ?? () from /usr/bin/../lib/darktable/libdarktable.so
#6  0x00007fbbc4e66219 in dt_init () from /usr/bin/../lib/darktable/libdarktable.so
#7  0x00000000004007e0 in main ()

Thread 6 (Thread 0x7fbbb83f3700 (LWP 6810)):
#0  0x00007fbbc4bca414 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007fbbc4ebec46 in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#2  0x00007fbbc4bc6182 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3  0x00007fbbc48f347d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.

Thread 5 (Thread 0x7fbbb7bf2700 (LWP 6811)):
#0  0x00007fbbc4bca414 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007fbbc4ebec46 in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#2  0x00007fbbc4bc6182 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3  0x00007fbbc48f347d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.

Thread 4 (Thread 0x7fbbb73f1700 (LWP 6812)):
#0  0x00007fbbc48b9f3d in nanosleep () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#1  0x00007fbbc48b9dd4 in sleep () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#2  0x00007fbbc4ebdd9a in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#3  0x00007fbbc4bc6182 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#4  0x00007fbbc48f347d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.

Thread 3 (Thread 0x7fbbaffff700 (LWP 6813)):
#0  0x00007fbbc4bca414 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007fbbc4ebe10e in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#2  0x00007fbbc4bc6182 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3  0x00007fbbc48f347d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.

Thread 2 (Thread 0x7fbbb6bf0700 (LWP 6814)):
#0  0x00007fbbc4bca414 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007fbbc4ebe10e in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#2  0x00007fbbc4bc6182 in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#3  0x00007fbbc48f347d in clone () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.

Thread 1 (Thread 0x7fbbc54cfa40 (LWP 6809)):
#0  0x00007fbbc4bcdee9 in waitpid () from /lib/x86_64-linux-gnu/libpthread.so.0
No symbol table info available.
#1  0x00007fbbc4e639c0 in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#2  <signal handler called>
No symbol table info available.
#3  0x00007fbbc4ea175d in dt_mipmap_cache_allocate () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#4  0x00007fbbc4e57daa in dt_cache_read_get () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#5  0x00007fbbc4ea24d9 in ?? () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#6  0x00007fbbc4e66219 in dt_init () from /usr/bin/../lib/darktable/libdarktable.so
No symbol table info available.
#7  0x00000000004007e0 in main ()
No symbol table info available.