Hi Yuriy, OK, that all makes sense.
Here's the full trace with symbols: #0 0xb7769be0 in __kernel_vsyscall () (gdb) bt full #0 0xb7769be0 in __kernel_vsyscall () No symbol table info available. #1 0xb7444126 in kill () from /lib/i386-linux-gnu/i686/cmov/libc.so.6 No symbol table info available. #2 0x80133265 in crash.lto_priv.251 (sig=6) at ../src/core/main.c:190 sa = {__sigaction_handler = {sa_handler = 0x0, sa_sigaction = 0x0}, sa_mask = {__val = {0 <repeats 32 times>}}, sa_flags = 0, sa_restorer = 0x0} __func__ = "crash" __PRETTY_FUNCTION__ = "crash" #3 <signal handler called> No symbol table info available. #4 0xb7769be0 in __kernel_vsyscall () No symbol table info available. #5 0xb7443e36 in raise () from /lib/i386-linux-gnu/i686/cmov/libc.so.6 No symbol table info available. #6 0xb7445407 in abort () from /lib/i386-linux-gnu/i686/cmov/libc.so.6 No symbol table info available. #7 0x8017e06f in log_assert_failed (text=text@entry=0x801ded2d "b", file=file@entry=0x801e505c "../src/basic/path-util.c", line=line@entry=390, func=0x801fcfb4 <__PRETTY_FUNCTION__.8936> "path_compare") at ../src/basic/log.c:788 No locals. #8 0x8017f167 in path_compare (a=<optimized out>, b=0x0) at ../src/basic/path-util.c:390 d = <optimized out> __PRETTY_FUNCTION__ = "path_compare" #9 0x8017f308 in path_equal () at ../src/basic/path-util.c:433 No locals. #10 0x8010c661 in device_setup_unit (m=m@entry=0x81f377f8, dev=dev@entry=0x0, path=path@entry=0x82005aa8 "/dev/sde1", main=false) at ../src/core/device.c:324 e = 0x82006760 "dev-sde1.device" sysfs = <optimized out> u = 0x8200bad0 delete = <optimized out> r = <optimized out> __PRETTY_FUNCTION__ = "device_setup_unit" __func__ = "device_setup_unit" #11 0x8010fbf3 in device_found_node (m=m@entry=0x81f377f8, node=0x82005aa8 "/dev/sde1", add=add@entry=true, found=DEVICE_FOUND_MOUNT, now=true) at ../src/core/device.c:830 dev = 0x0 st = {st_dev = 53688455864, __pad1 = 0, __st_ino = 7, st_mode = 2149927392, st_nlink = 2149927392, st_uid = 2149927392, st_gid = 3219526928, st_rdev = 13827762142796840961, __pad2 = 5223, st_size = -5234089312160518424, st_blksize = -1218656384, st_blocks = -5234089864091353088, st_atim = {tv_sec = 224449792, tv_nsec = -2113906008}, st_mtim = { tv_sec = -2113877109, tv_nsec = -2146119061}, st_ctim = {tv_sec = -2145039904, tv_nsec = -2113876944}, st_ino = 13827762864351346689} __PRETTY_FUNCTION__ = "device_found_node" __func__ = "device_found_node" #12 0x8010fe6c in mount_load_proc_self_mountinfo.lto_priv.530 (m=0x81f377f8, set_flags=true) at ../src/core/mount.c:1537 device = 0x8200ccc8 "/dev/sde1" k = <optimized out> path = 0x8200cc30 "/media/usb1" options = 0x8200cd40 "rw,nodev,noexec,noatime,nodiratime,sync,fmask=0022,dmask=0022,codepage=437,iocharset=utf8,shortname=mixed,errors=remount-ro" fstype = 0x8200ccb8 "vfat" d = 0x82005aa8 "/dev/sde1" p = 0x8200eee8 "/media/usb1" fs = 0x8200cb98 t = 0x81fe0e90 i = 0x81fee988 r = 0 __PRETTY_FUNCTION__ = "mount_load_proc_self_mountinfo" __func__ = "mount_load_proc_self_mountinfo" #13 0x8011776c in mount_dispatch_io (source=0x81f3f848, fd=9, revents=1, userdata=0x81f377f8) at ../src/core/mount.c:1669 around = 0x0 gone = 0x0 m = 0x81f377f8 what = 0xbfe615b0 "" i = {idx = 0, next_key = 0x8018481d <internal_hashmap_iterate+13>} u = <optimized out> r = <optimized out> __PRETTY_FUNCTION__ = "mount_dispatch_io" __func__ = "mount_dispatch_io" #14 0x8011f650 in source_dispatch.lto_priv.983 (s=0x81f3f848) at ../src/libsystemd/sd-event/sd-event.c:2273 r = <optimized out> __PRETTY_FUNCTION__ = "source_dispatch" __func__ = "source_dispatch" #15 0x801a83ac in sd_event_dispatch (e=0x81f37b20) at ../src/libsystemd/sd-event/sd-event.c:2625 p = <optimized out> r = <optimized out> #16 sd_event_run (timeout=<optimized out>, e=0x81f37b20) at ../src/libsystemd/sd-event/sd-event.c:2684 r = <optimized out> #17 manager_loop (m=0x81f377f8) at ../src/core/manager.c:2051 wait_usec = <optimized out> r = <optimized out> rl = {interval = 1000000, begin = 141532531177, burst = 50000, num = 1} __PRETTY_FUNCTION__ = "manager_loop" __func__ = "manager_loop" #18 0x800f7626 in main (argc=1, argv=0xbfe620c4) at ../src/core/main.c:1827 m = 0x81f377f8 r = <optimized out> retval = 1 before_startup = <optimized out> after_startup = <optimized out> timespan = "\000\000\000\000\002\216:V\000\000\000\000\000\320x\267R\231w\267\302x4\267\376\245v\267\000\320x\267\034\231w\267\000\320x\267\302x4\267<\325x\267$\031w\267\000}A\267xyA\267\001\000\000" fds = 0x0 reexecute = false shutdown_verb = 0x0 initrd_timestamp = <optimized out> userspace_timestamp = {realtime = 1458797412056566, monotonic = 67928234} kernel_timestamp = {realtime = <optimized out>, monotonic = 0} security_start_timestamp = {realtime = 1458797412107590, monotonic = 67979258} security_finish_timestamp = {realtime = 1458797412125352, monotonic = 67997020} systemd = "systemd" skip_setup = <optimized out> j = <optimized out> loaded_policy = false arm_reboot_watchdog = false queue_default_job = <optimized out> empty_etc = <optimized out> switch_root_dir = 0x0 switch_root_init = 0x0 saved_rlimit_nofile = {rlim_cur = 1024, rlim_max = 4096} error_message = 0x0 __func__ = "main" __PRETTY_FUNCTION__ = "main" I hope that helps, Kingsley -- Time is the fire in which we all burn.