Additional backtrace with more detail. Each bt I take (I've done about 10) shows that we're emitting a power_supply-device-added, is the kernel spamming us with events?

(gdb) attach 318
Attaching to process 318
Reading symbols from /sbin/upstart-udev-bridge...Reading symbols from /usr/lib/debug/sbin/upstart-udev-bridge...done.
done.
Reading symbols from /lib/libnih.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libnih.so.1
Reading symbols from /lib/libnih-dbus.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/libnih-dbus.so.1
Reading symbols from /lib/x86_64-linux-gnu/libdbus-1.so.3...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libdbus-1.so.3
Reading symbols from /lib/x86_64-linux-gnu/libudev.so.0...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libudev.so.0
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/libc.so.6
Reading symbols from /lib/x86_64-linux-gnu/librt.so.1...(no debugging symbols found)...done.
Loaded symbols for /lib/x86_64-linux-gnu/librt.so.1
Reading symbols from /lib/x86_64-linux-gnu/libpthread.so.0...(no debugging symbols found)...done.
[Thread debugging using libthread_db enabled]
Loaded symbols for /lib/x86_64-linux-gnu/libpthread.so.0
Reading symbols from /lib64/ld-linux-x86-64.so.2...(no debugging symbols found)...done.
Loaded symbols for /lib64/ld-linux-x86-64.so.2
0x00007f9d721d1bf0 in write () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt full
#0  0x00007f9d721d1bf0 in write () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#1  0x00007f9d721715f3 in _IO_file_write () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#2  0x00007f9d721714ba in ?? () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#3  0x00007f9d72171f6e in _IO_file_xsputn () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#4  0x00007f9d7214a5f6 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#5  0x00007f9d721456ee in vfprintf () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#6  0x00007f9d721f50db in __fprintf_chk () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#7  0x00007f9d726d0e34 in ?? () from /lib/x86_64-linux-gnu/libdbus-1.so.3
No symbol table info available.
#8  0x00007f9d726c3dd2 in dbus_message_iter_append_basic () from /lib/x86_64-linux-gnu/libdbus-1.so.3
No symbol table info available.
#9  0x00007f9d72f38fb0 in upstart_emit_event (proxy=0x7f9d74dae2f0, name=0x7f9d74db2aa0 "power_supply-device-added", 
    env=<optimized out>, wait=0, handler=0, error_handler=0x7f9d72f35d7c <emit_event_error>, data=0x0, timeout=2147483647)
    at com.ubuntu.Upstart.c:1018
        env_element = 0x7f9d74db10b0 "POWER_SUPPLY_MODEL_NAME=ASMB012ch\024\001\364", <incomplete sequence \340>
        method_call = 0x7f9d74db09e0
---Type <return> to continue, or q <return> to quit---
        iter = {dummy1 = 0x7f9d74db09e0, dummy2 = 0x1e00000, dummy3 = 1917452396, dummy4 = 32669, dummy5 = 1960513824, 
          dummy6 = 32669, dummy7 = 3, dummy8 = 32669, dummy9 = 1960512048, dummy10 = 32669, dummy11 = 30, pad1 = 32669, 
          pad2 = -1267369536, pad3 = 0x7f9d74db36d0}
        pending_call = <optimized out>
        pending_data = <optimized out>
        env_iter = {dummy1 = 0x7f9d74db09e0, dummy2 = 0x1e00000, dummy3 = 1917542764, dummy4 = 32669, dummy5 = 1960513824, 
          dummy6 = 32669, dummy7 = 2, dummy8 = 32669, dummy9 = 1960512048, dummy10 = 32669, dummy11 = 593, pad1 = 36, 
          pad2 = 32, pad3 = 0x7f9d74db36d0}
        __FUNCTION__ = "upstart_emit_event"
#10 0x00007f9d72f36195 in udev_monitor_watcher (udev_monitor=<optimized out>, watch=<optimized out>, 
    events=<optimized out>) at upstart-udev-bridge.c:276
        __ret = <optimized out>
        udev_device = 0x7f9d74db1cb0
        subsystem = <optimized out>
        action = <optimized out>
        kernel = 0x7f9d74db25f0 "BAT0"
        devpath = 0x7f9d74db2494 "/devices/LNXSYSTM:00/device:00/PNP0C0A:00/power_supply/BAT0"
        devname = 0x0
        name = 0x7f9d74db2aa0 "power_supply-device-added"
        env = 0x7f9d74db3580
        env_len = 19
        pending_call = <optimized out>
        __FUNCTION__ = "udev_monitor_watcher"
---Type <return> to continue, or q <return> to quit---
#11 0x00007f9d72b0143b in nih_io_handle_fds () from /lib/libnih.so.1
No symbol table info available.
#12 0x00007f9d72b05365 in nih_main_loop () from /lib/libnih.so.1
No symbol table info available.
#13 0x00007f9d7211f30d in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6
No symbol table info available.
#14 0x00007f9d72f35cb1 in _start ()
        daemonise = 1
        upstart = 0x7f9d74dae2f0
        options = {{option = 0, long_option = 0x7f9d72f3bd22 "daemon", 
            help = 0x7f9d72f3bd29 "Detach and run in the background", group = 0x0, arg_name = 0x0, value = 0x7f9d7313e0a8, 
            setter = 0}, {option = 0, long_option = 0x0, help = 0x0, group = 0x0, arg_name = 0x0, value = 0x0, setter = 0}}