aplay segfaults with custom .asoundrc

With the following ~/.asoundrc file the aplay program from alsa-utils package version 1.0.11-6ubuntu2 segfaults in verbose mode.

------------ .asoundrc
pcm.20to51 {
        type plug
        slave.pcm cutoffsub
        slave.channels 6
        ttable {
                0.0 1
                1.1 1
                0.2 1
                1.3 1
                0.4 0.5
                1.4 0.5
                0.5 0.5
                1.5 0.5
        }
}

pcm.cutoffsub {
        type ladspa
        slave.pcm "plughw:0,0"
        path "/usr/lib/ladspa"
        plugins {
                0 {
                        label lp4pole_fcrcia_oa
                        policy none
                        input.bindings.5 "Input";
                        output.bindings.5 "Output";
                        input {
                                controls [ 300 0 ]
                        }
                }
                1 {
                        label delay_0.01s
                        input.bindings.0 "Input";
                        output.bindings.0 "Output";
                        input {
                                controls [ 0 1 ]
                        }
                }
        }
}
------------ .asoundrc

------------ The output of aplay
$ aplay -v -D 20to51 ~/test.wav
Playing WAVE '/home/gorka/test.wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
Plug PCM: Route conversion PCM (sformat=S16_LE)
  Transformation table:
    0 <- 0
    1 <- 1
    2 <- 0
    3 <- 1
    4 <- 0*0.5 + 1*0.5
    5 <- 0*0.5 + 1*0.5
Its setup is:
  stream : PLAYBACK
  access : RW_INTERLEAVED
  format : S16_LE
  subformat : STD
  channels : 2
  rate : 44100
  exact rate : 44100 (44100/1)
  msbits : 16
  buffer_size : 2049
  period_size : 683
  period_time : 15487
  tick_time : 4000
  tstamp_mode : NONE
  period_step : 1
  sleep_min : 0
  avail_min : 683
  xfer_align : 683
  start_threshold : 2049
  stop_threshold : 2049
  silence_threshold: 0
  silence_size : 0
  boundary : 1074266112
Slave: Linear Integer <-> Linear Float conversion PCM (FLOAT_LE)
Its setup is:
  stream : PLAYBACK
  access : MMAP_INTERLEAVED
  format : S16_LE
  subformat : STD
  channels : 6
  rate : 44100
  exact rate : 44100 (44100/1)
  msbits : 16
  buffer_size : 2049
  period_size : 683
  period_time : 15487
  tick_time : 4000
  tstamp_mode : NONE
  period_step : 1
  sleep_min : 0
  avail_min : 683
  xfer_align : 683
  start_threshold : 2049
  stop_threshold : 2049
  silence_threshold: 0
  silence_size : 0
  boundary : 1074266112
Slave: LADSPA PCM
  Playback:
    Policy: none
    Filename: /usr/lib/ladspa/lp4pole_1671.so
    Plugin Name: 4 Pole Low-Pass Filter with Resonance (FCRCIA)
    Plugin Label: lp4pole_fcrcia_oa
    Plugin Unique ID: 1672
    Instances:
      Depth: 0
         InChannels: 0, 1, 2, 3, 4, 5
         InPorts: -Segmentation fault
------------ The output of aplay

------------ backtrace from gdb
#0 0xb7da1c0b in strlen () from /lib/tls/i686/cmov/libc.so.6
#1 0xb7d74874 in _IO_vfprintf_internal () from /lib/tls/i686/cmov/libc.so.6
#2 0xb7d750b2 in buffered_vfprintf () from /lib/tls/i686/cmov/libc.so.6
#3 0xb7d71020 in _IO_vfprintf_internal () from /lib/tls/i686/cmov/libc.so.6
#4 0xb7ed1348 in snd_output_stdio_open () from /usr/lib/libasound.so.2
#5 0xb7ed1371 in snd_output_printf () from /usr/lib/libasound.so.2
#6 0xb7f19842 in snd_pcm_lfloat_convert_integer_float ()
   from /usr/lib/libasound.so.2
#7 0xb7f19a3c in snd_pcm_lfloat_convert_integer_float ()
   from /usr/lib/libasound.so.2
#8 0xb7f19b14 in snd_pcm_lfloat_convert_integer_float ()
   from /usr/lib/libasound.so.2
#9 0xb7ee8160 in snd_pcm_dump () from /usr/lib/libasound.so.2
#10 0xb7f182f6 in _snd_pcm_lfloat_open () from /usr/lib/libasound.so.2
#11 0xb7ee8160 in snd_pcm_dump () from /usr/lib/libasound.so.2
#12 0xb7eff248 in snd_pcm_route_determine_ttable ()
   from /usr/lib/libasound.so.2
#13 0xb7ee8160 in snd_pcm_dump () from /usr/lib/libasound.so.2
#14 0xb7f09d52 in _snd_pcm_plug_open () from /usr/lib/libasound.so.2
#15 0xb7ee8160 in snd_pcm_dump () from /usr/lib/libasound.so.2
#16 0x0804b892 in ?? ()
#17 0x08079678 in ?? ()
#18 0x08054028 in ?? ()
#19 0x000002ab in ?? ()
#20 0x00000000 in ?? ()
------------ backtrace from gdb