[Pkg-alsa-devel] Bug#679815: alsa-base: Consistent segfaults with short upmixing config (ca-0106)

[Matthew Toseland]

Package: alsa-base
Version: 1.0.23+dfsg-2
Severity: normal


I have been trying to get upmixing+dmix working, and have tried various complex config's from the web, and these cause consistent segfaults, which suggests a serious bug (none of the configs is particularly unusual). I have managed to reduce the config file somewhat... One of the originals was the second config here: http://ds.mcbf.net/wiki/DotAsoundrc

All applications using alsa (e.g. the speaker tester program and ogg123) segfault consistently with dmixer enabled as below. Commenting out the "bindings" section solves the segfault, but then upmix_21to51 (what I was originally trying to do) will fail:
ALSA lib pcm_params.c:2150:(snd1_pcm_hw_refine_slave) Slave PCM not usable
ERROR: Cannot open device alsa.

To test the segfault:
Set .asoundrc as below.
Test with "ogg123 -d alsa -o dev:dmixer <ogg file to play>"
This also segfaults with other alsa applications, e.g. speaker-test.

I think this is alsa-base but it might be plugins; it's in dmix anyway.

pcm.dmixer {
  type dmix
  ipc_key 4821
  ipc_key_add_uid false
  ipc_perm 0660
  slave {
    pcm "hw:0"
    rate 48000
    channels 6
    period_time 0
    period_size 1024
    buffer_time 0
    buffer_size 65535
  }
  bindings {
      0 0
      1 1
      2 2
      3 3
      4 4
      5 5
  }
}

pcm.upmix_21to51 {
  type plug
  slave.pcm "dmixer"
  slave.channels 6
  ttable {
    0.0 1 # front left
    1.1 1 # front right
    0.2 1 # rear left
    1.3 1 # rear right
    0.4 0.5 # center
    1.4 0.5 # center
    2.5 1 # subwoofer
  }
}

-- Package-specific info:
--- Begin additional package status ---
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name           Version        Description
+++-==============-==============-============================================
ii  libasound2     1.0.23-2.1     shared library for ALSA applications
--- End additional package status ---
--- Begin /proc/asound/version ---
Advanced Linux Sound Architecture Driver Version 1.0.21.
--- End /proc/asound/version ---
--- Begin /proc/asound/cards ---
 0 [CA0106         ]: CA0106 - CA0106
                      Audigy SE [SB0570] at 0xcc00 irq 21
--- End /proc/asound/cards ---
--- Begin /dev/snd/ listing ---
total 0
drwxr-xr-x  2 root root       60 Jul  1 19:07 by-path
crw-rw----+ 1 root audio 116, 13 Jul  1 19:07 controlC0
crw-rw----+ 1 root audio 116,  4 Jul  1 19:07 midiC0D0
crw-rw----+ 1 root audio 116, 12 Jul  1 19:07 pcmC0D0c
crw-rw----+ 1 root audio 116, 11 Jul  1 19:15 pcmC0D0p
crw-rw----+ 1 root audio 116, 10 Jul  1 19:07 pcmC0D1c
crw-rw----+ 1 root audio 116,  9 Jul  1 19:07 pcmC0D1p
crw-rw----+ 1 root audio 116,  8 Jul  1 19:07 pcmC0D2c
crw-rw----+ 1 root audio 116,  7 Jul  1 19:07 pcmC0D2p
crw-rw----+ 1 root audio 116,  6 Jul  1 19:07 pcmC0D3c
crw-rw----+ 1 root audio 116,  5 Jul  1 19:07 pcmC0D3p
crw-rw----+ 1 root audio 116,  3 Jul  1 19:07 seq
crw-rw----+ 1 root audio 116,  2 Jul  1 19:07 timer
--- End /dev/snd/ listing ---

-- System Information:
Debian Release: 6.0.5
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.32-5-amd64 (SMP w/6 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages alsa-base depends on:
ii  linux-sound-base           1.0.23+dfsg-2 base package for ALSA and OSS soun
ii  lsof                       4.81.dfsg.1-1 List open files
ii  module-init-tools          3.12-2        tools for managing Linux kernel mo
ii  udev                       164-3         /dev/ and hotplug management daemo

Versions of packages alsa-base recommends:
ii  alsa-utils                    1.0.23-3   Utilities for configuring and usin

Versions of packages alsa-base suggests:
ii  alsa-oss                      1.0.17-4   ALSA wrapper for OSS applications
pn  apmd                          <none>     (no description available)
ii  oss-compat                    0.0.4+nmu3 OSS compatibility package

Versions of packages libasound2 depends on:
ii  libc6                         2.11.3-3   Embedded GNU C Library: Shared lib

-- Configuration Files:
/etc/modprobe.d/alsa-base-blacklist.conf changed:
blacklist snd-hda-intel
blacklist snd-pcsp

/etc/modprobe.d/alsa-base.conf changed:
install sound-slot-0 /sbin/modprobe snd-card-0
install sound-slot-1 /sbin/modprobe snd-card-1
install sound-slot-2 /sbin/modprobe snd-card-2
install sound-slot-3 /sbin/modprobe snd-card-3
install sound-slot-4 /sbin/modprobe snd-card-4
install sound-slot-5 /sbin/modprobe snd-card-5
install sound-slot-6 /sbin/modprobe snd-card-6
install sound-slot-7 /sbin/modprobe snd-card-7
install snd /sbin/modprobe --ignore-install snd && { /sbin/modprobe --quiet snd-ioctl32 ; /sbin/modprobe --quiet snd-seq ; }
install snd-rawmidi /sbin/modprobe --ignore-install snd-rawmidi && { /sbin/modprobe --quiet snd-seq-midi ; : ; }
install snd-emu10k1 /sbin/modprobe --ignore-install snd-emu10k1 && { /sbin/modprobe --quiet snd-emu10k1-synth ; : ; }
options bt87x index=-2
options cx88_alsa index=-2
options snd-atiixp-modem index=-2
options snd-intel8x0m index=-2
options snd-via82xx-modem index=-2
options snd-pcsp index=-2


-- debconf-show failed