[alsa-devel] Random process lockup on ARM board: alsa-lib-1.0.25, FUTEX_WAIT_PRIVATE
jon at jonshouse.co.uk
Thu Feb 16 13:01:31 CET 2012
Sorry all me again.
I've written a program that picks up UDP broadcast packets containing
audio from a number of sources, mixes it together and presents it to
alsa for playback.
I'm experiencing random freezes. I cant reproduce then running the
process under strace as the process on the ARM board slows down to the
point it underruns with ALSA all the time and the symptom doesn't show.
If I attach strace after the process has frozen I get this and nothing
# strace -p 443
Process 443 attached - interrupt to quit
futex(0x4030e144, FUTEX_WAIT_PRIVATE, 2, NULL
This stop happens at random at any point typically after minutes but run
time can be over an hour.
I need to work around this as I need the board for a demo.
Im using, alsa-lib-1.0.25
I also compiled strace for arm, but this and a busybox shell is the only
environment I have on the board.
The problem showed when I starting using this function to poll alsa:
The same code on my PC dual core AMD does not seem to suffer the
problem : alsa-lib-1.0.23, Linux jonspc 126.96.36.199-175.fc12.i686 #1 SMP
Before anyone points it out I want to poll as alsa is not the only sound
output supported by the code.
snd_pcm_status_alloca( &status );
// If the alsa playback has stalled then it definately needs data
if( snd_pcm_status_get_state( status ) != SND_PCM_STATE_RUNNING )
# cat /proc/443/status
State: S (sleeping)
Uid: 0 0 0 0
Gid: 0 0 0 0
VmPeak: 4356 kB
VmSize: 4292 kB
VmLck: 132 kB
VmHWM: 1788 kB
VmRSS: 1788 kB
VmData: 396 kB
VmStk: 136 kB
VmExe: 28 kB
VmLib: 3348 kB
VmPTE: 12 kB
VmSwap: 0 kB
Any useful suggestions welcome.
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