crash with assertion (?)

crash with assertion (?)

[IOhannes m zmoelnig]

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hi all,

(just in case: sorry for double posting, i first sent from a
non-subscribed address)

this might have been discussed already ages ago, but i didn't find much
on the web, and i'm a bit confused why it happens, so:

i'm developing/bugfixing an application using (well, obviously) alsa,
and i get crashes with assertions.

my setup:
- nvidia CK804 onboard soundcard (this soundcard seems to only be able
to run at 48kHz)
- debian squeeze/sid (libasound2 1.0.23-1)

what i'm trying to do:
i'm requesting my "plughw" device with 44100Hz
the request is done with something like:
 rate=44100;
 err = snd_pcm_hw_params_set_rate_min(handle, params, &rate, 0);
[...]
 err = snd_pcm_hw_params(handle, params);

what happens:
in the snd_pcm_hw_params(), my program exits with:
"interval_inline.h:52: snd_interval_single: Assertion
`!snd_interval_empty(i)' failed."

sidenotes:
if i use the "hw" device, i get away with the wrong samplerate (no
crash, though the requested samplerate does not take effect)


now i understand, that my soundcard does not accept 44100Hz.
what i don't understand is, that alsa-lib crashes with an assertion error.
i expect snd_pcm_hw_params() return an error!=0 if it fails to do what
it is asked to do.
imho, a library should _never ever_ crash the application.



is this a bug?
in alsa-lib? in the debian-packages?

fgmasdr
IOhannes


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Re: crash with assertion (?)

[IOhannes m zmoelnig]

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On 2010-09-07 18:05, IOhannes m zmoelnig wrote:
> hi all,
> 
> is this a bug?
> in alsa-lib? in the debian-packages?
> 

it seems like debian compiles the package without explicitely adding the
"--without-debug" configure-flag, does resulting in assert()ions that
exist the application.

i will file a bug-report with debian, so they can fix this.

in the meantime: why is it the default to compile with asserts?

fgamdf
IOhannes


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Re: crash with assertion (?)

[IOhannes m zmoelnig]

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On 2010-09-07 18:07, IOhannes m zmoelnig wrote:
> it seems like debian compiles the package without explicitely adding the
> "--without-debug" configure-flag, does resulting in assert()ions that
> exist the application.
> 
> i will file a bug-report with debian, so they can fix this.
> 
> in the meantime: why is it the default to compile with asserts?
> 

but obviously the assertion is there for a reason (so i guess i would
get crashes even if the assertion was not there, since the assert() only
protects from a NULL-pointer dereferencing)

which brings the bug back to alsa-lib....


fgamsdr
IOhannes


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Re: crash with assertion (?)

[Clemens Ladisch]

IOhannes m zmoelnig wrote:
> i'm requesting my "plughw" device with 44100Hz
> the request is done with something like:
>  rate=44100;
>  err = snd_pcm_hw_params_set_rate_min(handle, params, &rate, 0);

This requests a sample rate of at least 44100 Hz.

> [...]
>  err = snd_pcm_hw_params(handle, params);
> 
> what happens:
> in the snd_pcm_hw_params(), my program exits with:
> "interval_inline.h:52: snd_interval_single: Assertion
> `!snd_interval_empty(i)' failed."

You called snd_pcm_hw_params with an invalid params structure.
I'd guess that snd_pcm_hw_params_set_rate_min (or some other
snd_pcm_hw_params_set_*) returned an error.


Regards,
Clemens

Re: crash with assertion (?)

[IOhannes m zmoelnig]

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On 2010-09-07 19:06, Clemens Ladisch wrote:
> IOhannes m zmoelnig wrote:
>> i'm requesting my "plughw" device with 44100Hz
>> the request is done with something like:
>>  rate=44100;
>>  err = snd_pcm_hw_params_set_rate_min(handle, params, &rate, 0);
> 
> This requests a sample rate of at least 44100 Hz.

yes. this is good enough for me.
(it shouldn't crash though)

> 
>> [...]
>>  err = snd_pcm_hw_params(handle, params);
>>
>> what happens:
>> in the snd_pcm_hw_params(), my program exits with:
>> "interval_inline.h:52: snd_interval_single: Assertion
>> `!snd_interval_empty(i)' failed."
> 
> You called snd_pcm_hw_params with an invalid params structure.
> I'd guess that snd_pcm_hw_params_set_rate_min (or some other
> snd_pcm_hw_params_set_*) returned an error.

i wish you were right.
however, it seems like i am blindfolded.

i noticed however, that i need to set both the rate (i use
snd_pcm_hw_params_set_rate_min()) and the period size (i use
snd_pcm_hw_params_set_period_size_near()), in order to make it crash.

attached is an example code that triggers the crash.
please someone shed some light...

gmasdr
IOhannes


PS: that's how i use the sample program:
$ gcc -o alsatest alsatest.c $(pkg-config --cflags --libs alsa)
$ ./alsatest
trying to open 'hw:0' as CAPTURE
configuring device succeeded
CAPTURE configured
trying to open 'hw:0' as PLAYBACK
configuring device succeeded
PLAYBACK configured
trying to open 'plughw:0' as CAPTURE
configuring device succeeded
CAPTURE configured
trying to open 'plughw:0' as PLAYBACK
alsatest: interval_inline.h:55: snd_interval_single: Assertion
`!snd_interval_empty(i)' failed.
Aborted

so it seems to work fine with "hw:0" but not with "plughw:0".

you can specify the device to be opened on the cmdline:
$ ./alsatest hw:2

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#include <stdio.h>
#include <alsa/asoundlib.h>

#define ENABLE_SETPARAMS_RATE 1
#define ENABLE_SETPARAMS_PERIOD 2

/* neither set_rate_min() nor set_period_size_near() is ok (but trivial) */
//#define ENABLE_SETPARAMS 0

/* only set_rate_min() is ok */
//#define ENABLE_SETPARAMS  ENABLE_SETPARAMS_RATE

/* only set_period_size_near() is ok as well */
//#define ENABLE_SETPARAMS  ENABLE_SETPARAMS_PERIOD

/* both set_rate_min() and set_period_size_near() -> CRASH */
#define ENABLE_SETPARAMS  ENABLE_SETPARAMS_RATE | ENABLE_SETPARAMS_PERIOD

int pcm_configure(snd_pcm_t *pcm) {
  unsigned int rate=44100;
  snd_pcm_uframes_t uframes = 64;

  snd_pcm_hw_params_t* hw_params;
  int err;

  snd_pcm_hw_params_alloca(&hw_params);
  err = snd_pcm_hw_params_any(pcm, hw_params);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params_any failed: %s\n",  snd_strerror(err));return err;}

#if ENABLE_SETPARAMS & 1
  err = snd_pcm_hw_params_set_rate_min(pcm, hw_params, &rate, 0);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params_set_rate_min failed: %s\n",  snd_strerror(err));return err;}
#endif

#if ENABLE_SETPARAMS & 2
  err = snd_pcm_hw_params_set_period_size_near(pcm, hw_params, &uframes, 0);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params_set_period_size failed: %s\n",  snd_strerror(err));return err;}
#endif

  err = snd_pcm_hw_params(pcm, hw_params);
  if(err<0){fprintf(stderr, "snd_pcm_hw_params failed: %s\n",  snd_strerror(err));return err;}

  printf("configuring device succeeded\n");
  return 0;
}

void pcm_open(char*name) {
 int err=0;
 snd_pcm_t *pcmIn=0, *pcmOut=0;

  printf("trying to open '%s' as CAPTURE\n", name);
  err = snd_pcm_open(&pcmIn, name, SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK);
  if(err<0){fprintf(stderr, "snd_pcm_open(CAPTURE) failed: %s\n",  snd_strerror(err));goto closeit;}
  err=snd_pcm_nonblock(pcmIn, 1);
  if(err<0){fprintf(stderr, "snd_pcm_nonblock failed: %s\n",  snd_strerror(err));goto closeit;}
  pcm_configure(pcmIn);
  fprintf(stderr, "CAPTURE configured\n");

  printf("trying to open '%s' as PLAYBACK\n", name);
  err = snd_pcm_open(&pcmOut, name, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
  if(err<0){fprintf(stderr, "snd_pcm_open(PLAYBACK) failed: %s\n",  snd_strerror(err));goto closeit;}
  err=snd_pcm_nonblock(pcmOut, 1);
  if(err<0){fprintf(stderr, "snd_pcm_nonblock failed: %s\n",  snd_strerror(err));goto closeit;}
  pcm_configure(pcmOut);
  fprintf(stderr, "PLAYBACK configured\n");

 closeit:
  if(pcmIn)snd_pcm_close(pcmIn);
  if(pcmOut)snd_pcm_close(pcmOut);
}


int main(int argc, char**argv) {
  int i=0;
  if(argc>1) {
    for(i=1; i<argc; i++) {
      pcm_open(argv[i]);
    }
  } else {
      pcm_open("hw:0");
      pcm_open("plughw:0");
  }
  fprintf(stderr, "bye bye\n");
  return 0;
}

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Re: crash with assertion (?)

[Raymond Yau]

2010/9/8 IOhannes m zmoelnig <zmoelnig@iem.at>

> On 2010-09-07 19:06, Clemens Ladisch wrote:
> > IOhannes m zmoelnig wrote:
> >> i'm requesting my "plughw" device with 44100Hz
> >> the request is done with something like:
> >>  rate=44100;
> >>  err = snd_pcm_hw_params_set_rate_min(handle, params, &rate, 0);
> >
> > This requests a sample rate of at least 44100 Hz.
>
> yes. this is good enough for me.
> (it shouldn't crash though)
>
>
http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___h_w___params.htm

Restrict a configuration space with a minimum rate.

val approximate minimum rate ( on return filled with actul minimum )
dir sub unit direction (on return filled with actual direction)

Return 0 otherwise a negative error code if configuration space would become
empty



what is the minimum rate returned by snd_pcm_hw_params_get_rate_min() when
using hw:0,0 ?

>
> >> [...]
> >>  err = snd_pcm_hw_params(handle, params);
> >>
> >> what happens:
> >> in the snd_pcm_hw_params(), my program exits with:
> >> "interval_inline.h:52: snd_interval_single: Assertion
> >> `!snd_interval_empty(i)' failed."
> >
> > You called snd_pcm_hw_params with an invalid params structure.
> > I'd guess that snd_pcm_hw_params_set_rate_min (or some other
> > snd_pcm_hw_params_set_*) returned an error.
>
> i wish you were right.
> however, it seems like i am blindfolded.
>
> i noticed however, that i need to set both the rate (i use
> snd_pcm_hw_params_set_rate_min()) and the period size (i use
> snd_pcm_hw_params_set_period_size_near()), in order to make it crash.
>
> attached is an example code that triggers the crash.
> please someone shed some light...
>
> gmasdr
> IOhannes
>
>
> PS: that's how i use the sample program:
> $ gcc -o alsatest alsatest.c $(pkg-config --cflags --libs alsa)
> $ ./alsatest
> trying to open 'hw:0' as CAPTURE
> configuring device succeeded
> CAPTURE configured
> trying to open 'hw:0' as PLAYBACK
> configuring device succeeded
> PLAYBACK configured
> trying to open 'plughw:0' as CAPTURE
> configuring device succeeded
> CAPTURE configured
> trying to open 'plughw:0' as PLAYBACK
> alsatest: interval_inline.h:55: snd_interval_single: Assertion
> `!snd_interval_empty(i)' failed.
> Aborted
>
> so it seems to work fine with "hw:0" but not with "plughw:0".
>
> you can specify the device to be opened on the cmdline:
> $ ./alsatest hw:2
>
>

To debug , you will need to enable RULES_DEBUG In pcm_params.c

add snd_pcm_dump() after snd_pcm_hw_params in your program

export LIBASOUND_DEBUG=1

and post the output of your program

Re: crash with assertion (?)

[IOhannes m zmoelnig]

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On 2010-09-09 03:30, Raymond Yau wrote:

> http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___h_w___params.htm
l

> what is the minimum rate returned by snd_pcm_hw_params_get_rate_min() when
> using hw:0,0 ?

for hw:0,0 it is 48000, direction=0
for plughw:0,0 i get 4000(sic!), direction=0

> 
> To debug , you will need to enable RULES_DEBUG In pcm_params.c
> 
> add snd_pcm_dump() after snd_pcm_hw_params in your program
> 
> export LIBASOUND_DEBUG=1
> 
> and post the output of your program

ok, i tried that.
there's of course the little problem with havind snd_pcm_dump() after
snd_pcm_hw_params(), since the latter crashes...
so i added it before i start configuring the device as well. here's the
pseudocode:
<snip>
open(PLAYBACK);
dump();
nonblock(1); get_rate(); set_rate(44100); set_period(64);
dump();
close();
open(CAPTURE);
dump();
nonblock(1); get_rate(); set_rate(44100); set_period(64); /* CRASH */
dump();
close();
</snip>

i prefixed all the printout of my application with "JMZ", so you can
easily filter it out.

fgmasdr
IOhannes


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Re: crash with assertion (?)

[Raymond Yau]

2010/9/9 IOhannes m zmoelnig <zmoelnig@iem.at>

> On 2010-09-09 03:30, Raymond Yau wrote:
>
> >
> http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___h_w___params.htm
> l
>
> > what is the minimum rate returned by snd_pcm_hw_params_get_rate_min()
> when
> > using hw:0,0 ?
>
> for hw:0,0 it is 48000, direction=0
> for plughw:0,0 i get 4000(sic!), direction=0
>


Are there any reason which you need to use snd_pcm_hw_params_set_rate_min()
instead of snd_pcm_hw_params_set_rate_near() ?


set_rate_min( 44100) only restrict a configuration space with a minimum rate
and this is not sufficient for alsa-lib to refine the parameters of
snd_pcm_hw_params() to unique value when the device is plughw and your sound
card only support 48000Hz and 96000Hz

Yes, I can reprodued the assertion with a patched intel8x0 driver inside
virtualbox
since there is no error when using the emulated ac97 controller and codec
which support 8000Hz<->48000Hz

There is no error when change to use set_rate_near instead of set_rate_min



>
> >
> > To debug , you will need to enable RULES_DEBUG In pcm_params.c
> >
> > add snd_pcm_dump() after snd_pcm_hw_params in your program
> >
> > export LIBASOUND_DEBUG=1
> >
> > and post the output of your program
>
> ok, i tried that.
> there's of course the little problem with havind snd_pcm_dump() after
> snd_pcm_hw_params(), since the latter crashes...
> so i added it before i start configuring the device as well. here's the
> pseudocode:
> <snip>
> open(PLAYBACK);
> dump();
> nonblock(1); get_rate(); set_rate(44100); set_period(64);
> dump();
> close();
> open(CAPTURE);
> dump();
> nonblock(1); get_rate(); set_rate(44100); set_period(64); /* CRASH */
> dump();
> close();
> </snip>
>
> i prefixed all the printout of my application with "JMZ", so you can
> easily filter it out.
>
> fgmasdr
> IOhannes
>
>
>
schange 'plughw:0,0' (slave)
ACCESS:  MMAP_INTERLEAVED RW_INTERLEAVED
FORMAT:  S16_LE
SUBFORMAT:  STD
SAMPLE_BITS: 16
FRAME_BITS: [32 128]
CHANNELS: [2 8]
RATE: [48000 96000]
PERIOD_TIME: (20 341334)
PERIOD_SIZE: [2 16384]
PERIOD_BYTES: [32 131072]
PERIODS: [1 1024]
BUFFER_TIME: (20 341334)
BUFFER_SIZE: [2 16384]
BUFFER_BYTES: [32 65536]
TICK_TIME: ALL
ALSA ERROR hw_params: set (RATE)
           value = 44100 : Invalid argument
ACCESS:  MMAP_INTERLEAVED RW_INTERLEAVED
FORMAT:  S16_LE
SUBFORMAT:  STD
SAMPLE_BITS: 16
FRAME_BITS: [32 128]
CHANNELS: [2 8]
RATE: [48000 96000]
PERIOD_TIME: (20 341334)
PERIOD_SIZE: [2 16384]
PERIOD_BYTES: [32 131072]
PERIODS: [1 1024]
BUFFER_TIME: (20 341334)
BUFFER_SIZE: [2 16384]
BUFFER_BYTES: [32 65536]
TICK_TIME: ALL
ALSA ERROR hw_params: set (RATE)
           value = 88200 : Invalid argument
ACCESS:  MMAP_INTERLEAVED RW_INTERLEAVED
FORMAT:  S16_LE
SUBFORMAT:  STD
SAMPLE_BITS: 16
FRAME_BITS: [32 128]
CHANNELS: [2 8]
RATE: [48000 96000]
PERIOD_TIME: (20 341334)
PERIOD_SIZE: [2 16384]
PERIOD_BYTES: [32 131072]
PERIODS: [1 1024]
BUFFER_TIME: (20 341334)
BUFFER_SIZE: [2 16384]
BUFFER_BYTES: [32 65536]
TICK_TIME: ALL
srefine 'plughw:0,0' (client)
ACCESS:  MMAP_INTERLEAVED
FORMAT:  S8
SUBFORMAT:  STD
SAMPLE_BITS: 8
FRAME_BITS: 8
CHANNELS: 1
RATE: [44100 44100]
PERIOD_TIME: (83 1452)
PERIOD_SIZE: 64
PERIOD_BYTES: 64
PERIODS: (0 4113)
BUFFER_TIME: (3 5968186)
BUFFER_SIZE: [3 263197]
BUFFER_BYTES: [3 263197]
TICK_TIME: ALL
srefine 'plughw:0,0' (slave)
ACCESS:  MMAP_INTERLEAVED RW_INTERLEAVED
FORMAT:  S16_LE
SUBFORMAT:  STD
SAMPLE_BITS: 16
FRAME_BITS: 32
CHANNELS: 2
RATE: 48000
PERIOD_TIME: (166 1452)
PERIOD_SIZE: [8 16384]
PERIOD_BYTES: [32 65536]
PERIODS: [1 1024]
BUFFER_TIME: (166 341334)
BUFFER_SIZE: [8 16384]
BUFFER_BYTES: [32 65536]
TICK_TIME: ALL
cchange 'plughw:0,0'

The assertion occur becacuse  RATE=44100 -> NONE

Rule 5 (0xb7773aa0): FRAME_BITS=8 -> 8 BUFFER_BYTES=[3 263197]
BUFFER_SIZE=[7 15052]
Rule 7 (0xb7773aa0): RATE=44100 -> NONE PERIOD_SIZE=64 PERIOD_TIME=(166
1438)

alsatest: interval_inline.h:52: snd_interval_single: Assertion
`!snd_interval_empty(i)' failed.

Re: crash with assertion (?)

[Clemens Ladisch]

Raymond Yau wrote:
> Yes, I can reprodued the assertion with a patched intel8x0 driver inside
> virtualbox
> since there is no error when using the emulated ac97 controller and codec
> which support 8000Hz<->48000Hz

How exactly did you patch it?

> Rule 7 (0xb7773aa0): RATE=44100 -> NONE PERIOD_SIZE=64 PERIOD_TIME=(166
> 1438)
> 
> alsatest: interval_inline.h:52: snd_interval_single: Assertion
> `!snd_interval_empty(i)' failed.

This looks like a definite bug.


Regards,
Clemens

Re: crash with assertion (?)

[Raymond Yau]

2010/9/10 Clemens Ladisch <clemens@ladisch.de>

> Raymond Yau wrote:
> > Yes, I can reprodued the assertion with a patched intel8x0 driver inside
> > virtualbox
> > since there is no error when using the emulated ac97 controller and codec
> > which support 8000Hz<->48000Hz
>
> How exactly did you patch it?
>

based on his log and his card seem support rate 48000 and 96000 only

 SNDRV_PCM_RATE_48000 | SNDRV_PCM_RATE_96000

the assertion also occur with snd-dummy model=ac97 with the above change in
rate constraint on Fedora 13

may need the output of alsa-info.sh to find out his ac97 codec and
snd_pcm_dump to find out the resampler