[alsa-devel] ALSA Leaking memory

[Jaroslav Kysela]

On Sun, 25 Nov 2007, Lennart Poettering wrote:

> Hi!
> 
> Apparently alsa-libs .15 is leaking memory when using snd_pcm_open()
> on some devices that cannot be opened. 
> 
> On my USB wecam which has only a single mono audio stream, opening it
> as "front:3" (which of course fails) leaks a bit of memory. Consider this example:
> 
> <snip>
> #include <asoundlib.h>
> #include <assert.h>
> 
> int main(int argc, char *argv[]) {
>     snd_pcm_t *pcm;
> 
>     if (snd_pcm_open(&pcm, "front:3", SND_PCM_STREAM_CAPTURE,
>     SND_PCM_NONBLOCK) == 0) {
>         int r = snd_pcm_close(pcm);
>         assert(r == 0);
>     }
> 
>     snd_config_update_free_global();
>     return 0;
> }
> </snip>
> 
> And there they are gone, the 10 bytes of memory. Here's a snippet from valgrinding this program:
> 
> ==22198== 10 bytes in 1 blocks are definitely lost in loss record 1 of 3
> ==22198==    at 0x4023765: malloc (vg_replace_malloc.c:149)
> ==22198==    by 0x417C44F: strdup (strdup.c:43)
> ==22198==    by 0x4071954: snd_determine_driver (in /usr/lib/libasound.so.2.0.0)
> ==22198==    by 0x406E80C: snd_config_hook_load_for_all_cards (in /usr/lib/libasound.so.2.0.0)
> ==22198==    by 0x406EC7C: (within /usr/lib/libasound.so.2.0.0) 
> ==22198==    by 0x406F896: snd_config_searcha_hooks (in /usr/lib/libasound.so.2.0.0)
> ==22198==    by 0x406FA74: snd_config_search_alias_hooks (in /usr/lib/libasound.so.2.0.0)
> ==22198==    by 0x406FCD9: snd_config_search_definition (in /usr/lib/libasound.so.2.0.0)
> ==22198==    by 0x40952FE: (within /usr/lib/libasound.so.2.0.0)
> ==22198==    by 0x80484D7: main (in /home/lennart/alsa-test)

Broken valgrind? I cannot reproduce here and from first glance, the error 
path in snd_config_hook_load_for_all_cards is good.

						Jaroslav

-----
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project