Re: Segmentation Fault in snd_pcm_rate_hw_free()

[Takashi Iwai <tiwai@suse.de>]

On Tue, 04 Aug 2015 16:08:30 +0200,
Valentin Corfu wrote:
> 
> Hello ALSA developers,
> 
> I observed one segmentation fault in snd_pcm_rate_hw_free() function, 
> with the following BT:
> 
> (gdb) up
> #1  0xb7554cc1 in raise (sig=6) at 
> ../nptl/sysdeps/unix/sysv/linux/raise.c:64
> 64        return INLINE_SYSCALL (tgkill, 3, pid, selftid, sig);
> (gdb)
> #2  0xb75580ee in abort () at abort.c:92
> 92            raise (SIGABRT);
> (gdb)
> #3  0xb758a7dd in __libc_message (do_abort=2,
>      fmt=0xb766053c "*** glibc detected *** %s: %s: 0x%s ***\n")
>      at ../sysdeps/unix/sysv/linux/libc_fatal.c:189
> 189           abort ();
> (gdb)
> #4  0xb7594a71 in malloc_printerr (action=<value optimized out>,
>      str=<value optimized out>, ptr=0x969ae98) at malloc.c:6283
> 6283          __libc_message (action & 2,
> (gdb)
> #5  0xb759636b in _int_free (av=<value optimized out>, p=0x969ae90)
>      at malloc.c:4795
> 4795          malloc_printerr (check_action, errstr, chunk2mem(p));
> (gdb)
> #6  0xb75994bd in __libc_free (mem=0x969ae98) at malloc.c:3738
> 3738      _int_free(ar_ptr, p);
> (gdb)
> #7  0xb76f3a81 in snd_pcm_rate_hw_free (pcm=0x9685d78) at pcm_rate.c:341
> 341                     free(rate->pareas[0].addr);

Could you check the content of rate->pareas[0] via gdb?

> (gdb)
> #8  0xb76d045b in snd_pcm_hw_free (pcm=0x9685d78) at pcm.c:858
> 858             err = pcm->ops->hw_free(pcm->op_arg);
> (gdb)
> #9  0xb76f826e in snd_pcm_plug_hw_free (pcm=0x96856b0) at pcm_plug.c:1046
> 1046            int err = snd_pcm_hw_free(slave);
> (gdb)
> #10 0xb76d045b in snd_pcm_hw_free (pcm=0x96856b0) at pcm.c:858
> 858             err = pcm->ops->hw_free(pcm->op_arg);
> (gdb)
> #11 0x080492ad in main ()
> 
> 
> Could you please give me some hints how to solve this issue?
> 
> I can provide you more info or the test application, if needed.
> I can see the issue every time, and I also checked with latest version 
> of alsa-lib but I got the same results.

I don't know of such an error, so far.
It smells like some memory corruption to me.

If a test case is a simple code, tracking the bug would be easy...


Takashi