[asterisk-ss7] asterisk segfault while working with chan_ss7

[Anton]

I'm experiencing a segfault of the Asterisk server while working on the production PC. While 
segfault is not inside the chan_ss7, this segfault somehow binded with it, because codec_alaw is 
receiving the BAD frame, on which it segfault's eventually. (roughly once in 24 hours - depends on the load)
The following just does not allowing asterisk server to segfault. But BAD frame generation should be cured 
somehow differently.

codec_alaw.c in the procedure alawtolin_framein

  /* Reset ssindex and signal to frame's specified values */
  b = f->data;
  if( !b ) {
   ast_log(LOG_ERROR, "BAD FRAME RECEIVED. SEGFAULT HERE!\n");
   ast_frame_dump("SEGFAULTING FRAME FRAME", f, "CODEC_ALAW");

   return 0;
  }