libavcodec/aac.c:1618: error: Null Dereference
  pointer `&gb->buffer` last assigned on line 1616 could be null and is dereferenced by call to `show_bits()` at line 1618, column 9.

libavcodec/aac.c:1607:1: start of procedure aac_decode_frame()
1605. }
1606. 
1607. static int aac_decode_frame(AVCodecContext * avccontext, void * data, int * data_size, AVPacket *avpkt) {
      ^
1608.     const uint8_t *buf = avpkt->data;
1609.     int buf_size = avpkt->size;

libavcodec/aac.c:1608:5: 
1606. 
1607. static int aac_decode_frame(AVCodecContext * avccontext, void * data, int * data_size, AVPacket *avpkt) {
1608.     const uint8_t *buf = avpkt->data;
          ^
1609.     int buf_size = avpkt->size;
1610.     AACContext * ac = avccontext->priv_data;

libavcodec/aac.c:1609:5: 
1607. static int aac_decode_frame(AVCodecContext * avccontext, void * data, int * data_size, AVPacket *avpkt) {
1608.     const uint8_t *buf = avpkt->data;
1609.     int buf_size = avpkt->size;
          ^
1610.     AACContext * ac = avccontext->priv_data;
1611.     ChannelElement * che = NULL;

libavcodec/aac.c:1610:5: 
1608.     const uint8_t *buf = avpkt->data;
1609.     int buf_size = avpkt->size;
1610.     AACContext * ac = avccontext->priv_data;
          ^
1611.     ChannelElement * che = NULL;
1612.     GetBitContext gb;

libavcodec/aac.c:1611:5: 
1609.     int buf_size = avpkt->size;
1610.     AACContext * ac = avccontext->priv_data;
1611.     ChannelElement * che = NULL;
          ^
1612.     GetBitContext gb;
1613.     enum RawDataBlockType elem_type;

libavcodec/aac.c:1616:5: 
1614.     int err, elem_id, data_size_tmp;
1615. 
1616.     init_get_bits(&gb, buf, buf_size*8);
          ^
1617. 
1618.     if (show_bits(&gb, 12) == 0xfff) {

libavcodec/get_bits.h:493:1: start of procedure init_get_bits()
  491.  * @param bit_size the size of the buffer in bits
  492.  */
  493. static inline void init_get_bits(GetBitContext *s,
       ^
  494.                    const uint8_t *buffer, int bit_size)
  495. {

libavcodec/get_bits.h:496:5: 
  494.                    const uint8_t *buffer, int bit_size)
  495. {
  496.     int buffer_size= (bit_size+7)>>3;
           ^
  497.     if(buffer_size < 0 || bit_size < 0) {
  498.         buffer_size = bit_size = 0;

libavcodec/get_bits.h:497:8: Taking true branch
  495. {
  496.     int buffer_size= (bit_size+7)>>3;
  497.     if(buffer_size < 0 || bit_size < 0) {
              ^
  498.         buffer_size = bit_size = 0;
  499.         buffer = NULL;

libavcodec/get_bits.h:498:9: 
  496.     int buffer_size= (bit_size+7)>>3;
  497.     if(buffer_size < 0 || bit_size < 0) {
  498.         buffer_size = bit_size = 0;
               ^
  499.         buffer = NULL;
  500.     }

libavcodec/get_bits.h:499:9: 
  497.     if(buffer_size < 0 || bit_size < 0) {
  498.         buffer_size = bit_size = 0;
  499.         buffer = NULL;
               ^
  500.     }
  501. 

libavcodec/get_bits.h:502:5: 
  500.     }
  501. 
  502.     s->buffer= buffer;
           ^
  503.     s->size_in_bits= bit_size;
  504.     s->buffer_end= buffer + buffer_size;

libavcodec/get_bits.h:503:5: 
  501. 
  502.     s->buffer= buffer;
  503.     s->size_in_bits= bit_size;
           ^
  504.     s->buffer_end= buffer + buffer_size;
  505. #ifdef ALT_BITSTREAM_READER

libavcodec/get_bits.h:504:5: 
  502.     s->buffer= buffer;
  503.     s->size_in_bits= bit_size;
  504.     s->buffer_end= buffer + buffer_size;
           ^
  505. #ifdef ALT_BITSTREAM_READER
  506.     s->index=0;

libavcodec/get_bits.h:506:5: 
  504.     s->buffer_end= buffer + buffer_size;
  505. #ifdef ALT_BITSTREAM_READER
  506.     s->index=0;
           ^
  507. #elif defined LIBMPEG2_BITSTREAM_READER
  508.     s->buffer_ptr = (uint8_t*)((intptr_t)buffer&(~1));

libavcodec/get_bits.h:516:1: return from a call to init_get_bits
  514.     skip_bits_long(s, 0);
  515. #endif
  516. }
       ^
  517. 
  518. static inline void align_get_bits(GetBitContext *s)

libavcodec/aac.c:1618:9: 
1616.     init_get_bits(&gb, buf, buf_size*8);
1617. 
1618.     if (show_bits(&gb, 12) == 0xfff) {
              ^
1619.         if ((err = parse_adts_frame_header(ac, &gb)) < 0) {
1620.             av_log(avccontext, AV_LOG_ERROR, "Error decoding AAC frame header.\n");

libavcodec/get_bits.h:399:1: start of procedure show_bits()
  397.  * Note, the alt bitstream reader can read up to 25 bits, but the libmpeg2 reader can't
  398.  */
  399. static inline unsigned int show_bits(GetBitContext *s, int n){
       ^
  400.     register int tmp;
  401.     OPEN_READER(re, s)

libavcodec/get_bits.h:401:5: 
  399. static inline unsigned int show_bits(GetBitContext *s, int n){
  400.     register int tmp;
  401.     OPEN_READER(re, s)
           ^
  402.     UPDATE_CACHE(re, s)
  403.     tmp= SHOW_UBITS(re, s, n);

libavcodec/get_bits.h:402:5: 
  400.     register int tmp;
  401.     OPEN_READER(re, s)
  402.     UPDATE_CACHE(re, s)
           ^
  403.     tmp= SHOW_UBITS(re, s, n);
  404. //    CLOSE_READER(re, s)
