libavformat/oggdec.c:66: error: Null Dereference
  pointer `ost` last assigned on line 63 could be null and is dereferenced at line 66, column 5.

libavformat/oggdec.c:60:1: start of procedure ogg_save()
58. 
59. //FIXME We could avoid some structure duplication
60. static int ogg_save(AVFormatContext *s)
    ^
61. {
62.     struct ogg *ogg = s->priv_data;

libavformat/oggdec.c:62:5: 
60. static int ogg_save(AVFormatContext *s)
61. {
62.     struct ogg *ogg = s->priv_data;
        ^
63.     struct ogg_state *ost =
64.         av_malloc(sizeof(*ost) + (ogg->nstreams - 1) * sizeof(*ogg->streams));

libavformat/oggdec.c:63:5: 
61. {
62.     struct ogg *ogg = s->priv_data;
63.     struct ogg_state *ost =
        ^
64.         av_malloc(sizeof(*ost) + (ogg->nstreams - 1) * sizeof(*ogg->streams));
65.     int i;

libavutil/mem.c:61:1: start of procedure av_malloc()
  59.  * linker will do it automatically. */
  60. 
  61. void *av_malloc(size_t size)
      ^
  62. {
  63.     void *ptr = NULL;

libavutil/mem.c:63:5: 
  61. void *av_malloc(size_t size)
  62. {
  63.     void *ptr = NULL;
          ^
  64. #if CONFIG_MEMALIGN_HACK
  65.     long diff;

libavutil/mem.c:69:9: Taking false branch
  67. 
  68.     /* let's disallow possibly ambiguous cases */
  69.     if (size > (INT_MAX - 32) || !size)
              ^
  70.         return NULL;
  71. 

libavutil/mem.c:69:35: Taking false branch
  67. 
  68.     /* let's disallow possibly ambiguous cases */
  69.     if (size > (INT_MAX - 32) || !size)
                                        ^
  70.         return NULL;
  71. 

libavutil/mem.c:80:9: Taking true branch
  78.     ((char *)ptr)[-1] = diff;
  79. #elif HAVE_POSIX_MEMALIGN
  80.     if (posix_memalign(&ptr, 32, size))
              ^
  81.         ptr = NULL;
  82. #elif HAVE_ALIGNED_MALLOC

libavutil/mem.c:81:9: 
  79. #elif HAVE_POSIX_MEMALIGN
  80.     if (posix_memalign(&ptr, 32, size))
  81.         ptr = NULL;
              ^
  82. #elif HAVE_ALIGNED_MALLOC
  83.     ptr = _aligned_malloc(size, 32);

libavutil/mem.c:113:5: 
  111.     ptr = malloc(size);
  112. #endif
  113.     return ptr;
           ^
  114. }
  115. 

libavutil/mem.c:114:1: return from a call to av_malloc
  112. #endif
  113.     return ptr;
  114. }
       ^
  115. 
  116. void *av_realloc(void *ptr, size_t size)

libavformat/oggdec.c:66:5: 
64.         av_malloc(sizeof(*ost) + (ogg->nstreams - 1) * sizeof(*ogg->streams));
65.     int i;
66.     ost->pos      = avio_tell(s->pb);
        ^
67.     ost->curidx   = ogg->curidx;
68.     ost->next     = ogg->state;

libavformat/avio.h:219:1: start of procedure avio_tell()
  217.  * @return position or AVERROR.
  218.  */
  219. static av_always_inline int64_t avio_tell(AVIOContext *s)
       ^
  220. {
  221.     return avio_seek(s, 0, SEEK_CUR);

libavformat/avio.h:221:5: Skipping avio_seek(): empty list of specs
  219. static av_always_inline int64_t avio_tell(AVIOContext *s)
  220. {
  221.     return avio_seek(s, 0, SEEK_CUR);
           ^
  222. }
  223. 

libavformat/avio.h:222:1: return from a call to avio_tell
  220. {
  221.     return avio_seek(s, 0, SEEK_CUR);
  222. }
       ^
  223. 
  224. /**
