> 2021年12月3日 下午5:42,Andreas Rheinhardt <andreas.rheinha...@outlook.com> 写道: > > Yu Yang: >> Opts is assigned by setup_find_stream_info_opts(). Opts may be NULL. >> This situation is compatible in avformat_find_stream_info(). >> Before av_dict_free(), the necessary checks were ignored. >> >> // in fftools/ffmpeg_opt.c:1266 >> 1067 static int open_input_file(OptionsContext *o, const char *filename) >> 1068 { >> ... >> 1191 AVDictionary **opts = setup_find_stream_info_opts(ic, >> o->g->codec_opts); >> ... >> 1196 ret = avformat_find_stream_info(ic, opts); >> 1197 >> 1198 for (i = 0; i < orig_nb_streams; i++) >> 1199 av_dict_free(&opts[i]); >> ... >> 1342 } >> ``` >> ```c >> // in libavutil/dict.c:203 >> 203 void av_dict_free(AVDictionary **pm) >> 204 { >> 205 AVDictionary *m = *pm; >> ... >> 215 } >> >> coredump backtrace info: >> ==6235==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc >> 0x000006ba9c2f bp 0x7ffc3d5baa30 sp 0x7ffc3d5ba9a0 T0) >> ==6235==The signal is caused by a READ memory access. >> ==6235==Hint: address points to the zero page. >> #0 0x6ba9c2f in av_dict_free >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/dict.c:205:23 >> #1 0x4ce5ac in open_input_file >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg_opt.c:1199:13 >> #2 0x4c9dc0 in open_files >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg_opt.c:3338:15 >> #3 0x4c9295 in ffmpeg_parse_options >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg_opt.c:3378:11 >> #4 0x58f241 in main >> /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4988:11 >> #5 0x7fe35197f0b2 in __libc_start_main >> /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16 >> #6 0x42033d in _start (/home/r1/ffmpeg/ffmpeg_4.4.1+0x42033d) >> >> Reported-by: TOTE Robot <os...@tsinghua.edu.cn> >> Signed-off-by: Yu Yang <young_chel...@163.com> >> --- >> fftools/ffmpeg_opt.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/fftools/ffmpeg_opt.c b/fftools/ffmpeg_opt.c >> index a27263b879..a9fc54d948 100644 >> --- a/fftools/ffmpeg_opt.c >> +++ b/fftools/ffmpeg_opt.c >> @@ -1197,10 +1197,11 @@ static int open_input_file(OptionsContext *o, const >> char *filename) >> /* If not enough info to get the stream parameters, we decode the >> first frames to get it. (used in mpeg case for example) */ >> ret = avformat_find_stream_info(ic, opts); >> - >> - for (i = 0; i < orig_nb_streams; i++) >> - av_dict_free(&opts[i]); >> - av_freep(&opts); >> + if (opts){ >> + for (i = 0; i < orig_nb_streams; i++) >> + av_dict_free(&opts[i]); >> + av_freep(&opts); >> + } >> >> if (ret < 0) { >> av_log(NULL, AV_LOG_FATAL, "%s: could not find codec >> parameters\n", filename); >> > > You should instead check setup_find_stream_info_opts() (either only call > it if orig_nb_streams is > 0 or modify it to return an error code given > that it can currently return NULL even on nonerror). Thanks for your advice, i will try to fix it again. > > - Andreas > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
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