[FFmpeg-trac] #8292(undetermined:new): outside the range of representable values of type 'unsigned char' at libavfilter/vf_gblur.c:326

FFmpeg trac at avcodec.org
Wed Oct 16 19:59:40 EEST 2019


#8292: outside the range of representable values of type 'unsigned char'  at
libavfilter/vf_gblur.c:326
-------------------------------------+-------------------------------------
             Reporter:  Suhwan       |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:  git-
  undetermined                       |  master
             Keywords:  ubsan        |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 There is an outside the range of representable values of type 'unsigned
 char'  at libavfilter/vf_gblur.c:326

 I compiled ffmpeg with "--toolchain=clang-usan" to check the undefined-
 behaviours and attached log file.
 How to reproduce:
 {{{
 % ffmpeg_g -t 1 -stream_loop 25 -y -i $PoC -filter_complex gblur -target
 dv50 -loglevel 0 tmp.acm

 ffmpeg version N-95405-g98ae6b0a4d Copyright (c) 2000-2019 the FFmpeg
 developers
 built with clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
 configuration: --cc=clang --cxx=clang++ --ld=clang --enable-debug
 --toolchain=clang-usan
 }}}

 Here's UBSAN log

 {{{
 libavfilter/vf_gblur.c:326:30: runtime error: 258.787 is outside the range
 of representable values of type 'unsigned char'

 Thread 1 "ffmpeg_g" hit Breakpoint 1, 0x00000000004288b0 in
 __ubsan::ScopedReport::~ScopedReport() ()
 (gdb) bt
 #0  0x00000000004288b0 in __ubsan::ScopedReport::~ScopedReport() ()
 #1  0x000000000042a4e6 in handleFloatCastOverflow(void*, unsigned long,
 __ubsan::ReportOptions) ()
 #2  0x000000000042cd11 in __ubsan_handle_float_cast_overflow ()
 #3  0x00000000009e17fb in filter_frame (inlink=<optimized out>,
 in=<optimized out>) at libavfilter/vf_gblur.c:326
 #4  0x00000000005cfe9d in ff_filter_frame_framed (link=<optimized out>,
 frame=0x0) at libavfilter/avfilter.c:1084
 #5  ff_filter_frame_to_filter (link=<optimized out>) at
 libavfilter/avfilter.c:1232
 #6  ff_filter_activate_default (filter=<optimized out>) at
 libavfilter/avfilter.c:1281
 #7  ff_filter_activate (filter=<optimized out>) at
 libavfilter/avfilter.c:1443
 #8  0x00000000005f42bf in push_frame (graph=0x93cc340) at
 libavfilter/buffersrc.c:187
 #9  av_buffersrc_add_frame_internal (ctx=<optimized out>, frame=0x93cb7c0,
 flags=<optimized out>) at libavfilter/buffersrc.c:261
 #10 0x00000000005f2e7e in av_buffersrc_add_frame_flags (ctx=0x93d1440,
 frame=0x93cb7c0, flags=4) at libavfilter/buffersrc.c:170
 #11 0x00000000004cad60 in ifilter_send_frame (ifilter=<optimized out>,
 frame=<optimized out>) at fftools/ffmpeg.c:2186
 #12 send_frame_to_filters (ist=0x93b3140, decoded_frame=0x93cb7c0) at
 fftools/ffmpeg.c:2260
 #13 0x00000000004a07bc in decode_video (ist=<optimized out>,
 pkt=<optimized out>, got_output=<optimized out>, duration_pts=<optimized
 out>, eof=<optimized out>, decode_failed=<optimized out>)
     at fftools/ffmpeg.c:2459
 #14 process_input_packet (ist=<optimized out>, pkt=<optimized out>,
 no_eof=<optimized out>) at fftools/ffmpeg.c:2613
 #15 0x00000000004bf0f0 in process_input (file_index=<optimized out>) at
 fftools/ffmpeg.c:4508
 #16 0x000000000048d5eb in transcode_step () at fftools/ffmpeg.c:4628
 #17 transcode () at fftools/ffmpeg.c:4682
 #18 0x0000000000487da4 in main (argc=15, argv=<optimized out>) at
 fftools/ffmpeg.c:4884

 }}}
 Please confirm.
 Thanks

--
Ticket URL: <https://trac.ffmpeg.org/ticket/8292>
FFmpeg <https://ffmpeg.org>
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