[BUG] Segmentation fault on VOB #1128
Comments
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Somehow, I suddenly can't reproduce it anymore |
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I've compiled with flag -g, runned valgrind with ==18757== 18,635,728 bytes in 1 blocks are still reachable in loss record 396 of 397 |
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I'd say that's not compiled with -g or you'd have line numbers. But nevertheless that output looks HORRIBLE. For example: That's of course asking for trouble. What value is that? We should be using memmove() in this case, IF (that's a big if) we're actually trying to move inside the buffer. The actual crash: We're calling memset over a NULL pointer. Of course it's going to crash :-) |
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Okay I've run this correctly and now I see that issue is in dvd_subtitle_decoder.c:99 So I think that I have to change memset to memmove now, is that right? |
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No, you can see there that the error is that we're memset()ing on a NULL pointer. The pointer comes from that malloc(), and the reason you're getting a NULL pointer is that you are asking for a negative amount of memory (since we knew that we had a negative height). So there's two options for now
Bonus - we should be checking the result from malloc() in any case. |
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When I've added checking if pointer is NULL: There is no longer signal 11, but it is still crashing. How to skip some block completely if the error occurs in dvd_subtitle_decoder.c but the loop's in the general_loop.c? |
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valgrind is giving you a lot of clues
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x40F693: process_data (general_loop.c:664)
What variable is used at that line and why isn't it initialized?
==6893== Source and destination overlap in memcpy(0x98681e9, 0x9868040, 2019)
==6893== at 0x4C32513: memcpy@@GLIBC_2.14 (in
/usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6893== by 0x41A3E7: process_spu (dvd_subtitle_decoder.c:380)
What's is happening there, how is that possible?
etc
…On Sun, Dec 8, 2019 at 11:58 AM Sudoxo ***@***.***> wrote:
When I've added checking if pointer is NULL:
ctx->bitmap = malloc(w*h);
buffp = ctx->bitmap;
if(!buffp)
{
dbg_print(CCX_DMT_VERBOSE, "Error!");
return;
}
memset(buffp, 0, w*h);
There is no longer signal 11, but it is still crashing.
Valgrind log after that change:
==6893== Memcheck, a memory error detector
==6893== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
==6893== Using Valgrind-3.11.0 and LibVEX; rerun with -h for copyright info
==6893== Command: ./ccextractor /home/patryk/Desktop/example.vob -debug
==6893== Parent PID: 6873
==6893==
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x40F693: process_data (general_loop.c:664)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893== Source and destination overlap in memcpy(0x98681e9, 0x9868040, 2019)
==6893== at 0x4C32513: memcpy@@GLIBC_2.14 (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6893== by 0x41A3E7: process_spu (dvd_subtitle_decoder.c:380)
==6893== by 0x40F6E1: process_data (general_loop.c:669)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x4199D3: decode_packet (dvd_subtitle_decoder.c:210)
==6893== by 0x41A554: process_spu (dvd_subtitle_decoder.c:415)
==6893== by 0x40F6E1: process_data (general_loop.c:669)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x4199DC: decode_packet (dvd_subtitle_decoder.c:210)
==6893== by 0x41A554: process_spu (dvd_subtitle_decoder.c:415)
==6893== by 0x40F6E1: process_data (general_loop.c:669)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x4199E1: decode_packet (dvd_subtitle_decoder.c:210)
==6893== by 0x41A554: process_spu (dvd_subtitle_decoder.c:415)
==6893== by 0x40F6E1: process_data (general_loop.c:669)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x4199E6: decode_packet (dvd_subtitle_decoder.c:210)
==6893== by 0x41A554: process_spu (dvd_subtitle_decoder.c:415)
==6893== by 0x40F6E1: process_data (general_loop.c:669)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893== Conditional jump or move depends on uninitialised value(s)
==6893== at 0x4199EF: decode_packet (dvd_subtitle_decoder.c:210)
==6893== by 0x41A554: process_spu (dvd_subtitle_decoder.c:415)
==6893== by 0x40F6E1: process_data (general_loop.c:669)
==6893== by 0x4105D8: general_loop (general_loop.c:1028)
==6893== by 0x407283: api_start (ccextractor.c:210)
==6893== by 0x407FB1: main (ccextractor.c:534)
==6893==
==6893==
==6893== More than 10000000 total errors detected. I'm not reporting any more.
==6893== Final error counts will be inaccurate. Go fix your program!
==6893== Rerun with --error-limit=no to disable this cutoff. Note
==6893== that errors may occur in your program without prior warning from
==6893== Valgrind, because errors are no longer being displayed.
==6893==
==6893==
==6893== HEAP SUMMARY:
==6893== in use at exit: 133,019,609 bytes in 63,684 blocks
==6893== total heap usage: 64,894,930 allocs, 64,831,246 frees, 21,781,345,659 bytes allocated
==6893==
==6893== LEAK SUMMARY:
==6893== definitely lost: 285,386 bytes in 409 blocks
==6893== indirectly lost: 0 bytes in 0 blocks
==6893== possibly lost: 2,127,644 bytes in 141 blocks
==6893== still reachable: 130,606,579 bytes in 63,134 blocks
==6893== of which reachable via heuristic:
==6893== newarray : 3,989,864 bytes in 4,344 blocks
==6893== suppressed: 0 bytes in 0 blocks
==6893== Rerun with --leak-check=full to see details of leaked memory
==6893==
==6893== For counts of detected and suppressed errors, rerun with: -v
==6893== Use --track-origins=yes to see where uninitialised values come from
==6893== ERROR SUMMARY: 10000000 errors from 7 contexts (suppressed: 0 from 0)
How to skip some block completely if the error occurs in
*dvd_subtitle_decoder.c* but the loop's in the *general_loop.c*?
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Thanks for your work on this guys - just pulled from master and rebuilt on Mac with, Then run against test file above and still getting, |
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@cfsmp3 Is this issue still active ? |
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@eshandhawan51 I'd say it is if we have a failing assert :-) |
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My commit've fixed this asset - I've successfully built on Linux. @boog said that there is an error on Mac, I don't own any Mac device so It's hard for me to make further changes. |
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@boog could you provide a backtrace? The failing assert is in tesseract code btw, so we are calling tesseract stuff wrong somewhere. |
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I tried it on macOS 10.14.5 (Tesseract 4.1.1 installed from Homebrew) with the example.vob file linked above and it worked fine, so I don't think this is an issue anymore. |
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@boog can you confirm it is fixed? |
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Closing. @boog Feel free to reopen if you are still having problems |
Please prefix your issue with one of the following: [BUG], [PROPOSAL], [QUESTION].
CCExtractor version (using the --version parameter preferably) :
CCExtractor 0.88, Carlos Fernandez Sanz, Volker Quetschke.
Teletext portions taken from Petr Kutalek's telxcc
CCExtractor detailed version info
Version: 0.88
Git commit: 280b430
Compilation date: 2019-11-27
File SHA256: eec95999b58c1a22f7a0909844d58df1e6456ae87d6c34afd782ae3ab2173c6b
Libraries used by CCExtractor
libGPAC Version: 0.7.2-DEV
zlib: 1.2.11
utf8proc Version: 2.2.0
protobuf-c Version: 1.3.1
libpng Version: 1.6.35
FreeType
libhash
nuklear
libzvbi
In raising this issue, I confirm the following (please check boxes, eg [X] - and delete unchecked ones):
My familiarity with the project is as follows (check one, eg [X] - and delete unchecked ones):
Necessary information
-debug -o test.srtVideo links (replace text below with your links)
http://ccextractor.s3-website-us-east-1.amazonaws.com/example.vob
Additional information
Ripped and decrypted from DVD with Region code 2. Sub titles are image based dvd_subtitle.
Tried to export in srt and spupng both segfault part way through. Was able to successfully extract some pngs with spupng. Debug flag doesn't output very much helpful information.
On linux:
On Mac:
PS: Make sure you set an alert in GitHub so you get notifications about your ticket. We may need to ask questions and we do everything inside GitHub's system.
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