Hi,
I am trying to use Tesseract in a multi-threaded Android application, where
we actually would like to OCR multiple separate lines of text in parallel.
However, from time to time the application crashes due to an invalid call
to free (4 examples below).
This happens interestingly only on a low-end Android-4.4 device, the
Android-5 device I also use for development runs the code fine (however, it
has three times the memory).
Here is how I use Tesseract:
- At startup 4 instances of TessBaseAPI are instantiated, as well as a
ThreadPoolExecutor with 4 threads
- When processing, 4 separate lines of text are processed, where each
TessBaseAPI processes a single line on a separate Thread:
public void run() {
baseApi.setImage(bitmap);
baseApi.getUTF8Text();
}
Here is what I've tried so far:
- Ran all other native code (without tesseract) under valgrind to make sure
something else is not corrupting the heap - zero errors are reported
- Made sure a TessBaseAPI-Instance isn't used by multiple threads
concurrently
Any further ideas what I could try to track this issue down?
Thank you in advance, Clemens
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea44 400b0d5d
/system/lib/libc.so (free+12)
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea4c 5f53da6b
/data/app-lib/com.example.cam-1/libtess.so (TWERD::Clear()+60)
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea5c 5f548457
/data/app-lib/com.example.cam-1/libtess.so (TWERD::~TWERD()+8)
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea64 5f54849b
/data/app-lib/com.example.cam-1/libtess.so (WERD_RES::ClearResults()+58)
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea6c 5f548afd
/data/app-lib/com.example.cam-1/libtess.so (WERD_RES_zapper(ELIST_LINK*))
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea74 5f548aa5
/data/app-lib/com.example.cam-1/libtess.so (WERD_RES::~WERD_RES()+8)
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea7c 5f548b07
/data/app-lib/com.example.cam-1/libtess.so (WERD_RES_zapper(ELIST_LINK*)+10)
08-25 17:26:34.049 226-226/? I/DEBUG﹕ 6286ea84 5f5533a1
/data/app-lib/com.example.cam-1/libtess.so (ELIST::internal_clear(void
(*)(ELIST_LINK*))+24)
08-25 17:14:32.999 226-226/? I/DEBUG﹕ #08 pc 0000dd5b
/system/lib/libc.so (free+10)
08-25 17:14:32.999 226-226/? I/DEBUG﹕ #09 pc 000b839f
/data/app-lib/com.example.cam-1/libtess.so (ELIST::internal_clear(void
(*)(ELIST_LINK*))+22)
08-25 17:14:32.999 226-226/? I/DEBUG﹕ #10 pc 000acb0d
/data/app-lib/com.example.cam-1/libtess.so
(GENERIC_2D_ARRAY<BLOB_CHOICE_LIST*>::delete_matrix_pointers()+40)
08-25 16:53:14.709 226-226/? I/DEBUG﹕ 6209993c 400b0d5d
/system/lib/libc.so (free+12)
08-25 16:53:14.709 226-226/? I/DEBUG﹕ 62099940 5f671450
/data/app-lib/com.example.cam-2/libtess.so
08-25 16:53:14.709 226-226/? I/DEBUG﹕ 62099944 5f52963b
/data/app-lib/com.example.cam-2/libtess.so
(_TessFunctionResultCallback_0_2<false, bool, int const&, int
const&>::~_TessFunctionResultCallback_0_2()+18)
08-25 16:53:14.709 226-226/? I/DEBUG﹕ 62099948 6209996c [stack:23160]
08-25 16:53:14.709 226-226/? I/DEBUG﹕ 6209994c 5f5128ef
/data/app-lib/com.example.cam-2/libtess.so (GenericVector<int>::clear()+82)
08-25 13:27:54.401 226-226/? I/DEBUG﹕ #00 pc 000118bc
/system/lib/libc.so (dlfree+1191)
08-25 13:27:54.401 226-226/? I/DEBUG﹕ #01 pc 0000dd5b
/system/lib/libc.so (free+10)
08-25 13:27:54.401 226-226/? I/DEBUG﹕ #02 pc 000b839f
/data/app-lib/com.example.cam-2/libtess.so (ELIST::internal_clear(void
(*)(ELIST_LINK*))+22)
08-25 13:27:54.401 226-226/? I/DEBUG﹕ #03 pc 000acb0d
/data/app-lib/com.example.cam-2/libtess.so
(GENERIC_2D_ARRAY<BLOB_CHOICE_LIST*>::delete_matrix_pointers()+40)
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