Great! Thank you all guys for your extensive instructions! @Thomas: I only had to add libexpat1-dev to the list. I checked out Git v1.8.3.4 as this was my used verion and built as instructed. The error is still reproducible using the "CFLAGS = -O0 -g" build. So - now the puzzling thing: With valgrind it seems to work! If I run it plain, it doesn't: /tmp/project.git $ valgrind --track-origins=yes ~/projects/git.git/git-fsck ==3431== Memcheck, a memory error detector ==3431== Copyright (C) 2002-2011, and GNU GPL'd, by Julian Seward et al. ==3431== Using Valgrind-3.7.0 and LibVEX; rerun with -h for copyright info ==3431== Command: /home/ben/projects/git.git/git-fsck ==3431== ==3431== Warning: set address range perms: large range [0x70b5000, 0x2b0ff000) (defined) Checking object directories: 100% (256/256), done. ==3431== Warning: set address range perms: large range [0x3959d000, 0x49d53000) (defined) Checking objects: 100% (63588/63588), done. Checking connectivity: 68696, done. ==3431== ==3431== HEAP SUMMARY: ==3431== in use at exit: 7,574,911 bytes in 15,428 blocks ==3431== total heap usage: 422,498 allocs, 407,070 frees, 4,396,939,465 bytes allocated ==3431== ==3431== LEAK SUMMARY: ==3431== definitely lost: 0 bytes in 0 blocks ==3431== indirectly lost: 0 bytes in 0 blocks ==3431== possibly lost: 0 bytes in 0 blocks ==3431== still reachable: 7,574,911 bytes in 15,428 blocks ==3431== suppressed: 0 bytes in 0 blocks ==3431== Rerun with --leak-check=full to see details of leaked memory ==3431== ==3431== For counts of detected and suppressed errors, rerun with: -v ==3431== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2) /tmp/project.git $ ~/projects/git.git/git-fsck Checking object directories: 100% (256/256), done. error: packed 49cdd0b21a351f3366008615d2cf8d03ca943978 from .git/objects/pack/pack-6a6f5355584a5d71215d5fc867ce09602ceab533.pack is corrupt *** glibc detected *** <unknown>: free(): invalid pointer: 0x00007f8576682010 *** ======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(+0x7eb96)[0x7f85ad765b96] [0x4e727c] I'm using a i5-3340M on Linux Mint 14 with a offical Linux 3.9.9 gcc (Ubuntu/Linaro 4.7.2-2ubuntu1) 4.7.2 Any further hints? > Try something like > > # The package names might be wrong and/or you may need additional -dev > # packages, I don't know the specifics for ubuntu > apt-get install gcc make valgrind libcurl-dev zlib-dev > cd > git clone git://git.kernel.org/pub/scm/git/git.git > cd git > echo 'CFLAGS = -O0 -g' >>config.mak > make > cd /path/to/repo > valgrind --track-origins=yes ~/git/git-fsck > > It'll be very slow, at least 20x the normal runtime, so don't be > surprised if it doesn't seem to get anywhere at first. > -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html