Do not use zlib 1.1.3 with git packs!

Hi,

I had a strange effect when trying to repack a git repository on my iBook: first, "git-repack -a -d" would quit without an error message when about 57% of the objects were written (*not* when deltifying them!).

It became even stranger when I tracked it to a segmentation fault in adler32(), where the debugger insisted that a buffer was NULL, but the calling code insisted it was not.

Upgrading to zlib 1.2.3 helped. That is, after I had a complete systen fsck-up, since virtually every binary, including su, login and getty, are linked to zlib on Mac OS X. (Yeah, yeah, no Linux, I know.)

Ciao, Dscho

P.S.: This _might_ be related to the git-repack issue that came up a few days ago.

Hi,

On Sat, 29 Apr 2006, Johannes Schindelin wrote:

Apparently I was too enthusiastic to have a working system again.

The problem showed again, but with a different repository.

This time, though, I have an idea what could be the culprit.

In create_delta(), there might be illegal accesses. The function adler32() is called for BLK_SIZE bytes (which is 16 bytes at the moment), starting from data, which is initially trg_buf, and is incremented until it is (trg_buf + trg_size).

I gather that close to the end, adler32() tries to read 15 bytes after the end of the allocated target buffer.

Am I wrong?

Ciao, Dscho

On Sat, 29 Apr 2006, Johannes Schindelin wrote:

You're not.  My bad.

(I'm testing a version where adler32 has been replaced with rabin 
 polynomial so that issue will be gone at the same time.
 A patch should be coming in less than an hour.)

Nicolas

Nicolas Pitre <nico@cam.org> writes:

Thanks both, for catching this while still in "next".