Re: Error converting from 1.4.4.1 to 1.5.0?

On Wednesday, February 14, 2007 at 10:19:53 (-0800) Linus Torvalds writes:

On Wed, 14 Feb 2007, Bill Lear wrote:

quoted

fatal: failed to find delta-pack base object 90bad0d280a6d7c155bbd9582b35ffcf5e3bdd27

implies that the pack really is corrupt.
...
  (b) it might be interesting for others (if you can make those 
      pack-files available) to try to figure out what exactly the 
      corruption was. We've done it before, when it turned out to be a 
      single-bit error.

If you could tell me who I should contact about this, I will.

- if you have other git archives or just back-ups of everything, just use 
  them, and throw the corrupt one away entirely (but see above on why 
  it's nice to have an archive of the corruption for posterity anyway)

I would prefer to help straighten this out --- I have a company repo
to fall back on, I have git 1.4 and other repos to fall back on, so
I'm safe.

- if you don't, you can try "git unpack-objects -r". See the man-page on 
  why you need to first _move_ the pack-file away:

mv <bad-pack-file> .git/bad-pack.pack
mv <bad-pack-index> .git/bad-index.index

git unpack-objects -r < .git/bad-pack.pack

Since I can reproduce the error fairly readily, I can do this later.

Finally: it would be very interesting to hear if you do something strange 
or unusual that could have made your chances of getting corruption higher.

Have you ever seen random SIGSEV's or strange oopses, which could be a 
sign of memory corruption on your machine? Do you do a lot of things over 
NFS? (which really can corrupt things, especially in circumstances with 
dodgy ethernet chips: the UDP checksums are very weak, and some ethernet 
cards do not do a good job of checking the ethernet CRC's!).

No NFS, but I checked /var/log/messages.  I see segfaults from git,
that I missed somehow (don't remember seeing anything awry on the
terminal):

Feb 14 10:05:07 lisa kernel: git[21648]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc158 error 4
Feb 14 10:05:43 lisa kernel: git[21710]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc158 error 4
Feb 14 10:06:28 lisa kernel: git[21858]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc158 error 4
Feb 14 10:10:04 lisa kernel: git[22385]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc158 error 4
Feb 14 11:01:56 lisa kernel: git[24446]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc888 error 4
Feb 14 11:02:34 lisa kernel: git[24479]: segfault at 0000000000000000 rip 0000003f5eb70a40 rsp 0000007fbfffc868 error 4
Feb 14 11:02:40 lisa kernel: git[24700]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc868 error 4
Feb 14 11:07:51 lisa kernel: git[24844]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc128 error 4
Feb 14 11:07:52 lisa kernel: git[24855]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc128 error 4
Feb 14 11:08:01 lisa kernel: git[24886]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc128 error 4
Feb 14 11:08:06 lisa kernel: git[24897]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc118 error 4
Feb 14 11:08:09 lisa kernel: git[24908]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc118 error 4
Feb 14 11:08:27 lisa kernel: git[24939]: segfault at 0000000000000000 rip 0000003f5eb709d0 rsp 0000007fbfffc158 error 4

10:05 is just before I posted my first note of this to the git list, and
the first instance of a segfault that I see.

And if you can make the git history available to outsiders, I'd love to 
see the corrupt tar-file (it doesn't have to be *public*, if you just can 
trust me and perhaps a few other people with the data).

Again, please let me know who to contact about helping on this.


Bill