git-update-server-info crashes on hera.kernel.org:/pub/scm/libs/klibc/klibc.git

git-core-0.99.9j-1, and the backtrace is as follows:

: hera 29 ; ls -l /usr/lib/debug/usr/bin/git-update-
git-update-index.debug* git-update-ref.debug* git-update-server-info.debug*
: hera 29 ; gdb -s /usr/lib/debug/usr/bin/git-update-server-info.debug /usr/bin/git-update-server-info GNU gdb Red Hat Linux (6.3.0.0-1.63rh)
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This GDB was configured as "i386-redhat-linux-gnu"...Using host libthread_db library "/lib/tls/libthread_db.so.1".

(gdb) run
Starting program: /usr/bin/git-update-server-info

Program received signal SIGSEGV, Segmentation fault.
0x0804c04c in nth_packed_object_sha1 (p=0x986a1f0, n=0, sha1=0xbfffc9f0 "") at sha1_file.c:1017
1017 memcpy(sha1, (index + 24 * n + 4), 20);
(gdb) where

#0  0x0804c04c in nth_packed_object_sha1 (p=0x986a1f0, n=0, sha1=0xbfffc9f0 "") at sha1_file.c:1017
#1  0x08049a61 in update_server_info (force=0) at server-info.c:248
#2  0x08049466 in main (ac=1, av=0xbfffeed4) at update-server-info.c:22
#3  0x00ce1e23 in __libc_start_main () from /lib/tls/libc.so.6
#4  0x080493a1 in _start ()

-hpa

I made a copy of that repository on hera and tried it but cannot reproduce (with or without -f flag -- and running under gdb with symbols did not make difference either). Sorry, I am baffled. The same machine, the same set of input and binary.

junio@hera:~/t(0)$ echo $PATH
/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin
junio@hera:~/t(0)$ (cd /pub/scm/libs/klibc/ && tar cf - klibc.git ) | tar xf -
junio@hera:~/t(0)$ head -n 4 klibc.git/objects/info/packs
P pack-122eb314270865bdaaded7d02c7340014537abbf.pack
D 0
T 0 005146812e1e36309409128e0bbaf86e6745a637 tag
T 0 00aea41acad6d139679416a79ff9139a50b5001c tag
junio@hera:~/t(0)$ GIT_DIR=klibc.git /usr/bin/git-update-server-info ; echo $?
0
junio@hera:~/t(0)$ head -n 4 klibc.git/objects/info/packs
P pack-1433c87e76496ad3f628652c0cb81d288c178fc5.pack
P pack-f9db0b232716d835858232fbecfb410d22ae5afb.pack
D 0
junio@hera:~/t(0)$ rm -fr klibc.git
junio@hera:~/t(0)$ (cd /pub/scm/libs/klibc/ && tar cf - klibc.git ) | tar xf -  junio@hera:~/t(0)$ head -n 4 klibc.git/objects/info/packs
P pack-122eb314270865bdaaded7d02c7340014537abbf.pack
D 0
T 0 005146812e1e36309409128e0bbaf86e6745a637 tag
T 0 00aea41acad6d139679416a79ff9139a50b5001c tag
junio@hera:~/t(0)$ GIT_DIR=klibc.git /usr/bin/git-update-server-info -f; echo $?
0
junio@hera:~/t(0)$ head -n 4 klibc.git/objects/info/packs
P pack-122eb314270865bdaaded7d02c7340014537abbf.pack
P pack-1433c87e76496ad3f628652c0cb81d288c178fc5.pack
P pack-f9db0b232716d835858232fbecfb410d22ae5afb.pack
D 0
junio@hera:~/t(0)$ exit

FWIW, I invoked this as:

hpa@hera:~(0)$ GIT_DIR=/pub/scm/libs/klibc/klibc.git git-update-server-info
Segmentation fault

-hpa

Trusting that I *won't* be able to write into that repository, I tried to run that and after getting an error ("cannot update info/refs file", which I wanted to see) I seem to be getting the same segfault. GDB session reveals the binary is heavily optimized or inlined, so it is hard to see what it is doing though.

But there is one thing that is mysterious about your repository, and by mirroring that peculiarity with the copy in my home directory, I managed to reproduce the problem with my copy. Why does the objects/info/alternates in that repository point at itself? I suspect if you remove that file you will be OK.

update-server-info simply dying, instead of complaining about it, is a bug nevertheless, and removal of the unnecessary/possibly wrong alternate is only a workaround, but I hope that would unblock you in the meantime..

Removing that file did indeed work. I have no idea where it comes from, though; although I would guess it comes from another repository that I merged with (which had my original repository set as an alternate.)

-hpa