Date: Wed, 4 Jun 2008 21:53:57 +0200 From: Ed Schouten <ed@80386.nl> To: Peter Jeremy <peterjeremy@optushome.com.au> Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>, Chuck Robey <chuckr@telenix.org> Subject: Re: git problems Message-ID: <20080604195357.GD1176@hoeg.nl> In-Reply-To: <20080604191137.GC1028@server.vk2pj.dyndns.org> References: <4845AC84.6040407@telenix.org> <TbQi51CAu4j4cFDkKULTI53ON0k@8ZdGo3QYE5K669Y/W2Z6ZKf2XtY> <4846A77B.9060603@telenix.org> <L4F%2B2AmHcL4Uix8Rch4QiSpqQwc@RzJPyOBFuChtvuf1tf1krA3%2BwkI> <4846B40A.4010309@telenix.org> <20080604191137.GC1028@server.vk2pj.dyndns.org>
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--veXX9dWIonWZEC6h Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable * Peter Jeremy <peterjeremy@optushome.com.au> wrote: > On 2008-Jun-04 11:26:02 -0400, Chuck Robey <chuckr@telenix.org> wrote: > >#3 0x08066467 in unlock_pack () at builtin-fetch.c:56 > >#4 0x2848b5f3 in __cxa_finalize () from /lib/libc.so.7 > >#5 0x2843b1aa in exit () from /lib/libc.so.7 > >#6 0x0804b0e3 in handle_internal_command (argc=3D2, argv=3D0xffffffff) = at git.c:379 > >#7 0x0804b7ed in main (argc=3D2, argv=3DCannot access memory at address= 0x12) at git.c:414 >=20 > __cxa_finalise() is part of the atexit() processing - the source comments > imply it handles shared object destructors. >=20 > >379 exit(run_command(p, argc, argv)); > >380 } > > > >First I want to comment on that weird line 379, because while it > >might work, it sure seems to me to be a very strange and wasteful way > >to do a fork. >=20 > There's no fork involved. It's just shorthand for: > return_code =3D run_command(p, argc, argv); > exit(return_code); > By the time exit() is invoked, run_command() has completed. >=20 > > Second, the second argument to handle_internal_command seems to > >have been a argv=3D0xffffffff, which is very obviously a bad string > >pointer >=20 > Note that argv in main is also corrupt. I suspect gdb is confused by > the level of optimisation being done by gcc. >=20 > In a later posting, you indicate that there's a double-free bug. > Possibly unlock_pack() is being registered as a destructor (or > similar) _and_ is being explicitly called. Without studying the > code, the solution is probably to either skip the explicit cleanup > (leaving just the destructor processing) and/or flag freed data (ie > NULL pointers after freeing them). I just solved this on my systems by removing the call to free(). I know, it's awful, but it was good enough for me to live with on short term. --=20 Ed Schouten <ed@80386.nl> WWW: http://80386.nl/ --veXX9dWIonWZEC6h Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkhG8tUACgkQ52SDGA2eCwWWqwCfWyeNg9NWoU7PZGJ9w4//aU5v 5NAAn0O4MRYjFZFv3lY5dvF2OmKMXC6v =7ivG -----END PGP SIGNATURE----- --veXX9dWIonWZEC6h--
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