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The usual entry point for loading the pack revindex is the
load_pack_revindex() function. It returns immediately if the packed_git
has a non-NULL revindex or revindex data field (representing an
in-memory or mmap'd .rev file, respectively), since the data is already
loaded.
But in 5a6072f631 (fsck: validate .rev file header, 2023-04-17) the fsck
code path switched to calling load_pack_revindex_from_disk() directly,
since it wants to check the on-disk data (if there is any). But that
function does _not_ check to see if the data has already been loaded; it
just maps the file, overwriting the revindex_map pointer (and pointing
revindex_data inside that map). And in that case we've leaked the mmap()
pointed to by revindex_map (if it was non-NULL).
This usually doesn't happen, since fsck wouldn't need to load the
revindex for any reason before we get to these checks. But there are
some cases where it does. For example, is_promisor_object() runs
odb_for_each_object() with the PACK_ORDER flag, which uses the revindex.
This happens a few times in our test suite, but SANITIZE=leak doesn't
detect it because we are leaking an mmap(), not a heap-allocated buffer
from malloc(). However, if you build with NO_MMAP, then our compat mmap
will read into a heap buffer instead, and LSan will complain. This
causes failures in t5601, t0410, t5702, and t5616.
We can fix it by checking for existing revindex_data when loading from
disk. This is redundant when we're called from load_pack_revindex(), but
it's a cheap check. The alternative is to teach check_pack_rev_indexes()
in fsck to skip the load, but that seems messier; it doesn't otherwise
know about internals like revindex_map and revindex_data.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an unusually rich command set that provides both high-level operations and full access to internals.
Git is an Open Source project covered by the GNU General Public License version 2 (some parts of it are under different licenses, compatible with the GPLv2). It was originally written by Linus Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/ including full documentation and Git related tools.
See Documentation/gittutorial.adoc to get started, then see
Documentation/giteveryday.adoc for a useful minimum set of commands, and
Documentation/git-<commandname>.adoc for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.adoc
(man gitcvs-migration or git help cvs-migration if git is
installed).
The user discussion and development of Git take place on the Git mailing list -- everyone is welcome to post bug reports, feature requests, comments and patches to git@vger.kernel.org (read Documentation/SubmittingPatches for instructions on patch submission and Documentation/CodingGuidelines).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
To subscribe to the list, send an email to git+subscribe@vger.kernel.org (see https://subspace.kernel.org/subscribing.html for details). The mailing list archives are available at https://lore.kernel.org/git/, https://marc.info/?l=git and other archival sites.
Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that list the current status of various development topics to the mailing list. The discussion following them give a good reference for project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood):
- random three-letter combination that is pronounceable, and not actually used by any common UNIX command. The fact that it is a mispronunciation of "get" may or may not be relevant.
- stupid. contemptible and despicable. simple. Take your pick from the dictionary of slang.
- "global information tracker": you're in a good mood, and it actually works for you. Angels sing, and a light suddenly fills the room.
- "goddamn idiotic truckload of sh*t": when it breaks