252d693797
For a long time we have used ASAN_OPTIONS to set abort_on_error. This is important because we want to notice detected problems even in programs which are expected to fail. But we never did the same for UBSAN_OPTIONS. This means that our UBSan test suite runs might silently miss some cases. It also causes a more visible effect, which is that t4058 complains about unexpected "fixes" (and this is how I noticed the issue): $ make SANITIZE=undefined CC=gcc && (cd t && ./t4058-*) ... ok 8 - git read-tree does not segfault # TODO known breakage vanished ok 9 - reset --hard does not segfault # TODO known breakage vanished ok 10 - git diff HEAD does not segfault # TODO known breakage vanished The tests themselves aren't that interesting. We have a known bug where these programs segfault, and they do when compiled without sanitizers. With UBSan, when the test runs: test_might_fail git read-tree --reset base it gets: cache-tree.c:935:9: runtime error: member access within misaligned address 0x5a5a5a5a5a5a5a5a for type 'struct cache_entry', which requires 8 byte alignment So that's garbage memory which would _usually_ cause us to segfault, but UBSan catches it and complains first about the alignment. That makes sense, but the weird thing is that UBSan then exits instead of aborting, so our test_might_fail call considers that an acceptable outcome and the test "passes". Curiously, this historically seems to have aborted, because I've run "make test" with UBSan many times (and so did our CI) and we never saw the problem. Even more curiously, I see an abort if I use clang with ASan and UBSan together, like: # this aborts! make SANITIZE=undefined,address CC=clang But not with just UBSan, and not with both when used with gcc: # none of these do make SANITIZE=undefined CC=gcc make SANITIZE=undefined CC=clang make SANITIZE=undefined,address CC=gcc Likewise moving to older versions of gcc (I tried gcc-11 and gcc-12 on my Debian system) doesn't abort. Nor does moving around in Git's history. Neither this test nor the relevant code have been touched in a while, and going back to v2.41.0 produces the same outcome (even though many UBSan CI runs have passed in the meantime). So _something_ changed on my system (and likely will soon on other people's, since this is stock Debian unstable), but I didn't track it further. I don't know why it ever aborted in the past, but we definitely should be explicit here and tell UBSan what we want to happen. 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.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt 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.txt
(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 with just "subscribe git" in the body to majordomo@vger.kernel.org (not the Git list). The mailing list archives are available at https://lore.kernel.org/git/, http://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