From: Rafael Silva <rafaeloliveira.cs@gmail.com>
To: git@vger.kernel.org
Cc: "Derrick Stolee" <dstolee@microsoft.com>,
"Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>,
"Junio C Hamano" <gitster@pobox.com>,
"Eric Sunshine" <sunshine@sunshineco.com>,
"Martin Ågren" <martin.agren@gmail.com>,
"SZEDER Gábor" <szeder.dev@gmail.com>,
"Rafael Silva" <rafaeloliveira.cs@gmail.com>
Subject: [PATCH v2 0/1] maintenance: Fix SEGFAULT when running outside of a repository
Date: Thu, 26 Nov 2020 20:41:40 +0000 [thread overview]
Message-ID: <20201126204141.1438-1-rafaeloliveira.cs@gmail.com> (raw)
In-Reply-To: <20201124164405.29327-1-rafaeloliveira.cs@gmail.com>
In d7514f6ed5 (maintenance: take a lock on the objects directory, 2020-09-17) [1],
and 2fec604f8d (maintenance: add start/stop subcommands, 2020-09-11) [2] The
"git maintenance run" and "git maintenance start" was taught to hold a file-based
lock at the .git/maintenance.lock and .git/schedule.lock respectively because these
operations involves writing data into the .git/repository.
The lock file path string is built using the the_repository->objects->odb->path,
in case the_repository->objects->odb is NULL when there is not repository available,
resulting in a SEGFAULT.
In order to reproduce the error, one can execute maintenance "run" and/or
"start" subcommand with a non valid repository:
$ git -C /tmp maintenance start
Segmentation fault
$ git -C /tmp maintenance run
Segmentation fault
The above test was executed from a git built from commit: faefdd61ec (Sixth batch, 2020-11-18):
For reference here's the output from GDB when debugging the "start" command
Program received signal SIGSEGV, Segmentation fault.
0x00005555555b9b4c in maintenance_run_tasks (opts=0x7fffffffded4) at builtin/gc.c:1268
1268 char *lock_path = xstrfmt("%s/maintenance", r->objects->odb->path);
Updates in v2
=============
* Instead of implementing the check on the subcommands, a more robust approach
is taken by replacing the "maintenance" command option to use RUN_SETUP
instead of RUN_SETUP_GENTLY as suggested by Derrick Stolee in [3] as part of
review cycle from v1.
This provides protection for all maintenance subcommands given that
currently all the commands are required to be executed inside a repository.
* As the RUN_SETUP will enable protection to all commands, the checks in
maintenance_register() and maintenance_unregister() are removed as they
are not required anymore.
* Use the "nongit" helper function for testing it instead of relying on the
`/tmp` directory for a non valid git repository as suggested by
SZEDER Gábor and Eric Sunshine in [4].
* All "git maintenance" subcommands are included on the test to ensure the
behaviour is consistent for all subcommands. In particular the "register"
command that current exists without a message and code 0 which will be
changed by this patch to fail when running outside of a repository.
It also worth noting that "register" command does not exists in a released
version of Git as mentioned in [5] which make it easier for changing the
current behaviour of the command
[1] https://lore.kernel.org/git/1a0a3eebb825ac3eabfdd86f82ed7ef6abb454c5.1600366313.git.gitgitgadget@gmail.com/
[2] https://lore.kernel.org/git/5194f6b1facbd14cc17eea0337c0cc397a2a51fc.1602782524.git.gitgitgadget@gmail.com/
[3] https://lore.kernel.org/git/1bfd84da-5b74-be10-fc2c-dee80111ee2d@gmail.com/
[4] https://lore.kernel.org/git/20201124191407.GC8396@szeder.dev/
[5] https://lore.kernel.org/git/54fa678c-7150-8c48-50e5-b33923a69249@gmail.com/
Thanks everyone for the insightful and helpful feedback.
Rafael Silva (1):
maintenance: fix SEGFAULT when no repository
builtin/gc.c | 7 -------
git.c | 2 +-
t/t7900-maintenance.sh | 8 ++++++++
3 files changed, 9 insertions(+), 8 deletions(-)
--
2.29.2.367.g37477fb670
next prev parent reply other threads:[~2020-11-26 20:53 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 16:44 [PATCH 0/1] maintenance: Fix a SEGFAULT when no repository when running git maintenance run/start Rafael Silva
2020-11-24 16:44 ` [PATCH 1/1] maintenance: fix a SEGFAULT when no repository Rafael Silva
2020-11-24 17:22 ` Derrick Stolee
2020-11-24 21:48 ` Junio C Hamano
2020-11-24 21:59 ` Derrick Stolee
2020-11-26 8:22 ` Rafael Silva
2020-11-26 11:21 ` Derrick Stolee
2020-11-24 17:24 ` Eric Sunshine
2020-11-24 19:14 ` SZEDER Gábor
2020-11-24 19:34 ` Eric Sunshine
2020-11-26 7:13 ` Rafael Silva
2020-11-24 19:03 ` Martin Ågren
2020-11-26 7:07 ` Rafael Silva
2020-11-26 20:41 ` Rafael Silva [this message]
2020-11-26 20:41 ` [PATCH v2 1/1] maintenance: fix " Rafael Silva
2020-11-27 20:43 ` Derrick Stolee
2020-12-08 20:12 ` Josh Steadmon
2020-12-08 21:58 ` Junio C Hamano
2020-12-08 22:17 ` Junio C Hamano
2020-12-24 8:12 ` Christian Couder
2020-12-24 14:14 ` Junio C Hamano
2020-12-09 9:29 ` Rafael Silva
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