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From: Jeff King <peff@peff•net>
To: Patrick Steinhardt <ps@pks•im>
Cc: git@vger•kernel.org
Subject: Re: [PATCH 0/2] Plug two memory leaks exposed via Meson
Date: Wed, 29 Jan 2025 15:05:09 -0500	[thread overview]
Message-ID: <20250129200509.GA2331283@coredump.intra.peff.net> (raw)
In-Reply-To: <20250129-b4-pks-memory-leaks-v1-0-79e41299eb0c@pks.im>

On Wed, Jan 29, 2025 at 05:24:13PM +0100, Patrick Steinhardt wrote:

> I've had the need to play around with the memory leak sanitizer today
> and for the first time used it with Meson. Interestingly enough, a test
> run with Meson flags two memory leaks that our Makefile doesn't. I
> haven't found the time yet to figure out why that is, but this small
> patch series fixes both of these leaks.

At least for the first one, it depends on how long the path to your
trash directory is. Doing this:

  make SANITIZE=leak
  cd t
  ./t0301-credential-cache.sh --root=/tmp/this_is_a_very_long_path/the_size_of_sockaddr_un_sun_path_is_usually_108

will fail reliably (it's not 108, but with the trash directory and xdg
boilerplate tacked on, it is).  The failed chdir() triggers because it's
trying the xdg path to see if it exists.

With "make", my path is something like:

  /home/peff/compile/git/t/trash directory.t0301-credential-cache/.cache/git/credential/socket

which is 93 bytes. If I do an out-of-tree build into the "build"
directory, then I get 109 bytes, one too many:

  /home/peff/compile/git/build/test-output/trash directory.t0301-credential-cache/.cache/git/credential/socket

so it is mostly a matter of luck combined with your personal directory
layout.

This test would trigger it reliably, but it's weirdly specific:

diff --git a/t/t0301-credential-cache.sh b/t/t0301-credential-cache.sh
index dc30289f75..0ef8ce4e60 100755
--- a/t/t0301-credential-cache.sh
+++ b/t/t0301-credential-cache.sh
@@ -134,6 +134,13 @@ test_expect_success SYMLINKS 'use user socket if user directory is a symlink to
 	test_path_is_socket "$HOME/.git-credential-cache/socket"
 '
 
+test_expect_success 'error path for chdir of long socket name' '
+	A=aaaaaaaaaaaaaaaa &&
+	LONG=$A/$A/$A/$A/$A/$A/$A/$A &&
+	# do not create $LONG; we want to trigger the error
+	git credential-cache --socket "$PWD/$LONG/socket" exit
+'
+
 helper_test_timeout cache --timeout=1
 
 test_done

So I don't know if it's worth adding in to your patch. The fix itself is
obviously correct.

-Peff

  parent reply	other threads:[~2025-01-29 20:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-29 16:24 [PATCH 0/2] Plug two memory leaks exposed via Meson Patrick Steinhardt
2025-01-29 16:24 ` [PATCH 1/2] unix-socket: fix memory leak when chdir(3p) fails Patrick Steinhardt
2025-01-29 17:21   ` Junio C Hamano
2025-01-29 20:07     ` Jeff King
2025-01-30  6:02       ` Patrick Steinhardt
2025-01-30 17:35         ` Junio C Hamano
2025-01-29 16:24 ` [PATCH 2/2] scalar: free result of `remote_default_branch()` Patrick Steinhardt
2025-01-29 20:05 ` Jeff King [this message]
2025-01-30  6:04   ` [PATCH 0/2] Plug two memory leaks exposed via Meson Patrick Steinhardt
2025-01-30  6:17 ` [PATCH v2 " Patrick Steinhardt
2025-01-30  6:17   ` [PATCH v2 1/2] unix-socket: fix memory leak when chdir(3p) fails Patrick Steinhardt
2025-01-30  6:17   ` [PATCH v2 2/2] scalar: free result of `remote_default_branch()` Patrick Steinhardt
2025-01-30 19:19   ` [PATCH v2 0/2] Plug two memory leaks exposed via Meson Junio C Hamano

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