Re: [PATCH 2/2] packfile: fix corruption due to stale delta base cache entries

From: Jeff King <peff@peff.net>
Date: Oct 2, 2026, 22:23 UTC
Message-ID: <20261002222335.GC833115@coredump.intra.peff.net>
In-Reply-To: <20261002-pks-packfile-stale-delta-base-cache-v1-2-7592a3e31ae0@pks.im>

On Fri, Oct 02, 2026 at 09:34:07AM +0200, Patrick Steinhardt wrote:

Show 5 quoted lines

> Note that the added test reliably reproduces the above bug on my machine
> that uses NixOS at c59305bab206 (cosmic-applets: add missing runtime
> dependency (#566040), 2026-10-01) with glibc 2.44-25. But as we rely on
> specific allocation behaviour of glibc it is very likely that the test
> will not work on other platforms.

At its core this is a user-after-free bug, isn't it? If so, I think it would be fine to say that ASan will reliably find it (and we don't even really need to demonstrate the complex case where the packed_git has the same address; all bets are off once we access the freed pointer).

-Peff