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From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Patrick Steinhardt <ps@pks.im>,
	 git@vger.kernel.org,
	 Guillaume Chauvel <guillaume.chauvel@gmail.com>,
	 Philippe Blain <levraiphilippeblain@gmail.com>
Subject: Re: [PATCH 2/2] packfile: fix corruption due to stale delta base cache entries
Date: Wed, 07 Oct 2026 11:00:56 -0700	[thread overview]
Message-ID: <xmqqcxtl8k6f.fsf@gitster.g> (raw)
In-Reply-To: <20261007081844.GA606386@coredump.intra.peff.net> (Jeff King's message of "Wed, 7 Oct 2026 04:18:44 -0400")

Jeff King <peff@peff.net> writes:

> Ah, I get it now. It is a little funny to key the hash on the in-core
> pointer we happen to have, but it does provide a certain uniqueness. I
> suspect that doing this would be mostly correct:
> ...
> and would trigger the use-after-free, but:
>
>   1. It introduces weird semantic questions, like: what if you freed and
>      then reopened a pack of the same name and it didn't have the same
>      contents?
>
>   2. It's more expensive.
>
>   3. Changing the bug from "hard to detect hash equality mismatch" to
>      "undefined behavior" is not really much of an improvement. ;)
>
> So I think just fixing the bug is good, along with accepting that it
> only triggered in certain specific cases and testing that. And your
> patch looks like the obviously correct fix.

Thanks for writing and reviewing, all.  Very much appreciated.

Let me mark the topic for 'next'.

  reply	other threads:[~2026-10-07 18:00 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-02  7:34 [PATCH 0/2] packfile: fix corruption due to stale delta base cache entries Patrick Steinhardt
2026-10-02  7:34 ` [PATCH 1/2] packfile: move around `close_pack()` Patrick Steinhardt
2026-10-02 19:02   ` Mark C. Chu-Carroll
2026-10-02 19:38     ` Patrick Steinhardt
2026-10-02  7:34 ` [PATCH 2/2] packfile: fix corruption due to stale delta base cache entries Patrick Steinhardt
2026-10-02 13:34   ` Guillaume Chauvel
2026-10-02 19:34     ` Patrick Steinhardt
2026-10-02 17:48   ` Philippe Blain
2026-10-02 19:37     ` Patrick Steinhardt
2026-10-02 22:23   ` Jeff King
2026-10-05  5:32     ` Patrick Steinhardt
2026-10-07  8:18       ` Jeff King
2026-10-07 18:00         ` Junio C Hamano [this message]
2026-10-06 10:20 ` [PATCH v2 0/2] " Patrick Steinhardt
2026-10-06 10:20   ` [PATCH v2 1/2] packfile: move around `close_pack()` Patrick Steinhardt
2026-10-06 10:20   ` [PATCH v2 2/2] packfile: fix corruption due to stale delta base cache entries Patrick Steinhardt
2026-10-06 19:57     ` Junio C Hamano
2026-10-07  5:29       ` Patrick Steinhardt

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