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From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: Taylor Blau <me@ttaylorr.com>,
	 git@vger.kernel.org,  Kyle Lippincott <spectral@google.com>,
	 Patrick Steinhardt <ps@pks.im>
Subject: Re: [PATCH v2 2/3] pack-bitmap.c: avoid uninitialized `pack_int_id` during reuse
Date: Tue, 11 Jun 2024 10:03:10 -0700	[thread overview]
Message-ID: <xmqqy17bwgxd.fsf@gitster.g> (raw)
In-Reply-To: <20240611091102.GL3248245@coredump.intra.peff.net> (Jeff King's message of "Tue, 11 Jun 2024 05:11:02 -0400")

Jeff King <peff@peff.net> writes:

> On Mon, Jun 10, 2024 at 04:10:53PM -0400, Taylor Blau wrote:
>
>> Avoid the uninitialized read by ensuring that the pack_int_id field is
>> set in the single-pack reuse case by setting it to either the MIDX
>> preferred pack's pack_int_id, or '0', in the case of single-pack
>> bitmaps.  In the latter case, we never read the pack_int_id field, so
>> the choice of '0' is arbitrary.
>
> Could we set it to some sentinel value for the single-pack case? If we
> set it to "-1", then the BUG() added in patch 3 would trigger if we did
> accidentally try to feed it to the midx code. Assuming you do not have
> 2^32-1 packs, of course. ;)

Yeah, I had exactly the same reaction.

  reply	other threads:[~2024-06-11 17:03 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-06-09 15:27 [PATCH] pack-bitmap.c: avoid uninitialized `pack_int_id` during reuse Taylor Blau
2024-06-10  5:55 ` Patrick Steinhardt
2024-06-10 14:57   ` Taylor Blau
2024-06-11  8:12     ` Patrick Steinhardt
2024-06-10 20:10 ` [PATCH v2 0/3] midx: various brown paper bag fixes Taylor Blau
2024-06-10 20:10   ` [PATCH v2 1/3] midx-write.c: do not read existing MIDX with `packs_to_include` Taylor Blau
2024-06-10 20:10   ` [PATCH v2 2/3] pack-bitmap.c: avoid uninitialized `pack_int_id` during reuse Taylor Blau
2024-06-11  9:11     ` Jeff King
2024-06-11 17:03       ` Junio C Hamano [this message]
2024-06-10 20:10   ` [PATCH v2 3/3] pack-revindex.c: guard against out-of-bounds pack lookups Taylor Blau
2024-06-11 17:28 ` [PATCH v2 0/3] midx: various brown paper bag fixes Taylor Blau
2024-06-11 17:28   ` [PATCH v2 1/3] midx-write.c: do not read existing MIDX with `packs_to_include` Taylor Blau
2024-06-11 17:28   ` [PATCH v2 2/3] pack-bitmap.c: avoid uninitialized `pack_int_id` during reuse Taylor Blau
2024-06-11 17:28   ` [PATCH v2 3/3] pack-revindex.c: guard against out-of-bounds pack lookups Taylor Blau
2024-06-11 17:31   ` [PATCH v2 0/3] midx: various brown paper bag fixes Taylor Blau

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