From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-2.0 required=3.0 tests=AWL,BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.6 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id 845121F454 for ; Thu, 13 Apr 2023 13:50:21 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (2048-bit key; unprotected) header.d=github.com header.i=@github.com header.a=rsa-sha256 header.s=google header.b=Vcznfl/H; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231362AbjDMNtl (ORCPT ); Thu, 13 Apr 2023 09:49:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51746 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230383AbjDMNtj (ORCPT ); Thu, 13 Apr 2023 09:49:39 -0400 Received: from mail-yw1-x1136.google.com (mail-yw1-x1136.google.com [IPv6:2607:f8b0:4864:20::1136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66D043584 for ; Thu, 13 Apr 2023 06:49:36 -0700 (PDT) Received: by mail-yw1-x1136.google.com with SMTP id 00721157ae682-54fa9da5e5bso82730047b3.1 for ; Thu, 13 Apr 2023 06:49:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=google; t=1681393775; x=1683985775; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=IACb5aAtTtbyQISNeTgggwiO3frZh3z8ueicizwRlM8=; b=Vcznfl/Hl24p1wuBr9QUnJ0EjJ4e1BOKX/Pc/UyST49MjiSPbPci1DWN5q+eD7hkg4 A5hsqOxBpqK/1HTjxMjIbsJPs5wHvsK/qQhnAyTcE82uQphaPoC+CKRXib/j2hR26LAV hXfbm8OXyQVsDnNfcLSvWxq2baFxxLhsYAztn82t6bL6ws/e9merMHTzLWPEr8bJgbgQ D0Sk8AmwdVMgIcSFY6rckOjxDeST4RenVGTSGWNW7iw3VGpFD5b7oVcH2ukYEvFbjhQr c3zXeSGKNnYhu9sa1pf7/aaWx9rJbqhSmCnowHcwMLEBWm8/7In6BDDyV2jkwDtDb7qv 04CA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1681393775; x=1683985775; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=IACb5aAtTtbyQISNeTgggwiO3frZh3z8ueicizwRlM8=; b=NHNcYiN+7m3npz0i/3dJV2qxKD/bFdQo0hai2RRNp+KrAxyRHl9LbzCtAsns5muALq YBywbVUgLPD717kaNLHOeVjr5wWt5k8gxMHTZ2Y4uZnj6tePFPyb3n5U51r6X+KmgKan +WidhP9wKxdhIncINIJY1zGcfN8x5SIM3wmFE6RXCrqXc6QGXk2ESDDdyQPwhm9N7EAx jU4v+/gUfXpShqDzqbK27yUTRVmlsHoH0Y7N/vEHcqWDaeEnGPRr6M6+wZXNL2G5Euup BE1guH461ft//0V0tKgzWkc8KTXUEp52/MfBY6WGBRTNZcprC4PeopGigK2FtWwpDizK 2KrQ== X-Gm-Message-State: AAQBX9fQkD7cJNG/oKdcT+Gwdzj23ojQ0IPzAT1dYLphFi/n2WjETZcq eLZJfWLcovXxqPp/PlUwes5Q X-Google-Smtp-Source: AKy350adtm7V9ajBR1N8ie5kdCvxZbWZlk+Ae1TmaLyte/XrTtdwIX0jN7QM5YrGDfoPCGaVtRZbAw== X-Received: by 2002:a0d:e205:0:b0:54f:ba16:eee with SMTP id l5-20020a0de205000000b0054fba160eeemr1827891ywe.32.1681393775390; Thu, 13 Apr 2023 06:49:35 -0700 (PDT) Received: from [192.168.1.110] ([99.85.27.166]) by smtp.gmail.com with ESMTPSA id 195-20020a810fcc000000b00545a08184f6sm453413ywp.134.2023.04.13.06.49.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 13 Apr 2023 06:49:35 -0700 (PDT) Message-ID: <1d2e1796-c305-0876-533c-2fe0fd39d722@github.com> Date: Thu, 13 Apr 2023 09:49:34 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH v3 01/10] midx: fix segfault with no packs and invalid preferred pack Content-Language: en-US To: Patrick Steinhardt , git@vger.kernel.org Cc: Taylor Blau , peff@peff.net, dstolee@microsoft.com References: From: Derrick Stolee In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On 4/13/2023 7:16 AM, Patrick Steinhardt wrote: > Fix this bug by resetting the preferred packfile index to `-1` before > searching for the preferred pack. This fixes the segfault as we already > check for whether the index is `> - 1`. If it is not, we simply don't > pick a preferred packfile at all. > if (preferred_pack_name) { > - int found = 0; > + ctx.preferred_pack_idx = -1; > + This patch looks good, but I did need to think about it for a bit, so here are my thoughts (feel free to ignore): I briefly considered recommending that we set this as the default in an initializer macro, something like #define WRITE_MIDX_CONTEXT_INIT { .preferred_pack_idx = -1 } but this struct is internal to the file and only constructed once (at the start of write_midx_internal). Further, outside the context of this patch we have this code: } else if (ctx.nr && (flags & (MIDX_WRITE_REV_INDEX | MIDX_WRITE_BITMAP))) { struct packed_git *oldest = ctx.info[ctx.preferred_pack_idx].p; ctx.preferred_pack_idx = 0; I don't see a way that ctx.preferred_pack_idx can be anything but zero here, but it's also not going to give a segfault because of the 'ctx.nr' condition. Thanks, -Stolee