From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 78D77EB64DD for ; Mon, 14 Aug 2023 10:49:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qVV7W-00072n-IU; Mon, 14 Aug 2023 06:48:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qVV7Q-00071s-Tt for qemu-devel@nongnu.org; Mon, 14 Aug 2023 06:48:17 -0400 Received: from mail-wr1-x42b.google.com ([2a00:1450:4864:20::42b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qVV7O-00088n-GL for qemu-devel@nongnu.org; Mon, 14 Aug 2023 06:48:15 -0400 Received: by mail-wr1-x42b.google.com with SMTP id ffacd0b85a97d-3178dd771ceso3758939f8f.2 for ; Mon, 14 Aug 2023 03:48:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1692010092; x=1692614892; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:from:to:cc:subject:date :message-id:reply-to; bh=LxLZKLEQvAnUN36RxqNEU5N+4uqPL2AVJzYAPj86+RI=; b=M3u9bcbnJoK04BcqSxunO51l34VCc6L2R0h/fE9LT+taN10e5RZsMrrvdWOGjt7pcs Pv4dxZ4Iz4KO8QQ8HPPQGtNPxlzkurdua1dm2HpbrDNWTnbP5hkjTcNeprqa+bV8IJjv qbPDGwnU01bXJk1riwSvFKqOTsz7tj9iG1jkeiVNXJwfH4TDr4z4ixLJvCIRunccOSNO QUdhn7eYglhWF2lUqCqkFuBo5n+nW8O3bqGwSj0iwv49zr6w6/FvWA52hdVHtv0PATco sgs09Q82d8S7AzHKcIOiCVWwtdLLd99UAhw1DdyZy5bs5WeVZj+ZrBQ0DQ2on2owvI95 kMXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692010092; x=1692614892; h=content-transfer-encoding:mime-version:message-id:in-reply-to:date :subject:cc:to:from:user-agent:references:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=LxLZKLEQvAnUN36RxqNEU5N+4uqPL2AVJzYAPj86+RI=; b=do+y69QPYwtqPrYNFhrh1Qv8lbPMRcenSoM0mKQL+eEjPoyt6yf0Y5rvzwzC/ODG5h gq1e/UFrmAzpAUn54x2tu2Ev9oHVkmNDdJWyweSKwN2T94EhSzP4XeA5N0WC5jL1TNWq SqXNYcPq6HXgHjgwvjZgNojFJVjYRN3r/XodzOsFWiXvPcLG71kdNLaoNSw2EvmBrBgw ozkWnd2vpivciq4Mv50B9hWugW3Gplh+5x15AgtZ8MU1uaqHdqh3hvhW82AO1eZi2+vx EIbp2UXJQ52S7uBewvWaESnvksGyPScRCp3u7/LxPTzn4Gb6dGjvoddSSoCIPL1ysA71 NqOQ== X-Gm-Message-State: AOJu0Yx9Fszux6YSXZPn8VD/36j0ZBl0SSWmBxSyaAsUEBFb7N9ri241 gHt5ijOTBYqzQc1P3qEyx/g+xQ== X-Google-Smtp-Source: AGHT+IGQo+tuIJ3DnJhsDNmYaXwCtHh+LZxMnxNWzqYxjXCGD3b0eQqiMAkylRtFvcpJQEMjyIacOA== X-Received: by 2002:a5d:4411:0:b0:317:7081:34c7 with SMTP id z17-20020a5d4411000000b00317708134c7mr6798273wrq.44.1692010092418; Mon, 14 Aug 2023 03:48:12 -0700 (PDT) Received: from zen.linaroharston ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id r7-20020a5d4947000000b003197a4b0f68sm2171393wrs.7.2023.08.14.03.48.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 14 Aug 2023 03:48:12 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 6AFBA1FFBB; Mon, 14 Aug 2023 11:48:11 +0100 (BST) References: <20230731084354.115015-1-akihiko.odaki@daynix.com> <20230731084354.115015-2-akihiko.odaki@daynix.com> User-agent: mu4e 1.11.14; emacs 29.1.50 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Akihiko Odaki Cc: Paolo Bonzini , Thomas Huth , Alexandre Iooss , Mahmoud Mandour , Eduardo Habkost , Marcel Apfelbaum , Philippe =?utf-8?Q?Mathieu-Daud?= =?utf-8?Q?=C3=A9?= , Yanan Wang , Richard Henderson , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , John Snow , Cleber Rosa , Peter Maydell , Michael Rolnik , "Edgar E. Iglesias" , Brian Cain , Song Gao , Xiaojuan Yang , Laurent Vivier , Aurelien Jarno , Jiaxun Yang , Aleksandar Rikalo , Chris Wulff , Marek Vasut , Stafford Horne , Daniel Henrique Barboza , =?utf-8?Q?C=C3=A9dric?= Le Goater , David Gibson , Greg Kurz , Nicholas Piggin , Palmer Dabbelt , Alistair Francis , Bin Meng , Weiwei Li , Liu Zhiwei , Yoshinori Sato , David Hildenbrand , Ilya Leoshkevich , Mark Cave-Ayland , Artyom Tarasenko , Bastian Koppelmann , Max Filippov , qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, qemu-riscv@nongnu.org, qemu-s390x@nongnu.org Subject: Re: [RFC PATCH 01/24] contrib/plugins: Use GRWLock in execlog Date: Mon, 14 Aug 2023 11:48:06 +0100 In-reply-to: <20230731084354.115015-2-akihiko.odaki@daynix.com> Message-ID: <87leedsxw4.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::42b; envelope-from=alex.bennee@linaro.org; helo=mail-wr1-x42b.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Akihiko Odaki writes: > execlog had the following comment: >> As we could have multiple threads trying to do this we need to >> serialise the expansion under a lock. Threads accessing already >> created entries can continue without issue even if the ptr array >> gets reallocated during resize. > > However, when the ptr array gets reallocated, the other threads may have > a stale reference to the old buffer. This results in use-after-free. > > Use GRWLock to properly fix this issue. > > Fixes: 3d7caf145e ("contrib/plugins: add execlog to log instruction execu= tion and memory access") > Signed-off-by: Akihiko Odaki Reviewed-by: Alex Benn=C3=A9e --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro