From patchwork Wed Aug 16 14:51:22 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Akihiko Odaki X-Patchwork-Id: 1821881 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=daynix-com.20221208.gappssmtp.com header.i=@daynix-com.20221208.gappssmtp.com header.a=rsa-sha256 header.s=20221208 header.b=IS98RPSo; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=patchwork.ozlabs.org) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4RQrjn6jxWz1xrk for ; Thu, 17 Aug 2023 00:53:33 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qWHst-0005uW-Pj; Wed, 16 Aug 2023 10:52:31 -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 1qWHss-0005uG-GW for qemu-devel@nongnu.org; Wed, 16 Aug 2023 10:52:30 -0400 Received: from mail-pf1-x435.google.com ([2607:f8b0:4864:20::435]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qWHsp-0001D1-J1 for qemu-devel@nongnu.org; Wed, 16 Aug 2023 10:52:29 -0400 Received: by mail-pf1-x435.google.com with SMTP id d2e1a72fcca58-687ca37628eso6275639b3a.1 for ; Wed, 16 Aug 2023 07:52:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20221208.gappssmtp.com; s=20221208; t=1692197546; x=1692802346; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=nZll0H6CXaAKys7cBNNrlAZQAX9ewDlJMrzDsStORGc=; b=IS98RPSoM3bHM532wB3kGFtMQpyITAnx71ZNLFCE00bUEp/cSqOVhZ1K0iA5kpihq6 BRLl2OXfqX34J2J2L2cfhhPuHdiPtzE0pMl77seizCPTDrduCZc5IGAliHm4cIAN758F sFUPNr4oDH5YHSqKjOH4VlyvNm8MAorVsGECwc3Q7HLkGmeWJWX2mV4IcqbNmKDfGJT9 WoO7X0hH2DLxMNn8lj3jzOz3Fn1ZijU8o0LXT7V7w8TwQ2fOJ2S1Ij/ZY07bdTyREdMb KF/9+vHP9w/LU8V7D8rUYw8p9YphgfDHAiJwSE68BRzJ+TJzDWoCrgFT+FPO15FtI9af 3MuA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1692197546; x=1692802346; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=nZll0H6CXaAKys7cBNNrlAZQAX9ewDlJMrzDsStORGc=; b=PlU3v0eyS162cSnuf0B7J9GxTLz9gOx7d6vP3dGwZcfQYFpQiF7bRSGlGeDMGTQFtD hDBC/3LBEvAjVt4gmff91dYau6+3gIN1bywCZHJaStwMAbZUS6cz3sIUlgMieO7A/lB5 fJ1nSDlI/Y4QiwkwDgHaCV0K3YBbUGNelplW1lDU9iUzRU7CP7D67xMaAjgIq1C1Kkan k57CEK/eZT5iQSfhL1qFpiM0IMgbVbPWc3A429oK1OGLuy33IEMeiPxlT7WwImjI4mqz J3FLUaOjPtOxBXwEkn7p9G/N76KYQMSNJ5/VXbE9vqMV6iIUtWo4KX/jr2gfTo90JLFT 06MQ== X-Gm-Message-State: AOJu0Yz3EaAkKT2A2pNwcE73q4ARkI8mIVPePzSzw6MYJQk5DRIFCM22 X+RsIn2Q9ZfzMauh7iqRVvAbmw== X-Google-Smtp-Source: AGHT+IGvqTVlRSSkvBFQxZQ6Oytspddpo1IsISOp9PrJWZtteCsFnXnUM/ejoMkcxYQmUWq95f9M6g== X-Received: by 2002:a05:6a20:5485:b0:133:be9d:a9e6 with SMTP id i5-20020a056a20548500b00133be9da9e6mr3463895pzk.17.1692197546383; Wed, 16 Aug 2023 07:52:26 -0700 (PDT) Received: from alarm.flets-east.jp ([2400:4050:a840:1e00:78d2:b862:10a7:d486]) by smtp.gmail.com with ESMTPSA id fk26-20020a056a003a9a00b0068892c40253sm1156568pfb.216.2023.08.16.07.52.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Aug 2023 07:52:26 -0700 (PDT) From: Akihiko Odaki To: Cc: Paolo Bonzini , =?utf-8?q?Alex_Benn=C3=A9e?= , Thomas Huth , Alexandre Iooss , Mahmoud Mandour , Eduardo Habkost , Marcel Apfelbaum , =?utf-8?q?Philippe_Mathieu-D?= =?utf-8?q?aud=C3=A9?= , Yanan Wang , Richard Henderson , =?utf-8?q?Marc-Andr=C3=A9?= =?utf-8?q?_Lureau?= , =?utf-8?q?Daniel_P_=2E_B?= =?utf-8?q?errang=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_G?= =?utf-8?q?oater?= , 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, Anton Kochkov , Akihiko Odaki Subject: [PATCH v4 01/25] contrib/plugins: Use GRWLock in execlog Date: Wed, 16 Aug 2023 23:51:22 +0900 Message-ID: <20230816145155.21049-2-akihiko.odaki@daynix.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230816145155.21049-1-akihiko.odaki@daynix.com> References: <20230816145155.21049-1-akihiko.odaki@daynix.com> MIME-Version: 1.0 Received-SPF: none client-ip=2607:f8b0:4864:20::435; envelope-from=akihiko.odaki@daynix.com; helo=mail-pf1-x435.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=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+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org 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 execution and memory access") Signed-off-by: Akihiko Odaki Reviewed-by: Alex Bennée --- contrib/plugins/execlog.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/contrib/plugins/execlog.c b/contrib/plugins/execlog.c index 7129d526f8..ce67acf145 100644 --- a/contrib/plugins/execlog.c +++ b/contrib/plugins/execlog.c @@ -19,7 +19,7 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION; /* Store last executed instruction on each vCPU as a GString */ static GPtrArray *last_exec; -static GMutex expand_array_lock; +static GRWLock expand_array_lock; static GPtrArray *imatches; static GArray *amatches; @@ -28,18 +28,16 @@ static GArray *amatches; * Expand last_exec array. * * 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. + * serialise the expansion under a lock. */ static void expand_last_exec(int cpu_index) { - g_mutex_lock(&expand_array_lock); + g_rw_lock_writer_unlock(&expand_array_lock); while (cpu_index >= last_exec->len) { GString *s = g_string_new(NULL); g_ptr_array_add(last_exec, s); } - g_mutex_unlock(&expand_array_lock); + g_rw_lock_writer_unlock(&expand_array_lock); } /** @@ -51,8 +49,10 @@ static void vcpu_mem(unsigned int cpu_index, qemu_plugin_meminfo_t info, GString *s; /* Find vCPU in array */ + g_rw_lock_reader_lock(&expand_array_lock); g_assert(cpu_index < last_exec->len); s = g_ptr_array_index(last_exec, cpu_index); + g_rw_lock_reader_unlock(&expand_array_lock); /* Indicate type of memory access */ if (qemu_plugin_mem_is_store(info)) { @@ -80,10 +80,14 @@ static void vcpu_insn_exec(unsigned int cpu_index, void *udata) GString *s; /* Find or create vCPU in array */ + g_rw_lock_reader_lock(&expand_array_lock); if (cpu_index >= last_exec->len) { + g_rw_lock_reader_unlock(&expand_array_lock); expand_last_exec(cpu_index); + g_rw_lock_reader_lock(&expand_array_lock); } s = g_ptr_array_index(last_exec, cpu_index); + g_rw_lock_reader_unlock(&expand_array_lock); /* Print previous instruction in cache */ if (s->len) {