From patchwork Wed Aug 2 08:45:49 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akihiko Odaki X-Patchwork-Id: 1815877 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org 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=) 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=z9wjAVBD; dkim-atps=neutral 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 4RG5Hq1L9Hz1yZl for ; Wed, 2 Aug 2023 18:49:11 +1000 (AEST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qR7VM-0005oh-9O; Wed, 02 Aug 2023 04:46:52 -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 1qR7VL-0005oB-7a for qemu-devel@nongnu.org; Wed, 02 Aug 2023 04:46:51 -0400 Received: from mail-pf1-x42b.google.com ([2607:f8b0:4864:20::42b]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1qR7VI-0005P5-Gd for qemu-devel@nongnu.org; Wed, 02 Aug 2023 04:46:50 -0400 Received: by mail-pf1-x42b.google.com with SMTP id d2e1a72fcca58-687087d8ddaso5276336b3a.1 for ; Wed, 02 Aug 2023 01:46:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20221208.gappssmtp.com; s=20221208; t=1690966007; x=1691570807; 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=Rv8ecp5MNNYaYzflXkXYlG6pC6Fau5qFV5g6norDKWY=; b=z9wjAVBDpHMbkG6eQ1r3e9ny+mLCXFsCxQQo9SYfOOWYUY/RQPMbUkymHZVAcfvvUD 3OofNVeHGqhCahnR+/UW17yxhH8ot8q5p/iXgKmsmiPiopZQMEmehFUtMHFDUpXUMfVk mXofmBj+JmzrPOTqZG7I6XcZup+9uM4oJXNVeEmv30/qd/keO32a3USFQhIgSLQ2PZ7u ELBSV6eteUtIFtJwqeXRW0rEr6R0QCQZsTsBYZ7fYa+dC1y5OXxZ9DtIg3tGbuy/IG6J j6FW/Ud5yeigEy+TXBLOTHiZEH8VDLmJMNPu7hi/EtSV7v2v92EAuOQt7Ymv2pxyXYKY Q0Fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690966007; x=1691570807; 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=Rv8ecp5MNNYaYzflXkXYlG6pC6Fau5qFV5g6norDKWY=; b=fErJw3PFTMiU2CrwuFsIhaUMS92VH25adV10Bvav0MA27nWhEOb8MJpI9kxWzey3y/ POB3bLUfxywfLgzzt85QwGXwaVBjEAuTguDKdRnuPNOIoDE+9d25Wl4VsyFKf3/wW1Fg UicW/FMJTMAHQ6cIr0P5RbI4sadkL/DxQY1ROeboMWI5qjg9NIpkLUZff21SFVklE8PA S3Ned7p5OaoEI61eDmK2nvTXFYVBlLmOSEAsRU+yIluMHbSDGsV1c7OjyExZo2bFMlO8 dsumlGiMFCHvWuAKLsV8iscCZK2G3UOAqyKdOt16BDRUQFU0xabgx1RUMWlf47PvTa/U SItQ== X-Gm-Message-State: ABy/qLakR0kLXyxm3HGYzpyIeNUpr/A8dToCIFOAY5mqZxFyOrId2j8v 7JDyYUu9yFOyTUDQPY0H4cYXog== X-Google-Smtp-Source: APBJJlFbT3djjGa3AhGETEN9Ly5DOGsyt62WPoYE4syhoesTaxfMJ77VjnntAWiN77OHXldGylrOGA== X-Received: by 2002:a05:6a20:7355:b0:116:d935:f742 with SMTP id v21-20020a056a20735500b00116d935f742mr16115776pzc.20.1690966007186; Wed, 02 Aug 2023 01:46:47 -0700 (PDT) Received: from alarm.flets-east.jp ([2400:4050:a840:1e00:78d2:b862:10a7:d486]) by smtp.gmail.com with ESMTPSA id j22-20020aa79296000000b00659b8313d08sm10592860pfa.78.2023.08.02.01.46.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Aug 2023 01:46:46 -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 v2 01/24] contrib/plugins: Use GRWLock in execlog Date: Wed, 2 Aug 2023 17:45:49 +0900 Message-ID: <20230802084614.23619-2-akihiko.odaki@daynix.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230802084614.23619-1-akihiko.odaki@daynix.com> References: <20230802084614.23619-1-akihiko.odaki@daynix.com> MIME-Version: 1.0 Received-SPF: none client-ip=2607:f8b0:4864:20::42b; envelope-from=akihiko.odaki@daynix.com; helo=mail-pf1-x42b.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, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable 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 --- 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) {