From patchwork Wed Feb 7 12:05:23 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 10205061 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5CD7A60247 for ; Wed, 7 Feb 2018 12:18:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 42C5F28B79 for ; Wed, 7 Feb 2018 12:18:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3622128F30; Wed, 7 Feb 2018 12:18:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id CB16528B79 for ; Wed, 7 Feb 2018 12:18:57 +0000 (UTC) Received: from localhost ([::1]:57089 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejOgj-0005Ig-1X for patchwork-qemu-devel@patchwork.kernel.org; Wed, 07 Feb 2018 07:18:57 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50485) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejOTe-00019J-Ni for qemu-devel@nongnu.org; Wed, 07 Feb 2018 07:05:36 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ejOTa-0004Tf-2x for qemu-devel@nongnu.org; Wed, 07 Feb 2018 07:05:26 -0500 Received: from mail.ispras.ru ([83.149.199.45]:47640) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ejOTZ-0004TM-Qu for qemu-devel@nongnu.org; Wed, 07 Feb 2018 07:05:22 -0500 Received: from [127.0.1.1] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id D51A154008B; Wed, 7 Feb 2018 15:05:20 +0300 (MSK) From: Pavel Dovgalyuk To: qemu-devel@nongnu.org Date: Wed, 07 Feb 2018 15:05:23 +0300 Message-ID: <20180207120523.5389.91342.stgit@pasha-VirtualBox> In-Reply-To: <20180207120353.5389.54531.stgit@pasha-VirtualBox> References: <20180207120353.5389.54531.stgit@pasha-VirtualBox> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 83.149.199.45 Subject: [Qemu-devel] [RFC PATCH v6 16/20] replay: avoid recursive call of checkpoints X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, peter.maydell@linaro.org, war2jordan@live.com, pavel.dovgaluk@ispras.ru, quintela@redhat.com, ciro.santilli@gmail.com, jasowang@redhat.com, mst@redhat.com, zuban32s@gmail.com, maria.klimushenkova@ispras.ru, dovgaluk@ispras.ru, kraxel@redhat.com, boost.lists@gmail.com, thomas.dullien@googlemail.com, pbonzini@redhat.com, alex.bennee@linaro.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP This patch adds a flag which denies recursive call of replay_checkpoint function. Checkpoints may be accompanied by the hardware events. When event is processed, virtual device may invoke timer modification functions that also invoke the checkpoint function. This leads to infinite loop. Signed-off-by: Pavel Dovgalyuk --- replay/replay.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/replay/replay.c b/replay/replay.c index 585c5de..c676dd4 100644 --- a/replay/replay.c +++ b/replay/replay.c @@ -176,13 +176,24 @@ void replay_shutdown_request(ShutdownCause cause) bool replay_checkpoint(ReplayCheckpoint checkpoint) { bool res = false; + static bool in_checkpoint; assert(EVENT_CHECKPOINT + checkpoint <= EVENT_CHECKPOINT_LAST); - replay_save_instructions(); if (!replay_file) { return true; } + if (in_checkpoint) { + /* If we are already in checkpoint, then there is no need + for additional synchronization. + Recursion occurs when HW event modifies timers. + Timer modification may invoke the checkpoint and + proceed to recursion. */ + return true; + } + in_checkpoint = true; + + replay_save_instructions(); if (replay_mode == REPLAY_MODE_PLAY) { g_assert(replay_mutex_locked()); @@ -204,6 +215,7 @@ bool replay_checkpoint(ReplayCheckpoint checkpoint) res = true; } out: + in_checkpoint = false; return res; }