From patchwork Fri Dec 4 13:16:31 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: riku.voipio@nokia.com X-Patchwork-Id: 40373 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id A150FB6F09 for ; Sat, 5 Dec 2009 09:18:10 +1100 (EST) Received: from localhost ([127.0.0.1]:58516 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NGgTX-0008Gs-MP for incoming@patchwork.ozlabs.org; Fri, 04 Dec 2009 17:18:07 -0500 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NGY22-0006tt-6t for qemu-devel@nongnu.org; Fri, 04 Dec 2009 08:17:10 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1NGY1w-0006sa-QR for qemu-devel@nongnu.org; Fri, 04 Dec 2009 08:17:08 -0500 Received: from [199.232.76.173] (port=58732 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1NGY1t-0006s6-Te for qemu-devel@nongnu.org; Fri, 04 Dec 2009 08:17:02 -0500 Received: from smtp.nokia.com ([192.100.122.233]:55262 helo=mgw-mx06.nokia.com) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1NGY1t-0008Ny-Kl for qemu-devel@nongnu.org; Fri, 04 Dec 2009 08:17:02 -0500 Received: from esebh106.NOE.Nokia.com (esebh106.ntc.nokia.com [172.21.138.213]) by mgw-mx06.nokia.com (Switch-3.3.3/Switch-3.3.3) with ESMTP id nB4DGkAW012122 for ; Fri, 4 Dec 2009 15:16:57 +0200 Received: from esebh102.NOE.Nokia.com ([172.21.138.183]) by esebh106.NOE.Nokia.com with Microsoft SMTPSVC(6.0.3790.3959); Fri, 4 Dec 2009 15:16:55 +0200 Received: from mgw-da01.ext.nokia.com ([147.243.128.24]) by esebh102.NOE.Nokia.com over TLS secured channel with Microsoft SMTPSVC(6.0.3790.3959); Fri, 4 Dec 2009 15:16:54 +0200 Received: from localhost.localdomain (esdhcp041213.research.nokia.com [172.21.41.213]) by mgw-da01.ext.nokia.com (Switch-3.3.3/Switch-3.3.3) with ESMTP id nB4DGnMu029897; Fri, 4 Dec 2009 15:16:52 +0200 From: riku.voipio@nokia.com To: qemu-devel@nongnu.org Date: Fri, 4 Dec 2009 15:16:31 +0200 Message-Id: <8854a55127930f5eb009ec9a235871917cce0c8d.1259931926.git.riku.voipio@nokia.com> X-Mailer: git-send-email 1.6.3.3 In-Reply-To: References: In-Reply-To: References: X-OriginalArrivalTime: 04 Dec 2009 13:16:55.0343 (UTC) FILETIME=[0D0753F0:01CA74E4] X-Nokia-AV: Clean X-detected-operating-system: by monty-python.gnu.org: GNU/Linux 2.6 (newer, 1) X-Mailman-Approved-At: Fri, 04 Dec 2009 17:12:56 -0500 Cc: Riku Voipio Subject: [Qemu-devel] [PATCH 2/3] linux-user: Fix mmap_lock ordering X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org From: Riku Voipio mmap_lock() can be called while tb_lock() is being held. To avoid deadlock when one thread is holding mmap_lock and another tb_lock, _always_ lock first tb_lock(). Signed-off-by: Riku Voipio --- linux-user/main.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/linux-user/main.c b/linux-user/main.c index 5fbcda2..2015f32 100644 --- a/linux-user/main.c +++ b/linux-user/main.c @@ -99,13 +99,14 @@ static int pending_cpus; /* Make sure everything is in a consistent state for calling fork(). */ void fork_start(void) { - mmap_fork_start(); pthread_mutex_lock(&tb_lock); pthread_mutex_lock(&exclusive_lock); + mmap_fork_start(); } void fork_end(int child) { + mmap_fork_end(child); if (child) { /* Child processes created by fork() only have a single thread. Discard information about the parent threads. */ @@ -122,7 +123,6 @@ void fork_end(int child) pthread_mutex_unlock(&exclusive_lock); pthread_mutex_unlock(&tb_lock); } - mmap_fork_end(child); } /* Wait for pending exclusive operations to complete. The exclusive lock