From owner-svn-src-head@freebsd.org Thu May 17 17:38:22 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8D674EDAA5C; Thu, 17 May 2018 17:38:22 +0000 (UTC) (envelope-from cse.cem@gmail.com) Received: from mail-io0-f179.google.com (mail-io0-f179.google.com [209.85.223.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 2121A6BECA; Thu, 17 May 2018 17:38:21 +0000 (UTC) (envelope-from cse.cem@gmail.com) Received: by mail-io0-f179.google.com with SMTP id p124-v6so2992255iod.1; Thu, 17 May 2018 10:38:21 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:reply-to:in-reply-to:references :from:date:message-id:subject:to:cc; bh=mjQpYJnYsxenrlIVkO+QKItVTC1ib+KcGqZosOJPUEc=; b=OjqgQnm3wTednKkF4Z21ylzBMUz4kkXKg9Sv1FJzVTHm0vZRgITlLxyZr/0VXYcOoc WeHY+/bYx8dWUDx15juYQEawawK5EPQi+VeuNJjzu0l8hoGrfL/hdODcyg0Ib1tdfP3c 4v7eSjrTyPrh4OPCXa5lFNNgU7KS16QSFcyNXXhKM/kf6QMyobdd7+lwIxuOprZ/AtTC gzWZAiBBUm3VZY7niM8VacEyPj2hHUUZEkRU/QdddzWRGYJQADJp7OqEeqmUuF9qgr6L svmruDio9/xTguxla3PVy6azFIoqIic6j9HOhMIBsgCH4jbrutI2Y3QRP+2oYOF/CewQ Km6g== X-Gm-Message-State: ALKqPwf+m2D3f1s3Ver8el1eMrSSBmtTP484Se1eRPfHDzJU+yyUj0o+ eKQDH54xnLph+JXlbKa6xylfnHm+ X-Google-Smtp-Source: AB8JxZqzuVmjO8RknlOmwxwnFk0gmTo+MwSoxQEu1egUc+49JX6ce58Xi/WyC4pvjhTMvMA3CfAB4g== X-Received: by 2002:a6b:9bcc:: with SMTP id d195-v6mr6679891ioe.15.1526576854959; Thu, 17 May 2018 10:07:34 -0700 (PDT) Received: from mail-it0-f50.google.com (mail-it0-f50.google.com. [209.85.214.50]) by smtp.gmail.com with ESMTPSA id c90-v6sm3417684itd.13.2018.05.17.10.07.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 17 May 2018 10:07:34 -0700 (PDT) Received: by mail-it0-f50.google.com with SMTP id j186-v6so9737113ita.5; Thu, 17 May 2018 10:07:34 -0700 (PDT) X-Received: by 2002:a24:7d0f:: with SMTP id b15-v6mr3583636itc.135.1526576854535; Thu, 17 May 2018 10:07:34 -0700 (PDT) MIME-Version: 1.0 Reply-To: cem@freebsd.org Received: by 2002:a02:d81:0:0:0:0:0 with HTTP; Thu, 17 May 2018 10:07:34 -0700 (PDT) In-Reply-To: <201805170427.w4H4R8lv058775@repo.freebsd.org> References: <201805170427.w4H4R8lv058775@repo.freebsd.org> From: Conrad Meyer Date: Thu, 17 May 2018 10:07:34 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: svn commit: r333703 - head/sys/vm To: Mark Johnston Cc: src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 May 2018 17:38:22 -0000 On Wed, May 16, 2018 at 9:27 PM, Mark Johnston wrote: > Author: markj > Date: Thu May 17 04:27:08 2018 > New Revision: 333703 > URL: https://svnweb.freebsd.org/changeset/base/333703 > > Log: > Fix a race in vm_page_pagequeue_lockptr(). > > The value of m->queue must be cached after comparing it with PQ_NONE, > since it may be concurrently changing. > > Reported by: glebius What were the symptoms of this issue? The test plan in the linked phabricator revision says: "Gleb reported seeing panics as a result of the use of a bogus index into the pagequeue array, and also reported that this patch fixed the panics." So an attempt to lock pagequeues[PQ_NONE=255].pq_mutex, which is either something later in the vm_domain object, or bogus memory? One of the mtx asserts trips? Thanks, Conrad