From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 617E8C432C0 for ; Wed, 27 Nov 2019 14:23:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 36EB320637 for ; Wed, 27 Nov 2019 14:23:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="NVsRjIUc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727227AbfK0OXu (ORCPT ); Wed, 27 Nov 2019 09:23:50 -0500 Received: from mail-lf1-f66.google.com ([209.85.167.66]:37221 "EHLO mail-lf1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726729AbfK0OXu (ORCPT ); Wed, 27 Nov 2019 09:23:50 -0500 Received: by mail-lf1-f66.google.com with SMTP id b20so17323539lfp.4 for ; Wed, 27 Nov 2019 06:23:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=NQAc09iOSs+OUg5bzPj2H1rBE2GvXaGtHzNxY2vVFm8=; b=NVsRjIUcwILPd1tnDv3S17qPH2Rc8pdEr06OlwognC5L1wYvuuWE2VmFAVum6Qb1sC lmVgIpOLWlVMCndd202EatqCqX9bWwKuQpuknmnYAvNBZuRM0nfXZWN+zzgPxEDxXtNP jo3HcmJ7bYOf3vgkcdZcmnDKCfYRUit71JHPUh0YjkuskgVPvkpJtC7gGesDIl5k/ASd TnVlq3uYhRek3JP6dVNkz96AweylBNW4uXW04xnsmUiSETC69B8fHHkaoIdGKO35hm8Y 2kalCjn+HqYa1IEXmMSEhDzdLjntmK6J3oLzeaoyaS1e+VSazkpj5LuLvCDr9RKRbaqp qWhA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=NQAc09iOSs+OUg5bzPj2H1rBE2GvXaGtHzNxY2vVFm8=; b=qXh6BhVT/tKtT3ru67dV7ezgW+b2aOyZD5A1WjRb22WnXIl9hSEZ+64FEJb4EMYe0p 4fZG1vxya98L1bntcoRcFoEyZ13NRBWYo3yITVpCUWgaJo6NIvLk5GDa9Kmix64eLuPa uXXWxZn8ooZ9QeENodt4bYX1PxK9qBobgN6vz0oGNKhQgdTZIzF5dE+sADewmzCA7eLi CJm8JfuIbVmJ6BZ0aiAgDAsYNmH1swi9cEk12Z+7RCdVLF8RKmY8kM8NNw1tyVvDXNzc A2RvMyWvjqtsm3861U84ZPqISdouKx2YDGvN3t4I3//K/HkCjwLRLxM5HGuu0r2/f+p+ 7iSw== X-Gm-Message-State: APjAAAWmn6tkyQTEnBoBTrvBSYy3loSVQdQOL8Y84/J8+trgWjDr92O7 EyIkaGerOjHvO7llRxvh/6VH2vtk X-Google-Smtp-Source: APXvYqzhLx4HT6/iHXYY/lRbgzvswtQ8BpAwyny4yrxeVKhWIvSHhwsbr3b6fJNLMHfbnSj4C4QlJQ== X-Received: by 2002:ac2:4c82:: with SMTP id d2mr15617326lfl.62.1574864626598; Wed, 27 Nov 2019 06:23:46 -0800 (PST) Received: from seldlx21914.corpusers.net ([37.139.156.40]) by smtp.gmail.com with ESMTPSA id t8sm6975946lfl.51.2019.11.27.06.23.45 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Nov 2019 06:23:46 -0800 (PST) Date: Wed, 27 Nov 2019 15:23:45 +0100 From: Vitaly Wool To: , linux-kernel@vger.kernel.org Cc: Andrew Morton Subject: [PATCH 3/3] z3fold: protect handle reads Message-Id: <20191127152345.8059852f60947686674d726d@gmail.com> In-Reply-To: <20191127152012.17a4b35f9e7f6e50f9aaca9c@gmail.com> References: <20191127152012.17a4b35f9e7f6e50f9aaca9c@gmail.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.30; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org We need to make sure slots are protected on reading a handle. Since handles are modified by free_handle() which only takes slot rwlock, that lock should be used when handles are read. Signed-off-by: Vitaly Wool --- mm/z3fold.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/mm/z3fold.c b/mm/z3fold.c index f2a75418e248..43754d8ebce8 100644 --- a/mm/z3fold.c +++ b/mm/z3fold.c @@ -486,8 +486,12 @@ static unsigned long encode_handle(struct z3fold_header *zhdr, enum buddy bud) /* only for LAST bud, returns zero otherwise */ static unsigned short handle_to_chunks(unsigned long handle) { - unsigned long addr = *(unsigned long *)handle; + struct z3fold_buddy_slots *slots = handle_to_slots(handle); + unsigned long addr; + read_lock(&slots->lock); + addr = *(unsigned long *)handle; + read_unlock(&slots->lock); return (addr & ~PAGE_MASK) >> BUDDY_SHIFT; } @@ -499,10 +503,13 @@ static unsigned short handle_to_chunks(unsigned long handle) static enum buddy handle_to_buddy(unsigned long handle) { struct z3fold_header *zhdr; + struct z3fold_buddy_slots *slots = handle_to_slots(handle); unsigned long addr; + read_lock(&slots->lock); WARN_ON(handle & (1 << PAGE_HEADLESS)); addr = *(unsigned long *)handle; + read_unlock(&slots->lock); zhdr = (struct z3fold_header *)(addr & PAGE_MASK); return (addr - zhdr->first_num) & BUDDY_MASK; } -- 2.17.1