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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 A7F03ECDE47 for ; Thu, 25 Oct 2018 00:13:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6A82A20831 for ; Thu, 25 Oct 2018 00:13:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Z6XM8dy+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6A82A20831 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726909AbeJYInl (ORCPT ); Thu, 25 Oct 2018 04:43:41 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:58872 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725829AbeJYInl (ORCPT ); Thu, 25 Oct 2018 04:43:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=6Dz0CJy/5m7+uS7QA3MDg01ayJogASJH3CHbkaAtNKw=; b=Z6XM8dy+7o59O0wgwPXKr3rDT DRZveygxmqZfJVMU1fB2fXcFRnXnnwNw6XQ+16NUBI45rqW2WAJ7uFVNLbBywKJDN7f34fFWV111x aIWADb8CNuBUQzKdoQUOIGaFkWu8uI/LNy5qthqVrs2+Qz+xRShczF/QvuiL+QLrzvgqleLXWyWI8 TXt9vxzH6nX1Q9/uA6AMyrVln5fGCdb+1UlzGhKlXnabWG4N4g/GkPIMQMLvkIXVIdG6k0QcBDxzd qQS+F4QOOfr3Urnswjx0BCx+6pip5ZLbmRnVdf9l2bnd2HmqalysQlKud1+0yP78ALXQBLRAzdSaM xFGbJDnFw==; Received: from [167.98.65.38] (helo=worktop) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gFTH2-0001hf-Qq; Thu, 25 Oct 2018 00:13:17 +0000 Received: by worktop (Postfix, from userid 1000) id CC0816E0647; Thu, 25 Oct 2018 02:13:12 +0200 (CEST) Date: Thu, 25 Oct 2018 02:13:12 +0200 From: Peter Zijlstra To: Igor Stoppa Cc: Mimi Zohar , Kees Cook , Matthew Wilcox , Dave Chinner , James Morris , Michal Hocko , kernel-hardening@lists.openwall.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, igor.stoppa@huawei.com, Dave Hansen , Jonathan Corbet , Laura Abbott , Will Deacon , Boqun Feng , Arnd Bergmann , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 16/17] prmem: pratomic-long Message-ID: <20181025001312.GA3159@worktop.c.hoisthospitality.com> References: <20181023213504.28905-1-igor.stoppa@huawei.com> <20181023213504.28905-17-igor.stoppa@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181023213504.28905-17-igor.stoppa@huawei.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 24, 2018 at 12:35:03AM +0300, Igor Stoppa wrote: > +static __always_inline > +bool __pratomic_long_op(bool inc, struct pratomic_long_t *l) > +{ > + struct page *page; > + uintptr_t base; > + uintptr_t offset; > + unsigned long flags; > + size_t size = sizeof(*l); > + bool is_virt = __is_wr_after_init(l, size); > + > + if (WARN(!(is_virt || likely(__is_wr_pool(l, size))), > + WR_ERR_RANGE_MSG)) > + return false; > + local_irq_save(flags); > + if (is_virt) > + page = virt_to_page(l); > + else > + vmalloc_to_page(l); > + offset = (~PAGE_MASK) & (uintptr_t)l; > + base = (uintptr_t)vmap(&page, 1, VM_MAP, PAGE_KERNEL); > + if (WARN(!base, WR_ERR_PAGE_MSG)) { > + local_irq_restore(flags); > + return false; > + } > + if (inc) > + atomic_long_inc((atomic_long_t *)(base + offset)); > + else > + atomic_long_dec((atomic_long_t *)(base + offset)); > + vunmap((void *)base); > + local_irq_restore(flags); > + return true; > + > +} That's just hideously nasty.. and horribly broken. We're not going to duplicate all these kernel interfaces wrapped in gunk like that. Also, you _cannot_ call vunmap() with IRQs disabled. Clearly you've never tested this with debug bits enabled.