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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12487C433EF for ; Thu, 26 May 2022 18:31:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 916CA8D0005; Thu, 26 May 2022 14:31:44 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8C1CB8D0002; Thu, 26 May 2022 14:31:44 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 787CA8D0005; Thu, 26 May 2022 14:31:44 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 60F6E8D0002 for ; Thu, 26 May 2022 14:31:44 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 342BE685 for ; Thu, 26 May 2022 18:31:44 +0000 (UTC) X-FDA: 79508737728.08.625570F Received: from mail-ed1-f51.google.com (mail-ed1-f51.google.com [209.85.208.51]) by imf21.hostedemail.com (Postfix) with ESMTP id 452BD1C003C for ; Thu, 26 May 2022 18:31:31 +0000 (UTC) Received: by mail-ed1-f51.google.com with SMTP id fd25so2812073edb.3 for ; Thu, 26 May 2022 11:31:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=OqaDyen+xHLMjM1+kU3vv7vEUmDoXnKLSHCxr0ki/yI=; b=BkgFlzuGNKyb+uNyGnU6TxJ6tLPcnTTz0fIfAd0G6SJqAnBMulcPqqFv87YZb40zBr 45DtchsOB/RWvL1ETS2WM5vNZNWwcoQi6eUXN3Y8ht6azoD9p5U3j+SjLzDTj5jRzMFr mWYp8z+Lw27JzV6nLRO784rXgmDzNNVW1X4rPhGqT9CcDL8N1xECKwkUKmAH6hwNip8o tSoFF1Gw5harFb5i08n4Q7kK2a6o3lPbBYAZ1gbMnFKFovTyzUOrKznNLujUO78M392n snBE7BSEouVeDgQ6JuN5/Yu3lgHzFryGE7lN27p/JX2G+Yeoipo1Iq2B6uT8zo0Dp3kg Y26A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=OqaDyen+xHLMjM1+kU3vv7vEUmDoXnKLSHCxr0ki/yI=; b=d7IsYMa2n0yjDR9hJ+REUiji1219JjvhsKB7HNOuSCh/foIKZGXsjeRqoc+c5IPhA3 D237yaYq/kPAD9X3VaWQNF6qTPNAV6hLNnhJcnl4BlXGGj37K+krIWOLkzL2+XxOWfyt eDOz2ujT8xNkTulG3Ems4PQ5XA2OoRHjVrdPTSz1fuAtDdQQ4ZRgFhWk+LBLiPkJx468 uqH6inbOlJO+4h0SlpN5fkO5YAP2lGG6pkLlBaBk8CtIOd+76FgGUSOS3eJP1IPRHO3F yXWpJpXoo5SMuWbj4gBwqsDYbyZQ/fxLsoSO2Qa5dNoOGfPZk6+ORWnvtfrcGboeCjl0 Q98Q== X-Gm-Message-State: AOAM5339CyWrScGszqLdByibJgnlGM6EbByIVkFnJ+gDrTEwAlf/KDeg jqkocUXKHIHXUxhyxclY0wjfRnQiZEN2gK3qArOGpA== X-Google-Smtp-Source: ABdhPJx0eHADBVzR9F6OjFXojGL3k6dCwZofMe8lUrMYlUp5GceoNL/vvUAdvoESE6uYkZYs+3Ly5be4VSp7LeVAaXM= X-Received: by 2002:aa7:dccd:0:b0:42b:d509:b5b with SMTP id w13-20020aa7dccd000000b0042bd5090b5bmr6266347edu.19.1653589902378; Thu, 26 May 2022 11:31:42 -0700 (PDT) MIME-Version: 1.0 References: <20220526113350.30806-1-linmiaohe@huawei.com> <20220526111546.50102da288cccbe913cadbf4@linux-foundation.org> In-Reply-To: <20220526111546.50102da288cccbe913cadbf4@linux-foundation.org> From: Pasha Tatashin Date: Thu, 26 May 2022 14:31:06 -0400 Message-ID: Subject: Re: [PATCH] mm/page_table_check: fix accessing unmapped ptep To: Andrew Morton Cc: Matthew Wilcox , Miaohe Lin , David Rientjes , linux-mm , LKML Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 452BD1C003C X-Stat-Signature: 6briqzugdf9owneqy9ajmethmyog6kaj X-Rspam-User: Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=BkgFlzuG; spf=pass (imf21.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.208.51 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=none X-HE-Tag: 1653589891-550393 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > > Miaohe, please store the ptep, or maybe drop this patch entirely. > > I think it's best to fix it. I rewrote the changelog as > > : ptep is unmapped too early, so ptep could theoretically be accessed while > : it's unmapped. This might become a problem if/when CONFIG_HIGHPTE becomes > : available on riscv. > : > : Fix it by deferring pte_unmap() until page table checking is done. > > I'll retain the Fixes:. This doesn't imply cc:stable in MM, and anyone > who backports the original patchset will want to know about this fixup. Makes sense. > And I queued a fixup for the thing Matthew noticed. Thank you Andrew. Pasha