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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C08E5C433F5 for ; Thu, 26 May 2022 18:31:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236404AbiEZSbz (ORCPT ); Thu, 26 May 2022 14:31:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38358 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233171AbiEZSbq (ORCPT ); Thu, 26 May 2022 14:31:46 -0400 Received: from mail-ed1-x536.google.com (mail-ed1-x536.google.com [IPv6:2a00:1450:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 254052714D for ; Thu, 26 May 2022 11:31:43 -0700 (PDT) Received: by mail-ed1-x536.google.com with SMTP id h11so2795486eda.8 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=PEnh+uxf7YKYsHPnrLMROIh8cM/kJIPTNTR3c90qT/ui6X4PKtJUb49bRbJ8q/TTY1 O1QH1x9NblGdknx6X+kv4jQhRIf75cqMEIS2xU8tvOE7Z6OVlFzz/0ii3THwOTFRGdi+ CxO4TlLK2lofObhLdu0EK9GwQVazmMzZFIbJ+W5NEJvRDJbGrhHg8qMamknhB8yCnEB5 YDXYDBbhURpkixWLcTNGBR1FS83Lwxo4rEnDAyRnDdBjtbkkYjkOqTQKlTVnvKBAOX4d k261xtz8V7DgczPOECr8Fx4NuXZjhUWIGGKLzAkN9tJC43cgBWrDRdJmH8g+DcPrcV19 EY1Q== X-Gm-Message-State: AOAM532zprev/AYBzmKi2ppc94wki+/2mXzE3SU8idI1JV6OhFqbBg3D FoRidq9IKkU9/pRUUI66dN/KgenIFC7D/4ttFMwtcA== 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" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > 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