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 1E94FEB64DC for ; Fri, 21 Jul 2023 05:18:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 552AE280196; Fri, 21 Jul 2023 01:18:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 503FE280190; Fri, 21 Jul 2023 01:18:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3CA6B280196; Fri, 21 Jul 2023 01:18:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 2DAE9280190 for ; Fri, 21 Jul 2023 01:18:59 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E705D16014D for ; Fri, 21 Jul 2023 05:18:58 +0000 (UTC) X-FDA: 81034464756.27.E011514 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf24.hostedemail.com (Postfix) with ESMTP id 0D3B3180003 for ; Fri, 21 Jul 2023 05:18:56 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=eB4YsL4n; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf24.hostedemail.com: domain of gregkh@linuxfoundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1689916737; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=OyCkBaxm3KJrw96ytVBxzghcNRSZ23BN2/Zj+qsmnvI=; b=BLpMVNZXZ6bXwSTpApDSYKbQEgMvndhNZG5zuz2FdFeUeO0vMxWelxaTs8vP19o/lmOLBg WwYx1wCS9qGDRSixVs/uDBGPYY8Z6BqPKCtlEt1YLshikzDwVgDcjz0/NJMhrNFWdmJ+Md fctHku3ayEkNzQShDT2ckasVLsMz4sM= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=eB4YsL4n; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf24.hostedemail.com: domain of gregkh@linuxfoundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1689916737; a=rsa-sha256; cv=none; b=m2tfIdJq6oA7ostuQ25hJ7jgRsK+lHkLgakOAolo77kfEylk2cx1bwHhgeWnSTPdiAeu5j G9D+51aVhUbCMk3DVqjS37/ImHCmvBZk8/Kf6S12PdN2wDvhi80eAn1wUsNQT8XnSGi2is ydbo0CHDD3snv16RWMAODOuk5LdTtdw= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id F0DA56108F; Fri, 21 Jul 2023 05:18:55 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B047DC433C7; Fri, 21 Jul 2023 05:18:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689916735; bh=TTI/GlElwDYyih0KOVoE5zW1kAkMrgogNBmCmy5UeQk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eB4YsL4nxl0qIm/TpuKDY5S2GXuAh7qGicWKVqPsmqj1DSokXbdb4/nHPW8ZQI4Ug vP1f7ciEphR0wgaHQ+b7zviAYPPivdW7iK2rb12SZWX0YiDJFaZwygnyLFw4aZgtUH 0GCssRGE0VB8x3pHjshGBuCRKO+snluglPtNdOYo= Date: Fri, 21 Jul 2023 07:18:52 +0200 From: Greg KH To: SeongJae Park Cc: ryan.roberts@arm.com, akpm@linux-foundation.org, hch@lst.de, kirill.shutemov@linux.intel.com, lstoakes@gmail.com, rppt@kernel.org, stable@vger.kernel.org, urezki@gmail.com, willy@infradead.org, yuzhao@google.com, ziy@nvidia.com, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5.15.y] mm/damon/ops-common: atomically test and clear young on ptes and pmds Message-ID: <2023072144-item-cosmic-5c73@gregkh> References: <2023071613-reminder-relapse-b922@gregkh> <20230717193008.122040-1-sj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230717193008.122040-1-sj@kernel.org> X-Rspamd-Queue-Id: 0D3B3180003 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: nwexfxxdzp7x3n5ku6ckk9676eza4scn X-HE-Tag: 1689916736-469104 X-HE-Meta: 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 OL4bCwtk 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 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: On Mon, Jul 17, 2023 at 07:30:08PM +0000, SeongJae Park wrote: > From: Ryan Roberts > > commit c11d34fa139e4b0fb4249a30f37b178353533fa1 upstream. > > It is racy to non-atomically read a pte, then clear the young bit, then > write it back as this could discard dirty information. Further, it is bad > practice to directly set a pte entry within a table. Instead clearing > young must go through the arch-provided helper, > ptep_test_and_clear_young() to ensure it is modified atomically and to > give the arch code visibility and allow it to check (and potentially > modify) the operation. > > Link: https://lkml.kernel.org/r/20230602092949.545577-3-ryan.roberts@arm.com > Fixes: 3f49584b262c ("mm/damon: implement primitives for the virtual memory address spaces"). > Signed-off-by: Ryan Roberts > Reviewed-by: Zi Yan > Reviewed-by: SeongJae Park > Reviewed-by: Mike Rapoport (IBM) > Cc: Christoph Hellwig > Cc: Kirill A. Shutemov > Cc: Lorenzo Stoakes > Cc: Matthew Wilcox (Oracle) > Cc: Uladzislau Rezki (Sony) > Cc: Yu Zhao > Cc: > Signed-off-by: Andrew Morton > Signed-off-by: SeongJae Park > --- > This is a manual backport of the commit, which cannot cleanly > cherry-picked on 5.15.y[1], on 5.15.y, specifically 5.15.120. > > [1] https://lore.kernel.org/stable/2023071613-reminder-relapse-b922@gregkh/ Now queued up, thanks. greg k-h