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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8D3F1CCD1A5 for ; Fri, 24 Oct 2025 07:44:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DA08D8E0049; Fri, 24 Oct 2025 03:44:17 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D284C8E0042; Fri, 24 Oct 2025 03:44:17 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BF1C68E0049; Fri, 24 Oct 2025 03:44:17 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id A8B4D8E0042 for ; Fri, 24 Oct 2025 03:44:17 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 61108C0DDA for ; Fri, 24 Oct 2025 07:44:17 +0000 (UTC) X-FDA: 84032219754.09.B71B395 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf06.hostedemail.com (Postfix) with ESMTP id 36364180006 for ; Fri, 24 Oct 2025 07:44:13 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=none; spf=pass (imf06.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761291855; a=rsa-sha256; cv=none; b=mjSOUey6yeON/Q2F+ya+ChdMgO11mvHKI598uyRtZSj1Nm9O01ylEE14GT8pa/0gZMYUBb eu+PXr1+MEbgXVpLjDFsipZaUHAuix8stgDLinUHH+P2x2+iSZhdT7scU2nV3KXMVTJfeA vzKweB9GvqRuqrg+UP2B0jwKlE7adbQ= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=none; spf=pass (imf06.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761291855; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rulU+unUCqrjU3BR5sVJyXLG2vkLgdcaRwHM1Jnddl8=; b=b2llEF/Xy8S/GUBMjwi7eE/5QPTjFY8fhzyi2spGuoW7/JahNMHhO4eG3VxKW9b+Ljc9Ot Et76rQysLpd2c688rSS4wkgwdmEvHrvz6hmguUP6e1v1L48fwz04KaMhHhBXu+jha1vpjT 2jRBLXrAzfvr82NOWCSC273utFVNvy8= Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4ctFCf6wB6zTh71; Fri, 24 Oct 2025 15:39:26 +0800 (CST) Received: from dggemv706-chm.china.huawei.com (unknown [10.3.19.33]) by mail.maildlp.com (Postfix) with ESMTPS id 02B23180B62; Fri, 24 Oct 2025 15:44:10 +0800 (CST) Received: from kwepemq500010.china.huawei.com (7.202.194.235) by dggemv706-chm.china.huawei.com (10.3.19.33) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 24 Oct 2025 15:44:09 +0800 Received: from [10.173.125.37] (10.173.125.37) by kwepemq500010.china.huawei.com (7.202.194.235) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 24 Oct 2025 15:44:08 +0800 Subject: Re: [PATCH v4] mm/huge_memory: preserve PG_has_hwpoisoned if a folio is split to >0 order To: Zi Yan CC: , , , , Lorenzo Stoakes , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , "Matthew Wilcox (Oracle)" , Wei Yang , "Yang Shi" , , , , , , References: <20251023030521.473097-1-ziy@nvidia.com> From: Miaohe Lin Message-ID: <479c9b79-a8a3-6e14-9264-cda3e9851b43@huawei.com> Date: Fri, 24 Oct 2025 15:44:07 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20251023030521.473097-1-ziy@nvidia.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.125.37] X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To kwepemq500010.china.huawei.com (7.202.194.235) X-Stat-Signature: d81x9s1p5qnm15cbfunpmx5cgrogmm59 X-Rspamd-Queue-Id: 36364180006 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1761291853-383210 X-HE-Meta: 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 bZG+eTJu mjl+SwIPi9RMp/CaQ74Sm59T1SG+X/YI25+/8vsc/u1rLbdp6l3H1r+4rdSQgiOsk1mpBohCcURO+F7YLRNQtXa5EhSxkNybkkYoitdTqOSHqQvugrOGxAQJJ7NkcmsYKh2yqgycPw5VrOoEN+GXrwiGZPVNPd7Jng9JQs+dbGCNoZc/jxQahHqr2mjXaQ3r+BcuMu+S9DoogipZx69Tqte6bNuxCFLPfdDyInQvkcRXYRf1n5Aj5NCQ57FJawLA0tLeSbD4SSGm8DfafY4zH4qkqwVReqZsbYLe/YwmJ3R9U0/rZ9VrfV99FkPp2xLrWSbECboE+ba+zaEhwmg4tPxjPTKHMz3ziL5xX 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: List-Subscribe: List-Unsubscribe: On 2025/10/23 11:05, Zi Yan wrote: > folio split clears PG_has_hwpoisoned, but the flag should be preserved in > after-split folios containing pages with PG_hwpoisoned flag if the folio is > split to >0 order folios. Scan all pages in a to-be-split folio to > determine which after-split folios need the flag. > > An alternatives is to change PG_has_hwpoisoned to PG_maybe_hwpoisoned to > avoid the scan and set it on all after-split folios, but resulting false > positive has undesirable negative impact. To remove false positive, caller > of folio_test_has_hwpoisoned() and folio_contain_hwpoisoned_page() needs to > do the scan. That might be causing a hassle for current and future callers > and more costly than doing the scan in the split code. More details are > discussed in [1]. > > This issue can be exposed via: > 1. splitting a has_hwpoisoned folio to >0 order from debugfs interface; > 2. truncating part of a has_hwpoisoned folio in > truncate_inode_partial_folio(). > > And later accesses to a hwpoisoned page could be possible due to the > missing has_hwpoisoned folio flag. This will lead to MCE errors. > > Link: https://lore.kernel.org/all/CAHbLzkoOZm0PXxE9qwtF4gKR=cpRXrSrJ9V9Pm2DJexs985q4g@mail.gmail.com/ [1] > Fixes: c010d47f107f ("mm: thp: split huge page to any lower order pages") > Cc: stable@vger.kernel.org > Signed-off-by: Zi Yan Thanks for your patch. LGTM. Reviewed-by: Miaohe Lin Thanks. .