From patchwork Fri Aug 12 08:49:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Wang, Haiyue" X-Patchwork-Id: 12942046 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 C8ACAC282E7 for ; Fri, 12 Aug 2022 08:49:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 65C426B0073; Fri, 12 Aug 2022 04:49:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 60B7E8E0002; Fri, 12 Aug 2022 04:49:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4ABEB6B0078; Fri, 12 Aug 2022 04:49:14 -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 3E49F6B0073 for ; Fri, 12 Aug 2022 04:49:14 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 106CBA08D9 for ; Fri, 12 Aug 2022 08:49:14 +0000 (UTC) X-FDA: 79790316228.11.15B776C Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by imf05.hostedemail.com (Postfix) with ESMTP id D4865100186 for ; Fri, 12 Aug 2022 08:49:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1660294151; x=1691830151; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=+nxW0bEQ9sv51ybHeEN8SKdGEjqYmcdcOKMXIfq1QOk=; b=CjQt8SdaO5yGk1Fm9fLLbOmjvFNT9+RqOkiRbjuHOz9eCeiTBFQkf2OJ aEEvBCghSXQdnEuUJ8mrresC8d/sWBhMK6X8oXG6RqRmaMlDdbv7sc39n qGIV847SyuXmKrsI/8DOQruQ7uzJh6LXzo1aopuF9C8+V07bAJl7Ru1t+ 6vtzF3vvGNbrhMBWLGsVT7yqj6/1ngX4yK4ApH02UP/Vh0MSImnOT+u0o 9fCUR2DLNIDAnk5nAj2PrhtSaEbfLbb9axxKn+OHgzjN/PUM8oe1E7Qq6 F06n1/kk8YPugndslR9SKxWTpmaaBMqG60et9BJcxc5oAxngfGE2G6MFQ A==; X-IronPort-AV: E=McAfee;i="6400,9594,10436"; a="289125507" X-IronPort-AV: E=Sophos;i="5.93,231,1654585200"; d="scan'208";a="289125507" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Aug 2022 01:49:09 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.93,231,1654585200"; d="scan'208";a="748128925" Received: from unknown (HELO dsg-bmc-sherry-3.sh.intel.com) ([10.239.138.101]) by fmsmga001.fm.intel.com with ESMTP; 12 Aug 2022 01:49:07 -0700 From: Haiyue Wang To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, david@redhat.com, linmiaohe@huawei.com, ying.huang@intel.com, songmuchun@bytedance.com, naoya.horiguchi@linux.dev, Haiyue Wang Subject: [PATCH v1] mm: migration: fix the FOLL_GET failure on following huge page Date: Fri, 12 Aug 2022 16:49:21 +0800 Message-Id: <20220812084921.409142-1-haiyue.wang@intel.com> X-Mailer: git-send-email 2.37.1 MIME-Version: 1.0 ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=CjQt8Sda; spf=pass (imf05.hostedemail.com: domain of haiyue.wang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=haiyue.wang@intel.com; dmarc=pass (policy=none) header.from=intel.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660294153; a=rsa-sha256; cv=none; b=XRrRdTkKKx+tBpdeRbg+8WgpIXxXP8wG8EmpV79nyJ8eidEWW0+dtRkebFLo6fD4j+BizD +4XGPK0U53By5Mx/Eq0CrJ5MgscZVFnzJGfVUWfEBAJVy26uto6c9vCw4sJLvZTy2RQROw giZd1wUGIlWOJXvC0PFUL41qMSfyxwY= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1660294153; 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-transfer-encoding:content-transfer-encoding: in-reply-to:references:dkim-signature; bh=socs3qV8DZTkpDk6iWXkznHEhmWMDF/db+KLl9HlPO0=; b=g8upWtshRG16dUd6sO9FpuBhL4GFijaeL+RN0+LO28Xj6wk0yZfIeJI8wX2LPXYaNgcKTJ 4ylhrsWYQQ27kDfPxhCJqYvZJMCZ+NLF4zthR6AJfBEYUyOb2hWuTXdnJQ57Xb5fVxfewI eR0esRjTCRrRfvceF3prAzNMSmxhMC4= Authentication-Results: imf05.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=CjQt8Sda; spf=pass (imf05.hostedemail.com: domain of haiyue.wang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=haiyue.wang@intel.com; dmarc=pass (policy=none) header.from=intel.com X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D4865100186 X-Stat-Signature: faoor1r9xmtzaaeem64hkn11ts1p38dc X-Rspam-User: X-HE-Tag: 1660294151-68713 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: Not all huge page APIs support FOLL_GET option, so the __NR_move_pages will fail to get the page node information for huge page. This is an temporary solution to mitigate the racing fix. After supporting follow huge page by FOLL_GET is done, this fix can be reverted safely. Fixes: 4cd614841c06 ("mm: migration: fix possible do_pages_stat_array racing with memory offline") Signed-off-by: Haiyue Wang --- mm/migrate.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 6a1597c92261..581dfaad9257 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1848,6 +1848,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, for (i = 0; i < nr_pages; i++) { unsigned long addr = (unsigned long)(*pages); + unsigned int foll_flags = FOLL_DUMP; struct vm_area_struct *vma; struct page *page; int err = -EFAULT; @@ -1856,8 +1857,12 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (!vma) goto set_status; + /* Not all huge page follow APIs support 'FOLL_GET' */ + if (!is_vm_hugetlb_page(vma)) + foll_flags |= FOLL_GET; + /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); + page = follow_page(vma, addr, foll_flags); err = PTR_ERR(page); if (IS_ERR(page)) @@ -1865,7 +1870,8 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (page && !is_zone_device_page(page)) { err = page_to_nid(page); - put_page(page); + if (foll_flags & FOLL_GET) + put_page(page); } else { err = -ENOENT; }