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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F1D97C10F14 for ; Thu, 10 Oct 2019 14:12:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C996F206A1 for ; Thu, 10 Oct 2019 14:12:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726383AbfJJOMG (ORCPT ); Thu, 10 Oct 2019 10:12:06 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46580 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726084AbfJJOMF (ORCPT ); Thu, 10 Oct 2019 10:12:05 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 55C343084032; Thu, 10 Oct 2019 14:12:05 +0000 (UTC) Received: from t460s.redhat.com (ovpn-117-218.ams2.redhat.com [10.36.117.218]) by smtp.corp.redhat.com (Postfix) with ESMTP id 220B75C1B2; Thu, 10 Oct 2019 14:12:00 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, David Hildenbrand , Greg Kroah-Hartman , "Rafael J. Wysocki" , Michal Hocko , Andrew Morton Subject: [PATCH v1] drivers/base/memory.c: Don't access uninitialized memmaps in soft_offline_page_store() Date: Thu, 10 Oct 2019 16:12:00 +0200 Message-Id: <20191010141200.8985-1-david@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Thu, 10 Oct 2019 14:12:05 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Uninitialized memmaps contain garbage and in the worst case trigger kernel BUGs, especially with CONFIG_PAGE_POISONING. They should not get touched. Right now, when trying to soft-offline a PFN that resides on a memory block that was never onlined, one gets a misleading error with CONFIG_PAGE_POISONING: :/# echo 5637144576 > /sys/devices/system/memory/soft_offline_page [ 23.097167] soft offline: 0x150000 page already poisoned But the actual result depends on the garbage in the memmap. soft_offline_page() can only work with online pages, it returns -EIO in case of ZONE_DEVICE. Make sure to only forward pages that are online (iow, managed by the buddy) and, therefore, have an initialized memmap. Add a check against pfn_to_online_page() and similarly return -EIO. Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") # visible after d0dc12e86b319 Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Michal Hocko Cc: Andrew Morton Signed-off-by: David Hildenbrand --- drivers/base/memory.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 6bea4f3f8040..55907c27075b 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -540,6 +540,9 @@ static ssize_t soft_offline_page_store(struct device *dev, pfn >>= PAGE_SHIFT; if (!pfn_valid(pfn)) return -ENXIO; + /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */ + if (!pfn_to_online_page(pfn)) + return -EIO; ret = soft_offline_page(pfn_to_page(pfn), 0); return ret == 0 ? count : ret; } -- 2.21.0