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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 5835ACA9EAD for ; Sat, 19 Oct 2019 03:19:20 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 14EF9222C6 for ; Sat, 19 Oct 2019 03:19:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="hzNv8r/7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 14EF9222C6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BF6518E0006; Fri, 18 Oct 2019 23:19:19 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BA6CC8E0003; Fri, 18 Oct 2019 23:19:19 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ABD548E0006; Fri, 18 Oct 2019 23:19:19 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0114.hostedemail.com [216.40.44.114]) by kanga.kvack.org (Postfix) with ESMTP id 8B8178E0003 for ; Fri, 18 Oct 2019 23:19:19 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id E37A0180ACEFB for ; Sat, 19 Oct 2019 03:19:18 +0000 (UTC) X-FDA: 76059078396.22.brush54_1713642594a37 X-HE-Tag: brush54_1713642594a37 X-Filterd-Recvd-Size: 3426 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Sat, 19 Oct 2019 03:19:18 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 335E7222C2; Sat, 19 Oct 2019 03:19:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571455157; bh=OEAIZ1PKxau5YvsqOA6tZGND2Xfq1vBQnB7VIx7SxoE=; h=Date:From:To:Subject:From; b=hzNv8r/7XP2wY8CSxOq2uf2SshJvoN9CF63h+l3kgpV+iHDwCE7/PZwlWwqnd4vTq 1VWYMBTZCsDgukLTUhhtFtn660v3rk5JyiOQR0eSXEhhrXsmzQIfzrHLyUct9do2RZ cQzQREZxZRzo3w7FD+W9UwaR92+a+zpQWjKvAVh4= Date: Fri, 18 Oct 2019 20:19:16 -0700 From: akpm@linux-foundation.org To: akpm@linux-foundation.org, david@redhat.com, gregkh@linuxfoundation.org, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, n-horiguchi@ah.jp.nec.com, rafael@kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: [patch 01/26] drivers/base/memory.c: don't access uninitialized memmaps in soft_offline_page_store() Message-ID: <20191019031916.Ux-StDx4F%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: David Hildenbrand Subject: drivers/base/memory.c: don't access uninitialized memmaps in soft_offline_page_store() 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. Link: http://lkml.kernel.org/r/20191010141200.8985-1-david@redhat.com Fixes: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] Signed-off-by: David Hildenbrand Acked-by: Naoya Horiguchi Acked-by: Michal Hocko Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: [4.13+] Signed-off-by: Andrew Morton --- drivers/base/memory.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/base/memory.c~drivers-base-memoryc-dont-access-uninitialized-memmaps-in-soft_offline_page_store +++ a/drivers/base/memory.c @@ -540,6 +540,9 @@ static ssize_t soft_offline_page_store(s 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; } _