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=-9.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 CF26FC43381 for ; Sat, 23 Feb 2019 21:13:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AE8A20675 for ; Sat, 23 Feb 2019 21:13:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550956437; bh=H288oKZ7xm1LNXoh5JN36UfOyP8XY+Z8q8XgKvZYOTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=H4Gowi0EzNB4qNnKSK37UW6S8zZ5VrB85zyt00yp2KN8HRdxdau+f9GhJCS9nyPXn s460C2fd6YEOMsqett2Gw8UtGN27PsgwaZi7VFDyYFYE0dNWeUjSNDZPRHCnNn9X7j G/HCz28zIZSgH2698S//4IgzijzuWg955g5fGilc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730075AbfBWVN4 (ORCPT ); Sat, 23 Feb 2019 16:13:56 -0500 Received: from mail.kernel.org ([198.145.29.99]:47996 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729991AbfBWVLa (ORCPT ); Sat, 23 Feb 2019 16:11:30 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC48520861; Sat, 23 Feb 2019 21:11:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550956289; bh=H288oKZ7xm1LNXoh5JN36UfOyP8XY+Z8q8XgKvZYOTY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u4Yz+TIX1fDftVHsdGT7QqA+PNpqq7ZW1UEJShWAfn0WLs7HHcdEXkQt6OrXEVBj+ qT+C/Wx2/X3E31++SOxQX9rY53FJUUv4qsTzBQupkfEgkvVd5ypD/gkx80S3APPM7T ZOEyntEj4CiyYkvRh1dBVYmEqu+fg+SZzneP+QzU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Mikhail Zaslonko , Michal Hocko , Heiko Carstens , Martin Schwidefsky , Mikhail Gavrilov , Pavel Tatashin , Andrew Morton , Linus Torvalds , Sasha Levin , linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.4 23/26] mm, memory_hotplug: test_pages_in_a_zone do not pass the end of zone Date: Sat, 23 Feb 2019 16:10:44 -0500 Message-Id: <20190223211047.202725-23-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190223211047.202725-1-sashal@kernel.org> References: <20190223211047.202725-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mikhail Zaslonko [ Upstream commit 24feb47c5fa5b825efb0151f28906dfdad027e61 ] If memory end is not aligned with the sparse memory section boundary, the mapping of such a section is only partly initialized. This may lead to VM_BUG_ON due to uninitialized struct pages access from test_pages_in_a_zone() function triggered by memory_hotplug sysfs handlers. Here are the the panic examples: CONFIG_DEBUG_VM_PGFLAGS=y kernel parameter mem=2050M -------------------------- page:000003d082008000 is uninitialized and poisoned page dumped because: VM_BUG_ON_PAGE(PagePoisoned(p)) Call Trace: test_pages_in_a_zone+0xde/0x160 show_valid_zones+0x5c/0x190 dev_attr_show+0x34/0x70 sysfs_kf_seq_show+0xc8/0x148 seq_read+0x204/0x480 __vfs_read+0x32/0x178 vfs_read+0x82/0x138 ksys_read+0x5a/0xb0 system_call+0xdc/0x2d8 Last Breaking-Event-Address: test_pages_in_a_zone+0xde/0x160 Kernel panic - not syncing: Fatal exception: panic_on_oops Fix this by checking whether the pfn to check is within the zone. [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Link: http://lkml.kernel.org/r/20190128144506.15603-3-mhocko@kernel.org [mhocko@suse.com: separated this change from http://lkml.kernel.org/r/20181105150401.97287-2-zaslonko@linux.ibm.com] Signed-off-by: Michal Hocko Signed-off-by: Mikhail Zaslonko Tested-by: Mikhail Gavrilov Reviewed-by: Oscar Salvador Tested-by: Gerald Schaefer Cc: Heiko Carstens Cc: Martin Schwidefsky Cc: Mikhail Gavrilov Cc: Pavel Tatashin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/memory_hotplug.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 153acbf5f83db..804cbfe9132dd 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1399,6 +1399,9 @@ int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn, i++; if (i == MAX_ORDER_NR_PAGES) continue; + /* Check if we got outside of the zone */ + if (zone && !zone_spans_pfn(zone, pfn + i)) + return 0; page = pfn_to_page(pfn + i); if (zone && page_zone(page) != zone) return 0; -- 2.19.1