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=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 38750C4332B for ; Mon, 18 Jan 2021 09:57:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 081B922512 for ; Mon, 18 Jan 2021 09:57:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389313AbhARJvU (ORCPT ); Mon, 18 Jan 2021 04:51:20 -0500 Received: from outbound-smtp47.blacknight.com ([46.22.136.64]:40527 "EHLO outbound-smtp47.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389070AbhARJnM (ORCPT ); Mon, 18 Jan 2021 04:43:12 -0500 Received: from mail.blacknight.com (pemlinmail01.blacknight.ie [81.17.254.10]) by outbound-smtp47.blacknight.com (Postfix) with ESMTPS id 76CFFFBF03 for ; Mon, 18 Jan 2021 09:42:19 +0000 (GMT) Received: (qmail 26312 invoked from network); 18 Jan 2021 09:42:19 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.22.4]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 18 Jan 2021 09:42:19 -0000 Date: Mon, 18 Jan 2021 09:42:17 +0000 From: Mel Gorman To: Rokudo Yan Cc: akpm@linux-foundation.org, aarcange@redhat.com, haiwang.fu@tcl.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, rientjes@google.com, tang.ding@tcl.com, vbabka@suse.cz, xiushui.ye@tcl.com Subject: Re: [PATCH] mm, compaction: move high_pfn to the for loop scope. Message-ID: <20210118094217.GQ3592@techsingularity.net> References: <20210112142711.b82cf36abaa7ff04773e212f@linux-foundation.org> <20210118074126.1838139-1-wu-yan@tcl.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20210118074126.1838139-1-wu-yan@tcl.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 18, 2021 at 03:41:26PM +0800, Rokudo Yan wrote: > In fast_isolate_freepages, high_pfn will be used if a prefered one(PFN >= low_fn) not found. But the high_pfn > is not reset before searching an free area, so when it was used as freepage, it may from another free area searched before. > And move_freelist_head(freelist, freepage) will have unexpected behavior(eg. corrupt the MOVABLE freelist) > > Unable to handle kernel paging request at virtual address dead000000000200 > Mem abort info: > ESR = 0x96000044 > Exception class = DABT (current EL), IL = 32 bits > SET = 0, FnV = 0 > EA = 0, S1PTW = 0 > Data abort info: > ISV = 0, ISS = 0x00000044 > CM = 0, WnR = 1 > [dead000000000200] address between user and kernel address ranges > > -000|list_cut_before(inline) > -000|move_freelist_head(inline) > -000|fast_isolate_freepages(inline) > -000|isolate_freepages(inline) > -000|compaction_alloc(?, ?) > -001|unmap_and_move(inline) > -001|migrate_pages([NSD:0xFFFFFF80088CBBD0] from = 0xFFFFFF80088CBD88, [NSD:0xFFFFFF80088CBBC8] get_new_p > -002|__read_once_size(inline) > -002|static_key_count(inline) > -002|static_key_false(inline) > -002|trace_mm_compaction_migratepages(inline) > -002|compact_zone(?, [NSD:0xFFFFFF80088CBCB0] capc = 0x0) > -003|kcompactd_do_work(inline) > -003|kcompactd([X19] p = 0xFFFFFF93227FBC40) > -004|kthread([X20] _create = 0xFFFFFFE1AFB26380) > -005|ret_from_fork(asm) > ---|end of frame > > The issue was reported on an smart phone product with 6GB ram and 3GB zram as swap device. > > This patch fixes the issue by reset high_pfn before searching each free area, which ensure > freepage and freelist match when call move_freelist_head in fast_isolate_freepages(). > > Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a migration target") > > Signed-off-by: Rokudo Yan Other than a fixes line, I do not think this changed so my previous Ack still applies Acked-by: Mel Gorman -- Mel Gorman SUSE Labs