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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 488F3C433E9 for ; Fri, 5 Feb 2021 02:33:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E191164FC3 for ; Fri, 5 Feb 2021 02:33:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230218AbhBECdI (ORCPT ); Thu, 4 Feb 2021 21:33:08 -0500 Received: from mail.kernel.org ([198.145.29.99]:45698 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230205AbhBECdF (ORCPT ); Thu, 4 Feb 2021 21:33:05 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2F46464FBA; Fri, 5 Feb 2021 02:32:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1612492341; bh=end8ZKS4T7ptw5SR9wK/aXEzwYfzKhcMOz6jwiV+54s=; h=Date:From:To:Subject:In-Reply-To:From; b=waFML216VtBpZWEimUzOBFNdrjCq3s9ulmhUoyQKiQuZBJ4j77lg5Nl0JGSsHp+HT xPdJFqckQJ2j5WCZH4x166L6WRWymBRuhGP35+pDrHmrsO2tGsuMZB4eZx0mgVdtfE fUTlRaaWDodGhak9sgWyYjRZ2+sDT+StLtzVu7HQ= Date: Thu, 04 Feb 2021 18:32:20 -0800 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mgorman@techsingularity.net, mm-commits@vger.kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org, vbabka@suse.cz, wu-yan@tcl.com Subject: [patch 06/18] mm, compaction: move high_pfn to the for loop scope Message-ID: <20210205023220.Bma4nzI32%akpm@linux-foundation.org> In-Reply-To: <20210204183135.e123f0d6027529f2cf500cf2@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Rokudo Yan Subject: mm, compaction: move high_pfn to the for loop scope 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(). Link: http://lkml.kernel.org/r/20190118175136.31341-12-mgorman@techsingularity.net Link: https://lkml.kernel.org/r/20210112094720.1238444-1-wu-yan@tcl.com Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a migration target") Signed-off-by: Rokudo Yan Acked-by: Mel Gorman Acked-by: Vlastimil Babka Cc: Signed-off-by: Andrew Morton --- mm/compaction.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/mm/compaction.c~mm-compaction-move-high_pfn-to-the-for-loop-scope +++ a/mm/compaction.c @@ -1342,7 +1342,7 @@ fast_isolate_freepages(struct compact_co { unsigned int limit = min(1U, freelist_scan_limit(cc) >> 1); unsigned int nr_scanned = 0; - unsigned long low_pfn, min_pfn, high_pfn = 0, highest = 0; + unsigned long low_pfn, min_pfn, highest = 0; unsigned long nr_isolated = 0; unsigned long distance; struct page *page = NULL; @@ -1387,6 +1387,7 @@ fast_isolate_freepages(struct compact_co struct page *freepage; unsigned long flags; unsigned int order_scanned = 0; + unsigned long high_pfn = 0; if (!area->nr_free) continue; _