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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS 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 75835C433DB for ; Tue, 12 Jan 2021 22:28:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2015D23120 for ; Tue, 12 Jan 2021 22:28:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394562AbhALW2H (ORCPT ); Tue, 12 Jan 2021 17:28:07 -0500 Received: from mail.kernel.org ([198.145.29.99]:57816 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731556AbhALW1x (ORCPT ); Tue, 12 Jan 2021 17:27:53 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id F3C9923120; Tue, 12 Jan 2021 22:27:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1610490432; bh=xxQ8MfqyAklnD0AulIQNNMFIA3u/PTYanCkpNaTjiYA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=pU67xGihUoOUdUglxIEJzItDAKZw0YIAbhe1AHc4leSkc/6MSGmkv58lLqZunhlXn PS7FupmFacuRuwH30+MHwSnvmGG+n0ouuipCw+mPFe6kSc51PAzAL//1E2M/nG8TTy 1rNSX5qGFw+HkLTMJ40Nzl4Boknm7e5KZeg6F+cY= Date: Tue, 12 Jan 2021 14:27:11 -0800 From: Andrew Morton To: Rokudo Yan Cc: , , , , , , , , Subject: Re: [PATCH] mm, compaction: move high_pfn to the for loop scope. Message-Id: <20210112142711.b82cf36abaa7ff04773e212f@linux-foundation.org> In-Reply-To: <20210112094720.1238444-1-wu-yan@tcl.com> References: <20210112091041.GJ3592@techsingularity.net> <20210112094720.1238444-1-wu-yan@tcl.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 12 Jan 2021 17:47:20 +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(). > > Link: http://lkml.kernel.org/r/20190118175136.31341-12-mgorman@techsingularity.net > Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a migration target") Could you please send a Signed-off-by: for this patch, as per Documentation/process/submitting-patches.rst?