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=-11.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT 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 78312C433DB for ; Tue, 12 Jan 2021 05:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2029022CB1 for ; Tue, 12 Jan 2021 05:26:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388716AbhALF0a (ORCPT ); Tue, 12 Jan 2021 00:26:30 -0500 Received: from bgp198.corpemail.net ([222.73.254.198]:13758 "EHLO bgp198.corpemail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732060AbhALF0a (ORCPT ); Tue, 12 Jan 2021 00:26:30 -0500 Received: from ([183.47.25.45]) by support.corp-email.com ((LNX1044)) with ASMTP (SSL) id FWG00039; Tue, 12 Jan 2021 13:20:39 +0800 Received: from GCY-EXS-15.TCL.com (10.74.128.165) by GCY-EXS-05.TCL.com (10.74.128.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Tue, 12 Jan 2021 13:20:40 +0800 Received: from localhost.localdomain (172.16.34.38) by GCY-EXS-15.TCL.com (10.74.128.165) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Tue, 12 Jan 2021 13:20:24 +0800 From: Rokudo Yan To: CC: , , , , , , , , , Subject: [PATCH] mm, compaction: make sure we isolate a valid freepage when high_pfn is used Date: Tue, 12 Jan 2021 13:19:55 +0800 Message-ID: <20210112051955.1221914-1-wu-yan@tcl.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <81e45dc0-c107-015b-e167-19d7ca4b6374@suse.cz> References: <81e45dc0-c107-015b-e167-19d7ca4b6374@suse.cz> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [172.16.34.38] X-ClientProxiedBy: GCY-EXS-01.TCL.com (10.74.128.151) To GCY-EXS-15.TCL.com (10.74.128.165) tUid: 20211121320399c8403f36c678069a60c87198e36496d X-Abuse-Reports-To: service@corp-email.com Abuse-Reports-To: service@corp-email.com X-Complaints-To: service@corp-email.com X-Report-Abuse-To: service@corp-email.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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/1558711908-15688-1-git-send-email-suzuki.poulose@arm.com Fixes: 5a811889de10f1eb ("mm, compaction: use free lists to quickly locate a migration target") --- mm/compaction.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/compaction.c b/mm/compaction.c index cc1a7f600a86..6754229f4213 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1352,6 +1352,7 @@ fast_isolate_freepages(struct compact_control *cc) if (!area->nr_free) continue; + high_pfn = 0; spin_lock_irqsave(&cc->zone->lock, flags); freelist = &area->free_list[MIGRATE_MOVABLE]; list_for_each_entry_reverse(freepage, freelist, lru) { -- 2.25.1