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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 65D7DCA9EC0 for ; Tue, 29 Oct 2019 02:29:28 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2213E21479 for ; Tue, 29 Oct 2019 02:29:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2213E21479 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ACECA6B0005; Mon, 28 Oct 2019 22:29:27 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A7EDA6B0006; Mon, 28 Oct 2019 22:29:27 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 995206B0007; Mon, 28 Oct 2019 22:29:27 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0046.hostedemail.com [216.40.44.46]) by kanga.kvack.org (Postfix) with ESMTP id 70FA56B0005 for ; Mon, 28 Oct 2019 22:29:27 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id EAB7A180AD81A for ; Tue, 29 Oct 2019 02:29:26 +0000 (UTC) X-FDA: 76095240732.24.coal10_17d6ff8642c40 X-HE-Tag: coal10_17d6ff8642c40 X-Filterd-Recvd-Size: 7358 Received: from huawei.com (szxga04-in.huawei.com [45.249.212.190]) by imf08.hostedemail.com (Postfix) with ESMTP for ; Tue, 29 Oct 2019 02:29:23 +0000 (UTC) Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id DAB8AE8E86E3488C2F96; Tue, 29 Oct 2019 10:29:19 +0800 (CST) Received: from [127.0.0.1] (10.133.219.218) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.439.0; Tue, 29 Oct 2019 10:29:18 +0800 Message-ID: <5DB7A3FE.3040902@huawei.com> Date: Tue, 29 Oct 2019 10:29:18 +0800 From: zhong jiang User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:12.0) Gecko/20120428 Thunderbird/12.0.1 MIME-Version: 1.0 To: David Hildenbrand CC: , , , , , Minchan Kim Subject: Re: [PATCH] mm: fix unevictable page reclaim when calling madvise_pageout References: <1572275317-63910-1-git-send-email-zhongjiang@huawei.com> <3ac2e87d-2899-ab17-8b0b-8aa6a5035d4a@redhat.com> <5DB70D17.9040108@huawei.com> <991592a5-e8a3-f392-f330-e2e1b582fb6a@redhat.com> <4697f081-933b-6620-8c94-4b8c6a6f661d@redhat.com> In-Reply-To: <4697f081-933b-6620-8c94-4b8c6a6f661d@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.133.219.218] X-CFilter-Loop: Reflected X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 2019/10/29 0:15, David Hildenbrand wrote: > On 28.10.19 17:07, David Hildenbrand wrote: >> On 28.10.19 16:45, zhong jiang wrote: >>> On 2019/10/28 23:27, David Hildenbrand wrote: >>>> On 28.10.19 16:08, zhong jiang wrote: >>>>> Recently, I hit the following issue when running in the upstream. >>>>> >>>>> kernel BUG at mm/vmscan.c:1521! >>>>> invalid opcode: 0000 [#1] SMP KASAN PTI >>>>> CPU: 0 PID: 23385 Comm: syz-executor.6 Not tainted 5.4.0-rc4+ #1 >>>>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 >>>>> RIP: 0010:shrink_page_list+0x12b6/0x3530 mm/vmscan.c:1521 >>>>> Code: de f5 ff ff e8 ab 79 eb ff 4c 89 f7 e8 43 33 0d 00 e9 cc f5 ff ff e8 99 79 eb ff 48 c7 c6 a0 34 2b a0 4c 89 f7 e8 1a 4d 05 00 <0f> 0b e8 83 79 eb ff 48 89 d8 48 c1 e8 03 42 80 3c 38 00 0f 85 74 >>>>> RSP: 0018:ffff88819a3df5a0 EFLAGS: 00010286 >>>>> RAX: 0000000000040000 RBX: ffffea00061c3980 RCX: ffffffff814fba36 >>>>> RDX: 00000000000056f7 RSI: ffffc9000c02c000 RDI: ffff8881f70268cc >>>>> RBP: ffff88819a3df898 R08: ffffed103ee05de0 R09: ffffed103ee05de0 >>>>> R10: 0000000000000001 R11: ffffed103ee05ddf R12: ffff88819a3df6f0 >>>>> R13: ffff88819a3df6f0 R14: ffffea00061c3980 R15: dffffc0000000000 >>>>> FS: 00007f21b9d8e700(0000) GS:ffff8881f7000000(0000) knlGS:0000000000000000 >>>>> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >>>>> CR2: 0000001b2d621000 CR3: 00000001c8c46004 CR4: 00000000007606f0 >>>>> DR0: 0000000020000140 DR1: 0000000000000000 DR2: 0000000000000000 >>>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 >>>>> PKRU: 55555554 >>>>> Call Trace: >>>>> reclaim_pages+0x499/0x800 mm/vmscan.c:2188 >>>>> madvise_cold_or_pageout_pte_range+0x58a/0x710 mm/madvise.c:453 >>>>> walk_pmd_range mm/pagewalk.c:53 [inline] >>>>> walk_pud_range mm/pagewalk.c:112 [inline] >>>>> walk_p4d_range mm/pagewalk.c:139 [inline] >>>>> walk_pgd_range mm/pagewalk.c:166 [inline] >>>>> __walk_page_range+0x45a/0xc20 mm/pagewalk.c:261 >>>>> walk_page_range+0x179/0x310 mm/pagewalk.c:349 >>>>> madvise_pageout_page_range mm/madvise.c:506 [inline] >>>>> madvise_pageout+0x1f0/0x330 mm/madvise.c:542 >>>>> madvise_vma mm/madvise.c:931 [inline] >>>>> __do_sys_madvise+0x7d2/0x1600 mm/madvise.c:1113 >>>>> do_syscall_64+0x9f/0x4c0 arch/x86/entry/common.c:290 >>>>> entry_SYSCALL_64_after_hwframe+0x49/0xbe >>>>> >>>>> madvise_pageout access the specified range of the vma and isolate >>>>> them, then run shrink_page_list to reclaim the memory. But It also >>>>> isolate the unevictable page to reclaim. Hence, we can catch the >>>>> cases in shrink_page_list. >>>>> >>>>> We can fix it by preventing unevictable page from isolating. >>>>> Another way to fix the issue by removing the condition of >>>>> BUG_ON(PageUnevictable(page)) in shrink_page_list. I think it >>>>> is better to use the latter. Because We has taken the unevictable >>>>> page and skip it into account in shrink_page_list. >>>> I really don't understand the last sentence. Looks like >>>> something got messed up :) >>> I mean that we will check the page_evictable(page) in shrink_page_list, >>> if it is unevictable page, we will put the page back to correct lru. >>> >>> Based on the condition, I make the choice. It seems to more simpler.:-) >>> >>> Thanks, >>> zhong jiang >>>> >>>>> Signed-off-by: zhong jiang >>>>> --- >>>>> mm/vmscan.c | 2 +- >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>>> >>>>> diff --git a/mm/vmscan.c b/mm/vmscan.c >>>>> index f7d1301..1c6e959 100644 >>>>> --- a/mm/vmscan.c >>>>> +++ b/mm/vmscan.c >>>>> @@ -1524,7 +1524,7 @@ static unsigned long shrink_page_list(struct list_head *page_list, >>>>> unlock_page(page); >>>>> keep: >>>>> list_add(&page->lru, &ret_pages); >>>>> - VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page), page); >>>>> + VM_BUG_ON_PAGE(PageLRU(page), page); >>>> So, this comes from >>>> >>>> commit b291f000393f5a0b679012b39d79fbc85c018233 >>>> Author: Nick Piggin >>>> Date: Sat Oct 18 20:26:44 2008 -0700 >>>> >>>> mlock: mlocked pages are unevictable >>>> Make sure that mlocked pages also live on the unevictable LRU, so kswapd >>>> will not scan them over and over again. >>>> >>>> >>>> That patch is fairly old. How come we can suddenly trigger this? >>>> Which commit is responsible for that? Was it always broken? >>>> >>>> I can see that >>>> >>>> commit ad6b67041a45497261617d7a28b15159b202cb5a >>>> Author: Minchan Kim >>>> Date: Wed May 3 14:54:13 2017 -0700 >>>> >>>> mm: remove SWAP_MLOCK in ttu >>>> >>>> Performed some changes in that area. But also some time ago. >>> I think the following patch introduce the issue. >>> >>> commit 1a4e58cce84ee88129d5d49c064bd2852b481357 >>> Author: Minchan Kim >>> Date: Wed Sep 25 16:49:15 2019 -0700 >>> >>> mm: introduce MADV_PAGEOUT >>> >>> When a process expects no accesses to a certain memory range for a long >>> >> >> CCing Minchan Kim then. >> >> If this is indeed the introducing patch, you probably reference that >> patch in your cover mail somehow. (Fixes: does not apply until upstream) >> >> I am absolutely no expert on vmscan.c, so I'm afraid I can't really >> comment on the details. >> > > Oh, and just wondering, is this the same BUG as in > > https://lkml.org/lkml/2019/8/2/1506 > > Where a fix has been proposed? The fix does not seem to be in next/master yet. > > (I just realized that it is already upstream so "Fixes: 1a4e58cce84e ("mm: introduce MADV_PAGEOUT")) applies. > > > I think that is not same issue. thannks