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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54643C433EF for ; Thu, 28 Apr 2022 17:25:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id CAE5F6B00BC; Thu, 28 Apr 2022 13:25:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C5E118D0015; Thu, 28 Apr 2022 13:25:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B27426B00C0; Thu, 28 Apr 2022 13:25:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.27]) by kanga.kvack.org (Postfix) with ESMTP id 9F4076B00BC for ; Thu, 28 Apr 2022 13:25:47 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 65C782928B for ; Thu, 28 Apr 2022 17:25:47 +0000 (UTC) X-FDA: 79406965134.04.8792CF5 Received: from mail-pj1-f44.google.com (mail-pj1-f44.google.com [209.85.216.44]) by imf22.hostedemail.com (Postfix) with ESMTP id 1A991C0054 for ; Thu, 28 Apr 2022 17:25:45 +0000 (UTC) Received: by mail-pj1-f44.google.com with SMTP id r9so4900251pjo.5 for ; Thu, 28 Apr 2022 10:25:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=VCwam7UiUNOXhElbv2jko1D22lHmNSK/U551dYCHJBk=; b=kb2gXGO0dOiHelquCwPSsvA81OokVqaYnDdu+PCdW9ZS0DatM5QQUDG0tmfeaQmLzo 4CJS+I78m6sSb3rqc15C4CJpW2lQp40Cpec+y1RhaGZCBz9izEaUCWIt8S4Lw1ZjOsrD 46UMZnHk/jDIwkEIWMmBS6cSAo5Vz5iqQ7RyBUr0ZjXjbBmHCERFX0NjjvMvBmcSlihu iX+ttzi3Z8eLHazNtGWX7lX1ai7smZXZg9JBSjDzJIUUbJezyAR6Qfi9ZCU+7kVRPzx2 3HNwguIMh1tbxiEnJAwiuc3M1jnQR566x2JDe8I+hp5rp3OdFSKMTN9lSdEavqnco0i0 fvzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=VCwam7UiUNOXhElbv2jko1D22lHmNSK/U551dYCHJBk=; b=Ds6O5Zlqze7QoKKLynJ+aRHp+L5418soyprecOWKGHqgVeUI/7DoFEu+a4P8ae6UvN gLr+q1ok6AHNhqEA8+CPaIlhauyNYOWgMZNJBsUlWQu76+fDaaWmx2sx63XO26JcSXDU 1JesEB40RXsKF6hVwe/2kJZn9r58wRo8qWQS4e1mkNc3d/xni1dH2cQS+E6jo/Mfe0vQ B4HjL6F9NmNXP6JLBmOBGWNXuwa3OOK4FgqypYkkSxrOSHjjB9bb3YF8heyLDyIC4o5F jDuIw+xoTjwNuKg+oslN2w/4/JzzYnTshEP7AdZv90MsAAk88exEzZ/Hg+Gui2x09aed gywQ== X-Gm-Message-State: AOAM531GNu/c5taWDYx6GPRDkSAc6HBFnz2zad2v0tinzxAB4VW9uL/X ZnfDUzO4xWN/QbeAdc9ZQ2C+hUc3T/eHftCwy8A= X-Google-Smtp-Source: ABdhPJx/6Wrux0hAoIpHbzr0izmaFGDh3pXpcrD2VvY0Ekjt5BdumhW+HSUTcUf/+427d9ui4qoZtrF+a9c0tOAKRCg= X-Received: by 2002:a17:902:d5c3:b0:154:c472:de80 with SMTP id g3-20020a170902d5c300b00154c472de80mr34345864plh.87.1651166745857; Thu, 28 Apr 2022 10:25:45 -0700 (PDT) MIME-Version: 1.0 References: <20220427053220.719866-1-naoya.horiguchi@linux.dev> In-Reply-To: <20220427053220.719866-1-naoya.horiguchi@linux.dev> From: Yang Shi Date: Thu, 28 Apr 2022 10:25:33 -0700 Message-ID: Subject: Re: [PATCH v2] mm/hwpoison: use pr_err() instead of dump_page() in get_any_page() To: Naoya Horiguchi Cc: Linux MM , Matthew Wilcox , Miaohe Lin , Christoph Hellwig , Andrew Morton , John Hubbard , Jason Gunthorpe , William Kucharski , Naoya Horiguchi , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: e9kmgpjcgdfmbpcbz6y98oifob4f6jpe X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 1A991C0054 Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=kb2gXGO0; spf=pass (imf22.hostedemail.com: domain of shy828301@gmail.com designates 209.85.216.44 as permitted sender) smtp.mailfrom=shy828301@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: X-HE-Tag: 1651166745-287346 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 Tue, Apr 26, 2022 at 10:32 PM Naoya Horiguchi wrote: > > From: Naoya Horiguchi > > The following VM_BUG_ON_FOLIO() is triggered when memory error event > happens on the (thp/folio) pages which are about to be freed: > > [ 1160.232771] page:00000000b36a8a0f refcount:1 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x16a000 > [ 1160.236916] page:00000000b36a8a0f refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x16a000 > [ 1160.240684] flags: 0x57ffffc0800000(hwpoison|node=1|zone=2|lastcpupid=0x1fffff) > [ 1160.243458] raw: 0057ffffc0800000 dead000000000100 dead000000000122 0000000000000000 > [ 1160.246268] raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 > [ 1160.249197] page dumped because: VM_BUG_ON_FOLIO(!folio_test_large(folio)) > [ 1160.251815] ------------[ cut here ]------------ > [ 1160.253438] kernel BUG at include/linux/mm.h:788! > [ 1160.256162] invalid opcode: 0000 [#1] PREEMPT SMP PTI > [ 1160.258172] CPU: 2 PID: 115368 Comm: mceinj.sh Tainted: G E 5.18.0-rc1-v5.18-rc1-220404-2353-005-g83111+ #3 > [ 1160.262049] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014 > [ 1160.265103] RIP: 0010:dump_page.cold+0x27e/0x2bd > [ 1160.266757] Code: fe ff ff 48 c7 c6 81 f1 5a 98 e9 4c fe ff ff 48 c7 c6 a1 95 59 98 e9 40 fe ff ff 48 c7 c6 50 bf 5a 98 48 89 ef e8 9d 04 6d ff <0f> 0b 41 f7 c4 ff 0f 00 00 0f 85 9f fd ff ff 49 8b 04 24 a9 00 00 > [ 1160.273180] RSP: 0018:ffffaa2c4d59fd18 EFLAGS: 00010292 > [ 1160.274969] RAX: 000000000000003e RBX: 0000000000000001 RCX: 0000000000000000 > [ 1160.277263] RDX: 0000000000000001 RSI: ffffffff985995a1 RDI: 00000000ffffffff > [ 1160.279571] RBP: ffffdc9c45a80000 R08: 0000000000000000 R09: 00000000ffffdfff > [ 1160.281794] R10: ffffaa2c4d59fb08 R11: ffffffff98940d08 R12: ffffdc9c45a80000 > [ 1160.283920] R13: ffffffff985b6f94 R14: 0000000000000000 R15: ffffdc9c45a80000 > [ 1160.286641] FS: 00007eff54ce1740(0000) GS:ffff99c67bd00000(0000) knlGS:0000000000000000 > [ 1160.289498] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 1160.291106] CR2: 00005628381a5f68 CR3: 0000000104712003 CR4: 0000000000170ee0 > [ 1160.293031] Call Trace: > [ 1160.293724] > [ 1160.294334] get_hwpoison_page+0x47d/0x570 > [ 1160.295474] memory_failure+0x106/0xaa0 > [ 1160.296474] ? security_capable+0x36/0x50 > [ 1160.297524] hard_offline_page_store+0x43/0x80 > [ 1160.298684] kernfs_fop_write_iter+0x11c/0x1b0 > [ 1160.299829] new_sync_write+0xf9/0x160 > [ 1160.300810] vfs_write+0x209/0x290 > [ 1160.301835] ksys_write+0x4f/0xc0 > [ 1160.302718] do_syscall_64+0x3b/0x90 > [ 1160.303664] entry_SYSCALL_64_after_hwframe+0x44/0xae > [ 1160.304981] RIP: 0033:0x7eff54b018b7 > > As shown in the RIP address, this VM_BUG_ON in folio_entire_mapcount() is > called from dump_page("hwpoison: unhandlable page") in get_any_page(). > The below explains the mechanism of the race: > > CPU 0 CPU 1 > > memory_failure > get_hwpoison_page > get_any_page > dump_page > compound = PageCompound > free_pages_prepare > page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP > folio_entire_mapcount > VM_BUG_ON_FOLIO(!folio_test_large(folio)) > > So replace dump_page() with safer one, pr_err(). > > Fixes: 74e8ee4708a8 ("mm: Turn head_compound_mapcount() into folio_entire_mapcount()") > Signed-off-by: Naoya Horiguchi > --- > ChangeLog v1 -> v2: > - v1: https://lore.kernel.org/linux-mm/20220414235950.840409-1-naoya.horiguchi@linux.dev/T/#u > - update caller side instead of changing dump_page(). > --- > mm/memory-failure.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index 35e11d6bea4a..0e1453514a2b 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -1270,7 +1270,7 @@ static int get_any_page(struct page *p, unsigned long flags) > } > out: > if (ret == -EIO) > - dump_page(p, "hwpoison: unhandlable page"); > + pr_err("Memory failure: %#lx: unhandlable page.\n", page_to_pfn(p)); I think dump_page() is helpful to tell the users more information about the unhandlable page, I'm ok with this fix for now, but should we consider having a memory failure safe dump_page() in the future? > > return ret; > } > -- > 2.25.1 > >