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 5D68EC433EF for ; Wed, 27 Apr 2022 21:15:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E09336B0073; Wed, 27 Apr 2022 17:15:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DB78A6B0074; Wed, 27 Apr 2022 17:15:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C58C76B0075; Wed, 27 Apr 2022 17:15:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id B4B966B0073 for ; Wed, 27 Apr 2022 17:15:55 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 78196216B7 for ; Wed, 27 Apr 2022 21:15:55 +0000 (UTC) X-FDA: 79403916270.06.502C014 Received: from mail-pf1-f171.google.com (mail-pf1-f171.google.com [209.85.210.171]) by imf04.hostedemail.com (Postfix) with ESMTP id 9522240064 for ; Wed, 27 Apr 2022 21:15:50 +0000 (UTC) Received: by mail-pf1-f171.google.com with SMTP id y14so2584936pfe.10 for ; Wed, 27 Apr 2022 14:15:54 -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=tVJB9dSMnfbdJVaf/gmB45SM5TW0LJAgggwTw5mOlBA=; b=WZrO/1fFMa5qRl0xWd5vebsGDsZBZen/3urBrsXXICF6F/CgcOCikt+FLw/n9Seyun BfZcUxUffn3Fv/qvzJ4Snv/DGyjCqea3kPka177GAl6mpwTDUyRyg1DkOJJqBBnnV0gr 8WWQ/SqpPOxfpwwSOvM1AdV2KrhA/U0SHUo4KE5XMDIudjRsjmCg6j/g+I8zoBgtJTbp c5L6Fl6Sd+SfiKdppwcVqDaIQeo/dDWd8uWRBfb6FYLXoCOkNc+Y+fgUgtNlTk92Ezz7 m9ilcPyXqZSBr0P8PC4bAlckfKXdvdEclHNp7oePKQ5makR9O2BSBK6nWnpn69vrTFmO nYOA== 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=tVJB9dSMnfbdJVaf/gmB45SM5TW0LJAgggwTw5mOlBA=; b=PXsrh2NUvcJ7TmrutJLhyTyRMe/OiPOIrDZZv2FtAq18npJMnlaz5zcwoX5z3tlatW uaTSwhzewaQDrxFtpadhEpAywXlj2n8dRT4dZwozqrRLHFjtxSAlsLSfpKsC39ls6vtf aK/0r58N4ndmuC1a3ZS+aQDF0Fir0+j4vBnQDFWn1WMf61//T6Y/p9goTqxgH43pyhTm OrMMh85fEci0gdlrNrTteYGqqjrjil0OQdyFY8uqt5z2bFkT7pnfn+FVXwDktPMiKlOL 1aufq5h+pC1yQwDfuu3EW65VGwmR7FXZEAWP3seLrDmPlm7paayfxMYCaaGYRIK+c3St h5Xg== X-Gm-Message-State: AOAM533a7/QEe49S5cLKEPgndiuYSC7kVqpKxioIE6DxH0RIcoVY0vgo xF7yUKiudrW/YLBJKGtc4j9iQeeMnrZ/e4g+dnbFBS6j X-Google-Smtp-Source: ABdhPJyZyQd8xYMHdqZw/abHObvPrParb/gWqL822ve1Qd6/7oK7WAtbZijmH9n/ei6UFy+oNkBHYUzoa8H6Ez17/0w= X-Received: by 2002:a63:90ca:0:b0:3aa:fff3:6f76 with SMTP id a193-20020a6390ca000000b003aafff36f76mr19247792pge.206.1651094153931; Wed, 27 Apr 2022 14:15:53 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Yang Shi Date: Wed, 27 Apr 2022 14:15:41 -0700 Message-ID: Subject: Re: [PATCH 2/2 RESEND] mm/huge_memory: do not overkill when splitting huge_zero_page To: Xu Yu Cc: Linux MM , Andrew Morton , =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="WZrO/1fF"; spf=pass (imf04.hostedemail.com: domain of shy828301@gmail.com designates 209.85.210.171 as permitted sender) smtp.mailfrom=shy828301@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 9522240064 X-Stat-Signature: 46dekjyrb7e7t646fxzsdaxhxaw1qq1q X-HE-Tag: 1651094150-902994 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 Wed, Apr 27, 2022 at 2:45 AM Xu Yu wrote: > > Kernel panic when injecting memory_failure for the global > huge_zero_page, when CONFIG_DEBUG_VM is enabled, as follows. > > Injecting memory failure for pfn 0x109ff9 at process virtual address 0x20ff9000 > page:00000000fb053fc3 refcount:2 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x109e00 > head:00000000fb053fc3 order:9 compound_mapcount:0 compound_pincount:0 > flags: 0x17fffc000010001(locked|head|node=0|zone=2|lastcpupid=0x1ffff) > raw: 017fffc000010001 0000000000000000 dead000000000122 0000000000000000 > raw: 0000000000000000 0000000000000000 00000002ffffffff 0000000000000000 > page dumped because: VM_BUG_ON_PAGE(is_huge_zero_page(head)) > ------------[ cut here ]------------ > kernel BUG at mm/huge_memory.c:2499! > invalid opcode: 0000 [#1] PREEMPT SMP PTI > CPU: 6 PID: 553 Comm: split_bug Not tainted 5.18.0-rc1+ #11 > Hardware name: Alibaba Cloud Alibaba Cloud ECS, BIOS 3288b3c 04/01/2014 > RIP: 0010:split_huge_page_to_list+0x66a/0x880 > Code: 84 9b fb ff ff 48 8b 7c 24 08 31 f6 e8 9f 5d 2a 00 b8 b8 02 00 00 e9 e8 fb ff ff 48 c7 c6 e8 47 3c 82 4c b > RSP: 0018:ffffc90000dcbdf8 EFLAGS: 00010246 > RAX: 000000000000003c RBX: 0000000000000001 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff823e4c4f RDI: 00000000ffffffff > RBP: ffff88843fffdb40 R08: 0000000000000000 R09: 00000000fffeffff > R10: ffffc90000dcbc48 R11: ffffffff82d68448 R12: ffffea0004278000 > R13: ffffffff823c6203 R14: 0000000000109ff9 R15: ffffea000427fe40 > FS: 00007fc375a26740(0000) GS:ffff88842fd80000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fc3757c9290 CR3: 0000000102174006 CR4: 00000000003706e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > try_to_split_thp_page+0x3a/0x130 > memory_failure+0x128/0x800 > madvise_inject_error.cold+0x8b/0xa1 > __x64_sys_madvise+0x54/0x60 > do_syscall_64+0x35/0x80 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7fc3754f8bf9 > Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 8 > RSP: 002b:00007ffeda93a1d8 EFLAGS: 00000217 ORIG_RAX: 000000000000001c > RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc3754f8bf9 > RDX: 0000000000000064 RSI: 0000000000003000 RDI: 0000000020ff9000 > RBP: 00007ffeda93a200 R08: 0000000000000000 R09: 0000000000000000 > R10: 00000000ffffffff R11: 0000000000000217 R12: 0000000000400490 > R13: 00007ffeda93a2e0 R14: 0000000000000000 R15: 0000000000000000 > > We think that raising BUG is overkilling for splitting huge_zero_page, > the huge_zero_page can't be met from normal paths other than memory > failure, but memory failure is a valid caller. So we tend to replace the > BUG to WARN + returning -EBUSY, and thus the panic above won't happen > again. Reviewed-by: Yang Shi > > Suggested-by: Yang Shi > Cc: Naoya Horiguchi > Reported-by: kernel test robot > Signed-off-by: Xu Yu > --- > mm/huge_memory.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index c468fee595ff..910a138e9859 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -2495,11 +2495,16 @@ int split_huge_page_to_list(struct page *page, struct list_head *list) > struct address_space *mapping = NULL; > int extra_pins, ret; > pgoff_t end; > + bool is_hzp; > > - VM_BUG_ON_PAGE(is_huge_zero_page(head), head); > VM_BUG_ON_PAGE(!PageLocked(head), head); > VM_BUG_ON_PAGE(!PageCompound(head), head); > > + is_hzp = is_huge_zero_page(head); > + VM_WARN_ON_ONCE_PAGE(is_hzp, head); > + if (is_hzp) > + return -EBUSY; > + > if (PageWriteback(head)) > return -EBUSY; > > -- > 2.20.1.2432.ga663e714 >