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 83EB6D17120 for ; Mon, 21 Oct 2024 17:57:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC8DD6B0082; Mon, 21 Oct 2024 13:57:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E78BC6B0083; Mon, 21 Oct 2024 13:57:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D672E6B0085; Mon, 21 Oct 2024 13:57:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id B99B06B0082 for ; Mon, 21 Oct 2024 13:57:46 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 07C20A1B56 for ; Mon, 21 Oct 2024 17:57:18 +0000 (UTC) X-FDA: 82698366912.12.E68DEE6 Received: from out-185.mta1.migadu.com (out-185.mta1.migadu.com [95.215.58.185]) by imf04.hostedemail.com (Postfix) with ESMTP id 3208340013 for ; Mon, 21 Oct 2024 17:57:24 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=xU0NQeuF; spf=pass (imf04.hostedemail.com: domain of shakeel.butt@linux.dev designates 95.215.58.185 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1729533315; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NgUgtE2nbHu0jbUYd7lK1pAQWkPQaUgbx1VksnZptik=; b=Rf0DllzOqfcgFEuc1TCaXymnhxt3QOr2mzvDIeQGqO+kmfVzEkGSX4+tQfl9UkKGgXkzjg Lig8Sa7GfE5lqdjsv13CMwn6iKS2Zf2kiIsvArvjS5NkYbiy0zL/1kN84Reqwti+MnSMTy IzLOcM3Kk7b3LbJqL9v+Fw0a89sJPok= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1729533315; a=rsa-sha256; cv=none; b=JuDGVG5SNQI9Q8TlxOA/VZgBgfxuiNVyES2hU6xGexZdAs0N4r8S6rxZ3rC+U/5LBs7sk7 OmhnKFzZTPy7YhUoIN300O36h2jxcnJKNZZS0KJvrmAziFPhAwdmMq4bLd7463i5tnGQkK oD2U6ncLO1RwODqbH122Bw82zj0vvkI= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=xU0NQeuF; spf=pass (imf04.hostedemail.com: domain of shakeel.butt@linux.dev designates 95.215.58.185 as permitted sender) smtp.mailfrom=shakeel.butt@linux.dev; dmarc=pass (policy=none) header.from=linux.dev Date: Mon, 21 Oct 2024 10:57:35 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1729533462; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=NgUgtE2nbHu0jbUYd7lK1pAQWkPQaUgbx1VksnZptik=; b=xU0NQeuF+r822oYJuRq2qZer4XWftar82dt65Iq58ThWtQpkf+k8hJBA9zqEIrF3VRLz+L aL4tTXRZfxP6YnsfFljN/fmYmls5KErKxV6YDOYJnnJhj9Z2zEegcuWNE3RT2KR/LI+D9I 0Xr/KKFF3MiaQKTf8XLDgauGkjGYjOQ= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Shakeel Butt To: Roman Gushchin Cc: Andrew Morton , linux-mm@kvack.org, Vlastimil Babka , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Hugh Dickins , Matthew Wilcox Subject: Re: [PATCH v2] mm: page_alloc: move mlocked flag clearance into free_pages_prepare() Message-ID: References: <20241021173455.2691973-1-roman.gushchin@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241021173455.2691973-1-roman.gushchin@linux.dev> X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 3208340013 X-Stat-Signature: mdhk7ds4objeeczkmi8mgh34nxmyrbwa X-Rspamd-Server: rspam09 X-Rspam-User: X-HE-Tag: 1729533444-882956 X-HE-Meta: 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 WpExdTSb hLPc+kFeYY0LS0AAtgo3hsCn12Zgs94qJXG1WzlBlbEPwBTcxhHBEOsmiukgAbnrqdtNjclZq0OM95pvBsIThd5HmLLYAQaH4XHktvnfes8doUgOeR0BHrg4J0+Z4vKfY5r4essTP/dMC9YgB3wHziOdnNASZo7BLY61W1mPerigPbmmmqqbW6LKxz5g93LBu75nJj/idR73nGOwA5KNKR0Fk+HIoFZR+mKLrjNMWNArQwsp6Ooprm5dMRA== 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: List-Subscribe: List-Unsubscribe: On Mon, Oct 21, 2024 at 05:34:55PM GMT, Roman Gushchin wrote: > Syzbot reported a bad page state problem caused by a page > being freed using free_page() still having a mlocked flag at > free_pages_prepare() stage: > > BUG: Bad page state in process syz.0.15 pfn:1137bb > page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8881137bb870 pfn:0x1137bb > flags: 0x400000000080000(mlocked|node=0|zone=1) > raw: 0400000000080000 0000000000000000 dead000000000122 0000000000000000 > raw: ffff8881137bb870 0000000000000000 00000000ffffffff 0000000000000000 > page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set > page_owner tracks the page as allocated > page last allocated via order 0, migratetype Unmovable, gfp_mask > 0x400dc0(GFP_KERNEL_ACCOUNT|__GFP_ZERO), pid 3005, tgid > 3004 (syz.0.15), ts 61546 608067, free_ts 61390082085 > set_page_owner include/linux/page_owner.h:32 [inline] > post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1537 > prep_new_page mm/page_alloc.c:1545 [inline] > get_page_from_freelist+0x3008/0x31f0 mm/page_alloc.c:3457 > __alloc_pages_noprof+0x292/0x7b0 mm/page_alloc.c:4733 > alloc_pages_mpol_noprof+0x3e8/0x630 mm/mempolicy.c:2265 > kvm_coalesced_mmio_init+0x1f/0xf0 virt/kvm/coalesced_mmio.c:99 > kvm_create_vm virt/kvm/kvm_main.c:1235 [inline] > kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5500 [inline] > kvm_dev_ioctl+0x13bb/0x2320 virt/kvm/kvm_main.c:5542 > vfs_ioctl fs/ioctl.c:51 [inline] > __do_sys_ioctl fs/ioctl.c:907 [inline] > __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0x69/0x110 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > page last free pid 951 tgid 951 stack trace: > reset_page_owner include/linux/page_owner.h:25 [inline] > free_pages_prepare mm/page_alloc.c:1108 [inline] > free_unref_page+0xcb1/0xf00 mm/page_alloc.c:2638 > vfree+0x181/0x2e0 mm/vmalloc.c:3361 > delayed_vfree_work+0x56/0x80 mm/vmalloc.c:3282 > process_one_work kernel/workqueue.c:3229 [inline] > process_scheduled_works+0xa5c/0x17a0 kernel/workqueue.c:3310 > worker_thread+0xa2b/0xf70 kernel/workqueue.c:3391 > kthread+0x2df/0x370 kernel/kthread.c:389 > ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147 > ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 > > A reproducer is available here: > https://syzkaller.appspot.com/x/repro.c?x=1437939f980000 > > The problem was originally introduced by > commit b109b87050df ("mm/munlock: replace clear_page_mlock() by final > clearance"): it was handling focused on handling pagecache > and anonymous memory and wasn't suitable for lower level > get_page()/free_page() API's used for example by KVM, as with > this reproducer. > > Fix it by moving the mlocked flag clearance down to > free_page_prepare(). > > The bug itself if fairly old and harmless (aside from generating these > warnings). > > Closes: https://syzkaller.appspot.com/x/report.txt?x=169a47d0580000 Can you open the access to the syzbot report?