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 A0BB1C87FC9 for ; Tue, 29 Jul 2025 14:49:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 402366B008C; Tue, 29 Jul 2025 10:49:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 3D9DA6B0093; Tue, 29 Jul 2025 10:49:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 316B56B0095; Tue, 29 Jul 2025 10:49:59 -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 1F6C96B008C for ; Tue, 29 Jul 2025 10:49:59 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id D016C1A00E9 for ; Tue, 29 Jul 2025 14:49:58 +0000 (UTC) X-FDA: 83717586876.10.88350B4 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf15.hostedemail.com (Postfix) with ESMTP id A979FA000A for ; Tue, 29 Jul 2025 14:49:55 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=f0M8jh1E; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf15.hostedemail.com: domain of gregkh@linuxfoundation.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1753800597; 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=SVKTJmQyfHUB47s4869m+0Nps+tqQ4H1sD3IUQa2NaI=; b=8FR7wiLOv7Kop4n8cdz2xYxZuLeLXrUU3s599NV3wSVocUME+YBSgHzuzf3H8VnsriT78N hyh66vK6SGt+bHw1ieXGEXhm3I4VfRypfEqo3IJX9xER2aPnj0nPyp6xIJJjQksTqdaHFe Nh7HhP2SKbY3It0/ySt7TgB5W5t5zCo= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1753800597; a=rsa-sha256; cv=none; b=Em5CUa/VQ1odVU0Su4nokJSJgE/JyH5/MtATsfDodgdHbN40gm837K/1qFmH/izQRyFBKj jHsbMNSAYxK3gN42Nrj3cUlDmm+RqGNRCOi4udrkgH2TMZAWbprIefCsRiy/pDYRnnuGcc JZiNi069OyWeXb/IsO6I/sgpKb7R3Fs= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=f0M8jh1E; dmarc=pass (policy=none) header.from=linuxfoundation.org; spf=pass (imf15.hostedemail.com: domain of gregkh@linuxfoundation.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id E343BA544D8; Tue, 29 Jul 2025 14:49:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09A41C4CEEF; Tue, 29 Jul 2025 14:49:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753800594; bh=8WHu65Du/5RAZ7vIpLgroUB1ihWHIGMcCMvNDR1D48w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f0M8jh1E567Dzc3VA74jPcIWNmhbrWXFrtgIR+481l4ITDFj3cWe2icTVpA176/Lk UxRnG1qinStkhCVNNpHX89TXWi14XyKBQKvWfXD//W1GQONi1zFZYJTGsbu+LAxBz5 sYm3dQftOPHbWiU0MEKRivX361+bsOcsDozaG1vk= Date: Tue, 29 Jul 2025 16:49:51 +0200 From: Greg KH To: Jakub Acs Cc: stable@vger.kernel.org, Liu Shixin , Yang Shi , David Hildenbrand , Chengming Zhou , Johannes Weiner , Kefeng Wang , Mattew Wilcox , Muchun Song , Nanyong Sun , Qi Zheng , Andrew Morton , linux-mm@kvack.org Subject: Re: [PATCH 6.12.y] mm: khugepaged: fix call hpage_collapse_scan_file() for anonymous vma Message-ID: <2025072932-scorer-manhood-b6fc@gregkh> References: <20250729090347.17922-1-acsjakub@amazon.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250729090347.17922-1-acsjakub@amazon.de> X-Rspamd-Queue-Id: A979FA000A X-Stat-Signature: qwfr8w738mw8ahsw4s14onhgzkf8wokn X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1753800595-948427 X-HE-Meta: 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 qakbl3jw U8dQZgeLRFJcjTjvtF1jymDOo7BTAdIpf1u236953+OvYmFO00YhAEHzuE+Rx1f9lLha+E0bjvSRH8671My86bvwrAMaMpB3fAvbeFpk3C2GVCIqs1Od9OniCvO/UmPMsTv2w/uFwdx2zS1TifIf9XtYbhSkzLfsL7Zns7gMGJqTWGGFaMMqdeawWkj+VGtJKIO6VHGyhVpNUyQzHTA+wQOuLyjQ92GkceW6kf8jYKFWXPhupODJWBr5QGM20xdEzHOk/kgXoRT8PXtZKZzIGBjiUcf3e3BgFEW4ZvYO3U2joZH13fV0RO6Ggivlar/XaeRk0Bw38ldl46w+vuJFcvVlmAIZu0tx7d2bPT8sKJkCKnbP9P1+KAkEMSrDpVWfkEox8AAryIYyGxXPbIe+ioxXymkmSmqy+ejY7NR1mgGOaV+qEcU3bqFao3SWMvZyMI1NGADbaSUZAneWMPY83o11xJgYCVuHF447/euBOLp2Lg9LP9cguJVzfsZZmxmbe4xzcaiQ7ssaUtdIsfE1fBXkq6OifhITl8IRgYFf07pv91WBjCrL4zh9b+AUlrHleejYXzrk6jZCY54lWYhEqXcCJ1QsfJzPZtICSv3VSX1Q1N1eZw6WSQPgZrj17frhNk58KFnFIwZ5JVH6AMy+30o4cIZPNg/uDgJ2mVYQyuUPc7qhbKkxQkE0jjknGcn7I+yTE 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 Tue, Jul 29, 2025 at 09:03:47AM +0000, Jakub Acs wrote: > From: Liu Shixin > > commit f1897f2f08b28ae59476d8b73374b08f856973af upstream. > > syzkaller reported such a BUG_ON(): > > ------------[ cut here ]------------ > kernel BUG at mm/khugepaged.c:1835! > Internal error: Oops - BUG: 00000000f2000800 [#1] SMP > ... > CPU: 6 UID: 0 PID: 8009 Comm: syz.15.106 Kdump: loaded Tainted: G W 6.13.0-rc6 #22 > Tainted: [W]=WARN > Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 > pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) > pc : collapse_file+0xa44/0x1400 > lr : collapse_file+0x88/0x1400 > sp : ffff80008afe3a60 > ... > Call trace: > collapse_file+0xa44/0x1400 (P) > hpage_collapse_scan_file+0x278/0x400 > madvise_collapse+0x1bc/0x678 > madvise_vma_behavior+0x32c/0x448 > madvise_walk_vmas.constprop.0+0xbc/0x140 > do_madvise.part.0+0xdc/0x2c8 > __arm64_sys_madvise+0x68/0x88 > invoke_syscall+0x50/0x120 > el0_svc_common.constprop.0+0xc8/0xf0 > do_el0_svc+0x24/0x38 > el0_svc+0x34/0x128 > el0t_64_sync_handler+0xc8/0xd0 > el0t_64_sync+0x190/0x198 > > This indicates that the pgoff is unaligned. After analysis, I confirm the > vma is mapped to /dev/zero. Such a vma certainly has vm_file, but it is > set to anonymous by mmap_zero(). So even if it's mmapped by 2m-unaligned, > it can pass the check in thp_vma_allowable_order() as it is an > anonymous-mmap, but then be collapsed as a file-mmap. > > It seems the problem has existed for a long time, but actually, since we > have khugepaged_max_ptes_none check before, we will skip collapse it as it > is /dev/zero and so has no present page. But commit d8ea7cc8547c limit > the check for only khugepaged, so the BUG_ON() can be triggered by > madvise_collapse(). > > Add vma_is_anonymous() check to make such vma be processed by > hpage_collapse_scan_pmd(). > > Link: https://lkml.kernel.org/r/20250111034511.2223353-1-liushixin2@huawei.com > Fixes: d8ea7cc8547c ("mm/khugepaged: add flag to predicate khugepaged-only behavior") > Signed-off-by: Liu Shixin > Reviewed-by: Yang Shi > Acked-by: David Hildenbrand > Cc: Chengming Zhou > Cc: Johannes Weiner > Cc: Kefeng Wang > Cc: Mattew Wilcox > Cc: Muchun Song > Cc: Nanyong Sun > Cc: Qi Zheng > Signed-off-by: Andrew Morton > [acsjakub: backport, clean apply] > Cc: Jakub Acs You need to sign off on patches you forward on. Please fix that up and resend all of these. thanks, greg -h