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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 54DD0F4BB82 for ; Tue, 24 Feb 2026 20:55:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 39F836B0005; Tue, 24 Feb 2026 15:55:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 34D426B0089; Tue, 24 Feb 2026 15:55:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 24F1F6B008A; Tue, 24 Feb 2026 15:55:45 -0500 (EST) 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 136C76B0005 for ; Tue, 24 Feb 2026 15:55:45 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id AD13C14032D for ; Tue, 24 Feb 2026 20:55:44 +0000 (UTC) X-FDA: 84480556608.26.E401FE5 Received: from omta040.useast.a.cloudfilter.net (omta040.useast.a.cloudfilter.net [44.202.169.39]) by imf15.hostedemail.com (Postfix) with ESMTP id C2E89A0007 for ; Tue, 24 Feb 2026 20:55:41 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=w6rz.net header.s=default header.b=y5Zgh8rs; spf=pass (imf15.hostedemail.com: domain of re@w6rz.net designates 44.202.169.39 as permitted sender) smtp.mailfrom=re@w6rz.net; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1771966542; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=605D1atgrhxBK+g/fa4UaJI857HWMWFLmIjAiil6I1I=; b=6zXcjZUK9SEJgXgSirIXoIync2hDiwaK7xUAEeQV1T60POraOl3drkdMhWX+9eNg8kRNFf 77Wo8cAQQDEvZCHlfhjTjRJknjxejSXd2qlgkIjd9e8zoS0bHbpC+oKsmoZMj0fOS+BgYU nmmNPA19OmaiZXIDCjpd4ULw1FQE0eI= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1771966542; a=rsa-sha256; cv=none; b=1KTneJ2+00MZ4AAkWaakIEMNnPf6i3KnZ1FU5tscCjGawPzUfY75+dAVp2ZML8Eb0CuMkE 6lQa1TD8TEssz3A0DMbaBcSM94ankTqCTjvtityL0HJ7jigC4IDeYVuztRCMZEXphrOwHl 2Uh4F0FpuUOOnnHN6jCAlUOM7wuIXkk= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=w6rz.net header.s=default header.b=y5Zgh8rs; spf=pass (imf15.hostedemail.com: domain of re@w6rz.net designates 44.202.169.39 as permitted sender) smtp.mailfrom=re@w6rz.net; dmarc=none Received: from eig-obgw-6001b.ext.cloudfilter.net ([10.0.30.143]) by cmsmtp with ESMTPS id umOqv9IUkCxrGuzRUvXitA; Tue, 24 Feb 2026 20:55:41 +0000 Received: from box5620.bluehost.com ([162.241.219.59]) by cmsmtp with ESMTPS id uzRUvqbJ9cu11uzRUv4HgT; Tue, 24 Feb 2026 20:55:40 +0000 X-Authority-Analysis: v=2.4 cv=bKYWIO+Z c=1 sm=1 tr=0 ts=699e104c a=30941lsx5skRcbJ0JMGu9A==:117 a=30941lsx5skRcbJ0JMGu9A==:17 a=IkcTkHD0fZMA:10 a=HzLeVaNsDn8A:10 a=7vwVE5O1G3EA:10 a=VwQbUJbxAAAA:8 a=HaFmDPmJAAAA:8 a=7jLG3vr0xv3RlmufI5wA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=nmWuMzfKamIsx3l42hEX:22 a=L5EjiQpGQaFGZdqT14z7:22 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=w6rz.net; s=default; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=605D1atgrhxBK+g/fa4UaJI857HWMWFLmIjAiil6I1I=; b=y5Zgh8rsy0gArKveqbuKhkEZIt Z6a5DQ/DxsNIuzv0rP5sjhacVvbGEJaHaR6/s309cUj+lcdWRZH/t36PhAmJ7zEaMV1eVeDhMDyV+ pi54uIw3TlVLgHQIJTQBlKMM7yE0Gs1jFhnAgKccaQnf+gutAa5ij9XfqQ7fUOXAc8kUtukTY14Kv uwgQcLJI9jED4zf5V7y2oo8ex0EOIYwQY2WZrjHTh+iXBSmyt6HTZwI6F7lcM5KTkBdZKMeFvdJap a07VBh9hbByd/2tAGkvy1hiMvY1/9502XXOjzU4Q/PfmgwRAwmsACU/e/aJEfv/xmV+5+xGojimje vMfZLk1g==; Received: from c-73-162-206-103.hsd1.ca.comcast.net ([73.162.206.103]:52214 helo=[10.0.1.180]) by box5620.bluehost.com with esmtpsa (TLS1.3) tls TLS_AES_128_GCM_SHA256 (Exim 4.98.2) (envelope-from ) id 1vuzRT-00000000bqv-39S0; Tue, 24 Feb 2026 13:55:39 -0700 Message-ID: <5a08d5c5-a91b-458b-8434-84566387a27e@w6rz.net> Date: Tue, 24 Feb 2026 12:55:37 -0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: mm: Regression with v7.0-rc1 on RISC-V To: Zi Yan , "David Hildenbrand (Arm)" Cc: wangkefeng.wang@huawei.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, jackmanb@google.com, jane.chu@oracle.com, hannes@cmpxchg.org, willy@infradead.org, muchun.song@linux.dev, osalvador@suse.de, sidhartha.kumar@oracle.com, vbabka@suse.cz, claudiu.beznea.uj@bp.renesas.com, Mark Brown , akpm@linux-foundation.org, pjw@kernel.org References: <1b17c38f-30d3-4bb4-a7e1-e74b19ada885@w6rz.net> <13b8d60d-1209-4650-9fa5-982381c53512@kernel.org> <1966378802.577797.1771952827516@app.mailbox.org> <78D36EC1-2596-448A-A939-0A1AC7B3D1BC@nvidia.com> <1AB3E96B-F4CA-4B00-9078-2AC20A1A60DC@nvidia.com> <272A58BA-445F-46F9-8DAB-D82E43D7771A@nvidia.com> Content-Language: en-US From: Ron Economos In-Reply-To: <272A58BA-445F-46F9-8DAB-D82E43D7771A@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box5620.bluehost.com X-AntiAbuse: Original Domain - kvack.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - w6rz.net X-BWhitelist: no X-Source-IP: 73.162.206.103 X-Source-L: No X-Exim-ID: 1vuzRT-00000000bqv-39S0 X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: c-73-162-206-103.hsd1.ca.comcast.net ([10.0.1.180]) [73.162.206.103]:52214 X-Source-Auth: re@w6rz.net X-Email-Count: 15 X-Org: HG=bhshared;ORG=bluehost; X-Source-Cap: d3NpeHJ6bmU7d3NpeHJ6bmU7Ym94NTYyMC5ibHVlaG9zdC5jb20= X-Local-Domain: yes X-CMAE-Envelope: MS4xfKne/hb8BLrlt8xG3/WT4TjfNF0urRAFKnDxtJVU7zye3ucZm3O6MCUNBMabcIDWUuQLcsinUbhFPoMp7aunAiNLIwSzYLeNe8M94n7Zmv59Dv0b11Zl JeY/EO66AOJ5nu7o7JOeX1627EnLDx1MpOBJPeg7MX0F5C8juUeZtRVxYROABFDifync+vP+L0JNaA== X-Rspamd-Server: rspam09 X-Stat-Signature: 9hg8u19zxp38u4js188zauonkjzwzx9m X-Rspamd-Queue-Id: C2E89A0007 X-Rspam-User: X-HE-Tag: 1771966541-852445 X-HE-Meta: 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 mSseoOEi 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/24/26 09:29, Zi Yan wrote: > On 24 Feb 2026, at 12:17, Zi Yan wrote: > >> On 24 Feb 2026, at 12:14, Zi Yan wrote: >> >>> On 24 Feb 2026, at 12:07, David Hildenbrand wrote: >>> >>>>> David Hildenbrand (Arm) hat am 24.02.2026 12:00 CET geschrieben: >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> On 2/24/26 09:37, Ron Economos wrote: >>>>> >>>>>> I'm getting a BUG dump during shutdown with Linux v7.0-rc1 on RISC-V. >>>>>> >>>>>> >>>>>> >>>>>> [ OK ] Reached target shutdown.target - System Shutdown. >>>>>> >>>>>> [ OK ] Reached target final.target - Late Shutdown Services. >>>>>> >>>>>> [ OK ] Finished systemd-reboot.service - System Reboot. >>>>>> >>>>>> [ OK ] Reached target reboot.target - System Reboot. >>>>>> >>>>>> [ 173.985249] BUG: Bad page state in process shutdown pfn:f8850 >>>>>> >>>>>> [ 173.985311] page: refcount:1 mapcount:0 mapping:0000000000000000 >>>>>> >>>>>> index:0x0 pfn:0xf8850 >>>>>> >>>>>> [ 173.985336] flags: 0xffff80000000000(node=0|zone=0| >>>>>> >>>>>> lastcpupid=0x1ffff) CMA >>>>>> >>>>>> [ 173.985365] raw: 0ffff80000000000 ffffffc501e21448 ffffffc600f2ae88 >>>>>> >>>>>> 0000000000000000 >>>>>> >>>>>> [ 173.985386] raw: 0000000000000000 0000000000000000 00000001ffffffff >>>>>> >>>>>> 0000000000000000 >>>>>> >>>>>> [ 173.985403] page dumped because: nonzero _refcount >>>>> So, we're freeing something from CMA in cma_release(). >>>>> >>>>> >>>>> >>>>> In cma_release() we iterate all pages to decrement their refcount >>>>> >>>>> >>>>> >>>>> VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn))); >>>>> >>>>> >>>>> >>>>> I would expect that this would fire already if there is still a page >>>>> >>>>> referenced. >>>>> >>>>> >>>>> >>>>> Are you running with CONFIG_DEBUG_VM=y ? >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> -- >>>>> >>>>> Cheers, >>>>> >>>>> >>>>> >>>>> David >>>> Thinking again without my computer at hand … isn‘t the call completely optimized out without CONFIG_DEBUG_VM? >>>> >>>> >>>> >>>> At least that’s what I remember. >>> Right. Without CONFIG_DEBUG_VM=y, VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn))) >>> and is_check_pages_enabled(), which leads to free_page_is_bad()’s >>> “page dumped because: nonzero _refcount”, are disabled. >>> >>> It seems to me that someone else bump the page refcount between >>> VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn))) and free_page_is_bad(). >>> >> Merging Ron’s reply from another thread[1]: >> >> “Something strange is going on. I enabled CONFIG_DEBUG_VM by itself and >> the issue went away. Let me try CONFIG_DEBUG_PAGE_REF.” >> >> Looks like something is racy, since it is reproducible reliably. >> >> [1] https://lore.kernel.org/all/30dd1efc-9bd9-4664-999e-610d181600f9@w6rz.net/ > VM_WARN_ON() is BUILD_BUG_ON_INVALID() when CONFIG_DEBUG_VM is off. Only > the validity of the expression is checked and no code is generated. > So that put_page_testzero() becomes a NOP. > > Hi Ron, > > Can you check if the patch below fix the issue without CONFIG_DEBUG_VM? > > diff --git a/mm/cma.c b/mm/cma.c > index 94b5da468a7d..96be62eb3713 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -1020,8 +1020,11 @@ bool cma_release(struct cma *cma, const struct page *pages, > return false; > > pfn = page_to_pfn(pages); > - for (i = 0; i < count; i++, pfn++) > - VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn))); > + for (i = 0; i < count; i++, pfn++) { > + int __maybe_unused ret = put_page_testzero(pfn_to_page(pfn)); > + > + VM_WARN_ON(!ret); > + } > > __cma_release_frozen(cma, cmr, pages, count); > > > > Best Regards, > Yan, Zi Yes, that patch fixes the issue.