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 1C08BF5545D for ; Wed, 25 Feb 2026 05:53:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 51A396B0005; Wed, 25 Feb 2026 00:53:29 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4C8276B0088; Wed, 25 Feb 2026 00:53:29 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3F4356B008A; Wed, 25 Feb 2026 00:53:29 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 295F56B0005 for ; Wed, 25 Feb 2026 00:53:29 -0500 (EST) Received: from smtpin29.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id C057314047F for ; Wed, 25 Feb 2026 05:53:28 +0000 (UTC) X-FDA: 84481911696.29.85D5BB6 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf16.hostedemail.com (Postfix) with ESMTP id 10D4518000E for ; Wed, 25 Feb 2026 05:53:26 +0000 (UTC) Authentication-Results: imf16.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf16.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1771998807; 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; bh=Xcnse+MgG/vV7O8PnEBPcGrdSo6tLe12LSghuY2hApg=; b=i1256loIs3PO1xpOZrWu9LXqFKWgWgBlvmowWXLipbj+n1BNrwGEU3er73QsdCwnbZAo49 Hmo9UVE4/7H9dJlFFeM0yhSVF3si+Q3DH7jg8jqI4Rre0PGYGtBU/G0dT7k5Od4KYWieq3 UweLs2ePnEIyHLa3pmeN2klJuUzDXUw= ARC-Authentication-Results: i=1; imf16.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf16.hostedemail.com: domain of anshuman.khandual@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=anshuman.khandual@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1771998807; a=rsa-sha256; cv=none; b=mFd5oVf7TrJOm80e9wEaDkCU/DuPLx8j1knCFJamFj5hIN1YqeOzDeR4vIhU0w7xc3Dben fYLivZviKZ/wsOz1wIKgGe/OvJwChQfhRy3Vt1z8hWIPsHWkRjo/TK2CdKfN9DHpDbkB2U DUnhRBCgovyCyo9FYksSljILKrGIcLU= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id D7C0B165C; Tue, 24 Feb 2026 21:53:19 -0800 (PST) Received: from [10.163.172.18] (unknown [10.163.172.18]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A4F3D3F7BD; Tue, 24 Feb 2026 21:53:20 -0800 (PST) Message-ID: <72855b0c-5bf1-48dc-b4b8-a04f8ac34317@arm.com> Date: Wed, 25 Feb 2026 11:23:16 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/cma: move put_page_testzero() out of VM_WARN_ON in cma_release() To: Zi Yan , Andrew Morton Cc: David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kefeng Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, SeongJae Park , Ron Economos References: <20260225031231.2352011-1-ziy@nvidia.com> Content-Language: en-US From: Anshuman Khandual In-Reply-To: <20260225031231.2352011-1-ziy@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 10D4518000E X-Stat-Signature: xcwzka6iqd691dpxfndkf5ace6oq4jkb X-HE-Tag: 1771998806-185502 X-HE-Meta: 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 BTs5GFGJ QAhTOJ6isDLhPreb1PwuNpYucXlV2kkWVHl+91K0lbq2AIzc3AdnOgFAXzKMV2H3g5kpl2PamHTqQVRUVlfw2/ah9nhhT8mJrG2ihBBZS0BQt8urwyvp2fFtcwTBnKxgJIWYriJ5Esj80mTV64AZJC6KsbO7OzDgfGS5fUfvMExgmclOhQnWTWUuMNKdejK1EYN9uXjoe/iBe7TJuOdGMugpUyZeD254bhLhtw7QI8j5gpbbbllENG4QP9qbnFpj9NBiV8Ir5y9CBIIlm9E7adCaVzL84ajVakzfg5H5Yl74JGmTPAC4Skz+8WL7+ycpziesoHqT3Bi2V0ULzQwcPUdJuPpyiHQ97KdkDnNaECj6WJoCezNkBBF1wAw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 25/02/26 8:42 AM, Zi Yan wrote: > When CONFIG_DEBUG_VM is not set, VM_WARN_ON is a NOP. Putting any statement > with side effect inside it is incorrect. Collect all !put_page_testzero() > results and check the sum using WARN instead after the loop. It restores > the same check in free_contig_range() before commit > e0c1326779cc ("mm: page_alloc: add alloc_contig_frozen_{range,pages}()"), > the commit prior to the Fixes one. > > Fixes: 9bda131c6093 ("mm: cma: add cma_alloc_frozen{_compound}()") > Reported-by: Ron Economos > Closes: https://lore.kernel.org/all/1b17c38f-30d3-4bb4-a7e1-e74b19ada885@w6rz.net/ > Suggested-by: Kefeng Wang > Signed-off-by: Zi Yan > --- > From V2: > - Collect !put_page_testzero() to get the right result. > > From V1: > - Collect all put_page_testzero() results and do a single WARN after the > loop. > > mm/cma.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/cma.c b/mm/cma.c > index 94b5da468a7d..15cc0ae76c8e 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -1013,6 +1013,7 @@ bool cma_release(struct cma *cma, const struct page *pages, > unsigned long count) > { > struct cma_memrange *cmr; > + unsigned long ret = 0; > unsigned long i, pfn; > > cmr = find_cma_memrange(cma, pages, count); > @@ -1021,7 +1022,9 @@ bool cma_release(struct cma *cma, const struct page *pages, > > pfn = page_to_pfn(pages); > for (i = 0; i < count; i++, pfn++) > - VM_WARN_ON(!put_page_testzero(pfn_to_page(pfn))); > + ret += !put_page_testzero(pfn_to_page(pfn)); > + > + WARN(ret, "%lu pages are still in use!\n", ret); > > __cma_release_frozen(cma, cmr, pages, count); > Makes sense to make the above warning unconditional regardless of CONFIG_DEBUG_VM. Reviewed-by: Anshuman Khandual