From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 63683606A329 for ; Sat, 31 Oct 2026 09:52:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Mz4vjtNh Received: by kanga.kvack.org (Postfix) id 7AC196B05F6; Sat, 31 Oct 2026 05:52:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 783A36B05F7; Sat, 31 Oct 2026 05:52:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6750E6B05F8; Sat, 31 Oct 2026 05:52:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3A8906B05F6 for ; Sat, 31 Oct 2026 05:52:00 -0400 (EDT) Received: from smtpin12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id CB9B01C4304 for ; Sat, 31 Oct 2026 09:51:59 +0000 (UTC) X-FDA: 85382455158.12.AFD1C68 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf04.hostedemail.com (Postfix) with ESMTP id 036CB40004 for ; Sat, 31 Oct 2026 09:51:57 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Mz4vjtNh; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf04.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793440318; 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=nShE2+EwYjVmjC/lA8OKz4kDZ0zHLwWOS1pXqI0CSl4=; b=2fsThP+ILHiHeSXGlPAi84zk52PnyJD0t0Z8mTLcghRSAiKrffg/MDCpQ27bE6rFtlk8G8 EWsPZuJOS4WcvvyxhMUpxaTeP2rNlHwDSQjh1ykDyfbHCE7AgnQV33JWIcAmCH4nBGmf5b b5bBfmIc2ifPATcG6jzpu9zJ4rMovl0= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Mz4vjtNh; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf04.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793440318; b=2wbTpPlKoXB7LZO532jb/pVY02us/kENCfEoLpuCkXbeOZUsg6H/mhKrJoqQ9R97ntnuDZ 1+VVVRjp0SmQVEmWOqLef1OdFEEi+7XHATsqJTvU4AM5NwPTnV3i1prsvQ9gGpP/u5WOiS ci8nxxR1tWSbAAtK8EgZuanW17XpRf8= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 421BB4120C; Sat, 31 Oct 2026 09:51:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2DFF1F000C1; Sat, 31 Oct 2026 09:51:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793440317; bh=nShE2+EwYjVmjC/lA8OKz4kDZ0zHLwWOS1pXqI0CSl4=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Mz4vjtNhUqGbGKHRoGXr9r+sytHCDgRAxGO/amotCyXaOFqxF+1ep6MZmFH4ILyUf W0soiCoF85GTYjDhg/9mZh6VMl80OhnxsHPoL552tTLwh9HXYOi/GiwLwpAiF2B8v6 VoRkh84fbkFxfEXDlZvUG5VkZQXlGgjq3C1gM8+TqM+BVpxlZsZuu/LxsBtRUhg95t hLzMpxbrGJVxeFzQgGU10iiSU+q4upIDWG/+xOTiXd2Y8NSFyVFl0CvXr4j6iUn8Id kOl8vDpFjXBoTR1k+RutPsfUG9kpI0vTOMC1dK9G3s83qVgo0bmN2ixPWHRJcO3y/C bSgnjcBQSyl0A== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:40:14 +0100 Subject: [PATCH v3 45/47] mm/cma: don't release CMA pages still in use X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-45-d6437171ecc3@kernel.org> References: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> In-Reply-To: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> To: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Gregory Price , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Muhammad Usama Anjum , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2309; i=david@kernel.org; h=from:subject:message-id; bh=571srl9637tWygfCtNc98notNFslusDCyOEoBtogIYA=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebs+eNiHr9s7IJUETNvCvfhoemf2I7a39qzNyn8o+v ZvqujLncUcpC4MYB4OsmCJLUPB9g5cv19VWu/Exw8xhZQIZwsDFKQATMS9nZGi4eqt7tvCEDa/X PrzjlHcwpuPD07izPb1PXZduX1S4LjmM4a9s/k2VDpvdc58sUZiqG171ZIX0iqVhd7+pGJmyVm2 fuZYTAA== X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Queue-Id: 036CB40004 X-Stat-Signature: 1oggj4u6n96wnn49qpyfet9zybre3q7o X-Rspamd-Server: rspam04 X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793440317-833240 X-HE-Meta: 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 1v1muPDh 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 From: Rik van Riel When a driver calls dma_free_contiguous() before quiescing DMA, the page might still have a reference from the device. put_page_testzero() there returns false, WARN fires, but the code proceeds to free_contig_frozen_range() putting a live page onto buddy and clearing the bitmap. A subsequent allocation can hand the same PFN to a new owner while the original holder still references it. A concurrent put_page() that drops the last reference between the testzero loop and free_contig_frozen_range() can double-queue the page via page->lru, corrupting buddy lists. Avoid the corruption by not freeing a CMA region if any of the pages inside are still in use. Make it explicit in the warning that the driver allowed a leak. While at it, use page_ref_freeze() to make the semantics clearer and switch to pr_warn_ratelimited(). Fixes: 9bda131c6093 ("mm: cma: add cma_alloc_frozen{_compound}()") Cc: stable@vger.kernel.org Signed-off-by: Rik van Riel Link: https://patch.msgid.link/20260811132045.5f114772@fangorn [ david: use page_ref_freeze() + pr_warn_ratelimited() ] Acked-by: Lorenzo Stoakes (ARM) Acked-by: Muchun Song Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/cma.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/cma.c b/mm/cma.c index a10ea37a261da..871f95c9ae9f0 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -1020,7 +1020,7 @@ bool cma_release(struct cma *cma, const struct page *pages, unsigned long count) { struct cma_memrange *cmr; - unsigned long ret = 0; + unsigned long leaked = 0; unsigned long i, pfn; cmr = find_cma_memrange(cma, pages, count); @@ -1029,9 +1029,13 @@ bool cma_release(struct cma *cma, const struct page *pages, pfn = page_to_pfn(pages); for (i = 0; i < count; i++, pfn++) - ret += !put_page_testzero(pfn_to_page(pfn)); + leaked += !page_ref_freeze(pfn_to_page(pfn), 1); - WARN(ret, "%lu pages are still in use!\n", ret); + if (leaked) { + pr_warn_ratelimited("%lu pages are still in use, not freeing CMA region!\n", + leaked); + return true; + } __cma_release_frozen(cma, cmr, pages, count); -- 2.43.0