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 925B5606A32A for ; Mon, 26 Oct 2026 23:31:48 +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=Ox2i2FSH Received: by kanga.kvack.org (Postfix) id A080D6B05CD; Mon, 26 Oct 2026 19:31:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9DF936B0600; Mon, 26 Oct 2026 19:31:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8F7666B0601; Mon, 26 Oct 2026 19:31:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 5EB506B05CD for ; Mon, 26 Oct 2026 19:31:47 -0400 (EDT) Received: from smtpin12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id CFEA3C0890 for ; Mon, 26 Oct 2026 23:31:46 +0000 (UTC) X-FDA: 85366377012.12.19BE753 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id 0C954180003 for ; Mon, 26 Oct 2026 23:31:44 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Ox2i2FSH; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.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=1793057505; 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=JOZA/d3RnlEXnMB1S+vtRBXnoN845YtQMJ+bQJINkeg=; b=6VuS7C+WEl7mFBizNkCVhgs7L9pfcdRNu96Tps/PrBguCfckb8oq8B4Wnu3oU+DqNzjCl9 oliHOIwgqonphvELkvJ/JL5fxCBDU8XsQgYgUkciqHddr7b7888ywPfe0WS42iOEbpj/NX q/DkUMPvkx9iKdQPrUi8q4EwGBoN2Cg= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Ox2i2FSH; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.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=1793057505; b=edex3bODKpjhwk0VhK8XIVcXKojtkc7T79ioE7i0wHdn+ah2VeLtbW9ReJr6sXsJMpARhw chNtzpgxlgjX265gEm87ZdxrLwYam56oLdu1ZFMjKtdnQoBXGA56X8vKkZ1drrW6Mv39dK KoIxHvi+LP6JfgZ6PjE8pGaBtJld3mY= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 56EF940953; Mon, 26 Oct 2026 23:31:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8A76E1F01825; Mon, 26 Oct 2026 23:31:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793057504; bh=JOZA/d3RnlEXnMB1S+vtRBXnoN845YtQMJ+bQJINkeg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Ox2i2FSHOypqrcZwgXnwxa5pmucASOgMRL5vDYqMTASHl2rf75YW3wQoVrkuPIuIi qWBaawkuI8mbHfObP4rg08odrulxxwWOwc2kIfSbm6V7kYxzS7kix5XDxbFQgiI57R vd/KGBmW9fqjr2ojLTHGLQyXB6fpiqHp4DCbdpXJvJtGtlMg8tu48HAXtQUxYfibsT JsLarU2SHDjaAj8xnSGSrXvbdAGQU1FoX1lIooc+b6p0m+NHqmvpSisMO7dcd3rVVw AUARD/nIWCCPO2WzwdlkLwUwJeQDZtBN2zbbbs27Pi0cCpSRpugWYDmuEeJDHrz0qE 2Nr+Rh3Vvxf7Q== From: "David Hildenbrand (Arm)" Date: Tue, 27 Oct 2026 00:18:04 +0100 Subject: [PATCH 44/46] 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: <20261027-fixes_core-v1-44-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> In-Reply-To: <20261027-fixes_core-v1-0-6f74bec9a5bb@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, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2157; i=david@kernel.org; h=from:subject:message-id; bh=nx05kHs+vYnlpcYo2GO368aldzvpDGoDSteIsZANA+4=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLu359h9zUpMrRK7P9OThHTp6//rRVNZj6uMbl9Wn3v9 c5EY4H9HaUsDGIcDLJiiixBwfcNXr5cV1vtxscMM4eVCWQIAxenAEzk7RKG/1EXTeqmP/GzifCZ ePbvbCfeC7W/VWUvTCi5K3vki/Mam/cM/ytneLn+m+4vm8X6VsRtVrGe72WWIDPnlSqnFA5NmLY kmAMA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 0C954180003 X-Stat-Signature: xe8qf14ci5ojunapw79u79mx8xegpqaf X-Spam-Status: No, score=-19.1 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: 1793057504-625242 X-HE-Meta: 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 eXk/EshS 1FGkv+MKHmVz6cK2lYY2XO1nX1i6yU6ZtC92U+w0K97+x4nuvndMFAXesiObe+jRkvcqvYf6mkWOd2JYjQjFp3WpEDxOtolB7LxZG2Y0ORV3JcFEUC1YVhU9YxoJkon78qzMYk/Mf8TDwzfCXYiaeOsniQjGwVW9GoRnl2Twhro9sgN22rNJt3VNLsg78hGJypfyvUD98k2uJWJVPS2xapV5Zj5fxR1AtntuqPe9A+B0NaIaTcUk3PIo5ROO+o389yVqr31YdylNOuXyVlUXL2HppGKSRNpVlczsOl1wRcweGj69rlz41HIEU9e1919ECtxNMJnmtkG8bpc74+QiDm3K2JXJT/fAXQpMnhqH9cmFhwJIPEAx/ccPZXuma5CW0IJ7Ayhql8psZS8AKvnlVmx0cBs/va8Ia4i8W1ruimHDzqpcPxo5bMwQFDYK5ZhyM2Xxf/4my95q36Eni3Ohk2ckCuQ== 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() ] 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