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 EB1C860A262D for ; Thu, 29 Oct 2026 20:45:00 +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=GauLCy/1 Received: by kanga.kvack.org (Postfix) id 587F56B05D4; Thu, 29 Oct 2026 16:44:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 55EEF6B05D5; Thu, 29 Oct 2026 16:44:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 475D76B05D6; Thu, 29 Oct 2026 16:44:39 -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 119356B05D4 for ; Thu, 29 Oct 2026 16:44:39 -0400 (EDT) Received: from smtpin16.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 98048C04ED for ; Thu, 29 Oct 2026 20:44:38 +0000 (UTC) X-FDA: 85376842236.16.587438E Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id AFEF218000B for ; Thu, 29 Oct 2026 20:44:36 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="GauLCy/1"; spf=pass (imf06.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793306676; 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=OmrddnalYvKzrQnN9N4Fpu9NVAES2TsOMe4SsI3z9gU=; b=NujfvWXKDxPV4YwGmKonTDlko9H0S+xlB6a9Hn/gntY7Cisg0VWVx9Ktiln6yFr7Ichrnd zE6YYMcgeSy3Eh6dJm+DyUHIqp5nnb/RSvNILOT5NLi8ad3qPX+zElmwYE0u85Hpwk+Y2d Uwq4smTVQTQ7Sno6d3yNgcjiwCmgvVI= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793306676; b=4oCJo9lv5cCfn+aP5Fn5aTRDiRG9eg4/+nHoJzVDfNB4bsIOo8RBo01MB9EUcUYO/s1B1U gB63tjMJPCV06UlUwH3Fe1I6jvUyi4/fKIqnaDACJGXeAkq+mrg9K7dxLu1MLkYBqfhF+4 +gf8cN2AajefaPzIp/T6c4+rTAUZCso= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="GauLCy/1"; spf=pass (imf06.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id B7B8541082; Thu, 29 Oct 2026 20:44:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B00911F01825; Thu, 29 Oct 2026 20:44:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793306675; bh=OmrddnalYvKzrQnN9N4Fpu9NVAES2TsOMe4SsI3z9gU=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=GauLCy/1HrYbdieZoYJGY/PpIUS1vgONUu0M4PlXJvY7eY+GegQj06Bc3k52Nn7Cw 5pUOiZmQPSa/agrZVJmrfiWcTl/MEWxkZ9UQsk7lluRie9slFArS3/SevT9Xccdva3 jp2ZFiK7k5Rm5+WgEwWwD32w960RLwKV1pQDqkERuQqbjtkTQtpbzWr7jdja43hl2C c8k7J5I4N2CU6YXX6Fvp4i5opY3LoX3l2OPr87naVfONU+oHtwZSXt5gIoOIzHgVXo jtFFykZR1o4q1kxv0399ek+IcViDhuU9YWAlcP+xsYEpMNrWrwGCMJzm0kwU8GDd9N c2NA3KmLJdFDw== From: "David Hildenbrand (Arm)" Date: Thu, 29 Oct 2026 21:33:40 +0100 Subject: [PATCH v2 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: <20261029-fixes_core-v2-45-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> In-Reply-To: <20261029-fixes_core-v2-0-a64ce7f83abb@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=2252; i=david@kernel.org; h=from:subject:message-id; bh=3kpfFp5NOxLKJV7MN0qgqEyHjOOrTqFsf7HE3Qur7Ks=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLIer+16LPZT4EOJ2H3DwG0neWorjk3wfGRVsoy7nXl93 YOjzLF9HaUsDGIcDLJiiixBwfcNXr5cV1vtxscMM4eVCWQIAxenAEzk7zaG/wGvIi2+nrw7edI2 i513/4c0ZS6asqr28e2KUp2fNmp7rUMZfrPoSJ2ovysSvbya44cCH9+H3rqFRjUPV/WUWk7Yv/V nMCsA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: AFEF218000B X-Stat-Signature: 7duxx147x3h91xy1sybmdsf6oemmp8ni X-Rspam-User: 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=ham autolearn_force=no version=4.0.1 X-HE-Tag: 1793306676-484773 X-HE-Meta: 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 DkK5ZTfq qKgoQ+hBBZZ098vyhkXIDcpK2+4QZkMk7WSMDS5ePtJQdXGk0UpG0ymAjELUAljczEweMSu7FlOaeYQIKdNQjr2h4Fr2YoVeBtWcCdht4VluT2JkqMkzHsYHzS5c/ga7KDk1XWS3EFlgDewF3tQVXn621UGHfpQU0tK67gIAGoitwOJvuA/JI3XI5vH1gUQVVbQpAXkbl3yQiZ3A7ms6pNPVPHJpQ8KP6VZ9CaQmpL7iGw3jvR02hb86VIRFPwcPeHKfNUKtDQnZeGL+FEtMXMr0ItGdxdsJg0iY1JEGGoB5RE6B8U52yVkjVD4KuZx6e11KWL/oBJUaqCnYPVvWeDGGVQpCnkWE8OAN30Ychz4r4GGV2IRI+S0LbkReBDgDg1PpVrYlxBHjIM/zo+7SI3n/qb9A37mZL4MEnzN2smngG/SXvsx+8dGVmXec7jzIjgxFlVPi6N0XwGL1wrMQddfAheQ== 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 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 a10ea37a261d..871f95c9ae9f 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