From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793439833; b=1LaGqzFcIZJybdQdXMP448ObCLAVK4x0/vSDDgK3JWN6dASYTAt35iGAIkDyNEAPfNJl ECJUUZqrFgBBZT4NWbQnaRx3Lj7us3o0lkWp8mg/9e0Yr798IU0YxBReVYcfYvTYuaLwP 6JneFgtr21fHFMNdLLJKBBtTs5vB2cAKiOcloazdIQ/EPsWfDBRovk9CdLMSLFPmfQRaV R4Tdrw7sOTL7bo3ofYCcUOnvK+NcYcRqkb3MCAVKRlkFSz5qTRHsv3rn7GcaKnk1jCFPy heeQIAnGixoHcF+vgjUhPu9+KAJhqA3OrI21u1grMDAS+w5qSKfajeFKQAuEm4smPbw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793439833; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=2OTaWQfXrVSggRAzexmllu+qraQW9cW0GF8zz7uZPRg=; b=LF21dh97Cs6wO0Y6qHse/4MGvPSdp5Tcq3FuWgnLMrq9XDBayqzqx+HO7WGuJtP4IUCq U0sZDneATG1IxtrBgpjYmvazFvcHqyqtD55hLtlwhjSxC6L6AUM/t7ie0eWwCYWahgg9M ehuZJ1Q2vq48OsIJbGS+5GgDxniw3Tlz3VWqLQ/ueUsi2+Lls0Is2c3Dp3cN4FEL/DnKP NvJPUuarDrWjfPNoezpMGGw42j4gbabINc0FCChQ3CkaM7NwsI4vFf3T2SrnEgP2zRFZL TwabwKyxcbPbVafU4cg6BZUv2Cys6qX7uWbqXFQzHuL+WQrAjF63dgmU6BXNcn3KyQA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="KH4pI/do"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9504E606A320; Sat, 31 Oct 2026 09:43:53 +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=KH4pI/do Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7E9571F000C1; Sat, 31 Oct 2026 09:43:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793439833; bh=2OTaWQfXrVSggRAzexmllu+qraQW9cW0GF8zz7uZPRg=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=KH4pI/doX3eDNZKP9hjfWDVBcMZhAxnMdgNnK8jB2wBHIOt4GUGM9QVUdga+4djCH SFc3dVznI/InHvYr4kCKZLFFjjUrQbsxFdHYXO+EO8goAT+j8khfjWIlatlZxrGm0W IFI0MElx2Iiquzr2GTcq4gWKVPHDWHXTZSWS6hSmKUsarRBLQhUnL0dypB/1HD0T2R Dt3w/2XGVRPeOtZzVMVbMUJfmBsyJanHjWlRjcuBmP8T5R4e9rewjzLRNEoVGEeEml tFIv5hVbeCSQYTjYNfa8efr44JBygWonSKu+nx5LWhhrtfkLmE8DkLZUerOI0jNTOR yy8nZjGtdXSTQ== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:39:43 +0100 Subject: [PATCH v3 14/47] mm/huge_memory: fix zapping migration entries for device-private THPs X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-14-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, Chris Mason , stable@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1574; i=david@kernel.org; h=from:subject:message-id; bh=1U0L7v2f26iQXcRLRvM3iifHsSlAqIVV1y+RDTNyPAI=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebk/TCtvK7fRx+r1Lk869iYg97/LLXlvo8a2Y4sx0S 5a825MjO0pZGMQ4GGTFFFmCgu8bvHy5rrbajY8ZZg4rE8gQBi5OAZjIyreMDLOet6xhTDvEoTVt dTzzieu10YJv+HUSgjpE024I+4QdqGRk+PzkTOLuUx5a+9x+MCTvNtjC8fIE5+I1d266vGOviHk 3nxMA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A From: Chris Mason A PMD migration entry can refer to a device-private folio. zap_huge_pmd_folio() checks the folio type instead of the entry type, so it treats such a migration entry as a device-private entry. Installing the migration entry already removed the reverse mapping and dropped the mapping reference. Zapping it must not repeat those operations. Concurrent MADV_DONTNEED during migration back to system memory can trigger this. Check the PMD entry type using pmd_is_device_private_entry(). Fix generated by an LLM and sent by Chris Mason in private. Fixes: 368076f52ebe ("mm/huge_memory: add device-private THP support to PMD operations") Cc: stable@vger.kernel.org Signed-off-by: Chris Mason [ david: simplify description ] Reviewed-by: Gregory Price (Meta) Signed-off-by: David Hildenbrand (Arm) --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1d65c4f576f9c..0c6512b33db0e 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2493,7 +2493,7 @@ static inline void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd) static void zap_huge_pmd_folio(struct mm_struct *mm, struct vm_area_struct *vma, pmd_t pmdval, struct folio *folio, bool is_present) { - const bool is_device_private = folio_is_device_private(folio); + const bool is_device_private = pmd_is_device_private_entry(pmdval); if (folio_test_anon(folio)) { add_mm_counter(mm, MM_ANONPAGES, -HPAGE_PMD_NR); -- 2.43.0