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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, Josef Bacik , stable@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2194; i=david@kernel.org; h=from:subject:message-id; bh=yohgL4i9AjCKZukx2CMHvMiMRro+7y2Mtk1tuDA6CqQ=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLu359uMWti+vt6tyzNqsIFL978VPj9+m3+/xAF/UNbF O1m/efm6ShlYRDjYJAVU2QJCr5v8PLlutpqNz5mmDmsTCBDGLg4BWAi3wIYfjKeuiChaXFpBi9L y88Ne++/nanp0+U/z/bhwwsuQVlWqpIMf6VXeGYpJt/pz/YO87x+1KhG2j3HwqvfzPD9RNXVTlL SjAA= X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 2DC67140006 X-Stat-Signature: n9h7h6i43zkifuxkgu5etzt4nw75rsss 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: 1793057332-451290 X-HE-Meta: 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 WdXRbRfh Sj+ZEzwpNzMtna3p/HQX8CDyqdCKAb+lrBqIA9xOiDwjuNj5iiFlB5zR8VgAzzbS/DkCNF1q7Fuyslz7baLGHlPT6+iU3hxtmIE0rHgjl1I7dZsYLDst0T+NnSSnNIwHVmKZv+QrxRLDdFN4XdcBX4ivm3TeSCwq9UJL509jyrx1lHCTUfl+5fAbuB6ihTlZQcUqyOYloUhKtWEIW4xoYizbHH+X39UjPU54XO0LcthwaqYHKw6cdTl8kGaXy46HzhuNysv/Gp2J9FKKcJlXS3MlMSgrEfdb73hnN2Y3zW7cVuIk8uWz74zO41hBRMYbg8YqPkBxPvs/Ry+srgEDs3nwdQdVzdQ4ue1jfX2XSsHg6s/40va8UivklK4iHXNR28pcpqZ0ddeAJxKqbJQQWr+YKMmDT/27bcRlrZrQViyVq8Ww= 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: Josef Bacik Commit 9eab0421fa94 ("mm: fix unmap_mapping_range high bits shift bug") made holebegin and holelen unsigned before they are shifted, by casting them to pgoff_t. That is an unsigned long: on a 32-bit kernel the cast cuts off the upper half of the two loff_t values, so a hole which begins at 4 GiB or beyond is taken for one in the first 4 GiB of the file. truncate_pagecache() passes the new size of the file and asks for private COWed pages to be unmapped as well. If a file of 6 GiB is truncated to 5 GiB, everything from 1 GiB on is unmapped, and what a process has written to a private mapping of the range between 1 GiB and 5 GiB is lost: it reads the contents of the file again. Where the range has an end, the wrong range is unmapped instead of the right one. The page cache copes with that, as it unmaps every folio that it removes. The callers which only have unmap_mapping_range() to get rid of user mappings do not, for example drm_vma_node_unmap(), whose fake offsets reach beyond 4 GiB on 32-bit, and revoke_iomem() with physical addresses of more than 32 bits. Cast to u64 instead. Nothing changes for 64-bit kernels. Fix generated by an LLM and sent by Josef Bacik in private. Fixes: 9eab0421fa94 ("mm: fix unmap_mapping_range high bits shift bug") Cc: stable@vger.kernel.org Signed-off-by: Josef Bacik Acked-by: Lorenzo Stoakes (ARM) Signed-off-by: David Hildenbrand (Arm) --- mm/memory.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index ec7a1397ab833..5c5f326b8bcbe 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4649,8 +4649,8 @@ EXPORT_SYMBOL_GPL(unmap_mapping_pages); void unmap_mapping_range(struct address_space *mapping, loff_t const holebegin, loff_t const holelen, int even_cows) { - pgoff_t hba = (pgoff_t)(holebegin) >> PAGE_SHIFT; - pgoff_t hlen = ((pgoff_t)(holelen) + PAGE_SIZE - 1) >> PAGE_SHIFT; + pgoff_t hba = (u64)holebegin >> PAGE_SHIFT; + pgoff_t hlen = ((u64)holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; /* Check for overflow. */ if (sizeof(holelen) > sizeof(hlen)) { -- 2.43.0