From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8AB512B94; Thu, 15 Oct 2026 22:58:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792105101; cv=none; b=oRG42u2BglZUuxC1Fex6M3a8JZ7hWxNFQoDGMi0OmhejRtmILv9PxsoQyLcmRwK94a8eEdlfo9as6xc/wMk9uEnU0169Lp+CJ6IPVV8aV4P3vK8I+z1nwNBpXDle72+yDe2M0yqxgz8rJRahEKGcjULo8YEnlogR+ClftxpTPxQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792105101; c=relaxed/simple; bh=MdWDHgnFwRQhUR/c2ERsgAqx9qXoa/diigwjMKn9iCo=; h=Date:To:From:Subject:Message-Id; b=HA3UK+PcfooCe872P39heAnJap1TRE1Auk1mwD+dfMoi70KtQ1N1vye/ekPzk6yir2+argZ4Ynliddpz+bxvVcCxNxNKeBldBYYzMPMaCBVKjHA4MUuxPJguXAa9GHEi+R7cluMgFPCeUiX2sHHBsUryyRHjubQ5xwByiYSUVVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=QbWIhkDm; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="QbWIhkDm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 345701F000C4; Thu, 15 Oct 2026 22:58:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1792105100; bh=9zDsEilw2IExJGDrBfzncpAIgcNkqqLMtTUyydtfZw0=; h=Date:To:From:Subject; b=QbWIhkDmsYRXzeWI7B/r69PKYos8O3WziI8jKMTLvkb3AKqpRqZjZO7Ej+eFAfWyA cf0TytfCCmn6IlnKD3bapPVc+8LwwREc4oX6ADc12nDCUNxsmMAycELyLT9nuVU5aH zRDbrSMiIrZb0ClMibVRHh7/qqHVzhJ5ce1IPZmI= Date: Thu, 15 Oct 2026 15:58:19 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,stable@vger.kernel.org,rppt@kernel.org,riel@surriel.com,pfalcato@suse.de,peterx@redhat.com,osalvador@suse.de,nao.horiguchi@gmail.com,muchun.song@linux.dev,mel@csn.ul.ie,ljs@kernel.org,linmiaohe@huawei.com,liam@infradead.org,kas@kernel.org,josef@toxicpanda.com,jannh@google.com,agl@us.ibm.com,david@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-hugetlb-fix-use-after-free-in-hugetlb_mfill_atomic_pte.patch added to mm-hotfixes-unstable branch Message-Id: <20261015225820.345701F000C4@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/hugetlb: fix use-after-free in hugetlb_mfill_atomic_pte() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-hugetlb-fix-use-after-free-in-hugetlb_mfill_atomic_pte.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-fix-use-after-free-in-hugetlb_mfill_atomic_pte.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "David Hildenbrand (Arm)" Subject: mm/hugetlb: fix use-after-free in hugetlb_mfill_atomic_pte() Date: Thu, 15 Oct 2026 18:07:09 +0200 Let's fix another instance where we use a folio after dropping the PTL, where someone else could e.g., MADV_DONTNEED it once we drop the PTL, making us trigger a use-after-free on the folio. Link: https://lore.kernel.org/20261015-urgent_fixes-v1-3-42796911043b@kernel.org Fixes: cb6acd01e2e4 ("hugetlbfs: fix races and page leaks during migration") Fixes: 1c9e8def43a3 ("userfaultfd: hugetlbfs: add UFFDIO_COPY support for shared mappings") Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Andrew Morton Reported-by: Lorenzo Stoakes (ARM) Reviewed-by: Lorenzo Stoakes (ARM) Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: Muchun Song Cc: Oscar Salvador Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Adam Litke Cc: Mel Gorman Cc: Rik van Riel Cc: Peter Xu Cc: Kiryl Shutsemau Cc: Mike Rapoport Cc: Josef Bacik Cc: --- mm/hugetlb.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/mm/hugetlb.c~mm-hugetlb-fix-use-after-free-in-hugetlb_mfill_atomic_pte +++ a/mm/hugetlb.c @@ -6489,11 +6489,16 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_ /* No need to invalidate - it was non-present before */ update_mmu_cache(dst_vma, dst_addr, dst_pte); - spin_unlock(ptl); if (!is_continue) folio_set_hugetlb_migratable(folio); if (vm_shared || is_continue) folio_unlock(folio); + + /* + * Hold the PTL until we're done with the folio: the page table owns the + * folio reference now. + */ + spin_unlock(ptl); ret = 0; out: return ret; _ Patches currently in -mm which might be from david@kernel.org are mm-fix-address-wraparound-when-scanning-large-folio-ptes.patch mm-hugetlb-fix-use-after-free-in-hugetlb_mfill_atomic_pte.patch mm-hugetlb-tolerate-uffd-bits-set-without-uffd-for-prot_none-ptes.patch mm-hugetlb-tolerate-uffd_wp-markers-outside-uffd-wp-vmas.patch mm-mremap-fix-calling-fixup_hugetlb_reservations-on-the-wrong-vma.patch arm64-mm-move-__check_safe_pte_update-fix.patch mm-sparse-move-mem_section-init-to-sparse_extreme_init.patch mm-sparse-refactor-sparse_sections_init.patch mm-sparse-move-initialization-of-section-metadata-to-sparse_metadata_init.patch mm-sparse-rename-and-cleanup-sparse_init_nid.patch mm-sparse-cleanup-sparse_init_one_section.patch mm-sparse-rename-__highest_present_section_nr-to-__highest_used_section_nr.patch mm-sparse-remove-pfn_in_present_section.patch mm-sparse-move-__highest_used_section_nr-handling.patch scripts-gdb-mmpy-remove-fallbacks-for-section_has_mem_map-and-section_is_early.patch mm-sparse-remove-section_marked_present.patch mm-sparse-remove-flags-parameter-from-sparse_init_one_section.patch fs-proc-page-clarify-comment-in-get_max_dump_pfn.patch mm-memory_hotplug-drop-config_have_arch_pfn_valid-handling-from-pfn_to_online_page.patch vmcoreinfo-export-section_has_mem_map.patch mm-disallow-ioremaping-ordinary-ram-in-generic_access_phys.patch mm-userfaultfd-only-allocate-anon_vma-in-cow-mappings.patch