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=1793321551; b=nDkgsqUQ6dnV971k45tjLGrjDy84jIJ21MNSevOJQtJDFd3q6mLxTGhpmfW7BY6NGsU/ 5LnTwoVRqKIk0AjgxVLJCnR3LfjkpJAABUTB1jByYU21okTLJYcIf0t6N4+AZq5+ybATQ NgxdzR/J452zk7cXYp8PiBAYEsRljKP9tiwvNZbqgnUSjc27KDer3ENDPMYuzORFNgm85 QCnTJwaQrG7D41LGEw5kXmCV8RODolkAHItcfmHG8kAayu4aHOjo25kPeeVTsYcnWi55d Z7sSth7gyJ0vGH0a4sJgUGYF3bhOd2u8Vo8ennHQfNlNEzPe69G8zlEzNEHstoBX+6A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793321551; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=KTyLfqpPqJPW4V7IJFkvueSZBNZx2dnR4ZDJatY9jgY=; b=sr6oNoygP+E3y9fJ72bw67EG2OdxWf2QdUFkZ0bR/TxjNThE7rvpDT6vRwxZtiwQRfM/ HGnpGXPvXcr29wmOfMObslokgyLgPlFwP7LuOJDS6UWDPcfdbYEFcVYM5wdhPD2Guq6UB 0socp9Aa+E5rmXbKbd2HrYNt/c7qX12+c8RMxmIL9x/rx/resN11Pxd/1bzKMosjfr5WO EBb407vyiK16PZZtXyD55QiPq5/k7QkoC6cHVzLWaDpHfpNsMDRZ1BggFYNJ8GH7lqu3e xJzf/VfCf17sr42GtMzjQEpdvgavSKqSiNX4aAXkLfVFfOORip4u/aKWmSU3PkwIy2w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=vHTynKP4; 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 2E58D606A31A for ; Fri, 30 Oct 2026 00:52:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=vHTynKP4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F67A1F000C1; Fri, 30 Oct 2026 00:52:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1793321550; bh=KTyLfqpPqJPW4V7IJFkvueSZBNZx2dnR4ZDJatY9jgY=; h=Date:To:From:Subject; b=vHTynKP4iRy5nX7XFlLO5k6L9uov2UqmdJPuJLtxT3lWelHq/rRbxhmp7ytng6Feu VycgLWJZzqM28ng05RUDjdB9CgvksSp1uUiFITAwGupVd7TjYsW3j2roeunZDkBaAn aPhjQ6ZMDxiNVckcZIC3a+iMu0o/b5GMxueE/XUM= Date: Thu, 29 Oct 2026 17:52:30 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,surenb@google.com, sshegde@linux.ibm.com,skhan@linuxfoundation.org,rppt@kernel.org, ritesh.list@gmail.com,rdunlap@infradead.org,qi.zheng@linux.dev, osalvador@suse.de,npiggin@gmail.com,mpe@ellerman.id.au,mhocko@suse.com, maddy@linux.ibm.com,ljs@kernel.org,liam@infradead.org,lance.yang@linux.dev, david@kernel.org,corbet@lwn.net,chleroy@kernel.org,muchun.song@linux.dev, akpm@linux-foundation.org From: Andrew Morton Subject: + powerpc-mm-map-shared-vmemmap-tail-pages-as-read-only.patch added to mm-new branch Message-Id: <20261030005230.8F67A1F000C1@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The patch titled Subject: powerpc/mm: map shared vmemmap tail pages as read-only has been added to the -mm mm-new branch. Its filename is powerpc-mm-map-shared-vmemmap-tail-pages-as-read-only.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/powerpc-mm-map-shared-vmemmap-tail-pages-as-read-only.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next 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: Muchun Song Subject: powerpc/mm: map shared vmemmap tail pages as read-only Date: Mon, 19 Oct 2026 17:08:28 +0800 PowerPC radix uses an architecture-specific vmemmap population path for shared tail mappings, so it does not inherit the read-only protection added to the common path. Protect these mappings as well so illegal writes fault instead of corrupting metadata shared by multiple tail pages. Link: https://lore.kernel.org/20261019090830.1917657-3-songmuchun@bytedance.com Signed-off-by: Muchun Song Signed-off-by: Andrew Morton Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Lance Yang Cc: David Hildenbrand Cc: Oscar Salvador Cc: Madhavan Srinivasan Cc: Jonathan Corbet Cc: Lorenzo Stoakes Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Michal Hocko Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Christophe Leroy Cc: Shrikanth Hegde Cc: Shuah Khan Cc: Randy Dunlap Cc: Qi Zheng --- arch/powerpc/mm/book3s64/radix_pgtable.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/powerpc/mm/book3s64/radix_pgtable.c~powerpc-mm-map-shared-vmemmap-tail-pages-as-read-only +++ a/arch/powerpc/mm/book3s64/radix_pgtable.c @@ -1059,6 +1059,9 @@ static pte_t * __meminit radix__vmemmap_ VM_BUG_ON(!PAGE_ALIGNED(addr)); entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL); + /* Map the shared tail page as read-only to catch illegal writes. */ + if (reuse) + entry = pte_wrprotect(entry); set_pte_at(&init_mm, addr, pte, entry); asm volatile("ptesync": : :"memory"); } _ Patches currently in -mm which might be from muchun.song@linux.dev are riscv-mm-fix-hotplug-page-table-destructor-handling.patch riscv-mm-fix-missing-destructor-for-hotplug-pud-tables.patch mm-fix-missing-page-table-destructor-in-pagetable_free.patch arm64-mm-fix-destructor-for-unconstructed-hotplug-page-tables.patch mm-sparse-vmemmap-map-shared-vmemmap-tail-pages-as-read-only.patch powerpc-mm-map-shared-vmemmap-tail-pages-as-read-only.patch mm-hugetlb_vmemmap-remove-vmemmap_wrprotect_hvo.patch mm-hugetlb_vmemmap-remove-hugetlb_vmemmap_optimize_bootmem_folios.patch