From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F1ED8256C84 for ; Mon, 9 Mar 2026 10:24:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773051843; cv=none; b=ZGX3hlewNmsQU6qF69uzrqaXVGqv/PF4JgxPqazFnx7rHr5ZAT7Vi3k4D2kolRKqUTPLT5C282NTsEaFrcaAVjqmyfHvATyaeKXwwW4+7XoaUlqJG+KLMrGkT3CnQTsRY100NbUzvZH6sqIx9oGzHSrq1Lri8lNAbdB58r3DUNo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773051843; c=relaxed/simple; bh=gDg1+cPGKwnqjk4fys/WNl6PJnSsivrlWmNoZKK8eJM=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=R89FZCm/jr0HuNn3Ospr2kumBIVJy1ML9KvsSw8J3UIdgEDyH06tqf04j8o4h+oebtfDyb6kbBP/R1qgpLg2769+1jp3XcTkOSCrHLZRc5UBFUco2liWpR202oQLI0VoHiLS5RFqB40VPRlRcCd8MZx0WZIHLPDcbayGhNnfqkI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=T96cRc+t; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="T96cRc+t" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6615BC4CEF7; Mon, 9 Mar 2026 10:24:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773051842; bh=gDg1+cPGKwnqjk4fys/WNl6PJnSsivrlWmNoZKK8eJM=; h=Subject:To:Cc:From:Date:From; b=T96cRc+tGaM8oXFULLGnPYhLU2ef9GEzmm4TVhYydsgGLKnEyjLAROVin5U4vPbV3 hzYVoZWW2W8qXverSnDbrYd7ko7EaIBC4l9PekInepglh+6o7rgXBfWJsjf+HbXHyW TdgQvdGJachClYgv7VNhwdbMQU1edT7rJhFWmZAY= Subject: FAILED: patch "[PATCH] mm: thp: deny THP for files on anonymous inodes" failed to apply to 6.12-stable tree To: kartikey406@gmail.com,Kartikey406@gmail.com,ackerleytng@google.com,akpm@linux-foundation.org,baohua@kernel.org,baolin.wang@linux.alibaba.com,david@kernel.org,dev.jain@arm.com,i@maskray.me,lance.yang@linux.dev,liam.howlett@oracle.com,lorenzo.stoakes@oracle.com,npache@redhat.com,ryan.roberts@arm.com,shy828301@gmail.com,stable@vger.kernel.org,ziy@nvidia.com Cc: From: Date: Mon, 09 Mar 2026 11:24:00 +0100 Message-ID: <2026030900-shore-output-ef28@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x dd085fe9a8ebfc5d10314c60452db38d2b75e609 # git commit -s git send-email --to '' --in-reply-to '2026030900-shore-output-ef28@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From dd085fe9a8ebfc5d10314c60452db38d2b75e609 Mon Sep 17 00:00:00 2001 From: Deepanshu Kartikey Date: Sat, 14 Feb 2026 05:45:35 +0530 Subject: [PATCH] mm: thp: deny THP for files on anonymous inodes file_thp_enabled() incorrectly allows THP for files on anonymous inodes (e.g. guest_memfd and secretmem). These files are created via alloc_file_pseudo(), which does not call get_write_access() and leaves inode->i_writecount at 0. Combined with S_ISREG(inode->i_mode) being true, they appear as read-only regular files when CONFIG_READ_ONLY_THP_FOR_FS is enabled, making them eligible for THP collapse. Anonymous inodes can never pass the inode_is_open_for_write() check since their i_writecount is never incremented through the normal VFS open path. The right thing to do is to exclude them from THP eligibility altogether, since CONFIG_READ_ONLY_THP_FOR_FS was designed for real filesystem files (e.g. shared libraries), not for pseudo-filesystem inodes. For guest_memfd, this allows khugepaged and MADV_COLLAPSE to create large folios in the page cache via the collapse path, but the guest_memfd fault handler does not support large folios. This triggers WARN_ON_ONCE(folio_test_large(folio)) in kvm_gmem_fault_user_mapping(). For secretmem, collapse_file() tries to copy page contents through the direct map, but secretmem pages are removed from the direct map. This can result in a kernel crash: BUG: unable to handle page fault for address: ffff88810284d000 RIP: 0010:memcpy_orig+0x16/0x130 Call Trace: collapse_file hpage_collapse_scan_file madvise_collapse Secretmem is not affected by the crash on upstream as the memory failure recovery handles the failed copy gracefully, but it still triggers confusing false memory failure reports: Memory failure: 0x106d96f: recovery action for clean unevictable LRU page: Recovered Check IS_ANON_FILE(inode) in file_thp_enabled() to deny THP for all anonymous inode files. Link: https://syzkaller.appspot.com/bug?extid=33a04338019ac7e43a44 Link: https://lore.kernel.org/linux-mm/CAEvNRgHegcz3ro35ixkDw39ES8=U6rs6S7iP0gkR9enr7HoGtA@mail.gmail.com Link: https://lkml.kernel.org/r/20260214001535.435626-1-kartikey406@gmail.com Fixes: 7fbb5e188248 ("mm: remove VM_EXEC requirement for THP eligibility") Signed-off-by: Deepanshu Kartikey Reported-by: syzbot+33a04338019ac7e43a44@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=33a04338019ac7e43a44 Tested-by: syzbot+33a04338019ac7e43a44@syzkaller.appspotmail.com Tested-by: Lance Yang Acked-by: David Hildenbrand (Arm) Reviewed-by: Barry Song Reviewed-by: Ackerley Tng Tested-by: Ackerley Tng Reviewed-by: Lorenzo Stoakes Cc: Baolin Wang Cc: Dev Jain Cc: Fangrui Song Cc: Liam Howlett Cc: Nico Pache Cc: Ryan Roberts Cc: Yang Shi Cc: Zi Yan Cc: Signed-off-by: Andrew Morton diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d4ca8cfd7f9d..8e2746ea74ad 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -94,6 +94,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma) inode = file_inode(vma->vm_file); + if (IS_ANON_FILE(inode)) + return false; + return !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode); }