From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:45358 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757885AbdLRN0r (ORCPT ); Mon, 18 Dec 2017 08:26:47 -0500 Subject: Patch "userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE" has been added to the 4.9-stable tree To: aarcange@redhat.com, akpm@linux-foundation.org, alexander.levin@verizon.com, dvyukov@google.com, gregkh@linuxfoundation.org, kirill@shutemov.name, torvalds@linux-foundation.org Cc: , From: Date: Mon, 18 Dec 2017 14:24:08 +0100 Message-ID: <1513603448130222@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: userfaultfd-shmem-__do_fault-requires-vm_fault_nopage.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Mon Dec 18 14:12:34 CET 2017 From: Andrea Arcangeli Date: Thu, 9 Mar 2017 16:16:28 -0800 Subject: userfaultfd: shmem: __do_fault requires VM_FAULT_NOPAGE From: Andrea Arcangeli [ Upstream commit 6bbc4a4144b1a69743022ac68dfaf6e7d993abb9 ] __do_fault assumes vmf->page has been initialized and is valid if VM_FAULT_NOPAGE is not returned by vma->vm_ops->fault(vma, vmf). handle_userfault() in turn should return VM_FAULT_NOPAGE if it doesn't return VM_FAULT_SIGBUS or VM_FAULT_RETRY (the other two possibilities). This VM_FAULT_NOPAGE case is only invoked when signal are pending and it didn't matter for anonymous memory before. It only started to matter since shmem was introduced. hugetlbfs also takes a different path and doesn't exercise __do_fault. Link: http://lkml.kernel.org/r/20170228154201.GH5816@redhat.com Signed-off-by: Andrea Arcangeli Reported-by: Dmitry Vyukov Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/userfaultfd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -419,7 +419,7 @@ int handle_userfault(struct fault_env *f * in such case. */ down_read(&mm->mmap_sem); - ret = 0; + ret = VM_FAULT_NOPAGE; } } Patches currently in stable-queue which might be from aarcange@redhat.com are queue-4.9/userfaultfd-selftest-vm-allow-to-build-in-vm-directory.patch queue-4.9/userfaultfd-shmem-__do_fault-requires-vm_fault_nopage.patch