Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757048AbdLWAZL (ORCPT ); Fri, 22 Dec 2017 19:25:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44188 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752448AbdLWAZH (ORCPT ); Fri, 22 Dec 2017 19:25:07 -0500 From: Andrea Arcangeli To: Andrew Morton , Eric Biggers Cc: Mike Rapoport , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com Subject: [PATCH 0/1] Re: kernel BUG at fs/userfaultfd.c:LINE! Date: Sat, 23 Dec 2017 01:25:04 +0100 Message-Id: <20171223002505.593-1-aarcange@redhat.com> In-Reply-To: <20171222222346.GB28786@zzz.localdomain> References: <20171222222346.GB28786@zzz.localdomain> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Sat, 23 Dec 2017 00:25:07 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 660 Lines: 23 Hello, Thanks for the CC, I'm temporarily very busy so if there's something urgent, safer to CC. This passed both testcases, the hard part was already done. I'm glad there was nothing wrong in the previous fix that had to be redone. Simply we forgot to undo the vma->vm_userfaultfd_ctx = NULL after aborting the new child uffd ctx, the original code of course didn't do that either. Having just seen this issue, this isn't very well tested. Thank you, Andrea Andrea Arcangeli (1): userfaultfd: clear the vma->vm_userfaultfd_ctx if UFFD_EVENT_FORK fails fs/userfaultfd.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)