Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751735AbdLWHcB (ORCPT ); Sat, 23 Dec 2017 02:32:01 -0500 Received: from mail-pl0-f45.google.com ([209.85.160.45]:39642 "EHLO mail-pl0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747AbdLWHb4 (ORCPT ); Sat, 23 Dec 2017 02:31:56 -0500 X-Google-Smtp-Source: ACJfBosacSgRWkXxNIvbZXX8NZBG9nrNpzh/YaXv9bPHmahUXncX3SWKZMjxIwUuK9A71kXEoHPUYz4yFvcYEvzTGRs= MIME-Version: 1.0 In-Reply-To: <20171223002505.593-1-aarcange@redhat.com> References: <20171222222346.GB28786@zzz.localdomain> <20171223002505.593-1-aarcange@redhat.com> From: Dmitry Vyukov Date: Sat, 23 Dec 2017 08:31:35 +0100 Message-ID: Subject: Re: [PATCH 0/1] Re: kernel BUG at fs/userfaultfd.c:LINE! To: Andrea Arcangeli Cc: Andrew Morton , Eric Biggers , Mike Rapoport , LKML , linux-fsdevel@vger.kernel.org, Al Viro , Linux-MM , syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1175 Lines: 39 On Sat, Dec 23, 2017 at 1:25 AM, Andrea Arcangeli wrote: > Hello, > > Thanks for the CC, I'm temporarily very busy so if there's something > urgent, safer to CC. Hi, syzbot uses get_maintainer.pl and for fs/userfaultfd.c you are not there, so if you want to be CCed please add yourself to MAINTAINERS. > 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(-) The original report footer was stripped, so: Please credit me with: Reported-by: syzbot and we also need to tell syzbot about the fix with: #syz fix: userfaultfd: clear the vma->vm_userfaultfd_ctx if UFFD_EVENT_FORK fails