From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f72.google.com (mail-oi0-f72.google.com [209.85.218.72]) by kanga.kvack.org (Postfix) with ESMTP id 98D036B0260 for ; Fri, 22 Dec 2017 19:25:09 -0500 (EST) Received: by mail-oi0-f72.google.com with SMTP id u126so13078435oif.23 for ; Fri, 22 Dec 2017 16:25:09 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id j68si7584777otj.478.2017.12.22.16.25.08 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 22 Dec 2017 16:25:08 -0800 (PST) From: Andrea Arcangeli 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> Sender: owner-linux-mm@kvack.org List-ID: 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 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(-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org