From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750985AbdA0XLd (ORCPT ); Fri, 27 Jan 2017 18:11:33 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:58357 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750710AbdA0XL0 (ORCPT ); Fri, 27 Jan 2017 18:11:26 -0500 From: Mike Rapoport To: Andrew Morton Cc: Andrea Arcangeli , "Dr. David Alan Gilbert" , Hillf Danton , Mike Kravetz , Pavel Emelyanov , Linux-MM , LKML , Mike Rapoport Subject: [PATCH v2 5/5] userfaultfd_copy: return -ENOSPC in case mm has gone Date: Fri, 27 Jan 2017 20:44:33 +0200 X-Mailer: git-send-email 1.9.1 In-Reply-To: <1485542673-24387-1-git-send-email-rppt@linux.vnet.ibm.com> References: <1485542673-24387-1-git-send-email-rppt@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 X-Content-Scanned: Fidelis XPS MAILER x-cbid: 17012718-0016-0000-0000-000004339113 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17012718-0017-0000-0000-0000263FFFA1 Message-Id: <1485542673-24387-6-git-send-email-rppt@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-01-27_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1612050000 definitions=main-1701270182 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the non-cooperative userfaultfd case, the process exit may race with outstanding mcopy_atomic called by the uffd monitor. Returning -ENOSPC instead of -EINVAL when mm is already gone will allow uffd monitor to distinguish this case from other error conditions. Signed-off-by: Mike Rapoport Acked-by: Hillf Danton --- fs/userfaultfd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 839ffd5..6587f40 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1603,6 +1603,8 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx, ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src, uffdio_copy.len); mmput(ctx->mm); + } else { + return -ENOSPC; } if (unlikely(put_user(ret, &user_uffdio_copy->copy))) return -EFAULT; -- 1.9.1