From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id B68F76B02FD for ; Thu, 27 Jul 2017 02:27:10 -0400 (EDT) Received: by mail-wm0-f72.google.com with SMTP id c184so17720607wmd.6 for ; Wed, 26 Jul 2017 23:27:10 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id b58si15317246wra.454.2017.07.26.23.27.09 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 26 Jul 2017 23:27:09 -0700 (PDT) Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v6R6O3nH080150 for ; Thu, 27 Jul 2017 02:27:08 -0400 Received: from e06smtp10.uk.ibm.com (e06smtp10.uk.ibm.com [195.75.94.106]) by mx0b-001b2d01.pphosted.com with ESMTP id 2by364t79a-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 27 Jul 2017 02:27:07 -0400 Received: from localhost by e06smtp10.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 27 Jul 2017 07:27:06 +0100 From: Mike Rapoport Subject: [PATCH] userfaultfd_zeropage: return -ENOSPC in case mm has gone Date: Thu, 27 Jul 2017 09:26:59 +0300 Message-Id: <1501136819-21857-1-git-send-email-rppt@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Andrea Arcangeli , "Dr. David Alan Gilbert" , Pavel Emelyanov , linux-mm , lkml , Mike Rapoport , stable@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. Cc: stable@vger.kernel.org Fixes: 96333187ab162 ("userfaultfd_copy: return -ENOSPC in case mm has gone") Signed-off-by: Mike Rapoport --- Unfortunately, I've overlooked userfaultfd_zeropage when I updated userfaultd_copy :( fs/userfaultfd.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index cadcd12a3d35..2d8c2d848668 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1643,6 +1643,8 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx, ret = mfill_zeropage(ctx->mm, uffdio_zeropage.range.start, uffdio_zeropage.range.len); mmput(ctx->mm); + } else { + return -ENOSPC; } if (unlikely(put_user(ret, &user_uffdio_zeropage->zeropage))) return -EFAULT; -- 2.7.4 -- 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