From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A89DDC28CBC for ; Thu, 7 May 2020 01:11:56 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 609EA2075E for ; Thu, 7 May 2020 01:11:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="FHpyZjmU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 609EA2075E Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E954D900007; Wed, 6 May 2020 21:11:55 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E443B900004; Wed, 6 May 2020 21:11:55 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D0C2F900007; Wed, 6 May 2020 21:11:55 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0223.hostedemail.com [216.40.44.223]) by kanga.kvack.org (Postfix) with ESMTP id B5BC1900004 for ; Wed, 6 May 2020 21:11:55 -0400 (EDT) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 7637E824559C for ; Thu, 7 May 2020 01:11:55 +0000 (UTC) X-FDA: 76788146190.15.war91_852cfcc8b6315 X-HE-Tag: war91_852cfcc8b6315 X-Filterd-Recvd-Size: 3624 Received: from mail-ed1-f66.google.com (mail-ed1-f66.google.com [209.85.208.66]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Thu, 7 May 2020 01:11:55 +0000 (UTC) Received: by mail-ed1-f66.google.com with SMTP id p16so3842295edm.10 for ; Wed, 06 May 2020 18:11:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=BHSYd56y/P/AUtkor9mWMhsnnvoYQniivekGDDl33VE=; b=FHpyZjmUtqznPles3ZOTSsJgpog1COpvoPMjD4c8pV3qSNINY3kTWbwgeD/3h14vwQ u6+VJrr41RD7Cx7piBakvcqtkTnpXlg7a3XnQKnc7zDPWgC8wzc8O6Zlg0qEWpdoIdP9 xfYDLRUDIJLvol0oqXI+WWsJ4+pebSiR5PWtk09UPNnK9Xy+ZKNh2SEQnPc2cuUtSh53 Dqd+3WO2tSpZl6wg/vNecAc1LHLQxjU0i/sWs5x+aHCa09JgabVTNo9IcdVncaBrYfK8 FlNC21LUJSdWTDOAxByum/NdwDE40+ga7HxCQvzdhNY9wLP+VZ83km3qt1TDd81/z/TS tRrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=BHSYd56y/P/AUtkor9mWMhsnnvoYQniivekGDDl33VE=; b=qlHVGT6fd00MCh6n8VD8RtF7GZfb7vdlJMDEVp34qzL4D98NzBEDlWLgNvPjPZWbEn oXDPyqc7w5IxyTpXIqXG1RyuweyUsrUBuS8eboVpRyN44XriAKbSjTZEQlxi6LyLMRFd c9+uHmB/gPM7Q3BENodnF364Mos5YBriUgPbYD3EoDWJiRZbXbA+/xLRZZ6aurhih7j6 yDC2JS0vPr7oaM5fuohydYucgE4A3TMWW6p0heV8J6c0QTaGgoA+TxMvel5BAME1Kv4H gi3+m520jlF230W8fkhCOdO0iO2Uco3NE9nlb5ktKZNZ58L41/imTlnmXLAxldBqsNeI tqTA== X-Gm-Message-State: AGi0PuY2ho/LesZEhK6Yww30I+RjHSh8i9wFsRW5MNwATQG+ei2IOUn3 RlQireppDCGyiLa6Yj7wMN1wKOwTzy9HbcYI4xDTgg== X-Google-Smtp-Source: APiQypJi40Eci4aiL9uRsmX+8iVMgQz9PK0rFJdqmVeRclEGT3sprJ6Ip6a/6WRwPbVZiZPzz88EuAPuMw3ojMIJwNo= X-Received: by 2002:a50:eb0a:: with SMTP id y10mr9645097edp.312.1588813913603; Wed, 06 May 2020 18:11:53 -0700 (PDT) MIME-Version: 1.0 References: <20200506172158.218366-1-bgeffon@google.com> In-Reply-To: From: Brian Geffon Date: Wed, 6 May 2020 18:11:17 -0700 Message-ID: Subject: Re: [PATCH] userfaultfd: fix remap event with MREMAP_DONTUNMAP. To: Joel Fernandes Cc: Andrew Morton , "Michael S . Tsirkin" , LKML , linux-mm , Andrea Arcangeli , Sonny Rao , Minchan Kim , "Kirill A . Shutemov" Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.006413, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > > - mremap_userfaultfd_complete(&uf, addr, new_addr, old_len); > > + mremap_userfaultfd_complete(&uf, addr, ret, old_len); > > Not super familiar with this code, but thought I'd ask, does ret > to be checked for -ENOMEM before calling mremap_userfaultfd_complete? > Sorry if I missed something. No, mremap_userfaultfd_complete will do a check similar to offset_in_page() by checking the page mask. It does (to & ~PAGE_MASK) to check for a non-aligned "to" value, so we're good. Additionally, earlier in the process then ctx will be null because we will have never called mremap_userfaultfd_prep, and mremap_userfaultfd_complete will check if there is a context before proceeding. Brian