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=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 4350EC28CBC for ; Wed, 6 May 2020 17:22:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F33A20736 for ; Wed, 6 May 2020 17:22:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="lD8zIVQr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729714AbgEFRWQ (ORCPT ); Wed, 6 May 2020 13:22:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728110AbgEFRWO (ORCPT ); Wed, 6 May 2020 13:22:14 -0400 Received: from mail-qt1-x84a.google.com (mail-qt1-x84a.google.com [IPv6:2607:f8b0:4864:20::84a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFC33C061A0F for ; Wed, 6 May 2020 10:22:12 -0700 (PDT) Received: by mail-qt1-x84a.google.com with SMTP id h1so3596777qtu.13 for ; Wed, 06 May 2020 10:22:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=ns5wyg0cVDVk/wsS7IuEAG4E9K0ywHpqVyUHPZtDgoo=; b=lD8zIVQrDYNDHbqQniGarHiRp/7jkovViyyqRShGjw9CpIiJoJYRtoF8aIKEpdUQ4H nIQNldLWiyyEV4TOREBFdI7psqpQg870pL35Z9F4/ZXYDIHEtn/V00fUsBZi1EhZvTF4 mqdas27rYVNtPWyCjYbm6xRdn+njQ3wrRW6+YgzOwB2DJaFheGpaL+C8bfPphYs7CXjx rSrPIOYwzhOQItBmAlmwBRfWagY2inbJhESaBWALFoq38uqQwlDcTJc+OmF6j6UbqHvV joz5z57fdbWVYzsTSnWgV4Q6fthh0JL/APrz9YYbuUmomFf+XyvOJPVtK5SedX0WXxb2 SM+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=ns5wyg0cVDVk/wsS7IuEAG4E9K0ywHpqVyUHPZtDgoo=; b=GquSr8zJrcNzmWikPsqbxx9E+HyeC/gWy2A+/7uV98pFBb4F3wv/94ZccWSU9VPoDo NaR7F9cyqPs5jqj48fXRDeLJdRpXYTrZRVnnuzCx2Sm0lY0XkDdlBGC7mCxzeEDbclIz Ni+DPEc3toZAqnxkrygnfuDAJmZvyklXNQ0Py2L9D6vkjh7bvk5I+ITS+1HyofU35pqZ jnDkN82Vn97DEeSb1RI/fabSq5em3L4Xh4X6EQLRo5zcTCWZeR4dOM+tj/DM23E68XI/ ftV+rWmf+bvqyA9wYgd9DBPDyPAB34Dojo8EsfKs27nPDHDCBMUMD9ngtw1u7L68eS9a L+Dw== X-Gm-Message-State: AGi0PuZ2ZnM5CTwqrHmGRhEoJktvJFOkY6vOIE/mcw2/i0TsrWw7LYZs HeThbFQNDmYzCfwa43r6TgerCH17enD5 X-Google-Smtp-Source: APiQypIVYXz61krSfHTd7V4z7gh8F2h0wQZiceqNuEwVkeU7chmOYzYiQhfzMOE61tPVGBUSBVwriugRb7dH X-Received: by 2002:a0c:8b48:: with SMTP id d8mr9461703qvc.195.1588785732019; Wed, 06 May 2020 10:22:12 -0700 (PDT) Date: Wed, 6 May 2020 10:21:58 -0700 Message-Id: <20200506172158.218366-1-bgeffon@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.26.2.526.g744177e7f7-goog Subject: [PATCH] userfaultfd: fix remap event with MREMAP_DONTUNMAP. From: Brian Geffon To: Andrew Morton Cc: "Michael S . Tsirkin" , Brian Geffon , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrea Arcangeli , Sonny Rao , Minchan Kim , Joel Fernandes , "Kirill A . Shutemov" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A user is not required to set a new address when using MREMAP_DONTUNMAP as it can be used without MREMAP_FIXED. When doing so the remap event will use new_addr which may not have been set and we didn't propagate it back other then in the return value of remap_to. Because ret is always the new address it's probably more correct to use it rather than new_addr on the remap_event_complete call, and it resolves this bug. Signed-off-by: Brian Geffon --- mm/mremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mremap.c b/mm/mremap.c index c881abeba0bf..6aa6ea605068 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -794,7 +794,7 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, if (locked && new_len > old_len) mm_populate(new_addr + old_len, new_len - old_len); userfaultfd_unmap_complete(mm, &uf_unmap_early); - mremap_userfaultfd_complete(&uf, addr, new_addr, old_len); + mremap_userfaultfd_complete(&uf, addr, ret, old_len); userfaultfd_unmap_complete(mm, &uf_unmap); return ret; } -- 2.26.2.526.g744177e7f7-goog