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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 D5B6DC28CBC for ; Thu, 7 May 2020 01:06:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 955942082E for ; Thu, 7 May 2020 01:06:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="UhtGXIkC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 955942082E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joelfernandes.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1EEED900007; Wed, 6 May 2020 21:06:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 19EB8900004; Wed, 6 May 2020 21:06:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0B47E900007; Wed, 6 May 2020 21:06:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0236.hostedemail.com [216.40.44.236]) by kanga.kvack.org (Postfix) with ESMTP id E9E6E900004 for ; Wed, 6 May 2020 21:06:49 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id B59E3BEF0 for ; Thu, 7 May 2020 01:06:49 +0000 (UTC) X-FDA: 76788133338.08.rate89_58b1809391352 X-HE-Tag: rate89_58b1809391352 X-Filterd-Recvd-Size: 4120 Received: from mail-io1-f67.google.com (mail-io1-f67.google.com [209.85.166.67]) by imf28.hostedemail.com (Postfix) with ESMTP for ; Thu, 7 May 2020 01:06:49 +0000 (UTC) Received: by mail-io1-f67.google.com with SMTP id c2so4316361iow.7 for ; Wed, 06 May 2020 18:06:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=of3KfhSUdjcRaAhhtS98nALCb0SeCwXToKZ3bm5aVW0=; b=UhtGXIkCMYXfzHwRayibTEkrHWHkG1XzIQ5y1BMZWH8G+drB3N5LHYxjP1d+TuV08f NJKEl1hgPTTnGXlFYqwun3zGwXx1G5gKO7J+tEu+ZX+IgVbd8hWfD7SBDJB59pKA/s/4 FTagE+4BCKWlq95uTeYFK1eCljj71lUhvBcqE= 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=of3KfhSUdjcRaAhhtS98nALCb0SeCwXToKZ3bm5aVW0=; b=EMOJ46IwlwKOugpx2jFHrV3QXP9z+ASbw0g9rgeAwlweWveQOzbc2ifBW7PE0JwHcW hVRyGOBFsy1XpAWDTnrZR+hubLNBtB6L1ozNxIZq7Nl9Dx84YoKp4B+9tCGKdZ5z/c86 ZevF2quP18dcxcDQzHiO4GGBNlq+X0CU6LxutNPxWi1/EkZHzDUOcsGgv/srEE9VhR9m TKcF+uC8y33ypJtG+W8ILl1O0yI7a+ZCRVCkJKSRJhKG5TitjrWIArDpwpjbPpzSQ5j+ UlR6KY2tM3djqNARPXo381CxXXTfsPBSPrCd5bngPjk6cAxTHeJint/x/BRuc3DQ4l4n paEw== X-Gm-Message-State: AGi0Pub602zw1FzDD0HruCpDC0pHdFQ6mwBmgRLs1FAS4XHWiUfnyIhH 4PI0ZnixtEJh+zWZhs7EBELt0LA11ze+pyUwrZv18w== X-Google-Smtp-Source: APiQypIhPDD2VryfsIP+QJWr3Q6Ie5B6ZGqJNucbPF/WIouLSZ5535SkF1Dox4SaU2fr+Fd//5tpVpHC7B1MreVXAAo= X-Received: by 2002:a02:a68e:: with SMTP id j14mr11373661jam.86.1588813608862; Wed, 06 May 2020 18:06:48 -0700 (PDT) MIME-Version: 1.0 References: <20200506172158.218366-1-bgeffon@google.com> In-Reply-To: <20200506172158.218366-1-bgeffon@google.com> From: Joel Fernandes Date: Wed, 6 May 2020 21:06:37 -0400 Message-ID: Subject: Re: [PATCH] userfaultfd: fix remap event with MREMAP_DONTUNMAP. To: Brian Geffon 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=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, May 6, 2020 at 1:22 PM Brian Geffon wrote: > > 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); Not super familiar with this code, but thought I'd ask, does ret need to be checked for -ENOMEM before calling mremap_userfaultfd_complete? Sorry if I missed something. Thanks, - Joel > userfaultfd_unmap_complete(mm, &uf_unmap); > return ret; > } > -- > 2.26.2.526.g744177e7f7-goog >