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 D41FFC28CBC for ; Wed, 6 May 2020 17:28:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9376B20746 for ; Wed, 6 May 2020 17:28:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="jUbD5UxL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9376B20746 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 25AF28E0005; Wed, 6 May 2020 13:28:26 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 20A1D8E0003; Wed, 6 May 2020 13:28:26 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 121118E0005; Wed, 6 May 2020 13:28:26 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0242.hostedemail.com [216.40.44.242]) by kanga.kvack.org (Postfix) with ESMTP id ECCFA8E0003 for ; Wed, 6 May 2020 13:28:25 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id B5AAF180AD80F for ; Wed, 6 May 2020 17:28:25 +0000 (UTC) X-FDA: 76786978170.20.spoon10_f57083761d0e X-HE-Tag: spoon10_f57083761d0e X-Filterd-Recvd-Size: 4086 Received: from mail-il1-f193.google.com (mail-il1-f193.google.com [209.85.166.193]) by imf24.hostedemail.com (Postfix) with ESMTP for ; Wed, 6 May 2020 17:28:25 +0000 (UTC) Received: by mail-il1-f193.google.com with SMTP id e8so764099ilm.7 for ; Wed, 06 May 2020 10:28:25 -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=NkDAllS86i6Alq3z4SNts3BijlYyvPsoIcv+ue8aWg8=; b=jUbD5UxLSRV1oJtdrH8l4vkJlOdaFnoDCwHggnvcWuO50ybSq4H19Kfsv+J6OoCZBZ sDkT/r8bk5c9iq3n9GXxmVUfGvmok81rpK8dWKefeIZkGtgqLk0ORLppCUm/Z83KwTqA pblZ2lMavzUAYyoBMy9esRjxeFbWN2wedYEoQ= 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=NkDAllS86i6Alq3z4SNts3BijlYyvPsoIcv+ue8aWg8=; b=rDtgV2QQ6H8ECDdv8E++Axas0d5l8WdiBDjUHim1ltlc3ocrzvXPw8gfUyFc/sli+t VU5GYjFpcrhVPyRSFl6rwvZUzYCvyEvOIltniuCI3/u5uW//BVx0pCfB0rNUBjBNwIDR K+nnhugYipYftUoaJl3IqJVdsoCFZpPiWQwIYmf2syRqzQ7lw+WfQqRDkt8fOjAGJTaE /ejdoSjxiCmLuDGhs6l50DzW5zWHYaBcokoGC2NHlLqiKX6+JZE1l6bfYf/hSqgFEj16 E09urFNUv5EAUPfbMWIBDareHRSey/D81GMXtxLxYDSQ0O+gzPJ5T2MGmx6ZBV6QKVFA i7nw== X-Gm-Message-State: AGi0PuamSgvWNE5EQRH/aMkTSgdfoGHopepKOdfbQqmvimIOaLGqHEIO RcqJw7UoHq4DGMzZVNhefcaRPLS2csz4rtYYklBCbA== X-Google-Smtp-Source: APiQypIMN4yue9z7yuqXCPD1oqgkfK+58GpdD8IRN9D/xWCQKzyTsf/cozLhBZXGqmf1/i2LcTY2+329eepl/SQwcu0= X-Received: by 2002:a92:3509:: with SMTP id c9mr10343042ila.262.1588786104558; Wed, 06 May 2020 10:28:24 -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 13:28:13 -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=0.000000, 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. > Does it need Fixes: tag, and CC to stable? Going into a stable kernel will mean the stable kernel merges into ChromeOS also gets it. thanks, - Joel > 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 >