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=-6.1 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1, 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 64705C76196 for ; Tue, 16 Jul 2019 16:08:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B3642173C for ; Tue, 16 Jul 2019 16:08:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="OD8jzeif" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387958AbfGPQId (ORCPT ); Tue, 16 Jul 2019 12:08:33 -0400 Received: from mail-io1-f67.google.com ([209.85.166.67]:46948 "EHLO mail-io1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388058AbfGPQIc (ORCPT ); Tue, 16 Jul 2019 12:08:32 -0400 Received: by mail-io1-f67.google.com with SMTP id i10so40740275iol.13 for ; Tue, 16 Jul 2019 09:08:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=2Do517kmLX0/AbsjIptJHF+WgkfT9EAU1+uYSgocd18=; b=OD8jzeifgewgqWGZ67bSF6pUYQTISn1eNZ0jVIJg1dunQPNbgn2mPaWegO1fT2FnKX snZyKcZSA+onK1zQVhDVSD/oL61Xe+ICpvdedmTCdyMgs6PTGu1sSZ+qHref8oQi0Pm1 Y7hO//QXUeoLwWUsQsflE+SArFAuxZisIjQVhDca2MzaxwMGqSXtQ5Uo6TSGlcaPJ23d QaSfkMO4aF7Lw557MU+ruINuhuA3yaL7p7ANEcD538R5JV4q5En/bn2IHwb5etm2xg0P cReUuCqZhiJu6wFPr3U0WVD/gP0Xd4HebFlzSJ9BCvAEkcbTMtsJZKwrAhHVVVFZ3B/a 1TAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=2Do517kmLX0/AbsjIptJHF+WgkfT9EAU1+uYSgocd18=; b=JOss0OkN2L3HanR1Ac2vE7KmRSs0GuVRHN9J0+F1FP3ErICGgB0OsPMtAmN2IMe7UC hrXApeSdje6RHCkYwX0QWXHi8C6eEzbxcm0CVxVP1wENFB4+4dYwgIFqnoVRd+q70TCn l8zXBXOGkXS2Bmw1ybPPXEv6XVMXFXHWOLBOYfARN+WQKDa4czN2pe5gZcw6UJZhiBuk UE9mDs+GUM2yiMULPTGvDdEAi4j7HTUz+k41v1bNOF2yvs2hoIzPPDmR9bL81EK4hv63 w1Qx6LXi1Utj5LYY/tvwTOdfkRiAB2I+vQ2x7p11aw6FpIwv9ScZJfOl6EsN+F+M45Ha K5Rw== X-Gm-Message-State: APjAAAX7cotKfGJ9CZmafySwM0uZD93S7Yas7LaUJJ1q/SapnOasykid 2RA2fRdp8iPgB/AER3ddcSuozw== X-Google-Smtp-Source: APXvYqy2UY1Az05aEyIlQ6vJPmmEBF7PV01YxKa+o/A6WTJqZUVLyX5dcKmJ1+hiLMQ3qaIZ5tNkPA== X-Received: by 2002:a02:230a:: with SMTP id u10mr35398925jau.117.1563293311353; Tue, 16 Jul 2019 09:08:31 -0700 (PDT) Received: from google.com ([2620:15c:183:200:855f:8919:84a7:4794]) by smtp.gmail.com with ESMTPSA id s3sm18401674iob.49.2019.07.16.09.08.30 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 16 Jul 2019 09:08:30 -0700 (PDT) Date: Tue, 16 Jul 2019 10:08:28 -0600 From: Ross Zwisler To: Sasha Levin Cc: Ross Zwisler , stable@vger.kernel.org, Dave Airlie , Guenter Roeck Subject: Re: [v4.14.y PATCH 0/2] fix drm/udl use-after-free error Message-ID: <20190716160828.GA13008@google.com> References: <20190715193618.24578-1-zwisler@google.com> <20190716011308.GA1943@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190716011308.GA1943@sasha-vm> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Jul 15, 2019 at 09:13:08PM -0400, Sasha Levin wrote: > On Mon, Jul 15, 2019 at 01:36:16PM -0600, Ross Zwisler wrote: > > This patch is the second in this series, and requires the first patch as > > a dependency. This series apples cleanly to v4.14.133. > > Hm, we don't need ac3b35f11a06 here? Why not? I'd love to document that > with the backport. Nope, we don't need that patch in the v4.14 backport. In v4.19.y we have two functions, drm_dev_put() and drm_dev_unref(), which are aliases for one another (drm_dev_unref() just calls drm_dev_put()). drm_dev_unref() is the older of the two, and was introduced back in v4.0. drm_dev_put() was introduced in v4.15 with 9a96f55034e41 drm: introduce drm_dev_{get/put} functions and slowly callers were moved from the old name (_unref) to the new name (_put). The patch you mentioned, ac3b35f11a06, is one such patch where we are replacing a drm_dev_unref() call with a drm_dev_put() call. This doesn't have a functional change, but was necessary so that the third patch in the v4.19.y series I sent would apply cleanly. For the v4.14.y series, though, the drm_dev_put() function hasn't yet been defined and everyone is still using drm_dev_unref(). So, we don't need a backport of ac3b35f11a06, and I also had a small backport change in the last patch of the v4.14.y series where I had to change a drm_dev_put() call with a drm_dev_unref() call. Just for posterity, the drm_dev_unref() calls were eventually all changed to drm_dev_put() in v5.0, and drm_dev_unref() was removed entirely. That happened with the following two patches: 808bad32ea423 drm: replace "drm_dev_unref" function with "drm_dev_put" ba1d345401476 drm: remove deprecated "drm_dev_unref" function