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=-6.3 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 9C172C433E1 for ; Sun, 31 May 2020 16:01:51 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6FB7D207C4 for ; Sun, 31 May 2020 16:01:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="uH91HHXP" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6FB7D207C4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6D64089F99; Sun, 31 May 2020 16:01:50 +0000 (UTC) Received: from mail-ej1-x641.google.com (mail-ej1-x641.google.com [IPv6:2a00:1450:4864:20::641]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6E6C289F99; Sun, 31 May 2020 16:01:49 +0000 (UTC) Received: by mail-ej1-x641.google.com with SMTP id y13so6898266eju.2; Sun, 31 May 2020 09:01:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=C6Pcc0KCAqq6UnYDDdgdeBt1kbXH4HvttEs94ToLTKU=; b=uH91HHXPEQsuatgZeJhtxIV9ISRL6OUnl1+5+9aeUjbBFVxjp1Qy85TtGShtR0rZ69 rQpFZ5wBUCv25a3eoy76VkpKA7c7VFBBO2hNLZST/wBBhxVDkIpo61XYHtC7PAByihCE fhsuM/n2S1qMDnVXwl07QOuqdAW0MAgdkHto4zbnakiO+k4UvF1+FcbXz2Ul7yTEuuuw KjhtsbdNml4E2A9YllFiqJRkHOiKWduSCidFivH1vrjza8tm9rHD0RKL9FeINh5nF/lQ zLRSpe8S355qiC+7ObRyeBdeJprehnd2nTLjydUKb5QPt4VylKmJD5K7x/hkkTz/jcll q1sw== 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=C6Pcc0KCAqq6UnYDDdgdeBt1kbXH4HvttEs94ToLTKU=; b=GxoU4VweG5UUlxKntHEkodvnMhRXABXzD0YckGMokoQns9RqMwIs1WH9g/AYHWmneT g7tZpD9CP5fPgkD6v/VAUOpNDtjHCoX/2LJ5a4hAkDUFctoLMQULBt8aElxadPNsfq/P hMcskBkiS4KHOgGTC52+3nlIaRmtavBd1pQzhI/wcZ7QMBUp3+sMQQFaVGjdIjGgdIIf AZ7v3TIymJxdAZjqN4BQrXTDiLDsDmJwUWv751rWs0IDUi55jFY3M17LIl/QQD4E09TT FYbjm23sjaPOEG0YWezhI+y//x7YXpjsyL5Bkw5JysQoMowHd2FYWWCC5uAqDU3i4vnS fi9A== X-Gm-Message-State: AOAM530k5Qrvpa49Pe8IpqQkq17K4nrBk+JNNKbUJ73UrSULU194f+W3 ljD/OjKOfHiMoYxXbBXCZNiRhjNArZXF9rDj7A4= X-Google-Smtp-Source: ABdhPJygcqGQpE4P+85CCBiCBLzq7mgmdy1ks9XHcNICHXdFdGYVlHXB/cFQV9l/NQncP++0NxMItcE6Qgp8da76C4Q= X-Received: by 2002:a17:906:44f:: with SMTP id e15mr15309655eja.161.1590940907872; Sun, 31 May 2020 09:01:47 -0700 (PDT) MIME-Version: 1.0 References: <20200511093554.211493-2-daniel.vetter@ffwll.ch> <20200514201117.465146-1-daniel.vetter@ffwll.ch> In-Reply-To: <20200514201117.465146-1-daniel.vetter@ffwll.ch> From: Rob Clark Date: Sun, 31 May 2020 09:02:11 -0700 Message-ID: Subject: Re: [PATCH] drm/msm: Don't call dma_buf_vunmap without _vmap To: Daniel Vetter X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Vetter , freedreno , Sean Paul , DRI Development , linux-arm-msm Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Thu, May 14, 2020 at 1:11 PM Daniel Vetter wrote: > > I honestly don't exactly understand what's going on here, but the > current code is wrong for sure: It calls dma_buf_vunmap without ever > calling dma_buf_vmap. > > What I'm not sure about is whether the WARN_ON is correct: > - msm imports dma-buf using drm_prime_sg_to_page_addr_arrays. Which is > a pretty neat layering violation of how you shouldn't peek behind > the curtain of the dma-buf exporter, but par for course. Note that > all the nice new helpers don't (and we should probably have a bit a > warning about this in the kerneldoc). > > - but then in the get_vaddr() in msm_gem.c, we seems to happily wrap a > vmap() around any object with ->pages set (so including imported > dma-buf). > > - I'm not seeing any guarantees that userspace can't use an imported > dma-buf for e.g. MSM_SUBMIT_CMD_BUF in a5xx_submit_in_rb, so no > guarantees that an imported dma-buf won't end up with a ->vaddr set. > > But even if that WARN_ON is wrong, cleaning up a vmap() done by msm by > calling dma_buf_vunmap is the wrong thing to do. > > v2: Rob said in review that we do indeed have a gap in get_vaddr() that > needs to be plugged. But the users I've found aren't legit users on > imported dma-buf, so we can just reject that. > > Signed-off-by: Daniel Vetter > Cc: Rob Clark > Cc: Sean Paul > Cc: linux-arm-msm@vger.kernel.org > Cc: freedreno@lists.freedesktop.org Reviewed-by: Rob Clark > --- > drivers/gpu/drm/msm/msm_gem.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c > index 5a6a79fbc9d6..e70abd1cde43 100644 > --- a/drivers/gpu/drm/msm/msm_gem.c > +++ b/drivers/gpu/drm/msm/msm_gem.c > @@ -554,6 +554,9 @@ static void *get_vaddr(struct drm_gem_object *obj, unsigned madv) > struct msm_gem_object *msm_obj = to_msm_bo(obj); > int ret = 0; > > + if (obj->import_attach) > + return ERR_PTR(-ENODEV); > + > mutex_lock(&msm_obj->lock); > > if (WARN_ON(msm_obj->madv > madv)) { > @@ -907,8 +910,7 @@ static void free_object(struct msm_gem_object *msm_obj) > put_iova(obj); > > if (obj->import_attach) { > - if (msm_obj->vaddr) > - dma_buf_vunmap(obj->import_attach->dmabuf, msm_obj->vaddr); > + WARN_ON(msm_obj->vaddr); > > /* Don't drop the pages for imported dmabuf, as they are not > * ours, just free the array we allocated: > -- > 2.26.2 > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel