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[209.132.180.67]) by mx.google.com with ESMTP id z67-v6si4676776pfz.5.2018.10.15.12.03.23; Mon, 15 Oct 2018 12:03:39 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=GRo3ovJI; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726970AbeJPCs0 (ORCPT + 99 others); Mon, 15 Oct 2018 22:48:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:50312 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726654AbeJPCs0 (ORCPT ); Mon, 15 Oct 2018 22:48:26 -0400 Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com [209.85.208.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A06DA2145D; Mon, 15 Oct 2018 19:01:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1539630113; bh=HZTikMm58VpHYYjCoXzcMq7g8Vxcno1d4W4fqZ5OWo0=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=GRo3ovJIp2jdatGOFaTllO16wLgJAhJFK5inzMHOGCWcQvhHqrDR+cmfn0V4HSbzy rWdu6kTxFE0NR5gKkjxOmhToSKsUNjCEzaqzBAJmt94STfdU7yiQVnp+Ah7g4BrlWL hLZZEJaDvNTzsmfo8qxRSu2coSUUw/uwPNry71Cs= Received: by mail-ed1-f41.google.com with SMTP id c26-v6so18905077edt.3; Mon, 15 Oct 2018 12:01:53 -0700 (PDT) X-Gm-Message-State: ABuFfog4GAt4DoSxWFWXA63CgU0GUhHgFSqPmReT/lKsCBPcWYROh9ef 5D0NqlYiVCEGZl8RUgq9t2/f01G2tPHrBjgB8OA= X-Received: by 2002:a17:906:7384:: with SMTP id f4-v6mr20302835ejl.8.1539630111956; Mon, 15 Oct 2018 12:01:51 -0700 (PDT) MIME-Version: 1.0 References: <1539563070-12969-1-git-send-email-frowand.list@gmail.com> <1539563070-12969-10-git-send-email-frowand.list@gmail.com> In-Reply-To: <1539563070-12969-10-git-send-email-frowand.list@gmail.com> From: Alan Tull Date: Mon, 15 Oct 2018 14:01:15 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v3 09/18] of: overlay: validate overlay properties #address-cells and #size-cells To: Frank Rowand Cc: Rob Herring , Pantelis Antoniou , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , Moritz Fischer , linux-kernel , linuxppc-dev , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , linux-fpga@vger.kernel.org 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 On Sun, Oct 14, 2018 at 7:26 PM wrote: > > From: Frank Rowand > > If overlay properties #address-cells or #size-cells are already in > the live devicetree for any given node, then the values in the > overlay must match the values in the live tree. > > If the properties are already in the live tree then there is no > need to create a changeset entry to add them since they must > have the same value. This reduces the memory used by the > changeset and eliminates a possible memory leak. This is > verified by 12 fewer warnings during the devicetree unittest, > as the possible memory leak warnings about #address-cells and > > Signed-off-by: Frank Rowand > --- > drivers/of/overlay.c | 38 +++++++++++++++++++++++++++++++++++--- > 1 file changed, 35 insertions(+), 3 deletions(-) > > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c > index 272a0d1a5e18..ee66651db553 100644 > --- a/drivers/of/overlay.c > +++ b/drivers/of/overlay.c > @@ -287,7 +287,12 @@ static struct property *dup_and_fixup_symbol_prop( > * @target may be either in the live devicetree or in a new subtree that > * is contained in the changeset. > * > - * Some special properties are not updated (no error returned). > + * Some special properties are not added or updated (no error returned): > + * "name", "phandle", "linux,phandle". > + * > + * Properties "#address-cells" and "#size-cells" are not updated if they > + * are already in the live tree, but if present in the live tree, the values > + * in the overlay must match the values in the live tree. > * > * Update of property in symbols node is not allowed. > * > @@ -300,6 +305,7 @@ static int add_changeset_property(struct overlay_changeset *ovcs, > { > struct property *new_prop = NULL, *prop; > int ret = 0; > + bool check_for_non_overlay_node = false; > > if (!of_prop_cmp(overlay_prop->name, "name") || > !of_prop_cmp(overlay_prop->name, "phandle") || > @@ -322,13 +328,39 @@ static int add_changeset_property(struct overlay_changeset *ovcs, > if (!new_prop) > return -ENOMEM; > > - if (!prop) > + if (!prop) { > + > + check_for_non_overlay_node = true; > ret = of_changeset_add_property(&ovcs->cset, target->np, > new_prop); > - else > + > + } else if (!of_prop_cmp(prop->name, "#address-cells")) { > + Hi Frank, If we get these ERROR messages, I suggest that this function should return an error so the overlay will be rejected. > + if (prop->length != 4 || new_prop->length != 4 || > + *(u32 *)prop->value != *(u32 *)new_prop->value) *(u32 *)prop->value != *(u32 *)new_prop->value) { > + pr_err("ERROR: overlay and/or live tree #address-cells invalid in node %pOF\n", > + target->np); ret = -EINVAL; } Otherwise there is an ERROR message, but it continues trying to apply the invalid overlay anyway and I get an oops. By adding the ret = -EINVAL, the overlay gets rejected and the oops is avoided. > + > + } else if (!of_prop_cmp(prop->name, "#size-cells")) { > + > + if (prop->length != 4 || new_prop->length != 4 || > + *(u32 *)prop->value != *(u32 *)new_prop->value) > + pr_err("ERROR: overlay and/or live tree #size-cells invalid in node %pOF\n", > + target->np); Add the ret = -EINVAL here also. This give me the following (if my overlay changes #address-cells): [ 21.167551] OF: overlay: ERROR: overlay and/or live tree #address-cells invalid in node /soc/base_fpga_region [ 21.177442] OF: overlay: add_changeset_property ret=-22 [ 21.182656] create_overlay: Failed to create overlay (err=-22) Also, I wonder if the ERROR message could be more direct. Currently it says the #address-cells property is invalid but that doesn't say anything about why it's invalid. How about something like: OF: overlay: ERROR: changing #address-cells not allowed (/soc/base_fpga_region) The 'OF: overlay' part still makes it clear it's overlay related. The rest of it makes it clear *why* it's invalid. This ERROR will be a surprise for people who have been using overlays, so that could be helpful to light the way a bit. Alan > + > + } else { > + > + check_for_non_overlay_node = true; > ret = of_changeset_update_property(&ovcs->cset, target->np, > new_prop); > > + } > + > + if (check_for_non_overlay_node && > + !of_node_check_flag(target->np, OF_OVERLAY)) > + pr_err("WARNING: %s(), memory leak will occur if overlay removed. Property: %pOF/%s\n", > + __func__, target->np, new_prop->name); > + > if (ret) { > kfree(new_prop->name); > kfree(new_prop->value); > -- > Frank Rowand >