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Message-ID: <b6ee53f7e02cc3ea52713ae82402e97d7050cb3e.camel@perches.com>
Date: Sun, 14 Oct 2018 18:06:40 -0700
From: Joe Perches <joe@...ches.com>
To: frowand.list@...il.com, Rob Herring <robh+dt@...nel.org>,
Pantelis Antoniou <pantelis.antoniou@...sulko.com>,
Michael Ellerman <mpe@...erman.id.au>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Alan Tull <atull@...nel.org>, Moritz Fischer <mdf@...nel.org>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
devicetree@...r.kernel.org, linux-fpga@...r.kernel.org
Subject: Re: [PATCH v3 13/18] of: overlay: check prevents multiple fragments
touching same property
On Sun, 2018-10-14 at 17:24 -0700, frowand.list@...il.com wrote:
> From: Frank Rowand <frank.rowand@...y.com>
>
> Add test case of two fragments updating the same property. After
> adding the test case, the system hangs at end of boot, after
> after slub stack dumps from kfree() in crypto modprobe code.
[]
> -static int check_changeset_dup_add_node(struct overlay_changeset *ovcs)
> +static int changeset_dup_entry_check(struct overlay_changeset *ovcs)
> {
> - struct of_changeset_entry *ce_1, *ce_2;
> - char *fn_1, *fn_2;
> - int name_match;
> + struct of_changeset_entry *ce_1;
> + int dup_entry = 0;
>
> list_for_each_entry(ce_1, &ovcs->cset.entries, node) {
> -
> - if (ce_1->action == OF_RECONFIG_ATTACH_NODE ||
> - ce_1->action == OF_RECONFIG_DETACH_NODE) {
> -
> - ce_2 = ce_1;
> - list_for_each_entry_continue(ce_2, &ovcs->cset.entries, node) {
> - if (ce_2->action == OF_RECONFIG_ATTACH_NODE ||
> - ce_2->action == OF_RECONFIG_DETACH_NODE) {
> - /* inexpensive name compare */
> - if (!of_node_cmp(ce_1->np->full_name,
> - ce_2->np->full_name)) {
> - /* expensive full path name compare */
> - fn_1 = kasprintf(GFP_KERNEL, "%pOF", ce_1->np);
> - fn_2 = kasprintf(GFP_KERNEL, "%pOF", ce_2->np);
> - name_match = !strcmp(fn_1, fn_2);
> - kfree(fn_1);
> - kfree(fn_2);
> - if (name_match) {
> - pr_err("ERROR: multiple overlay fragments add and/or delete node %pOF\n",
> - ce_1->np);
> - return -EINVAL;
> - }
> - }
> - }
> - }
> - }
> + dup_entry |= find_dup_cset_node_entry(ovcs, ce_1);
> + dup_entry |= find_dup_cset_prop(ovcs, ce_1);
I think this is worse performance than before.
This now walks all entries when before it would
return -EINVAL directly when it found a match.
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