Re: [PATCH] of: overlay: add_changeset_property() memory leak

Frank Rowand
2019-11-21T19:20:25Z

Hi Vincent,

On 11/21/19 1:16 PM, frowand.list@gmail.com wrote:
> From: Frank Rowand <frank.rowand@sony.com>
>
> No changeset entries are created for #address-cells and #size-cells
> properties, but the duplicated properties are never freed. This
> results in a memory leak which is detected by kmemleak:
>
> unreferenced object 0x85887180 (size 64):
> backtrace:
> kmem_cache_alloc_trace+0x1fb/0x1fc
> __of_prop_dup+0x25/0x7c
> add_changeset_property+0x17f/0x370
> build_changeset_next_level+0x29/0x20c
> of_overlay_fdt_apply+0x32b/0x6b4
> ...
>
> Fixes: 6f75118800acf77f8 ("of: overlay: validate overlay properties #address-cells and #size-cells")
> Reported-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
> Signed-off-by: Frank Rowand <frank.rowand@sony.com>
> ---
> drivers/of/overlay.c | 37 ++++++++++++++++++++-----------------
> 1 file changed, 20 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c
> index c423e94baf0f..9617b7df7c4d 100644
> --- a/drivers/of/overlay.c
> +++ b/drivers/of/overlay.c
> @@ -305,7 +305,6 @@ 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 (target->in_livetree)
> if (!of_prop_cmp(overlay_prop->name, "name") ||
> @@ -318,6 +317,25 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
> else
> prop = NULL;
>
> + if (prop) {
> + if (!of_prop_cmp(prop->name, "#address-cells")) {
> + if (!of_prop_val_eq(prop, overlay_prop)) {
> + pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
> + target->np);
> + ret = -EINVAL;
> + }
> + return ret;
> +
> + } else if (!of_prop_cmp(prop->name, "#size-cells")) {
> + if (!of_prop_val_eq(prop, overlay_prop)) {
> + pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
> + target->np);
> + ret = -EINVAL;
> + }
> + return ret;
> + }
> + }
> +
> if (is_symbols_prop) {
> if (prop)
> return -EINVAL;
> @@ -330,33 +348,18 @@ static int add_changeset_property(struct overlay_changeset *ovcs,
> return -ENOMEM;
>
> if (!prop) {
> - check_for_non_overlay_node = true;
> if (!target->in_livetree) {
> new_prop->next = target->np->deadprops;
> target->np->deadprops = new_prop;
> }
> ret = of_changeset_add_property(&ovcs->cset, target->np,
> new_prop);
> - } else if (!of_prop_cmp(prop->name, "#address-cells")) {
> - if (!of_prop_val_eq(prop, new_prop)) {
> - pr_err("ERROR: changing value of #address-cells is not allowed in %pOF\n",
> - target->np);
> - ret = -EINVAL;
> - }
> - } else if (!of_prop_cmp(prop->name, "#size-cells")) {
> - if (!of_prop_val_eq(prop, new_prop)) {
> - pr_err("ERROR: changing value of #size-cells is not allowed in %pOF\n",
> - target->np);
> - ret = -EINVAL;
> - }
> } 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))
> + if (!of_node_check_flag(target->np, OF_OVERLAY))
> pr_err("WARNING: memory leak will occur if overlay removed, property: %pOF/%s\n",
> target->np, new_prop->name);
>
>

Can you please check whether this patch fixes the memleak that you
found and fixed in "[PATCH 1/2] of: overlay: fix properties memory leak"?

Thanks,

Frank