Hi Biju,
On Wed, Nov 6, 2024 at 7:49 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> The host_node pointer assigned and freed in adv7533_parse_dt()
> and later adv7533_attach_dsi() uses the same. Fix this issue
> by freeing the host_node in adv7533_attach_dsi() instead of
> adv7533_parse_dt().
>
> Fixes: 1e4d58cd7f88 ("drm/bridge: adv7533: Create a MIPI DSI device")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> Changes in v3:
> - Replace __free construct with readable of_node_put().
> Changes in v2:
> - Added the tag "Cc: stable@xxxxxxxxxxxxxxx" in the sign-off area.
> - Dropped Archit Taneja invalid Mail address
Thanks for the update!
> --- a/drivers/gpu/drm/bridge/adv7511/adv7533.c
> +++ b/drivers/gpu/drm/bridge/adv7511/adv7533.c
> @@ -143,6 +143,7 @@ int adv7533_attach_dsi(struct adv7511 *adv)
> };
>
> host = of_find_mipi_dsi_host_by_node(adv->host_node);
> + of_node_put(adv->host_node);
This still looks fragile to me, as afterwards a pointer to a freed
node is left in struct adv7511.host_node. It would be safer to also
clear adv->host_node here.
However, taking a look from a distance, the code looks like:
static int adv7511_probe(struct i2c_client *i2c)
{
...
adv7533_parse_dt(dev->of_node, adv7511);
...
if (adv7511->info->has_dsi)
ret = adv7533_attach_dsi(adv7511);
...
}
The only reason adv7511.host_node exists is to pass it from
adv7533_parse_dt() to adv7533_attach_dsi().
So what about making this explicit?
1. Let adv7533_parse_dt() return the host_node or an error pointer,
2. Pass the host_node as a parameter to adv7533_attach_dsi(),
3. Call of_node_put() in adv7511_probe() after use.
> if (!host)
> return dev_err_probe(dev, -EPROBE_DEFER,
> "failed to find dsi host\n");
> @@ -181,8 +182,6 @@ int adv7533_parse_dt(struct device_node *np, struct adv7511 *adv)
> if (!adv->host_node)
> return -ENODEV;
>
> - of_node_put(adv->host_node);
> -
> adv->use_timing_gen = !of_property_read_bool(np,
> "adi,disable-timing-generator");
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
