[PATCH v3 02/18] media: ipu-bridge: Do not use on stack memory for software_node.name field

Hans de Goede
2023-07-05T21:31:55Z

Commit 567f97bd381f ("media: ipu3-cio2: support multiple sensors and VCMs
with same HID") introduced an on stack vcm_name and then uses this for
the name field of the software_node struct used for the vcm.

But the software_node struct is much longer lived then the current
stack-frame, so this is no good.

Instead extend the ipu_node_names struct with an extra field to store
the vcm software_node name and use that.

Note this also changes the length of the allocated buffer from
ACPI_ID_LEN + 4 to 16. the name is filled with "<ipu_vcm_types[x]>-%u"
where ipu_vcm_types[x] is not an ACPI_ID. The maximum length of
the strings in the ipu_vcm_types[] array is 11 + 5 bytes for "-255\0"
means 16 bytes are needed in the worst case scenario.

Fixes: 567f97bd381f ("media: ipu3-cio2: support multiple sensors and VCMs with same HID")
Cc: Bingbu Cao <bingbu.cao@intel.com>
Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Daniel Scally <dan.scally@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/media/pci/intel/ipu-bridge.c | 7 +++----
drivers/media/pci/intel/ipu-bridge.h | 1 +
2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/media/pci/intel/ipu-bridge.c b/drivers/media/pci/intel/ipu-bridge.c
index f0927f80184d..ef6c6cb7b51b 100644
--- a/drivers/media/pci/intel/ipu-bridge.c
+++ b/drivers/media/pci/intel/ipu-bridge.c
@@ -220,7 +220,6 @@ static void ipu_bridge_create_connection_swnodes(struct ipu_bridge *bridge,
struct ipu_sensor *sensor)
{
struct software_node *nodes = sensor->swnodes;
- char vcm_name[ACPI_ID_LEN + 4];

ipu_bridge_init_swnode_names(sensor);

@@ -240,10 +239,10 @@ static void ipu_bridge_create_connection_swnodes(struct ipu_bridge *bridge,
sensor->ipu_properties);
if (sensor->ssdb.vcmtype) {
/* append ssdb.link to distinguish VCM nodes with same HID */
- snprintf(vcm_name, sizeof(vcm_name), "%s-%u",
- ipu_vcm_types[sensor->ssdb.vcmtype - 1],
+ snprintf(sensor->node_names.vcm, sizeof(sensor->node_names.vcm),
+ "%s-%u", ipu_vcm_types[sensor->ssdb.vcmtype - 1],
sensor->ssdb.link);
- nodes[SWNODE_VCM] = NODE_VCM(vcm_name);
+ nodes[SWNODE_VCM] = NODE_VCM(sensor->node_names.vcm);
}

ipu_bridge_init_swnode_group(sensor);
diff --git a/drivers/media/pci/intel/ipu-bridge.h b/drivers/media/pci/intel/ipu-bridge.h
index 8cb733c03e2f..6cce712a0f34 100644
--- a/drivers/media/pci/intel/ipu-bridge.h
+++ b/drivers/media/pci/intel/ipu-bridge.h
@@ -103,6 +103,7 @@ struct ipu_node_names {
char port[7];
char endpoint[11];
char remote_port[7];
+ char vcm[16];
};

struct ipu_sensor_config {
--
2.41.0