[PATCH next] drm/vkms: Fix use after frees on error paths

[Dan Carpenter]

These error paths free a pointer and then dereference it on the next line
to get the error code.  Save the error code first and then free the
memory.

Fixes: 3e4d5b30d2b2 ("drm/vkms: Allow to configure multiple CRTCs via configfs")
Fixes: 2f1734ba271b ("drm/vkms: Allow to configure multiple planes via 
configfs")
Fixes: 67d8cf92e13e ("drm/vkms: Allow to configure multiple encoders via 
configfs")
Fixes: 272acbca96a3 ("drm/vkms: Allow to configure multiple connectors via 
configfs")
Fixes: 13fc9b9745cc ("drm/vkms: Add and remove VKMS instances via configfs")
Signed-off-by: Dan Carpenter <dan.carpen...@linaro.org>
---
 drivers/gpu/drm/vkms/vkms_configfs.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/vkms/vkms_configfs.c 
b/drivers/gpu/drm/vkms/vkms_configfs.c
index 07ab794e1052..506666e21c91 100644
--- a/drivers/gpu/drm/vkms/vkms_configfs.c
+++ b/drivers/gpu/drm/vkms/vkms_configfs.c
@@ -204,6 +204,7 @@ static struct config_group *make_crtc_group(struct 
config_group *group,
 {
        struct vkms_configfs_device *dev;
        struct vkms_configfs_crtc *crtc;
+       int ret;
 
        dev = child_group_to_vkms_configfs_device(group);
 
@@ -219,8 +220,9 @@ static struct config_group *make_crtc_group(struct 
config_group *group,
 
                crtc->config = vkms_config_create_crtc(dev->config);
                if (IS_ERR(crtc->config)) {
+                       ret = PTR_ERR(crtc->config);
                        kfree(crtc);
-                       return ERR_CAST(crtc->config);
+                       return ERR_PTR(ret);
                }
 
                config_group_init_type_name(&crtc->group, name, 
&crtc_item_type);
@@ -358,6 +360,7 @@ static struct config_group *make_plane_group(struct 
config_group *group,
 {
        struct vkms_configfs_device *dev;
        struct vkms_configfs_plane *plane;
+       int ret;
 
        dev = child_group_to_vkms_configfs_device(group);
 
@@ -373,8 +376,9 @@ static struct config_group *make_plane_group(struct 
config_group *group,
 
                plane->config = vkms_config_create_plane(dev->config);
                if (IS_ERR(plane->config)) {
+                       ret = PTR_ERR(plane->config);
                        kfree(plane);
-                       return ERR_CAST(plane->config);
+                       return ERR_PTR(ret);
                }
 
                config_group_init_type_name(&plane->group, name, 
&plane_item_type);
@@ -472,6 +476,7 @@ static struct config_group *make_encoder_group(struct 
config_group *group,
 {
        struct vkms_configfs_device *dev;
        struct vkms_configfs_encoder *encoder;
+       int ret;
 
        dev = child_group_to_vkms_configfs_device(group);
 
@@ -487,8 +492,9 @@ static struct config_group *make_encoder_group(struct 
config_group *group,
 
                encoder->config = vkms_config_create_encoder(dev->config);
                if (IS_ERR(encoder->config)) {
+                       ret = PTR_ERR(encoder->config);
                        kfree(encoder);
-                       return ERR_CAST(encoder->config);
+                       return ERR_PTR(ret);
                }
 
                config_group_init_type_name(&encoder->group, name,
@@ -637,6 +643,7 @@ static struct config_group *make_connector_group(struct 
config_group *group,
 {
        struct vkms_configfs_device *dev;
        struct vkms_configfs_connector *connector;
+       int ret;
 
        dev = child_group_to_vkms_configfs_device(group);
 
@@ -652,8 +659,9 @@ static struct config_group *make_connector_group(struct 
config_group *group,
 
                connector->config = vkms_config_create_connector(dev->config);
                if (IS_ERR(connector->config)) {
+                       ret = PTR_ERR(connector->config);
                        kfree(connector);
-                       return ERR_CAST(connector->config);
+                       return ERR_PTR(ret);
                }
 
                config_group_init_type_name(&connector->group, name,
@@ -756,6 +764,7 @@ static struct config_group *make_device_group(struct 
config_group *group,
                                              const char *name)
 {
        struct vkms_configfs_device *dev;
+       int ret;
 
        if (strcmp(name, DEFAULT_DEVICE_NAME) == 0)
                return ERR_PTR(-EINVAL);
@@ -766,8 +775,9 @@ static struct config_group *make_device_group(struct 
config_group *group,
 
        dev->config = vkms_config_create(name);
        if (IS_ERR(dev->config)) {
+               ret = PTR_ERR(dev->config);
                kfree(dev);
-               return ERR_CAST(dev->config);
+               return ERR_PTR(ret);
        }
 
        config_group_init_type_name(&dev->group, name, &device_item_type);
-- 
2.51.0