[bug report] drm: Begin an API for in-kernel clients

[Dan Carpenter]

Hello Noralf Trønnes,

The patch c76f0f7cb546: "drm: Begin an API for in-kernel clients"
from Jul 3, 2018, leads to the following static checker warning:

	drivers/gpu/drm/drm_client.c:289 drm_client_buffer_create()
	error: double free of 'buffer'

drivers/gpu/drm/drm_client.c
   268          /*
   269           * FIXME: The dependency on GEM here isn't required, we could
   270           * convert the driver handle to a dma-buf instead and use the
   271           * backend-agnostic dma-buf vmap support instead. This would
   272           * require that the handle2fd prime ioctl is reworked to pull the
   273           * fd_install step out of the driver backend hooks, to make that
   274           * final step optional for internal users.
   275           */
   276          vaddr = dev->driver->gem_prime_vmap(obj);
   277          if (!vaddr) {
   278                  ret = -ENOMEM;
   279                  goto err_delete;
   280          }
   281  
   282          buffer->vaddr = vaddr;
   283  
   284          return buffer;
   285  
   286  err_delete:
   287          drm_client_buffer_delete(buffer);
                                         ^^^^^^
Freed here

   288  err_free:
   289          kfree(buffer);
                      ^^^^^^
Double free

   290  
   291          return ERR_PTR(ret);
   292  }
   293  

regards,
dan carpenter