[PATCH 03/51] drm: add managed resources tied to drm_device

[Dan Carpenter]

Hi Daniel,

I love your patch! Perhaps something to improve:

url:    https://github.com/0day-ci/linux/commits/Daniel-Vetter/drm_device-managed-resources-v4/20200303-071023
base:   git://anongit.freedesktop.org/drm/drm-tip drm-tip

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp at intel.com>
Reported-by: Dan Carpenter <dan.carpenter at oracle.com>

smatch warnings:
drivers/gpu/drm/drm_drv.c:843 drm_dev_release() error: dereferencing freed memory 'dev'

# https://github.com/0day-ci/linux/commit/5aba700d4c32ae5722a9931c959b13a6217a86e2
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 5aba700d4c32ae5722a9931c959b13a6217a86e2
vim +/dev +843 drivers/gpu/drm/drm_drv.c

099d1c290e2ebc drivers/gpu/drm/drm_stub.c David Herrmann 2014-01-29  826  static void drm_dev_release(struct kref *ref)
0dc8fe5985e01f drivers/gpu/drm/drm_stub.c David Herrmann 2013-10-02  827  {
099d1c290e2ebc drivers/gpu/drm/drm_stub.c David Herrmann 2014-01-29  828  	struct drm_device *dev = container_of(ref, struct drm_device, ref);
8f6599da8e772f drivers/gpu/drm/drm_stub.c David Herrmann 2013-10-20  829  
f30c92576af4bb drivers/gpu/drm/drm_drv.c  Chris Wilson   2017-02-02  830  	if (dev->driver->release) {
f30c92576af4bb drivers/gpu/drm/drm_drv.c  Chris Wilson   2017-02-02  831  		dev->driver->release(dev);
f30c92576af4bb drivers/gpu/drm/drm_drv.c  Chris Wilson   2017-02-02  832  	} else {
f30c92576af4bb drivers/gpu/drm/drm_drv.c  Chris Wilson   2017-02-02  833  		drm_dev_fini(dev);
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  834  	}
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  835  
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  836  	drm_managed_release(dev);
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  837  
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  838  	if (!dev->driver->release && !dev->managed.final_kfree) {
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  839  		WARN_ON(!list_empty(&dev->managed.resources));
0dc8fe5985e01f drivers/gpu/drm/drm_stub.c David Herrmann 2013-10-02  840  		kfree(dev);
                                                                                        ^^^^^^^^^^
Free

0dc8fe5985e01f drivers/gpu/drm/drm_stub.c David Herrmann 2013-10-02  841  	}
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  842  
5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02 @843  	if (dev->managed.final_kfree)
                                                                                    ^^^^^
Dereference

5aba700d4c32ae drivers/gpu/drm/drm_drv.c  Daniel Vetter  2020-03-02  844  		kfree(dev->managed.final_kfree);
f30c92576af4bb drivers/gpu/drm/drm_drv.c  Chris Wilson   2017-02-02  845  }

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0-DAY CI Kernel Test Service, Intel Corporation
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