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Commit 60b2ed21 authored by Yang Yingliang's avatar Yang Yingliang Committed by Greg Kroah-Hartman
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cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() 



[ Upstream commit 61c80d1c3833e196256fb060382db94f24d3d9a7 ]

If device_register() fails in cxl_register_afu|adapter(), the device
is not added, device_unregister() can not be called in the error path,
otherwise it will cause a null-ptr-deref because of removing not added
device.

As comment of device_register() says, it should use put_device() to give
up the reference in the error path. So split device_unregister() into
device_del() and put_device(), then goes to put dev when register fails.

Fixes: 14baf4d9 ("cxl: Add guest-specific code")
Signed-off-by: default avatarYang Yingliang <yangyingliang@huawei.com>
Acked-by: default avatarAndrew Donnellan <ajd@linux.ibm.com>
Acked-by: default avatarFrederic Barrat <fbarrat@linux.ibm.com>
Link: https://lore.kernel.org/r/20221111145440.2426970-1-yangyingliang@huawei.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 0078dd87

drivers/misc/cxl/guest.c

+14 −10
Original line number Diff line number Diff line
@@ -959,10 +959,10 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n 
	 * if it returns an error!

	 */

	if ((rc = cxl_register_afu(afu)))

		goto err_put1;

		goto err_put_dev;



	if ((rc = cxl_sysfs_afu_add(afu)))

		goto err_put1;

		goto err_del_dev;



	/*

	 * pHyp doesn't expose the programming models supported by the
@@ -978,7 +978,7 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n 
		afu->modes_supported = CXL_MODE_DIRECTED;



	if ((rc = cxl_afu_select_best_mode(afu)))

		goto err_put2;

		goto err_remove_sysfs;



	adapter->afu[afu->slice] = afu;
@@ -998,10 +998,12 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n 


	return 0;



err_put2:

err_remove_sysfs:

	cxl_sysfs_afu_remove(afu);

err_put1:

	device_unregister(&afu->dev);

err_del_dev:

	device_del(&afu->dev);

err_put_dev:

	put_device(&afu->dev);

	free = false;

	guest_release_serr_irq(afu);

err2:
@@ -1135,18 +1137,20 @@ struct cxl *cxl_guest_init_adapter(struct device_node *np, struct platform_devic 
	 * even if it returns an error!

	 */

	if ((rc = cxl_register_adapter(adapter)))

		goto err_put1;

		goto err_put_dev;



	if ((rc = cxl_sysfs_adapter_add(adapter)))

		goto err_put1;

		goto err_del_dev;



	/* release the context lock as the adapter is configured */

	cxl_adapter_context_unlock(adapter);



	return adapter;



err_put1:

	device_unregister(&adapter->dev);

err_del_dev:

	device_del(&adapter->dev);

err_put_dev:

	put_device(&adapter->dev);

	free = false;

	cxl_guest_remove_chardev(adapter);

err1: