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cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter() 

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: 14baf4d9c7 ("cxl: Add guest-specific code")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Link: https://lore.kernel.org/r/20221111145440.2426970-1-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yang Yingliang 2022-11-11 22:54:39 +08:00 committed by Greg Kroah-Hartman
parent fa1ba41c17
commit 61c80d1c38
1 changed files with 14 additions and 10 deletions
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24
drivers/misc/cxl/guest.c
View File

@ -965,10 +965,10 @@ 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
@ -984,7 +984,7 @@ 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;
@ -1004,10 +1004,12 @@ 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:
@ -1141,18 +1143,20 @@ 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: