From: Yang Yingliang yangyingliang@huawei.com
[ 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: 14baf4d9c739 ("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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/misc/cxl/guest.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c index de2ce5539545..47a52e73e9de 100644 --- a/drivers/misc/cxl/guest.c +++ b/drivers/misc/cxl/guest.c @@ -971,10 +971,10 @@ 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 @@ -990,7 +990,7 @@ 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;
@@ -1010,10 +1010,12 @@ 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: @@ -1147,18 +1149,20 @@ 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: