[PATCH 6.1 0721/1146] cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter()

Greg Kroah-Hartman
2022-12-28T16:29:07Z

From: Yang Yingliang <yangyingliang@huawei.com>

[ Upstream commit 02cd3032b154fa02fdf90e7467abaeed889330b2 ]

If device_register() fails in cxl_pci_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: f204e0b8cedd ("cxl: Driver code for powernv PCIe based cards for userspace access")
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
Link: https://lore.kernel.org/r/20221111145440.2426970-2-yangyingliang@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/misc/cxl/pci.c | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
index 3de0aea62ade..6d495d641c95 100644
--- a/drivers/misc/cxl/pci.c
+++ b/drivers/misc/cxl/pci.c
@@ -1164,10 +1164,10 @@ static int pci_init_afu(struct cxl *adapter, int slice, struct pci_dev *dev)
* 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;

adapter->afu[afu->slice] = afu;

@@ -1176,10 +1176,12 @@ static int pci_init_afu(struct cxl *adapter, int slice, struct pci_dev *dev)

return 0;

-err_put1:
+err_del_dev:
+ device_del(&afu->dev);
+err_put_dev:
pci_deconfigure_afu(afu);
cxl_debugfs_afu_remove(afu);
- device_unregister(&afu->dev);
+ put_device(&afu->dev);
return rc;

err_free_native:
@@ -1667,23 +1669,25 @@ static struct cxl *cxl_pci_init_adapter(struct pci_dev *dev)
* 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 adapter is configured */
cxl_adapter_context_unlock(adapter);

return adapter;

-err_put1:
+err_del_dev:
+ device_del(&adapter->dev);
+err_put_dev:
/* This should mirror cxl_remove_adapter, except without the
* sysfs parts
*/
cxl_debugfs_adapter_remove(adapter);
cxl_deconfigure_adapter(adapter);
- device_unregister(&adapter->dev);
+ put_device(&adapter->dev);
return ERR_PTR(rc);

err_release:
--
2.35.1