This is a note to let you know that I've just added the patch titled cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter() to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: cxl-fix-possible-null-ptr-deref-in-cxl_pci_init_afu-.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 0c4d791ad96eabb905b5164a0f2711e74fc37d5b Author: Yang Yingliang <yangyingliang@xxxxxxxxxx> Date: Fri Nov 11 22:54:40 2022 +0800 cxl: fix possible null-ptr-deref in cxl_pci_init_afu|adapter() [ 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@xxxxxxxxxx> Acked-by: Frederic Barrat <fbarrat@xxxxxxxxxxxxx> Acked-by: Andrew Donnellan <ajd@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20221111145440.2426970-2-yangyingliang@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> 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: