This is a note to let you know that I've just added the patch titled
cxl: fix possible null-ptr-deref in cxl_guest_init_afu|adapter()
to the 4.14-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_guest_init_af.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d0cf622067b8d81f12fb6492501887a8e88e737b
Author: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Date: Fri Nov 11 22:54:39 2022 +0800
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: 14baf4d9c739 ("cxl: Add guest-specific code")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Acked-by: Andrew Donnellan <ajd@xxxxxxxxxxxxx>
Acked-by: Frederic Barrat <fbarrat@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221111145440.2426970-1-yangyingliang@xxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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:
