CVE-2023-52771

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

cxl/port: Fix delete_endpoint() vs parent unregistration race

The CXL subsystem, at cxl_mem ->probe() time, establishes a lineage of

ports (struct cxl_port objects) between an endpoint and the root of a

CXL topology. Each port including the endpoint port is attached to the

cxl_port driver.

Given that setup, it follows that when either any port in that lineage

goes through a cxl_port ->remove() event, or the memdev goes through a

cxl_mem ->remove() event. The hierarchy below the removed port, or the

entire hierarchy if the memdev is removed needs to come down.

The delete_endpoint() callback is careful to check whether it is being

called to tear down the hierarchy, or if it is only being called to

teardown the memdev because an ancestor port is going through

->remove().

That care needs to take the device_lock() of the endpoint's parent.

Which requires 2 bugs to be fixed:

1/ A reference on the parent is needed to pr

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References