mm: kmem: fix a NULL pointer dereference in obj_stock_flush_required()
CVE: CVE-2023-53401
Component: kernel
CWE: CWE-362
Severity: Moderate
CVSS v3: 7.2/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Release date: 2023-01-01T00:00:00+00:00

A null pointer dereference exists in the linux kernel such that in obj_stock_flush_required():stock->cached_objcg can be reset between the check and dereference, resulting in damage to the availability of the system.

Statement: A race in the memcg/objcg accounting allowed stock->cached_objcg to change between check and use, leading to a NULL pointer dereference and kernel crash under concurrency. The fix uses READ_ONCE/WRITE_ONCE for all accesses to cached_objcg, eliminating the data race observed by KCSAN. Impact is a local kernel DoS

Remediation:
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

The system must be rebooted for this update to take effect.
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.