In the Linux kernel, the following vulnerability has been resolved:
fs/resctrl: Fix UAF from worker threads when domains are removed
The mbm_handle_overflow() and cqm_handle_limbo() workers read event counters
and may sleep while doing so. They are scheduled via delayed_work embedded in
struct rdt_l3_mon_domain. Architecture allocates and frees these domains from
CPU hotplug callbacks under cpus_write_lock(), and the workers acquire
cpus_read_lock() to keep the domain alive across their access.
A use-after-free can occur when a worker is blocked waiting for
cpus_read_lock() while the hotplug core holds cpus_write_lock(): the
architecture frees the rdt_l3_mon_domain that contains the worker's
work_struct. When the worker unblocks, the container_of() it performs on the
embedded work pointer dereferences freed memory.
Drop cpus_read_lock() from the workers and instead drain pending and in-flight
work synchronously before the architecture can free the domain. Since
architecture offlines the domain under cpus_write_lock() after it has been
unlinked from the RCU list and a grace period has elapsed, no new work can be
scheduled. The cancel only needs to wait out existing work. Drop
rdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that
a worker waiting on the mutex can complete before re-pinning the work on
a different CPU.
When offlining a CPU the architecture may iterate over resources in any order.
For example, the MBA control domain may be offlined before or after
a corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers
no matter what order the architecture offlines the domains.
CVSS
No CVSS.
References
Configurations
No configuration.
History
17 Sep 2026, 17:18
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-09-17 17:18
Updated : 2026-09-17 17:18
NVD link : CVE-2026-93099
Mitre link : CVE-2026-93099
CVE.ORG link : CVE-2026-93099
JSON object : View
Products Affected
No product.
CWE
No CWE.