CVE-2024-50019

/// Technical description

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

kthread: unpark only parked kthread

Calling into kthread unparking unconditionally is mostly harmless when

the kthread is already unparked. The wake up is then simply ignored

because the target is not in TASK_PARKED state.

However if the kthread is per CPU, the wake up is preceded by a call

to kthread_bind() which expects the task to be inactive and in

TASK_PARKED state, which obviously isn't the case if it is unparked.

As a result, calling kthread_stop() on an unparked per-cpu kthread

triggers such a warning:

WARNING: CPU: 0 PID: 11 at kernel/kthread.c:525 __kthread_bind_mask kernel/kthread.c:525

<TASK>

kthread_stop+0x17a/0x630 kernel/kthread.c:707

destroy_workqueue+0x136/0xc40 kernel/workqueue.c:5810

wg_destruct+0x1e2/0x2e0 drivers/net/wireguard/device.c:257

netdev_run_todo+0xe1a/0x1000 net/core/dev.c:10693

default_device_exit_batch+0xa14/0xa90 net/core/dev.c:11769

ops_exit_list net/core/net_names

/// 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