CVE-2025-40347

Technical Description

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

net: enetc: fix the deadlock of enetc_mdio_lock

After applying the workaround for err050089, the LS1028A platform

experiences RCU stalls on RT kernel. This issue is caused by the

recursive acquisition of the read lock enetc_mdio_lock. Here list some

of the call stacks identified under the enetc_poll path that may lead to

a deadlock:

enetc_poll

-> enetc_lock_mdio

-> enetc_clean_rx_ring OR napi_complete_done

-> napi_gro_receive

-> enetc_start_xmit

-> enetc_lock_mdio

-> enetc_map_tx_buffs

-> enetc_unlock_mdio

-> enetc_unlock_mdio

After enetc_poll acquires the read lock, a higher-priority writer attempts

to acquire the lock, causing preemption. The writer detects that a

read lock is already held and is scheduled out. However, readers under

enetc_poll cannot acquire the read lock again because a writer is already

waiting, leading to a thread hang.

Currently, the deadl

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