In the Linux kernel RDMA/erdma subsystem, a lock ordering issue triggers a deadlock between interrupt lookups and create-path updates to the QP and CQ tables, so when an interrupt occurs while the create-path holds a plain xa_lock, the lookup spins forever, preventing progress and potentially freezing RDMA operations. The flaw, a concurrency problem, can cause the kernel to become unresponsive for RDMA traffic, effectively denying service to affected applications.

All Linux kernel versions that implement the RDMA/erdma subsystem with the older xa_lock mechanism for QP and CQ tables are affected. The issue is mitigated by applying the patch that replaces the plain xa_lock with IRQ‑safe XArray helpers and initializes the arrays with XA_FLAGS_LOCK_IRQ. Exact version ranges are not specified in the provided data.

The EPSS score of < 1% indicates a very low exploitation probability. The likely attack vector is an attacker triggering RDMA traffic or having privileged access to the system, as this is required for the deadlock to occur; this information is inferred from the description. The vulnerability is not listed in the CISA KEV catalog, so no publicly known exploitation is documented. Exploitation would require unusual RDMA activity or elevated privileges, limiting the attack surface. The risk remains moderate because a deadlock can cripple RDMA functionalities, but the exploitation likelihood is considered low under typical scenarios. The CVSS score of 5.5 denotes a medium severity risk.