CVE-2025-38372

A flaw was found in the Linux kernel's Remote Direct Memory Access (RDMA) subsystem, specifically within the mlx5 driver's implicit On-Demand Paging (ODP) handling. A local user could exploit this vulnerability due to unsafe access to xarray data structures, where __xa_store() and __xa_erase() functions were used without proper locking. This improper handling can lead to a lockdep warning and unsafe Read-Copy Update (RCU) usage, potentially resulting in a denial of service (DoS) for the system.

A moderate-severity flaw was found in the Linux kernel's mlx5 RDMA driver within its implicit On-Demand Paging (ODP) handling. The affected code used the __xa_store() and __xa_erase() xarray operations without holding the proper lock, which constitutes unsafe RCU usage and triggers a lockdep warning. A local user with the ability to trigger mlx5 ODP page-fault handling could potentially exploit this flaw to cause a denial of service. Red Hat rated this flaw Moderate (CVSS 3.1 score 5.5, AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) because only availability is affected; the higher upstream CVE.org score of 7.8 additionally assumes confidentiality and integrity impact, which the available evidence does not support. Red Hat Enterprise Linux 9 kernel and kernel-rt are affected; the vulnerable code is not present in Red Hat Enterprise Linux 6, 7, 8, and 10 or in Red Hat In-Vehicle OS, so those products are not affected. For the affected RHEL 9 streams the fix has been deferred given the limited practical impact, which is a lockdep warning and potential local denial of service restricted to a specific RDMA/ODP use case; the residual risk is that a local user on a system using mlx5 RDMA with implicit ODP could trigger a kernel-level availability impact.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.