CVE-2024-26873 is a vulnerability identified in the Linux kernel specifically affecting the hisi_sas driver, which manages SAS (Serial Attached SCSI) devices on hardware using Huawei's HiSilicon SAS controllers. The issue arises from a deadlock condition triggered when a disabling PHY command is issued to a device, causing it to go offline. Concurrently, if a 2-bit ECC (Error Correcting Code) error occurs, the kernel's workqueue threads responsible for handling SAS device aborts and resets become blocked indefinitely. The root cause is a circular dependency involving the acquisition of the hisi_hba semaphore and the triggering of an automatic dump process. When the device goes offline, the driver obtains the hisi_hba semaphore and sends an ABORT_DEV command to the device. However, due to the ECC error, the internal abort times out and attempts to trigger an automatic dump. Since the semaphore is already held, the dump cannot proceed, preventing the controller reset and causing the kernel worker threads to hang. This results in hung tasks that block for more than 120 seconds, as evidenced by kernel log messages. The deadlock impacts the availability of the affected SAS devices and potentially the entire system relying on these storage controllers. Although no known exploits are reported in the wild, the vulnerability can cause system instability or denial of service on affected Linux systems using the hisi_sas driver. The affected versions are specific Linux kernel commits identified by their hashes, indicating that the issue is present in recent kernel versions prior to the patch. No CVSS score has been assigned yet, but the technical details and kernel logs provide insight into the severity and impact of the flaw.

For European organizations, especially those operating data centers, cloud infrastructure, or enterprise storage solutions running Linux on hardware with HiSilicon SAS controllers, this vulnerability poses a risk of system hangs and denial of service. The deadlock can cause critical storage devices to become unresponsive, potentially leading to application outages, data unavailability, and operational disruptions. Industries relying heavily on high-availability storage, such as finance, telecommunications, healthcare, and government, may experience significant impact if their Linux servers are affected. The inability to reset the controller or recover from the error without manual intervention could increase downtime and complicate incident response. While confidentiality and integrity impacts are not directly indicated, the availability impact is high. Additionally, the complexity of the issue means that recovery might require system reboots or hardware resets, increasing operational costs and risks. European organizations using custom or vendor Linux distributions that include the hisi_sas driver should assess their exposure carefully.

1. Apply the official Linux kernel patches that address this deadlock issue in the hisi_sas driver as soon as they become available. Monitor Linux kernel mailing lists and vendor advisories for updates. 2. Identify and inventory all Linux systems using HiSilicon SAS controllers and the hisi_sas driver. 3. Where patching is not immediately possible, consider isolating affected systems from critical workloads or implementing redundancy to mitigate potential downtime. 4. Monitor kernel logs for hung task warnings related to kworker threads and SAS devices to detect early signs of this issue. 5. Implement proactive hardware error monitoring to detect ECC errors on SAS devices, enabling preemptive maintenance or failover. 6. Coordinate with hardware vendors to confirm firmware compatibility and updates that may reduce ECC errors or improve error handling. 7. Develop operational procedures for safely rebooting or resetting affected systems to recover from deadlocks without data loss. 8. Consider deploying kernel parameters or tuning workqueue timeouts as a temporary workaround, but only under expert guidance to avoid side effects.