CVE-2024-27003 is a vulnerability identified in the Linux kernel related to the clock (clk) subsystem's runtime power management (PM) handling. Specifically, the issue arises when the kernel attempts to print the clk_summary via debugfs without ensuring that all devices are runtime resumed beforehand. Runtime PM allows devices to be suspended and resumed dynamically to save power. The vulnerability occurs because the code path responsible for printing the clk_summary does not properly synchronize device runtime states, leading to a potential deadlock scenario. This deadlock can happen if one thread is resuming a device to print its clock state while another thread is concurrently resuming the same device, such as during screen activation and display driver startup. Additionally, the previous implementation incorrectly used clk_pm_runtime_get() and clk_pm_runtime_put() calls in this path, which were unnecessary and introduced a bug where the return value of clk_pm_runtime_get() was not checked. This oversight could cause an RPM (runtime PM) count underflow on error paths, potentially destabilizing device power management. The fix involves removing these superfluous calls and ensuring that all devices are runtime resumed before walking the clock tree, thereby preventing deadlocks and maintaining proper reference counting. This vulnerability affects Linux kernel versions identified by the commit hash 1bb294a7981c737e2311a78e4086635ac0220ace and similar versions prior to the patch. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the impact of CVE-2024-27003 depends largely on their reliance on Linux-based systems, especially those using runtime power management features extensively, such as embedded devices, servers, and desktops running Linux kernels vulnerable to this issue. The deadlock caused by this vulnerability can lead to system hangs or freezes during device resume operations, potentially affecting availability of critical services or user-facing applications. Systems involved in display management (e.g., laptops, kiosks, digital signage) are particularly at risk since the example scenario involves screen activation and display driver startup. While this vulnerability does not directly expose confidentiality or integrity risks, the availability impact could disrupt business operations, especially in environments requiring high uptime or real-time responsiveness. Industrial control systems, telecommunications infrastructure, and cloud services running vulnerable Linux kernels could experience degraded performance or outages. Since no known exploits exist yet, the immediate risk is moderate, but the potential for future exploitation to cause denial-of-service conditions warrants prompt attention.

European organizations should prioritize updating their Linux kernel versions to include the patch that resolves CVE-2024-27003. This involves applying the latest stable kernel releases or vendor-provided updates that address the runtime PM deadlock issue. For environments where immediate patching is not feasible, administrators should monitor system logs for signs of deadlocks or hangs related to device resume operations and consider temporarily disabling runtime power management features for affected devices as a workaround. Additionally, thorough testing of kernel updates in staging environments is recommended to ensure compatibility and stability. Organizations should also maintain robust backup and recovery procedures to mitigate potential availability impacts. Vendors and maintainers of Linux distributions should be engaged to expedite patch deployment. Finally, monitoring security advisories and subscribing to Linux kernel mailing lists can help organizations stay informed about further developments or exploit disclosures related to this vulnerability.