CVE-2024-49989 is a vulnerability identified in the Linux kernel specifically affecting the AMD GPU (amdgpu) driver module. The issue arises from a double free bug during the unloading of the amdgpu kernel module. In detail, the Linux kernel's Direct Rendering Manager (DRM) subsystem for AMD graphics cards improperly handles the freeing of encoder resources linked to display endpoints. Flexible endpoints reuse Display Interface Generators (DIGs) from inflexible endpoints, and the vulnerability stems from freeing both flexible and inflexible endpoint encoders, leading to a double free condition. This double free occurs when the amdgpu module is unloaded, causing the kernel to attempt to free the same memory region twice. The kernel logs provided indicate the fault occurs in the __slab_free function, which manages kernel memory deallocation, and the stack trace shows repeated calls to dcn10_link_encoder_destroy and related amdgpu functions. Such a double free can lead to kernel memory corruption, potentially causing system crashes (kernel panic), denial of service, or in some cases, could be leveraged for privilege escalation or arbitrary code execution if exploited with crafted inputs. However, this vulnerability requires unloading the amdgpu module, which typically requires root privileges, and no public exploits are currently known. The vulnerability affects specific Linux kernel versions identified by commit hashes, and a patch has been released to fix the improper freeing logic by ensuring only encoders of inflexible links are freed, preventing the double free scenario.

For European organizations, the impact of CVE-2024-49989 depends largely on their use of Linux systems with AMD GPUs, particularly in environments where kernel modules might be dynamically unloaded and reloaded, such as development, testing, or certain server configurations. The vulnerability can cause system instability or crashes, leading to denial of service. In critical infrastructure or data center environments relying on AMD GPUs for compute or graphics tasks, unexpected kernel panics could disrupt services. Although exploitation requires privileged access to unload kernel modules, an attacker who gains such access could trigger the vulnerability to cause system outages or potentially escalate privileges if combined with other vulnerabilities. This risk is heightened in multi-tenant environments or cloud providers using AMD GPU-enabled Linux hosts. Additionally, organizations running Linux distributions with affected kernel versions must apply patches promptly to maintain system integrity and availability. The lack of known exploits reduces immediate risk, but the vulnerability's presence in the kernel code base means it could be targeted in the future.

1. Apply the official Linux kernel patches that fix the double free in the amdgpu module as soon as they are available from trusted sources or distribution maintainers. 2. Avoid unloading the amdgpu kernel module unless necessary, especially on production systems, to reduce exposure. 3. Restrict root or administrative access to trusted personnel only, as unloading kernel modules requires elevated privileges. 4. Monitor system logs for unusual kernel errors or crashes related to amdgpu or module unloading activities. 5. For environments using AMD GPUs extensively, consider implementing kernel live patching solutions to apply fixes without downtime. 6. Conduct regular audits of kernel module usage and ensure that system configurations do not allow unnecessary module unloading. 7. Employ security mechanisms such as SELinux or AppArmor to limit the capabilities of processes that could attempt to unload kernel modules. 8. Stay informed through Linux kernel mailing lists and security advisories for any updates or exploit reports related to this vulnerability.