CVE-2021-4460

A flaw was found in the Linux kernel’s AMD Kernel Fusion Driver (amdkfd) within the drm subsystem. When either get_num_sdma_queues() or get_num_xgmi_sdma_queues() returned 0, the driver performed a bit shift where the number of bits shifted equaled the operand width. Such a shift is undefined behavior in C and can lead to incorrect values being used in subsequent logic.A local user with the ability to exercise the affected kernel APIs could trigger unintended behavior in the DRM/AMD GPU driver, which may result in a kernel crash and impact system availability

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.

To mitigate this issue, the amdkfd kernel module can be prevented from loading by blacklisting it. Create a file /etc/modprobe.d/blacklist-amdkfd.conf with the content blacklist amdkfd. A system reboot is required for this change to take effect. This may impact functionality that relies on the AMDGPU kernel graphics driver.