CVE-2022-49773 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix optc2_configure warning on dcn314
[Why]
dcn314 uses optc2_configure_crc() that wraps optc1_configure_crc() + set additional registers not applicable to dcn314. It's not critical but when used leads to warning like: WARNING: drivers/gpu/drm/amd/amdgpu/../display/dc/dc_helper.c Call Trace: <TASK> generic_reg_set_ex+0x6d/0xe0 [amdgpu]
optc2_configure_crc+0x60/0x80 [amdgpu]
dc_stream_configure_crc+0x129/0x150 [amdgpu]
amdgpu_dm_crtc_configure_crc_source+0x5d/0xe0 [amdgpu]
[How]
Use optc1_configure_crc() directly
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/07/2025
The vulnerability CVE-2022-49773 represents a minor but noteworthy issue within the Linux kernel's AMD display driver subsystem, specifically affecting the display core helper functionality. This flaw manifests in the drm/amd/display module where the optc2_configure_crc() function attempts to execute code paths that are incompatible with the dcn314 hardware configuration. The issue stems from a design inconsistency where the function wraps both optc1_configure_crc() and additional register configurations that do not apply to dcn314 architectures, creating a mismatch between the expected and actual hardware behavior. Such inconsistencies in driver code can lead to warning messages that, while not immediately critical, indicate underlying architectural mismatches that may propagate into more serious issues under specific operational conditions.
The technical implementation of this vulnerability demonstrates a clear case of improper function delegation within the AMD display driver framework. When the system attempts to configure CRC (Cyclic Redundancy Check) functionality for display streams on dcn314 hardware, the optc2_configure_crc() function executes code that includes calls to optc1_configure_crc() followed by register modifications that are irrelevant to the dcn314 architecture. This creates a warning condition in the kernel logs as evidenced by the call trace showing generic_reg_set_ex being invoked through the chain of optc2_configure_crc() → dc_stream_configure_crc() → amdgpu_dm_crtc_configure_crc_source(). The warning originates from the display/dc/dc_helper.c file and represents a code path that should not be executed on dcn314 hardware, indicating a missing hardware-specific conditional logic or function selection mechanism.
From an operational perspective, while this vulnerability does not represent an immediate security risk or system compromise, it does demonstrate poor code maintenance and hardware abstraction practices within the AMD display driver. The warning messages generated can clutter kernel logs and potentially mask more serious issues, making system monitoring and debugging more challenging for administrators. The impact extends beyond simple logging as it indicates a broader architectural concern with how hardware-specific code paths are managed within the driver framework, potentially affecting driver stability and maintainability. This type of issue commonly falls under CWE-691, which addresses insufficient control flow management in software systems, and could be categorized under ATT&CK technique T1547.001 for registry modification or T1059.001 for command and scripting interpreter, though the specific context here relates more to driver code quality than direct attack vectors.
The recommended mitigation strategy involves implementing a direct call to optc1_configure_crc() instead of the problematic optc2_configure_crc() function when operating on dcn314 hardware. This approach eliminates the unnecessary register configuration operations that do not apply to the target architecture and resolves the warning condition through proper hardware abstraction. The solution requires adding appropriate hardware detection and function selection logic that determines the correct CRC configuration function based on the detected display controller version. This fix aligns with best practices for device driver development and follows the principle of least privilege in kernel space operations, ensuring that only relevant code paths are executed for specific hardware configurations. The implementation should include proper conditional compilation or runtime detection mechanisms to ensure that the correct function is called based on the detected hardware version, thereby preventing similar issues across other display controller variants.