CVE-2022-50303 in Linux
Summary
by MITRE • 09/15/2025
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: Fix double release compute pasid
If kfd_process_device_init_vm returns failure after vm is converted to compute vm and vm->pasid set to compute pasid, KFD will not take pdd->drm_file reference. As a result, drm close file handler maybe called to release the compute pasid before KFD process destroy worker to release the same pasid and set vm->pasid to zero, this generates below WARNING backtrace and NULL pointer access.
Add helper amdgpu_amdkfd_gpuvm_set_vm_pasid and call it at the last step of kfd_process_device_init_vm, to ensure vm pasid is the original pasid if acquiring vm failed or is the compute pasid with pdd->drm_file reference taken to avoid double release same pasid.
amdgpu: Failed to create process VM object ida_free called for id=32770 which is not allocated. WARNING: CPU: 57 PID: 72542 at ../lib/idr.c:522 ida_free+0x96/0x140 RIP: 0010:ida_free+0x96/0x140 Call Trace: amdgpu_pasid_free_delayed+0xe1/0x2a0 [amdgpu]
amdgpu_driver_postclose_kms+0x2d8/0x340 [amdgpu]
drm_file_free.part.13+0x216/0x270 [drm]
drm_close_helper.isra.14+0x60/0x70 [drm]
drm_release+0x6e/0xf0 [drm]
__fput+0xcc/0x280 ____fput+0xe/0x20 task_work_run+0x96/0xc0 do_exit+0x3d0/0xc10
BUG: kernel NULL pointer dereference, address: 0000000000000000 RIP: 0010:ida_free+0x76/0x140 Call Trace: amdgpu_pasid_free_delayed+0xe1/0x2a0 [amdgpu]
amdgpu_driver_postclose_kms+0x2d8/0x340 [amdgpu]
drm_file_free.part.13+0x216/0x270 [drm]
drm_close_helper.isra.14+0x60/0x70 [drm]
drm_release+0x6e/0xf0 [drm]
__fput+0xcc/0x280 ____fput+0xe/0x20 task_work_run+0x96/0xc0 do_exit+0x3d0/0xc10
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Analysis
by VulDB Data Team • 01/10/2026
The vulnerability CVE-2022-50303 affects the Linux kernel's graphics subsystem, specifically within the amdgpu driver's interaction with the Kernel Feature Daemon KFD for AMD GPUs. This issue manifests as a double release of compute pasid identifiers during the virtual memory management process, creating a potential for kernel NULL pointer dereference and system instability. The flaw occurs in the drm/amdkfd subsystem where the compute pasid management logic fails to properly synchronize resource cleanup operations. When kfd_process_device_init_vm encounters a failure after converting a virtual memory structure to compute vm and setting vm->pasid to compute pasid, the system does not establish a proper pdd->drm_file reference, leading to a race condition between the drm close file handler and KFD process destroy worker.
The technical root cause involves improper resource lifecycle management where the compute pasid is released twice by different kernel subsystems. The first release occurs through the drm close file handler when it processes the file closure, while the second release happens during KFD process destruction when it attempts to free the same pasid identifier. This creates a scenario where ida_free is called on a pasid that was already freed, resulting in kernel warnings and potential system crashes. The call trace demonstrates the execution path leading to the double release, showing the sequence from amdgpu_pasid_free_delayed through drm_file_free to drm_close_helper and ultimately to the NULL pointer dereference. This vulnerability directly corresponds to CWE-415 Double Free, where the same memory resource is freed twice, and may also exhibit characteristics of CWE-476 NULL Pointer Dereference when the freed memory is accessed.
The operational impact of this vulnerability extends beyond simple system crashes to potential denial of service conditions within graphics-intensive applications and kernel subsystems. When the compute pasid is improperly released, it can cause the amdgpu driver to fail during GPU memory management operations, potentially affecting graphics rendering, compute workloads, and overall system stability. The vulnerability affects systems running Linux kernels with AMDGPU driver support, particularly those utilizing KFD for managing GPU compute processes and virtual memory contexts. Attackers could potentially exploit this through malicious graphics applications or kernel-level code that triggers the specific race condition during GPU process initialization and cleanup phases, though the attack surface is limited to systems with AMD GPU hardware and the specific kernel configuration that enables KFD functionality.
Mitigation strategies focus on ensuring proper resource reference counting and synchronization during virtual memory allocation failures. The fix implemented in the kernel adds a helper function amdgpu_amdkfd_gpuvm_set_vm_pasid that ensures the virtual memory pasid is properly set at the final step of kfd_process_device_init_vm, regardless of whether the process succeeds or fails. This approach prevents the double release by ensuring that if a failure occurs, the pasid management maintains proper reference counts and prevents early cleanup operations from interfering with the final cleanup process. The solution aligns with ATT&CK technique T1059.006 Command and Scripting Interpreter: Python, though not directly applicable, by ensuring proper kernel resource management and preventing unintended code execution paths. Additionally, system administrators should ensure they are running patched kernel versions that include this fix, particularly in environments where GPU compute workloads are intensive and where system stability is critical. The vulnerability also highlights the importance of proper memory management practices in kernel space, emphasizing the need for careful reference counting and synchronization mechanisms when dealing with shared resources like pasid identifiers in graphics drivers.