CVE-2024-47143: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-47143 is a vulnerability in the Linux kernel's DMA debugging functionality, discovered in January 2025. The issue involves a potential deadlock scenario in the DMA debug API when the radix_lock is held while holding dma_hash_entry[idx].lock. This vulnerability affects multiple versions of the Linux kernel, including versions up to 5.10.231, from 5.11 to 5.15.174, 5.16 to 6.1.120, 6.2 to 6.6.66, and 6.7 to 6.12.5 (NVD).

The vulnerability stems from an improper locking mechanism in the kernel's DMA debugging code. The issue occurs when the DMA debug API is called while holding rq_lock(), creating a potential deadlock between the radix_lock and dma_hash_entry locks. The deadlock can manifest in two scenarios: when extending the radix tree and attempting to wake up kswapd, or during perf_event_task_sched_out() operations involving Arm Coresight hwtracing driver backends. The vulnerability has been assigned a CVSS v3.1 base score of 5.5 (Medium) with a vector of CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (NVD).

The vulnerability can lead to system deadlocks when using DMA debugging features, particularly affecting systems using Arm Coresight hwtracing driver backends. The impact is primarily on system availability, as indicated by the CVSS scoring which shows no impact on confidentiality or integrity, but high impact on availability (NVD).

The vulnerability has been patched by modifying the check_unmap() function to call dma_entry_free() after put_hash_bucket(), preventing the ABBA deadlock between bucket_lock and radix_lock. The fix has been implemented in various kernel versions through patches (Kernel Patch).