In the Linux kernel, the following vulnerability has been resolved:
dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning
When CONFIG_DMA_API_DEBUG_SG is enabled, importing a udmabuf into a DRM driver (e.g. amdgpu for video playback in GNOME Videos / Showtime) triggers a spurious warning:
DMA-API: amdgpu 0000:03:00.0: cacheline tracking EEXIST, overlapping mappings arent supported WARNING: kernel/dma/debug.c:619 at add_dma_entry+0x473/0x5f0
The call chain is:
amdgpu_cs_ioctl -> amdgpu_ttm_backend_bind -> dma_buf_map_attachment -> [udmabuf] map_udmabuf -> get_sg_table -> dma_map_sgtable(dev, sg, direction, 0) // attrs=0 -> debug_dma_map_sg -> add_dma_entry -> EEXIST
This happens because udmabuf builds a per-page scatter-gather list via sg_set_folio(). When begin_cpu_udmabuf() has already created an sg table mapped for the misc device, and an importer such as amdgpu maps the same pages for its own device via map_udmabuf(), the DMA debug infrastructure sees two active mappings whose physical addresses share cacheline boundaries and warns about the overlap.
The DMA_ATTR_SKIP_CPU_SYNC flag suppresses this check in add_dma_entry() because it signals that no CPU cache maintenance is performed at map/unmap time, making the cacheline overlap harmless.
All other major dma-buf exporters already pass this flag:
The CPU sync at map/unmap time is also redundant for udmabuf: begin_cpu_udmabuf() and end_cpu_udmabuf() already perform explicit cache synchronization via dma_sync_sgtable_for_cpu/device() when CPU access is requested through the dma-buf interface.
Pass DMA_ATTR_SKIP_CPU_SYNC to dma_map_sgtable() and dma_unmap_sgtable() in udmabuf to suppress the spurious warning and skip the redundant sync.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Linux-allwinner-5.19 | Ubuntu | jammy | * |
| Linux-allwinner-5.19 | Ubuntu | upstream | * |
| Linux-aws-5.0 | Ubuntu | esm-infra/bionic | * |
| Linux-aws-5.0 | Ubuntu | upstream | * |
| Linux-aws-5.11 | Ubuntu | esm-infra/focal | * |
| Linux-aws-5.11 | Ubuntu | upstream | * |
| Linux-aws-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-aws-5.13 | Ubuntu | upstream | * |
| Linux-aws-5.19 | Ubuntu | jammy | * |
| Linux-aws-5.19 | Ubuntu | upstream | * |
| Linux-aws-5.3 | Ubuntu | esm-infra/bionic | * |
| Linux-aws-5.3 | Ubuntu | upstream | * |
| Linux-aws-5.8 | Ubuntu | esm-infra/focal | * |
| Linux-aws-5.8 | Ubuntu | upstream | * |
| Linux-aws-6.2 | Ubuntu | jammy | * |
| Linux-aws-6.2 | Ubuntu | upstream | * |
| Linux-aws-6.5 | Ubuntu | jammy | * |
| Linux-aws-6.5 | Ubuntu | upstream | * |
| Linux-azure | Ubuntu | esm-infra/bionic | * |
| Linux-azure-5.11 | Ubuntu | esm-infra/focal | * |
| Linux-azure-5.11 | Ubuntu | upstream | * |
| Linux-azure-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-azure-5.13 | Ubuntu | upstream | * |
| Linux-azure-5.19 | Ubuntu | jammy | * |
| Linux-azure-5.19 | Ubuntu | upstream | * |
| Linux-azure-5.3 | Ubuntu | esm-infra/bionic | * |
| Linux-azure-5.3 | Ubuntu | upstream | * |
| Linux-azure-5.8 | Ubuntu | esm-infra/focal | * |
| Linux-azure-5.8 | Ubuntu | upstream | * |
| Linux-azure-6.11 | Ubuntu | noble | * |
| Linux-azure-6.11 | Ubuntu | upstream | * |
| Linux-azure-6.2 | Ubuntu | jammy | * |
| Linux-azure-6.2 | Ubuntu | upstream | * |
| Linux-azure-6.5 | Ubuntu | jammy | * |
| Linux-azure-6.5 | Ubuntu | upstream | * |
| Linux-azure-edge | Ubuntu | esm-infra/bionic | * |
| Linux-azure-edge | Ubuntu | upstream | * |
| Linux-azure-fde | Ubuntu | esm-infra/focal | * |
| Linux-azure-fde-5.19 | Ubuntu | jammy | * |
| Linux-azure-fde-5.19 | Ubuntu | upstream | * |
| Linux-azure-fde-6.2 | Ubuntu | jammy | * |
| Linux-azure-fde-6.2 | Ubuntu | upstream | * |
| Linux-gcp | Ubuntu | esm-infra/bionic | * |
| Linux-gcp-5.11 | Ubuntu | esm-infra/focal | * |
| Linux-gcp-5.11 | Ubuntu | upstream | * |
| Linux-gcp-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-gcp-5.13 | Ubuntu | upstream | * |
| Linux-gcp-5.19 | Ubuntu | jammy | * |
| Linux-gcp-5.19 | Ubuntu | upstream | * |
| Linux-gcp-5.3 | Ubuntu | esm-infra/bionic | * |
| Linux-gcp-5.3 | Ubuntu | upstream | * |
| Linux-gcp-5.8 | Ubuntu | esm-infra/focal | * |
| Linux-gcp-5.8 | Ubuntu | upstream | * |
| Linux-gcp-6.11 | Ubuntu | noble | * |
| Linux-gcp-6.11 | Ubuntu | upstream | * |
| Linux-gcp-6.2 | Ubuntu | jammy | * |
| Linux-gcp-6.2 | Ubuntu | upstream | * |
| Linux-gcp-6.5 | Ubuntu | jammy | * |
| Linux-gcp-6.5 | Ubuntu | upstream | * |
| Linux-gke | Ubuntu | esm-infra/focal | * |
| Linux-gke-4.15 | Ubuntu | esm-infra/bionic | * |
| Linux-gke-4.15 | Ubuntu | upstream | * |
| Linux-gke-5.15 | Ubuntu | esm-infra/focal | * |
| Linux-gke-5.15 | Ubuntu | upstream | * |
| Linux-gke-5.4 | Ubuntu | esm-infra/bionic | * |
| Linux-gke-5.4 | Ubuntu | upstream | * |
| Linux-gkeop | Ubuntu | esm-infra/focal | * |
| Linux-gkeop-5.15 | Ubuntu | esm-infra/focal | * |
| Linux-gkeop-5.4 | Ubuntu | esm-infra/bionic | * |
| Linux-gkeop-5.4 | Ubuntu | upstream | * |
| Linux-hwe | Ubuntu | esm-infra/bionic | * |
| Linux-hwe-5.11 | Ubuntu | esm-infra/focal | * |
| Linux-hwe-5.11 | Ubuntu | upstream | * |
| Linux-hwe-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-hwe-5.13 | Ubuntu | upstream | * |
| Linux-hwe-5.19 | Ubuntu | jammy | * |
| Linux-hwe-5.19 | Ubuntu | upstream | * |
| Linux-hwe-5.8 | Ubuntu | esm-infra/focal | * |
| Linux-hwe-5.8 | Ubuntu | upstream | * |
| Linux-hwe-6.11 | Ubuntu | noble | * |
| Linux-hwe-6.11 | Ubuntu | upstream | * |
| Linux-hwe-6.2 | Ubuntu | jammy | * |
| Linux-hwe-6.2 | Ubuntu | upstream | * |
| Linux-hwe-6.5 | Ubuntu | jammy | * |
| Linux-hwe-6.5 | Ubuntu | upstream | * |
| Linux-hwe-edge | Ubuntu | esm-infra-legacy/xenial | * |
| Linux-hwe-edge | Ubuntu | esm-infra/bionic | * |
| Linux-hwe-edge | Ubuntu | upstream | * |
| Linux-intel-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-intel-5.13 | Ubuntu | upstream | * |
| Linux-intel-iot-realtime | Ubuntu | jammy | * |
| Linux-lowlatency-hwe-5.19 | Ubuntu | jammy | * |
| Linux-lowlatency-hwe-5.19 | Ubuntu | upstream | * |
| Linux-lowlatency-hwe-6.11 | Ubuntu | noble | * |
| Linux-lowlatency-hwe-6.11 | Ubuntu | upstream | * |
| Linux-lowlatency-hwe-6.2 | Ubuntu | jammy | * |
| Linux-lowlatency-hwe-6.2 | Ubuntu | upstream | * |
| Linux-lowlatency-hwe-6.5 | Ubuntu | jammy | * |
| Linux-lowlatency-hwe-6.5 | Ubuntu | upstream | * |
| Linux-nvidia-6.11 | Ubuntu | noble | * |
| Linux-nvidia-6.11 | Ubuntu | upstream | * |
| Linux-nvidia-6.2 | Ubuntu | jammy | * |
| Linux-nvidia-6.2 | Ubuntu | upstream | * |
| Linux-nvidia-6.5 | Ubuntu | jammy | * |
| Linux-nvidia-6.5 | Ubuntu | upstream | * |
| Linux-oem | Ubuntu | esm-infra/bionic | * |
| Linux-oem | Ubuntu | upstream | * |
| Linux-oem-5.10 | Ubuntu | esm-infra/focal | * |
| Linux-oem-5.10 | Ubuntu | upstream | * |
| Linux-oem-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-oem-5.13 | Ubuntu | upstream | * |
| Linux-oem-5.14 | Ubuntu | esm-infra/focal | * |
| Linux-oem-5.14 | Ubuntu | upstream | * |
| Linux-oem-5.17 | Ubuntu | jammy | * |
| Linux-oem-5.17 | Ubuntu | upstream | * |
| Linux-oem-5.6 | Ubuntu | esm-infra/focal | * |
| Linux-oem-5.6 | Ubuntu | upstream | * |
| Linux-oem-6.0 | Ubuntu | jammy | * |
| Linux-oem-6.0 | Ubuntu | upstream | * |
| Linux-oem-6.1 | Ubuntu | jammy | * |
| Linux-oem-6.1 | Ubuntu | upstream | * |
| Linux-oem-6.11 | Ubuntu | noble | * |
| Linux-oem-6.11 | Ubuntu | upstream | * |
| Linux-oem-6.5 | Ubuntu | jammy | * |
| Linux-oem-6.5 | Ubuntu | upstream | * |
| Linux-oem-6.8 | Ubuntu | noble | * |
| Linux-oem-6.8 | Ubuntu | upstream | * |
| Linux-oracle-5.0 | Ubuntu | esm-infra/bionic | * |
| Linux-oracle-5.0 | Ubuntu | upstream | * |
| Linux-oracle-5.11 | Ubuntu | esm-infra/focal | * |
| Linux-oracle-5.11 | Ubuntu | upstream | * |
| Linux-oracle-5.13 | Ubuntu | esm-infra/focal | * |
| Linux-oracle-5.13 | Ubuntu | upstream | * |
| Linux-oracle-5.3 | Ubuntu | esm-infra/bionic | * |
| Linux-oracle-5.3 | Ubuntu | upstream | * |
| Linux-oracle-5.8 | Ubuntu | esm-infra/focal | * |
| Linux-oracle-5.8 | Ubuntu | upstream | * |
| Linux-oracle-6.5 | Ubuntu | jammy | * |
| Linux-oracle-6.5 | Ubuntu | upstream | * |
| Linux-raspi-realtime | Ubuntu | noble | * |
| Linux-raspi2 | Ubuntu | esm-infra/focal | * |
| Linux-raspi2 | Ubuntu | upstream | * |
| Linux-realtime | Ubuntu | jammy | * |
| Linux-realtime | Ubuntu | noble | * |
| Linux-riscv | Ubuntu | esm-infra/focal | * |
| Linux-riscv | Ubuntu | jammy | * |
| Linux-riscv | Ubuntu | noble | * |
| Linux-riscv-5.11 | Ubuntu | esm-infra/focal | * |
| Linux-riscv-5.11 | Ubuntu | upstream | * |
| Linux-riscv-5.19 | Ubuntu | jammy | * |
| Linux-riscv-5.19 | Ubuntu | upstream | * |
| Linux-riscv-5.8 | Ubuntu | esm-infra/focal | * |
| Linux-riscv-5.8 | Ubuntu | upstream | * |
| Linux-riscv-6.14 | Ubuntu | noble | * |
| Linux-riscv-6.14 | Ubuntu | upstream | * |
| Linux-riscv-6.5 | Ubuntu | jammy | * |
| Linux-riscv-6.5 | Ubuntu | upstream | * |
| Linux-starfive-5.19 | Ubuntu | jammy | * |
| Linux-starfive-5.19 | Ubuntu | upstream | * |
| Linux-starfive-6.2 | Ubuntu | jammy | * |
| Linux-starfive-6.2 | Ubuntu | upstream | * |
| Linux-starfive-6.5 | Ubuntu | jammy | * |
| Linux-starfive-6.5 | Ubuntu | upstream | * |