Answer in brief
CVE-2026-64590 records a Unknown severity vulnerability in dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=284562e1f34874e267d4f499362c3816f8f6bc3f <0db56e7eae932f8e2f3eb44ad1a63633d8f504f8 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <d6552f5cff795d60e629f37513ecf23d88fd2f82 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <34696563461c9a23177feb6d8aff43f4c0510278 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <0449a6583c0ee76778d314e4e82f166fc97fa9d8 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <504e2b4ab97a51d56d966cd36d0997ad30b65b2d | 0db56e7eae932f8e2f3eb44ad1a63633d8f504f8, d6552f5cff795d60e629f37513ecf23d88fd2f82, 34696563461c9a23177feb6d8aff43f4c0510278, 0449a6583c0ee76778d314e4e82f166fc97fa9d8, 504e2b4ab97a51d56d966cd36d0997ad30b65b2d |
| Linux/Linuxgeneric | 5.6 | Not reported |
| Linux/Linuxgeneric | >=284562e1f34874e267d4f499362c3816f8f6bc3f <4a7c644e632741c2a3116a0d3da6c11de957a6ba || >=284562e1f34874e267d4f499362c3816f8f6bc3f <01126abc11bcc6a45b664293b0b5df715be911d7 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <dd7f1e572f44d3d039dc77e3989f537196c3bf52 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <0db56e7eae932f8e2f3eb44ad1a63633d8f504f8 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <d6552f5cff795d60e629f37513ecf23d88fd2f82 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <34696563461c9a23177feb6d8aff43f4c0510278 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <0449a6583c0ee76778d314e4e82f166fc97fa9d8 || >=284562e1f34874e267d4f499362c3816f8f6bc3f <504e2b4ab97a51d56d966cd36d0997ad30b65b2d | 4a7c644e632741c2a3116a0d3da6c11de957a6ba, 01126abc11bcc6a45b664293b0b5df715be911d7, dd7f1e572f44d3d039dc77e3989f537196c3bf52, 0db56e7eae932f8e2f3eb44ad1a63633d8f504f8, d6552f5cff795d60e629f37513ecf23d88fd2f82, 34696563461c9a23177feb6d8aff43f4c0510278, 0449a6583c0ee76778d314e4e82f166fc97fa9d8, 504e2b4ab97a51d56d966cd36d0997ad30b65b2d |
Published upstream
Aug 6, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 23, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 6, 2026
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 aren't 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: - drm_gem_map_dma_buf() passes DMA_ATTR_SKIP_CPU_SYNC - amdgpu_dma_buf_map() passes DMA_ATTR_SKIP_CPU_SYNC 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.
Quoted source text, attributed separately from HOL analysis.