{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64590","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T15:36:31.798Z","datePublished":"2026-08-06T07:13:47.888Z","dateUpdated":"2026-08-23T12:45:45.786Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-23T12:45:45.786Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning\n\nWhen CONFIG_DMA_API_DEBUG_SG is enabled, importing a udmabuf into a DRM\ndriver (e.g. amdgpu for video playback in GNOME Videos / Showtime)\ntriggers a spurious warning:\n\n  DMA-API: amdgpu 0000:03:00.0: cacheline tracking EEXIST, \\\n      overlapping mappings aren't supported\n  WARNING: kernel/dma/debug.c:619 at add_dma_entry+0x473/0x5f0\n\nThe call chain is:\n\n  amdgpu_cs_ioctl\n   -> amdgpu_ttm_backend_bind\n    -> dma_buf_map_attachment\n     -> [udmabuf] map_udmabuf -> get_sg_table\n      -> dma_map_sgtable(dev, sg, direction, 0)  // attrs=0\n       -> debug_dma_map_sg -> add_dma_entry -> EEXIST\n\nThis happens because udmabuf builds a per-page scatter-gather list via\nsg_set_folio().  When begin_cpu_udmabuf() has already created an sg\ntable mapped for the misc device, and an importer such as amdgpu maps\nthe same pages for its own device via map_udmabuf(), the DMA debug\ninfrastructure sees two active mappings whose physical addresses share\ncacheline boundaries and warns about the overlap.\n\nThe DMA_ATTR_SKIP_CPU_SYNC flag suppresses this check in\nadd_dma_entry() because it signals that no CPU cache maintenance is\nperformed at map/unmap time, making the cacheline overlap harmless.\n\nAll other major dma-buf exporters already pass this flag:\n  - drm_gem_map_dma_buf() passes DMA_ATTR_SKIP_CPU_SYNC\n  - amdgpu_dma_buf_map() passes DMA_ATTR_SKIP_CPU_SYNC\n\nThe CPU sync at map/unmap time is also redundant for udmabuf:\nbegin_cpu_udmabuf() and end_cpu_udmabuf() already perform explicit\ncache synchronization via dma_sync_sgtable_for_cpu/device() when CPU\naccess is requested through the dma-buf interface.\n\nPass DMA_ATTR_SKIP_CPU_SYNC to dma_map_sgtable() and\ndma_unmap_sgtable() in udmabuf to suppress the spurious warning and\nskip the redundant sync."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/dma-buf/udmabuf.c"],"versions":[{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"4a7c644e632741c2a3116a0d3da6c11de957a6ba","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"01126abc11bcc6a45b664293b0b5df715be911d7","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"dd7f1e572f44d3d039dc77e3989f537196c3bf52","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"0db56e7eae932f8e2f3eb44ad1a63633d8f504f8","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"d6552f5cff795d60e629f37513ecf23d88fd2f82","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"34696563461c9a23177feb6d8aff43f4c0510278","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"0449a6583c0ee76778d314e4e82f166fc97fa9d8","status":"affected","versionType":"git"},{"version":"284562e1f34874e267d4f499362c3816f8f6bc3f","lessThan":"504e2b4ab97a51d56d966cd36d0997ad30b65b2d","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/dma-buf/udmabuf.c"],"versions":[{"version":"5.6","status":"affected"},{"version":"0","lessThan":"5.6","status":"unaffected","versionType":"semver"},{"version":"5.10.266","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.217","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.184","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.148","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.96","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.39","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.4","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"5.10.266"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"5.15.217"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.1.184"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.6.148"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.6","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/4a7c644e632741c2a3116a0d3da6c11de957a6ba"},{"url":"https://git.kernel.org/stable/c/01126abc11bcc6a45b664293b0b5df715be911d7"},{"url":"https://git.kernel.org/stable/c/dd7f1e572f44d3d039dc77e3989f537196c3bf52"},{"url":"https://git.kernel.org/stable/c/0db56e7eae932f8e2f3eb44ad1a63633d8f504f8"},{"url":"https://git.kernel.org/stable/c/d6552f5cff795d60e629f37513ecf23d88fd2f82"},{"url":"https://git.kernel.org/stable/c/34696563461c9a23177feb6d8aff43f4c0510278"},{"url":"https://git.kernel.org/stable/c/0449a6583c0ee76778d314e4e82f166fc97fa9d8"},{"url":"https://git.kernel.org/stable/c/504e2b4ab97a51d56d966cd36d0997ad30b65b2d"}],"title":"dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning","x_generator":{"engine":"bippy-1.2.0"}}}}