{"api_version":"1","generated_at":"2026-08-06T13:11:17+00:00","cve":"CVE-2026-64590","urls":{"html":"https://cve.report/CVE-2026-64590","api":"https://cve.report/api/cve/CVE-2026-64590.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64590","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64590"},"summary":{"title":"dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST warning","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-06 08:16:34","updated_at":"2026-08-06 08:16:34"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/34696563461c9a23177feb6d8aff43f4c0510278","name":"https://git.kernel.org/stable/c/34696563461c9a23177feb6d8aff43f4c0510278","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d6552f5cff795d60e629f37513ecf23d88fd2f82","name":"https://git.kernel.org/stable/c/d6552f5cff795d60e629f37513ecf23d88fd2f82","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0449a6583c0ee76778d314e4e82f166fc97fa9d8","name":"https://git.kernel.org/stable/c/0449a6583c0ee76778d314e4e82f166fc97fa9d8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0db56e7eae932f8e2f3eb44ad1a63633d8f504f8","name":"https://git.kernel.org/stable/c/0db56e7eae932f8e2f3eb44ad1a63633d8f504f8","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/504e2b4ab97a51d56d966cd36d0997ad30b65b2d","name":"https://git.kernel.org/stable/c/504e2b4ab97a51d56d966cd36d0997ad30b65b2d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64590","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64590","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 284562e1f34874e267d4f499362c3816f8f6bc3f 0db56e7eae932f8e2f3eb44ad1a63633d8f504f8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 284562e1f34874e267d4f499362c3816f8f6bc3f d6552f5cff795d60e629f37513ecf23d88fd2f82 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 284562e1f34874e267d4f499362c3816f8f6bc3f 34696563461c9a23177feb6d8aff43f4c0510278 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 284562e1f34874e267d4f499362c3816f8f6bc3f 0449a6583c0ee76778d314e4e82f166fc97fa9d8 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 284562e1f34874e267d4f499362c3816f8f6bc3f 504e2b4ab97a51d56d966cd36d0997ad30b65b2d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.6","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.6 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.148 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.96 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.39 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.4 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2-rc1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/dma-buf/udmabuf.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"0db56e7eae932f8e2f3eb44ad1a63633d8f504f8","status":"affected","version":"284562e1f34874e267d4f499362c3816f8f6bc3f","versionType":"git"},{"lessThan":"d6552f5cff795d60e629f37513ecf23d88fd2f82","status":"affected","version":"284562e1f34874e267d4f499362c3816f8f6bc3f","versionType":"git"},{"lessThan":"34696563461c9a23177feb6d8aff43f4c0510278","status":"affected","version":"284562e1f34874e267d4f499362c3816f8f6bc3f","versionType":"git"},{"lessThan":"0449a6583c0ee76778d314e4e82f166fc97fa9d8","status":"affected","version":"284562e1f34874e267d4f499362c3816f8f6bc3f","versionType":"git"},{"lessThan":"504e2b4ab97a51d56d966cd36d0997ad30b65b2d","status":"affected","version":"284562e1f34874e267d4f499362c3816f8f6bc3f","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/dma-buf/udmabuf.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.6"},{"lessThan":"5.6","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.148","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.96","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.39","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2-rc1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.148","versionStartIncluding":"5.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.96","versionStartIncluding":"5.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.39","versionStartIncluding":"5.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.4","versionStartIncluding":"5.6","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2-rc1","versionStartIncluding":"5.6","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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."}],"providerMetadata":{"dateUpdated":"2026-08-06T07:13:47.888Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64590","datePublished":"2026-08-06T07:13:47.888Z","dateReserved":"2026-07-19T15:36:31.798Z","dateUpdated":"2026-08-06T07:13:47.888Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-06 08:16:34","lastModifiedDate":"2026-08-06 08:16:34","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64590","Ordinal":"1","Title":"dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST","CVE":"CVE-2026-64590","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64590","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"dma-buf/udmabuf: skip redundant cpu sync to fix cacheline EEXIST"}]}}}