{"api_version":"1","generated_at":"2026-07-20T14:42:01+00:00","cve":"CVE-2026-64149","urls":{"html":"https://cve.report/CVE-2026-64149","api":"https://cve.report/api/cve/CVE-2026-64149.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-64149","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-64149"},"summary":{"title":"dma-mapping: move dma_map_resource() sanity check into debug code","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ndma-mapping: move dma_map_resource() sanity check into debug code\n\ndma_map_resource() uses pfn_valid() to ensure the range is not RAM.\nHowever, pfn_valid() only checks for availability of the memory map for\na PFN but it does not ensure that the PFN is actually backed by RAM. On\nARM64 with SPARSEMEM (128MB section granularity), MMIO addresses that\nshare a section with RAM will falsely trigger the WARN_ON_ONCE and cause\ndma_map_resource() to return DMA_MAPPING_ERROR.\n\nThis causes a WARNING on Raspberry Pi 4 during spi_bcm2835 probe because\nthe SPI FIFO register (0xfe204004) falls in the same sparsemem section\nas the end of RAM (0xf8000000-0xfbffffff), both in section 31\n(0xf8000000-0xffffffff).\n\nMove the sanity check from dma_map_resource() into debug_dma_map_phys()\nand replace the unreliable pfn_valid() with pfn_valid() &&\n!PageReserved(), which correctly identifies actual usable RAM without\nfalse positives for MMIO regions that happen to have struct pages.\n\nSince dma_map_resource() is dma_map_phys(DMA_ATTR_MMIO), the check\napplies equally to both APIs. Any non-reserved page represents kernel\nmemory to a sufficient degree that using DMA_ATTR_MMIO on it is almost\ncertainly wrong and risks breaking coherency on non-coherent platforms.\nZONE_DEVICE pages used for PCI P2P DMA (MEMORY_DEVICE_PCI_P2PDMA) have\nPageReserved set, so they will not trigger a false positive.\n\nThe check no longer blocks the mapping and uses err_printk() to\nintegrate with dma-debug filtering.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:56","updated_at":"2026-07-19 16:17:56"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/004a777879ff629f6e0ca3d09ad09fa3452bcc4d","name":"https://git.kernel.org/stable/c/004a777879ff629f6e0ca3d09ad09fa3452bcc4d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/181e67bc11c5ec5b87c6c512c2078752b23ca8d4","name":"https://git.kernel.org/stable/c/181e67bc11c5ec5b87c6c512c2078752b23ca8d4","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/af0c3f05866237f7592219bfe05387bc3bfc99b5","name":"https://git.kernel.org/stable/c/af0c3f05866237f7592219bfe05387bc3bfc99b5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-64149","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-64149","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f7326196a781622b33bfbdabb00f5e72b5fb5679 181e67bc11c5ec5b87c6c512c2078752b23ca8d4 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f7326196a781622b33bfbdabb00f5e72b5fb5679 004a777879ff629f6e0ca3d09ad09fa3452bcc4d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f7326196a781622b33bfbdabb00f5e72b5fb5679 af0c3f05866237f7592219bfe05387bc3bfc99b5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.18","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.34 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.11 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * 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":["kernel/dma/debug.c","kernel/dma/mapping.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"181e67bc11c5ec5b87c6c512c2078752b23ca8d4","status":"affected","version":"f7326196a781622b33bfbdabb00f5e72b5fb5679","versionType":"git"},{"lessThan":"004a777879ff629f6e0ca3d09ad09fa3452bcc4d","status":"affected","version":"f7326196a781622b33bfbdabb00f5e72b5fb5679","versionType":"git"},{"lessThan":"af0c3f05866237f7592219bfe05387bc3bfc99b5","status":"affected","version":"f7326196a781622b33bfbdabb00f5e72b5fb5679","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["kernel/dma/debug.c","kernel/dma/mapping.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.18"},{"lessThan":"6.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.34","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.11","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.34","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.11","versionStartIncluding":"6.18","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.18","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndma-mapping: move dma_map_resource() sanity check into debug code\n\ndma_map_resource() uses pfn_valid() to ensure the range is not RAM.\nHowever, pfn_valid() only checks for availability of the memory map for\na PFN but it does not ensure that the PFN is actually backed by RAM. On\nARM64 with SPARSEMEM (128MB section granularity), MMIO addresses that\nshare a section with RAM will falsely trigger the WARN_ON_ONCE and cause\ndma_map_resource() to return DMA_MAPPING_ERROR.\n\nThis causes a WARNING on Raspberry Pi 4 during spi_bcm2835 probe because\nthe SPI FIFO register (0xfe204004) falls in the same sparsemem section\nas the end of RAM (0xf8000000-0xfbffffff), both in section 31\n(0xf8000000-0xffffffff).\n\nMove the sanity check from dma_map_resource() into debug_dma_map_phys()\nand replace the unreliable pfn_valid() with pfn_valid() &&\n!PageReserved(), which correctly identifies actual usable RAM without\nfalse positives for MMIO regions that happen to have struct pages.\n\nSince dma_map_resource() is dma_map_phys(DMA_ATTR_MMIO), the check\napplies equally to both APIs. Any non-reserved page represents kernel\nmemory to a sufficient degree that using DMA_ATTR_MMIO on it is almost\ncertainly wrong and risks breaking coherency on non-coherent platforms.\nZONE_DEVICE pages used for PCI P2P DMA (MEMORY_DEVICE_PCI_P2PDMA) have\nPageReserved set, so they will not trigger a false positive.\n\nThe check no longer blocks the mapping and uses err_printk() to\nintegrate with dma-debug filtering."}],"providerMetadata":{"dateUpdated":"2026-07-19T15:40:39.423Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/181e67bc11c5ec5b87c6c512c2078752b23ca8d4"},{"url":"https://git.kernel.org/stable/c/004a777879ff629f6e0ca3d09ad09fa3452bcc4d"},{"url":"https://git.kernel.org/stable/c/af0c3f05866237f7592219bfe05387bc3bfc99b5"}],"title":"dma-mapping: move dma_map_resource() sanity check into debug code","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-64149","datePublished":"2026-07-19T15:40:39.423Z","dateReserved":"2026-07-19T07:54:57.037Z","dateUpdated":"2026-07-19T15:40:39.423Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:56","lastModifiedDate":"2026-07-19 16:17:56","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"64149","Ordinal":"1","Title":"dma-mapping: move dma_map_resource() sanity check into debug cod","CVE":"CVE-2026-64149","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"64149","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\ndma-mapping: move dma_map_resource() sanity check into debug code\n\ndma_map_resource() uses pfn_valid() to ensure the range is not RAM.\nHowever, pfn_valid() only checks for availability of the memory map for\na PFN but it does not ensure that the PFN is actually backed by RAM. On\nARM64 with SPARSEMEM (128MB section granularity), MMIO addresses that\nshare a section with RAM will falsely trigger the WARN_ON_ONCE and cause\ndma_map_resource() to return DMA_MAPPING_ERROR.\n\nThis causes a WARNING on Raspberry Pi 4 during spi_bcm2835 probe because\nthe SPI FIFO register (0xfe204004) falls in the same sparsemem section\nas the end of RAM (0xf8000000-0xfbffffff), both in section 31\n(0xf8000000-0xffffffff).\n\nMove the sanity check from dma_map_resource() into debug_dma_map_phys()\nand replace the unreliable pfn_valid() with pfn_valid() &&\n!PageReserved(), which correctly identifies actual usable RAM without\nfalse positives for MMIO regions that happen to have struct pages.\n\nSince dma_map_resource() is dma_map_phys(DMA_ATTR_MMIO), the check\napplies equally to both APIs. Any non-reserved page represents kernel\nmemory to a sufficient degree that using DMA_ATTR_MMIO on it is almost\ncertainly wrong and risks breaking coherency on non-coherent platforms.\nZONE_DEVICE pages used for PCI P2P DMA (MEMORY_DEVICE_PCI_P2PDMA) have\nPageReserved set, so they will not trigger a false positive.\n\nThe check no longer blocks the mapping and uses err_printk() to\nintegrate with dma-debug filtering.","Type":"Description","Title":"dma-mapping: move dma_map_resource() sanity check into debug cod"}]}}}