{"id":"CVE-2021-47140","details":"In the Linux kernel, the following vulnerability has been resolved:\n\niommu/amd: Clear DMA ops when switching domain\n\nSince commit 08a27c1c3ecf (\"iommu: Add support to change default domain\nof an iommu group\") a user can switch a device between IOMMU and direct\nDMA through sysfs. This doesn't work for AMD IOMMU at the moment because\ndev-\u003edma_ops is not cleared when switching from a DMA to an identity\nIOMMU domain. The DMA layer thus attempts to use the dma-iommu ops on an\nidentity domain, causing an oops:\n\n  # echo 0000:00:05.0 \u003e /sys/sys/bus/pci/drivers/e1000e/unbind\n  # echo identity \u003e /sys/bus/pci/devices/0000:00:05.0/iommu_group/type\n  # echo 0000:00:05.0 \u003e /sys/sys/bus/pci/drivers/e1000e/bind\n   ...\n  BUG: kernel NULL pointer dereference, address: 0000000000000028\n   ...\n   Call Trace:\n    iommu_dma_alloc\n    e1000e_setup_tx_resources\n    e1000e_open\n\nSince iommu_change_dev_def_domain() calls probe_finalize() again, clear\nthe dma_ops there like Vt-d does.","modified":"2026-03-14T14:59:04.726690Z","published":"2024-03-25T09:15:08.740Z","references":[{"type":"FIX","url":"https://git.kernel.org/stable/c/d6177a6556f853785867e2ec6d5b7f4906f0d809"},{"type":"FIX","url":"https://git.kernel.org/stable/c/f3f2cf46291a693eab21adb94171b0128c2a9ec1"}],"affected":[{"database_specific":{"unresolved_ranges":[{"events":[{"introduced":"5.11"},{"fixed":"5.12.9"}]},{"events":[{"introduced":"0"},{"last_affected":"5.13-rc1"}]},{"events":[{"introduced":"0"},{"last_affected":"5.13-rc2"}]},{"events":[{"introduced":"0"},{"last_affected":"5.13-rc3"}]}],"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-47140.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}