{"id":"DEBIAN-CVE-2021-47140","details":"In the Linux kernel, the following vulnerability has been resolved:  iommu/amd: Clear DMA ops when switching domain  Since commit 08a27c1c3ecf (\"iommu: Add support to change default domain of an iommu group\") a user can switch a device between IOMMU and direct DMA through sysfs. This doesn't work for AMD IOMMU at the moment because dev-\u003edma_ops is not cleared when switching from a DMA to an identity IOMMU domain. The DMA layer thus attempts to use the dma-iommu ops on an identity domain, causing an oops:    # echo 0000:00:05.0 \u003e /sys/sys/bus/pci/drivers/e1000e/unbind   # echo identity \u003e /sys/bus/pci/devices/0000:00:05.0/iommu_group/type   # echo 0000:00:05.0 \u003e /sys/sys/bus/pci/drivers/e1000e/bind    ...   BUG: kernel NULL pointer dereference, address: 0000000000000028    ...    Call Trace:     iommu_dma_alloc     e1000e_setup_tx_resources     e1000e_open  Since iommu_change_dev_def_domain() calls probe_finalize() again, clear the dma_ops there like Vt-d does.","modified":"2026-09-01T20:03:16.350557763Z","published":"2024-03-25T09:15:08.740Z","upstream":["CVE-2021-47140"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-47140"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.14.6-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47140.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.14.6-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47140.json"}},{"package":{"name":"linux","ecosystem":"Debian:14","purl":"pkg:deb/debian/linux?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.14.6-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2021-47140.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}