linux — security advisory
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->dma_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 > /sys/sys/bus/pci/drivers/e1000e/unbind # echo identity > /sys/bus/pci/devices/0000:00:05.0/iommu_group/type # echo 0000:00:05.0 > /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.
- Products
- linux
- Affected versions
- Not specified
- Fixed versions
- 5.14.6-1
- CVEs
- CVE-2021-47140
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 01:11 UTC · Revision 1
Source evidence
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->dma_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 > /sys/sys/bus/pci/drivers/e1000e/unbind # echo identity > /sys/bus/pci/devices/0000:00:05.0/iommu_group/type # echo 0000:00:05.0 > /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.
osv:DEBIAN-CVE-2021-47140
linux
Fixed versions: 5.14.6-1
linux
Fixed versions: 5.14.6-1
linux
Fixed versions: 5.14.6-1
Complete source record
{
"id": "6db4726322d5357bd3ce7b7723d130505e48e91bd1cb62c9585ad56bc972cef6",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2021-47140",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2021-47140",
"summary": "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->dma_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 > /sys/sys/bus/pci/drivers/e1000e/unbind # echo identity > /sys/bus/pci/devices/0000:00:05.0/iommu_group/type # echo 0000:00:05.0 > /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.",
"evidence": "osv:DEBIAN-CVE-2021-47140",
"products": [
{
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"severity": "medium",
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"metrics": [
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"package": {
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"package": {
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"database_specific": {
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"ecosystem_specific": {
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}
}
],
"modified": "2026-10-23T18:04:18.514893101Z",
"provider": "osv",
"upstream": [
"CVE-2021-47140"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2021-47140"
]
},
"related_cves": [
{
"value": "CVE-2021-47140",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 423286,
"published_at": "2024-03-25T09:15:08.74+00:00"
}