In the Linux kernel, the following vulnerability has been resolved:
iommu/dma: Restore locking around msi_page_list
Unlike a group's default domain, which is always freshly allocated
and privately owned (iommu_group_alloc_default_domain()), VFIO type1's
legacy container merges any newly attached group into an existing
domain whenever their iommu_ops and cache-coherency enforcement match.
iommu_dma_get_msi_page() only asserts the caller's own group mutex is
held (iommu_group_mutex_assert()). On an IOMMU that publishes
IOMMU_RESV_SW_MSI, e.g. ARM SMMU, a VM with two such devices assigned
through the legacy container can have their guest drivers probe and
allocate MSIs in parallel; each host-side VFIO_DEVICE_SET_IRQS lands
on a different device fd and group mutex, but both devices' domains
are the same merged domain, so both can enter
iommu_dma_get_msi_page() concurrently and corrupt msi_page_list.
commit 288683c92b1a ("iommu: Make iommu_dma_prepare_msi() into a
generic operation") dropped the prior msi_prepare_lock on the
reasoning that "each iommu_domain is unique to a group," which holds
for default domains but not this VFIO type1 case. Restore the static
lock, since it's only guarding a corner case and will likely never
be contended.
iommufd avoids the equivalent problem by having its own callers
(iommufd_sw_map_msi()) take a ctx-wide sw_msi_lock before ever
reaching the shared list. VFIO type1 can't mirror that since it
dispatches to iommu_dma_sw_msi() which is outside VFIO's jurisdiction.
iommu/dma: Restore locking around msi_page_list
Unlike a group's default domain, which is always freshly allocated
and privately owned (iommu_group_alloc_default_domain()), VFIO type1's
legacy container merges any newly attached group into an existing
domain whenever their iommu_ops and cache-coherency enforcement match.
iommu_dma_get_msi_page() only asserts the caller's own group mutex is
held (iommu_group_mutex_assert()). On an IOMMU that publishes
IOMMU_RESV_SW_MSI, e.g. ARM SMMU, a VM with two such devices assigned
through the legacy container can have their guest drivers probe and
allocate MSIs in parallel; each host-side VFIO_DEVICE_SET_IRQS lands
on a different device fd and group mutex, but both devices' domains
are the same merged domain, so both can enter
iommu_dma_get_msi_page() concurrently and corrupt msi_page_list.
commit 288683c92b1a ("iommu: Make iommu_dma_prepare_msi() into a
generic operation") dropped the prior msi_prepare_lock on the
reasoning that "each iommu_domain is unique to a group," which holds
for default domains but not this VFIO type1 case. Restore the static
lock, since it's only guarding a corner case and will likely never
be contended.
iommufd avoids the equivalent problem by having its own callers
(iommufd_sw_map_msi()) take a ctx-wide sw_msi_lock before ever
reaching the shared list. VFIO type1 can't mirror that since it
dispatches to iommu_dma_sw_msi() which is outside VFIO's jurisdiction.
Metrics
Affected Vendors & Products
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Thu, 17 Sep 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: iommu/dma: Restore locking around msi_page_list Unlike a group's default domain, which is always freshly allocated and privately owned (iommu_group_alloc_default_domain()), VFIO type1's legacy container merges any newly attached group into an existing domain whenever their iommu_ops and cache-coherency enforcement match. iommu_dma_get_msi_page() only asserts the caller's own group mutex is held (iommu_group_mutex_assert()). On an IOMMU that publishes IOMMU_RESV_SW_MSI, e.g. ARM SMMU, a VM with two such devices assigned through the legacy container can have their guest drivers probe and allocate MSIs in parallel; each host-side VFIO_DEVICE_SET_IRQS lands on a different device fd and group mutex, but both devices' domains are the same merged domain, so both can enter iommu_dma_get_msi_page() concurrently and corrupt msi_page_list. commit 288683c92b1a ("iommu: Make iommu_dma_prepare_msi() into a generic operation") dropped the prior msi_prepare_lock on the reasoning that "each iommu_domain is unique to a group," which holds for default domains but not this VFIO type1 case. Restore the static lock, since it's only guarding a corner case and will likely never be contended. iommufd avoids the equivalent problem by having its own callers (iommufd_sw_map_msi()) take a ctx-wide sw_msi_lock before ever reaching the shared list. VFIO type1 can't mirror that since it dispatches to iommu_dma_sw_msi() which is outside VFIO's jurisdiction. | |
| Title | iommu/dma: Restore locking around msi_page_list | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-17T16:07:47.121Z
Reserved: 2026-09-11T19:38:34.795Z
Link: CVE-2026-90244
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:20.400
Modified: 2026-09-17T17:17:20.400
Link: CVE-2026-90244
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.