In the Linux kernel, the following vulnerability has been resolved:
iommu/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init
A user VINTF is torn down by tegra241_cmdqv_deinit_vintf(), which runs from
the destroy callback and from the init-failure unwind in the alloc handler.
It clears the cmdqv->vintfs[] slot and lets the iommufd core free it, but
nothing serializes that against the error interrupt: tegra241_cmdqv_isr()
reads cmdqv->vintfs[idx] and dereferences the vintf. A concurrent error can
make the ISR read a slot mid-clear (a NULL deref) or use a vintf which is
about to be freed (a use-after-free).
deinit_vintf() also returns idx to the IDA before clearing the slot, so a
concurrent create that reuses idx can publish its new vintf into the slot,
only for this teardown to erase it again with the stale NULL store.
On the other end, tegra241_cmdqv_init_vintf() publishes a new vintf with a
plain store to the cmdqv->vintfs[] slot, and the ISR dereferences fields of
a published vintf such as vintf->base. A plain store gives no ordering on a
weakly-ordered CPU, and a stale VINTF_ERR_MAP bit on a reused idx can make
the ISR pick a vintf the moment it is published, before its fields are set
or tegra241_vintf_hw_init() runs.
The cmdqv->vintfs[0] slot stays NULL until tegra241_cmdqv_init_structures()
first creates VINTF0, so the slot 0 read needs the same NULL check.
Publish every slot with an smp_store_release(), and read each slot in the
ISR with an smp_load_acquire() under a NULL check, so the ISR always sees
a fully built vintf or NULL. Also make deinit_vintf() clear the slot, and
synchronize_irq() prior to returning idx to the IDA, so no vintf is freed
under a running handler and no reused idx is clobbered.
iommu/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init
A user VINTF is torn down by tegra241_cmdqv_deinit_vintf(), which runs from
the destroy callback and from the init-failure unwind in the alloc handler.
It clears the cmdqv->vintfs[] slot and lets the iommufd core free it, but
nothing serializes that against the error interrupt: tegra241_cmdqv_isr()
reads cmdqv->vintfs[idx] and dereferences the vintf. A concurrent error can
make the ISR read a slot mid-clear (a NULL deref) or use a vintf which is
about to be freed (a use-after-free).
deinit_vintf() also returns idx to the IDA before clearing the slot, so a
concurrent create that reuses idx can publish its new vintf into the slot,
only for this teardown to erase it again with the stale NULL store.
On the other end, tegra241_cmdqv_init_vintf() publishes a new vintf with a
plain store to the cmdqv->vintfs[] slot, and the ISR dereferences fields of
a published vintf such as vintf->base. A plain store gives no ordering on a
weakly-ordered CPU, and a stale VINTF_ERR_MAP bit on a reused idx can make
the ISR pick a vintf the moment it is published, before its fields are set
or tegra241_vintf_hw_init() runs.
The cmdqv->vintfs[0] slot stays NULL until tegra241_cmdqv_init_structures()
first creates VINTF0, so the slot 0 read needs the same NULL check.
Publish every slot with an smp_store_release(), and read each slot in the
ISR with an smp_load_acquire() under a NULL check, so the ISR always sees
a fully built vintf or NULL. Also make deinit_vintf() clear the slot, and
synchronize_irq() prior to returning idx to the IDA, so no vintf is freed
under a running handler and no reused idx is clobbered.
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/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init A user VINTF is torn down by tegra241_cmdqv_deinit_vintf(), which runs from the destroy callback and from the init-failure unwind in the alloc handler. It clears the cmdqv->vintfs[] slot and lets the iommufd core free it, but nothing serializes that against the error interrupt: tegra241_cmdqv_isr() reads cmdqv->vintfs[idx] and dereferences the vintf. A concurrent error can make the ISR read a slot mid-clear (a NULL deref) or use a vintf which is about to be freed (a use-after-free). deinit_vintf() also returns idx to the IDA before clearing the slot, so a concurrent create that reuses idx can publish its new vintf into the slot, only for this teardown to erase it again with the stale NULL store. On the other end, tegra241_cmdqv_init_vintf() publishes a new vintf with a plain store to the cmdqv->vintfs[] slot, and the ISR dereferences fields of a published vintf such as vintf->base. A plain store gives no ordering on a weakly-ordered CPU, and a stale VINTF_ERR_MAP bit on a reused idx can make the ISR pick a vintf the moment it is published, before its fields are set or tegra241_vintf_hw_init() runs. The cmdqv->vintfs[0] slot stays NULL until tegra241_cmdqv_init_structures() first creates VINTF0, so the slot 0 read needs the same NULL check. Publish every slot with an smp_store_release(), and read each slot in the ISR with an smp_load_acquire() under a NULL check, so the ISR always sees a fully built vintf or NULL. Also make deinit_vintf() clear the slot, and synchronize_irq() prior to returning idx to the IDA, so no vintf is freed under a running handler and no reused idx is clobbered. | |
| Title | iommu/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init | |
| 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: 2026-09-17T16:09:50.442Z
Reserved: 2026-09-11T19:38:34.814Z
Link: CVE-2026-90429
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-17T17:17:47.850
Modified: 2026-09-17T17:17:47.850
Link: CVE-2026-90429
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.