CVE-2026-43253

iommu/amd: move wait_on_sem() out of spinlock

State: Published
Severity: 7.5 High
Published: May 6, 2026
Updated: Oct 30, 2026
Reserved: May 1, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

iommu/amd: move wait_on_sem() out of spinlock

With iommu.strict=1, the existing completion wait path can cause soft lockups under stressed environment, as wait_on_sem() busy-waits under the spinlock with interrupts disabled.

Move the completion wait in iommu_completion_wait() out of the spinlock. wait_on_sem() only polls the hardware-updated cmd_sem and does not require iommu->lock, so holding the lock during the busy wait unnecessarily increases contention and extends the time with interrupts disabled.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	Linux

Weaknesses

CWE-833 Deadlock

Affected Products

Product	Versions
LinuxLinux	4bf5beef578e46393f11eb69dda7d17a065e05ff to before 69d9339c02eddfc2a345be7220651068a3684383Affected 4bf5beef578e46393f11eb69dda7d17a065e05ff to before f2f65b28d802a667119147444ec2ae33eebf9a58Affected 4bf5beef578e46393f11eb69dda7d17a065e05ff to before 715c263119fd1b918a9fcbd8a36ea5b604a46324Affected 4bf5beef578e46393f11eb69dda7d17a065e05ff to before e15768e68820142077bbca402d8e902f64ade1b0Affected 4bf5beef578e46393f11eb69dda7d17a065e05ff to before 496269d12072ecb219826485bdbec70c92a8eef5Affected 4bf5beef578e46393f11eb69dda7d17a065e05ff to before d2a0cac10597068567d336e85fa3cbdbe8ca62bfAffected
LinuxLinux	4.9Affected before 4.9Not affected 6.1.191 through 6.1.Not affected 6.6.128 through 6.6.Not affected 6.12.75 through 6.12.Not affected 6.18.16 through 6.18.Not affected 6.19.6 through 6.19.*Not affected 7.0 and laterNot affected

Product

Versions

LinuxLinux

4bf5beef578e46393f11eb69dda7d17a065e05ff to before 69d9339c02eddfc2a345be7220651068a3684383Affected
4bf5beef578e46393f11eb69dda7d17a065e05ff to before f2f65b28d802a667119147444ec2ae33eebf9a58Affected
4bf5beef578e46393f11eb69dda7d17a065e05ff to before 715c263119fd1b918a9fcbd8a36ea5b604a46324Affected
4bf5beef578e46393f11eb69dda7d17a065e05ff to before e15768e68820142077bbca402d8e902f64ade1b0Affected
4bf5beef578e46393f11eb69dda7d17a065e05ff to before 496269d12072ecb219826485bdbec70c92a8eef5Affected
4bf5beef578e46393f11eb69dda7d17a065e05ff to before d2a0cac10597068567d336e85fa3cbdbe8ca62bfAffected

LinuxLinux

4.9Affected
before 4.9Not affected
6.1.191 through 6.1.*Not affected
6.6.128 through 6.6.*Not affected
6.12.75 through 6.12.*Not affected
6.18.16 through 6.18.*Not affected
6.19.6 through 6.19.*Not affected
7.0 and laterNot affected

References

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