CVE-2026-43253 PUBLISHED

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.

• https://git.kernel.org/stable/c/f2f65b28d802a667119147444ec2ae33eebf9a58
• https://git.kernel.org/stable/c/715c263119fd1b918a9fcbd8a36ea5b604a46324
• https://git.kernel.org/stable/c/e15768e68820142077bbca402d8e902f64ade1b0
• https://git.kernel.org/stable/c/496269d12072ecb219826485bdbec70c92a8eef5
• https://git.kernel.org/stable/c/d2a0cac10597068567d336e85fa3cbdbe8ca62bf