CVE-2026-45945— iommu/vt-d: Fix race condition during PASID entry replacement

iommu/vt-d: Fix race condition during PASID entry replacement

In the Linux kernel, the following vulnerability has been resolved: iommu/vt-d: Fix race condition during PASID entry replacement The Intel VT-d PASID table entry is 512 bits (64 bytes). When replacing an active PASID entry (e.g., during domain replacement), the current implementation calculates a new entry on the stack and copies it to the table using a single structure assignment. struct pasid_entry *pte, new_pte; pte = intel_pasid_get_entry(dev, pasid); pasid_pte_config_first_level(iommu, &new_pte, ...); *pte = new_pte; Because the hardware may fetch the 512-bit PASID entry in multiple 128-bit chunks, updating the entire entry while it is active (Present bit set) risks a "torn" read. In this scenario, the IOMMU hardware could observe an inconsistent state — partially new data and partially old data — leading to unpredictable behavior or spurious faults. Fix this by removing the unsafe "replace" helpers and following the "clear-then-update" flow, which ensures the Present bit is cleared and the required invalidation handshake is completed before the new configuration is applied.

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

N/A

Linux kernel 安全漏洞

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于iommu/vt-d驱动在PASID条目替换时存在竞争条件，可能导致硬件读取不一致状态并引发不可预测行为或虚假故障。

N/A

N/A