CVE-2021-46919: 
Linux Kernel vulnerability analysis and mitigation

A flaw was found in the Linux Kernel where the WQ (Work Queue) size can only be changed when the device is disabled. The vulnerability (CVE-2021-46919) exists because the current code allows changes when the device is enabled but WQ is disabled, instead of properly detecting the device state (Red Hat Portal).

The vulnerability affects the Linux Kernel's DMA engine IDXD driver. The issue stems from an incorrect permission state check in the WQ size store functionality. The code was checking the WQ state (wq->state != IDXD_WQ_DISABLED) instead of the device state (idxd->state == IDXD_DEV_ENABLED), which could lead to improper configuration changes (Kernel Commit).

The vulnerability has been assessed as having a Low impact. According to Red Hat's CVSS v3 scoring, it received a base score of 0, indicating minimal direct security impact (Red Hat Portal).

The issue has been fixed in the Linux kernel through a patch that changes the permission check to properly detect the device state instead of the WQ state. The fix was implemented through commit 0fff71c5a311e1264988179f7dcc217fda15fadd (Kernel Commit).