CVE-2021-47400

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 5.14.0-rc4+

Description The vulnerability is related to the hns3 nic net open() function in the Linux kernel, which is not allowed to be called repeatedly. However, there is no checking for this, and when doing device reset and setup tc concurrently, there is a small opportunity to call hns3 nic net open() repeatedly, causing a kernel bug by calling napi enable() twice.

Recommendations To resolve this issue, add checking for the HNS3 NIC STATE DOWN flag and directly return when it is not set. This will prevent the repeated calling of hns3 nic net open() and subsequent kernel bug.

Note: The provided information does not specify the exact version where the fix is applied, so it is recommended to update to the latest version of the Linux kernel to ensure the issue is resolved.