Suman Maity

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** The issue is related to the x86/bhi mitigation in the Linux kernel. When BHI mitigation is enabled and SYSENTER is invoked with the TF flag set, the `entry SYSENTER compat()` function uses `CLEAR BRANCH HISTORY` and calls `clear bhb loop()` before the TF flag is cleared. This causes the #DB handler (`exc debug kernel()`) to issue a warning because single-step is used outside the `entry SYSENTER compat()` function. The problem can be reproduced with a specific sequence of assembly code instructions. The kernel log shows a warning and a call trace indicating the issue. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.