From this webpage screenshot, we can extract the following key information about the vulnerability: 1. Vulnerability Description: - When the BHI (Branch History Invalidation) mechanism is enabled, if SYSENTER is invoked with the TF (Task Flag) bit set, the function will use and call , causing a #DB (Debug) exception to be triggered by the processor before the TF flag is cleared. 2. Reproduction Steps: - The issue can be reproduced by following these steps: 1. Write a C program named containing the following code: 2. Compile the program using gcc. 3. Run the compiled binary. - The result will be a Segmentation fault (core dump). 3. Kernel Log: - The kernel log displays error messages including CPU number, PID, and error location. 4. Fix: - The fix involves adding the operation within the function to ensure it is executed before the TF flag is cleared. 5. Patch Information: - This patch fixes the vulnerability introduced by commit 7390db8aea0d ("x86/bhi: Add support for clearing branch history at syscall entry"). - The patch was reported by Suman Maity, signed by Alexandre Chartre and Borislav Petkov (AMD), reviewed by Andrew Cooper and Pawan Gupta, and signed by Josh Poinboeuf and Sasha Levin. 6. Code Changes: - The change was made in the file , adding the instruction. This information indicates that the vulnerability relates to the handling of the TF flag during SYSENTER calls when the BHI mechanism is active. The fix ensures that is executed prior to clearing the TF flag.