Gustavo Romero

**Name of the Vulnerable Software and Affected Versions** Linux kernel versions prior to 4.18 **Description** The issue is caused by a conflicting use of HSTATE HOST R1 to store r1 state in kvmppc hv entry plus in kvmppc {save,restore} tm, leading to a stack corruption. An attacker with the ability to run code in kernel space of a guest VM can cause the host kernel to panic. The vulnerability was introduced by two commits that landed in versions 4.8 and 4.17. **Recommendations** For Linux kernel versions prior to 4.18, update to version 4.18 or later to resolve the issue. As a temporary workaround, consider disabling the `kvmppc save tm()` and `kvmppc restore tm()` functions until a patch is available. Restrict access to the vulnerable `kvmppc hv entry` and `kvmppc {save,restore} tm` functions to minimize the risk of exploitation.