Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
s390/entry: Scrub r12 register on kernel entry
Before commit f33f2d4c7c80 (“s390/bp: remove TIF_ISOLATE_BP”), all entry handlers loaded r12 with the current task pointer (lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That commit removed TIF_ISOLATE_BP, dropping both the branch prediction macros and the r12 load, but did not add r12 to the register clearing sequence.
Add the missing xgr %r12,%r12 to make the register scrub consistent across all entry points.
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , RHEL 7 ELS , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 4.18.0 (+6 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| Debian 13 | Planned | — |
| Ubuntu 24.04 | Planned | — |