CVE-2025-71119: powerpc/kexec: Enable SMT before waking offline CPUs
In the Linux kernel, the following vulnerability has been resolved:
powerpc/kexec: Enable SMT before waking offline CPUs
If SMT is disabled or a partial SMT state is enabled, when a new kernel image is loaded for kexec, on reboot the following warning is observed:
kexec: Waking offline cpu 228. WARNING: CPU: 0 PID: 9062 at arch/powerpc/kexec/core64.c:223 kexecpreparecpus+0x1b0/0x1bc [snip] NIP kexecpreparecpus+0x1b0/0x1bc LR kexecpreparecpus+0x1a0/0x1bc Call Trace: kexecpreparecpus+0x1a0/0x1bc (unreliable) defaultmachinekexec+0x160/0x19c machinekexec+0x80/0x88 kernelkexec+0xd0/0x118 dosysreboot+0x210/0x2c4 systemcallexception+0x124/0x320 systemcallvectoredcommon+0x15c/0x2ec
This occurs as addcpu() fails due to cpubootable() returning false for CPUs that fail the cpusmtthreadallowed() check or non primary threads if SMT is disabled.
Fix the issue by enabling SMT and resetting the number of SMT threads to the number of threads per core, before attempting to wake up all present CPUs.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2025-71119?
CVE-2025-71119 has not been assigned a CVSS score yet, but it is critical due to its impact on system stability and performance.
How do I fix CVE-2025-71119?
To fix CVE-2025-71119, you should upgrade to the latest version of the Linux kernel where the vulnerability has been addressed.
What systems are affected by CVE-2025-71119?
CVE-2025-71119 affects Linux kernel versions that utilize kexec on powerpc architectures with SMT configuration.
What happens if I do not address CVE-2025-71119?
If CVE-2025-71119 is not addressed, it could lead to system crashes or performance degradation during kernel reboots.
Is there a workaround for CVE-2025-71119?
Currently, there is no widely recognized workaround for CVE-2025-71119 besides applying the kernel patch.