9.3. Spurious soft lockups in virtualized environments

The soft lockup firing on physical hosts usually represents a kernel or a hardware bug. The same phenomenon happening on guest operating systems in virtualized environments might represent a false warning.

Heavy workload on a host or high contention over some specific resource, such as memory, can cause a spurious soft lockup firing because the host might schedule out the guest CPU for a period longer than 20 seconds. When the guest CPU is again scheduled to run on the host, it experiences a time jump that triggers the due timers. The timers also include the hrtimer watchdog that can report a soft lockup on the guest CPU.

Soft lockup in a virtualized environment can be false. You must not enable the kernel parameters that trigger a system panic when a soft lockup reports to a guest CPU.