A 'soft lockup' is defined as a bug that causes the kernel to loop in kernel mode for more than 20 seconds without giving other tasks a chance to run.
The watchdog daemon will send an non-maskable interrupt (NMI) to all CPUs in the system who, in turn, print the stack traces of their currently running tasks.
Some kernels allow you to adjust the soft lockup threshold by running the command:
echo time > /proc/sys/kernel/softlockup_thresh
Where time is the number of seconds after which a soft lockup is reported. The default is generally 10 or 20 seconds. So you can change that to up to a maximum of 60 seconds - I would try 30 and see what happens - so the command would look like this -
echo 30 > /proc/sys/kernel/watchdog_thresh