side effects of calling interruptible_sleep_on_timeout()

Hi, A switch driver is causing soft lockup on Montavista Linux Kernel 2.6.10 system. While browsing through the code of the driver. I came across a snippet where after disabling the interrupts a call is made to interruptible_sleep_on_timeout(). The code snippet is like cli(); init_waitqueue_head(&queue); interruptible_sleep_on_timeout(&queue, USEC_TO_JIFFIES(usec)); thread_check_signals(); sti(); I need to know the side effect of this sort of code, can it be responsible for the softlockup of the system ? Its a PowerPC based system. Regards, Devendra