hi, i dont know wheather i'm asking any meaningful querry, one thing we can sleep by means of kernel thread,which executes in kernel space and still can be put to sleep,who will wake up this kernel thread scheduler?is scheduler involved in this, and is there any other way for waiting in kernel space,i think its not. its simple if i put my module into blocking call it will hang my system! prasanna __________________________________ Do you Yahoo!? Yahoo! Domains ? Claim yours for only $14.70/year http://smallbusiness.promotions.yahoo.com/offer -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/