hi,all In LDD2 Chapter6 "Flow of Time", it says "When running in interrupt mode" code is subject to a number of constraints, one of which is "The current pointer is not valid in interrupt mode, and cannot be used". But in the timer interrupt handler do_timer()-->update_process_times(), the "current" is explicitly referenced. Anyone explains this ? -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/