Hello. I'm developing a small patch in fs/*.c that needs to refer '(struct task_struct *) current'. And I want to know whether the value of 'current' is valid or not. According to 'Unreliable Guide To Hacking The Linux Kernel', there are 4 players. (1) not associated with any process, serving a hardware interrupt; (2) not associated with any process, serving a softirq, tasklet or bh; (3) running in kernel space, associated with a process; (4) running a process in user space. And also says, "value of 'current' is not NULL in interrupt context". I think it means in the state (1) or (2), I must not refer to 'current', but I can't determine the state by checking 'current' == NULL. I don't know whether functions defined in fs/*.c is called by the players (1) and (2). But if these functions could be called by (1) and (2), I need to confirm whether I can refer to 'current' or not. How can I determine the value of 'current' is valid or not (if these functions could be called by (1) and (2)) ? I want to know 'current' is valid or not even when interrupts or bottom halves are disabled outside of my patch functions, so it is not enough just checking "in_interrupt() returns 0". Regards. -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
