On Mon, 9 Dec 2002, Edward Gerhold wrote: > > > Jose Luis Alarcon wrote: > > > Hi, kernel developers. > > > > I has a big surprise when, adding at the beginning of init_module() > > the macro MOD_INC_USE_COUNT, for have a module use counter. My program > > get compile well and insmod work too. > > > > But the surprise was when i did rmmod, cos the output said: > > > > FATAL: the module is in use > > > > I did lsmod, and i got that my module was used by [unsafe]. > > > > Any kernel programmer with experience knows why happen this?. > > > > IMHO a use counter is a very few dangerous thing. So i was trying with. > > > > Thanks you, very much, in advance. > > > > Regards. > > > > Jose. > > > > I don't know why this happens, > but can it be, that you forgot MOD_DEC_USE_COUNT in your cleanup routine ? > > bye > Edward > Basically, adding MOD_INC_USE_COUNT in init_module() is not a right idea, usage counts are used to keep track of current users of the module & the system doesn't allow removing the module if usage count is non-zero. In your case, - You have incremented usage count to 1 during init_module() - When you run rmmod, it calls delete_module() system call which checks for the usage count, if it is zero, then ONLY it calls the cleanup routine of corresponding module, if it is non-zero, system call returns EBUSY error thinking someone is using this module, so even if you do add MOD_DEC_USE_COUNT in clenup routine, it's of no use. For more info. look for implementation of sys_delete_module(). bye, Madhu -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
