Hi, Roy Smith wrote: > where am I wrong here ? You're wrong in the fact that a kernel module _doesn't_ run: it's not an active entity like a process or a thread. The code of a kernel module gets executed only in the context of an active entity: either a kernel thread, a user-space process, or an interrupt handler. The locking to provide will depend on what does the module, and how it is used by the active entity using it (through a syscall, through a /proc interface, through a Netlink socket, or something else). If you don't provide details about what you're trying to do, nobody will be able to help you. And again, the locking problem appears also in uni-processor systems, not only on SMP-systems. Sincerly, Thomas -- Thomas Petazzoni thomas.petazzoni@xxxxxxxx -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/