On Sun, Nov 05, 2000 at 12:28:55PM +1100, Andrew Morton wrote: > Andi Kleen wrote: > > > > On Sat, Nov 04, 2000 at 12:07:34PM -0500, Jeff Garzik wrote: > > > Andi Kleen wrote: > > > > All the MOD_INC/DEC_USE_COUNT are done inside the modules themselves. There > > > > is nothing that would a driver prevent from being unloaded on a different > > > > CPU while it is already executing in ->open but has not yet executed the add > > > > yet or after it has executed the _DEC but it is still running in module code > > > > Normally the windows are pretty small, but very long running interrupt > > > > on one CPU hitting exactly in the wrong moment can change that. > > > > > > Module unload calls unregister_netdev, which grabs rtnl_lock. > > > dev->open runs under rtnl_lock. > > > > > > Given this, how can the driver be unloaded if dev->open is running? > > > > It does not help, because when the semaphore synchronizes it is already > > too late -- free_module already did the zero module count check and > > nothing is going to stop it from unloading. > > aaarrrggh!!! A simple fix at least for this case would be a recheck of module count after free_module() executed the cleanup function. -Andi - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org
