On Wed, Jul 16, 2014 at 08:57:38PM +0530, Chetan Nanda wrote: > > > > On Wed, Jul 16, 2014 at 8:49 PM, Chetan Nanda <chetannanda@xxxxxxxxx> wrote: > > > > On Wed, Jul 16, 2014 at 6:39 PM, John de la Garza <john@xxxxxxxxx> wrote: > > On Wed, Jul 16, 2014 at 04:00:18PM +0530, Chetan Nanda wrote: > > A depends on B, so B is automatically loaded when A is loaded. > > B module is also directly being used by the user side code via misc > > interface. > >. > > Now when I am unloading module A, via "modprobe -r A" it is also > unloading > > the module B which is being used by the application and resulting in > the > > kernel crash. > > You said that A depends on B, right? Why do you have A dependng on B? > If it A needs to have B then it makes sense that you can not remove A > while > B is in use. If A doesn't need B, why not remove the dependency. > > > A is calling few APIs defined by B. > > But why when user space application is already using module B. (it has already > open its device fd) kernel allows to remove it. > > I tried with doing try_module_get() in the module's open function, it prevent > module B unloading but cause thread doing modprobe -r to hang > Is there any other way to mark module as busy when being used by user > application? Never use try_module_get(), that is racy. What is the user/kernel interface you are using, and why doesn't it automatically increase the module count when userspace opens the interface? It should all be done in a way that your module doesn't need to do anything special. thanks, greg k-h _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
