On Fri, Apr 25, 2014 at 09:54:33AM -0400, Alan Stern wrote: > On Fri, 25 Apr 2014, Li Zhong wrote: > > > > I don't get why try_module_get() matters here. We can't call into > > > ->store if the object at hand is already destroyed and the underlying > > > module can't go away if the target device is still alive. > > > try_module_get() doesn't actually protect the object. Why does that > > > matter? This is self removal, right? Can you please take a look at > > > kernfs_remove_self()? > > > > This is about one process writing something to driver attributes, and > > one process trying to unload this driver. > > > > I think try_module_get() could detect whether the driver is being > > unloaded, and if not, prevent it from being unloaded, so it could > > protect the object here by not allow the driver to be unloaded. > > That isn't how try_module_get() works. If the module is being > unloaded, try_module_get() simply fails. It does not prevent the > module from being unloaded -- that's why its name begins with "try". Well, to be fair, if the try_module_get() *succeeds* it will prevent the module from being unloaded (and otherwise the sysfs operation bails out). Johan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
