On (12/04/16 11:28), Greg KH wrote: > On Sun, Dec 04, 2016 at 11:35:15AM +0900, Sergey Senozhatsky wrote: [..] > Why can't a normal user read the attribute? Does a read actually modify > something? yes, it does. reading from a hot_add file creates a new zram device and returns a new device's device_id. not initialized device (so it does not eat the memory for handle table, etc.), but with its own set of sysfs attrs, etc. which consumes memory after all. so a 'normal' user, doing a simple read from a hot_add file in a loop just for fun, can create a lot of devices and, quite likely, cause some troubles (as reported by Steven Allen). -ss -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html