Masami, I am not sure I understand. And please do not forget I am not familiar with this code ;)
In short: do you think that the patch I sent "can't help" or "not enough" ? If "not enough" then I fully agree. On 07/03, Masami Hiramatsu wrote: > > (2013/07/03 7:23), Oleg Nesterov wrote: > > On 07/02, Oleg Nesterov wrote: > >> > >> So please ignore modules ;) > > > > Or lets discuss the change above. > > No, I think this still doesn't ensure that we can remove dynamic > event safely. Since the event is related to several files under > events/ dir and buffer instances, someone can just stay open the > files while the event is removed and read/write it. So, for example, event_enable_write() can happily play with ftrace_event_file after unregister_trace_probe/free_trace_probe. Did you mean this? Sure, but this is another problem? And we already discussed it a bit, an application can keep the file we need to remove opened. As for event_enable_write() in particular, we can probably mark file/call as dead somewhere in trace_remove_event_call(). But I simply do not understand this code enough, I do not know what else we should do. IOW. So far _I think_ we just need the additional changes in trace_remove_event_call() if it succeeds (with the patch I sent) to prevent the races like above, but I didn't even try to think about this problem. Or I missed your point completely? Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
