(2013/07/18 23:51), Oleg Nesterov wrote: > On 07/18, Masami Hiramatsu wrote: >> >> (2013/07/17 23:51), Oleg Nesterov wrote: >>> Well, perhaps you are right... But this TRACE_EVENT_FL_REF_MASK code >>> is new too, it is not that we only need a small fixlets to finish it. >> >> Would you mean that TRACE_EVENT_FL_REF_MASK may also have some problems? > > It was you who initially pointed that it does have problems ;) > > And, _afaics_ your patch which tries to fix this problem is not > exactly correct.
Hm, > It removes trace_array_get/put from tracing_open_generic_file() and > tracing_release_generic_file(). This assumes that "call->flags++" is > enough, but it is not. No, it replaces trace_array_get/put with ftrace_event_file_get/put which calls trace_array_get/put inside. (Just one point, previous ftrace_event_file_get has a racy point when it does tr->ref++, it should be fixed.) > Yes, the next patch adds the "flags & TRACE_EVENT_FL_REF_MASK" check > into trace_remove_event_call() path. But this is still racy wrt > instance_delete() unless I missed something. > > IOW, I believe that either .open() should do trace_array_get(), or > __trace_remove_event_dirs() needs another for-each-file loop which > checks file->call->flags & TRACE_EVENT_FL_REF_MASK. Agreed :) >>> So I think that it makes sense to discuss the alternatives before we >>> decide what exactly we should do. >> >> Your approach is also interesting for me, indeed. However, it is so >> different from current one. I think you should clarify what bug you >> would like to solve and how. > > The same bugs which Steven's 1/4 tries to solve ;) OK, let me confirm that, would you mean we still need 2/4 - 4/4? Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- 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/
