Messages in this thread | | | Date | Mon, 24 Aug 2009 12:13:47 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH] tracing/profile: Fix profile_disable vs module_unload |
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On Mon, 24 Aug 2009, Peter Zijlstra wrote: > > > > > > > > > > > > > > > Hrmm, feel fragile, why don't we check if all a modules tracepoints are > > > > > unused on unload? > > > > > > > > > > > > > I don't think it's fragile. We are profiling via a module's > > > > tracepoint, so we should pin the module, via module_get(). > > > > If event->profile_enable() has been calld, we should make > > > > sure it's profile_disable() will be called. > > > > > > What I call fragile is that everyone registering a tracepoint > > > callback will now apparently need to worry about modules, _that_ > > > is fragile. > > > > > > Either make module unload look at tracepoint users, or place the > > > try_get_module() in the registration hooks so that regular users > > > don't need to worry about it. > > > > The bug found by Li needs to be fixed obviously. > > > > I tend to agree with you that this does not appear to be the best > > place to do it: so you suggest to implicitly increase the module > > refcount on callback registr instead? (and releasing it when > > unregistering) > > > > Same end result, slightly cleaner place to bump the refcount. > > Yes, because the user of tracepoints should never need to care about > modules.
I also agree with Peter on this.
-- Steve
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