Messages in this thread | | | Date | Thu, 1 Aug 2013 16:46:22 +0200 | From | Oleg Nesterov <> | Subject | Re: [RFC][PATCH 3/4] tracing/kprobes: Fail to unregister if probe event files are open |
| |
On 08/01, Steven Rostedt wrote: > > On Thu, 2013-08-01 at 16:33 +0200, Oleg Nesterov wrote: > > On 08/01, Steven Rostedt wrote: > > > > > > On Thu, 2013-08-01 at 15:34 +0200, Oleg Nesterov wrote: > > > > > > > > > > __unregister_trace_probe(tp); > > > > > list_del(&tp->list) > > > > > unregister_probe_event(tp) <-- fails! > > > > > free_trace_probe(tp) > > > > > > > > Yes. But again, this doesn't explain why unregister_probe_event()-> > > > > __trace_remove_event_call() can't simply proceed and > > > > do ftrace_event_enable_disable() + remove_event_from_tracers(). > > > > > > The problem is with the soft disable. > > > > Exactly! This is another (also unlikely) race we need to prevent. > > > > Is there a race even with these patches?
Sorry for confusion,
> I don't see one.
Neither me, but only with these changes.
I meant that this is another reason why trace_remove_event_call() should fail and the caller should obviously abort in this case.
> Or are you just saying that these patches fix that case too?
Yes, sorry.
Oleg.
| |