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SubjectRe: [PATCH v2 01/12] tracing/uprobes: Add busy check when cleanup all uprobes
On Tue, 4 Dec 2018 12:43:33 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Mon, 5 Nov 2018 18:00:15 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > Add a busy check loop in cleanup_all_probes() before
> > trying to remove all events in uprobe_events as same as
> > kprobe_events does.
> >
> > Without this change, writing null to uprobe_events will
> > try to remove events but if one of them is enabled, it
> > stopped there but some of events are already cleared.
> >
> > With this change, writing null to uprobe_events make
> > sure all events are not enabled before removing events.
> > So, it clears all events, or return an error (-EBUSY)
> > with keeping all events.
> >
>
> Hmm, should this patch be marked as stable?

Hmm, OK, let this go to stable. Since anyway, this will cause
a wired result on uprobe_events from user point of view.

Thank you!

>
> -- Steve
>
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > ---
> > kernel/trace/trace_uprobe.c | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
> > index 31ea48eceda1..b708e4ff7ea7 100644
> > --- a/kernel/trace/trace_uprobe.c
> > +++ b/kernel/trace/trace_uprobe.c
> > @@ -587,12 +587,19 @@ static int cleanup_all_probes(void)
> > int ret = 0;
> >
> > mutex_lock(&uprobe_lock);
> > + /* Ensure no probe is in use. */
> > + list_for_each_entry(tu, &uprobe_list, list)
> > + if (trace_probe_is_enabled(&tu->tp)) {
> > + ret = -EBUSY;
> > + goto end;
> > + }
> > while (!list_empty(&uprobe_list)) {
> > tu = list_entry(uprobe_list.next, struct trace_uprobe, list);
> > ret = unregister_trace_uprobe(tu);
> > if (ret)
> > break;
> > }
> > +end:
> > mutex_unlock(&uprobe_lock);
> > return ret;
> > }
>


--
Masami Hiramatsu <mhiramat@kernel.org>

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