Messages in this thread | | | Date | Fri, 28 Jun 2013 20:43:25 +0200 | From | Oleg Nesterov <> | Subject | Re: [PATCH] tracing/kprobe: Recover old array if fails to enable kprobe |
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On 06/28, Steven Rostedt wrote: > > On Fri, 2013-06-28 at 16:27 +0200, Oleg Nesterov wrote: > > > > Ah, but this conflicts with the other changes I sent. They have > > your acks, and iiuc Steven is going to apply them. > > I'll see if I can solve any conflicts. I need to get my -rt versions out > and start on the new 3.6 stable today. Then after that, I plan on going > though and getting all the tracing patches settled.
Thanks!
> > Besides, this fix is not complete afaics, we should also clear > > TP_FLAG_TRACE/PROFILE if __enable_trace_probe() fails.
Yes.
And I forgot to mention, until we fix the races we discuss in another thread, this WARN_ON() doesn't look right. So perhaps it would be really better to delay this change a bit.
Oleg.
> > Perhaps you can do this later, on top of the pending changes? > > > > Or. Given that this patch assumes that enable_kprobe() must succed, > > can't we make a minimal change for now? > > > > ------------------------------------------------------------------------------- > > [PATCH] tracing/kprobe: WARN() if enable_kprobe() fails. > > > > enable_trace_probe() doesn't recover tp->files/flags if enable_kprobe() > > fails, this looks confusing. > > > > However, enable_kprobe() must not fail at this time except for unknown > > bug or changing the implementation of enable_kprobe(), because usual > > failure cases (not registered or gone) are already filtered. > > > > So this patch simply adds WARN_ON(ret) to document this fact, even if > > it makes sense to cleanup the logic anyway later. > > > > Reported-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> > > Signed-off-by: Oleg Nesterov <oleg@redhat.com> > > --- > > kernel/trace/trace_kprobe.c | 1 + > > 1 files changed, 1 insertions(+), 0 deletions(-) > > > > diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c > > index 5c070db..bb608b5 100644 > > --- a/kernel/trace/trace_kprobe.c > > +++ b/kernel/trace/trace_kprobe.c > > @@ -220,6 +220,7 @@ enable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file) > > ret = enable_kretprobe(&tp->rp); > > else > > ret = enable_kprobe(&tp->rp.kp); > > + WARN_ON(ret); > > } > > out: > > return ret; > >
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