Messages in this thread | | | Date | Mon, 18 Dec 2017 18:51:43 -0500 | From | Steven Rostedt <> | Subject | Re: [PATCH 3/3] trace: print address if symbol not found |
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On Tue, 19 Dec 2017 08:16:14 +1100 "Tobin C. Harding" <me@tobin.cc> wrote:
> > > #endif /* _LINUX_KERNEL_TRACE_H */ > > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > > > index 1e1558c99d56..3e28522a76f4 100644 > > > --- a/kernel/trace/trace_events_hist.c > > > +++ b/kernel/trace/trace_events_hist.c > > > @@ -982,7 +982,7 @@ static void hist_trigger_stacktrace_print(struct seq_file *m, > > > return; > > > > > > seq_printf(m, "%*c", 1 + spaces, ' '); > > > - sprint_symbol(str, stacktrace_entries[i]); > > > + trace_sprint_symbol_addr(str, stacktrace_entries[i]); > >
> > If you have the time to give me some brief pointers on how I should go > about testing this I'd love to test it before the next version. I know > very little about ftrace.
For hitting the histogram stacktrace trigger (this code path), make sure you have CONFIG_HIST_TRIGGERS enabled. And then do:
# cd /sys/kernel/debug/tracing # echo 'hist:keys=common_pid.execname,stacktrace:vals=prev_state' > \ events/sched/sched_switch/trigger # cat events/sched/sched_switch/hist
For the "sym" part, you can do (from the same directory):
# echo 'hist:keys=call_site.sym:vals=bytes_req' > \ events/kmem/kmalloc/trigger # cat events/kmem/kmalloc/hist
And for sym-offset:
# echo 'hist:keys=call_site.sym-offset:vals=bytes_req' > \ events/kmem/kmalloc/trigger # cat events/kmem/kmalloc/hist
-- Steve
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