On Mon, 14 May 2018 12:13:22 +0900 Namhyung Kim <namhy...@kernel.org> wrote:
> On Fri, May 11, 2018 at 03:49:33PM -0400, Steven Rostedt wrote: > > From: "Steven Rostedt (VMware)" <rost...@goodmis.org> > > > > Allow writing to the trace_markers file initiate triggers defined in > > tracefs/ftrace/print/trigger file. This will allow of user space to trigger > > the same type of triggers (including histograms) that the trace events use. > > > > Cc: Tom Zanussi <tom.zanu...@linux.intel.com> > > Cc: Clark Williams <willi...@redhat.com> > > Cc: Karim Yaghmour <karim.yaghm...@opersys.com> > > Cc: Brendan Gregg <bgr...@netflix.com> > > Suggested-by: Joel Fernandes <joe...@google.com> > > Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> > > --- > > [SNIP] > > diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h > > index e3a658bac10f..de3fce14cd00 100644 > > --- a/kernel/trace/trace_entries.h > > +++ b/kernel/trace/trace_entries.h > > @@ -230,7 +230,7 @@ FTRACE_ENTRY(bprint, bprint_entry, > > FILTER_OTHER > > ); > > > > -FTRACE_ENTRY(print, print_entry, > > +FTRACE_ENTRY_REG(print, print_entry, > > > > TRACE_PRINT, > > > > @@ -242,7 +242,9 @@ FTRACE_ENTRY(print, print_entry, > > F_printk("%ps: %s", > > (void *)__entry->ip, __entry->buf), > > > > - FILTER_OTHER > > + FILTER_OTHER, > > + > > + ftrace_event_register > > I wonder this is still needed since you added __find_event_file() > which ignores the reg field. Maybe I'm missing something.. No, that's not the reason for it. The reason is due to the event_trigger_callback() function. I'll update the changelog to specify this. We have something like: # echo snapshot > events/ftrace/print/trigger Which will do: event_trigger_write() { event_trigger_regex_write() { trigger_process_regex() { for p in trigger_commands { p->func(); /* trigger_snapshot_cmd->func */ event_trigger_callback() { cmd_ops->reg() /* register_trigger() */ { trace_event_trigger_enable_disable() { trace_event_enable_disable() { call->class->reg(); Without this patch, we jump to NULL and BOOM! > > Anyway it looks whitespace damaged. > Thanks, I'll fix it up. -- Steve