On Mon, 9 Apr 2018 13:59:16 +0530
Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com> wrote:

> Hi Masami,
> 
> On 04/09/2018 12:58 PM, Masami Hiramatsu wrote:
> > Hi Ravi,
> >
> > On Wed,  4 Apr 2018 14:01:10 +0530
> > Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com> wrote:
> >
> >> @@ -2054,15 +2060,21 @@ char *synthesize_probe_trace_command(struct 
> >> probe_trace_event *tev)
> >>    }
> >>  
> >>    /* Use the tp->address for uprobes */
> >> -  if (tev->uprobes)
> >> +  if (tev->uprobes) {
> >>            err = strbuf_addf(&buf, "%s:0x%lx", tp->module, tp->address);
> >> -  else if (!strncmp(tp->symbol, "0x", 2))
> >> +          if (uprobe_ref_ctr_is_supported() &&
> >> +              tp->ref_ctr_offset &&
> >> +              err >= 0)
> >> +                  err = strbuf_addf(&buf, "(0x%lx)", tp->ref_ctr_offset);
> > If the kernel doesn't support uprobe_ref_ctr but the event requires
> > to increment uprobe_ref_ctr, I think we should (at least) warn user here.
> 
> pr_debug("A semaphore is associated with %s:%s and seems your kernel doesn't 
> support it.\n"
>          tev->group, tev->event);
> 
> Looks good?

I think it should be pr_warning() and return NULL, since user may not be able to
trace the event even if it is enabled.

> 
> >> @@ -776,14 +784,21 @@ static char *synthesize_sdt_probe_command(struct 
> >> sdt_note *note,
> >>  {
> >>    struct strbuf buf;
> >>    char *ret = NULL, **args;
> >> -  int i, args_count;
> >> +  int i, args_count, err;
> >> +  unsigned long long ref_ctr_offset;
> >>  
> >>    if (strbuf_init(&buf, 32) < 0)
> >>            return NULL;
> >>  
> >> -  if (strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
> >> -                          sdtgrp, note->name, pathname,
> >> -                          sdt_note__get_addr(note)) < 0)
> >> +  err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
> >> +                  sdtgrp, note->name, pathname,
> >> +                  sdt_note__get_addr(note));
> >> +
> >> +  ref_ctr_offset = sdt_note__get_ref_ctr_offset(note);
> >> +  if (uprobe_ref_ctr_is_supported() && ref_ctr_offset && err >= 0)
> >> +          err = strbuf_addf(&buf, "(0x%llx)", ref_ctr_offset);
> > We don't have to care about uprobe_ref_ctr support here, because
> > this information will be just cached, not directly written to
> > uprobe_events.
> 
> Sure, will remove the check.

Thanks!

> 
> Thanks for the review :).
> Ravi
> 


-- 
Masami Hiramatsu <mhira...@kernel.org>
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