Re: [PATCH v3] tracing: expose current->comm to [ku]probe events

From: Omar Sandoval
Date: Fri Jun 17 2016 - 13:52:57 EST


On Fri, Jun 17, 2016 at 12:19:27PM -0400, Steven Rostedt wrote:
> On Thu, 9 Jun 2016 11:55:34 +0900
> Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>
> > On Wed, 8 Jun 2016 18:38:02 -0700
> > Omar Sandoval <osandov@xxxxxxxxxxx> wrote:
> >
> > > From: Omar Sandoval <osandov@xxxxxx>
> > >
> > > ftrace is very quick to give up on saving the task command line (see
> > > `trace_save_cmdline()`). The workaround for events which really care
> > > about the command line is to explicitly assign it as part of the entry.
> > > However, this doesn't work for kprobe events, as there's no
> > > straightforward way to get access to current->comm. Add a kprobe/uprobe
> > > event variable $comm which provides exactly that.
> > >
> > > Signed-off-by: Omar Sandoval <osandov@xxxxxx>
> >
> > Looks good to me:)
> >
> > Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> >
> > > ---
> > > Alexei pointed out to me that this same functionality can be acheived
> > > with BPF and the bpf_get_current_comm() helper, so strictly speaking,
> > > this patch isn't necessary. It's still convenient for ad-hoc stuff,
> > > though, so I figured I'd throw this up and see what everyone thought.
> >
> > Anyway, I'd like to pull this patch since this still be useful
> > in handy way to get comm on ftrace :)
> >
>
> I pulled it.
>
> Thanks!
>
> -- Steve

Thanks, Steve!

--
Omar