On Tue, Jan 15, 2013 at 3:58 PM, Arnaldo Carvalho de Melo <a...@redhat.com> wrote: > > Em Mon, Jan 14, 2013 at 03:14:02PM +0100, Stephane Eranian escreveu: > > Hi, > > > > I was trying to use the --uid option of perf record but it fails for > > me no matter > > what I tried. Looks like the goal of this option is to measure ALL the > > processes > > owned by the specified uid. Each process is measured in per-thread mode. > > > > However for me it failed on all my attempts when running with 3.8.0-rc3 on > > Ubuntu Quantal. > > > > $ perf record --uid=eranian sleep 4 > > Error: > > Permission error - are you root? > > Consider tweaking /proc/sys/kernel/perf_event_paranoid: > > -1 - Not paranoid at all > > 0 - Disallow raw tracepoint access for unpriv > > 1 - Disallow cpu events for unpriv > > 2 - Disallow kernel profiling for unpriv > > sleep: Terminated > > > > You don't want to be root to run this command. Should not require > > But you have to due to the problem you noticed below. > > > to measure the processes I own. So the error message is confusing > > here. > > indeed > > > After some debugging, I came to the conclusion that this command > > fails when it hits the sshd daemon: > > > > eranian 2439 0.0 0.0 110424 1968 ? S 15:07 0:00 sshd: > > eranian@pts/2 > > root 2301 0.0 0.0 110424 4420 ? Ss 15:07 0:00 sshd: > > eranian [priv] > > > > I mean the sshd process owned by me. It is owned by me but I cannot attached > > an event to it. I get EACCES and I suspect it's because of missing > > ptrace privilege. > > The sshd binary is obviously not setuid. So there is something else > > preventing > > ptrace. In fact, even strace -p 2349 fails. Looked online and there > > were a couple > > of mentions to the Yama security model and the ptrace_scope sysctl > > control. I tried > > that and it did not help. > > > > So looks to me that something is broken somewhere. If the kernel > > restrictions are > > normal, then I think perf record should warn that it has to skip the > > sshd process and > > continue with the other processes owned by me. That seems more useful than > > the > > current situation. But I may be missing something here. If so please > > explain to me. > > Right, I need to resume working on properly fixing this, I got > sidetracked when I got the same point as you in the above analysis :-\ > > Will try to recover the conversations I had about this. > What I don't understand is how it could have ever worked? Or maybe I ran into this just because I use ssh to connect to my machine.
> > - Arnaldo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
