linux-kernel - Re: perf probe -d failing to delete probes

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Date:   Tue, 3 Dec 2019 07:18:54 +0900
From:   Masami Hiramatsu <mhiramat@...nel.org>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: perf probe -d failing to delete probes

Hi Arnaldo,

On Mon, 2 Dec 2019 16:04:52 -0300
Arnaldo Carvalho de Melo <acme@...nel.org> wrote:

> Em Mon, Dec 02, 2019 at 03:59:58PM -0300, Arnaldo Carvalho de Melo escreveu:
> > Em Fri, Nov 29, 2019 at 12:13:24PM -0300, Arnaldo Carvalho de Melo escreveu:
> > > 
> > > Hi Masami,
> > > 
> > >    Can you please take a look at this?
> > > 
> > > [root@...co perf]# perf probe -l
> > >   probe_perf:map__map_ip (on ui__warn_map_erange+222@...f/tools/perf/builtin-top.c in /home/acme/bin/perf)
> > >   probe_perf:map__map_ip (on ui__warn_map_erange+222@...f/tools/perf/builtin-top.c in /home/acme/bin/perf)
> > >   probe_perf:map__map_ip (on perf_evlist__set_paused+222@...l/evlist.c in /home/acme/bin/perf)
> > >   probe_perf:map__map_ip (on perf_evlist__resume+222@...l/evlist.c in /home/acme/bin/perf)
> > >   probe_perf:map__map_ip (on perf_evsel__group_desc+222@...l/evsel.c in /home/acme/bin/perf)
> > >   probe_perf:map__map_ip (on svg_partial_wakeline+222@...l/svghelper.c in /home/acme/bin/perf)
> > > [root@...co perf]# perf probe -d probe_perf:map_*
> > > "probe_perf:map_*" does not hit any event.
> > >   Error: Failed to delete events.
> > > [root@...co perf]# perf probe -d probe_perf:*
> > > "probe_perf:*" does not hit any event.
> > >   Error: Failed to delete events.
> > > [root@...co perf]# perf probe -d probe*:*
> > > "probe*:*" does not hit any event.
> > >   Error: Failed to delete events.
> > > [root@...co perf]# perf probe -d '*:*'
> > > "*:*" does not hit any event.
> > >   Error: Failed to delete events.
> > > [root@...co perf]#
> > 
> > [root@...co ~]# perf probe -l
> >   probe_perf:map__map_ip (on process_sample_event+6663@...ls/perf/builtin-script.c in /home/acme/bin/perf)
> >   probe_perf:map__map_ip (on process_sample_event+6739@...ls/perf/builtin-script.c in /home/acme/bin/perf)
> >   probe_perf:map__map_ip (on unwind_entry+436@...l/machine.c in /home/acme/bin/perf)
> >   probe_perf:map__map_ip (on machine__process_extra_kernel_map+31@...l/machine.c in /home/acme/bin/perf)
> >   probe_perf:map__map_ip (on __maps__insert+192@...l/map.c in /home/acme/bin/perf)
> >   probe_perf:map__map_ip (on dso__process_kernel_symbol+336@...l/symbol-elf.c in /home/acme/bin/perf)
> > [root@...co ~]# ls -la /sys/kernel/debug/tracing/events/probe_perf/
> > total 0
> > drwxr-xr-x.   3 root root 0 Nov 29 12:09 .
> > drwxr-xr-x. 113 root root 0 Dec  2 15:56 ..
> > -rw-r--r--.   1 root root 0 Nov 29 12:09 enable
> > -rw-r--r--.   1 root root 0 Nov 29 12:09 filter
> > drwxr-xr-x.   2 root root 0 Nov 29 12:09 map__map_ip
> > [root@...co ~]#
> > 
> > Trying to figure out how to remove it via debugfs/tracefs
> 
> [root@...co ~]# cat /sys/kernel/debug/tracing/dynamic_events
> p:probe_perf/map__map_ip /home/acme/bin/perf:0x000000000005f257
> p:probe_perf/map__map_ip /home/acme/bin/perf:0x000000000005f2a3
> p:probe_perf/map__map_ip /home/acme/bin/perf:0x00000000000fda24
> p:probe_perf/map__map_ip /home/acme/bin/perf:0x00000000000fdacf
> p:probe_perf/map__map_ip /home/acme/bin/perf:0x00000000001028d0
> p:probe_perf/map__map_ip /home/acme/bin/perf:0x000000000016dd90
> [root@...co ~]#
> 
> [root@...co ~]# cat /sys/kernel/debug/tracing/kprobe_events
> [root@...co ~]#
> 
> [root@...co ~]# echo > /sys/kernel/debug/tracing/kprobe_events
> [root@...co ~]# perf probe -l
>   probe_perf:map__map_ip (on process_sample_event+6663@...ls/perf/builtin-script.c in /home/acme/bin/perf)
>   probe_perf:map__map_ip (on process_sample_event+6739@...ls/perf/builtin-script.c in /home/acme/bin/perf)
>   probe_perf:map__map_ip (on unwind_entry+436@...l/machine.c in /home/acme/bin/perf)
>   probe_perf:map__map_ip (on machine__process_extra_kernel_map+31@...l/machine.c in /home/acme/bin/perf)
>   probe_perf:map__map_ip (on __maps__insert+192@...l/map.c in /home/acme/bin/perf)
>   probe_perf:map__map_ip (on dso__process_kernel_symbol+336@...l/symbol-elf.c in /home/acme/bin/perf)
> [root@...co ~]#
> 
> Finally it works:
> 
> [root@...co ~]# echo > /sys/kernel/debug/tracing/dynamic_events
> [root@...co ~]# cat /sys/kernel/debug/tracing/dynamic_events
> [root@...co ~]#
> [root@...co ~]# perf probe -l
> [root@...co ~]#
> 
> A workaround, now to find out why 'perf probe -d '*:*' and the other
> reported variants are failing...
> 

Thank you for pointing it out. You can use '*' instead of '*:*' to list them all.
Anyway, there seems an inssue when I introduced multiprobe support.
I'll fix it soon.

Thanks,

> - Arnaldo


-- 
Masami Hiramatsu <mhiramat@...nel.org>