Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1754714AbcLNHhC (ORCPT <rfc822;w@1wt.eu>);
        Wed, 14 Dec 2016 02:37:02 -0500
Received: from mail-wj0-f194.google.com ([209.85.210.194]:33503 "EHLO
        mail-wj0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1751055AbcLNHhB (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Wed, 14 Dec 2016 02:37:01 -0500
Date: Wed, 14 Dec 2016 08:36:56 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Alexis Berlemont <alexis.berlemont@gmail.com>
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, mingo@redhat.com,
        acme@kernel.org, alexander.shishkin@linux.intel.com,
        Jiri Olsa <jolsa@redhat.com>
Subject: Re: [PATCH v5 0/2] perf probe: add sdt probes arguments into the
 uprobe cmd string
Message-ID: <20161214073656.GB1635@gmail.com>
References: <20161207122610.008da636793d38a39accf29b@kernel.org>
 <20161214000732.1710-1-alexis.berlemont@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20161214000732.1710-1-alexis.berlemont@gmail.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1883
Lines: 55


* Alexis Berlemont <alexis.berlemont@gmail.com> wrote:

> Hi Masami,
> 
> Many thanks for your mail.
> 
> Here is another patch set which tries to fix the points you mentioned:
> 
> * Skip the arguments containing a constant ($123); 
> * Review the code in charge of the register renaming (search for '%'
>   and parse it);
> * Minor changes (print the argument in case of error, skipping, check
>   the sdt arg type index);
> 
> Many thanks,
> 
> Alexis.
> 
> Alexis Berlemont (2):
>   perf sdt: add scanning of sdt probles arguments
>   perf probe: add sdt probes arguments into the uprobe cmd string

I'd like to hijack this thread to report an SDT oddity - one of my boxen reports 
lots of SDT tracepoints in 'perf list':

  mem:<addr>[/len][:access]                          [Hardware breakpoint]

  sdt_libc:lll_lock_wait_private                     [SDT event]
  sdt_libc:longjmp                                   [SDT event]
  sdt_libc:longjmp_target                            [SDT event]
  sdt_libc:memory_arena_new                          [SDT event]
  sdt_libc:memory_arena_retry                        [SDT event]
  sdt_libc:memory_arena_reuse                        [SDT event]
  sdt_libc:memory_arena_reuse_free_list              [SDT event]
  sdt_libc:memory_arena_reuse_wait                   [SDT event]
  sdt_libc:memory_calloc_retry                       [SDT event]
  sdt_libc:memory_heap_free                          [SDT event]
  ...

But none of them work:

  Error:  No permissions to read /sys/kernel/debug/tracing/events/sdt_libc/longjmp
  Hint:   Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing'

  ...

  Error:  File /sys/kernel/debug/tracing/events/sdt_libc/longjmp not found.
  Hint:   Perhaps this kernel misses some CONFIG_ setting to enable this feature?.

What kind of patches are required for SDT probes to work?

Thanks,

	Ingo