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From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: He Kuang <hekuang@huawei.com>,
	a.p.zijlstra@chello.nl, mingo@redhat.com, paulus@samba.org,
	wangnan0@huawei.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf probe: Fix bug in perf probe with global variables
Date: Mon, 27 Apr 2015 13:38:53 -0300	[thread overview]
Message-ID: <20150427163853.GD16849@kernel.org> (raw)
In-Reply-To: <553C37A6.3090206@hitachi.com>

Em Sun, Apr 26, 2015 at 09:56:06AM +0900, Masami Hiramatsu escreveu:
> (2015/04/25 17:08), He Kuang wrote:
> > There are missing curly braces which causes find_variable() return wrong
> > value when probing with global variables.
> > 
> > This problem can be reproduced as following:
> > 
> >   $ perf probe -v --add='generic_perform_write global_variable_for_test'
> >   ...
> >   Try to find probe point from debuginfo.
> >   Probe point found: generic_perform_write+0
> >   Searching 'global_variable_for_test' variable in context.
> >   An error occurred in debuginfo analysis (-2).
> >     Error: Failed to add events. Reason: No such file or directory (Code: -2)
> > 
> > After this patch:
> > 
> >   $ perf probe -v --add='generic_perform_write global_variable_for_test'
> >   ...
> >   Converting variable global_variable_for_test into trace event.
> >   global_variable_for_test type is int.
> >   Found 1 probe_trace_events.
> >   Opening /sys/kernel/debug/tracing/kprobe_events write=1
> >   Added new event:
> >   Writing event: p:probe/generic_perform_write _stext+1237464
> >   global_variable_for_test=@global_variable_for_test+0:s32
> >     probe:generic_perform_write (on generic_perform_write with
> >     global_variable_for_test)
> > 
> >   You can now use it in all perf tools, such as:
> > 
> >       perf record -e probe:generic_perform_write -aR sleep 1
> 
> Oops, that's my fault! :(
> 
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> 
> Thank you!!

Thanks, applied to perf/urgent.

- Arnaldo

  reply	other threads:[~2015-04-27 16:38 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-25  8:08 [PATCH] perf probe: Fix bug in perf probe with global variables He Kuang
2015-04-26  0:56 ` Masami Hiramatsu
2015-04-27 16:38   ` Arnaldo Carvalho de Melo [this message]
2015-05-01 10:15 ` [tip:perf/urgent] perf probe: Fix bug with global variables handling tip-bot for He Kuang

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