Re: [PATCH] perf probe: Fix bug in perf probe with global variables

From: Arnaldo Carvalho de Melo
Date: Mon Apr 27 2015 - 12:39:06 EST


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@xxxxxxxxxxx>
>
> Thank you!!

Thanks, applied to perf/urgent.

- Arnaldo
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