Messages in this thread | | | Date | Tue, 20 Sep 2016 08:05:57 +0900 | From | Masami Hiramatsu <> | Subject | Re: failed to add c++ probe |
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On Mon, 19 Sep 2016 11:54:02 +0200 Jiri Olsa <jolsa@redhat.com> wrote:
> hi, > Thomas reported failure to add an uprobe on libstdc++.so.6 like: > > [jolsa@krava perf]$ sudo ./perf probe -x /usr/lib64/libstdc++.so.6 'std::ostream::flush' > Semantic error :There is non-digit char in line number. > Error: Command Parse Error.
Ah, I should start adding mangling support on perf probe...
> it does not work also if I use the mangled name like: > > [jolsa@krava perf]$ sudo ./perf probe -x /usr/lib64/libstdc++.so.6 '_ZSt5flushIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_' > Probe point '_ZSt5flushIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_' not found. > Error: Failed to add events.
Hmm, could you try to find mangled symbol from the library as below?
./perf probe -x /usr/lib64/libstdc++.so.6 -F \*
And also try to do adding probe with -v option again?
In my case, I could find the mangled symbol, but failed to setup the probe...
$ sudo ./perf probe -x /usr/lib/x86_64-linux-gnu/libstdc++.so.6 -v _ZSt5flushIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_ probe-definition(0): _ZSt5flushIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_ symbol:_ZSt5flushIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_ file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments symbol:catch file:(null) line:0 offset:0 return:0 lazy:(null) symbol:throw file:(null) line:0 offset:0 return:0 lazy:(null) symbol:rethrow file:(null) line:0 offset:0 return:0 lazy:(null) Could not open debuginfo. Try to use symbols. Opening /sys/kernel/debug/tracing//uprobe_events write=1 Writing event: p:probe_libstdc++/_ZSt5flushIwSt11char_traitsIwEERSt13basic_ostreamIT_T0_ES6_ /usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.21:0x1114c0 Failed to write event: Invalid argument Error: Failed to add events. Reason: Invalid argument (Code: -22)
dmsg -k said;
[143725.339609] Failed to allocate trace_uprobe.(-22) [143725.339612] Failed to parse address or file.
It seems we need to fix trace_uprobe.c at least.
Thank you!
-- Masami Hiramatsu <mhiramat@kernel.org>
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