Messages in this thread | | | From | Alexandre Ghiti <> | Subject | Perf tool regression from 07d369857808 | Date | Thu, 27 Feb 2020 13:23:19 +0100 |
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Hi Masami,
The commit 07d369857808 ("perf probe: Fix wrong address verification) found its way in kernel 4.19.98 (and debian 10) and I observed some regressions when I try to add probes in shared libraries. The symptoms are:
$ perf probe -f --exec=/home/aghiti/lib/libdpuhw.so --add 'log_rank_path=log_rank_path rank path:string' Failed to find symbol at 0x3bf0 Error: Failed to add events.
Whereas when I revert this patch, on the same shared library:
$ perf probe -f --exec=/home/aghiti/lib/libdpuhw.so --add 'log_rank_path=log_rank_path rank path:string' Added new event: probe_libdpuhw:log_rank_path_4 (on log_rank_path in /home/aghiti/lib/libdpuhw.so.2020.1.0 with rank path:string)
You can now use it in all perf tools, such as:
perf record -e probe_libdpuhw:log_rank_path_4 -aR sleep 1
Actually, I noted that this patch reverts a previous patch that stated that dwfl_module_addrsym could fail on shared libraries 664fee3dc379 ("perf probe: Do not use dwfl_module_addrsym if dwarf_diename finds symbol name").
Let me know if I can be of any help,
Thanks,
Alexandre Ghiti
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