tree 824a091c37f36930f5789c1545883643311a33c6
parent 562125d6568fbe1d6a67bb989d5e8b6a6771b40c
author He Kuang <hekuang@huawei.com> 1432819734 +0000
committer Arnaldo Carvalho de Melo <acme@redhat.com> 1433770231 -0300

tools lib traceevent: Export dynamic symbols used by traceevent plugins

Traceevent plugins need dynamic symbols exported from libtraceevent.a,
otherwise a dlopen error will occur during plugins loading.

This patch uses dynamic-list-file to export dynamic symbols which will
be used in plugins to perf executable.

The problem is covered up if feature-libpython is enabled, because
PYTHON_EMBED_LDOPTS contains '-Xlinker --export-dynamic' which adds all
symbols to the dynamic symbol table. So we should reproduce the problem
by setting NO_LIBPYTHON=1.

Before this patch:

  (Prepare plugins)
  $ ls /root/.traceevent/plugins/
  plugin_sched_switch.so
  plugin_function.so
  ...

  $ perf record -e 'ftrace:function' ls

  $ perf script
    Warning: could not load plugin '/mnt/data/root/.traceevent/plugins/plugin_sched_switch.so'
    /root/.traceevent/plugins/plugin_sched_switch.so: undefined symbol: pevent_unregister_event_handler

    Warning: could not load plugin '/root/.traceevent/plugins/plugin_function.so'
    /root/.traceevent/plugins/plugin_function.so: undefined symbol: warning
    ...
           :1049  1049 [000]  9666.754487: ftrace:function:  ffffffff8118bc50 <-- ffffffff8118c5b3
           :1049  1049 [000]  9666.754487: ftrace:function:  ffffffff818e2440 <-- ffffffff8118bc75
           :1049  1049 [000]  9666.754487: ftrace:function:  ffffffff8106eee0 <-- ffffffff811212e2

After this patch:

  $ perf record -e 'ftrace:function' ls
  $ perf script
           :1049  1049 [000]  9666.754487: ftrace:function: __set_task_comm
           :1049  1049 [000]  9666.754487: ftrace:function:    _raw_spin_lock
           :1049  1049 [000]  9666.754487: ftrace:function: task_tgid_nr_ns
           ...

Signed-off-by: He Kuang <hekuang@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1432819735-35040-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>