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authorHe Kuang <hekuang@huawei.com>2015-05-28 13:28:54 +0000
committerArnaldo Carvalho de Melo <acme@redhat.com>2015-06-08 10:30:31 -0300
commite3d09ec8126fe2c9a3ade661e2126e215ca27a80 (patch)
tree1c5f517668eb72b3bfbf85a7c1935459792b2056 /tools/lib
parentf87027b9689d591ec22720944563a2d43ec835c4 (diff)
downloadlinux-e3d09ec8126fe2c9a3ade661e2126e215ca27a80.tar.gz
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>
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/traceevent/Makefile14
1 files changed, 13 insertions, 1 deletions
diff --git a/tools/lib/traceevent/Makefile b/tools/lib/traceevent/Makefile
index 84640394ebf9..6daaff652aff 100644
--- a/tools/lib/traceevent/Makefile
+++ b/tools/lib/traceevent/Makefile
@@ -23,6 +23,7 @@ endef
 # Allow setting CC and AR, or setting CROSS_COMPILE as a prefix.
 $(call allow-override,CC,$(CROSS_COMPILE)gcc)
 $(call allow-override,AR,$(CROSS_COMPILE)ar)
+$(call allow-override,NM,$(CROSS_COMPILE)nm)
 
 EXT = -std=gnu99
 INSTALL = install
@@ -157,8 +158,9 @@ PLUGINS_IN := $(PLUGINS:.so=-in.o)
 
 TE_IN    := $(OUTPUT)libtraceevent-in.o
 LIB_FILE := $(addprefix $(OUTPUT),$(LIB_FILE))
+DYNAMIC_LIST_FILE := $(OUTPUT)libtraceevent-dynamic-list
 
-CMD_TARGETS = $(LIB_FILE) $(PLUGINS)
+CMD_TARGETS = $(LIB_FILE) $(PLUGINS) $(DYNAMIC_LIST_FILE)
 
 TARGETS = $(CMD_TARGETS)
 
@@ -175,6 +177,9 @@ $(OUTPUT)libtraceevent.so: $(TE_IN)
 $(OUTPUT)libtraceevent.a: $(TE_IN)
 	$(QUIET_LINK)$(RM) $@; $(AR) rcs $@ $^
 
+$(OUTPUT)libtraceevent-dynamic-list: $(PLUGINS)
+	$(QUIET_GEN)$(call do_generate_dynamic_list_file, $(PLUGINS), $@)
+
 plugins: $(PLUGINS)
 
 __plugin_obj = $(notdir $@)
@@ -244,6 +249,13 @@ define do_install_plugins
 	done
 endef
 
+define do_generate_dynamic_list_file
+	(echo '{';							\
+	$(NM) -u -D $1 | awk 'NF>1 {print "\t"$$2";"}' | sort -u;	\
+	echo '};';							\
+	) > $2
+endef
+
 install_lib: all_cmd install_plugins
 	$(call QUIET_INSTALL, $(LIB_FILE)) \
 		$(call do_install,$(LIB_FILE),$(libdir_SQ))