Re: [PATCH RESEND 1/2] tools lib traceevent: Export dynamic symbols used by traceevent plugins

[He Kuang]

hi, Arnaldo

ping..

On 2015/5/28 21:28, He Kuang wrote:
> 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@xxxxxxxxxx>
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>   tools/lib/traceevent/Makefile | 14 +++++++++++++-
>   tools/perf/Makefile.perf      | 14 ++++++++++++--
>   2 files changed, 25 insertions(+), 3 deletions(-)
>
> diff --git a/tools/lib/traceevent/Makefile b/tools/lib/traceevent/Makefile
> index 8464039..6daaff6 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))
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 5816a3b..b1dfcd8 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -173,6 +173,9 @@ endif
>   LIBTRACEEVENT = $(TE_PATH)libtraceevent.a
>   export LIBTRACEEVENT
>
> +LIBTRACEEVENT_DYNAMIC_LIST = $(TE_PATH)libtraceevent-dynamic-list
> +LDFLAGS += -Xlinker --dynamic-list=$(LIBTRACEEVENT_DYNAMIC_LIST)
> +
>   LIBAPI = $(LIB_PATH)libapi.a
>   export LIBAPI
>
> @@ -278,7 +281,7 @@ build := -f $(srctree)/tools/build/Makefile.build dir=. obj
>   $(PERF_IN): $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h FORCE
>   	$(Q)$(MAKE) $(build)=perf
>
> -$(OUTPUT)perf: $(PERFLIBS) $(PERF_IN)
> +$(OUTPUT)perf: $(PERFLIBS) $(PERF_IN) $(LIBTRACEEVENT_DYNAMIC_LIST)
>   	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $(PERF_IN) $(LIBS) -o $@
>
>   $(GTK_IN): FORCE
> @@ -373,7 +376,13 @@ $(LIB_FILE): $(LIBPERF_IN)
>   LIBTRACEEVENT_FLAGS += plugin_dir=$(plugindir_SQ)
>
>   $(LIBTRACEEVENT): FORCE
> -	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent.a plugins
> +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent.a
> +
> +libtraceevent_plugins: FORCE
> +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) plugins
> +
> +$(LIBTRACEEVENT_DYNAMIC_LIST): libtraceevent_plugins
> +	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) $(OUTPUT)libtraceevent-dynamic-list
>
>   $(LIBTRACEEVENT)-clean:
>   	$(call QUIET_CLEAN, libtraceevent)
> @@ -555,4 +564,5 @@ FORCE:
>   .PHONY: all install clean config-clean strip install-gtk
>   .PHONY: shell_compatibility_test please_set_SHELL_PATH_to_a_more_modern_shell
>   .PHONY: $(GIT-HEAD-PHONY) TAGS tags cscope FORCE single_dep
> +.PHONY: libtraceevent_plugins

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