Patch "perf build: Fix traceevent plugins build race" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

perf build: Fix traceevent plugins build race

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
perf-build-fix-traceevent-plugins-build-race.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Jiri Olsa <[email protected]>
Date: Thu, 26 Nov 2015 14:54:04 +0100
Subject: perf build: Fix traceevent plugins build race

From: Jiri Olsa <[email protected]>

commit 67befc652845c8ffbefc8d173a6e6ced14d472f1 upstream.

Ingo reported following build failure:

  $ make clean install
  ...
    CC       plugin_kmem.o
  fixdep: error opening depfile: ./.plugin_hrtimer.o.d: No such file or directory
  /home/mingo/tip/tools/build/Makefile.build:77: recipe for target
  'plugin_hrtimer.o' failed
  make[3]: *** [plugin_hrtimer.o] Error 2
  Makefile:189: recipe for target 'plugin_hrtimer-in.o' failed
  make[2]: *** [plugin_hrtimer-in.o] Error 2
  Makefile.perf:414: recipe for target 'libtraceevent_plugins' failed
  make[1]: *** [libtraceevent_plugins] Error 2
  make[1]: *** Waiting for unfinished jobs....

Currently we have the install-traceevent-plugins target being dependent on $(LIBTRACEEVENT), which will actualy not build any plugin. So the install-traceevent-plugins target itself will try to build plugins, but..

Plugins built is also triggered by perf build itself via libtraceevent_plugins target.

This might cause a race having one make thread removing temp files from another and result in above error. Fixing this by having proper plugins build dependency before installing plugins.

---
 tools/perf/Makefile.perf |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -420,7 +420,7 @@ $(LIBTRACEEVENT)-clean:
 	$(call QUIET_CLEAN, libtraceevent)
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) O=$(OUTPUT) clean >/dev/null
 
-install-traceevent-plugins: $(LIBTRACEEVENT)
+install-traceevent-plugins: libtraceevent_plugins
 	$(Q)$(MAKE) -C $(TRACE_EVENT_DIR) $(LIBTRACEEVENT_FLAGS) O=$(OUTPUT) install_plugins
 
 $(LIBAPI): fixdep FORCE

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/perf-build-fix-traceevent-plugins-build-race.patch