trace: module: Maintain a valid user count

commit 098507ae3ec2331476fb52e85d4040c1cc6d0ef4 upstream.

The replacement of the 'count' variable by two variables 'incs' and
'decs' to resolve some race conditions during module unloading was done
in parallel with some cleanup in the trace subsystem, and was integrated
as a merge.

Unfortunately, the formula for this replacement was wrong in the tracing
code, and the refcount in the traces was not usable as a result.

Use 'count = incs - decs' to compute the user count.

Link: http://lkml.kernel.org/p/1393924179-9147-1-git-send-email-romain.izard.pro@gmail.com
Acked-by: Ingo Molnar <mingo@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Fixes: c1ab9cab7509 "merge conflict resolution"
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 1619327374164909b6f8aaea6a730b0821ec6ee2..ca298c7157aeb9ee17858c336a8ea7e777c7aae7 100644 (file)
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -78,7 +78,7 @@ DECLARE_EVENT_CLASS(module_refcnt,
 
        TP_fast_assign(
                __entry->ip     = ip;
-               __entry->refcnt = __this_cpu_read(mod->refptr->incs) + __this_cpu_read(mod->refptr->decs);
+               __entry->refcnt = __this_cpu_read(mod->refptr->incs) - __this_cpu_read(mod->refptr->decs);
                __assign_str(name, mod->name);
        ),