[PATCH 1/2] trace: module: Maintain a valid user count

[Steven Rostedt]

From: Romain Izard <romain.izard.pro@xxxxxxxxx>

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@xxxxxxxxx

Acked-by: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # 2.6.35
Fixes: c1ab9cab7509 "merge conflict resolution"
Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
 include/trace/events/module.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 11fd51b..daa60c7 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -80,7 +80,7 @@ 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);
 	),
 
-- 
1.8.5.3


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/