[PATCH] trace: module: Maintain a valid user count

From: Romain Izard
Date: Mon Mar 03 2014 - 13:18:20 EST

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.

Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
include/trace/events/module.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 161932737416..1228d963b6d1 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -78,7 +78,8 @@ DECLARE_EVENT_CLASS(module_refcnt,

__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);


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