tracing: Remove side effect from module tracepoints that caused a GPF
Remove the @refcnt argument, because it has side-effects, and arguments with
side-effects are not skipped by the jump over disabled instrumentation and are
executed even when the tracepoint is disabled.
This was also causing a GPF as found by Randy Dunlap:
Subject: 2.6.33 GP fault only when built with tracing
LKML-Reference: <4BA2B69D.3000309@oracle.com>
Note, the current 2.6.34-rc has a fix for the actual cause of the GPF,
but this fixes one of its triggers.
Tested-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4BA97FA7.6040406@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/include/linux/module.h b/include/linux/module.h
index 5e869ff..393ec39 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -460,8 +460,7 @@
if (module) {
preempt_disable();
__this_cpu_inc(module->refptr->count);
- trace_module_get(module, _THIS_IP_,
- __this_cpu_read(module->refptr->count));
+ trace_module_get(module, _THIS_IP_);
preempt_enable();
}
}
@@ -475,8 +474,7 @@
if (likely(module_is_live(module))) {
__this_cpu_inc(module->refptr->count);
- trace_module_get(module, _THIS_IP_,
- __this_cpu_read(module->refptr->count));
+ trace_module_get(module, _THIS_IP_);
}
else
ret = 0;
diff --git a/include/trace/events/module.h b/include/trace/events/module.h
index 4b0f48b..a585f81 100644
--- a/include/trace/events/module.h
+++ b/include/trace/events/module.h
@@ -53,9 +53,9 @@
DECLARE_EVENT_CLASS(module_refcnt,
- TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
+ TP_PROTO(struct module *mod, unsigned long ip),
- TP_ARGS(mod, ip, refcnt),
+ TP_ARGS(mod, ip),
TP_STRUCT__entry(
__field( unsigned long, ip )
@@ -65,7 +65,7 @@
TP_fast_assign(
__entry->ip = ip;
- __entry->refcnt = refcnt;
+ __entry->refcnt = __this_cpu_read(mod->refptr->count);
__assign_str(name, mod->name);
),
@@ -75,16 +75,16 @@
DEFINE_EVENT(module_refcnt, module_get,
- TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
+ TP_PROTO(struct module *mod, unsigned long ip),
- TP_ARGS(mod, ip, refcnt)
+ TP_ARGS(mod, ip)
);
DEFINE_EVENT(module_refcnt, module_put,
- TP_PROTO(struct module *mod, unsigned long ip, int refcnt),
+ TP_PROTO(struct module *mod, unsigned long ip),
- TP_ARGS(mod, ip, refcnt)
+ TP_ARGS(mod, ip)
);
TRACE_EVENT(module_request,
