On Sat, 7 Jun 2014, Thomas Gleixner wrote:
> On Sat, 7 Jun 2014, Sasha Levin wrote:
> So one thing which might give us at least some data is the debug patch
> below. With CONFIG_STACKTRACE enabled and
>
> # echo 1 >/sys/kernel/debug/tracing/options/stacktrace
>
> we should get a recording of rcu_free() calls along with the
> stacktrace for each. So we should be able to see which code path
> actually queued the thing. Maybe that's enough of an hint, but at
> least it gives us an idea which code path to instrument further.
This one is better..
Thanks,
tglx
---------------------
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 962d1d5..7241235 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -698,6 +698,7 @@ EXPORT_SYMBOL_GPL(call_rcu);
void kfree_call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *rcu))
{
+ trace_printk("head: %p func: %pS\n", head, func);
__call_rcu(head, func, &rcu_preempt_state, -1, 1);
}
EXPORT_SYMBOL_GPL(kfree_call_rcu);
@@ -1091,6 +1092,7 @@ static void rcu_preempt_check_callbacks(int cpu)
void kfree_call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *rcu))
{
+ trace_printk("head: %p func: %pS\n", head, func);
__call_rcu(head, func, &rcu_sched_state, -1, 1);
}
EXPORT_SYMBOL_GPL(kfree_call_rcu);
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index e0731c3..fd5cafd 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -693,6 +693,9 @@ repeat:
switch (obj->state) {
case ODEBUG_STATE_ACTIVE:
+ trace_printk("free %p obj %p\n", address,
+ obj->object);
+ tracing_off();
debug_print_object(obj, "free");
descr = obj->descr;
state = obj->state;
--
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