rcu: Add failure tracing to rcutorture
Trace the rcutorture RCU accesses and dump the trace buffer when the
first failure is detected.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 764825c2..df35228 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -913,6 +913,18 @@
return 0;
}
+void rcutorture_trace_dump(void)
+{
+ static atomic_t beenhere = ATOMIC_INIT(0);
+
+ if (atomic_read(&beenhere))
+ return;
+ if (atomic_xchg(&beenhere, 1) != 0)
+ return;
+ do_trace_rcu_torture_read(cur_ops->name, (struct rcu_head *)~0UL);
+ ftrace_dump(DUMP_ALL);
+}
+
/*
* RCU torture reader from timer handler. Dereferences rcu_torture_current,
* incrementing the corresponding element of the pipeline array. The
@@ -934,6 +946,7 @@
rcu_read_lock_bh_held() ||
rcu_read_lock_sched_held() ||
srcu_read_lock_held(&srcu_ctl));
+ do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
if (p == NULL) {
/* Leave because rcu_torture_writer is not yet underway */
cur_ops->readunlock(idx);
@@ -951,6 +964,8 @@
/* Should not happen, but... */
pipe_count = RCU_TORTURE_PIPE_LEN;
}
+ if (pipe_count > 1)
+ rcutorture_trace_dump();
__this_cpu_inc(rcu_torture_count[pipe_count]);
completed = cur_ops->completed() - completed;
if (completed > RCU_TORTURE_PIPE_LEN) {
@@ -994,6 +1009,7 @@
rcu_read_lock_bh_held() ||
rcu_read_lock_sched_held() ||
srcu_read_lock_held(&srcu_ctl));
+ do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
if (p == NULL) {
/* Wait for rcu_torture_writer to get underway */
cur_ops->readunlock(idx);
@@ -1009,6 +1025,8 @@
/* Should not happen, but... */
pipe_count = RCU_TORTURE_PIPE_LEN;
}
+ if (pipe_count > 1)
+ rcutorture_trace_dump();
__this_cpu_inc(rcu_torture_count[pipe_count]);
completed = cur_ops->completed() - completed;
if (completed > RCU_TORTURE_PIPE_LEN) {