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rcu: Add failure tracing to rcutorture

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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>
This commit is contained in:
Paul E. McKenney
2011-10-02 07:44:32 -07:00
committed by Paul E. McKenney
parent a8eecf2248
commit 91afaf3002
4 changed files with 62 additions and 0 deletions
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18
kernel/rcutorture.c
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@ -913,6 +913,18 @@ rcu_torture_fakewriter(void *arg)
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 @@ static void rcu_torture_timer(unsigned long unused)
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 @@ static void rcu_torture_timer(unsigned long unused)
/* 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_torture_reader(void *arg)
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 @@ rcu_torture_reader(void *arg)
/* 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) {