rcu: Trace only after NULL-pointer check

Fix a bonehead error introduced when adding event tracing to rcutorture.
Move the traces to follow the NULL-pointer checks.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 5cfa23be43bd..ed1c72bd9c09 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -1000,12 +1000,12 @@ 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);
                 return;
         }
+        do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
         if (p->rtort_mbtest == 0)
                 atomic_inc(&n_rcu_torture_mberror);
         spin_lock(&rand_lock);
@@ -1063,13 +1063,13 @@ 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);
                         schedule_timeout_interruptible(HZ);
                         continue;
                 }
+                do_trace_rcu_torture_read(cur_ops->name, &p->rtort_rcu);
                 if (p->rtort_mbtest == 0)
                         atomic_inc(&n_rcu_torture_mberror);
                 cur_ops->read_delay(&rand);