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authorPaul E. McKenney <paulmck@kernel.org>2021-05-25 01:36:37 +0300
committerPaul E. McKenney <paulmck@kernel.org>2021-07-20 23:43:44 +0300
commitf8ab3fad80dddf3f2cecb53983063c4431058ca1 (patch)
treeef376a42d0d23f333a4813494900b85c0504afdd /kernel/rcu
parentbdb0cca0d11060fce8a8a44588ac1470c25d62bc (diff)
downloadlinux-f8ab3fad80dddf3f2cecb53983063c4431058ca1.tar.xz
rcu-tasks: Mark ->trc_reader_special.b.need_qs data races
There are several ->trc_reader_special.b.need_qs data races that are too low-probability for KCSAN to notice, but which will happen sooner or later. This commit therefore marks these accesses. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tasks.h8
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index f6b5320c4484..1cece5e9be9a 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -850,7 +850,7 @@ static DEFINE_IRQ_WORK(rcu_tasks_trace_iw, rcu_read_unlock_iw);
/* If we are the last reader, wake up the grace-period kthread. */
void rcu_read_unlock_trace_special(struct task_struct *t, int nesting)
{
- int nq = t->trc_reader_special.b.need_qs;
+ int nq = READ_ONCE(t->trc_reader_special.b.need_qs);
if (IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB) &&
t->trc_reader_special.b.need_mb)
@@ -916,7 +916,7 @@ static void trc_read_check_handler(void *t_in)
// Get here if the task is in a read-side critical section. Set
// its state so that it will awaken the grace-period kthread upon
// exit from that critical section.
- WARN_ON_ONCE(t->trc_reader_special.b.need_qs);
+ WARN_ON_ONCE(READ_ONCE(t->trc_reader_special.b.need_qs));
WRITE_ONCE(t->trc_reader_special.b.need_qs, true);
reset_ipi:
@@ -968,7 +968,7 @@ static bool trc_inspect_reader(struct task_struct *t, void *arg)
// state so that it will awaken the grace-period kthread upon exit
// from that critical section.
atomic_inc(&trc_n_readers_need_end); // One more to wait on.
- WARN_ON_ONCE(t->trc_reader_special.b.need_qs);
+ WARN_ON_ONCE(READ_ONCE(t->trc_reader_special.b.need_qs));
WRITE_ONCE(t->trc_reader_special.b.need_qs, true);
return true;
}
@@ -1103,7 +1103,7 @@ static void show_stalled_task_trace(struct task_struct *t, bool *firstreport)
".i"[is_idle_task(t)],
".N"[cpu > 0 && tick_nohz_full_cpu(cpu)],
READ_ONCE(t->trc_reader_nesting),
- " N"[!!t->trc_reader_special.b.need_qs],
+ " N"[!!READ_ONCE(t->trc_reader_special.b.need_qs)],
cpu);
sched_show_task(t);
}