tree 84a905ef62065f871f40a707c4d35c3cc2b4098d
parent a5df688aedcb4dd1a0c08af9a49858917daa9b2e
author Paul E. McKenney <paulmck@kernel.org> 1578340798 -0800
committer Paul E. McKenney <paulmck@kernel.org> 1578340798 -0800

rcu-tasks: *_ONCE() for rcu_tasks_cbs_head

The RCU tasks list of callbacks, rcu_tasks_cbs_head, is sampled locklessly
by rcu_tasks_kthread() when waiting for work to do.  This commit therefore
applies READ_ONCE() to that lockless sampling and WRITE_ONCE() to the
single potential store outside of rcu_tasks_kthread.

This data race was reported by KCSAN.  Not appropriate for backporting
due to failure being unlikely.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>