rcu: Add WRITE_ONCE() to rcu_state ->gp_start
authorPaul E. McKenney <paulmck@kernel.org>
Mon, 20 Jan 2020 23:29:04 +0000 (15:29 -0800)
committerPaul E. McKenney <paulmck@kernel.org>
Thu, 20 Feb 2020 23:58:23 +0000 (15:58 -0800)
commit59881bcd85a06565c53fd13ce3b0ad7fa55e560c
tree675ba755b0405c7967b28e4235c56eca27a7f699
parent57721fd15a02f7df9dad1f3cca27f21e03ee118f
rcu: Add WRITE_ONCE() to rcu_state ->gp_start

The rcu_state structure's ->gp_start field is read locklessly, so this
commit adds the WRITE_ONCE() to an update in order to provide proper
documentation and READ_ONCE()/WRITE_ONCE() pairing.

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>
kernel/rcu/tree_stall.h