Commit-ID: 3b6505fd8eb86e3ef5ce12b34fe81e9edeb84475
Gitweb: https://git.kernel.org/tip/3b6505fd8eb86e3ef5ce12b34fe81e9edeb84475
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
AuthorDate: Wed, 12 Dec 2018 07:20:07 -0800
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
CommitDate: Fri, 25 Jan 2019 15:29:58 -0800
rcu: Protect rcu_check_gp_kthread_starvation() access to ->gp_flags
The rcu_check_gp_kthread_starvation() function can be invoked without
holding locks, so the access to the rcu_state structure's ->gp_flags
field must be protected with READ_ONCE(). This commit therefore adds
this protection.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8543a90d53f2..238150684fed 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1192,7 +1192,7 @@ static void rcu_check_gp_kthread_starvation(void)
pr_err("%s kthread starved for %ld jiffies! g%ld f%#x %s(%d) ->state=%#lx ->cpu=%d\n",
rcu_state.name, j,
(long)rcu_seq_current(&rcu_state.gp_seq),
- rcu_state.gp_flags,
+ READ_ONCE(rcu_state.gp_flags),
gp_state_getname(rcu_state.gp_state), rcu_state.gp_state,
gpk ? gpk->state : ~0, gpk ? task_cpu(gpk) : -1);
if (gpk) {
|