From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E. McKenney" <paulmck@linux.ibm.com>
Subject: [PATCH tip/core/rcu 09/12] rcu: Protect rcu_check_gp_kthread_starvation() access to ->gp_flags
Date: Wed, 9 Jan 2019 13:28:31 -0800 [thread overview]
Message-ID: <20190109212834.1257-9-paulmck@linux.ibm.com> (raw)
In-Reply-To: <20190109212816.GA32282@linux.ibm.com>
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@linux.ibm.com>
---
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) {
--
2.17.1
next prev parent reply other threads:[~2019-01-09 21:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-09 21:28 [PATCH tip/core/rcu 0/12] Forward-progress changes for v5.1 Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 01/12] rcu: Accommodate zero jiffies_till_first_fqs and kthread kicking Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 02/12] rcu: Move rcu_cpu_kthread_task to rcu_data structure Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 03/12] rcu: Move rcu_cpu_kthread_status " Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 04/12] rcu: Remove unused rcu_cpu_kthread_loops per-CPU variable Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 05/12] rcu: Move rcu_cpu_has_work to rcu_data structure Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 06/12] rcu: Remove unused rcu_cpu_kthread_cpu per-CPU variable Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 07/12] rcu: Update NOCB comments Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 08/12] rcu: Improve diagnostics for failed RCU grace-period start Paul E. McKenney
2019-01-09 21:28 ` Paul E. McKenney [this message]
2019-01-09 21:28 ` [PATCH tip/core/rcu 10/12] rcu: Add sysrq rcu_node-dump capability Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 11/12] rcu: Do RCU GP kthread self-wakeup from softirq and interrupt Paul E. McKenney
2019-01-09 21:28 ` [PATCH tip/core/rcu 12/12] rcu: Prevent needless ->gp_seq_needed update in __note_gp_changes() Paul E. McKenney
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