Make sure to handle the pending bypass queue before we switch to the final de-offload state. We'll have to be careful and later set SEGCBLIST_SOFTIRQ_ONLY before re-enabling again IRQs, or new bypass callbacks could be queued in the meantine.
Inspired-by: Paul E. McKenney <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Josh Triplett <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: Joel Fernandes <[email protected]> --- kernel/rcu/tree_plugin.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 3361bd351f3b..cee15841c178 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2302,11 +2302,17 @@ static void __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) !rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB | SEGCBLIST_KTHREAD_GP)); + rcu_nocb_lock_irqsave(rdp, flags); /* Make sure nocb timer won't stay around */ - rcu_nocb_lock_irqsave(rdp, flags); WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_OFF); - rcu_nocb_unlock_irqrestore(rdp, flags); del_timer_sync(&rdp->nocb_timer); + /* + * Flush bypass. While IRQs are disabled and once we set + * SEGCBLIST_SOFTIRQ_ONLY, no callback is supposed to be + * enqueued on bypass. + */ + rcu_nocb_flush_bypass(rdp, NULL, jiffies); + rcu_nocb_unlock_irqrestore(rdp, flags); } static long rcu_nocb_rdp_deoffload(void *arg) -- 2.28.0
