diff options
Diffstat (limited to 'kernel/rcupdate.c')
| -rw-r--r-- | kernel/rcupdate.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index 0ccd009..760dfc2 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -115,7 +115,17 @@ void rcu_barrier(void) mutex_lock(&rcu_barrier_mutex); init_completion(&rcu_barrier_completion); atomic_set(&rcu_barrier_cpu_count, 0); + /* + * The queueing of callbacks in all CPUs must be atomic with + * respect to RCU, otherwise one CPU may queue a callback, + * wait for a grace period, decrement barrier count and call + * complete(), while other CPUs have not yet queued anything. + * So, we need to make sure that grace periods cannot complete + * until all the callbacks are queued. + */ + rcu_read_lock(); on_each_cpu(rcu_barrier_func, NULL, 0, 1); + rcu_read_unlock(); wait_for_completion(&rcu_barrier_completion); mutex_unlock(&rcu_barrier_mutex); } |