epoch(9): Don't trigger taskq enqueue before the grouptaskqs are setup

If EARLY_AP_STARTUP is not defined it is possible for an epoch to be
allocated prior to it being possible to call epoch_call without
issue.

Based on patch by andrew@

PR:		229014
Reported by:	andrew

1 files changed, 14 insertions, 1 deletions

diff --git a/sys/kern/subr_epoch.c b/sys/kern/subr_epoch.c
index b5e6f285062f..9a6f6a68eed9 100644
--- a/sys/kern/subr_epoch.c
+++ b/sys/kern/subr_epoch.c
@@ -176,9 +176,18 @@ done:
 	global_epoch = epoch_alloc(0);
 	global_epoch_preempt = epoch_alloc(EPOCH_PREEMPT);
 }
-
 SYSINIT(epoch, SI_SUB_TASKQ + 1, SI_ORDER_FIRST, epoch_init, NULL);
 
+#if !defined(EARLY_AP_STARTUP)
+static void
+epoch_init_smp(void *dummy __unused)
+{
+	inited = 2;
+}
+SYSINIT(epoch_smp, SI_SUB_SMP + 1, SI_ORDER_FIRST, epoch_init_smp, NULL);
+#endif
+
+
 static void
 epoch_init_numa(epoch_t epoch)
 {
@@ -570,6 +579,10 @@ epoch_call(epoch_t epoch, epoch_context_t ctx, void (*callback) (epoch_context_t
 	/* too early in boot to have epoch set up */
 	if (__predict_false(epoch == NULL))
 		goto boottime;
+#if !defined(EARLY_AP_STARTUP)
+	if (__predict_false(inited < 2))
+		goto boottime;
+#endif
 
 	critical_enter();
 	*DPCPU_PTR(epoch_cb_count) += 1;