Add lock order checking for smr_barrier(9). This is similar to the

checking done in taskq_barrier(9) and timeout_barrier(9).

OK mpi@

1 files changed, 22 insertions, 1 deletions

diff --git a/sys/kern/kern_smr.c b/sys/kern/kern_smr.c
index 0913aee8683..eadf828cfd6 100644
--- a/sys/kern/kern_smr.c
+++ b/sys/kern/kern_smr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_smr.c,v 1.1 2019/02/26 14:24:21 visa Exp $	*/
+/*	$OpenBSD: kern_smr.c,v 1.2 2019/05/14 03:27:43 visa Exp $	*/
 
 /*
  * Copyright (c) 2019 Visa Hankala
@@ -25,6 +25,7 @@
 #include <sys/proc.h>
 #include <sys/smr.h>
 #include <sys/time.h>
+#include <sys/witness.h>
 
 #include <machine/cpu.h>
 
@@ -45,6 +46,18 @@ struct timeout		smr_wakeup_tmo;
 unsigned int		smr_expedite;
 unsigned int		smr_ndeferred;
 
+#ifdef WITNESS
+static const char smr_lock_name[] = "smr";
+struct lock_object smr_lock_obj = {
+	.lo_name = smr_lock_name,
+	.lo_flags = LO_WITNESS | LO_INITIALIZED | LO_SLEEPABLE |
+	    (LO_CLASS_RWLOCK << LO_CLASSSHIFT)
+};
+struct lock_type smr_lock_type = {
+	.lt_name = smr_lock_name
+};
+#endif
+
 static inline int
 smr_cpu_is_idle(struct cpu_info *ci)
 {
@@ -55,6 +68,7 @@ void
 smr_startup(void)
 {
 	SIMPLEQ_INIT(&smr_deferred);
+	WITNESS_INIT(&smr_lock_obj, &smr_lock_type);
 	kthread_create_deferred(smr_create_thread, NULL);
 }
 
@@ -102,11 +116,16 @@ smr_thread(void *arg)
 
 		smr_grace_wait();
 
+		WITNESS_CHECKORDER(&smr_lock_obj, LOP_NEWORDER, NULL);
+		WITNESS_LOCK(&smr_lock_obj, 0);
+
 		while ((smr = SIMPLEQ_FIRST(&deferred)) != NULL) {
 			SIMPLEQ_REMOVE_HEAD(&deferred, smr_list);
 			smr->smr_func(smr->smr_arg);
 		}
 
+		WITNESS_UNLOCK(&smr_lock_obj, 0);
+
 		getmicrouptime(&end);
 		timersub(&end, &start, &elapsed);
 		if (elapsed.tv_sec >= 5 &&
@@ -289,6 +308,8 @@ smr_barrier_impl(int expedite)
 	assertwaitok();
 	SMR_ASSERT_NONCRITICAL();
 
+	WITNESS_CHECKORDER(&smr_lock_obj, LOP_NEWORDER, NULL);
+
 	smr_init(&smr);
 	smr_call_impl(&smr, smr_barrier_func, &c, expedite);
 	cond_wait(&c, "smrbar");