--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa.c
@@ -904,7 +904,8 @@
 	ASSERT(spa->spa_state != POOL_STATE_UNINITIALIZED);
 
 	/*
-	 * Stop TRIM thread.
+	 * Stop TRIM thread in case spa_unload() wasn't called directly
+	 * before spa_deactivate().
 	 */
 	trim_thread_destroy(spa);
 
@@ -1024,6 +1025,11 @@
 	ASSERT(MUTEX_HELD(&spa_namespace_lock));
 
 	/*
+	 * Stop TRIM thread.
+	 */
+	trim_thread_destroy(spa);
+
+	/*
 	 * Stop async tasks.
 	 */
 	spa_async_suspend(spa);
--- sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
+++ sys/cddl/contrib/opensolaris/uts/common/fs/zfs/trim_map.c
@@ -501,6 +501,7 @@
 	/* The thread will set it back to != NULL on exit. */
 	while (spa->spa_trim_thread == NULL)
 		cv_wait(&spa->spa_trim_cv, &spa->spa_trim_lock);
+	spa->spa_trim_thread = NULL;
 	mutex_exit(&spa->spa_trim_lock);
 
 	cv_destroy(&spa->spa_trim_cv);
@@ -513,6 +514,8 @@
 
 	if (zfs_notrim)
 		return;
+	if (spa->spa_trim_thread == NULL)
+		return;
 
 	mutex_enter(&spa->spa_trim_lock);
 	cv_signal(&spa->spa_trim_cv);