diff --git a/log_manager/log_manager.cc b/log_manager/log_manager.cc
index 0772ceddc..8a721837f 100644
--- a/log_manager/log_manager.cc
+++ b/log_manager/log_manager.cc
@@ -771,9 +771,6 @@ static char* blockbuf_get_writepos(
                          */
                         bb_list->mlist_versno += 1;
                         ss_dassert(bb_list->mlist_versno%2 == 0);
-
-                        /** Unlock list */
-                        simple_mutex_unlock(&bb_list->mlist_mutex);
                     } else {
                         /**
                          * List and buffers are full.
@@ -865,7 +862,6 @@ static char* blockbuf_get_writepos(
         
         /** Unlock buffer */
         simple_mutex_unlock(&bb->bb_mutex);
-        ss_dassert(bb_list->mlist_mutex.sm_lock_thr != pthread_self());
         return pos;
 }
             
diff --git a/log_manager/test/testlog.c b/log_manager/test/testlog.c
index 3c495e787..a308cd55f 100644
--- a/log_manager/test/testlog.c
+++ b/log_manager/test/testlog.c
@@ -40,9 +40,12 @@ static void* thr_run_morelog(void* data);
 #define NTHR 256
 #define NITER 100
 
+#if 1
+#  define TEST1
+#endif
+
 #if 0
-#define TEST1
-#define TEST2
+#  define TEST2
 #endif
 
 #define TEST3
@@ -172,13 +175,13 @@ int main(int argc, char* argv[])
 
         do {
             skygw_message_wait(mes);
-            simple_mutex_lock(mtx, TRUE);
+            simple_mutex_lock(mtx, true);
             if (nactive > 0) {
                 simple_mutex_unlock(mtx);
                 continue;
             }
             break;
-        } while(TRUE);
+        } while(true);
 
         for (i=0; i<NTHR; i++) {
             pthread_join(thr[i]->tid, NULL);
@@ -223,13 +226,13 @@ int main(int argc, char* argv[])
         
         do {
             skygw_message_wait(mes);
-            simple_mutex_lock(mtx, TRUE);
+            simple_mutex_lock(mtx, true);
             if (nactive > 0) {
                 simple_mutex_unlock(mtx);
                 continue;
             }
             break;
-        } while(TRUE);
+        } while(true);
 
         for (i=0; i<NTHR; i++) {
             pthread_join(thr[i]->tid, NULL);
@@ -504,7 +507,7 @@ static void* thr_run(
         skygw_logmanager_init( 0, NULL);
         skygw_logmanager_init( 0, NULL);
         skygw_logmanager_done();
-        simple_mutex_lock(td->mtx, TRUE);
+        simple_mutex_lock(td->mtx, true);
         *td->nactive -= 1;
         simple_mutex_unlock(td->mtx);
         skygw_message_send(td->mes);
@@ -557,7 +560,7 @@ static void* thr_run_morelog(
                                   str,
                                   i);
         }
-        simple_mutex_lock(td->mtx, TRUE);
+        simple_mutex_lock(td->mtx, true);
         *td->nactive -= 1;
         simple_mutex_unlock(td->mtx);
         skygw_message_send(td->mes);        
diff --git a/utils/skygw_utils.cc b/utils/skygw_utils.cc
index 516f7bb0d..ef638b10b 100644
--- a/utils/skygw_utils.cc
+++ b/utils/skygw_utils.cc
@@ -1321,6 +1321,12 @@ int simple_mutex_lock(
 {
         int err;
 
+        /**
+         * Leaving the following serves as a reminder. It may assert
+         * any given time because sm_lock_thr is not protected.
+         *
+         * ss_dassert(sm->sm_lock_thr != pthread_self());
+         */
         if (block) {
                 err = pthread_mutex_lock(&sm->sm_mutex);
         } else {
@@ -1336,6 +1342,9 @@ int simple_mutex_lock(
                         strerror(errno));
                 perror("simple_mutex : ");
         } else {
+                /**
+                 * Note that these updates are not protected.
+                 */
                 sm->sm_locked = true;
                 sm->sm_lock_thr = pthread_self();
         }
@@ -1346,18 +1355,27 @@ int simple_mutex_unlock(
         simple_mutex_t* sm)
 {
         int err;
-
+        /**
+         * Leaving the following serves as a reminder. It may assert
+         * any given time because sm_lock_thr is not protected.
+         *
+         * ss_dassert(sm->sm_lock_thr == pthread_self());
+         */
         err = pthread_mutex_unlock(&sm->sm_mutex);
 
         if (err != 0) {
                 fprintf(stderr,
-                        "* Locking simple mutex %s failed due error "
+                        "* Unlocking simple mutex %s failed due error "
                         "%d, %s\n",
                         sm->sm_name, 
                         err,
                         strerror(errno));
                 perror("simple_mutex : ");
+                ss_dassert(sm->sm_mutex.__data.__nusers >= 0);
         } else {
+                /**
+                 * Note that these updates are not protected.
+                 */
                 sm->sm_locked = false;
                 sm->sm_lock_thr = 0;
         }