diff --git a/src/mdbx.c b/src/mdbx.c
index 63c4b958..5182c2bf 100644
--- a/src/mdbx.c
+++ b/src/mdbx.c
@@ -3849,8 +3849,10 @@ static int mdbx_sync_locked(MDBX_env *env, unsigned flags,
     target = mdbx_meta_ancient(env, meta1, meta2, true);
   else if (head == meta1)
     target = mdbx_meta_ancient(env, meta0, meta2, true);
-  else if (head == meta2)
+  else {
+    mdbx_assert(env, head == meta2);
     target = mdbx_meta_ancient(env, meta0, meta1, true);
+  }
 
   /* LY: step#2 - update meta-page. */
   mdbx_debug(
@@ -4924,7 +4926,7 @@ int __cold mdbx_env_open_ex(MDBX_env *env, const char *path, unsigned flags,
     rc = mdbx_rthc_alloc(&env->me_txkey, &env->me_lck->mti_readers[0],
                          &env->me_lck->mti_readers[env->me_maxreaders]);
     if (unlikely(rc != MDBX_SUCCESS))
-      return rc;
+      goto bailout;
     env->me_flags |= MDBX_ENV_TXKEY;
   }
 
@@ -6190,6 +6192,7 @@ static int mdbx_cursor_first(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data) {
 
   if (likely(data)) {
     if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+      mdbx_cassert(mc, mc->mc_xcursor != nullptr);
       mdbx_xcursor_init1(mc, leaf);
       rc = mdbx_cursor_first(&mc->mc_xcursor->mx_cursor, data, NULL);
       if (unlikely(rc))
@@ -6233,6 +6236,7 @@ static int mdbx_cursor_last(MDBX_cursor *mc, MDBX_val *key, MDBX_val *data) {
 
   if (likely(data)) {
     if (F_ISSET(leaf->mn_flags, F_DUPDATA)) {
+      mdbx_cassert(mc, mc->mc_xcursor != nullptr);
       mdbx_xcursor_init1(mc, leaf);
       rc = mdbx_cursor_last(&mc->mc_xcursor->mx_cursor, data, NULL);
       if (unlikely(rc))
@@ -9653,7 +9657,7 @@ int __cold mdbx_env_info(MDBX_env *env, MDBX_envinfo *arg, size_t bytes) {
                     arg->me_recent_txnid != mdbx_meta_txnid_fluid(env, meta)));
 
   arg->me_maxreaders = env->me_maxreaders;
-  arg->me_numreaders = env->me_lck->mti_numreaders;
+  arg->me_numreaders = env->me_lck ? env->me_lck->mti_numreaders : INT32_MAX;
   arg->me_dxb_pagesize = env->me_psize;
   arg->me_sys_pagesize = env->me_os_psize;
 
@@ -10279,7 +10283,7 @@ int __cold mdbx_reader_check0(MDBX_env *env, int rdt_locked, int *dead) {
     /* stale reader found */
     if (!rdt_locked) {
       err = mdbx_rdt_lock(env);
-      if (MDBX_IS_ERROR(rc)) {
+      if (MDBX_IS_ERROR(err)) {
         rc = err;
         break;
       }
@@ -10296,7 +10300,7 @@ int __cold mdbx_reader_check0(MDBX_env *env, int rdt_locked, int *dead) {
         continue;
 
       err = mdbx_rpid_check(env, pid);
-      if (MDBX_IS_ERROR(rc)) {
+      if (MDBX_IS_ERROR(err)) {
         rc = err;
         break;
       }
diff --git a/src/osal.c b/src/osal.c
index 08ae9fef..ae28d191 100644
--- a/src/osal.c
+++ b/src/osal.c
@@ -549,7 +549,7 @@ int mdbx_write(mdbx_filehandle_t fd, const void *buf, size_t bytes) {
   sigset_t set, old;
   sigemptyset(&set);
   sigaddset(&set, SIGPIPE);
-  int rc = rc = pthread_sigmask(SIG_BLOCK, &set, &old);
+  int rc = pthread_sigmask(SIG_BLOCK, &set, &old);
   if (rc != 0)
     return rc;
 #endif
diff --git a/src/tools/mdbx_chk.c b/src/tools/mdbx_chk.c
index ad8f85c8..ccc0592b 100644
--- a/src/tools/mdbx_chk.c
+++ b/src/tools/mdbx_chk.c
@@ -229,7 +229,7 @@ static int pgvisitor(uint64_t pgno, unsigned pgnumber, void *ctx,
 
   if (type) {
     uint64_t page_bytes = payload_bytes + header_bytes + unused_bytes;
-    uint64_t page_size = pgnumber * envstat.ms_psize;
+    size_t page_size = (size_t)pgnumber * envstat.ms_psize;
     int index = pagemap_lookup_dbi(dbi);
     if (index < 0)
       return ENOMEM;
diff --git a/test/log.cc b/test/log.cc
index eee0fffe..5ab99513 100644
--- a/test/log.cc
+++ b/test/log.cc
@@ -125,9 +125,11 @@ bool output(const logging::loglevel priority, const char *format, va_list ap) {
   switch (end) {
   default:
     putc('\n', last);
+  // fall through
   case '\n':
     fflush(last);
     last = nullptr;
+  // fall through
   case ' ':
   case '_':
   case ':':
diff --git a/test/test.cc b/test/test.cc
index 50426014..9a265e33 100644
--- a/test/test.cc
+++ b/test/test.cc
@@ -76,9 +76,10 @@ static void mdbx_debug_logger(int type, const char *function, int line,
   if (type & MDBX_DBG_PRINT)
     level = logging::verbose;
 
+  if (!function)
+    function = "unknown";
   if (type & MDBX_DBG_ASSERT) {
-    log_error("mdbx: assertion failure: %s, %d",
-              function ? function : "unknown", line);
+    log_error("mdbx: assertion failure: %s, %d", function, line);
     level = logging::failure;
   }
 
diff --git a/test/test.h b/test/test.h
index 98b65801..0a9b8a38 100644
--- a/test/test.h
+++ b/test/test.h
@@ -136,7 +136,7 @@ protected:
 
 public:
   testcase(const actor_config &config, const mdbx_pid_t pid)
-      : config(config), pid(pid), nops_completed(0) {
+      : config(config), pid(pid), signalled(false), nops_completed(0) {
     start_timestamp.reset();
     memset(&last, 0, sizeof(last));
   }