diff --git a/src/core/ngx_log.h b/src/core/ngx_log.h
index 9919fa8..2d7f2e9 100644
--- a/src/core/ngx_log.h
+++ b/src/core/ngx_log.h
@@ -207,6 +207,23 @@
 #endif
 
 #if (NGX_DEBUG)
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, arg1, arg2, arg3, arg4)
+#else
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4)
+#endif
+
+#if (NGX_DEBUG)
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5) \
+    if (log->log_level & level) \
+        ngx_log_error_core(NGX_LOG_DEBUG, log, err, fmt, \
+                           arg1, arg2, arg3, arg4, arg5)
+#else
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5)
+#endif
+
+#if (NGX_DEBUG)
 #define ngx_log_debug6(level, log, err, fmt, \
                        arg1, arg2, arg3, arg4, arg5, arg6) \
     if (log->log_level & level) \
@@ -253,6 +270,22 @@
 #endif
 
 #if (NGX_DEBUG)
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4)
+#else
+#define ngx_log_debug4(level, log, err, fmt, arg1, arg2, arg3, arg4)
+#endif
+
+#if (NGX_DEBUG)
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5) \
+    if (log->log_level & level) \
+        ngx_log_debug_core(log, err, fmt, arg1, arg2, arg3, arg4, arg5)
+#else
+#define ngx_log_debug5(level, log, err, fmt, arg1, arg2, arg3, arg4, arg5)
+#endif
+
+#if (NGX_DEBUG)
 #define ngx_log_debug6(level, log, err, fmt, \
                        arg1, arg2, arg3, arg4, arg5, arg6) \
     if (log->log_level & level) \
diff --git a/src/event/ngx_event_timer.h b/src/event/ngx_event_timer.h
index cb61f36..69de163 100644
--- a/src/event/ngx_event_timer.h
+++ b/src/event/ngx_event_timer.h
@@ -33,15 +33,24 @@
 extern ngx_rbtree_t   ngx_event_timer_sentinel;
 
 
+#define ngx_event_ident(p)  ((ngx_connection_t *) (p))->fd
+
 
 ngx_inline static void ngx_event_del_timer(ngx_event_t *ev)
 {
-    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0,
-                   "event timer del: %d", ev->rbtree_key);
+    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
+                   "event timer del: %d: %d",
+                    ngx_event_ident(ev->data), ev->rbtree_key);
 
     ngx_rbtree_delete(&ngx_event_timer_rbtree, &ngx_event_timer_sentinel,
                       (ngx_rbtree_t *) &ev->rbtree_key);
 
+#if (NGX_DEBUG)
+    ev->rbtree_left = NULL;
+    ev->rbtree_right = NULL;
+    ev->rbtree_parent = NULL;
+#endif
+
     ev->timer_set = 0;
 }
 
@@ -59,8 +68,9 @@
                              (ngx_elapsed_msec + timer) / NGX_TIMER_RESOLUTION;
 #endif
 
-    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0,
-                   "event timer add: %d", ev->rbtree_key);
+    ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0,
+                   "event timer add: %d: %d",
+                    ngx_event_ident(ev->data), ev->rbtree_key);
 
     ngx_rbtree_insert(&ngx_event_timer_rbtree, &ngx_event_timer_sentinel,
                       (ngx_rbtree_t *) &ev->rbtree_key);
diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index 396e282..9408fc8 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -657,6 +657,24 @@
 
             /* there was error while a header line parsing */
 
+#if (NGX_LOG_DEBUG)
+            if (rc == NGX_HTTP_PARSE_INVALID_HEADER) {
+                char  *p;
+                for (p = r->header_name_start;
+                     p < r->header_in->last - 1;
+                     p++)
+                {
+                    if (*p == CR || *p == LF) {
+                        break;
+                    }
+                }
+                *p = '\0';
+                ngx_log_debug1(NGX_LOG_DEBUG_HTTP, rev->log, 0,
+                               "http invalid header: \"%s\"",
+                               r->header_name_start);
+            }
+#endif
+
             ngx_http_client_error(r, rc, NGX_HTTP_BAD_REQUEST);
             return;
         }
@@ -1419,7 +1437,7 @@
         return;
     }
 
-    if (error) {
+    if (error && r->headers_out.status == 0) {
         r->headers_out.status = error;
     }
 
diff --git a/src/os/unix/ngx_freebsd_sendfile_chain.c b/src/os/unix/ngx_freebsd_sendfile_chain.c
index c9d3d7a..6ca15fb 100644
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -44,7 +44,7 @@
 #if (HAVE_KQUEUE)
 
     if ((ngx_event_flags & NGX_HAVE_KQUEUE_EVENT) && wev->kq_eof) {
-        ngx_log_error(NGX_LOG_ERR, c->log, wev->kq_errno,
+        ngx_log_error(NGX_LOG_INFO, c->log, wev->kq_errno,
                       "kevent() reported about closed connection");
 
         wev->error = 1;
@@ -153,7 +153,7 @@
             if (ngx_freebsd_use_tcp_nopush && !c->tcp_nopush) {
                 c->tcp_nopush = 1;
 
-ngx_log_debug(c->log, "NOPUSH");
+                ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, 0, "tcp_nopush");
 
                 if (ngx_tcp_nopush(c->fd) == NGX_ERROR) {
                     ngx_log_error(NGX_LOG_CRIT, c->log, ngx_errno,
@@ -193,9 +193,9 @@
                 }
 
                 if (err == NGX_EAGAIN || err == NGX_EINTR) {
-                    ngx_log_error(NGX_LOG_INFO, c->log, err,
-                                  "sendfile() sent only " OFF_T_FMT " bytes",
-                                  sent);
+                    ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, err,
+                                   "sendfile() sent only " OFF_T_FMT " bytes",
+                                   sent);
 
                 } else {
                     wev->error = 1;
@@ -205,22 +205,23 @@
                 }
             }
 
-#if (NGX_DEBUG_WRITE_CHAIN)
-            ngx_log_debug(c->log, "sendfile: %d, @%qd %qd:%d" _
-                          rc _ file->file_pos _ sent _ fsize + hsize);
-#endif
+            ngx_log_debug4(NGX_LOG_DEBUG_EVENT, c->log, 0,
+                           "sendfile: %d, @" OFF_T_FMT " " OFF_T_FMT ":%d",
+                           rc, file->file_pos, sent, fsize + hsize);
 
         } else {
             rc = writev(c->fd, header.elts, header.nelts);
 
             if (rc == -1) {
                 err = ngx_errno;
-                if (err == NGX_EAGAIN) {
-                    ngx_log_error(NGX_LOG_INFO, c->log, err, "writev() EAGAIN");
 
-                } else if (err == NGX_EINTR) {
+                if (err == NGX_EINTR) {
                     eintr = 1;
-                    ngx_log_error(NGX_LOG_INFO, c->log, err, "writev() EINTR");
+                }
+
+                if (err == NGX_EAGAIN || err == NGX_EINTR) {
+                    ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
+                                   "writev() not ready");
 
                 } else {
                     wev->error = 1;
@@ -231,9 +232,8 @@
 
             sent = rc > 0 ? rc : 0;
 
-#if (NGX_DEBUG_WRITE_CHAIN)
-            ngx_log_debug(c->log, "writev: %qd" _ sent);
-#endif
+            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, c->log, 0,
+                           "writev: " OFF_T_FMT, sent);
         }
 
         c->sent += sent;