diff --git a/src/os/unix/ngx_darwin_sendfile_chain.c b/src/os/unix/ngx_darwin_sendfile_chain.c
index ec247d21b..078d10b24 100644
--- a/src/os/unix/ngx_darwin_sendfile_chain.c
+++ b/src/os/unix/ngx_darwin_sendfile_chain.c
@@ -103,10 +103,8 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
         prev = NULL;
         iov = NULL;
 
-        for (cl = in;
-             cl && header.nelts < IOV_MAX && send < limit;
-             cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -125,6 +123,10 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += (size_t) size;
 
             } else {
+                if (header.nelts >= IOV_MAX) {
+                    break;
+                }
+
                 iov = ngx_array_push(&header);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;
@@ -178,7 +180,7 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
             prev = NULL;
             iov = NULL;
 
-            while (cl && header.nelts < IOV_MAX && send < limit) {
+            while (cl && send < limit) {
 
                 if (ngx_buf_special(cl->buf)) {
                     cl = cl->next;
@@ -199,6 +201,10 @@ ngx_darwin_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     iov->iov_len += (size_t) size;
 
                 } else {
+                    if (trailer.nelts >= IOV_MAX) {
+                        break;
+                    }
+
                     iov = ngx_array_push(&trailer);
                     if (iov == NULL) {
                         return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_freebsd_sendfile_chain.c b/src/os/unix/ngx_freebsd_sendfile_chain.c
index 724bb0d70..f58b5c20f 100644
--- a/src/os/unix/ngx_freebsd_sendfile_chain.c
+++ b/src/os/unix/ngx_freebsd_sendfile_chain.c
@@ -107,10 +107,8 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
         prev = NULL;
         iov = NULL;
 
-        for (cl = in;
-             cl && header.nelts < IOV_MAX && send < limit;
-             cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -129,6 +127,10 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += (size_t) size;
 
             } else {
+                if (header.nelts >= IOV_MAX){
+                    break;
+                }
+
                 iov = ngx_array_push(&header);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;
@@ -183,7 +185,7 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
             prev = NULL;
             iov = NULL;
 
-            while (cl && header.nelts < IOV_MAX && send < limit) {
+            while (cl && send < limit) {
 
                 if (ngx_buf_special(cl->buf)) {
                     cl = cl->next;
@@ -204,6 +206,10 @@ ngx_freebsd_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     iov->iov_len += (size_t) size;
 
                 } else {
+                    if (trailer.nelts >= IOV_MAX){
+                        break;
+                    }
+
                     iov = ngx_array_push(&trailer);
                     if (iov == NULL) {
                         return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_linux_sendfile_chain.c b/src/os/unix/ngx_linux_sendfile_chain.c
index 4f6fdf587..e8f3d5a89 100644
--- a/src/os/unix/ngx_linux_sendfile_chain.c
+++ b/src/os/unix/ngx_linux_sendfile_chain.c
@@ -89,10 +89,8 @@ ngx_linux_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 
         /* create the iovec and coalesce the neighbouring bufs */
 
-        for (cl = in;
-             cl && header.nelts < IOV_MAX && send < limit;
-             cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -132,6 +130,10 @@ ngx_linux_sendfile_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += (size_t) size;
 
             } else {
+                if (header.nelts >= IOV_MAX) {
+                    break;
+                }
+
                 iov = ngx_array_push(&header);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_solaris_sendfilev_chain.c b/src/os/unix/ngx_solaris_sendfilev_chain.c
index 64e59aa2e..f800c15f5 100644
--- a/src/os/unix/ngx_solaris_sendfilev_chain.c
+++ b/src/os/unix/ngx_solaris_sendfilev_chain.c
@@ -94,8 +94,8 @@ ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 
         /* create the sendfilevec and coalesce the neighbouring bufs */
 
-        for (cl = in; cl && vec.nelts < IOV_MAX && send < limit; cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -113,6 +113,10 @@ ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     sfv->sfv_len += (size_t) size;
 
                 } else {
+                    if (vec.nelts >= IOV_MAX) {
+                        break;
+                    }
+
                     sfv = ngx_array_push(&vec);
                     if (sfv == NULL) {
                         return NGX_CHAIN_ERROR;
@@ -147,6 +151,10 @@ ngx_solaris_sendfilev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                     sfv->sfv_len += (size_t) size;
 
                 } else {
+                    if (vec.nelts >= IOV_MAX) {
+                        break;
+                    }
+
                     sfv = ngx_array_push(&vec);
                     if (sfv == NULL) {
                         return NGX_CHAIN_ERROR;
diff --git a/src/os/unix/ngx_writev_chain.c b/src/os/unix/ngx_writev_chain.c
index a752b1f91..805982d65 100644
--- a/src/os/unix/ngx_writev_chain.c
+++ b/src/os/unix/ngx_writev_chain.c
@@ -71,8 +71,8 @@ ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
 
         /* create the iovec and coalesce the neighbouring bufs */
 
-        for (cl = in; cl && vec.nelts < IOV_MAX && send < limit; cl = cl->next)
-        {
+        for (cl = in; cl && send < limit; cl = cl->next) {
+
             if (ngx_buf_special(cl->buf)) {
                 continue;
             }
@@ -93,6 +93,10 @@ ngx_writev_chain(ngx_connection_t *c, ngx_chain_t *in, off_t limit)
                 iov->iov_len += size;
 
             } else {
+                if (vec.nelts >= IOV_MAX) {
+                    break;
+                }
+
                 iov = ngx_array_push(&vec);
                 if (iov == NULL) {
                     return NGX_CHAIN_ERROR;