Fixed nxt_conn_accept_alloc() behavior in low memory conditions.

Earlier, if nxt_mp_create() failed to allocate memory while accepting a new
connection, the resulting NULL was subsequently passed to nxt_mp_destroy(),
crashing the process.

More, if nxt_mp_create() was successful but nxt_sockaddr_cache_alloc() failed,
the connection object wasn't destroyed properly, leaving the connection counter
in an inconsistent state.  Repeated, this condition lowered the connection
capacity of the process and could eventually prevent it from accepting
connections altogether.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/nxt_conn_accept.c b/src/nxt_conn_accept.c
index 6a89840c..77c44c58 100644
--- a/src/nxt_conn_accept.c
+++ b/src/nxt_conn_accept.c
@@ -98,7 +98,9 @@ nxt_conn_accept_alloc(nxt_task_t *task, nxt_listen_event_t *lev)
         if (nxt_fast_path(mp != NULL)) {
             c = nxt_conn_create(mp, lev->socket.task);
             if (nxt_slow_path(c == NULL)) {
-                goto fail;
+                nxt_mp_destroy(mp);
+
+                return NULL;
             }
 
             c->socket.read_work_queue = lev->socket.read_work_queue;
@@ -109,11 +111,9 @@ nxt_conn_accept_alloc(nxt_task_t *task, nxt_listen_event_t *lev)
                 lev->next = c;
                 return c;
             }
-        }
 
-    fail:
-
-        nxt_mp_destroy(mp);
+            nxt_conn_free(task, c);
+        }
     }
 
     return NULL;