Fix at-limit race

2 files changed, 9 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index b400bb65..92dd8736 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,6 @@
+Tue Sep 26 14:00:58 CEST 2017
+        Fixing race involving setting "at_limit" flag. -CG
+
 Tue Sep 08 21:39:00 MSK 2017
         Fixed build of examples when MHD build with non-pthread lib.
         MHD_queue_response(): added check for using in correct thread.
@@ -19,7 +22,7 @@ Tue Jun 20 23:52:00 MSK 2017
         Libgcrypt is now optional and required only for old GnuTLS versions. -EG
 
 Wed Jun 14 21:42:00 MSK 2017
-        Added support for debug assert() and new configure parameter 
+        Added support for debug assert() and new configure parameter
         --enable-asserts for debug builds.
         Removed non-functional Symbian support. -EG
 
@@ -37,7 +40,7 @@ Mon Jun 05 23:34:00 MSK 2017
 Mon Jun 05 22:20:00 MSK 2017
         Internal refactoring:
         used TCP sockets directly with GnuTLS (performance improvement),
-        moved some connection-related code from daemon.c to 
+        moved some connection-related code from daemon.c to
         connection.c/connection_https.c,
         removed hacks around sendfile() and implemented correct support of
         sendfile(),
@@ -82,7 +85,7 @@ Thu May 11 14:24:00 MSK 2017
         Do not add any "Connection" headers for "upgrade" connections. -EG
 
 Wed May 10 23:09:00 MSK 2017
-        Resume resuming connection before other processing in external polling 
+        Resume resuming connection before other processing in external polling
         mode. -EG
 
 Tue May  9 23:16:00 MSK 2017
@@ -103,7 +106,7 @@ Mon May  8 19:30:00 MSK 2017
         MHD_get_response_header(), match only headers (not footers). -EG
 
 Fri May  5 20:57:00 MSK 2017
-        Fixed null dereference when connection has "Upgrade" request and 
+        Fixed null dereference when connection has "Upgrade" request and
         connection is not upgraded.  -JB/EG
         Better handle Keep-Alive/Close. -EG
 
diff --git a/src/microhttpd/daemon.c b/src/microhttpd/daemon.c
index 18bfc7a8..fb363caa 100644
--- a/src/microhttpd/daemon.c
+++ b/src/microhttpd/daemon.c
@@ -2910,7 +2910,9 @@ MHD_accept_connection (struct MHD_Daemon *daemon)
             }
           else
             {
+              MHD_mutex_lock_chk_ (&daemon->cleanup_connection_mutex);
               daemon->at_limit = true;
+              MHD_mutex_unlock_chk_ (&daemon->cleanup_connection_mutex);
 #ifdef HAVE_MESSAGES
               MHD_DLOG (daemon,
                         _("Hit process or system resource limit at %u connections, temporarily suspending accept(). Consider setting a lower MHD_OPTION_CONNECTION_LIMIT.\n"),