From 350b4b34f460b91b8fa8f692cf6bc30d561a5711 Mon Sep 17 00:00:00 2001
From: Luca Boccassi <bluca@debian.org>
Date: Sun, 28 Jun 2020 13:36:57 +0100
Subject: [PATCH] Problem: test_security_zap occasionally segfaults

Solution: check if a session's _pipe has been allocated before using
it, since as a consequence of creating the pipes after the handshake
it's no longer guaranteed to be there.

Fixes #3971
---
 src/session_base.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/session_base.cpp b/src/session_base.cpp
index b7da4ccc71..551ae318f3 100644
--- a/src/session_base.cpp
+++ b/src/session_base.cpp
@@ -308,7 +308,8 @@ void zmq::session_base_t::read_activated (pipe_t *pipe_)
     }
 
     if (unlikely (_engine == NULL)) {
-        _pipe->check_read ();
+        if (_pipe)
+            _pipe->check_read ();
         return;
     }