From 83b2105241e925b14f1d7dfdb883c2c874fd391d Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Wed, 26 Sep 2018 14:56:11 -0700
Subject: [PATCH] StaticProvider createChannel() avoid possible deadlock

connect() may invoke SharedPV onFirstConnect() callback.
---
 src/server/server.cpp | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/server/server.cpp b/src/server/server.cpp
index ba4867e..7e64650 100644
--- a/src/server/server.cpp
+++ b/src/server/server.cpp
@@ -87,12 +87,17 @@ struct StaticProvider::Impl : public pva::ChannelProvider
         pva::Channel::shared_pointer ret;
         pvd::Status sts;
 
+        builders_t::mapped_type builder;
         {
             Guard G(mutex);
             builders_t::const_iterator it(builders.find(name));
-            if(it!=builders.end())
-                ret = it->second->connect(Impl::shared_pointer(internal_self), name, requester);
+            if(it!=builders.end()) {
+                UnGuard U(G);
+                builder = it->second;
+            }
         }
+        if(builder)
+            ret = builder->connect(Impl::shared_pointer(internal_self), name, requester);
 
         if(!ret) {
             sts = pvd::Status::error("No such channel");