From 96c4f5ecfc64f2f4d5d467b7c56cbc02198b939c Mon Sep 17 00:00:00 2001
From: John Sully <john@csquare.ca>
Date: Mon, 17 Feb 2020 18:57:13 -0500
Subject: [PATCH] processEventsWhileBlocked not exception safe

Former-commit-id: 1ef187533c26bfa0c084a815b8b80de92ba1cf0b
---
 src/networking.cpp | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/src/networking.cpp b/src/networking.cpp
index 9d94f5171..803edb5ac 100644
--- a/src/networking.cpp
+++ b/src/networking.cpp
@@ -3065,6 +3065,7 @@ void unpauseClientsIfNecessary()
  *
  * The function returns the total number of events processed. */
 int processEventsWhileBlocked(int iel) {
+    serverAssert(GlobalLocksAcquired());
     int iterations = 4; /* See the function top-comment. */
     int count = 0;
 
@@ -3074,14 +3075,30 @@ int processEventsWhileBlocked(int iel) {
         serverAssert(c->flags & CLIENT_PROTECTED);
         c->lock.unlock();
     }
+
     aeReleaseLock();
-    while (iterations--) {
-        int events = 0;
-        events += aeProcessEvents(g_pserver->rgthreadvar[iel].el, AE_FILE_EVENTS|AE_DONT_WAIT);
-        events += handleClientsWithPendingWrites(iel);
-        if (!events) break;
-        count += events;
+    serverAssertDebug(!GlobalLocksAcquired());
+    try
+    {
+        while (iterations--) {
+            int events = 0;
+            events += aeProcessEvents(g_pserver->rgthreadvar[iel].el, AE_FILE_EVENTS|AE_DONT_WAIT);
+            events += handleClientsWithPendingWrites(iel);
+            if (!events) break;
+            count += events;
+        }
     }
+    catch (...)
+    {
+        // Caller expects us to be locked so fix and rethrow
+        AeLocker locker;
+        if (c != nullptr)
+            c->lock.lock();
+        locker.arm(c);
+        locker.release();
+        throw;
+    }
+    
     AeLocker locker;
     if (c != nullptr)
         c->lock.lock();