From d90ebb9f8599a286b3fe05e6bec48873e6c93eab 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: 45b711f9d124a948a66e667992176b5387943512
---
 src/networking.cpp | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/src/networking.cpp b/src/networking.cpp
index bbb24495c..242e69798 100644
--- a/src/networking.cpp
+++ b/src/networking.cpp
@@ -3183,6 +3183,7 @@ 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;
 
@@ -3194,12 +3195,25 @@ int processEventsWhileBlocked(int iel) {
     }
     aeReleaseLock();
     serverAssertDebug(!GlobalLocksAcquired());
-    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;
+    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)