From 4ac4d5607214633f481beda8d7c24eec1803f1a7 Mon Sep 17 00:00:00 2001
From: DMG <dgreatwood@gmail.com>
Date: Thu, 29 Aug 2024 20:55:13 -0700
Subject: [PATCH] Fix: Lock interest_mutex_ When interest_ Modified in ctlEx

EventMethEpollEquivImpl::ctlEx now locks interest_mutex_ when
performing its add/mod/del actions.

Previously, the interest_mutex_ lock was released before these
add/mod/del actions were performed. This was confirmed to occasionally
cause a "use after free" in findEmEventInAnInterestSet (called out of
getReadyEmEvents) in another thread. It might also result in
corruption of the interest_ std::set.
---
 src/common/eventmeth.cc | 2 ++
 version.txt             | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/common/eventmeth.cc b/src/common/eventmeth.cc
index bd5b114c9..e49fd54da 100644
--- a/src/common/eventmeth.cc
+++ b/src/common/eventmeth.cc
@@ -4037,6 +4037,8 @@ EmEventTmrFd::EmEventTmrFd(clockid_t clock_id,
 
         if (ctl_res == 0)
         {
+            GUARD_AND_DBG_LOG(interest_mutex_);
+            
             switch(op)
             {
             case EvCtlAction::Add:
diff --git a/version.txt b/version.txt
index 36f87cbe5..57a3b2c0f 100644
--- a/version.txt
+++ b/version.txt
@@ -1 +1 @@
-0.4.1.20240828
+0.4.2.20240829