diff --git a/CHANGES b/CHANGES
index 071e2ed187..4efd02a76a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,21 @@
+8.1.0-dev.612 | 2025-09-29 18:04:24 +0200
+
+  * Supervisor: Make last_signal atomic to squelch data race (Arne Welzel, Corelight)
+
+    When the stem process terminates and SIGCHLD is sent to the supervisor,
+    the signal might be handled by the main thread or any other threads that
+    aren't blocking SIGCHLD explicitly. Convert last_signal to a std::atomic<int>
+    such that non-main threads can safely set last_signal without triggering
+    data race as reported by TSAN. This doesn't make it less racy to work
+    last_signal, but it appears we only use it for debug printing anyhow and
+    another option might have been to just remove last_signal altogether.
+
+    Follow-up for #4849
+
+8.1.0-dev.610 | 2025-09-29 08:21:01 -0700
+
+  * Update docs submodule [nomail] (Tim Wojtulewicz, Corelight)
+
 8.1.0-dev.609 | 2025-09-29 13:08:15 +0200
 
   * cluster/zeromq: Fix Cluster::subscribe() block if not initialized (Arne Welzel, Corelight)
diff --git a/VERSION b/VERSION
index 4b178aee4a..2e45d2803d 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-8.1.0-dev.609
+8.1.0-dev.612
diff --git a/doc b/doc
index 2731def915..8f38ae2fd5 160000
--- a/doc
+++ b/doc
@@ -1 +1 @@
-Subproject commit 2731def9159247e6da8a3191783c89683363689c
+Subproject commit 8f38ae2fd563314393eb1ca58c827d26e9966520
diff --git a/src/supervisor/Supervisor.cc b/src/supervisor/Supervisor.cc
index 48894d1f0e..974367c87c 100644
--- a/src/supervisor/Supervisor.cc
+++ b/src/supervisor/Supervisor.cc
@@ -415,7 +415,7 @@ static ForkResult fork_with_stdio_redirect(const char* where) {
 
 void Supervisor::HandleChildSignal() {
     if ( last_signal >= 0 ) {
-        DBG_LOG(DBG_SUPERVISOR, "Supervisor received signal %d", last_signal);
+        DBG_LOG(DBG_SUPERVISOR, "Supervisor received signal %d", last_signal.load());
         last_signal = -1;
     }
 
diff --git a/src/supervisor/Supervisor.h b/src/supervisor/Supervisor.h
index c433c0536a..84c5595138 100644
--- a/src/supervisor/Supervisor.h
+++ b/src/supervisor/Supervisor.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include <sys/types.h>
+#include <atomic>
 #include <chrono>
 #include <map>
 #include <memory>
@@ -323,7 +324,7 @@ private:
 
     Config config;
     pid_t stem_pid;
-    int last_signal = -1;
+    std::atomic<int> last_signal = -1;
     std::unique_ptr<detail::PipePair> stem_pipe;
     detail::LineBufferedPipe stem_stdout;
     detail::LineBufferedPipe stem_stderr;