From 7cb865527709cea8d7ebdd8e74f5e873fd132062 Mon Sep 17 00:00:00 2001
From: Nathan Brei <nbrei@jlab.org>
Date: Thu, 12 Dec 2024 00:04:44 -0500
Subject: [PATCH] Warm up backtrace()

---
 src/libraries/JANA/CLI/JSignalHandler.cc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/libraries/JANA/CLI/JSignalHandler.cc b/src/libraries/JANA/CLI/JSignalHandler.cc
index 2ef87f4d8..dfb019b5c 100644
--- a/src/libraries/JANA/CLI/JSignalHandler.cc
+++ b/src/libraries/JANA/CLI/JSignalHandler.cc
@@ -71,6 +71,13 @@ void register_handlers(JApplication* app) {
     // It would be nice to do this in a less unexpected place, and hopefully that will naturally
     // emerge from future refactorings.
 
+    // We capture a dummy backtrace to warm it up before it gets called inside a signal handler.
+    // Because backtrace() dynamically loads libgcc, calling malloc() in the process, it is not
+    // async-signal-safe until this warmup has happened. Thus we prevent a rare deadlock and several
+    // TSAN and Helgrind warnings.
+    JBacktrace backtrace;
+    backtrace.Capture();
+
     //Define signal action
     struct sigaction sSignalAction;
     sSignalAction.sa_sigaction = handle_sigsegv;