From b2f3c5f4e799126b7ea1f74c4c9c26668dbdf6d8 Mon Sep 17 00:00:00 2001
From: James Foster <github@jgfoster.net>
Date: Fri, 8 May 2020 19:38:39 -0700
Subject: [PATCH] Use spinlock for logging to avoid interleaving output.

---
 k-hardware.cc | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/k-hardware.cc b/k-hardware.cc
index 92e7f1c..71b77f2 100644
--- a/k-hardware.cc
+++ b/k-hardware.cc
@@ -171,7 +171,11 @@ struct log_printer : public printer {
 };
 }
 
+// things get ugly when multiple processes output at the same time!
+static spinlock printLock;
+
 void log_vprintf(const char* format, va_list val) {
+    spinlock_guard guard(printLock);
     log_printer p;
     p.vprintf(0, format, val);
 }