diff --git a/.tsan-suppressions b/.tsan-suppressions
new file mode 100644
index 0000000000..8c85014a0a
--- /dev/null
+++ b/.tsan-suppressions
@@ -0,0 +1,10 @@
+# Suppressions for ThreadSanitizer (tsan).
+#
+# This file is used by setting the environment variable TSAN_OPTIONS to, e.g.,
+# "suppressions=$(pwd)/.tsan-suppressions". Observe that relative paths such as
+# ".tsan-suppressions" might not work.
+
+# A static variable is written to racily, but we always write the same value, so
+# in practice it (hopefully!) doesn't matter.
+race:^want_color$
+race:^transfer_debug$
diff --git a/color.c b/color.c
index 31b6207a00..9a9261ac16 100644
--- a/color.c
+++ b/color.c
@@ -338,6 +338,13 @@ static int check_auto_color(void)
 
 int want_color(int var)
 {
+	/*
+	 * NEEDSWORK: This function is sometimes used from multiple threads, and
+	 * we end up using want_auto racily. That "should not matter" since
+	 * we always write the same value, but it's still wrong. This function
+	 * is listed in .tsan-suppressions for the time being.
+	 */
+
 	static int want_auto = -1;
 
 	if (var < 0)
diff --git a/transport-helper.c b/transport-helper.c
index 33cff38cc0..2b830b2290 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -1117,6 +1117,13 @@ int transport_helper_init(struct transport *transport, const char *name)
 __attribute__((format (printf, 1, 2)))
 static void transfer_debug(const char *fmt, ...)
 {
+	/*
+	 * NEEDSWORK: This function is sometimes used from multiple threads, and
+	 * we end up using debug_enabled racily. That "should not matter" since
+	 * we always write the same value, but it's still wrong. This function
+	 * is listed in .tsan-suppressions for the time being.
+	 */
+
 	va_list args;
 	char msgbuf[PBUFFERSIZE];
 	static int debug_enabled = -1;