From 80b6f9b0cb46666a14d471248cc3747930a28dd4 Mon Sep 17 00:00:00 2001
From: Dave-in-lafayette <64047859+Dave-in-lafayette@users.noreply.github.com>
Date: Mon, 20 Apr 2020 16:38:06 -0700
Subject: [PATCH] fix for crash during panic before all threads are up

If there's a panic before all threads have been started (say, if file descriptor 0 is closed at exec), the panic response will crash here again.
---
 src/bio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/bio.c b/src/bio.c
index 0662c8c4c..85f681185 100644
--- a/src/bio.c
+++ b/src/bio.c
@@ -266,7 +266,7 @@ void bioKillThreads(void) {
     int err, j;
 
     for (j = 0; j < BIO_NUM_OPS; j++) {
-        if (pthread_cancel(bio_threads[j]) == 0) {
+        if (bio_threads[j] && pthread_cancel(bio_threads[j]) == 0) {
             if ((err = pthread_join(bio_threads[j],NULL)) != 0) {
                 serverLog(LL_WARNING,
                     "Bio thread for job type #%d can be joined: %s",