From 727252ff1bb65c7abddc5a9acb17304695c09265 Mon Sep 17 00:00:00 2001
From: Vladislav Vaintroub <wlad@mariadb.com>
Date: Sat, 20 Jun 2020 01:00:36 +0200
Subject: MDEV-22950 : fix race condition in dbug

FreeState() zeros init_settings.out_file, which another thread can be using
---
 dbug/dbug.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/dbug/dbug.c b/dbug/dbug.c
index 21f86ded0a5..b0e1b0eaae6 100644
--- a/dbug/dbug.c
+++ b/dbug/dbug.c
@@ -483,6 +483,7 @@ static int DbugParse(CODE_STATE *cs, const char *control)
   rel= control[0] == '+' || control[0] == '-';
   if ((!rel || (!stack->out_file && !stack->next)))
   {
+    LockIfInitSettings(cs);
     FreeState(cs, 0);
     stack->flags= 0;
     stack->delay= 0;
@@ -490,10 +491,9 @@ static int DbugParse(CODE_STATE *cs, const char *control)
     stack->sub_level= 0;
     stack->out_file= sstderr;
     stack->functions= NULL;
-    LockIfInitSettings(cs);
     stack->keywords= NULL;
-    UnlockIfInitSettings(cs);
     stack->processes= NULL;
+    UnlockIfInitSettings(cs);
   }
   else if (!stack->out_file)
   {
-- 
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