diff --git a/mariadb-10.5-fix-prevent-optimizing-out-buf-argument-in-ch.patch b/mariadb-10.5-fix-prevent-optimizing-out-buf-argument-in-ch.patch
new file mode 100644
index 0000000..5b7d471
--- /dev/null
+++ b/mariadb-10.5-fix-prevent-optimizing-out-buf-argument-in-ch.patch
@@ -0,0 +1,40 @@
+From 35c277851972267d4d020126ab8f893c4b17dd36 Mon Sep 17 00:00:00 2001
+From: Martin Liska <mliska@suse.cz>
+Date: Sun, 8 Dec 2019 10:52:27 +0100
+Subject: [PATCH] MDEV-21248: Prevent optimizing out buf argument in
+ check_stack_overrun.
+
+When using LTO, one can see optimization of stack variables that
+are passed to check_stack_overrun as argument buf. That prevents
+proper stack overrun detection.
+---
+ sql/sql_parse.cc | 13 +++++++++++--
+ 1 file changed, 11 insertions(+), 2 deletions(-)
+
+diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
+index dc81e8a2b91..6f3c076709a 100644
+--- a/sql/sql_parse.cc
++++ b/sql/sql_parse.cc
+@@ -7392,8 +7392,17 @@ long max_stack_used;
+     corresponding exec. (Thus we only have to check in fix_fields.)
+   - Passing to check_stack_overrun() prevents the compiler from removing it.
+ */
+-bool check_stack_overrun(THD *thd, long margin,
+-			 uchar *buf __attribute__((unused)))
++
++bool
++#ifdef __GNUC__
++/*
++  Do not optimize the function in order to preserve a stack variable creation.
++  Otherwise, the variable pointed as "buf" can be removed due to a missing
++  usage.
++ */
++__attribute__((optimize("-O0")))
++#endif
++check_stack_overrun(THD *thd, long margin, uchar *buf __attribute__((unused)))
+ {
+   long stack_used;
+   DBUG_ASSERT(thd == current_thd);
+-- 
+2.25.1
+
diff --git a/mariadb.changes b/mariadb.changes
index 5686905..983ed22 100644
--- a/mariadb.changes
+++ b/mariadb.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Tue Mar 24 05:46:49 UTC 2020 - Martin Liška <mliska@suse.cz>
+
+- Add mariadb-10.5-fix-prevent-optimizing-out-buf-argument-in-ch.patch
+  in order to fix boo#1158405 (MDEV-21248).
+
 -------------------------------------------------------------------
 Wed Feb 26 16:25:55 UTC 2020 - Thorsten Kukuk <kukuk@suse.com>
 
diff --git a/mariadb.spec b/mariadb.spec
index 673fcbd..c01248f 100644
--- a/mariadb.spec
+++ b/mariadb.spec
@@ -84,6 +84,7 @@ Patch8:         mariadb-10.2.4-fortify-and-O.patch
 Patch9:         mariadb-10.2.19-link-and-enable-c++11-atomics.patch
 Patch10:        mariadb-10.4.12-harden_setuid.patch
 Patch11:        mariadb-10.4.12-fix-install-db.patch
+Patch12:        mariadb-10.5-fix-prevent-optimizing-out-buf-argument-in-ch.patch
 # needed for bison SQL parser and wsrep API
 BuildRequires:  bison
 BuildRequires:  cmake
@@ -370,6 +371,7 @@ find . -name "*.jar" -type f -exec rm --verbose -f {} \;
 %patch9 -p1
 %patch10 -p1
 %patch11 -p1
+%patch12 -p1
 
 cp %{_sourcedir}/suse-test-run .