From 64a6f69c926f4ed62e906bc37722ef4c1250237f Mon Sep 17 00:00:00 2001
From: Stefan Seifert <nine@detonation.org>
Date: Sat, 27 Jul 2019 18:13:39 +0200
Subject: [PATCH] Fix possible invalid memory access when throwing exceptions

---
 src/core/exceptions.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/core/exceptions.c b/src/core/exceptions.c
index b761b32157..2fcba85b63 100644
--- a/src/core/exceptions.c
+++ b/src/core/exceptions.c
@@ -599,7 +599,9 @@ MVMObject * MVM_exception_backtrace_strings(MVMThreadContext *tc, MVMObject *ex_
     else
         MVM_exception_throw_adhoc(tc, "Op 'backtracestrings' needs an exception object");
 
-    arr = MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTArray);
+    MVMROOT(tc, ex, {
+        arr = MVM_repr_alloc_init(tc, tc->instance->boot_types.BOOTArray);
+    });
     cur_frame = ex->body.origin;
 
     MVMROOT2(tc, arr, cur_frame, {