From 1e7c541b2f332daf5fb1c35a0b3f7d15cd0e36bc Mon Sep 17 00:00:00 2001
From: Andy Wingo <wingo@pobox.com>
Date: Sat, 22 Sep 2018 17:31:14 +0200
Subject: [PATCH] Fix case where running abort hook could trash registers

* libguile/vm-engine.c (abort): If the abort doesn't need to longjmp and
  the abort hook was enabled, cache registers first to avoid restoring
  a bad IP to the VM.
---
 libguile/vm-engine.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libguile/vm-engine.c b/libguile/vm-engine.c
index 4e0ef77ec..542cac413 100644
--- a/libguile/vm-engine.c
+++ b/libguile/vm-engine.c
@@ -1118,14 +1118,17 @@ VM_NAME (scm_thread *thread)
          intervening C frames to jump over, so we just continue
          directly.  */
 
+      CACHE_REGISTER ();
       ABORT_HOOK ();
 
 #if ENABLE_JIT
       if (mcode && !VP->disable_mcode)
-        scm_jit_enter_mcode (thread, mcode);
+        {
+          scm_jit_enter_mcode (thread, mcode);
+          CACHE_REGISTER ();
+        }
 #endif
 
-      CACHE_REGISTER ();
       NEXT (0);
     }