Index: /trunk/source/lisp-kernel/lisp-debug.c
===================================================================
--- /trunk/source/lisp-kernel/lisp-debug.c	(revision 14259)
+++ /trunk/source/lisp-kernel/lisp-debug.c	(revision 14260)
@@ -1034,5 +1034,5 @@
 #ifdef X8664
 #ifdef LINUX
-  struct _libc_xmmreg * xmmp = &(xp->uc_mcontext.fpregs->_xmm[0]);
+  struct _libc_xmmreg * xmmp = NULL;
 #endif
 #ifdef DARWIN
@@ -1056,4 +1056,11 @@
   float *sp;
 
+#ifdef LINUX
+  if (xp->uc_mcontext.fpregs)
+    xmmp = &(xp->uc_mcontext.fpregs->_xmm[0]);
+  else
+    /* no fp state, apparently */
+    return debug_continue;
+#endif
 
   for (i = 0; i < 16; i++, xmmp++) {