Copied from Fedora.

https://bugzilla.redhat.com/show_bug.cgi?id=1232265
http://pkgs.fedoraproject.org/cgit/libunwind.git/tree/libunwind-1.1-fix-CVE-2015-3239.patch

diff -up libunwind-1.1/include/dwarf_i.h.CVE20153239 libunwind-1.1/include/dwarf_i.h
--- libunwind-1.1/include/dwarf_i.h.CVE20153239	2015-07-10 13:38:36.404996748 -0400
+++ libunwind-1.1/include/dwarf_i.h	2015-07-10 13:39:25.050707613 -0400
@@ -20,7 +20,7 @@
 extern const uint8_t dwarf_to_unw_regnum_map[DWARF_REGNUM_MAP_LENGTH];
 /* REG is evaluated multiple times; it better be side-effects free!  */
 # define dwarf_to_unw_regnum(reg)					  \
-  (((reg) <= DWARF_REGNUM_MAP_LENGTH) ? dwarf_to_unw_regnum_map[reg] : 0)
+  (((reg) < DWARF_REGNUM_MAP_LENGTH) ? dwarf_to_unw_regnum_map[reg] : 0)
 #endif
 
 #ifdef UNW_LOCAL_ONLY
