[Bug libgcc/61003] New: [4.9 Regression] Segfault in __deregister_frame_info_bases when exiting, on i686-mingw32 with dw2 unwinding

[fanael4 at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=61003

            Bug ID: 61003
           Summary: [4.9 Regression] Segfault in
                    __deregister_frame_info_bases when exiting, on
                    i686-mingw32 with dw2 unwinding
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: fanael4 at gmail dot com
            Target: i686-*-mingw32

When targeting i686-mingw32 all programs compiled with GCC with DWARF2
unwinding, including GCC itself, segfault when exiting. The segfaults are null
pointer references in __deregister_frame_info_bases, called from atexit handler
runner.

Tested on 4.9.1 r. 209891. Didn't test the trunk.

Backtrace (from Wine, on real Windows it's very similar):
#0  0x010b7810 in __deregister_frame_info_bases (begin=0x7ed5bb6f
<MSVCRT__cexit+127>) at ../../../../src/gcc/libgcc/unwind-dw2-fde.c:216
#1  0x05c2fd38 in ?? ()
#2  0x7ed5bb6f in MSVCRT__cexit () from /usr/bin/../lib32/wine/msvcrt.dll.so
#3  0x7ed5be3e in MSVCRT_exit () from /usr/bin/../lib32/wine/msvcrt.dll.so
#4  0x004014c3 in __tmainCRTStartup ()
#5  0x7b86041c in call_process_entry () from
/usr/bin/../lib32/wine/kernel32.dll.so
#6  0x7b861563 in ExitProcess () from /usr/bin/../lib32/wine/kernel32.dll.so
#7  0x7bc80490 in call_thread_func_wrapper () from
/usr/bin/../lib32/wine/ntdll.dll.so
#8  0x7bc834cf in call_thread_func () from /usr/bin/../lib32/wine/ntdll.dll.so
#9  0x7bc8046e in RtlRaiseException () from /usr/bin/../lib32/wine/ntdll.dll.so
#10 0x7bc53931 in call_dll_entry_point () from
/usr/bin/../lib32/wine/ntdll.dll.so
#11 0xf7559b6d in wine_call_on_stack () from /usr/bin/../lib32/libwine.so.1
#12 0xf7559c4e in wine_switch_to_stack () from /usr/bin/../lib32/libwine.so.1