https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64478
--- Comment #1 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
I found this initially with TSAN:
RUN c52104x
^M
,.,. C52104X ACATS 2.5 15-01-03 04:12:21^M
---- C52104X CHECK THAT IN ARRAY ASSIGNMENTS AND IN SLICE ASSIGNMENTS,^M
THE LENGTHS MUST MATCH; ALSO CHECK WHETHER^M
CONSTRAINT_ERROR OR STORAGE_ERROR ARE RAISED FOR LARGE^M
ARRAYS.^M
- C52104X NO CONSTRAINT_ERROR FOR TYPE WITH 'LENGTH = INTEGER'LAST + ^M
3.^M
==================^M
^[[1m^[[31mWARNING: ThreadSanitizer: signal-unsafe call inside of a signal
(pid=9681)^M
^[[1m^[[0m #0 malloc
../../../../gcc-trunk/libsanitizer/tsan/tsan_interceptors.cc:491
(libtsan.so.0+0x000000025c33)^M
#1 __gnat_malloc /home/ed/gnu/gcc-build/gcc/ada/rts/s-memory.adb:92
(c52104x+0x000000407070)^M
#2 main <null> (c52104x+0x000000402f93)^M
^M
SUMMARY: ThreadSanitizer: signal-unsafe call inside of a signal
/home/ed/gnu/gcc-build/gcc/ada/rts/s-memory.adb:92 __gnat_malloc^M
==================^M
- C52104X STORAGE_ERROR RAISED WHEN DECLARING TWO PACKED BOOLEAN^M
ARRAYS WITH INTEGER'LAST + 3 COMPONENTS.^M
==================^M
^[[1m^[[31mWARNING: ThreadSanitizer: signal-unsafe call inside of a signal
(pid=9681)^M
^[[1m^[[0m #0 free
../../../../gcc-trunk/libsanitizer/tsan/tsan_interceptors.cc:538
(libtsan.so.0+0x000000025f29)^M
#1 __gnat_free /home/ed/gnu/gcc-build/gcc/ada/rts/s-memory.adb:113
(c52104x+0x0000004070c1)^M
#2 main <null> (c52104x+0x000000402f93)^M
^M
SUMMARY: ThreadSanitizer: signal-unsafe call inside of a signal
/home/ed/gnu/gcc-build/gcc/ada/rts/s-memory.adb:113 __gnat_free^M
==================^M
==== C52104X PASSED ============================.^M
ThreadSanitizer: reported 2 warnings^M
PASS: c52104x
