https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116885
Thomas Koenig <tkoenig at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |WAITING CC| |tkoenig at gcc dot gnu.org Last reconfirmed| |2024-09-29 Ever confirmed|0 |1 --- Comment #1 from Thomas Koenig <tkoenig at gcc dot gnu.org> --- I checked your program with current trunk and with the Ubuntu-supplied gcc 11.4.0, plus clang 14.0 - they all segfault. With current trunk, valgrind says <<<struct>>> (c)1998-2024 Jaroslav Fojtik This program tests the struct.c library ***LO_ENDIAN defined*** ***NATIVE access*** Testing struct manipulation ==690483== Invalid read of size 1 ==690483== at 0x48534F0: mempcpy (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so) ==690483== by 0x49E9664: _IO_new_file_xsputn (fileops.c:1235) ==690483== by 0x49E9664: _IO_file_xsputn@@GLIBC_2.2.5 (fileops.c:1196) ==690483== by 0x49DDFD6: fwrite (iofwrite.c:39) ==690483== by 0x402051: savestruct (struct.c:484) ==690483== by 0x40227B: SaveTopolHeader (mintest.c:50) ==690483== by 0x401277: main (mintest.c:143) ==690483== Address 0x654d2074726f6853 is not stack'd, malloc'd or (recently) free'd ==690483== ==690483== ==690483== Process terminating with default action of signal 11 (SIGSEGV) ==690483== General Protection Fault ==690483== at 0x48534F0: mempcpy (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so) ==690483== by 0x49E9664: _IO_new_file_xsputn (fileops.c:1235) ==690483== by 0x49E9664: _IO_file_xsputn@@GLIBC_2.2.5 (fileops.c:1196) ==690483== by 0x49DDFD6: fwrite (iofwrite.c:39) ==690483== by 0x402051: savestruct (struct.c:484) ==690483== by 0x40227B: SaveTopolHeader (mintest.c:50) ==690483== by 0x401277: main (mintest.c:143) I suspect there is an error in your reduced test case.