[Bug fortran/108109] [ICE] gfortran compilation fails calling 'free()' with 'malloc(): mismatching next->prev_size (unsorted)'

["burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108109

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Created attachment 54096
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54096&action=edit
valgrind output.

(In reply to anlauf from comment #1)
> Is this attached file to be preprocessed?  Or does it need special options?
> Can't reproduce here.

I attached the valgrind output (for mainline) and the message fits to what
glibc diagnoses. There is simply an invalid READ – and the free is for a bogus
address (in the middle of an allocation).

As it is for a code which completely fails to compile, I don't think it is of
any priority at all - but I did not want to leave it unreported. (Main issue:
Several macros not defined, especially those which should expand to a string
literal.)

 * * *

Special option: In principle not, but for the main test file, I see differences
with and without '-cpp' and not a clear pattern. In particular:

No - it isn't. I just run: 'gcc-7 test.f90' (works), gcc-8 ... (works), gcc-9
(glibc's fatal message), gcc-10 (likewise), gcc-10/11/12 (works), mainline
(glibc's message).

Here, gcc-7 to gcc-10 are the Ubuntu version, gcc-11 to mainline are self
compiled. I checked and I don't have _MALLOC_PERTURB set.

The big program (MM_GPU_Library_Module.f90), I currently get the message with
'gfortran-9' with and without '-cpp' – but with gfortran mainline, I only get
it with -cpp. – I think I got it in different variants also before.

That's with Ubuntu 20.04.5 LTS + glibc 2.31-0ubuntu9.9.

(Often using something like MALLOC_PERTURB_=... helps, but here it doesn't;
probably because calloc and free are involved.)