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From: "burnus at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug fortran/99529] libgfortran I/O: Data races related to new unit
 / new unit calls for I/O to strings
Date: Thu, 11 Mar 2021 09:31:43 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D99529

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to martin from comment #4)
> Ok, here is another suspicious data race in unit.c (backtrace from helgri=
nd):

It looks as if - for the libgfortran internal use - it first gets the unit
based on that number =E2=80=93 and then sets it again. Namely, the call is:

      unit =3D get_gfc_unit (dtp->common.unit, do_create);
      set_internal_unit (dtp, unit, kind);

Just to make sure, I add an assert - but I think the line can also be remov=
ed
for good.

--- a/libgfortran/io/unit.c
+++ b/libgfortran/io/unit.c
@@ -459 +459 @@ set_internal_unit (st_parameter_dt *dtp, gfc_unit *iunit, i=
nt
kind)
-  iunit->unit_number =3D dtp->common.unit;
+  assert (iunit->unit_number =3D=3D dtp->common.unit);=