Hi Martin, On 10.03.21 21:40, mscfd via Fortran wrote:
Using helgrind on a simple omp do loop with write to a character variable, I get some possible data races in libgfortran/io/unit.c.
[...] Thanks for digging. I have filled https://gcc.gnu.org/PR99529
There global array newunits is allocated and possibly reallocated in "newunit_alloc". According to the lock outputs from helgrind I see that this routine is called even if output is into a character variable. [...]
Concur - I don't know why this is needed (it is clearly done in purpose), but I only know libgfortran's I/O superficially.
Could it be that the corresponding write routine in transfer.c which calls newunit_free does not obtain the necessary lock. I cannot find it (which does not count for much).
Glancing at the code, I came to the same conclusion (see patch in the linked PR). But I have not tried whether it helps. But at least it compiles. Thus, if you could test whether it helps on your side? Otherwise, I hope that Jerry chimes in. Tobias ----------------- Mentor Graphics (Deutschland) GmbH, Arnulfstrasse 201, 80634 München Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Frank Thürauf
