[Bug fortran/94788] New: Severe regression leading to double free in tcache

[juergen.reuter at desy dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94788

            Bug ID: 94788
           Summary: Severe regression leading to double free in tcache
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: juergen.reuter at desy dot de
  Target Milestone: ---

Unfortunately, just a week or so before the release there was a very severe
regression, which leads to a double free corruption in tcache, cf. below.
Unfortunately, it is tough to come up with a short reproducer because the case
where we see this problem is where our program (written in Fortran) generates
code, compiles it, links it, and runs it. Our code is rather large, and needs
OCaml to generate a reproducer. The code can be found here:
https://whizard.tp.nt.uni-siegen.de/
(nightly snapshot). As I said, to build it, you'd need OCaml, then do 
configure, make, make check. 
make check runs first in the subpackages circe2, omega, vamp, and then
in tests/unit_tests
There, the test simulations fails in its 10th sub-test with the corruption
below. 


free(): double free detected in tcache 2

Program received signal SIGABRT: Process abort signal.

Backtrace for this error:
#0  0x7f27812c6ba0 in ???
#1  0x7f27812c5df5 in ???
#2  0x7f2780f2583f in ???
#3  0x7f2780f257bb in ???
#4  0x7f2780f10534 in ???
#5  0x7f2780f67507 in ???
#6  0x7f2780f6dc19 in ???
#7  0x7f2780f6f6fc in ???
#8  0x545539 in __simulations_uti_MOD_simulations_10
        at
/builds/whizard/development/build/src/whizard-core/simulations_uti.f90:1239
#9  0x7f278209cec9 in __unit_tests_MOD_test
        at /builds/whizard/development/build/src/testing/unit_tests.f90:175
#10  0x522c12 in __simulations_ut_MOD_simulations_test
        at
/builds/whizard/development/build/src/whizard-core/simulations_ut.f90:72
#11  0x43e2cd in whizard_check
        at /builds/whizard/development/build/src/whizard-core/main_ut.f90:715
#12  0x43e2cd in main_ut
        at /builds/whizard/development/build/src/whizard-core/main_ut.f90:303
#13  0x4335ae in main
        at /builds/whizard/development/build/src/whizard-core/main_ut.f90:31
Aborted (core dumped)
FAIL simulations.run (exit status: 134)