https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110987
Bug ID: 110987
Summary: Segmentation fault after finalization of a temporary
variable
Product: gcc
Version: 13.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: chilikin.k at gmail dot com
Target Milestone: ---
Created attachment 55720
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55720&action=edit
Test case
The attached test program works fine with gfortran 12.2.0 and crashes with
a segmentation fault when compiled with gfortran 13.2.0. The compilation
command is
gfortran -g -o test test.f90
The segmentation fault happens when the function T1_GET_NEXT() tries to access
SELF%NEXT(1)%T1, which is deallocated and overwritten:
$ valgrind ./test
==1651009== Invalid read of size 8
==1651009== at 0x40251D: __test_module_MOD_t1_get_next (in test)
==1651009== by 0x403678: MAIN__ (in test)
==1651009== by 0x4036D0: main (in test)
==1651009== Address 0x4e92d48 is 8 bytes inside a block of size 16 free'd
==1651009== at 0x48399AB: free (vg_replace_malloc.c:538)
==1651009== by 0x402876: __test_module_MOD_t1_destructor (in test)
==1651009== by 0x401812: __test_module_MOD___final_test_module_T1 (in test)
==1651009== by 0x4035CF: MAIN__ (in test)
==1651009== by 0x4036D0: main (in test)
==1651009== Block was alloc'd at
==1651009== at 0x483877F: malloc (vg_replace_malloc.c:307)
==1651009== by 0x4026AF: __test_module_MOD_t1_set_n_next (in test)
==1651009== by 0x402466: __test_module_MOD_t2_constructor (in test)
==1651009== by 0x402E93: MAIN__ (in test)
==1651009== by 0x4036D0: main (in test)
The corresponding part of the output of
$ objdump -S ./test | less
is attached. The final-subroutine call which incorrectly deallocates memory
happens at 4035cd, between the calls of __test_module_MOD_t3_constructor and
__test_module_MOD_t1_set_n_next. Thus, the finalization seems to happen for
the temporary variable allocated as the result of T3() call, which is assigned
then to X3, and the memory corresponding to
CLASS(T1_POINTER), ALLOCATABLE :: NEXT(:)
is probably the same for that temporary variable and X3 (in contradiction with
10.2.1.3.13 item (2) of Fortran 2018?).
May be related to the fix of bug 80524.
