https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88899
--- Comment #1 from martin <mscfd at gmx dot net> ---
With sufficiently many threads (at least 5 or 6 for me) the address santizer
gives (for gfortran-9, compiled a few weeks ago):
==3485==ERROR: AddressSanitizer: attempting double-free on 0x6020001956d0 in
thread T4:
#0 0x7f72705a7280 in __interceptor_free (/usr/lib64/libasan.so.5+0xeb280)
#1 0x401935 in __mod_MOD___final_mod_T
/home/mstein/code/forcomp_bugs/dt_io_2.f90:43
#2 0x402fb1 in __mod_MOD_work /home/mstein/code/forcomp_bugs/dt_io_2.f90:21
#3 0x40362a in MAIN__._omp_fn.0
/home/mstein/code/forcomp_bugs/dt_io_2.f90:56
#4 0x7f726faeb83d (/usr/lib64/libgomp.so.1+0x1783d)
#5 0x7f726f465558 in start_thread (/lib64/libpthread.so.0+0x7558)
#6 0x7f726f19c81e in __GI___clone (/lib64/libc.so.6+0xf881e)
0x6020001956d0 is located 0 bytes inside of 8-byte region
[0x6020001956d0,0x6020001956d8)
freed by thread T2 here:
#0 0x7f72705a7280 in __interceptor_free (/usr/lib64/libasan.so.5+0xeb280)
#1 0x401935 in __mod_MOD___final_mod_T
/home/mstein/code/forcomp_bugs/dt_io_2.f90:43
#2 0x402fb1 in __mod_MOD_work /home/mstein/code/forcomp_bugs/dt_io_2.f90:21
#3 0x40362a in MAIN__._omp_fn.0
/home/mstein/code/forcomp_bugs/dt_io_2.f90:56
#4 0x7f726faeb83d (/usr/lib64/libgomp.so.1+0x1783d)
previously allocated by thread T2 here:
#0 0x7f72705a7600 in malloc (/usr/lib64/libasan.so.5+0xeb600)
#1 0x402a17 in __mod_MOD_set /home/mstein/code/forcomp_bugs/dt_io_2.f90:29
#2 0x4032a0 in __mod_MOD_work /home/mstein/code/forcomp_bugs/dt_io_2.f90:23
#3 0x40362a in MAIN__._omp_fn.0
/home/mstein/code/forcomp_bugs/dt_io_2.f90:56
#4 0x7f726faeb83d (/usr/lib64/libgomp.so.1+0x1783d)
Thread T4 created by T0 here:
#0 0x7f7270508620 in pthread_create (/usr/lib64/libasan.so.5+0x4c620)
#1 0x7f726faebe39 (/usr/lib64/libgomp.so.1+0x17e39)
#2 0x7f726fae2d59 in GOMP_parallel (/usr/lib64/libgomp.so.1+0xed59)
Thread T2 created by T0 here:
#0 0x7f7270508620 in pthread_create (/usr/lib64/libasan.so.5+0x4c620)
#1 0x7f726faebe39 (/usr/lib64/libgomp.so.1+0x17e39)
#2 0x7f726fae2d59 in GOMP_parallel (/usr/lib64/libgomp.so.1+0xed59)
SUMMARY: AddressSanitizer: double-free (/usr/lib64/libasan.so.5+0xeb280) in
__interceptor_free
==3485==ABORTING
