https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100371
Bug ID: 100371
Summary: Fortran asynchronous I/O: ASAN (memory leak) + TASN
(potential dead lock) warning with
libgomp.fortran/async_io_*.f90
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: burnus at gcc dot gnu.org
CC: jb at gcc dot gnu.org, jvdelisle at gcc dot gnu.org
Depends on: 100352
Target Milestone: ---
Follow up to PR100352
Shows up in GCC 10 and mainline/12 when running libgomp.fortran/async_io_*.f90
with "gfortran -fopenmp" and ...
(A) -fsanitize=thread
WARNING: ThreadSanitizer: lock-order-inversion (potential deadlock)
(pid=2980290)
Mutex M25 acquired here while holding mutex M24 in main thread:
#2 insert_unit ../../../repos/gcc/libgfortran/io/unit.c:244 LOCK
(&u->lock);
Mutex M24 previously acquired by the same thread here:
#2 get_gfc_unit ../../../repos/gcc/libgfortran/io/unit.c:332 LOCK
(&unit_lock);
Mutex M24 acquired here while holding mutex M25 in main thread:
#2 close_unit_1 ../../../repos/gcc/libgfortran/io/unit.c:734 LOCK
(&unit_lock)
Mutex M25 previously acquired by the same thread here:
#2 get_gfc_unit ../../../repos/gcc/libgfortran/io/unit.c:380 TRYLOCK
(&p->lock)
* * *
(B) -fsanitize=address / -fsanitize=leak
* Direct leak of 80 byte(s) in 1 object(s) allocated from:
#1 0x7ff684a15c54 in _gfortrani_enqueue_done_id
../../../repos/gcc/libgfortran/io/async.c:289
which is:
enqueue_done_id (async_unit *au, enum aio_do type)
...
transfer_queue *tq = calloc (sizeof (transfer_queue), 1);
...
au->tail->next = tq;
and should get freed in
async_io (void *arg)
which looks okay.
* And I see a bunch of:
#1 0x7f3da3491bb8 in _gfortrani_xmalloc
../../../repos/gcc/libgfortran/runtime/memory.c:38
(xmalloc is used throughout libgfortran/io/*.c)
(C) On the other hand, valgrind shows:
All heap blocks were freed -- no leaks are possible
thus (B) might be a false positive.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100352
[Bug 100352] [11/12 Regression] libgomp.fortran/async_io_1.f90 -O0 execution
test
