[Bug fortran/95546] New: Random Fortran test failures

[Bug fortran/95546] New: Random Fortran test failures

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

            Bug ID: 95546
           Summary: Random Fortran test failures
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com
                CC: skpgkp2 at gmail dot com
  Target Milestone: ---

I got random failures:

t line 12 of file
/export/gnu/import/git/gcc-test-master-intel64/src-master/gcc/testsuite/gfortran.dg/eof_4.f90
(unit = 99)
Fortran runtime error: Cannot open file 'test.dat': File exists 

Error termination. Backtrace:
#0  0x7f6dc5baf37c in already_open
        at ../../../src-master/libgfortran/io/open.c:720
#1  0x4012bb in ??? 
#2  0x4034df in ??? 
#3  0x7f6dc55e2071 in ??? 
#4  0x40115d in ??? 
#5  0xffffffffffffffff in ??? 
FAIL: gfortran.dg/eof_4.f90   -O0  execution test

There are

gfortran.dg/direct_io_12.f90:open(99, file='test.dat', form='unformatted',
access='direct', recl=size*8)
gfortran.dg/endfile.f90:     
open(unit=10,file='test.dat',access='sequential',status='replace')
gfortran.dg/endfile.f90:     
open(unit=10,file='test.dat',access='sequential',status='old')
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/eof_4.f90:open(99, file="test.dat", access="stream",
form="unformatted", status="new")
gfortran.dg/eof_4.f90:open(99, file="test.dat")
gfortran.dg/implied_do_io_1.f90:  open(10,file="test.dat")
gfortran.dg/list_read_7.f90:open(unit=20, file='test.dat',form='FORMATTED',
status="replace")
gfortran.dg/namelist_76.f90: 
open(unit=10,form='formatted',status='replace',action='write',file='test.dat')
gfortran.dg/namelist_97.f90:  open  (unit=10, file='test.dat', form=my_form)
gfortran.dg/open_new_segv.f90:  ! Make sure pr64770test.dat exists
gfortran.dg/open_new_segv.f90:  open(99, file="pr64770test.dat",
status="replace")
gfortran.dg/open_new_segv.f90:  open(99, file="pr64770test.dat",
access="stream", form="unformatted", &
gfortran.dg/open_new_segv.f90:! { dg-output "Fortran runtime error: Cannot open
file .pr64770test.dat.:" }
gfortran.dg/open_new_segv.f90:! { dg-final { remote_file build delete
"pr64770test.dat" } }
gfortran.dg/read_eof_8.f90:  open(unit=25,file="test.dat",status="replace", &

[Bug fortran/95546] Random Fortran test failures

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-06-04
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
It happens with "make -jN check".

[Bug fortran/95546] Random Fortran test failures

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kargl at gcc dot gnu.org

--- Comment #2 from kargl at gcc dot gnu.org ---
(In reply to H.J. Lu from comment #1)
> It happens with "make -jN check".

The Fortran code is correct.

If 'make -jN check' is trying to build and execute multiple
versions of eof_4.f90 in parallel, then that won't work.  
Looks like you have a race condition with parallel make.

[Bug fortran/95546] Random Fortran test failures

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

--- Comment #3 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
I have seen that too with -j8.

AFAICT the problem is that the test expects there is no file 'test.dat'.

[Bug testsuite/95546] Random Fortran test failures

[jvdelisle at charter dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

jvdelisle at charter dot net changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jvdelisle at charter dot net

--- Comment #4 from jvdelisle at charter dot net ---
I am curious, did this just start happening or is it a long time issue just
reported.  Locking mecahnisms were adjusted recently I believe.

[Bug testsuite/95546] Random Fortran test failures

[sgk at troutmask dot apl.washington.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

--- Comment #5 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Fri, Jun 05, 2020 at 03:46:18PM +0000, jvdelisle at charter dot net wrote:
> 
> I am curious, did this just start happening or is it a long time issue just
> reported.  Locking mecahnisms were adjusted recently I believe.
> 

What locking are you referring to?  If it some recent changes
to libgfortran's pthread locking, then I think that has nothing
to do with the problem reported here.

The code eof_4.f90 runs multiple tests.  The looks like

  open(unit=99, file='test.dat', status='new')
  !
  ! Test 1
  !
  close(99, status='delete')

  open(unit=99, file='test.dat', status='new')
  !
  ! Test 2
  !
  close(99, status='delete')

  open(unit=99, file='test.dat', status='new')
  !
  ! Test 3
  !
  close(99, status='delete')

The above is actually testing Fortran feature.

HJ Lu reported problems with 'make -jN', which suggests that
eof_4.f90 is being compiled and executed in parallel.  That
is subject to races.  Dejagnu needs to be told that eof_4.f90
cannot be run in parallel.  If it is not possible to defeat
dejagnu, then the test will need to changed to use a unique
file name

  character(len=20) name  
  write(name, '(A,I0,A)') 'tmp', getpid(), '.dat'

  open(unit=99, file=name, status='new')
  !
  ! Test 1
  !
  close(99, status='delete')

The test could also be adjusted to use inquire() and sleep()
(need to check syntax)

1 inquire(file='test.dat', exists=stat)
  if (stat == 1) then
     call sleep(2)
     goto 1
  end if

[Bug testsuite/95546] Random Fortran test failures

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95546

--- Comment #6 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
> I am curious, did this just start happening or is it a long time issue just reported.

The test is quite old: Feb 18  2018. I did not see any failure for it until now
(one instance).