[mpich-discuss] valgrind warning with ROMIO hint file

[Eric Chamberland]

Hi,

we have the same issue here...

Reported this 3 days ago:

https://github.com/pmodels/mpich/issues/2894

Eric

On 19/12/17 07:30 PM, Audet, Martin wrote:
> MPI_Developers,
> It seems that when a program using mpich uses MPI-IO, it try first to open
> a hint file specified in the ROMIO_HINTS environment variable (or
> "/etc/romio-hints" if it is undefined) and then try to read it. The problem
> is that it will try to read from it with the file descriptor returned by
> open() even if the open() failed and returned a -1 (ex: file not found).
> When this happens read() also fails and also return -1.
> The problem is when the program is run under valgrind (with the valgrind
> friendly ch3:sock device), valgrind notice that an invalid file descriptor
> was passed to read() and complain with a warning:
> ==113473== Memcheck, a memory error detector
> ==113473== Copyright (C) 2002-2015, and GNU GPL'd, by Julian Seward et al.
> ==113473== Using Valgrind-3.12.0 and LibVEX; rerun with -h for copyright 
> info
> ==113473== Command: ...
> ==113473== Parent PID: 48694
> ==113473==
> ==113473== Warning: invalid file descriptor -1 in syscall read()
> ==113473==
> ==113473== HEAP SUMMARY:
> ==113473==     in use at exit: 0 bytes in 0 blocks
> ==113473==   total heap usage: 4,420 allocs, 4,209 frees, 72,241,561 
> bytes allocated
> ==113473==
> ==113473== All heap blocks were freed -- no leaks are possible
> ==113473==
> ==113473== For counts of detected and suppressed errors, rerun with: -v
> ==113473== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)
> The problem is that no matter how clean is the program, this warning will
> appear in its valgrind report. A developer may think that his own code is
> problematic and start investigating...
> The solution is of course not trying to read the file if the file descriptor
> is invalid. This could be done simply as follow (mpich 3.2.1):
> --- mpich-3.2.1/src/mpi/romio/adio/common/system_hints.c
> +++ mpich-3.2.1-patch/src/mpi/romio/adio/common/system_hints.c
> @@ -98,7 +98,7 @@
>       buffer = (char *)ADIOI_Calloc(HINTFILE_MAX_SIZE, sizeof (char));
>       if (rank == 0) {
> -       ret = read(fd, buffer, HINTFILE_MAX_SIZE);
> +       ret = (fd >= 0) ? read(fd, buffer, HINTFILE_MAX_SIZE) : -1;
>          /* any error: bad/nonexistent fd, no perms, anything: set up a null
>           * buffer and the subsequent string parsing will quit 
> immediately */
>          if (ret == -1)
> Could you consider applying this patch (or an equivalent one)
> to mpich ?  It would be much appreciated.
> Thanks in advance,
> Martin Audet
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