On 05/07/2015 06:58 AM, Lisandro Dalcin wrote:

This is using the preview release 3.2b2, I discovered this issue months ago and it seems I forgot to report it.

Thanks for reporting these two issues. These two patches (attached) address your test case, but it's a part of the code I don't play in often, so I'm going to need a review on them before committing: ==rob

1) MPI_File_call_errhandler(file, value) should return MPI_SUCCESS instead of value under normal operation (as the MPI spec says), and particularly if the error handler is set to MPI_ERRORS_RETURN. This bug is trivial to fix.

2) Setting the predefined error handler MPI_ERRORS_ARE_FATAL and calling MPI_File_call_errhandler(file, errcode) should "gracefully" abort the processes the MPI way, instead of segfaulting. The problem here is that ROMIO has to somehow handle MPI_ERRORS_ARE_FATAL in some special way I'm not sure how to implement, right now it is trying to invoke a callback that is set to NULL.

I'm attaching a test case showcasing the two issues, and pasting output below:

$ cat file_errhdl.c #include <mpi.h> #include <stdio.h>

int main(int argc, char *argv[]) { int ierr; MPI_File fh; MPI_Init(&argc, &argv);

MPI_File_open(MPI_COMM_WORLD,"/tmp/datafile", MPI_MODE_CREATE|MPI_MODE_RDWR|MPI_MODE_DELETE_ON_CLOSE, MPI_INFO_NULL,&fh);

MPI_File_set_errhandler(fh,MPI_ERRORS_RETURN); ierr = MPI_File_call_errhandler(fh,MPI_ERR_FILE); printf("ierr: %d, expected: %d\n", ierr, (int)MPI_SUCCESS);

MPI_File_set_errhandler(fh,MPI_ERRORS_ARE_FATAL); MPI_File_call_errhandler(fh,MPI_ERR_FILE); /* should abort */ MPI_File_close(&fh);

MPI_Finalize(); return 0; }

$ mpicc file_errhdl.c

$ ./a.out ierr: 27, expected: 0 Segmentation fault (core dumped)

$ valgrind -q ./a.out ierr: 27, expected: 0 ==30036== Jump to the invalid address stated on the next line ==30036== at 0x0: ??? ==30036== by 0x4CE8EDC: PMPI_File_call_errhandler (file_call_errhandler.c:105) ==30036== by 0x400951: main (in /home/dalcinl/Devel/BUGS-MPI/mpich/a.out) ==30036== Address 0x0 is not stack'd, malloc'd or (recently) free'd ==30036== ==30036== ==30036== Process terminating with default action of signal 11 (SIGSEGV) ==30036== Bad permissions for mapped region at address 0x0 ==30036== at 0x0: ??? ==30036== by 0x4CE8EDC: PMPI_File_call_errhandler (file_call_errhandler.c:105) ==30036== by 0x400951: main (in /home/dalcinl/Devel/BUGS-MPI/mpich/a.out) Segmentation fault (core dumped)

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-- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA