Hello, I have used OpenMPI in conjunction with Valgrind for a long time now, and developed a list of suppressions for known false positives over time.
Now I am developing a library for inter-thread communication that is based on using OpenMPI with MPI_THREAD_MULTIPLE support. I have noticed that sending large messages from one thread to another in the same process will cause valgrind to complain about invalid reads. I have narrowed it down to one function being executed on four threads in one process. Attached is a tarball containing the error-reproducing program, valgrind suppression file, and valgrind output. The strange thing is that the valgrind error message doesn't fit the pattern of read-after-free or read-past-the-end. I'd like to know the following: 1) Should I even worry ? The code doesn't crash, only valgrind complains. Is it a harmless false positive ? 2) If it is an issue, am I using MPI right? 3) If I'm using it right, then what causes this ? some kind of internal buffering issue ? Note that I use Issend, so nothing should be freed until its completely been read (in theory). Thank you, -- Dan Ibanez
thread_test.tar
Description: Unix tar archive
