[mvapich-discuss] Segfault in MPI_Reduce

[Khuvis, Samuel]

Hi,

I get a segfault when running a code with MV2 2.3 but not with MV2 2.2. It segfaults in the memcpy call in MPIR_Localcopy, which is called from MPI_Reduce. This only seems to happen when memory is allocated for the recv_buf on the root process and not on all processes.

I have attached a small reproducer to this email. This seems to happen in all cases with the full code, but for the attached code I need to compile with “mpicc -g -check-pointers=rw” to reproduce the error. The attached code should segfault with 2.3 but not 2.2. Also, if you comment out line 15 it should run without segfault-ing with both versions.

--
Samuel Khuvis
Scientific Applications Engineer
Ohio Supercomputer Center (OSC)<https://osc.edu/>
A member of the Ohio Technology Consortium<https://oh-tech.org/>
1224 Kinnear Road, Columbus, Ohio 43212
Office: (614) 292-5178<tel:+16142925178> • Fax: (614) 292-7168<tel:+16142927168>

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