# Core dumps on write?

**URL:** <https://pyfr.discourse.group/t/core-dumps-on-write/153>\
**Category:** General\
**Created:** [5 May 2017 16:45 UTC](https://pyfr.discourse.group/t/core-dumps-on-write/153 "2017-05-05T16:45:47Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Robert\_Sawko1](https://avatars.discourse-cdn.com/v4/letter/r/9de053/32.png) [@Robert\_Sawko1](https://pyfr.discourse.group/u/Robert_Sawko1)\
**Post date:** [5 May 2017 16:45 UTC](https://pyfr.discourse.group/t/core-dumps-on-write/153/1 "2017-05-05T16:45:47Z")

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Hi,

PyFR started causing core dumps recently. I believe this is the moment the  
program begins to write to disk, but that may be misleading. I am attaching a  
log file. The same setup worked on exactly the same version before.

There were several updates on this machine like the CUDA driver for instance.  
Is there any specific python package I need to reinstall or update?

If you have any other thoughts, please let me know.  
Robert

[sd7003\_n1.out](https://pyfr.discourse.group/uploads/short-url/jocpWv1xtsVVjwzaN1QaVgamXmc.out) (32.3 KB)

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**Author:** ![fdw](https://avatars.discourse-cdn.com/v4/letter/f/a587f6/32.png) [@fdw](https://pyfr.discourse.group/u/fdw)\
**Post date:** [5 May 2017 18:36 UTC](https://pyfr.discourse.group/t/core-dumps-on-write/153/2 "2017-05-05T18:36:23Z")

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Hi Robert,

The crash is occurring in an MPI Waitall call. This is unlikely to be a  
PyFR issue. However, one thing you should try is recompiling mpi4py  
from scratch. This can be a bit of a pain (pip likes to cache stuff)  
but may solve any issues related to swapping of MPI libraries.

At first glance it does not appear to be disk related.

Regards, Freddie.

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<div class="post-metadata">

**Author:** ![Robert\_Sawko1](https://avatars.discourse-cdn.com/v4/letter/r/9de053/32.png) [@Robert\_Sawko1](https://pyfr.discourse.group/u/Robert_Sawko1)\
**Post date:** [8 May 2017 15:30 UTC](https://pyfr.discourse.group/t/core-dumps-on-write/153/3 "2017-05-08T15:30:37Z")

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Freddie,

Thanks for a quick reply. I retried with compilation of mpi4py but  
unfortunately it's the same. I can see a reference to Mellanox libraries too,  
so I am checking with admins if there were any recent updates there.

Robert