Concurrent HDF5 access crashes wsgi server (even with --enable-threadsafe)

Yoshua_Wakeham · July 13, 2016, 4:34am

Hi there,

I'm using HDF5 files as a data storage format for a low-traffic web application, which is built in Pyramid (Python framework) and running on the Waitress WSGI server. We have encountered a nasty bug where if multiple requests (threads) concurrently read different HDF5 files, the server crashes with a segmentation fault. The crash is definitely thread-related, because the bug vanishes if we restrict the server to be single-threaded.

Note that the crash does not occur when multiple threads read the *same* HDF5 file. Only when multiple HDF5 files are being accessed simultaneously.

We have built libhdf5 (version 1.8.16) with --enable-threadsafe turned on; the ttsafe tests run successfully.

Any help in resolving the bug would be much appreciated.

Best regards,
Yoshua Wakeham

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epourmal · July 15, 2016, 4:17am

Yoshua,

Would it be possible for you to reproduce the issue using C application and submit it to help@hdfgorup.org<mailto:help@hdfgorup.org>?

Thank you!

Elena

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On Jul 12, 2016, at 11:34 PM, Yoshua Wakeham <wakeham.y@wehi.EDU.AU<mailto:wakeham.y@wehi.edu.au>> wrote: