We have found one malloc(0) line in MPID_nem_init and fixed that. The change should be available in tomorrow’s nightly build tarball. http://www.mpich.org/static/downloads/nightly/master/mpich/ Thanks for reporting. — Huiwei Lu Postdoc Appointee Mathematics and Computer Science Division, Argonne National Laboratory http://www.mcs.anl.gov/~huiweilu/ On Mar 7, 2014, at 10:33 AM, Matthieu Dorier <[email protected]> wrote:

I didn't know electric-fence was so old. I managed to find the corruption with valgrind anyway, but it was just in case someone else wanted to use electric-fence.

Matthieu Dorier PhD student at ENS Rennes http://people.irisa.fr/Matthieu.Dorier ----- Mail original -----

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De: "Rob Latham" <[email protected]> À: [email protected] Envoyé: Vendredi 7 Mars 2014 16:35:27 Objet: Re: [mpich-discuss] Mpich failing electric-fence check

On 03/07/2014 09:25 AM, Jed Brown wrote:

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Matthieu Dorier <[email protected]> writes:

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ElectricFence Aborting: Allocating 0 bytes, probably a bug.

I would argue that ElectricFence is wrong here. The standard guarantees that malloc(0) succeeds and it is useful to simplify code and to test for matching free in cases where a positive size is rare.

It wouldn't suprise me to find ElecritcFence buggy. It was a great tool back in the day but Perens stopped maintaining it a decade ago, and there seem to be some half-hearted attempts by the community to keep it active (debian has some updates from... somewhere. http://duma.sourceforge.net/ might work?

I think everyone around here uses valgrind anyway.

==rob

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C99 §7.20.3: If the size of the space requested is zero, the behavior is implementation- defined: either a null pointer is returned, or the behavior is as if the size were some nonzero value, except that the returned pointer shall not be used to access an object.

Either way, the returned pointer can be passed to free. Are you aware of current malloc implementations which violate the above?

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-- Rob Latham Mathematics and Computer Science Division Argonne National Lab, IL USA _______________________________________________ discuss mailing list [email protected] To manage subscription options or unsubscribe: https://lists.mpich.org/mailman/listinfo/discuss

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