Re: hashtable crash (was Re: [PATCHES] Post-mortem: final 2PC patch)

Tom Lane wrote:

> dynahash.c thinks it should always copy 255 bytes of key, since that's
> what it was told the key size was ... but in this case the supplied
> search key has been allocated very close to the end of the process's
> memory, and there are not 255 bytes before the end of memory.

aaah - this description rings a bell ...

OpenBSD has some very useful features for configuration of malloc() -
and on this particular box it has:

G       ``Guard''.  Enable guard pages and chunk randomization.  Each            page size or larger allocation is
followedby a guard page that            will cause a segmentation fault upon any access.  Smaller than            page
sizechunks are returned in a random order.
 


and indeed - enabling "G" on another (x86) OpenBSD box of mine causes
make check to die there too ....


Stefan