Re: any suggestions to detect memory corruption

Alex <zhihui.fan1213@gmail.com> writes:
> Someone add some code during backend init which used palloc. but at that
> time,  the CurrentMemoryContext is PostmasterContext.   at the end of
> backend initialization, the PostmasterContext is deleted, then the error
> happens.  the reason why it happens randomly is before the palloc, there
> are some other if clause which may skip the palloc.

> I still can't explain why PostmasterContext may have impact "index info"
> MemoryContext sometime,  but now I just can't reproduce it (before the
> fix,  it may happen in 30% cases).

Well, once the context is deleted, that memory is available for reuse.
Everything will seem fine until it *is* reused, and then boom!

The error would have been a lot more obvious if you'd enabled
MEMORY_CONTEXT_CHECKING, which would overwrite freed data with garbage.
That is normally turned on in --enable-cassert builds.  Anybody who's been
hacking Postgres for more than a week does backend code development in
--enable-cassert mode as a matter of course; it turns on a *lot* of
helpful cross-checks.

            regards, tom lane