Comment 6 for bug 1124503

Hi,
We managed to (sort of) reproduce this error when upgrading from 5.1.59 to 5.1.68.
Interestingly enough, it always seem to happen with the same table, where we'll get the "hash index ref_count is not zero" warnings, and things will just freeze if we try to drop that table.

So far we've only been able to reproduce it in production, I've been trying to create a minimal test case without much luck so far.
I'm attaching stack trace generated after trying to drop the table in case it's helpful.

(Also note that downgrading from 5.1.68 to 5.1.63 seemed to fix things for us)