Re: random crashes on -HEAD for a few days now

Stefan Kaltenbrunner <stefan@kaltenbrunner.cc> writes:
> at least one of my buildfarm members (emu) is crashing on what seems 
> totally unrelated regression tests for a few days now:

I was wondering about that ...

> it took me about 10 tries to reproduce that manually and I'm getting the 
> following stacktrace:

> #0  varbit_out (fcinfo=0x88c75000) at varbit.c:549
> 549             x = *sp;

Just eyeballing that code, it looks like it will try to fetch the byte
immediately beyond the end of the bit array, when the number of bits is
an exact multiple of 8.  This is unlikely to cause a problem but it
*could* happen that the input is right up against the end of memory.
Could you check whether that is what happened here?  (The important
question is whether the input seems to be sane, ie, "len" isn't huge.)
        regards, tom lane