Re: Segfault on "task <Tab><Tab>" with zsh 5.0.2 (minimal dataset to reproduce the issue found)

[Bart Schaefer <schaefer@xxxxxxxxxxxxxxxx>]

On Sep 17,  8:05pm, Peter Stephenson wrote:
}
} Well, completion's very slow, suggesting something fairly heavy is
} happening, but it hasn't crashed yet.  I don't suppose it's memory
} exhaustion?  The shell's not very robust about that.

The stack trace from the very first message in the thread indicates
it dies dereferencing the descr field of a Cvdef structure from the
cvdef_cache array.  The trace doesn't show the call to zsfree so it
is the Cvdef pointer itself that is bad, not the struct contents.

The valgrind output confirms this, which seems to indicate that the
cvdef_cache array is being scribbled on ... but that's static memory,
so it would have to be from overflowing some adjacent static storage
(?) and 0x100000001 looks suspicious as a value that's repeatably so
scribbled.

A watchpoint on cvdef_cache[0] might shed some light.