From owner-freebsd-stable@freebsd.org  Sat Jul 22 07:05:35 2017
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Date: Sat, 22 Jul 2017 10:05:29 +0300
From: Konstantin Belousov <kostikbel@gmail.com>
To: Eugene Grosbein <eugen@grosbein.net>
Cc: Don Lewis <truckman@FreeBSD.org>, pz-freebsd-stable@ziemba.us,
 freebsd-stable@FreeBSD.org
Subject: Re: stable/11 r321349 crashing immediately
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On Sat, Jul 22, 2017 at 12:51:01PM +0700, Eugene Grosbein wrote:
> Also, there is https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219476

I strongly disagree with the idea of increasing the default kernel
stack size, it will cause systematic problems for all users instead of
current state where some workloads are problematic.  Finding contig
KVA ranges for larger stacks on KVA-starved architectures is not going
to work.

The real solution is to move allocations from stack to heap, one by one.

You claimed that vm/vm_object.o consumes 1.5K of stack, can you show
the ddb backtrace of this situation ?