From mboxrd@z Thu Jan  1 00:00:00 1970
From: erik quanstrom <quanstro@coraid.com>
Date: Fri, 31 Jul 2009 15:40:41 -0400
To: 9fans@9fans.net
Message-ID: <3aa6d689be5c81fc7ac72211cfee8b13@coraid.com>
In-Reply-To: <8ab5e568a932c69389783454382c2401@terzarima.net>
References: <8ab5e568a932c69389783454382c2401@terzarima.net>
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Subject: Re: [9fans] Race condition in /sys/src/9/pc/trap.c?
Topicbox-Message-UUID: 33f4dd3a-ead5-11e9-9d60-3106f5b1d025

> it ensures mmuflushes in all other processes (sharing that segment) as well.
> in fact, the crash you describe just emphasises that point:
> the page reference no longer exists, hence the fault.
>
> the problem (which frankly doesn't bother me) is that fault386
> is being overly cautious in assuming that a page fault that occurs
> in system mode but can't map a page successfully is necessarily a kernel bug:
> that's not true. it could just note the process instead.
> (it doesn't bother me because since unix days i've seen less than a handful
> of programs that SHRINK their existing data segments, and i think that's the
> only case that can cause the panic you're seeing.)

if this case is really not important, would it make sense
to disallow shrinking segments? it might be worth it just
to be able to define Eshrinkage.

- erik