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Date: Sun, 5 Apr 2015 20:37:23 +0300
From: Konstantin Belousov <kostikbel@gmail.com>
To: Gleb Smirnoff <glebius@FreeBSD.org>
Subject: Re: panic: Lock vm object not exclusively locked @
 /usr/src/sys/vm/vm_page.c:2637
Message-ID: <20150405173723.GR2379@kib.kiev.ua>
References: <20150405133758.GA40261@albert.catwhisker.org>
 <20150405154721.GO64665@FreeBSD.org>
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On Sun, Apr 05, 2015 at 06:47:21PM +0300, Gleb Smirnoff wrote:
> This is r281079.
> 
> Since vm_page_advise() may call vm_page_dirty() in the MADV_DONTNEED case,
> the assertion is valid. So, looks like vm_fault_dontneed() needs W-lock on
> the first_object.
> 
Either this, or vm_page_advise() could be changed to do nothing in the
case of MADV_DONTNEED operation and a need to call vm_page_dirty(), if
the object is only read-locked.