From owner-freebsd-current@freebsd.org  Wed Aug 22 18:39:45 2018
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Date: Wed, 22 Aug 2018 21:32:47 +0300
From: Greg V <greg@unrelenting.technology>
Subject: Re: dmesg output I don't understand
To: Per Gunnarsson <p.gunnarsson@yahoo.com>
Cc: freebsd-current@freebsd.org
Message-Id: <1534962767.74383.2@hraggstad.unrelenting.technology>
In-Reply-To: <fdc351a7-b19f-3d19-60ad-9045ab26b132@yahoo.com>
References: <fdc351a7-b19f-3d19-60ad-9045ab26b132@yahoo.com>
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On Wed, Aug 22, 2018 at 7:20 PM, Per Gunnarsson 
<p.gunnarsson@yahoo.com> wrote:
> Hello!
> 
> What do these lines in my dmesg mean?
> 
> I am on amd64.
> 
> /usr/src Revision: 338177
> 
> /usr/ports Revision: 477773
> 
> P.S
> 
> I got Fatal trap 12 with this revision after installing several fusefs
> modules from ports.
> 
> After removing fuse from my loader.conf, things booted again.
> 
> Regards,
> 
> Per Gunnarsson
> 
> lock order reversal:
>  1st 0xfffffe0000e82d80 bufwait (bufwait) @ 
> /usr/src/sys/kern/vfs_bio.c:3916
>  2nd 0xfffff80005787000 dirhash (dirhash) @
> /usr/src/sys/ufs/ufs/ufs_dirhash.c:289

Hi,

this is debugging output you're seeing because your kernel is built 
with the WITNESS option.
(e.g. the default GENERIC kernel in -CURRENT)

lock order reversal is a very common message, you can ignore it.

Switch to GENERIC-NODEBUG to get rid of the messages and get a 
performance boost (these safety checks impact syscall performance)