NetBSD Problem Report #55550

From www@netbsd.org  Sat Aug  8 14:26:44 2020
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Date: Sat,  8 Aug 2020 14:26:43 +0000 (UTC)
From: rnestor@tx.rr.com
Reply-To: rnestor@tx.rr.com
To: gnats-bugs@NetBSD.org
Subject: System crash using gpt show
X-Send-Pr-Version: www-1.0

>Number:         55550
>Category:       kern
>Synopsis:       System crash using gpt show
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Aug 08 14:30:00 +0000 2020
>Last-Modified:  Sun Aug 09 05:20:01 +0000 2020
>Originator:     Bob Nestor
>Release:        9.99.69 Aug 7 10:00 UTC 2020
>Organization:
>Environment:
NetBSD 9.99.69 NetBSD 9.99.69 (GENERIC) #0: Thu Aug  6 10:00:21 UTC 2020  mkrepro@mkrepro.NetBSD.org:/usr/src/sys/arch/amd64/compile/GENERIC amd64

>Description:
Doing:

vndconfig -c vnd0 NetBSD-9.99.69-amd64.iso
gpt show vnd0

Causes system to crash
>How-To-Repeat:

>Fix:

>Audit-Trail:
From: Paul Goyette <paul@whooppee.com>
To: Robert Nestor <rnestor@mac.com>
Cc: gnats-bugs@netbsd.org
Subject: Re: kern/55550 - System crash using gpt show
Date: Sat, 8 Aug 2020 08:17:35 -0700 (PDT)

 >> 	vndconfig -c vnd0 NetBSD-9.99.69-amd64.iso
 >> 	gpt show vnd0
 >> 
 >> And the system immediately crashed.  Now maybe what I tried doing
 >> isn't permitted, but should the system crash just from trying to do
 >> it?
 >
 > No it should not crash.
 >
 > Please file a PR

 And could you copy-paste the crash backtrace to the PR audit trail,
 please?

 I thought this would be easy to reproduce by simply trying to run the
 ``gpt show'' command against any cd.  But within qemu it works just
 fine for me, for both a vnd0 and cd0 device.

 # gpt show /dev/cd0
 GPT not found, displaying data from MBR.

     start    size  index  contents
         0  106020         Unused
 # vnconfig -c vnd0 /boot-com.iso
 # gpt show vnd0
 GPT not found, displaying data from MBR.

     start    size  index  contents
         0  423936         Unused
 #


 +--------------------+--------------------------+-----------------------+
 | Paul Goyette       | PGP Key fingerprint:     | E-mail addresses:     |
 | (Retired)          | FA29 0E3B 35AF E8AE 6651 | paul@whooppee.com     |
 | Software Developer | 0786 F758 55DE 53BA 7731 | pgoyette@netbsd.org   |
 +--------------------+--------------------------+-----------------------+

From: Paul Goyette <paul@whooppee.com>
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: kern/55550 - System crash
Date: Sat, 8 Aug 2020 10:36:16 -0700 (PDT)

   This message is in MIME format.  The first part should be readable text,
   while the remaining parts are likely unreadable without MIME-aware tools.

 --0-1606171643-1596908176=:12972
 Content-Type: TEXT/PLAIN; charset=windows-1252; format=flowed
 Content-Transfer-Encoding: QUOTED-PRINTABLE

 Logging to PR audit trail...

 I didn't realize at the time that the iso file I was using for this was
 on an NFS share.  It crashes there, but if I move the file to a local
 disk then I don=92t see any crash and get the same output you got.  This
 is the BT for attempting this when the file is on an NFS share:

 cpu1: Begin traceback
 vpanic() at netbsd:vpanic+0x152
 snprintf() at netbsd:snprinf
 nfs_pathconf() at netbsd:nfs_pathconf
 VOP_STRATEGY() at netbsd:VOP_STRATEGY+0x64
 vndthread() at netbsd:vndthread+0x81e
 cpu1: End traceback


 --0-1606171643-1596908176=:12972--

From: Martin Husemann <martin@duskware.de>
To: gnats-bugs@netbsd.org
Cc: 
Subject: Re: kern/55550 - System crash using gpt show
Date: Sun, 9 Aug 2020 07:19:11 +0200

 Also from the off-ticket discussion, the NFS server seems to be relevant:

 > My NFS is on a DS218+ Synology NAS

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