NetBSD Problem Report #57102
From www@netbsd.org Sat Dec 10 16:03:23 2022
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for <gnats-bugs@gnats.NetBSD.org>; Sat, 10 Dec 2022 16:03:22 +0000 (UTC)
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Date: Sat, 10 Dec 2022 16:03:20 +0000 (UTC)
From: cryintothebluesky@gmail.com
Reply-To: cryintothebluesky@gmail.com
To: gnats-bugs@NetBSD.org
Subject: vcmbox0 thread using 100% CPU
X-Send-Pr-Version: www-1.0
>Number: 57102
>Category: port-arm
>Synopsis: vcmbox0 thread using 100% CPU
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: port-arm-maintainer
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Sat Dec 10 16:05:00 +0000 2022
>Last-Modified: Sat Dec 10 19:00:03 +0000 2022
>Originator: Sad Clouds
>Release: 9.99.108
>Organization:
>Environment:
NetBSD rp4 9.99.108 NetBSD 9.99.108 (GENERIC64) #0: Fri Dec 9 13:52:51 GMT 2022
>Description:
The issue occurred on Raspberry Pi 4, used as NFS server. Initiated a large copy from Linux NFS client to NetBSD NFS server. Some time later, vcmbox0 thread was consuming 100% CPU and the following message was logged before I rebooted the system
Dec 10 15:01:13 rp4 /netbsd: [ 721.2070326] vcmbox0: workqueue busy: updates stopped
Running envstat on command line blocked indefinitely.
Reboot was the only way to resolve the issue. Looks like there may be a bug that results in infinite loop.
>How-To-Repeat:
Not sure, after reboot, subsequent NFS usage did not reproduce the issue.
>Fix:
>Audit-Trail:
From: Taylor R Campbell <riastradh@NetBSD.org>
To: cryintothebluesky@gmail.com
Cc: gnats-bugs@netbsd.org, port-arm-maintainer@netbsd.org,
gnats-admin@netbsd.org, netbsd-bugs@netbsd.org
Subject: Re: port-arm/57102: vcmbox0 thread using 100% CPU
Date: Sat, 10 Dec 2022 18:58:37 +0000
> Date: Sat, 10 Dec 2022 16:05:00 +0000 (UTC)
> From: cryintothebluesky@gmail.com
>
> The issue occurred on Raspberry Pi 4, used as NFS server. Initiated
> a large copy from Linux NFS client to NetBSD NFS server. Some time
> later, vcmbox0 thread was consuming 100% CPU and the following
> message was logged before I rebooted the system
If you catch this again, it would be helpful if you could start
crash(8), run
crash> ps
to find the thread occupying the CPU, which will look something like
this:
10618>10618 7 1 0 ffffa06b1676e940 sh
Note the `>' on the line marking it as a running thread, and the
thread name is not `idle/N'. Most likely the thread name will be
vcmbox0 or something. Copy & paste the horrible number like
ffffa06b1676e940 into bt/a:
crash> bt/a ffffa06b1676e940
Sharing the stack trace should help track down what it's up to.
The full output of ps and ps/w might also be helpful, so it wouldn't
hurt to include those too.
(Contact us)
$NetBSD: query-full-pr,v 1.47 2022/09/11 19:34:41 kim Exp $
$NetBSD: gnats_config.sh,v 1.9 2014/08/02 14:16:04 spz Exp $
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