NetBSD Problem Report #55299
From www@netbsd.org Mon May 25 04:40:00 2020
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for <gnats-bugs@gnats.NetBSD.org>; Mon, 25 May 2020 04:39:59 +0000 (UTC)
Message-Id: <20200525043958.C82921A9245@mollari.NetBSD.org>
Date: Mon, 25 May 2020 04:39:58 +0000 (UTC)
From: roland.illig@gmx.de
Reply-To: roland.illig@gmx.de
To: gnats-bugs@NetBSD.org
Subject: DTrace runs into triple fault
X-Send-Pr-Version: www-1.0
>Number: 55299
>Category: kern
>Synopsis: DTrace runs into triple fault
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: kern-bug-people
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Mon May 25 04:40:00 +0000 2020
>Originator: Roland Illig
>Release: 8.0
>Organization:
>Environment:
NetBSD nb8.roland-illig.de 8.0 NetBSD 8.0 (GENERIC.PROF) #0: Sun May 17 14:12:24 UTC 2020 rillig@nb8.roland-illig.de:/home/rillig/proj/src8/sys/arch/amd64/compile/GENERIC.PROF amd64
>Description:
When I wanted to know why some read(2) and write(2) calls were unreasonably slow inside a VirtualBox VM, I was suggested to try DTrace to trace down the root cause.
I tried that, and got a triple fault.
(See https://gnats.netbsd.org/55271 for another try to get to the root cause.)
cat > read-triple-fault.d <<EOF
#pragma D option flowindent
syscall::read:entry
/execname == "wc" && guard++ == 0/
{
self->traceme = 1;
}
fbt:::
/self->traceme/
{
printf("%d\n", walltimestamp);
}
syscall::read:return
/self->traceme/
{
self->traceme = 0;
}
EOF
dtrace -s read-triple-fault.d
wc -l /netbsd
>How-To-Repeat:
>Fix:
(Contact us)
$NetBSD: query-full-pr,v 1.46 2020/01/03 16:35:01 leot Exp $
$NetBSD: gnats_config.sh,v 1.9 2014/08/02 14:16:04 spz Exp $
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