From: "John B. Wyatt IV" <jwyatt@redhat.com>
To: Petr Mladek <pmladek@suse.com>
Cc: John Ogness <john.ogness@linutronix.de>,
Clark Williams <williams@redhat.com>,
jlelli@redhat.com, Derek Barbosa <debarbos@redhat.com>,
"John B. Wyatt IV" <sageofredondo@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>
Subject: Re: NMI Reported with console_blast.sh
Date: Fri, 1 Mar 2024 11:53:18 -0500 [thread overview]
Message-ID: <ZeIH_l4T2uIanMyZ@thinkpad2021> (raw)
In-Reply-To: <ZeBnUCk598gttpds@alley>
On Thu, Feb 29, 2024 at 12:15:28PM +0100, Petr Mladek wrote:
> On Thu 2024-02-22 00:21:19, John B. Wyatt IV wrote:
> > On Mon, Feb 12, 2024 at 04:23:04PM -0500, John B. Wyatt IV wrote:
> >
> > I found 2 additional NMIs for a total of 3. Number 2 is very
> > large-please feel free to let me know what specific information you
> > wanted if it was unnecessary.
> >
> > This first one (the original) is with the real-time profile (no preemption).
> > The next two are with the performance-througput (no preemption).
> >
> > This is what real-time NMI reports with the caller information enabled. It
> > looks like it is lacking some information compared to the other two further below.
> >
> > [ T2481] Call Trace:
> > [ T2477] Kernel panic - not syncing: sysrq triggered crash
> > [ C0] NMI backtrace for cpu 0
>
> This message seems to be printed by nmi_cpu_backtrace().
>
> I am surprised. I would expect to see the backtrace printed from panic().
> It calls dump_stack() directly on the panic-CPU. And this panic() should
> be called from sysrq_handle_crash(). IMHO, it should be (normal)
> interrupt context.
>
> Is it different on RT?
Yes. There are no NMIs on this machine in my tests for when I run an RT
enabled kernel.
>
> Or have you somehow modified the kernel to use NMI for sysrq?
>
I have not modified the kernel source code from 6.7.0-rt6.
--
Sincerly,
John Wyatt
Software Engineer, Core Kernel
next prev parent reply other threads:[~2024-03-01 16:53 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-08 0:43 NMI Reported with console_blast.sh John B. Wyatt IV
2024-02-09 9:11 ` John Ogness
2024-02-09 20:50 ` John B. Wyatt IV
2024-02-10 21:27 ` John Ogness
2024-02-12 21:23 ` John B. Wyatt IV
2024-02-22 5:21 ` John B. Wyatt IV
2024-02-29 11:15 ` Petr Mladek
2024-02-29 11:19 ` Petr Mladek
2024-03-01 10:11 ` Sebastian Andrzej Siewior
2024-03-01 16:53 ` John B. Wyatt IV [this message]
2024-02-20 22:24 ` John B. Wyatt IV
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