From: Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>
To: Lukas Wunner <lukas@wunner.de>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: Stack trace when removing Thunderbolt devices while kernel shutting down
Date: Tue, 18 Feb 2020 16:57:29 +0000 [thread overview]
Message-ID: <PSXP216MB043813ED0773A4D7E842B3A680110@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20200218150124.stvsj2rozxrgxw2h@wunner.de>
On Tue, Feb 18, 2020 at 04:01:24PM +0100, Lukas Wunner wrote:
> On Tue, Feb 18, 2020 at 02:18:40PM +0000, Nicholas Johnson wrote:
> > If I surprise remove Thunderbolt 3 devices just as the kernel is
> > shutting down, I get stack dumps, when those devices would not normally
> > cause stack dumps if the kernel were not shutting down.
> >
> > Because the kernel is shutting down, it makes it difficult to capture
> > the logs without a serial console.
>
> Hold a camera in front of the screen and try to capture the messages
> as an MP4 movie which can be uploaded to YouTube or something.
https://www.youtube.com/watch?v=sDcYmbz7GME
The above is unlisted and will not appear in any search, so it will not
confuse my subscribers, but anybody with the link can view it (public).
I am still not sure I like the sound of my own voice. *cringe*
>
> If the output moves too fast to capture it, artificially slow it down
> by adding a udelay() to call_console_drivers() in kernel/printk/printk.c.
If you cannot get anything useful out of the aforementioned video, then
I will do this tomorrow evening. It is almost 1am now.
>
> Thanks,
>
> Lukas
By the way, this is not just with Linux v5.6-rcX. I have noticed this
for some time but it has been lower down my list in terms of priority
and urgency. I half expected it to be of no interest. I should have
mentioned it earlier, but before I might not have had as much time to
help investigate. I am currently looking for new kernel development
tasks because my previous ones are done.
Thanks,
Nicholas
prev parent reply other threads:[~2020-02-18 16:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-18 14:18 Stack trace when removing Thunderbolt devices while kernel shutting down Nicholas Johnson
2020-02-18 14:22 ` Bjorn Helgaas
2020-02-18 15:01 ` Lukas Wunner
2020-02-18 16:57 ` Nicholas Johnson [this message]
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