linux-kernel - Re: [PATCH v3 2/2] tty/sysrq: Dump printk ring buffer messages via sysrq

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Message-ID: <87il3rardk.fsf@jogness.linutronix.de>
Date: Thu, 18 Jan 2024 11:11:27 +0106
From: John Ogness <john.ogness@...utronix.de>
To: Sreenath Vijayan <sreenath.vijayan@...y.com>, corbet@....net,
 gregkh@...uxfoundation.org, jirislaby@...nel.org, rdunlap@...radead.org,
 pmladek@...e.com
Cc: rostedt@...dmis.org, senozhatsky@...omium.org,
 linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-serial@...r.kernel.org, taichi.shimoyashiki@...y.com,
 daniel.palmer@...y.com, anandakumar.balasubramaniam@...y.com,
 sreenath.vijayan@...y.com
Subject: Re: [PATCH v3 2/2] tty/sysrq: Dump printk ring buffer messages via
 sysrq

On 2024-01-17, Sreenath Vijayan <sreenath.vijayan@...y.com> wrote:
> When terminal is unresponsive, one cannot use dmesg to view printk
> ring buffer messages. Also, syslog services may be disabled,
> to check the messages after a reboot, especially on embedded systems.
> In this scenario, dump the printk ring buffer messages via sysrq
> by pressing sysrq+D.

Note that using sysrq+g with kgdb or kdb it is already possible to dump
the printk ringbuffer messages. However using this new sysrq+D is much
more comfortable, less intrusive, and generally safer.

I have no problems with this change. But I guess the tty maintainers
will need to speak up about extending the sysrq list.

John