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

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Date: Thu, 21 Dec 2023 15:12:46 -0800
From: Randy Dunlap <rdunlap@...radead.org>
To: Greg KH <gregkh@...uxfoundation.org>,
 Sreenath Vijayan <sreenath.vijayan@...y.com>
Cc: linux-doc@...r.kernel.org, linux-serial@...r.kernel.org, corbet@....net,
 jirislaby@...nel.org, linux-kernel@...r.kernel.org,
 anandakumar.balasubramaniam@...y.com,
 Shimoyashiki Taichi <taichi.shimoyashiki@...y.com>
Subject: Re: [PATCH] tty/sysrq: Dump kernel ring buffer messages via sysrq



On 12/21/23 08:52, Greg KH wrote:
> On Thu, Dec 21, 2023 at 07:09:53PM +0530, Sreenath Vijayan wrote:
>> When terminal is unresponsive, one cannot use dmesg to view kernel
>> ring buffer messages. Also, syslog services may be disabled,
>> to check them after a reboot, especially on embedded systems.
>> In this scenario, dump the kernel ring buffer messages via sysrq
>> by pressing sysrq+D.
>>
>> Signed-off-by: Sreenath Vijayan <sreenath.vijayan@...y.com>
>> Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@...y.com>
>> ---
>>  Documentation/admin-guide/sysrq.rst |  2 ++
>>  drivers/tty/sysrq.c                 | 43 ++++++++++++++++++++++++++++-
>>  2 files changed, 44 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/admin-guide/sysrq.rst b/Documentation/admin-guide/sysrq.rst
>> index 2f2e5bd440f9..464c4e138b9d 100644
>> --- a/Documentation/admin-guide/sysrq.rst
>> +++ b/Documentation/admin-guide/sysrq.rst
>> @@ -161,6 +161,8 @@ Command	    Function
>>              will be printed to your console. (``0``, for example would make
>>              it so that only emergency messages like PANICs or OOPSes would
>>              make it to your console.)
>> +
>> +``D``	    Dump the kernel ring buffer
>>  =========== ===================================================================
> 
> Nit, this doesn't line up anymore :(

Yes, that will cause a docs build warning.

Also, can you be more explicit about which ring buffer this patch
is referring to, please.


-- 
#Randy
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