On 12/22/23 03:44, Sreenath Vijayan wrote: > On Thu, Dec 21, 2023 at 03:12:46PM -0800, Randy Dunlap wrote: >> >> >> 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@xxxxxxxx> >>>> Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@xxxxxxxx> >>>> --- >>>> 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. > > Thank you for the review comments. When I apply the patch, I don't > notice any alignment issues in the document. I tried with multiple > editors(vim,emacs) and the combination of tabs and spaces looks to > be the same as in the existing lines above the newly added line. > Tried "make htmldocs" and no warnings were observed and the html > page looks ok. Please suggest the modifications to be done. You are correct. Sorry for the confusion. It can be messy trying to read/review a diff when there is alignment involved. >> >> Also, can you be more explicit about which ring buffer this patch >> is referring to, please. >> > > We see the term "kernel ring buffer" used throughout the documents > and commit messages, and thought it is the right term. Even dmesg > manual page uses it. Would "kernel log buffer" be a more appropriate > term? Please share your suggestion. Documentation/admin-guide/kernel-parameters.txt refers to: ftrace ring buffer printk ring buffer tracing ring buffer so saying "kernel ring buffer" is not very specific. I expect that you are referring to the printk ring buffer, although I would prefer to call it something like the console log buffer (FWIW). thanks. -- #Randy https://people.kernel.org/tglx/notes-about-netiquette https://subspace.kernel.org/etiquette.html
