linux-kernel - Re: [PATCH] kernel/reboot: enhance dmesg logging for system restart

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Date: Sun, 23 Jun 2024 17:38:33 +0900
From: Dongmin Lee <ldmldm05@...il.com>
To: Faiyaz Mohammed <quic_faiyazm@...cinc.com>
Cc: benjamin.bara@...data.com, dmitry.osipenko@...labora.com, lee@...nel.org, 
	daniel.lezcano@...aro.org, j.granados@...sung.com, 
	linux-kernel@...r.kernel.org, dongmin.lee@...ux.dev
Subject: Re: [PATCH] kernel/reboot: enhance dmesg logging for system restart

On Wed, Jun 19, 2024 at 8:09 PM Faiyaz Mohammed
<quic_faiyazm@...cinc.com> wrote:
> Agreed in kernel view user's space reboot is intended but if system is
> silently rebooting due to any user process(vendor specific user process
> or even a OS specific user deamon) meeting any error condition then a
> developer debugging the system need to know which user process is
> issuing reboot system call to debug further, so in humble opinion it is
> helpful for system debug perspective.

Your situation is where system call tracing is required. Tracing
itself (via printing out kernel backtrace and/or comm and name) is
actually not what system calls should support regardless of debugging
level and/or kconfig option.

As I mentioned in earlier mail, you might use gdb debugger for the
purpose, or you might utilize SystemTap or eBPF to trace system calls
(including reboot call), actually these are for you to do system call
tracing rather than unnecessarily modifying system call's behavior.

You might want to refer to: https://lwn.net/Articles/852112/

Sincerely,
Dongmin Lee
https://ldmsys.net/