linux-kernel - Re: [PATCH 20/30] panic: Add the panic informational notifier list

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Message-ID: <YoJbeuTNBXOIypSH@alley>
Date:   Mon, 16 May 2022 16:11:06 +0200
From:   Petr Mladek <pmladek@...e.com>
To:     "Guilherme G. Piccoli" <gpiccoli@...lia.com>
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Subject: Re: [PATCH 20/30] panic: Add the panic informational notifier list

On Wed 2022-04-27 19:49:14, Guilherme G. Piccoli wrote:
> The goal of this new panic notifier is to allow its users to
> register callbacks to run earlier in the panic path than they
> currently do. This aims at informational mechanisms, like dumping
> kernel offsets and showing device error data (in case it's simple
> registers reading, for example) as well as mechanisms to disable
> log flooding (like hung_task detector / RCU warnings) and the
> tracing dump_on_oops (when enabled).
> 
> Any (non-invasive) information that should be provided before
> kmsg_dump() as well as log flooding preventing code should fit
> here, as long it offers relatively low risk for kdump.
> 
> For now, the patch is almost a no-op, although it changes a bit
> the ordering in which some panic notifiers are executed - specially
> affected by this are the notifiers responsible for disabling the
> hung_task detector / RCU warnings, which now run first. In a
> subsequent patch, the panic path will be refactored, then the
> panic informational notifiers will effectively run earlier,
> before ksmg_dump() (and usually before kdump as well).
> 
> We also defer documenting it all properly in the subsequent
> refactor patch. Finally, while at it, we removed some useless
> header inclusions too.
> 
> Signed-off-by: Guilherme G. Piccoli <gpiccoli@...lia.com>

All notifiers moved in this patch seems to fit well the "info"
notifier list. The patch looks good from this POV.

I still have to review the rest of the patches to see if it
is complete.

Best Regards,
Petr