linux-kernel - Re: [PATCH] acpi/ghes: add TAINT_MACHINE

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Message-ID: <aGVyX0jqwTPkCVqY@agluck-desk3>
Date: Wed, 2 Jul 2025 10:54:39 -0700
From: "Luck, Tony" <tony.luck@...el.com>
To: Breno Leitao <leitao@...ian.org>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
	James Morse <james.morse@....com>, Borislav Petkov <bp@...en8.de>,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	kernel-team@...a.com, kbusch@...nel.org, rmikey@...a.com
Subject: Re: [PATCH] acpi/ghes: add TAINT_MACHINE_CHECK on GHES panic path

On Wed, Jul 02, 2025 at 10:22:50AM -0700, Breno Leitao wrote:
> On Wed, Jul 02, 2025 at 09:31:30AM -0700, Luck, Tony wrote:
> > On Wed, Jul 02, 2025 at 08:39:51AM -0700, Breno Leitao wrote:
> > So unless someone feels it would be better to create a new TAINT
> > flag (TAINT_FATAL_GHES? TAINT_FIRMWARE_REPORTED_FATAL_ERRROR?)
> > then this seems OK to me.
> 
> Thanks. That brings another topic. I am seeing crashes and warnings that
> are only happening after recoverable errors. I.e, there is a GHES
> recoverable error, and then machine crashes minutes later. A classical
> example is when the PCI downstream port disappear, and recovers later,
> re-enumerating everything, which is simply chaotic.
> 
> I would like to be able to correlate the crash/warning with a machine
> that had a recoverable error. At scale, this improves the kernel
> monitoring by a lot.
> 
> So, if we go toward using TAINT_FATAL_GHES, can we have two flavors?
> TAINT_FATAL_GHES_RECOVERABLE and TAINT_FATAL_GHES_FATAL?

Do you really want to TAINT for recoverable errors? If most errors
are successfully recovered, then a TAINT indication that a recovery
happened a week ago would be misleading.

Maybe better to save a timestamp for when the most recent recoverable
error occurred, then compare that against the current time in panic()
path and print warning if the recoverable error was "recent" (for
some TBD value of "recent").

-Tony