linux-kernel - [PATCH printk v2 0/2] Fix reported suspend failures

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Message-ID: <20251113160351.113031-1-john.ogness@linutronix.de>
Date: Thu, 13 Nov 2025 17:09:46 +0106
From: John Ogness <john.ogness@...utronix.de>
To: Petr Mladek <pmladek@...e.com>
Cc: Sergey Senozhatsky <senozhatsky@...omium.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Sherry Sun <sherry.sun@....com>,
	Jacky Bai <ping.bai@....com>,
	Jon Hunter <jonathanh@...dia.com>,
	Thierry Reding <thierry.reding@...il.com>,
	Derek Barbosa <debarbos@...hat.com>,
	linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: [PATCH printk v2 0/2] Fix reported suspend failures

This is v2 of a series to address multiple reports [0][1]
(+ 2 offlist) of suspend failing when NBCON console drivers are
in use. With the help of NXP and NVIDIA we were able to isolate
the problem and verify the fix.

v1 is here [2].

The first NBCON drivers appeared in 6.13, so currently there is
no LTS kernel that requires this series. But it should go into
6.17.x and 6.18.

The changes since v1:

- For printk_trigger_flush() add support for all flush types
  that are available. This will prevent printk_trigger_flush()
  from trying to inappropriately queue irq_work after this
  series is applied.

- Add WARN_ON_ONCE() to the printk irq_work queueing functions
  in case they are called when irq_work is blocked. There
  should never be (and currently are no) such callers, but
  these functions are externally available.

John Ogness

[0] https://lore.kernel.org/lkml/80b020fc-c18a-4da4-b222-16da1cab2f4c@nvidia.com
[1] https://lore.kernel.org/lkml/DB9PR04MB8429E7DDF2D93C2695DE401D92C4A@DB9PR04MB8429.eurprd04.prod.outlook.com
[2] https://lore.kernel.org/lkml/20251111144328.887159-1-john.ogness@linutronix.de

John Ogness (2):
  printk: Allow printk_trigger_flush() to flush all types
  printk: Avoid scheduling irq_work on suspend

 kernel/printk/internal.h |  8 ++--
 kernel/printk/nbcon.c    |  9 ++++-
 kernel/printk/printk.c   | 81 ++++++++++++++++++++++++++++++++--------
 3 files changed, 78 insertions(+), 20 deletions(-)


base-commit: e9a6fb0bcdd7609be6969112f3fbfcce3b1d4a7c
-- 
2.47.3